S. Patricia Stock
- (520) 621-0868
- PHARMACY-MICRO, Rm. 201
- TUCSON, AZ 85721
- spstock@arizona.edu
Biography
Dr. Stock earned her B.S. in Biology (emphasis in Zoology) and her Ph.D. in Natural Sciences (emphasis in Parasitology and Nematology) at the Universidad Nacional de La Plata, Argentina. After completion of her degree, she joined the Center for Parasites and Vector Studies (CEPAVE, Univ. of La Plata) and soon after held a teaching faculty position at the Dept. of Zoology, Universidad Nacional de La Plata. She held a position as a visiting scientist at the University of California, Davis, where she continued her research on entomopathogenic nematodes in Harry Kaya’s laboratory. In 1997, she accepted a NSF-funded post-doctoral position with Steve Nadler at UC-Davis to study free-living cephalobid nematodes integrating classical and molecular phylogenetics. In 1998, Dr. Stock was hired as Senior Museum Scientist (Assistant Curator) of the U.C. Davis Nematode Collection. Besides her curatorial responsibilities, Dr. Stock remained active in research collaborating in several research projects with colleagues from the USA, Europe, Asia, Africa and Latin America. Since 2001, Dr. Stock has been at the University of Arizona. Currently, she is the Director of the School of Animal and Comparative Biomedical Sceinces where she also helds her Professor appointment. She is Joint Professor in the Department of Entomology and is a Professor in the Honors College.
Her research program focuses on the study of insect pathogens as model systems. Specifically, the focus is on entomopathogenic nematodes (aka EPN) Steinernema and Heterorhabditis spp. Nematoda:Steinernematidae, Heterorhabditidae) and their bacterial symbionts Xenorhabdus and Photorhabdus spp (Enterobacteriaceae) which represent an emerging model of terrestrial animal-microbe interactions.EPN symbiotic bacteria also represent a new and rich source of novel bioactive molecules with insecticidal, nematicidal, antibiotic, and antimycotic properties. In this respect, her laboratory is involved in the discovery and characterization secondary metabolites of a newly discovered Photorhabdus bacterium that is native to SW USA. We also investigate eukaryote-prokaryote mutualisms as models for understanding trophic complexities and interactions in food webs. A continued research focus is nematode biodiversity. Over her career, Dr. Stock has been actively engaged in survey and inventory projects in different geographic regions of the world with the overarching goal of understanding the ecology and behavior of these entomopathogens but also to develop them as effective biological control agents against major agricultural and urban pests. She has authored and co-authored over 120 refereed papers, eleven chapters in books regarding systematics, biology of insect-parasitic and free-living nematodes. She was the senior editor of the book “Insect Pathogens: Molecular Approaches and Techniques, published by CABI Publishing.
Dr. Stock has served as associate editor (Journal of Nematology, Insect Science, Biocontrtol Science and Technology, Nematropica), editorial board member and reviewer of numerous national and international journals including Nematropica, Insect Science, Biocontrol Science and Technology. Dr. Stock has been an active member of various societies including the Society of Nematologists (SON), Society for Invertebrate Pathology (SIP), Organization of Nematologists of Tropical America (ONTA), International Symbiosis Society (ISS), and Entomological Society of America (ESA).
Degrees
- Post Doctoral Training
- University of California Davis, Davis, US
- PhD Natural Sciences
- Universidad Nacional de la Plata Facultad de Ciencias Naturales y Museo, La Plata, AR
- Ph.D. Natural Sciences
- Universidad Nacional de La Plata, Argentina, La Plata, Buenos Aires
- Entomophilic and Entomopathogenic Nematodes of Coleopteran Pests from the Pampean Region
- B.S. Biology/ Zoology
- Universidad Nacional de La Plata, Argentina, La Plata, Argentina
- Bachelors in Biology (major Zoology)
- Universidad Nacional de la Plata, La Plata, AR
Work Experience
- University of Arizona (2019 - 2021)
- University of Arizona, Tucson (2018 - 2021)
- Dept. Entomology, University of Arizona (2011 - 2021)
- University of Arizona, Tucson (2005 - Ongoing)
Awards
- Founders Lecture Award
- Society for Invertebrate Pathology, Summer 2018
- SIP President Nomination
- Society for Invertebrate Pathology, Spring 2018 (Award Nominee)
- Founders Lecturer
- Society for Invertebrate Pathology., Winter 2017 (Award Finalist)
- Faculty Fellow
- Battle of Little Big Horn Leadership Program, Billings MT, USA, Fall 2017
- Honors Professor
- The Honors College, Fall 2017
- The Honors College, University of Arizona, Fall 2016
- The Honors College, University of Arizona, Fall 2015
- The Honors College, University of Arizona, Fall 2014
- Honors College, Spring 2013
- Elected Secretary/Treasurer for the Nematode Division
- Society for Invertebrate Pathology, Summer 2016
- Vice President for Education
- International Symbiosis Society, Spring 2016
- Vice President
- Vice President (Education), International Symbiosis Society, Summer 2015
- Organization of Nematologists of Tropical America (ONTA), Summer 2008
- David E. Cox Faculty Teaching Award
- College of Agriculture and Life Sciences, University of Arizona, Fall 2014
- Shirley O'Brien Diversity Award
- CALS, Spring 2013
- Secretary
- Society for Invertebrate Pathology. Elected by society's members (~350 members from various nations), Summer 2012
- Society for Invertebrate Pathology, Nominations Committee,, Spring 2011 (Award Nominee)
- Academic Leadership Fellow
- UA Academic Leadership Program, Spring 2011
- President
- Organization of Nematologists of Tropical America (ONTA), Summer 2009
- Outstanding Faculty Mentor
- Undergraduate Biology Research Program, University of Arizona, Spring 2009 (Award Nominee)
- Undergraduate Biology Research Program, University of Arizona, Spring 2008 (Award Nominee)
- Fulbright Scholar
- The Fulbright Foundation, Senior Specialist Program, Summer 2006
- Chair, Entomophilic Nematode Division
- Society of nematologists, Summer 2004
- Trustee
- Society for Invertebrate Pathology, Executive Council, Summer 2004
- Vice Chair, Entomophilic Nematode Division
- Society of Nematologists, Summer 2003
- Chair, Nematode Division
- Society for Invertebrate Pathology, Summer 2002
Licensure & Certification
- Certificate in College Teaching, Universidad Nacional de la Plata (1991)
Interests
Teaching
Insect Pathology, Symbiosis,
Research
Host-symbiont interactions, Insect Pathologens, Nematology, Multitrophic interactions
Courses
2020-21 Courses
-
Directed Research
ACBS 492 (Spring 2021) -
Directed Research
PLS 492 (Spring 2021) -
Dissertation
MIC 920 (Spring 2021) -
Honors Thesis
PSIO 498H (Spring 2021) -
Research
MIC 900 (Spring 2021) -
Special Topics in Science
HNRS 195I (Spring 2021) -
Thesis
EIS 910 (Spring 2021) -
Directed Research
ACBS 492 (Fall 2020) -
Dissertation
EIS 920 (Fall 2020) -
Dissertation
MIC 920 (Fall 2020) -
Honors Thesis
PSIO 498H (Fall 2020) -
Independent Study
MIC 399 (Fall 2020) -
Research
EIS 900 (Fall 2020) -
Research
MIC 900 (Fall 2020)
2019-20 Courses
-
Directed Research
ACBS 492 (Spring 2020) -
Directed Research
PLS 492 (Spring 2020) -
Honors Independent Study
MCB 399H (Spring 2020) -
Honors Thesis
ACBS 498H (Spring 2020) -
Research
EIS 900 (Spring 2020) -
Research
MIC 900 (Spring 2020) -
Special Topics in Science
HNRS 195I (Spring 2020) -
Thesis
MIC 910 (Spring 2020) -
Directed Research
ENTO 492 (Fall 2019) -
Honors Independent Study
MCB 399H (Fall 2019) -
Independent Study
MIC 399 (Fall 2019) -
Research
EIS 900 (Fall 2019) -
Research
MIC 900 (Fall 2019) -
Thesis
MIC 910 (Fall 2019)
2018-19 Courses
-
Directed Research
ACBS 492 (Spring 2019) -
Dissertation
EIS 920 (Spring 2019) -
Honors Independent Study
MCB 299H (Spring 2019) -
Honors Thesis
ACBS 498H (Spring 2019) -
Honors Thesis
BIOC 498H (Spring 2019) -
Honors Thesis
MIC 498H (Spring 2019) -
Independent Study
MIC 499 (Spring 2019) -
Research
MIC 900 (Spring 2019) -
Special Topics in Science
HNRS 195I (Spring 2019) -
Directed Research
ACBS 492 (Fall 2018) -
Directed Research
PSIO 492 (Fall 2018) -
Dissertation
EIS 920 (Fall 2018) -
Honors Independent Study
MCB 299H (Fall 2018) -
Honors Thesis
BIOC 498H (Fall 2018) -
Honors Thesis
MIC 498H (Fall 2018) -
Independent Study
MIC 599 (Fall 2018) -
Research
MIC 900 (Fall 2018)
2017-18 Courses
-
Directed Research
ENTO 392 (Spring 2018) -
Directed Research
ENTO 492 (Spring 2018) -
Dissertation
EIS 920 (Spring 2018) -
Honors Independent Study
ACBS 399H (Spring 2018) -
Honors Independent Study
BIOC 499H (Spring 2018) -
Honors Independent Study
ENTO 499H (Spring 2018) -
Research
MIC 900 (Spring 2018) -
Special Topics in Science
HNRS 195I (Spring 2018) -
Directed Research
ENTO 392 (Fall 2017) -
Directed Research
ENTO 492 (Fall 2017) -
Dissertation
EIS 920 (Fall 2017) -
Honors Independent Study
BIOC 499H (Fall 2017) -
Honors Independent Study
ENTO 499H (Fall 2017) -
Living In Symbiosis
ACBS 310 (Fall 2017) -
Living In Symbiosis
ECOL 310 (Fall 2017) -
Living In Symbiosis
ENTO 310 (Fall 2017) -
Living In Symbiosis
MIC 310 (Fall 2017) -
Research
MIC 900 (Fall 2017) -
Thesis
MIC 910 (Fall 2017)
2016-17 Courses
-
Directed Research
ECOL 392 (Spring 2017) -
Directed Research
ENTO 392 (Spring 2017) -
Directed Research
PLS 492 (Spring 2017) -
Dissertation
EIS 920 (Spring 2017) -
Honors Independent Study
BIOC 399H (Spring 2017) -
Honors Thesis
ECOL 498H (Spring 2017) -
Research
EIS 900 (Spring 2017) -
Research
MIC 900 (Spring 2017) -
Thesis
MIC 910 (Spring 2017) -
Directed Research
ECOL 392 (Fall 2016) -
Directed Research
ECOL 492 (Fall 2016) -
Directed Research
ENTO 392 (Fall 2016) -
Directed Research
PLS 392 (Fall 2016) -
Honors Independent Study
PSIO 399H (Fall 2016) -
Honors Thesis
ECOL 498H (Fall 2016) -
Independent Study
ECOL 199 (Fall 2016) -
Living In Symbiosis
ACBS 310 (Fall 2016) -
Living In Symbiosis
ECOL 310 (Fall 2016) -
Living In Symbiosis
ENTO 310 (Fall 2016) -
Living In Symbiosis
MIC 310 (Fall 2016) -
Meth In Insect Science
EIS 700 (Fall 2016) -
Research
EIS 900 (Fall 2016) -
Research
MIC 900 (Fall 2016) -
Special Topics in Science
HNRS 195I (Fall 2016) -
Thesis
MIC 910 (Fall 2016)
2015-16 Courses
-
Research
MIC 900 (Summer I 2016) -
Directed Research
ECOL 392 (Spring 2016) -
Directed Research
ECOL 492 (Spring 2016) -
Directed Research
ENTO 492 (Spring 2016) -
Directed Rsrch
MCB 492 (Spring 2016) -
Honors Thesis
ECOL 498H (Spring 2016) -
Research
EIS 900 (Spring 2016) -
Research
MIC 900 (Spring 2016)
Scholarly Contributions
Books
- Wild, A., Reed, A., Crocetti, G., & Stock, S. P. (2019). Nema and the Xenos: A Story of Soil Cycles.. Australia: CSIRO PUBLISHING.
- Stock, S. P., Slingerland, J., & Lamoreaux, M. (2011). Worms in the Classroom.More info2011
Chapters
- Stock, S. P. (2015). Nematoda. In Invertebrates 3rd edition. Eds. R. Brusca, S. Shuster and W. More. Sinauer Associates.
- Stock, S. P. (2015). Diversity, Biology and Evolutionary Relationships. In Nematode pathogenesis of insects and other pests - ecology and applied technologies for sustainable plant and crop protection. Eds. A. Ciancio and R. Campos-Herrera. Springer.
- Stock, S. P. (2012). Nematode Parasites, Pathogens and Associates of Invertebrates. In Book Manual of techniques in Invertebrated Pathology.More infoEditor(s): Lacey, L
- Stock, S., & Goodrich-Blair, H. (2012). Nematode parasites, pathogens and associates of insects and invertebrates of economic importance.. In Manual of Techniques in Insect Pathology, 2nd edition(pp 373-426).More infoEditor(s): Lacey, L
Journals/Publications
- Kochanowsky, R., Bradshaw, C., Forlastro, I., & Stock, S. P. (2020). Xenorhabdus bovienii strain jolietti uses a type 6 secretion system to kill closely related Xenorhabdus strains.. FEMS microbiology ecology, 96(8). doi:https://doi.org/10.1093/femsec/fiaa073
- Stock, S. P., Thappeta, K., Ciezki, K., Morales-Soto, N., Wesener, S., Goodrich-Blair,, H., & Forst, S. (2020). R-type bacteriocins of Xenorhabdus bovienii determine the outcome of interspecies competition in a natural host environment. Microbiology, 166(1), 1074-1087.
- Allen, J., Peterson, B., Stock, S. P., & Hoffman, R. (2018). Mild thermal stress affects Steinernema carpocapsae infective juvenile survival but not protein content. PeerJ.
- Campos-Herrera, R., El-Borai, F., Duncan, L., & Stock, S. P. (2019). Steinernema khuongi n. sp.(Panagrolaimomorpha, Steinernematidae), a new entomopathogenic nematode species from Florida, USA. Journal of helminthology,. Journal of helminthology, 93(2), 226-241.
- Kusakabe, A., Peterson, B., Rivera Orduno, B., & Stock, S. P. (2018). Ecological characterization of Heterorhabditis sonorensis (Caborca strain) (Nematoda: Heterorhabditidae), a warm-adapted entomopathogenic nematode from Mexico. Zoology.
- Petterson, B., Allen, J., Hoffman, R., & Stock, S. P. (2019). Mild thermal stress affects Steinernema carpocapsae infective juvenile survival but not protein content. 167, p.107251.. Journal of Invertebrate Pathology,, 167, 107251.
- Roder, A. C., Wang, Y., Butcher, R. A., & Stock, S. P. (2019). Influence of symbiotic and non-symbiotic bacteria on pheromone production in nematodes (Nematoda, Steinernematidae).. J. Experimental Biology, 222(18), jeb212068.
- Stock, S. P. (2019). Partners in crime: symbiont-assisted resource acquisition in Steinernema entomopathogenic nematodes.. Current opinion in insect science, 32, 22-27..
- Norris, E. E., Stock, S. P., Castrillo, L. A., Williams, D. W., & Hajek, A. E. (2018). Characterisation of the dimorphic Deladenus beddingi n. sp. and its associated woodwasp and fungus. Nematology, 20(10), 1-17. doi:https://doi.org/10.1163/15685411-00003188
- Roder, A. C., & Stock, S. P. (2018). Influence of Xenorhabdus (Gamma-Proteobacteria: Enterobacteriaceae) symbionts on gonad postembryonic development in Steinernema (Nematoda: Steinernematidae) nematodes.. Journal of invertebrate pathology, 153, 65-74.. doi:https://doi.org/10.1016/j.jip.2018.02.015
- Stock, S. P. (2018). Partners in crime: symbiont-assisted resource acquisition in Steinernema entomopathogenic nematodes. Current Opinion in Insect Science, 32, 22-27. doi:https://doi.org/10.1016/j.cois.2018.10.006
- Stock, S. P., & McQuade, R. (2018). Secretion Systems and Secreted Proteins in Gram-Negative Entomopathogenic Bacteria: Their Roles in Insect Virulence and Beyond. Insects, 9(2), 1-16. doi:, 68; https://doi.org/10.3390/insects9020068
- Stock, S. P., Campos-Herrera, R., El-Borai, F., & Ducan, L. (2018). Steinernema khuongi n. sp. (Panagrolaimomorpha, Steinernematidae) a new entomopathogenic nematode species from Florida, USA. Journal of helminthology, 1-16. doi:https://doi.org/10.1017/S0022149X18000081
- Stock, S. P., Kuskabe, A., & Orozco, R. (2017). Secondary Metabolites Produced by Heterorhabditis Symbionts and Their Application in Agriculture: What We Know and What to Do Next. Journal of Nematology, 49(4), 373–383..
- McMullen, J. G., McQuade, R., Ogier, J., Gaudriault, S., & Stock, S. P. (2017). Variable virulence phenotype of Xenorhabdus bovienii (γ-Proteobacteria: Enterobacteriaceae) in the absence of their vector hosts. Microbiology, 163, 510-522. doi:doi: 10.1099/mic.0.000449
- McMullen, J., Peterson, B., Forst, S., Goodrich-Blair, H., & Stock, S. P. (2017). Fitness costs of symbiont switching using entomopathogenic nematodes as a model. BMC Evolutionary Biology.
- Castagnola, A., Mulley, G., Davis, N., Waterfield, N., & Stock, S. P. (2016). Transcript abundance of Photorhabdus insect related (Pir) toxin in Manduca sexta and Galleria mellonella infections. Toxins, 8(10), 287. doi:10.3390/toxins8100287
- Ciezki, K., Murfin, K., Forst, S., Stock, S. P., & Goodrich-Blair, H. (2016). R-type bacteriocins in related strains of Xenorhabdus bovienii: Xenorhabdicin tail fiber modularity and contribution to competitiveness. FEMS Microbiology Letters.
- Molnar, I., Stock, S. P., & 2 co-authors, . (2016). Bioprospecting for secondary metabolites in the entomopathogenic bacterium Photorhabdus luminescens subsp. sonorensis. Journal of Invertebrate Pathology, 141, 45-52. doi:10.1016/j.jip.2016.09.008
- Orozco, R. A., Molnar, I., & Stock, S. P. (2016). Bioprospecting of secondary metabolites produced by the entomopathogenic bacterium Photorhabdus luminescens subsp. sonorensis. Journal of Invertebrate Pathology.
- Dillman, A., Machietto, M., Porter, C., Rogers, A., Willliams, B., Antoshechkin, I., Lee, M., Goodwin, Z., Lu, X., Lewis, E., Goodrich-Blair, H., Stock, S. P., Adams, B., Stenberg, P., & Mortazavi, A. (2015). Comparative genomics of Steinernema reveals deeply conserved regulatory networks in nematodes. Genome Biology.
- Murfin, K., Lee, M., Klaasen, J., McDonald, B., Larget, B., Stock, S. P., Goodrich-Blair, H., Forst, S., & Currie, C. (2015). Xenorhabdus bovienii bacterial strain diversity impacts coevolution and symbiotic maintenance with Steinernema spp. nematode hosts. eBio.
- Bisch, G., Pages, S., McMullen, J., Stock, S. P., Duvic, B., Givadaun, A., & Gaudriault, S. (2014). Xenorhabdus bovienii CS03, the bacterial symbiont of the entomopathogenic.. J. Invert. Pathology, 124, 15–22..
- Castagnola, A., & Stock, S. P. (2014). Common virulence factors and tissue targets of entomopathogenic bacteria for biological control of lepidopteran pests. Insects, 5(1), 139-166.More infoAbstract: This review focuses on common insecticidal virulence factors from entomopathogenic bacteria with special emphasis on two insect pathogenic bacteria Photorhabdus (Proteobacteria: Enterobacteriaceae) and Bacillus (Firmicutes: Bacillaceae). Insect pathogenic bacteria of diverse taxonomic groups and phylogenetic origin have been shown to have striking similarities in the virulence factors they produce. It has been suggested that the detection of phage elements surrounding toxin genes, horizontal and lateral gene transfer events, and plasmid shuffling occurrences may be some of the reasons that virulence factor genes have so many analogs throughout the bacterial kingdom. Comparison of virulence factors of Photorhabdus, and Bacillus, two bacteria with dissimilar life styles opens the possibility of re-examining newly discovered toxins for novel tissue targets. For example, nematodes residing in the hemolymph may release bacteria with virulence factors targeting neurons or neuromuscular junctions. The first section of this review focuses on toxins and their context in agriculture. The second describes the mode of action of toxins from common entomopathogens and the third draws comparisons between Gram positive and Gram negative bacteria. The fourth section reviews the implications of the nervous system in biocontrol. © 2014 by the authors; licensee MDPI, Basel, Switzerland.
- McMullen, J., & Stock, S. P. (2014). In vivo and in vitro rearing of entomopathogenic nematodes (Steinernematidae and Heterorhabditidae).. J. Visualualized Experiments, 91, e52096.
- Miranda, V. A., Navarro, P. D., Davidowitz, G. -., Bronstein, J. -., & Stock, S. P. (2014). The effect of insect host age and diet on the fitness of the entomopathogenic nematode - bacteria mutualism. Symbiosis. Symbiosis.
- Navarro, P. D., Navarro, P. D., McMullen, J. G., McMullen, J. G., Stock, S. P., & Stock, S. P. (2014). Interactions between the entomopathogenic nematode Heterorhabditis sonorensis (Nematoda: Heterorhabditidae) and the saprobic fungus Fusarium oxysporum (Ascomycota: Hypocreales). Journal of Invertebrate Pathology, 115(1), 41-47.More infoAbstract: In this study, we assessed the effect of the saprobic fungus, Fusarium oxysporum (Ascomycota: Hypocreales) on the fitness of the entomopathogenic nematode Heterorhabditis sonorensis (Caborca strain). Sand column assays were considered to evaluate the effect of fungal mycelia on infective juvenile (IJ) movement and host access. Additionally, we investigated the effect of fungal spores on the nematodes' ability to search for a host, its virulence, penetration efficiency and reproduction. Three application timings were considered to assess interactions between the fungus and the nematodes. In vitro assays were also considered to determine the effect of fungal extracts on the nematode's symbiotic bacteria. Our observations indicate that presence and age of fungal mycelia significantly affect IJ movement in the sand columns and their ability to establish in the host. These results were also reflected in a reduced insect mortality. In particular, treatments with the 15. days old mycelia showed a significant reduction in insect mortality and penetration efficiency. Presence of fungal spores also impacted nematode virulence and reproduction. In particular, two of the application timings tested (simultaneous [EPN and fungal spores applied at the same time] and alternate I [EPN applied first, fungus applied 24. h later]) resulted in antagonistic interactions. Moreover, IJ progeny was reduced to half in the simultaneous application. In vitro assays revealed that fungal extracts at the highest concentration tested (10. mg/ml) inhibited the growth of the symbiotic bacteria. Overall, these results suggest that saprobic fungi may play an important role in regulating. EPN populations in the soil, and that they may be one of the factors that impact nematode survival in the soil and their access to insect hosts. © 2013 Elsevier Inc.
- Navarro, P., McMullen, J., & Stock, S. P. (2014). Effect of dinotefuran, indoxacarb, and imidacloprid on survival and fitness of two Arizona-native entomopathogenic nematodes against Helicoverpa zea(Lepidoptera: Noctuidae).. Nematropica, 44, 64-73.
- Orozco, R., Lee, M., & Stock, S. P. (2014). Soil Sampling and Isolation of Entomopathogenic Nematodes (Steinernematidae, Heterorhabditidae).89:1-8;. J. Visualualized Experiments, 89, 1-8.
- Çimen, H., Lee, M. -., Hatting, J., Hazir, S., & Stock, S. P. (2014). Steinernema innovationi n. sp. (Panagrolaimomorpha: Steinernematidae), a new entomopathogenic nematode species from South Africa. Journal of Helminthology.More infoAbstract: Morphological and molecular sequence data were combined with cross-hybridization studies and used to identify a new Steinernema sp. from Free State, South Africa. Molecular and morphological data indicate that the new species belongs to the 'glaseri-group' of Steinernema spp. Key morphological diagnostic characters for S. innovationi n. sp. include the morphometric features of the third-stage infective juveniles: total body length = 1054 (1000-1103) μm, tail length = 108 (97-117) μm, location of the excretory pore = 88 (82-91) μm, and D% = 58 (54-63), E% = 115 (104-137) and H% = 43 (37-46). Additionally, the morphology of the spicules and gubernaculum of the first-generation males are considered key diagnostic traits. Steinernema innovationi n. sp. was also characterized by analysis of both rDNA and mitochondrial gene sequence data, which further indicate the uniqueness of this Steinernema species. Copyright © Cambridge University Press 2014.
- Miranda, V. A., Navarro, P. D., Davidowitz, G. -., Bronstein, J. -., & Stock, S. P. (2013). The effect of insect host age and diet on the fitness of the entomopathogenic nematode - bacteria mutualism. Symbiosis. Symbiosis, 61, 145-153. doi:DOI 10.1007/s13199-013-0266-7
- Miranda, V. A., Navarro, P. D., Davidowitz, G. -., Bronstein, J. -., Stock, S. P., Miranda, V. A., Navarro, P. D., Davidowitz, G. -., Bronstein, J. -., & Stock, S. P. (2015). The effect of insect host age and diet on the fitness of the entomopathogenic nematode - bacteria mutualism. Symbiosis. Symbiosis, 61, 145-153. doi:DOI 10.1007/s13199-013-0266-7
- Orozco, R. A., Hill, T., & Stock, S. P. (2013). Characterization and phylogenetic relationships of photorhabdus luminescens subsp. sonorensis (γ-proteobacteria: Enterobacteriaceae), the bacterial symbiont of the entomopathogenic nematode heterorhabditis sonorensis (nematoda: Heterorhabditidae). Current Microbiology, 66(1), 30-39.More infoPMID: 23053483;Abstract: Photorhabdus are motile Gram-negative bacteria that have a mutualistic association with Heterorhabditis nematodes (Heterorhabditidae). These bacteria possess peculiar biochemical characteristics such as inability to reduce nitrates, and the capacity to ferment only a limited number of carbohydrates. Heterorhabditis nematodes vector the bacteria from one insect host to another and also provide shelter to the bacteria from soil stressors and antagonists. Once inside the insect host, the bacterial symbionts are released and produce toxins and secondary metabolites and broad-spectrum antibiotics, which kill the host by septicemia within 48 h. At present, three Photorhabdus spp. have been identified: P. luminescens, P. temperata, and P. asymbiotica, and many subspecies have also been described. Characterization of new species and subspecies has been based on sequence data, mostly of the 16S rDNA, and also of a selection of protein coding genes. In addition to this, phenotypic traits including temperature growth, colony morphology, color, light production, carbohydrate response, and assimilation, among others, have been considered. In this study, we characterize the bacterial symbiont of Heterorbabditis sonorensis, a recently discovered entomopathogenic nematode species form the Sonoran desert in Arizona, USA. A selection of classic biochemical and molecular methods including sequence data of six genes: 16s rDNA, and four protein coding genes: gyrB, recA, gltX, and dnaN were considered. Evolutionary relationships of this new Photorhabdus subsp. were inferred considering maximum parsimony and Bayesian analyses. © 2012 Springer Science+Business Media, LLC.
- Stock, S. P., Miranda, V., Navarro, P., Davidowitz, G. -., & Bronstein, J. -. (2013). Effect of insect host age and diet on the fitness of the entomopathogenic nematode-bacteria mutualism.. Symbiosis, DOI 10.1007/s13199-013-0266-7.(61), 145-153.
- Stock, S. P., Navarro, P., & McMullen II, J. (2013). Interactions between the entomopathogenic nematode Heterorhabditis sonorensis (Nematoda: Heterorhabditidae) and the saprobic fungus Fusarium oxysporum (Ascomycota: Hypocreales). Journal of Invertebrate pathology, 115, 41-47.
- Stock, S., Stock, S. P., Orozco, R. A., & Hill, T. (2013). Characterization and phylogenetic relationships of Photorhabdus luminescens subsp. sonorensis (Gamma-Proteobacteria: Enterobacteriaceae), the bacterial symbiont of the entomopathogenic nematode Heterorhabditis sonorensis (Nematoda: Heterorhabditidae). Current microbiology, 66(1).
- Campos-Herrera, R., Barbercheck, M., Hoy, C. W., & Stock, S. P. (2012). Entomopathogenic nematodes as a model system for advancing the frontiers of ecology. Journal of Nematology, 44(2), 162-176.More infoAbstract: Entomopathogenic nematodes (EPNs) in the families Heterorhabditidae and Steinernematidae have a mutualistic- symbiotic association with enteric γ-Proteobacteria (Steinernema-Xenorhabdus and Heterorhabditis- Photorhabdus), which confer high virulence against insects. EPNs have been studied intensively because of their role as a natural mortality factor for soil-dwelling arthropods and their potential as biological control agents for belowground insect pests. For many decades, research on EPNs focused on the taxonomy, phylogeny, biogeography, genetics, physiology, biochemistry and ecology, as well as commercial production and application technologies. More recently, EPNs and their bacterial symbionts are being viewed as a model system for advancing research in other disciplines such as soil ecology, symbiosis and evolutionary biology. Integration of existing information, particularly the accumulating information on their biology, into increasingly detailed population models is critical to improving our ability to exploit and manage EPNs as a biological control agent and to understand ecological processes in a changing world. Here, we summarize some recent advances in phylogeny, systematics, biogeography, community ecology and population dynamics models of EPNs, and describe how this research is advancing frontiers in ecology. © The Society of Nematologists 2012.
- Dillman, A. R., Chaston, J. M., Adams, B. J., Ciche, T. A., Goodrich-Blair, H., Stock, S. P., & Sternberg, P. W. (2012). An entomopathogenic nematode by any other name. PLoS Pathogens, 8(3).More infoPMID: 22396642;PMCID: PMC3291613;
- Gassmann, A., Hannon, E., Sisterson, M., , Y., Tabashnik, B., & Stock, S. (2012). Effects of entomopathogenic nematodes on evolution of pink bollworm resistance to Bacillus thuringiensis Toxin Cry1Ac. J Econom Entomol, 105, 994-1005.
- Kamminga, K. L., Davis, J. A., Stock, S. P., & Richter, A. R. (2012). First report of a mermithid nematode infecting Piezodorus guildinii and Acrosternum hilare (Hemiptera: Pentatomidae) in the United States. Florida Entomologist, 95(1), 214-217.More infoAbstract: A mermithid nematode emerged from stink bugs, Acrosternum hilare and Piezodorus guildinii, collected from Louisiana soybean fields. Photographs of this parasite are presented. An analysis conducted by amplifying 18S rDNA revealed that the nematode belongs to the genus Hexamermis. A BLAST search indicated that the sequence (696 bp) has the closest match to Hexamermis agrotis Wang et al. 18S ribosomal RNA gene. This is the first report of a Hexamermis sp. infecting A. hilare worldwide and a mermithid infecting P. guildinii in the United States.
- Kim, S. K., Kim, S. K., Flores-Lara, Y., Flores-Lara, Y., Stock, S. P., & Stock, S. P. (2012). Morphology and ultrastructure of the bacterial receptacle in Steinernema nematodes (Nematoda: Steinernematidae). Journal of Invertebrate Pathology, 110(3), 366-374.More infoPMID: 22564260;Abstract: Infective juveniles of entomopathogenic nematodes in the genus . Steinernema harbor symbiotic bacteria, . Xenorhabdus spp., in a discrete structure located in the anterior portion of the intestine known as the 'bacterial receptacle' (formerly known as the bacterial or intestinal vesicle). The receptacle itself is a structured environment in which the bacteria are spatially restricted. Inside this receptacle, bacterial symbionts are protected from the environment and grow to fill the receptacle. Until now, no comparative study across different . Steinernema spp. has been undertaken to investigate if morphological variation in this structure exists at the interspecific level. In this study, we examined the bacterial receptacles of 25 . Steinernema spp. representatives of the currently accepted five evolutionary clades. Our observations confirmed the bacterial receptacle is a modification of the two most anterior cells of the ventricular portion of the intestine. Size of the bacterial receptacle varied across the examined species. . Steinernema monticolum (clade II) had the largest receptacle of all examined species (average: 46. ×. 17. μm) and . S. rarum (no clade affiliation) was noted as the species with the smallest observed receptacle (average: 8. ×. 5. μm). At the morphological level, species can be grouped into two categories based on the presence or absence of vesicle within the receptacle. The receptacles of all examined species harbored an intravesicular structure (IVS) with variable morphology. All examined taxa members of the 'feltiae' (clade III) and 'intermedium' (clade II) clades were characterized by having a vesicle. This structure was also observed in . S. diaprepesi (clade V), . S. riobrave (clade IV) and . S. monticolum (clade I). © 2012 Elsevier Inc..
- Kim, S., Flores-Lara, Y., & Stock, S. (2012). Morphology and ultrastructure of the bacterial receptacle in Steinernema nematodes. J Invert Pathol, 110, 366-374.
- Orozco, R., Hill, T., & Stock, S. (2012). Characterization and phylogenetic relationships of Photorhabdus luminescens subsp Sonorensis. Current Microbiology, 66.
- Stock, S. P., & Goodrich-Blair, H. (2012). Nematode parasites, pathogens and associates of insects and invertebrates of economic importance. Manual of Techniques in Invertebrate Pathology, 373-426.
- Stock, S. P., Dillman, A., Chaston, J., Adams, B., Ciche, T., Goodrich-Blair, H., SP, S., & Sternberg, P. (2012). An entomopathogenic nematode by any other name. PLOS Pathogen, 8, 1-4.
- Stock, S. P., Stock, S. P., Lee, M., Lee, M., Flores-Lara, Y., & Flores-Lara, Y. (2012). The rectal glands of Heterorhabditis bacteriophora (Rhabditida: Heterorhabditidae) hermaphrodites and their role in symbiont transmission. Journal of Invertebrate Pathology, 110(1), 135-138.More infoPMID: 22465627;Abstract: Differential interference contrast, transmission electron and epifluorescence microscopy techniques were employed to examine the ultrastructure of the rectal glands in . Heterorhabditis bacteriophora hermaphrodites, with special attention to the location of . Photorhabdus bacteria symbionts within these structures. Three rectal glands were clearly visualized in all examined specimens, with two glands positioned sub-ventrally and another gland located dorsally. The dorsal rectal gland in all examined specimens is larger than the subventral ones. Our observations indicate that . Photorhabdus bacteria do not colonize the rectal glands of . H. bacteriophora hermaphrodites, but rather are present in the most posterior-intestinal cells. © 2012.
- Stock, S., Lee, M., & Flores-Lara, Y. (2012). The rectal glands of Heterorhabditis bacteriophora. Invert Pathol, 101, 135-138.
- Sugar, D. R., Murfin, K. E., Chaston, J. M., Andersen, A. W., Richards, G. R., deLéon, L., Baum, J. A., Clinton, W. P., Forst, S., Goldman, B. S., Krasomil-Osterfeld, K. C., Slater, S., Stock, S. P., & Goodrich-Blair, H. (2012). Phenotypic variation and host interactions of Xenorhabdus bovienii SS-2004, the entomopathogenic symbiont of Steinernema jollieti nematodes. Environmental Microbiology, 14(4), 924-939.More infoPMID: 22151385;PMCID: PMC3307839;Abstract: Xenorhabdus bovienii (SS-2004) bacteria reside in the intestine of the infective-juvenile (IJ) stage of the entomopathogenic nematode, Steinernema jollieti. The recent sequencing of the X.bovienii genome facilitates its use as a model to understand host - symbiont interactions. To provide a biological foundation for such studies, we characterized X.bovienii in vitro and host interaction phenotypes. Within the nematode host X.bovienii was contained within a membrane bound envelope that also enclosed the nematode-derived intravesicular structure. Steinernema jollieti nematodes cultivated on mixed lawns of X.bovienii expressing green or DsRed fluorescent proteins were predominantly colonized by one or the other strain, suggesting the colonizing population is founded by a few cells. Xenorhabdus bovienii exhibits phenotypic variation between orange-pigmented primary form and cream-pigmented secondary form. Each form can colonize IJ nematodes when cultured in vitro on agar. However, IJs did not develop or emerge from Galleria mellonella insects infected with secondary form. Unlike primary-form infected insects that were soft and flexible, secondary-form infected insects retained a rigid exoskeleton structure. Xenorhabdus bovienii primary and secondary form isolates are virulent towards Manduca sexta and several other insects. However, primary form stocks present attenuated virulence, suggesting that X.bovienii, like Xenorhabdus nematophila may undergo virulence modulation. © 2011 Society for Applied Microbiology and Blackwell Publishing Ltd.
- Kaminga, K., Davis, J., Stock, S., & Richter, A. (2011). Mermithid Nematode Infecting Piezodorus Guildinii. The Florida Entomologist, 94, 890-894.
- Stock, S., Bird, D. M., Ghedin, E., & Goodrich-Blair, H. (2011). Abstracts of NEMASYM: The Third Nematode-Bacteria Symbioses Research Coordination Network Meeting. Symbiosis, 1-13.
- Stock, S., Bird, D., Ghedin, E., & Goodrich-Blair, H. (2011). Abstracts of NEMASYM: The Third Nematode-Bacteria. Symbiosis, 55, 1-13.
- Sugar, D., Murfin, K., Chaston, J., Andersen, A., Richards, G., deLeon, L., Baum, J., Clinton, W., Forst, S., Goldman, B., Krasomil-Osterfeld, K., Slater, S., Stock, S., & Goodrich-Blair, H. (2011). Phenotypic variation and host interactions of Xenorhabdus bovienii SS 2004, the entomopathogenic symbiont of Steinernema jollieti nematodes. Env Microbiol.More infoDOI: 10.1111/j.1462-2920.2011.02663.x
- Goodrich-Blair, H., Ané, J., Bever, J. D., Bordenstein, S. R., Bright, M., Chaston, J. M., Clay, K., Currie, C. R., Douglas, A. E., Gerardo, N., Harrison, M. J., Ley, R. E., McFall-Ngai, M., Mukherjee, A., Rader, B., Raffa, K. F., Ruby, E. G., Saffo, M. B., Selosse, M., , Sonnenburg, J. L., et al. (2010). Symbiosis research, technology, and education: Proceedings of the 6th International Symbiosis Society Congress held in Madison Wisconsin, USA, August 2009. Symbiosis, 51(1), 1-12.More infoAbstract: Symbiosis, the intimate association between two or more organisms, is a fundamental component of biological systems. Our ability to understand the processes involved in the establishment and function of Symbiosis has critical consequences for the health of humans and the world we live in. For example, a deeper understanding of how legumes and insects have harnessed the nitrogen-fixing capacity of microbes can pave the way toward novel strategies to decrease fertilizer use. Also, using insect models to elucidate links between diet, gut microbiota, and toxin sensitivity not only has implications for biological control strategies, but also will lend insights into similar links in the human gut ecosystem. These types of ideas were presented and discussed at the 6th International Symbiosis Society Congress held in Madison, Wisconsin August, 2009. Over 300 participants from 20 countries attended the 7-day event, which featured cutting-edge symbiosis research from many different perspectives and disciplines. The conference was organized thematically, with oral sessions focused on Evolution, Ecology, Metabolism, the Host-Microbe Interface, Threats to Earth Systems, Symbiosis Models and the Human Microbiome, Viruses and Organelles, and Symbiosis Education. World-renowned scientists, post-doctoral fellows, and students were given the opportunity to describe their most recent discoveries. Session chairs provided overviews of their programs which highlight how the comparative analysis of different systems reveal common trends underlying symbiotic associations, what tools and theory are being developed that may be applied more broadly in symbiosis research, how symbiosis research contributing solutions to global issues such as emerging antibiotic resistance, a need for alternative energy sources, the pursuit of sustainable agriculture and natural resources, and how symbiotic systems are ideal for educating people about the fascinating natural world around us. The following paragraphs provide an overview of the research and discussions that took place during the congress. © 2010 Springer Science+Business Media B.V.
- Lee, M., & Stock, S. P. (2010). A multilocus approach to assessing co-evolutionary relationships between Steinernema spp. (Nematoda: Steinernematidae) and their bacterial symbionts Xenorhabdus spp. (γ-Proteobacteria: Enterobacteriaceae). Systematic Parasitology, 77(1), 1-12.More infoPMID: 20700692;Abstract: Nematodes of the genus Steinernema Travassos, 1927 (Nematoda: Steinernematidae) and their associated bacteria, Xenorhabdus spp. (γ-Proteobacteria), are an emergent model of terrestrial animal-microbe symbiosis. Interest in this association initially arose out of their potential as biocontrol agents against insect pests, but, despite advances in their field application and the growing popularity of this model system, relatively little has been published to uncover the evolutionary facets of this beneficial partnership. This study adds to the body of knowledge regarding nematode-bacteria symbiosis by proposing a possible scenario for their historical association in the form of a cophylogenetic hypothesis. Topological and likelihood based testing methods were employed to reconstruct a history of association between 30 host-symbiont pairs and to gauge the level of similarity between their inferred phylogenetic patterns. © 2010 Springer Science+Business Media B.V.
- Lee, M., Lee, M., Stock, S. P., & Stock, S. P. (2010). A multigene approach for assessing evolutionary relationships of Xenorhabdus spp. (γ-Proteobacteria), the bacterial symbionts of entomopathogenic Steinernema nematodes. Journal of Invertebrate Pathology, 104(2), 67-74.More infoPMID: 20102721;Abstract: Xenorhabdus spp., are gram-negative bacterial symbionts of entomopathogenic nematodes in the genus Steinernema. A specialized and intimate relationship exists between nematode and bacteria, affecting many of their life history traits, such as nutrition, dispersal, host-finding, foraging and defense from biotic and abiotic factors. Xenorhabdus currently comprises more than 20 species isolated from Steinernema spp. with diverse host range, host foraging behavior, reproductive modes and environmental tolerance. Xenorhabdus phylogenies have historically been based on 16s rDNA sequence analyses, and only recently has data from housekeeping genes been employed. The prevalence of lateral gene transfer among bacteria calls for a wider perspective when considering their phylogeny. With the increasing number of Xenorhabdus species and strains, various perspectives need to be considered for investigating the evolutionary history of these nematode bacterial symbionts, In this study, we reconstruct the evolutionary histories of 30 species of Xenorhabdus considering the traditional 16s rDNA gene region as well as the housekeeping genes recA and serC. Datasets were analyzed individually and then combined, using a variety of phylogenetic criteria. © 2010 Elsevier Inc.
- Stock, S. P., Bordenstein, S. R., Odden, J., Oldenburg, D., Reznikoff, W., Werren, J. H., & Selosse, M. (2010). Symbiosis instruction: Considerations from the education workshop at the 6th ISS Congress. Symbiosis, 51(1), 67-73.More infoAbstract: Herein, we summarize presentations on "Symbiosis" instruction given at the Education Workshop held at the 6th International Symbiosis Society Meeting in Madison WI. We convey our teaching experiences and methods in a variety of venues. Information on target audiences, course syllabi, and laboratory skills, utilizing various symbiotic systems are also presented. We hope this review will contribute to further adoption of symbiotic interactions in the classroom as well as the growth of currently developed courses in this field-a specific mission of this and previous International Symbiosis Society meetings. © 2010 Springer Science+Business Media B.V.
- Stock, S., Lee, M., & Stock, S. P. (2010). A multigene approach for assessing evolutionary relationships of Xenorhabdus spp. (gamma-Proteobacteria), the bacterial symbionts of entomopathogenic Steinernema nematodes. Journal of invertebrate pathology, 104(2).More infoXenorhabdus spp., are gram-negative bacterial symbionts of entomopathogenic nematodes in the genus Steinernema. A specialized and intimate relationship exists between nematode and bacteria, affecting many of their life history traits, such as nutrition, dispersal, host-finding, foraging and defense from biotic and abiotic factors. Xenorhabdus currently comprises more than 20 species isolated from Steinernema spp. with diverse host range, host foraging behavior, reproductive modes and environmental tolerance. Xenorhabdus phylogenies have historically been based on 16s rDNA sequence analyses, and only recently has data from housekeeping genes been employed. The prevalence of lateral gene transfer among bacteria calls for a wider perspective when considering their phylogeny. With the increasing number of Xenorhabdus species and strains, various perspectives need to be considered for investigating the evolutionary history of these nematode bacterial symbionts, In this study, we reconstruct the evolutionary histories of 30 species of Xenorhabdus considering the traditional 16s rDNA gene region as well as the housekeeping genes recA and serC. Datasets were analyzed individually and then combined, using a variety of phylogenetic criteria.
- Stock, S., Lee, M., & Stock, S. P. (2010). A multilocus approach to assessing co-evolutionary relationships between Steinernema spp. (Nematoda: Steinernematidae) and their bacterial symbionts Xenorhabdus spp. (gamma-Proteobacteria: Enterobacteriaceae). Systematic parasitology, 77(1).More infoNematodes of the genus Steinernema Travassos, 1927 (Nematoda: Steinernematidae) and their associated bacteria, Xenorhabdus spp. (gamma-Proteobacteria), are an emergent model of terrestrial animal-microbe symbiosis. Interest in this association initially arose out of their potential as biocontrol agents against insect pests, but, despite advances in their field application and the growing popularity of this model system, relatively little has been published to uncover the evolutionary facets of this beneficial partnership. This study adds to the body of knowledge regarding nematode-bacteria symbiosis by proposing a possible scenario for their historical association in the form of a cophylogenetic hypothesis. Topological and likelihood based testing methods were employed to reconstruct a history of association between 30 host-symbiont pairs and to gauge the level of similarity between their inferred phylogenetic patterns.
- Hatting, J., Hatting, J., Stock, S. P., Stock, S. P., Hazir, S., & Hazir, S. (2009). Diversity and distribution of entomopathogenic nematodes (Steinernematidae, Heterorhabditidae) in South Africa. Journal of Invertebrate Pathology, 102(2), 120-128.More infoPMID: 19615373;Abstract: A total of 1506 soil samples from different habitats in seven geographic regions of South Africa were evaluated for the presence of entomopathogenic nematodes (EPN). Nematodes were isolated from 5% of the samples. Among the steinernematids, four Steinernema sp. were recovered including Steinernema khoisanae and three new undescribed species. Although steinernematids were recovered from both humid subtropical and semiarid regions, this family accounted for 80% of EPN recovered from the semiarid climate zones characterised by sandy, acidic soils. Eight isolates of S. khoisanae were recovered from the Western Cape province. One of the new undescribed steinernematids (Steinernema sp. 1) was recovered only from the Free State and KwaZulu-Natal provinces where humid subtropical conditions prevail and soils are generally less acidic with higher clay content. A high level of adaptation, however, was noted with Steinernema sp. 2, which was recovered from a wide range of soil conditions and habitats ranging from semiarid (Western Cape province) to humid subtropical (KwaZulu-Natal province). A third undescribed steinernematid, Steinernema sp. 3, seemed better adapted to heavier soils with more than 80% of isolates recovered from fruit orchards in the Free State province. Heterorhabditis bacteriophora was the only heterorhabditid recovered during this survey. This species was particularly prevalent in four provinces ranging from humid subtropical to semiarid regions. Isolation of EPN directly from insect cadavers included Steinernema sp. 2 and one H. bacteriophora from an unidentified white grub (Scarabaeidae) cadaver (i.e., dual infection) and H. bacteriophora from the black vine weevil, Otiorhynchus sulcatus. © 2009 Elsevier Inc. All rights reserved.
- Lee, M., Sicard, M., Skeie, M., & Stock, S. P. (2009). Steinernema boemarei n. sp. (Nematoda: Steinernematidae), a new entomopathogenic nematode from southern France. Systematic Parasitology, 72(2), 127-141.More infoPMID: 19115086;Abstract: A new entomopathogenic nematode, Steinernema boemarei n. sp., is described from southern France. Morphological, molecular (28S and ITS rDNA sequence data) and cross-hybridisation studies were used for diagnostics and identification purposes. Both molecular and morphological data indicate that the new species belongs to the 'glaseri-group' of Steinernema spp. Key morphological diagnostic traits for S. boemarei n. sp. include the presence of prominent deirids (cervical papillae) on adult males, the morphology of the spicules and gubernaculum, and the arrangement of the 23 genital papillae of the first generation males. Additionally, morphometric traits of the third-stage infective juvenile, including total body length (mean 1,103 μm), tail length (mean 86 μm), location of the excretory pore (mean 91 μm), and D% (mean 63), E% (mean 106) and H% (mean 41) values are definitive. In addition to these morphological characters, analysis of both 28S and ITS rDNA sequences depict this Steinernema species as a distinct and unique entity. © 2008 Springer Science+Business Media B.V.
- Plichta, K. L., Joyce, S. A., Clarke, D., Waterfield, N., & Stock, S. P. (2009). Heterorhabditis gerrardi n. sp. (Nematoda: Heterorhabditidae): The hidden host of Photorhabdus asymbiotica (Enterobacteriaceae: γ-proteobacteria). Journal of Helminthology, 83(4), 309-320.More infoPMID: 19216823;Abstract: A new entomopathogenic nematode species from Australia, Heterorhabditis gerrardi n. sp. (Nematoda: Heterorhabditidae) is described. Morphological and molecular studies together with cross-hybridization tests indicated that this nematode represents a new undescribed species, closely related to members in the indica-group. However, the new species can be distinguished from other species in this genus by a combination of several qualitative and quantitative morphological traits. Key diagnostic features include: body size and excretory pore position of the third-stage infective juveniles; male bursa with a reduction of bursal rays, usually affecting the terminal set of papillae, with symmetrical or asymmetrical loss of one or two pairs; vulva of hermaphrodites more anteriorly located than in other species in the indica-group (V% average: 43), with non-protruding or slightly protruding lips, and longer tail length (average: 106μm). The new species can be further characterized by molecular traits of sequence data from the internal transcribed spacer (ITS) region of ribosomal DNA. Additionally, the bacterial symbiont of this new species, Photorhabdus asymbiotica Kingscliff strain, was phenotypically characterized and compared with other P. asymbiotica strains. The Kingscliff strain revealed many characters not present in other strains of this species. We hypothesize that the newly found traits may contribute to the maintenance of this mutualistic association of the bacterium with its nematode host. Copyright © Cambridge University Press 2009.
- Powers, T. O., Neher, D. A., Mullin, P., Esquivel, A., Giblin-Davis, R., Kanzaki, N., Stock, S. P., Mora, M. M., & Uribe-Lorio, L. (2009). Tropical nematode diversity: Vertical stratification of nematode communities in a Costa Rican humid lowland rainforest. Molecular Ecology, 18(5), 985-996.More infoPMID: 19207247;Abstract: Comparisons of nematode communities among ecosystems have indicated that, unlike many organisms, nematode communities have less diversity in the tropics than in temperate ecosystems. There are, however, few studies of tropical nematode diversity on which to base conclusions of global patterns of diversity. This study reports an attempt to estimate nematode diversity in the lowland tropical rainforest of La Selva Biological Research Station in Costa Rica. We suggest one reason that previous estimates of tropical nematode diversity were low is because habitats above the mineral soil are seldom sampled. As much as 62% of the overall genetic diversity, measured by an 18S ribosomal barcode, existed in litter and understorey habitats and not in soil. A maximum-likelihood tree of barcodes from 360 individual nematodes indicated most major terrestrial nematode lineages were represented in the samples. Estimated 'species' richness ranged from 464 to 502 within the four 40 × 40 m plots. Directed sampling of insects and their associated nematodes produced a second set of barcodes that were not recovered by habitat sampling, yet may constitute a major class of tropical nematode diversity. While the generation of novel nematode barcodes proved relatively easy, their identity remains obscure due to deficiencies in existing taxonomic databases. Specimens of Criconematina, a monophyletic group of soil-dwelling plant-parasitic nematodes were examined in detail to assess the steps necessary for associating barcodes with nominal species. Our results highlight the difficulties associated with studying poorly understood organisms in an understudied ecosystem using a destructive (i.e. barcode) sampling method. © 2009 Blackwell Publishing Ltd.
- Stock, S. P. (2009). Molecular approaches and the taxonomy of insect-parasitic and pathogenic nematodes. Insect Pathogens: Molecular Approaches and Techniques, 71-100.
- Stock, S. P., Stock, S. P., Rivera-Orduño, B., Rivera-Orduño, B., Flores-Lara, Y., & Flores-Lara, Y. (2009). Heterorhabditis sonorensis n. sp. (Nematoda: Heterorhabditidae), a natural pathogen of the seasonal cicada Diceroprocta ornea (Walker) (Homoptera: Cicadidae) in the Sonoran desert. Journal of Invertebrate Pathology, 100(3), 175-184.More infoPMID: 19114047;Abstract: A new Heterorhabditis species was isolated from nymphal stages of the seasonal cicada Diceroprocta ornea (Walker) in an asparagus field in the state of Sonora, Mexico. Concomitantly, another isolate of the same nematode species was also collected from an oak woodland habitat in the Chiricahua mountain range in southeastern Arizona. Morphological and molecular studies together with cross-hybridization tests indicate these two isolates are conspecific and represent a new undescribed Heterorhabditis sp. This new species is distinguished from other species in this genus by a combination of several qualitative and quantitative morphological traits. Key diagnostic features include: presence of a pronounced post-anal swelling in the hermaphrodite; male with nine pairs of bursal rays, with pairs 4 and 7 bent outwards and one pair of papillae placed on the cloacal opening, value of D% (average: 79); infective juveniles with a well developed cuticular tooth, long tail (average: 105 μm) and values of D% (average: 90) and E% (average: 99). In addition to these diagnostic characters, cross-hybridization tests between the new species with H. bacteriophora and H. mexicana yielded no fertile progeny. Comparison of ITS rDNA sequences with other available sequences of described species depicted the two isolates as a new species. Phylogenetic analysis of these sequence data placed H. sonorensis n. sp. as a member of the indica-group. © 2008 Elsevier Inc. All rights reserved.
- Stock, S. P., Vanderberg, J., Boemare, N., & Glazer, I. (2009). Insect pathogens: Molecular approaches and techniques. Insect Pathogens: Molecular Approaches and Techniques, 1-417.More infoAbstract: Investigation of insect pathogens is vital to the understanding of biocontrol and insect management within an ecosystem. Faster and more accurate methods of identification and diagnosis have become possible with the implementation of molecular techniques. Advances in genomics and genetic engineering make this manual the most up to date handbook on insect pathogens, with the latest information on methods used to unravel the genomes of pathogens. The book is divided into four sections covering: Identification and Diagnostics, Evolutionary Relationships and Population Genetics, Genomics, and Genetic Engineering. It is essential reading for those studying and researching at the forefront of molecular science and biological management. © CAB International 2009. All rights reserved.
- Stock, S. P., Vanderberg, J., Boemare, N., & Glazer, I. (2009). Preface. Insect Pathogens: Molecular Approaches and Techniques, xiii-xiv.
- Stock, S., Lee, M., Sicard, M., Skeie, M., & Stock, S. P. (2009). Steinernema boemarei n. sp. (Nematoda: Steinernematidae), a new entomopathogenic nematode from southern France. Systematic parasitology, 72(2).More infoA new entomopathogenic nematode, Steinernema boemarei n. sp., is described from southern France. Morphological, molecular (28S and ITS rDNA sequence data) and cross-hybridisation studies were used for diagnostics and identification purposes. Both molecular and morphological data indicate that the new species belongs to the 'glaseri-group' of Steinernema spp. Key morphological diagnostic traits for S. boemarei n. sp. include the presence of prominent deirids (cervical papillae) on adult males, the morphology of the spicules and gubernaculum, and the arrangement of the 23 genital papillae of the first generation males. Additionally, morphometric traits of the third-stage infective juvenile, including total body length (mean 1,103 micron), tail length (mean 86 micron), location of the excretory pore (mean 91 micron), and D% (mean 63), E% (mean 106) and H% (mean 41) values are definitive. In addition to these morphological characters, analysis of both 28S and ITS rDNA sequences depict this Steinernema species as a distinct and unique entity.
- Emelianoff, V., Emelianoff, V., Brun, N. L., Brun, N. L., Pagès, S., Pagès, S., Stock, S. P., Stock, S. P., Tailliez, P., Tailliez, P., Moulia, C., Moulia, C., Sicard, M., & Sicard, M. (2008). Isolation and identification of entomopathogenic nematodes and their symbiotic bacteria from Hérault and Gard (Southern France). Journal of Invertebrate Pathology, 98(2), 211-217.More infoPMID: 18353356;Abstract: Isolation and identification of native nematode-bacterial associations in the field are necessary for successful control of endemic pests in a particular location. No study has yet been undertaken to recover and identify EPN in metropolitan France. In the present paper, we provide results of a survey of EPN and their symbiotic bacteria conducted in Hérault and Gard regions in Southern France. Molecular characterization of isolated nematodes depicted three different Steinernema species and one Heterorhabditis species, H. bacteriophora. Steinernema species recovered were identified as: S. feltiae and S. affine and an undescribed species. Xenorhabdus symbionts were identified as X. bovienii for both S. feltiae and S. affine. Phylogenetic analysis placed the new undescribed Steinernema sp. as closely related to S. arenarium but divergent enough to postulate that it belongs to a new species within the "glaseri-group". The Xenorhabdus symbiont from this Steinernema sp. was identified as X. kozodoii. All Heterorhabditis isolates recovered were diagnosed as H. bacteriophora and their bacterial symbionts were identified as Photorhabdus luminescens. Molecular characterization of these nematodes enabled the distinction of two different H. bacteriophora strains. Bacterial symbiontic strains of these two H. bacteriophora strains were identified as P. luminescens ssp. kayaii and P. luminescens ssp. laumondii. © 2008 Elsevier Inc. All rights reserved.
- López-Núñez, J. C., Plichta, K., Góngora-Botero, C. E., & Stock, P. S. (2008). A new entomopathogenic nematode, Steinernema colombiense n. sp. (Nematoda: Steinernematidae), from Colombia. Nematology, 10(4), 561-574.More infoAbstract: A new entomopathogenic nematode, Steinernema colombiense n. sp., is described from Colombia. Morphological, molecular (28S and ITS rDNA sequence data) and cross-hybridisation studies were used for diagnostics and identification purposes. In addition, 28S and ITS rDNA sequence data were used to assess evolutionary relationships of the new species with other Steinernema spp. Morphological diagnostic features for S. colombiense n. sp. include morphometric features of the third-stage infective juvenile, including body length of 636 (549-732) μm, narrow body diam. (31 (22-36) μm), position of the excretory pore (35 (31-40) μm), tail length (41 (32-53) μm), D% = 29 (25-33) and E% = 205 (138-284). In addition, males of first and second generations are characterised by the morphology of the spicules and gubernaculum, the number and arrangement of the genital papillae and the excretory pore position (at 67 (56-76) and 54 (46-63) μm, for first and second generations, respectively). In addition to these traits, 28S and ITS rDNA sequences analyses both showed this species to be a distinct and unique entity. © 2008 Brill Academic Publishers.
- Stock, S. P., & Blair, H. G. (2008). Entomopathogenic nematodes and their bacterial symbionts: The inside out of a mutualistic association. Symbiosis, 46(2), 65-75.More infoAbstract: Entomopathogenic nematodes Steinernema and Heterorhabditis spp. (Nematoda: Steinernematidae, Heterorhabditidae) and their bacterial symbiont bacteria Xenorhabdus and Photorhabdus spp (Gram-negative Enterobacteriaceae) represent an emerging model of terrestrial animal-microbe symbiotic relationships. Xenorhabdus and Photorhabdus spp. are harbored as symbionts in the intestine of the only free-living stage of the nematodes, also known as the infective juvenile or 3rd stage infective juvenile. The bacterium-nematode pair is pathogenic for a wide range of insects and has successfully been implemented in biological control and integrated pest management programs worldwide. Moreover, realization of the practical use of these nematodes has spurred developments across a far broader scientific front. Recent years have seen an intensive worldwide search for fresh genetic materials resulting in an exponential growth of described new species and the discovery of thousands of new isolates worldwide. These nematodes and their bacterial symbionts are now considered a tractable model system that is amenable to study physiological, chemical, structural and developmental aspects of beneficial symbiotic associations. We herein provide an overview of the research done in relation to the study of the symbiotic interactions between Steinernema and Heterorhabditis nematodes and their bacterial symbionts. ©2008 Balaban.
- Stock, S. P., & Blair, H. G. (2008). Nematode-bacterium symbioses: Crossing kingdom and disciplinary boundaries. Symbiosis, 46(2), 61-64.More infoAbstract: One of the most common eukaryote-prokaryote interactions is that between nematodes and bacteria. The range of associations between nematodes and bacteria is incredibly broad, ranging from fortuitous to obligate and from beneficial to pathogenic and occurring in all possible habitats. Numerous researchers worldwide are studying associations between these two groups of organisms, but these scientists occupy many different disciplines, and often do not interact. Not surprisingly these researchers come from diverse backgrounds in medicine and veterinary science, entomology, plant biology, genetics etc., yet to date no common coherent ground exists connecting the science being done in nematode-bacterial interactions despite the fact that advances in each will undoubtedly inform the others. Furthermore, a comparative approach between species pairs, or between different research angles has the power to reveal common underlying themes of nematode-bacterium associations as well as fundamental questions or research topics of symbiosis. For the first time, researchers working on different nematode-bacterium systems were gathered under a unifying theme, a workshop on 'Nematode-Bacterium Symbioses' that was held at the University of Arizona, Tucson, Arizona from April 21 to 23, 2007. The goals of this workshop were threefold: 1) Foster interdisciplinary collaborations among scientists; 2) Break down barriers among researchers studying different taxonomic groups of nematode-microbe associations; and 3) Encourage scientists engaged in basic and applied research to explore how cross-talk and networking can enhance and advance science in this field. Keynote speakers presented on a broad range of taxa and topics pertaining to microbe-nematode interactions, including ecto- and endosymbiosis, beneficial symbioses, multitrophic interactions, pathogenesis, host recognition, colonization processes, genetics and genomics. ©2008 Balaban.
- Stock, S. P., Stock, S. P., Banna, L. A., Banna, L. A., Darwish, R., Darwish, R., Katbeh, A., & Katbeh, A. (2008). Diversity and distribution of entomopathogenic nematodes (Nematoda: Steinernematidae, Heterorhabditidae) and their bacterial symbionts (γ-Proteobacteria: Enterobacteriaceae) in Jordan. Journal of Invertebrate Pathology, 98(2), 228-234.More infoPMID: 18280494;Abstract: Until now, only a few systematic surveys of entomopathogenic nematodes (EPN) have been conducted in Middle Eastern countries. Many of the recovered EPN species in this region have shown to own distinctive qualities that enable their survival in unique environments, such as high temperatures and low moisture levels tolerance. These new species and strains, with unique environmental tolerances, are more suitable for their consideration in pest management programs in xerophytic regions. With this background in mind, we recently conducted a survey of EPN in Jordan. This study records for the first time the diversity and distribution of these nematodes and their bacterial symbionts in this country. Jordan's three geographic regions: (1) the highlands, (2) Jordan valley and (3) the desert region were sampled. Within each region, natural habitats and agricultural regions characteristic to each region were considered for sampling purposes. Four EPN species including three Steinernema and one Heterorhabditis were recovered. Nematodes were identified using a combination of molecular markers and classic morphological diagnostic tools. Bacterial symbionts were identified by analysis of 16S rRNA sequences. Abiotic characteristics such as soil type, soil pH, and elevation were also recorded. We herein report the diversity of EPN species in Jordan and discuss their potential in Biocontrol and IPM programs for this country. © 2008 Elsevier Inc. All rights reserved.
- Flores-Lara, Y., Flores-Lara, Y., Renneckar, D., Renneckar, D., Forst, S., Forst, S., Goodrich-Blair, H., Goodrich-Blair, H., Stock, P., & Stock, P. (2007). Influence of nematode age and culture conditions on morphological and physiological parameters in the bacterial vesicle of Steinernema carpocapsae (Nematoda: Steinernematidae). Journal of Invertebrate Pathology, 95(2), 110-118.More infoPMID: 17376477;Abstract: Steinernema spp. third-stage infective juveniles (IJs) play a key role in the symbiotic partnership between these entomopathogenic nematodes and Xenorhabdus bacteria. Recent studies suggest that Steinernema carpocapsae IJs contribute to the nutrition and growth of their symbionts in the colonization site (vesicle) [Martens, E.C. and Goodrich-Blair, H., 2005. The S. carpocapsae intestinal vesicle contains a sub-cellular structure with which Xenorhabdus nematophila associates during colonization initiation. Cellular Microbiol. 7, 1723-1735.]. However, the morphological and physiological interactions between Xenorhabdus symbionts and Steinernema IJs are not understood in depth. This study was undertaken to assess the influence of culture conditions and IJ age on the structure, nutrition, and symbiont load (colonization level) of S. carpocapsae vesicles. Our observations indicate the vesicles of axenic IJs are shorter and wider than those of colonized IJs. Moreover, as colonized IJs age the vesicle becomes shorter and narrower and bacterial load declines. The colonization proficiency of several bacterial metabolic mutants was compared between two cultivation conditions: in vitro on lipid agar and in vivo in Galleria mellonella insects. Colonization defects were generally less severe in IJs cultivated in vivo versus those cultivated in vitro. However, IJs from both cultivation conditions exhibited similar declining bacterial load over time. These results suggest that although the vesicle forms in the absence of bacteria, the presence of symbionts within the vesicle may influence its fine structure. Moreover, these studies provide further evidence in support of the concept that the conditions under which steinernematid nematodes are cultivated and stored affect the nutritive content of the vesicle and the bacterial load, and therefore have an impact on the quality of the nematodes for their application as biological control agents. © 2007 Elsevier Inc. All rights reserved.
- López-Núñez, J. C., Cano, L., Góngora-B, C. E., & Stock, S. P. (2007). Diversity and evolutionary relationships of entomopathogenic nematodes (Steinernematidae and Heterorhabditidae) from the Central Andean region of Colombia. Nematology, 9(3), 333-341.More infoAbstract: A survey of entomopathogenic nematodes (EPN) was conducted in the Central Andean region of Colombia. Out of a total of 945 soil samples, 28 (3%) were positive for entomopathogenic nematodes. Of them, 26 samples (92.8%) contained Steinernema and two (7.2%) harboured Heterorhabditis isolates. Characterisation of the recovered isolates was done by analysis of rDNA sequences. The large subunit of rDNA (28S) was considered for diagnosis of Steinernema species whereas the internal transcribed spacer region (ITS) of rDNA was used to identify Heterorhabditis isolates recovered in this study. Five Steinernema spp. were isolated and identified as S. websteri and four new, undescribed species. Steinernema websteri was isolated from two sites: Naranjal and Paraguaicito stations. At Naranjal, this species was recovered from a coffee plantation and a forest habitat surrounding these plantations. At Paraguaicito, the same species was recovered from a coffee-guamo habitat. Steinernema sp. 1 was collected from nogal cafetero (Cordia allaidora) groves and forest habitats at Paraguaicito station. Steinernema sp. 2 was found in coffee-guamo habitats both at Naranjal and Paraguaicito stations. Steinernema sp. 3 was the only EPN species recovered at Santa Barbara station in association with plantain. This species was also found at La Catalina station in association with forest habitats and also from soil samples taken from a landscaped area with Heliconia sp. and grass cover (Arachis pintoi) at Cenicafé La Granja station and a coffee-guamo habitat at Naranjal station. Steinernema sp. 4 was found at La Catalina in a forest habitat, also associated with Steinernema sp. 3 (isolate JCL002) and Heterorhabditis sp. 1 (isolate JCL 003). The Heterorhabditis isolates were identified as two undescribed Heterorhabditis spp. Heterorhabditis sp. 1 (isolate JCL003) was recovered at La Catalina station associated with a forest habitat. Heterorhabditis sp. 2 (isolate JCL040) was collected from a coffee-guamo habitat at Naranjal station. Although limited to one geographic region, this study suggests entomopathogenic nematodes in Colombia are quite diverse and are perhaps widely distributed in this country. A more intensive survey covering all geographic regions is currently underway. © 2007 Brill Academic Publishers.
- Simard, L., Bélair, G., Stock, S. P., Mauléon, H., & Dionne, J. (2007). Natural occurrence of entomopathogenic nematodes (Rhabditida: Steinernematidae) on golf courses in eastern Canada. Nematology, 9(3), 325-332.More infoAbstract: A survey of entomopathogenic nematodes from 38 golf courses was conducted in different climatic areas of Ontario and Québec provinces, Canada, during autumn 2002 and 2003. Soil samples were collected on golf course greens, fairways and roughs. Entomopathogenic nematodes were isolated from soil using wax moth (Galleria mellonella) and carrot weevil (Listronotus oregonensis) larvae as bait. Of the 436 samples (218 sites), 11 contained entomopathogenic nematodes for this study. All entomopathogenic nematode-positive samples were isolated from roughs. Isolates were characterised using DNA satellite probes and 28S rDNA sequence data. Both methods confirmed the identities of nematode isolates as Steinernema carpocapsae, S. feltiae and S. kraussei. © 2007 Brill Academic Publishers.
- Snyder, H., Stock, S. P., Kim, S., Flores-Lara, Y., & Forst, S. (2007). New insights into the colonization and release processes of Xenorhabdus nematophila and the morphology and ultrastructure of the bacterial receptacle of its nematode host, Steinernema carpocapsae. Applied and Environmental Microbiology, 73(16), 5338-5346.More infoPMID: 17526783;PMCID: PMC1951000;Abstract: We present results from epifluorescence, differential interference contrast, and transmission electron microscopy showing that Xenorhabdus nematophila colonizes a receptacle in the anterior intestine of the infective juvenile (IJ) stage of Steinernema carpocapsae. This region is connected to the esophagus at the esophagointestinal junction. The process by which X. nematophila leaves this bacterial receptacle had not been analyzed previously. In this study we monitored the movement of green fluorescent protein-labeled bacteria during the release process. Our observations revealed that Xenorhabdus colonizes the distal region of the receptacle and that exposure to insect hemolymph stimulated forward movement of the bacteria to the esophagointestinal junction. Continued exposure to hemolymph caused a narrow passage in the distal receptacle to widen, allowing movement of Xenorhabdus down the intestine and out the anus. Efficient release of both the wild type and a nonmotile strain was evident in most of the IJs incubated in hemolymph, whereas only a few IJs incubated in nutrient-rich broth released bacterial cells. Incubation of IJs in hemolymph treated with agents that induce nematode paralysis dramatically inhibited the release process. These results suggest that bacterial motility is not required for movement out of the distal region of the receptacle and that hemolymph-induced esophageal pumping provides a force for the release of X. nematophila out of the receptacle and into the intestinal lumen. Copyright © 2007, American Society for Microbiology. All Rights Reserved.
- Stock, S., Flores-Lara, Y., Renneckar, D., Forst, S., Goodrich-Blair, H., & Stock, S. P. (2007). Influence of nematode age and culture conditions on morphological and physiological parameters in the bacterial vesicle of Steinernema carpocapsae (Nematoda: Steinernematidae). Journal of invertebrate pathology, 95(2).More infoSteinernema spp. third-stage infective juveniles (IJs) play a key role in the symbiotic partnership between these entomopathogenic nematodes and Xenorhabdus bacteria. Recent studies suggest that Steinernema carpocapsae IJs contribute to the nutrition and growth of their symbionts in the colonization site (vesicle) [Martens, E.C. and Goodrich-Blair, H., 2005. The S. carpocapsae intestinal vesicle contains a sub-cellular structure with which Xenorhabdus nematophila associates during colonization initiation. Cellular Microbiol. 7, 1723-1735.]. However, the morphological and physiological interactions between Xenorhabdus symbionts and Steinernema IJs are not understood in depth. This study was undertaken to assess the influence of culture conditions and IJ age on the structure, nutrition, and symbiont load (colonization level) of S. carpocapsae vesicles. Our observations indicate the vesicles of axenic IJs are shorter and wider than those of colonized IJs. Moreover, as colonized IJs age the vesicle becomes shorter and narrower and bacterial load declines. The colonization proficiency of several bacterial metabolic mutants was compared between two cultivation conditions: in vitro on lipid agar and in vivo in Galleria mellonella insects. Colonization defects were generally less severe in IJs cultivated in vivo versus those cultivated in vitro. However, IJs from both cultivation conditions exhibited similar declining bacterial load over time. These results suggest that although the vesicle forms in the absence of bacteria, the presence of symbionts within the vesicle may influence its fine structure. Moreover, these studies provide further evidence in support of the concept that the conditions under which steinernematid nematodes are cultivated and stored affect the nutritive content of the vesicle and the bacterial load, and therefore have an impact on the quality of the nematodes for their application as biological control agents.
- Uribe-Lorío, L., Mora, M., & Stock, S. P. (2007). Steinernema costaricense n. sp. and S. puntauvense n. sp. (Rhabditida: Steinernematidae), two new entomopathogenic nematodes from Costa Rica. Systematic Parasitology, 68(3), 167-182.More infoPMID: 17896186;Abstract: Steinernema costaricense n. sp. and S. puntauvense n. sp. were recovered during a survey for native entomopathogenic nematodes in Costa Rica. Morphological data, molecular (28S rDNA sequence data) studies and cross-hybridisation tests were used for diagnostic and identification purposes. Additionally, 28S rDNA sequence data were used to assess the evolutionary relationships of the new species with other Steinernema spp. Morphological diagnostic features for S. costaricense n. sp. include: the body size of the infective juvenile (av. 1,696); the presence of protruding 'horn-like' cephalic papillae; the position of the excretory pore in the infective juvenile (av. 77 μm) and the first generation male (av. 117 μm); the D% value of the infective juvenile (av. 53) and the first generation male (av. 56); the E% value of the infective juvenile (av. 85); and the morphology of the spicules and gubernaculum of the first generation male. Diagnostic traits for S. puntauvense n. sp. are: the position of the excretory pore in the infective juveniles (av. 25 μm); the shape and size of the spicules and gubernaculum of the first generation male; and the shape of the tail of the first generation female. In addition to these traits, 28S rDNA sequences analysis and hybridisation tests showed that both new Steinernema species are distinct and unique entities. © 2007 Springer Science+Business Media B.V.
- Adams, B. J., Fodor, A., Koppenhöfer, H. S., Stackebrandt, E., Stock, S. P., & Klein, M. G. (2006). Biodiversity and systematics of nematode-bacterium entomopathogens. Biological Control, 37(1), 32-49.More infoAbstract: Nematodes are one of the most abundant animals on earth, and bacteria comprise the most biologically and phylogenetically diverse domains of organisms. On at least two separate occasions a soil dwelling nematode and a bacterium have entered into a mutualistic, insecticidal association. From such origins arose two distinct lineages of nematode-bacterium entomopathogens, Steinernema-Xenorhabdus and Heterorhabditis-Photorhabdus. Herein, we present a summary and discussion of the known evolutionary diversity and systematics of these two groups relative to other nematodes and bacteria, and their shared evolutionary history. © 2005 Elsevier Inc. All rights reserved.
- Adams, B. J., Fodor, A., Koppenhöfer, H. S., Stackebrandt, E., Stock, S. P., & Klein, M. G. (2006). Reprint of "Biodiversity and systematics of nematode-bacterium entomopathogens" [Biol. Control 37 (2006) 32-49]. Biological Control, 38(1), 4-21.More infoAbstract: Nematodes are one of the most abundant animals on earth, and bacteria comprise the most biologically and phylogenetically diverse domains of organisms. On at least two separate occasions a soil dwelling nematode and a bacterium have entered into a mutualistic, insecticidal association. From such origins arose two distinct lineages of nematode-bacterium entomopathogens, Steinernema-Xenorhabdus and Heterorhabditis-Photorhabdus. Herein, we present a summary and discussion of the known evolutionary diversity and systematics of these two groups relative to other nematodes and bacteria, and their shared evolutionary history. © 2005 Elsevier Inc. All rights reserved.
- Nadler, S. A., Bolotin, E., & Stock, S. P. (2006). Phylogenetic relationships of Steinernema Travassos, 1927 (Nematoda: Cephalobina: Steinernematidae) based on nuclear, mitochondrial and morphological data. Systematic Parasitology, 63(3), 161-181.More infoPMID: 16541298;Abstract: Entomopathogenic nematodes of the genus Steinernema are lethal parasites of insects that are used as biological control agents of several lepidopteran, dipteran and coleopteran pests. Phylogenetic relationships among 25 Steinernema species were estimated using nucleotide sequences from three genes and 22 morphological characters. Parsimony analysis of 28S (LSU) sequences yielded a well-resolved phylogenetic hypothesis with reliable bootstrap support for 13 clades. Parsimony analysis of mitochondrial DNA sequences (12S rDNA and cox 1 genes) yielded phylogenetic trees with a lower consistency index than for LSU sequences, and with fewer reliably supported clades. Combined phylogenetic analysis of the 3-gene dataset by parsimony and Bayesian methods yielded well-resolved and highly similar trees. Bayesian posterior probabilities were high for most clades; bootstrap (parsimony) support was reliable for approximately half of the internal nodes. Parsimony analysis of the morphological dataset yielded a poorly resolved tree, whereas total evidence analysis (molecular plus morphological data) yielded a phylogenetic hypothesis consistent with, but less resolved than trees inferred from combined molecular data. Parsimony mapping of morphological characters on the 3-gene trees showed that most structural features of steinernematids are highly homoplastic. The distribution of nematode foraging strategies on these trees predicts that S. hermaphroditum, S. diaprepesi and S. longicaudum (US isolate) have cruise forager behaviours. © Springer 2006.
- Nadler, S. A., Ley, P. D., Mundo-Ocampo, M., Smythe, A. B., Stock, S. P., Bumbarger, D., Adams, B. J., Tandingan, I., Holovachov, O., & Baldwin, J. G. (2006). Phylogeny of Cephalobina (Nematoda): Molecular evidence for recurrent evolution of probolae and incongruence with traditional classifications. Molecular Phylogenetics and Evolution, 40(3), 696-711.More infoPMID: 16750400;Abstract: Nematodes of the suborder Cephalobina include an ecologically and morphologically diverse array of species that range from soil-dwelling microbivores to parasites of vertebrates and invertebrates. Despite a long history of study, certain of these microbivores (Cephaloboidea) present some of the most intractable problems in nematode systematics; the lack of an evolutionary framework for these taxa has prevented the identification of natural groups and inhibited understanding of soil biodiversity and nematode ecology. Phylogenetic analyses of ribosomal (LSU) sequence data from 53 taxa revealed strong support for monophyly of taxa representing the Cephaloboidea, but do not support the monophyly of most genera within this superfamily. Historically these genera have primarily been recognized based on variation in labial morphology, but molecular phylogenies show the same general labial (probolae) morphotype often results from recurrent similarity, a result consistent with the phenotypic plasticity of probolae previously observed for some species in ecological time. Phylogenetic analyses of LSU rDNA also recovered strong support for some other groups of cephalobs, including taxa representing most (but not all) Panagrolaimoidea. In addition to revealing homoplasy of probolae, molecular trees also imply other unexpected patterns of character evolution or polarity, including recurrent similarity of offset spermatheca presence, and representation of complex probolae as the ancestral condition within Cephaloboidea. For Cephalobidae, molecular trees do not support traditional genera as natural groups, but it remains untested if deconstructing probolae morphotypes or other structural features into finer component characters may reveal homologies that help delimit evolutionary lineages. © 2006 Elsevier Inc. All rights reserved.
- Stock, S. P., & Nadler, S. A. (2006). Morphological and molecular characterisation of Panagrellus spp. (Cephalobina: Panagrolaimidae): Taxonomic status and phylogenetic relationships. Nematology, 8(6), 921-938.More infoAbstract: The genus Panagrellus currently comprises 12 known species. These nematodes have a worldwide distribution and have been found in a variety of habitats such as slime flux, thermal springs, insect frass and spoiled cider. Diagnosis of Panagrellus species is rather problematic since few morphological features can be used to discriminate between species and the original publications do not indicate the number of specimens measured and lack standard descriptions of variance. In this study we review the taxonomic status of several species from this genus combining classical morphological data and molecular sequences. Eleven live isolates and fixed material from currently available type specimens representing six Panagrellus species were included. Morphological analysis included the examination of qualitative and quantitative characters of males and females. The taxonomic utility of morphometric data was evaluated by means of multivariate statistics (principal component and canonical discriminant analyses). Phylogenetic inference was based on analysis of nucleotide sequences from the LSU rDNA gene and morphological characters. Parsimony tree topologies inferred from nucleotide datasets strongly supported monophyly of the P. dubius isolates, but not the P. redivivus isolates. Phylogenetic interpretation of these rDNA sequence data suggests that both the P. redivivus and P. dubius isolates each include more than a single species. Only two of the 15 morphological characters evaluated were variable within the ingroup taxa. A long spicule bifurcation length maps on the combined evidence trees as a putative synapmorphy for P. dubius, whereas male D% was homoplastic within isolates of that species. The diagnosis of the genus Panagrellus is emended. © 2006 Koninklijke Brill NV.
- Stock, S. P., Stock, S. P., Gress, J. C., & Gress, J. C. (2006). Diversity and phylogenetic relationships of entomopathogenic nematodes (Steinernematidae and Heterorhabditidae) from the Sky Islands of southern Arizona. Journal of Invertebrate Pathology, 92(2), 66-72.More infoPMID: 16554068;Abstract: A survey for entomopathogenic nematodes was conducted in oak-juniper woodlands of four mountain ranges (Santa Rita, Santa Catalina, Pinaleño, and Chiricahuas), in southeastern Arizona. From a total of 120 soil samples, 23.3% were EPN-positive. Of them 78.5% were positive for Steinernema spp. and 21.5% were positive for Heterorhabditis spp. An integrated approach, combining both traditional (morphological) and molecular methods, was used for examining the diversity of species of these entomopathogenic nematodes. Two named-species S. oregonense and S. riobrave are reported for the first time in Arizona, expanding their currently known geographic range. In addition to this, three undescribed Steinernema and three Heterorhabditis spp. were recovered. Insular evolution, in part, could account for the geographic distribution of entomopathogenic nematodes in Arizona. © 2006 Elsevier Inc. All rights reserved.
- Stock, S. P. (2005). Nematodes and bacteria for insect control. Industrial Bioprocessing, 27(4), 5-6.More infoAbstract: An ongoing study at University of Arizona is searching habitats for nematodes that are potential insect pathogens. A native species for pest control trials in iceberg lettuce and citrus is being searched. Entomopathogenic nematodes are being employed to antagonize the citrus nematode and other plant-parasitic nematodes and to disrupt their life cycle and their infection into the citrus roots. Both commercially available nematode products and isolates of nematodes collected locally are being used.
- Stock, S. P., & Hunt, D. J. (2005). Morphology and systematics of nematodes used in biocontrol. Nematodes as Biocontrol Agent, 3-43.
- Stock, S. P., & Stock, S. P. (2005). Insect-parasitic nematodes: From lab curiosities to model organisms. Journal of Invertebrate Pathology, 89(1), 57-66.More infoPMID: 16039306;Abstract: Interest in studying insect-parasitic nematodes was originally focused on their potential as biological control agents of insects and other arthropod pests. Now, after 30 years of intense basic and applied research, realization of the practical use of insect-parasitic nematodes, particularly of entomopathogenic nematodes and their symbiotic bacteria, has spurred developments across a far broader scientific front. We are now entering a new era of discovery in which tools of molecular genetics are being increasingly used to address a range of biological questions. The knowledge gained from these efforts will directly benefit the practical application of insect-parasitic nematodes as more effective biopesticides. Moreover, these studies will advance these nematodes as unique and intrinsically interesting biological model systems not only for basic research but also in applied fields such as plant health, human medicine, pharmaceutical bioprospecting, and genetic engineering. In this review, the past and current state of insect-parasitic nematode research is summarized. Future research priorities and goals are identified and discussed. © 2005 Elsevier Inc. All rights reserved.
- Stock, S. P., Caicedo, A. M., & Calatayud, P. A. (2005). Rhabditis (Oscheius) colombiana n. sp. (Nematoda: Rhabditidae), a necromenic associate of the subterranean burrower bug Cyrtomenus bergi (Hemiptera: Cydnidae) from the Cauca Valley, Colombia. Nematology, 7(3), 363-373.More infoAbstract: Rhabditis (Oscheius) colombiana n. sp. is described as a necromenic associate of the burrower bug Cyrtomenus bergi (Hemiptera: Cydnidae) collected in the Cauca Valley, Colombia. The new species resembles others of the insectivora-group, viz, Rhabditis (O.) insectivora Körner, 1954 and Rhabditis (O.) lucianii Maupas, 1919, in a number of morphological and life history traits, but can be separated by a combination of morphological and morphometric characters. The most distinctive morphological features that separate R. (O.) colombiana n. sp. from these two Rhabditis species are the total size of both males and females, which are much shorter and slimmer in the new species; the size of the male spicules and the values of ratios b and c. Additionally, molecular data (18S rDNA sequences) and phylogenetic analyses demonstrated the distinctiveness of this species when compared to a number of other Rhabditis (Oscheius) species. © Koninklijke Brill NV, 2005.
- Stock, S., & Stock, S. P. (2005). Insect-parasitic nematodes: from lab curiosities to model organisms. Journal of invertebrate pathology, 89(1).More infoInterest in studying insect-parasitic nematodes was originally focused on their potential as biological control agents of insects and other arthropod pests. Now, after 30 years of intense basic and applied research, realization of the practical use of insect-parasitic nematodes, particularly of entomopathogenic nematodes and their symbiotic bacteria, has spurred developments across a far broader scientific front. We are now entering a new era of discovery in which tools of molecular genetics are being increasingly used to address a range of biological questions. The knowledge gained from these efforts will directly benefit the practical application of insect-parasitic nematodes as more effective biopesticides. Moreover, these studies will advance these nematodes as unique and intrinsically interesting biological model systems not only for basic research but also in applied fields such as plant health, human medicine, pharmaceutical bioprospecting, and genetic engineering. In this review, the past and current state of insect-parasitic nematode research is summarized. Future research priorities and goals are identified and discussed.
- Uribe-Lorío, L., Uribe-Lorío, L., Mora, M., Mora, M., Stock, S. P., & Stock, S. P. (2005). First record of entomopathogenic nematodes (Steinernematidae and Heterorhabditidae) in Costa Rica. Journal of Invertebrate Pathology, 88(3), 226-231.More infoPMID: 15955341;Abstract: A survey of entomopathogenic nematodes was conducted in the north Pacific (Guanacaste Conservation Area) and southeast Caribbean (Gandoca-Manzanillo Natural Refuge) regions of Costa Rica. Out of a total of 41 soil samples, 5 were positive for entomopathogenic nematodes (20.5%), with 3 (12.3%) containing Steinernema and 2 (8.2%) Heterorhabditis isolates. Morphological and molecular studies were undertaken to characterize these isolates. The Heterorhabditis isolates were identified as Heterorhabditis indica and the three Steinernema isolates were identified as two new undescribed species. H. indica was recovered from a coastal dry forest. Steinernema n. sp. 1 was isolated from a rainforest valley, between volcanoes. Steinernema sp. n. 2 was isolated from sand dunes in the Caribbean Coast (Punta Uva) near the rainforest strip along the coast. Although limited to two geographic regions, this study suggests entomopathogenic nematodes may be diverse and perhaps widely distributed in Costa Rica. A more intensive survey, covering all geographic regions is currently undergoing. © 2005 Elsevier Inc. All rights reserved.
- Stock, S. P., Griffin, C. T., & Chaerani, R. (2004). Morphological and molecular characterisation of Steinernema hermaphroditum n. sp. (Nematoda: Steinernematidae), an entomopathogenic nematode from Indonesia, and its phylogenetic relationships with other members of the genus. Nematology, 6(3), 401-412.More infoAbstract: Steinernema hermaphroditum n. sp., a new entomopathogenic nematode isolated from soil samples in the Moluccan islands, Indonesia, is described. Morphological observations as well as biological evidence (cross-hybridisation studies) indicate the distinctness of S. hermaphroditum n. sp. from other Steinernema spp. This new species is characterised by the presence of hermaphrodites in the first adult generation. Key morphological diagnostic characters include: a digitate tail with a mucro and a glandular spermatheca filled with sperm in the first generation hermaphrodite; the value of D%; the morphology of the male spicules and gubernaculum and the number and arrangement of the genital papillae; the values of D%, E% and the pattern of the lateral field of the third-stage infective juvenile. Additionally, molecular evidence obtained from ITS rDNA RFLP profiles, 28S rDNA sequence analyses, and phylogenetic reconstruction provide further evidence to establish this nematode as a new species.
- Campbell, J. F., Lewis, E. E., Stock, S. P., Nadler, S., & Kaya, H. K. (2003). Evolution of host search strategies in entomopathogenic nematodes. Journal of Nematology, 35(2), 142-145.More infoPMID: 19265988;PMCID: PMC2620628;Abstract: There is interspecific variation in infective juvenile behavior within the entomopathogenic nematode genus Steinernema. This variation is consistent with use of different foraging strategies along a continuum between ambush and cruise foraging. To address questions about the evolution of foraging strategy, behavioral and morphological characters were mapped onto a phylogeny of Steinernema. Three species, all in the same clade, were classified as ambushers based on standing bout duration and host-finding ability. One clade of six species were all cruisers based on both host-finding and lack of standing behavior. All species in the ambusher clade had a high rate of jumping, all species in the cruiser clade had no jumping, and most intermediate foragers exhibited some level of jumping. Response to volatile and contact host cues was variable, even within a foraging strategy. Infective juveniles in the ambusher clade were all in the smallest size category, species in the cruiser clade were in the largest size categories, and intermediate foragers tended to be more intermediate in size. We hypothesize that the ancestral Steinernema species was an intermediate forager and that ambush and cruise foraging both evolved at least once in the genus.
- Hazir, S., Keskin, N., Stock, S. P., Kaya, H. K., & Özcan, S. (2003). Diversity and distribution of entomopathogenic nematodes (Rhabditida: Steinernematidae and Heterorhabditidae) in Turkey. Biodiversity and Conservation, 12(2), 375-386.More infoAbstract: The diversity and distribution of entomopathogenic nematodes in the families Steinernematidae and Heterorhabditidae were assessed throughout an extensive soil survey in Turkey during 1999 and 2000. Entomopathogenic nematodes were recovered from six out of seven regions sampled, with 22 positive sites (2%) out of 1080 sites sampled. A single nematode isolate was recovered at each of the positive sites, of which 15 were steinernematid isolates and seven were heterorhabditid isolates representing a total of four species. Based on morphometric and molecular data, the nematode species were identified as Heterorhabditis bacteriophora, Steinernema feltiae, S. affine, and Steinernema n. sp. The most common species was S. feltiae, which was isolated from 10 sites in six regions, followed by H. bacteriophora from seven sites in five regions, S. affine from four sites in two regions, and Steinernema n. sp. from one site. Heterorhabditis bacteriophora and S. feltiae have been found in many parts of the world, whereas S. affine, so far, has only been recovered in Europe until our survey. Steinernema affine was isolated from the European (Marmara) as well as the Asiatic region (Middle Anatolia) of Turkey. A new undescribed Steinernema sp. was isolated from the most eastern region (East Anatolia) of Turkey. Soils of the positive sites were classified as sandy, sandy loam, or loam (68.2%) and sandy-clay-loam or clay loam (31.8%) and the pH ranged from 5.6 to 7.9. The habitats from which the entomopathogenic nematodes were isolated were broadly classified as disturbed (59.1%), which included agricultural fields and poplar planted for lumber and wind breaks, and undisturbed (40.9%), which included pine forest, grassland, marsh and reed sites. Steinernema feltiae, S. affine, and H. bacteriophora were recovered from both disturbed and undisturbed habitats. The new Steinernema sp. was recovered from grassland. Our survey showed that these nematodes occur widely throughout Turkey, but at a frequency below that reported for other parts of the world.
- Hazir, S., Stock, S. P., & Keskin, N. (2003). A new entomopathogenic nematode, Steinernema anatoliense n. sp. (Rhabditida: Steinernematidae), from Turkey. Systematic Parasitology, 55(3), 211-220.More infoPMID: 12878850;Abstract: A description is given of Steinernema anatoliense n. sp. (Rhabditida: Steinernematidae), an entomopathogenic nematode isolated from soil samples collected in the locality of Kars, East Anatolia, Turkey. Cross-hybridisation, morphological and molecular studies (RFLP analysis) indicated the distinctness of S. anatoliense n. sp. from other Steinernema species. Diagnostic characters include: body length of third-stage infective juvenile (507-580 μm); lateral field pattern with 6-8 longitudinal ridges; tail shape of the first generation male with a cuticular mucro; shape of the spicules and gubernaculum; and arrangement of the genital papillae. In addition, RFLP analysis of the ITS region of rDNA shows S. anatoliense n. sp. to be distinct from 50 other Steinernema species and isolates.
- Stock, S. P., & Koppenhöfer, A. M. (2003). Steinernema scarabaei n. sp. (Rhabditida: Steinernematidae), a natural pathogen of scarab beetle larvae (Coleoptera: Scarabaeidae) from New Jersey, USA. Nematology, 5(2), 191-204.More infoAbstract: Steinernema scarabaei n. sp. (Rhabditida: Steinernematidae) is a new entomopathogenic nematode isolated from larvae of the scarab beetles Anomala (= Exomala) orientalis and Popillia japonica from turfgrass in New Jersey, USA. Morphology, hybridisation and molecular studies indicated the distinctness of S. scarabaei n. sp. from other Steinernema spp. Distinctive diagnostic characters include: the presence of a mucronated tail in both first generation adults; the presence of a ventrally bifurcated mucro in the first generation female tail; the size and shape of the spicules and gubernaculum and the arrangement of the genital papillae of the male; third-stage infective juvenile with total body length of 890-959 μm and lateral field with eight longitudinal ridges. RFLP analysis of the ITS region of rDNA showed S. scarabaei n. sp. to be distinct from 50 other Steinernema species and isolates. In addition, phylogenetic interpretation of sequence data from the LSU of rDNA provided further evidence for autapomorphies and separate species status for S. scarabaei n. sp.
- Stock, S. P., Griffin, C. T., & Burnell, A. M. (2002). Morphological characterisation of three isolates of Heterorhabditis Poinar, 1976 from the 'Irish group' (Nematoda: Rhabditida: Heterorhabditidae) and additional evidence supporting their recognition as a distinct species, H. downesi n. sp.. Systematic Parasitology, 51(2), 95-106.More infoPMID: 11924599;Abstract: The morphological variation of three representative isolates of the 'Irish group' of Heterorhabditis was examined. First generation hermaphrodites were characterised by having a blunt and mucronate tail. Females (second generation) and third-stage infective juveniles were also distinguished by the morphology of the tail and the presence of a refractile projection in the tail tip. Males were characterised by the position of the excretory pore and by the value of ratio SW. These morphological features do not fit the description of currently recognised Heterorhabditis species, and provide additional evidence in support for the consideration of the Irish group as a new species. A description of this species, as H. downesi n. sp., is provided.
- Stock, S. P., Ley, P. D., Ley, I. D., Mundo-Ocampo, M., Baldwin, J. G., & Nadler, S. A. (2002). Panagrobelus stammeri Rühm, 1956 and Plectonchus hunti n. sp.: Implications of new morphological observations for characterisation of these genera (Nematoda: Panagrolaimoidea). Nematology, 4(3), 403-419.More infoAbstract: A detailed morphological description (light and scanning electron microscope observations) is given of two isolates currently used in molecular and developmental studies: PDL0024, Panagrobelus stammeri Rühm, 1956 and PDL0025, a new species herein described as Plectonchus hunti n. sp. We redescribe the lip region, interpret the orientation of the lips in P. stammeri and provide additional morphological and morphometric diagnostic features. Plectonchus hunti n. sp. is characterised by the bifurcating spicule tip and by the placement of the male genital papillae in a 3/3 + p + 2 arrangement. Additionally, females of this new species can be differentiated from other species of Plectonchus by the more anterior position of the vulva, the more anterior location of the excretory pore and the tail morphology. An emended diagnosis for this genus is provided. In this study we demonstrate that both studied taxa share morphological similarities, such as the presence of a 'cephaloboid-type' spermatheca. Our observations also indicate slight but consistent differences in cell composition of the female reproductive system between these two taxa.
- Hazir, S., Hazir, S., Stock, S., Stock, S., Kaya, H. K., Kaya, H. K., Koppenhöfer, A. M., Koppenhöfer, A. M., Keskin, N., & Keskin, N. (2001). Developmental temperature effects on five geographic isolates of the entomopathogenic nematode Steinernema feltiae (nematoda: Steinernematidae). Journal of Invertebrate Pathology, 77(4), 243-250.More infoPMID: 11437527;Abstract: The development of five geographic isolates of Steinernema feltiae at 5, 8, 10, 15, 20, 25, and 28°C in wax moth, Galleria mellonella, larvae was examined. The isolates were from Mediterranean (Sinop from Turkey, SN from France, and Monterey from California), subtropical (Rafaela from Argentina), and tropical (MG-14 from Hawaii) regions. All isolates caused 100% mortality of wax moth larvae and developed and produced progeny between 8 and 25°C. At 28°C, mortality was 100%, but no progeny was observed. The highest infective juvenile production was observed at 15°C for all isolates. In general, the tropical isolate, MG-14, had the lowest production of infective juveniles. The time of emergence of the infective juveniles from the host cadaver showed some differences among isolates, with the Sinop isolate having the earliest emergence time from cadavers at 15°C (10 days) and 20°C (8 days). At 25°C, the infective juveniles of the Sinop, SN, and Rafaela isolates emerged from the cadavers from 5 to 7 days. Time of host death by all isolates showed no differences at 8, 10, 15, 20, and 28°C. At 25°C for all isolates (except the MG-14), shorter times to host death were observed. Host death occurred at 12 days at 8°C, 9 to 11 days at 10°C, 4 to 5 days at 15°C, 3 days at 20°C, and 2 days at 25 and 28°C. For penetration efficiency, the Sinop, SN, and Rafaela isolates penetrated their hosts at 5, 8, and 10°C. Penetration of the infective juveniles was consistently high for all isolates at 15, 20, 25, and 28°C, but it was significantly lower for the MG-14 isolate at 15, 25, and 28°C. No progeny production occurred at 28°C, but nematode penetration did occur with the MG-14 isolate having significantly lower penetration than the other isolates. When nematodes were produced at 8, 15, and 23°C in wax moth larvae, all isolates had infective juveniles with longer body lengths at 8°C followed by 15 and 23°C. To further verify body length at the different temperatures, beet armyworm, Spodoptera exigua, larvae and dog-food agar medium were used, respectively, for in vivo and in vitro culture of the Sinop isolate. Infective juvenile body length showed the same trends, with the longest being at 8°C and decreasing in length from 15 to 23°C. The data suggest that quality of food for the nematode and temperature (that is, developmental time) influence the body length of the infective juvenile. © 2001 Academic Press.
- Stock, S. P., Campbell, J. F., & Nadler, S. A. (2001). Phylogeny of Steinernema travassos, 1927 (Cephalobina: Steinernematidae) inferred from ribosomal DNA sequences and morphological characters. Journal of Parasitology, 87(4), 877-889.More infoPMID: 11534654;Abstract: Entomopathogenic nematodes in Steinernema, together with their symbiont bacteria Xenorhabdus, are obligate and lethal parasites of insects that can provide effective biological control of some important lepidopteran, dipteran, and coleopteran pests of commercial crops. Phylogenetic relationships among 21 Steinernema species were estimated using 28S ribosomal DNA (rDNA) sequences and morphological characters. Sequences of the rDNA internal transcribed spacers were obtained to provide additional molecular characters to resolve relationships among Steinernema carpocapsae, Steinernema scapterisci, Steinernema siamkayai, and Steinernema monticolum. Four equally parsimonious trees resulted from combined analysis of 28S sequences and 22 morphological characters. Clades inferred from analyses of molecular sequences and combined datasets were primarily reliably supported as assessed by bootstrap resampling, whereas those inferred from morphological data alone were not. Although partially consistent with some traditional expectations and previous phylogenetic studies, the hypotheses inferred from molecular evidence, and those from combined analysis of morphological and molecular data, provide a new and comprehensive framework for evaluating character evolution of steinernematids. Interpretation of morphological character evolution on 6 trees inferred from sequence data and combined evidence suggests that many structural features of these nematodes are highly homoplastic, and that some structures previously used to hypothesize relationships represent ancestral character states.
- Stock, S. P., Heng, J., Hunt, D. J., Reid, A. P., Shen, X., & Choo, H. Y. (2001). Redescription of Steinernema longicaudum Shen & Wang (Nematoda: Steinernematidae); geographic distribution and phenotypic variation between allopatric populations. Journal of Helminthology, 75(1), 81-92.More infoPMID: 11316477;Abstract: Steinernema longicaudum Shen & Wang is redescribed based on a comparative morphological study of specimens from the type isolate from China, and two other isolates recovered from Korea and the USA. For the first and second generation female, the location of the vulva, shape of the vulval lips, and shape and length of the tail were newly observed diagnostic characters. A more detailed description of the morphology of the male spicules and gubernaculum, and the arrangement of the genital papillae is included. A description, based on scanning electron microscopy observations, of the lateral field pattern of the third-stage infective juveniles is also provided. Additionally, restriction fragment length polymorphism profiles based on the internal transcribed spacer region, and cross-breeding tests supplement the description of this species.
- Burnell, A. M., & Stock, S. P. (2000). Heterorhabditis, Steinernema and their bacterial symbionts - Lethal pathogens of insects. Nematology, 2(1), 31-42.More infoAbstract: The entomopathogenic nematodes (EPN) Heterorhabditis and Steinernema together with their symbiont bacteria Photorhabdus and Xenorhabdus, respectively, are obligate and lethal parasites of insects. EPN can provide effective biological control of some important lepidopteran, dipteran and coleopteran pests of commercial crops and they are amenable to large-scale culture in liquid fermentors. They are unique among rhabditids in having a symbiotic relationship with an enteric bacterium species. The bacterial symbiont is required to kill the insect host and to digest the host tissues, thereby providing suitable nutrient conditions for nematode growth and development. This review describes the general biology of EPN and their symbionts and gives an overview of studies to date on EPN biodiversity, biogeography and phylogeny. The impetus for research in EPN and their symbionts has come about because of their biological control potential, with much of the focus in EPN research having been on applied aspects relating to pest control. However EPN and their symbionts are increasingly being viewed as exciting subjects for basic research in the areas of ecology, biodiversity, evolution, biochemistry, symbiosis and molecular genetics. Much progress has been made over the past 20 years in our understanding of the basic biology and genetics of EPN and their symbionts. We are now entering a new phase in which the tools of molecular genetics are being increasingly used to address a range of biological questions in EPN research. The knowledge gained from this endeavour should ensure that EPN will become even more effective biopesticides and should also ensure that EPN and their symbionts gain prominence as unique and intrinsically interesting biological systems.
- Stock, S. P., Mráček, Z., & Webster, J. M. (2000). Morphological variation between allopatric populations of Steinernema kraussei (Steiner, 1923) (Rhabditida: Steinernematidae). Nematology, 2(2), 143-152.More infoAbstract: Morphometrics of four Canadian, three US and two European isolates representing distinct geographic populations of Steinernema kraussei (Steiner, 1923) were compared and analysed by multivariate analysis. A total of 540 individuals (270 males and 270 third-stage infective juveniles) representing the nine populations was measured. Fourteen morphometric variables were selected and subjected to principal component and canonical analyses. Results from both analyses indicate that there are morphological differences among the studied isolates, and that these differences are congruent with their geographic origin. The European isolates were shown to be distinctly different from the North American isolates. Within the North American isolates, the western isolates were distinguished from the eastern one (Parishville). No significant differences were observed between the two European isolates studied.
- Stock, S. (1998). Erratum: First record of Steinernema glaseri in Korea (Nematologica 43 (377-381)). Nematologica, 44(1), x.
- Stock, S. P., & Nadler, S. A. (1998). Revised list of type specimens on deposit in the University of California Davis nematode collection. Journal of Nematology, 30(3), 368-390.More infoPMID: 19274230;PMCID: PMC2620300;Abstract: The list of deposited type specimens is updated for the University of California Davis Nematode Collection, as recommended by the International Code of Zoological Nomenclature. The type collection includes 1,001 species and more than 11.000 individual specimens mounted on microscope slides. This list can be used as a reference to locate specimens but is not meant to clarify ambiguities that may exist concerning the type status of particular specimens.
- Stock, S. P., Somsook, V., & Reid, A. P. (1998). Steinernema siamkayai n. sp. (Rhabditida: Steinernematidae), an entomopathogenic nematode from Thailand. Systematic Parasitology, 41(2), 105-113.More infoAbstract: Steinernema siamkayai n. sp. (Rhabditida: Steinernematidae) is a new entomopathogenic nematode isolated in Lohmsak, Thailand. Morphology, hybridisation and molecular studies indicated the distinctness of S. siamkayai n. sp. from other Steinernema spp. Diagnostic characters include: the total body length (398-495 μm) and tail length (31-41 μm) of the third-stage infective juvenile and lateral field pattern with 6-8 longitudinal ridges; the presence of a tail mucro in both first and second generation females and males; the size and shape of the spicules and gubernaculum, and the arrangement of the genital papillae of the first and second generation males; and the shape of the vulva and tail of the first generation female and second generation female.
- Hominick, W. M., Briscoe, B. R., Pino, F. D., Heng, J., Hunt, D. J., Kozodoy, E., Mracek, Z., Nguyen, K. B., Reid, A. P., Spiridonov, S., Stock, P., Sturhan, D., Waturu, C., & Yoshida, M. (1997). Biosystematics of entomopathogenic nematodes: Current status, protocols and definitions. Journal of Helminthology, 71(4), 271-298.
- Koppenhöfer, A. M., Baur, M. E., Stock, S. P., Choo, H. Y., Chinnasri, B., & Kaya, H. K. (1997). Survival of entomopathogenic nematodes within host cadavers in dry soil. Applied Soil Ecology, 6(3), 231-240.More infoAbstract: Our objectives were to determine whether entomopathogenic nematode emergence from host cadavers is influenced by soil moisture, whether the nematodes can survive adverse desiccating conditions in the soil by remaining within the host cadaver, and whether differences in such an adaptation occur among species. In the first experiment, wax moth larvae killed by Steinernema glaseri, Steinernema carpocapsae, Steinernema riobravis, or Heterorhabditis bacteriophora were placed in soil water potentials ranging from -500 MPa (very dry) to -0.006 MPa (moist). No infective juveniles (IJs) emerged from cadavers at -500 MPa, and only few S. glaseri and S. carpocapsae emerged at -40 MPa. Large numbers of IJs emerged at ≥ -5 MPa from cadavers containing S. carpocapsae, S. glaseri, or H. bacteriophora. S. riobravis emerged only at ≥ -0.3 MPa. In the second experiment, cadavers were left in dry soil (-40 MPa) for various periods of time before being rehydrated. The number of IJs emerging per cadaver and the infectivity of the emerged IJs were determined. IJ emergence declined with the time that the cadavers were left in dry soil. Regression analysis predicted that IJ emergence from cadavers with S. glaseri, S. carpocapsae, H. bacteriophora, or S. riobravis would stop after 27, 62, 80, and 111 days, respectively, in dry soil. We hypothesize that S. carpocapsae, a sit-and-wait forager, survives longer than 5. glaseri because it is adapted to infect insects near the soil surface, whereas S. glaseri, an actively searching forager, is adapted to infect insects deeper in the soil profile. Cadavers colonized by S. carpocapsae, therefore, are more likely to be exposed to dehydrating conditions. H. bacteriophora, an actively searching forager, may survive longer within cadavers because the gummous consistency of its host cadavers retains moisture very efficiently. S. riobravis may survive for considerable lengths of time within cadavers in adaptation to the subtropical, semiarid climate of its geographic area of origin. © 1997 Elsevier Science B.V.
- Stock, S. P. (1997). Heterorhabditis hepialius Stock, Strong and Gardner, 1996. A junior synonym of H. marelatus Liu and Berry, 1996 (Rhabditida: Heterorhabditidae) with a redescription of the species. Nematologica, 43(6), 455-463.More infoAbstract: Heterorhabditis hepialius and Heterorhabditis marelatus were studied to evaluate their taxonomic position. Results from morphological and morphometric analysis and cross-breeding tests indicated these species are conspecific. Therefore, H. hepialius is considered a junior synonym of H. marelatus. A redescription of this taxon is presented.
- Stock, S. P., Choo, H. Y., & Kaya, H. K. (1997). An entomopathogenic nematode, Steinernema monticolum sp. n. (Rhabditida: Steinernematidae) from Korea with a key to other species. Nematologica, 43(1), 15-29.More infoAbstract: A nematode new to science, S. monticolum sp. n. (Rhabditida: Steinernematidae) found during a survey of entomopathogenic nematodes conducted throughout the nine provinces of Korea, is described. It can be separated from other members of the genus by the length of the tail mucro in adults of both generations, the shape and length of the male spicules and gubernaculum, and the arrangement of the genital papillae. The infective juvenile can be distinguished from other Steinernema species by the body width and the value of ratio a (total length divided by greatest width). An amendment of the specific name of several Steinernema species is presented. A key to the new and other Steinernema species is provided.
- Stock, S. P., Choo, H. Y., & Kaya, H. K. (1997). First record of steinernma glaseri steiner, 1992 (Nematoda, Steinernematidae) in Asia, with notes on intraspecific variation. Nematologica, 43(5), 377-381.
- Stock, S. P., Strong, D., & Gardner, S. L. (1997). Erratum: Identification of Heterorhabditis (Nematoda : Heterorhabditidae) from California with a new species isolated from the larvae of the ghost moth Hepialis californicus (Lepidoptera : Hepialidac) from the Bodega Bay Natural Reserve (Fundamental Nematology (1996) 19:6 (585-592)). Fundamental and Applied Nematology, 20(2), 206-.
- Stock, S. P., & Kaya, H. K. (1996). A multivariate analysis of morphometric characters of Heterorhabditis species (Nemata: Heterorhabditidae) and the role of morphometrics in the taxonomy of species of the genus. Journal of Parasitology, 82(5), 806-813.More infoPMID: 8885892;Abstract: A multivariate analysis on the morphometrics of 7 Heterorhabditis species was conducted to review the status of the traditional morphometric characterization methods for differentiating species of these nematodes. Results from this study showed consistency in the selection of morphometric characters for discriminating among males and infective juveniles of Heterorhabditis species. For the males, testis reflexion (TREF) and total length (LENGTH) were the variables that contributed most in the discrimination among the different species, and for the infective juveniles, tail length (TAILL) and total length (LENGTH) were the variables that contributed most. Therefore, we consider that these morphometric characters are useful and reliable, and that they should be used for the identification of Heterorhabditis species/isolates.
- Stock, S. P., Strong, D., & Gardner, S. L. (1996). Identification of Heterorhabditis (Nematoda: Heterorhabditidae) from California with a new species isolated from the larvae of the ghost moth Hepialis californicus (Lepidoptera: Hepialidae) from the Bodega Bay Natural Reserve. Fundamental and Applied Nematology, 19(6), 585-592.More infoAbstract: Classical taxonomy together with cross-breeding tests and random amplified polymorphic DNA (RAPD's) were used to detect morphological and genetic variation between populations of Heterorhabditis Poinar, 1975 from California. A new species, Heterorhabditis hepialius sp. n., recovered from ghost moth caterpillars (Hepialis californicus) in Bodega Bay, California, USA is herein described and illustrated. This is the eighth species in the genus Heterorhabditis and is characterized by the morphology of the spicules, gubernaculum, the female's tail, and ratios E and F of the infective juveniles. Information on its bionomics is provided.
- Camino, N. B., & Stock, S. P. (1994). Hexamermis macrostoma n.sp. (Nemata: Mermithidae) parasitizing the cricket Gryllodes laplatae (Orthoptera: Gryllidae) in Argentina. Fundamental and Applied Nematology, 17(5), 397-399.
- Gardner, S. L., Stock, S. P., & Kaya, H. K. (1994). A new species of Heterorhabditis from the Hawaiian Islands. Journal of Parasitology, 80(1), 100-106.More infoPMID: 8308642;Abstract: A new species of nematode of the genus Heterorhabditis (Nemata: Heterorhabditidae) was found during a survey of the soil entomopathogenic nematode fauna of the Hawaiian Islands. Heterorhabditis hawaiiensis sp. n. can be separated from all other species of Heterorhabditis by the length of the infective juvenile and the morphological characters of the spicules, gubernaculum, and bursa. Random amplified polymorphic DNA (RAPD) fragment analysis showed that this species also has a distinct genetic pattern in RAPD bands relative to the other 6 species or isolates of Heterorhabditis that were compared.
Presentations
- Roder, A., & Stock, S. P. (2018, July/summer). Effect of Xenorhabdus symbionts on postembryonic development and pheromone production in their Steinernema nematode hosts.. 9th International Symbiosis Society. Corvallis, OR,: International Symbiosis Society.
- Stock, S. P. (2018, August/summer). Ray Akhurst: A legacy of groundbreaking contributions in insect pathology and nematology. Society for Invertebrate Pathology- Founders Lecture Opening Ceremony. Gold Coast, Australia.
- Stock, S. P. (2018, February/spring). Research Opportunities in Nematode-Bacteria Symbiosis. UBRP - Faculty Talks. UA Campus: UBRP.
- Stock, S. P. (2018, March/spring). Why mentoring involves more than advising: A perspective from the STEM Field. Reducing Time to Doctoral Degree Seminar Series. UA Campus: Graduate College.
- Peterson, B., Yousefelahi, M., & Stock, S. P. (2017, August). Transcriptional evidence of symbiont-modulated metabolism in the entomopathogenic nematode Steinernema carpocapsae (Nematoda: Steinernematidae). San Diego, CA 8/17.. 50th Annual Meeting Society for Invertebrate Pathology. La Jolla, CA, USA: Society for Invertebrate Pathology.
- Stock, S. P. (2017, April). Role of Type VI Secretion System in Entomopathogenic Xenorhabdus Bacteria. Molecular Symposium, Pacific Branch, Entomological Society of America, Portland, OR, USA.Pacific Branc, Entomological Society of America.
- Stock, S. P. (2017, November). Harnessing an Arizona-Native Insect Pathogenic Bacterium for Natural Products with Medical Applications. CALS 496S/596S-Frontiers in Life Sciences Seminar Series. University of Arizona, Tucson, AZ: CALS.More infoThis was a 15 min seminar at the CALS Frontiers in Life Sciences Seminar Series. The seminar was an introduction of research topic and goals of recently funded iViP grant (See Research: Grants and Contracts Section for details).Graduate students in the college sign for credits and attend the seminar series.
- Stock, S. P., & McQuade, R. (2017, August). McQuade R. and Stock, S. P. Role of Type VI Secretion System in the entomopathogenic bacterium Xenorhabdus bovienii (Enterobacteriaceae).. 50th Annual Meeting Society for Invertebrate Pathology. la Jolla, CA, USA: Society for Invertebrate Pathology.
- Stock, S. P., & Roder, A. (2017, August). Xenorhabdus symbionts’ influence on Ascaroside Production and Development of First Generation Adults of their Steinernema Hosts.. 50th Annual Meeting Society for Invertebrate Pathology. La Jolla, CA, USA: Society for Invertebrate Pathology.
- Stock, S. P. (2016, July). Photorhabdus l. sonorensis secondary metabolites and their application for the control of plant pathogenic microbes and nematodes.. Society of Nematologists and Organization of Nematologists of Tropical America joint meeting. Montreal Canada: ociety of Nematologists and Organization of Nematologists of Tropical America.More infoSpeaker at the "Nematode- Microbe Interactions Symposium",
- Stock, S. P. (2016, July). Who one associates with matters: Effect of Xenorhabdus bovienii (Enterobacteriaceae) symbionts on the fitness of three Steinernema (Nematoda: Steinernematidae) hosts. International Congress on Invertebrate Pathology and Microbial Control and the 49th Annual Meeting of the Society for Invertebrate Pathology. Tours, France.: Society for invetebrate Pathology.More infoOral presentation at the Nematode Division Session.
- Stock, S. P. (2016, March). Research Opportunitieswith Nematode-Bacteria Symbiosis. Microbiology Club, Microbiology Program, Univ. ARizona. University of Arizona, Tucson, AZ: Microbiology Club.
- Stock, S. P. (2016, October). Budgeting for a Grant Proposal. Grant Writing Workshop for University Fellow., Sponsored by the UA Graduate CenterThe Graduate Center, University of Arizona.
- Stock, S. P. (2016, September). What funding agencies want: tips for getting your research funded. Grant Writing Workshop for University Fellow., Sponsored by the UA Graduate Center. University of Arizona, Tucson AZ: The Graduate Center, Univerity of Arizona.
- McMullen, J. G., & Stock, S. P. (2015, August). Phenotypic diversity in the virulence of the entomopathogenic bacterium Xenorhabdus bovienii (Gamma-Proteobacteria: Enterobacteriaceae) reveals a type VI secretion system in its pan-genome. International Congress on Invertebrate Pathology and Microbial Control and the 48th Annual Meeting of the Society for Invertebrate Pathology. Vancouver, Canada: Society for Invertebrate Pathology.
- Orozco, R. A., & Stock, S. P. (2015, August). In search for novel bioactive molecules: Genome mining of the entomopathogenic bacterium Photorhabdus luminescens sonorensis (Gamma-Proteobacteria: Enterobacteriaceae). International Congress on Invertebrate Pathology and Microbial Control and the 48th Annual Meeting of the Society for Invertebrate Pathology. Vancouver, Canada: Society for Invertebrate Pathology.
- Stock, S. P. (2015, April). Entomopathogenic nematodes and their bacterial symbionts: A new model system for studying the chain of infection. Microbiology Seminar. Tucson, AZ: Microbiology Program Seminar, School of Animal and Comparative Biomedical Sciences, University of Arizona.
- Stock, S. P. (2015, July). The epic friendship of Steinernema nematodes and their bacterial symbionts. 2015 International Symbiosis Society Meeting. Lisbon, Portugal: International Symbiosis Society Meeting.
- Stock, S. P. (2015, May). Entomopathogenic and Parasitic Nematodes for Biological Control of Insect Pests. Departmental Seminar. Universidad Nacional de Chile, Department of Plant Protection: Universidad Nacional de Chile, Department of Plant Protection.
- Stock, S. P. (2015, May). Nematode-Bacterium-Insect Tripartite Symbiosis. EIS-GIDP Retreat. Santa Rita Experimental Station, University of ARizona: EIS-GIDP.More infoPresented ongoing research program in my laboratory
- Stock, S. P. (2015, May). Pathogens and parasites of horse flies and their application in biological control tactics. Fondo de Innovación para la Competitividad (FIC) Meeting, Puerto Montt, Chile. Puerto Montt, Chile: Fondo de Innovación para la Competitividad (FIC).
- castagnola, A., & Stock, S. P. (2015, August). Insecticidal action, cellular interactions and response of combinations of Photorhabdus-Insect-Related (Pir) and Bacillus thuringiensis Crystal (Cry) Toxins. International Congress on Invertebrate Pathology and Microbial Control and the 48th Annual Meeting of the Society for Invertebrate Pathology. Vancouver, Canada: Society for Invertebrate Pathology.
- Castagnola, A., Davis, N., Molina, B., & Stock, S. P. (2014, August 3-7). Differential PirAB expression of the entomopathogenic bacterium Photorhabdus luminescens (Enterobacteriaceae) based on tissue association and portal of entry to the insect host. 2014 International Congress on Invertebrate Pathology and Microbial Control and 47th Annual Meeting of the Society for Invertebrate Pathology. Mainz, Germany: Society for Invertebrate pathology.
- Castagnola, A., Molina, B., Davis, N., McMullen, J., & Stock, S. P. (2014, April). Insect tissue specificity of the bacterium Photorhabdus luminescens and its nematode host during the infection process. Annual Meeting, Pacific Branch, Entomological Society of America. tucson, Az, USA: PB, ESA.
- McMullen, J., Bisch, G., Pages, S., Ogier, J., Gaudriault, S., & Stock, S. P. (2014, August 3-7). Candidate Virulence Loci in the Pan-Genome of the Entomopathogenic Bacterium Xenorhabdus bovienii (γ-Proteobacteria: Enterobacteriaceae). 2014 International Congress on Invertebrate Pathology and Microbial Control and 47th Annual Meeting of the Society for Invertebrate Pathology. Mainz, Germany: Society for Invertebrate Pathology.
- McMullen, J., Gaudriault, S., & Stock, S. P. (2014, January). Comparative Genomic Analysis of the Steinernema—Xenorhabdus Bovienii Symbiosis: Revealing Novel Regions in Mutualism and Pathogenicity. 25th Undergraduate Biology Research Program Annual Conference. Tucson, Arizona, USA: Undergraduate Biology Research Program.
- Stock, S. P. (2014, April). My career path in retrospect…. CALS Ambassadors Career Meeting. UA Campus, Tucson, AZ, USA: CALS Ambassadors.
- Stock, S. P. (2014, March). Importance of Bioethics in Research. Bioethics Workshop. UA Campus, Tucson, AZ, USA: PERT.More infoParticipated in a panel discussion session
- Stock, S. P., Falk, D., & Rasmusse, C. (2014, December). Diversity and abundance of nematode communities as indicators of post-fire resilience and soil properties in Arizona’s Sky Islands. CALS- RIC Progress Meeting. UA Campus, Tucson, AZ: CALS RIC Program.
- Stock, S. P. (2012, August). Contributions of cognate and non-cognate symbionts to nematode host fitness. Society for Invertebrate Pathology 46th Annual Meeting. Buenos Aires, Argentina: Society for Invertebrate Pathology.More infoBroadcast
- Stock, S. P. (2012, August). Insect host diet and its impact on the fitness of entomopathogenic nematodes and their symbiotic bacteria. Society for Invertebrate Pathology 46th Annual Meeting. Buenos Aires, Argentina: Society for Invertebrate Pathology.More infoBroadcast
- Stock, S. P. (2012, March). The Evolutionary History Entomopathogenic Nematodes and their Bacterial Symbionts: Promiscuity or Fidelity?. Evolution of C.elegans and other Nematode Meeting. Cold Spring Harbor, NY.More infoBroadcast
- Stock, S. P. (2012, September). Nematodes and bacteria symbiosis. Chemistry and Biochemistry and Microbiology Departments Annual Retreat. Tucson, Arizona.More infoBroadcast
Poster Presentations
- Allen, J., Peterson, B., & Stock, S. P. (2018, January/Spring). Examining stress conditions and their effect the maintenance of the bacterial symbionts Steinernema carpocapsae nematodes. UBRP Annual Conference. Tucson, AZ, USA: UBRP.
- Bradshaw, C., McQuade, R., & Stock, S. P. (2018, January/Spring). Novel T6SS in the bacterium Xenorhabdus bovienii may impact insect virulence and bacterial competition. UBRP Annual Conference. Tucson, AZ: UBRP.
- Duong, A., & Stock, S. P. (2018, summer). Bioactivity-guided fractionation to identify novel secondary metabolites produced by the insect pathogenic bacterium Photorhabdus l. sonorensis as potential antibacterial and antifungal agents. IRACDA Conference. Atlanta GA, USA.
- Noumeh, D., Peterson, B., & Stock, S. P. (2018, April/spring). Exploring symbiont-mediated thermal tolerance in entomopathogenic nematodes using experimental evolution. Annual Meeting American Society Of Microbiology Southern-Nevada Branch. Las Vegas, Nevada: American Society Of Microbiology Southern-Nevada Branch.
- Roder, A., & Stock, S. P. (2018, July/Summer). Xenorhabdus symbionts impact ascroside production and reproduction of first generation Steinernema entomopathogenic nematodes.. Entomological Society of America Annual Meeting. Vancouver, Canada.: Entomological Society of America.
- Yousefelahi, M., Peterson, B., & Stock, S. P. (2018, January/Spring). Developing methods to extract and measure RNA in Steinernema carpocapsae infective juvenile nematodes (Nematoda: Steinernematidae). UBRP Annual Conference. Tucson, AZ, USA: UBRP.
- Bradshaw, C., McQuade, R., & Stock, S. P. (2017, April). A novel type six secretion system in the insect-pathogenic bacterium Xenorhabdus bovienii. 56th ASM Arizona/S. Nevada Annual Meeting,. Tucson, AZ, USA: ASM Arizona/S. Nevada Branch.
- Roder, A., Butcher, R., & Stock, S. P. (2017, April). Culture conditions impact ascarosides production in entomopathogenic Steinernema nematodes (Nematoda: Steinernematidae).. 56th ASM Arizona/S. Nevada Annual Meeting. Tucson, AZ, USA: SM Arizona/S. Nevada Branch.
- Shelp, M., Elmore, A., McQuade, R., & Stock, S. P. (2017, April). Generating a fluorescently-labeled Photorhabdus luminescens to study colonization of the nematode intestine. 56th ASM Arizona/S. Nevada Annual Meeting. Tucson, AZ, USA: ASM Arizona/S. Nevad.
- Stock, S. P., Barrios, T., & Roder, A. (2017, May). Xenorhabdus Symbionts Influence the development of first generation adults of their Steinernema nematode hosts. Ecology and Evolutionary Biology Annual Poster Session, University of Arizona. Tucson, AZ, USA: EEB Department, University of Arizona.
- Stock, S. P., Bradshaw, C., & McQuade, R. (2017, April). Identifying type six secretion system effectors in the insect-pathogenic bacterium Xenorhabdus bovienii.. 56th ASM Arizona/S. Nevada Branch Annual Meeting. Tucson, AZ, USA: ASM Arizona/S. Nevada Branch.
- Stock, S. P., Bradshaw, C., & McQuade, R. (2017, August). A novel Type Six Secretion System in the entomopathogenic bacterium Xenorhabdus bovienii (Gamma-Proteobacteria: Enterobacteriaceae) may impact insect virulence and bacterial competition.. 50th Annual Meeting Society for Invertebrate Pathology. la Jolla CA, USA: Society for Invertebrate Pathol.
- Stock, S. P., Forlastro, I., McQuade, R., & Vishwanathan, V. (2017, August). Evaluation of Galleria mellonella (Lepidoptera: Pyralidae) as a complementary model organism to study enteropathogenic E. coli.. 50th Annual Meeting Society for Invertebrate Pathology. La Jollao, CA, USA: Society for Invertebrate Patholology.
- Stock, S. P., Noumeh, D., & Peterson, B. (2017, November). Investigation of symbiont-mediated thermal tolerance in entomopathogenic nematodes.. Annual Biomedical Research Conference for Minority Student Annual Meeting. Phoenix, AZ, USA: l Biomedical Research for Minority Students.
- Stock, S. P., Peterson, B., & McMullen, J. (2017, April). Rearing conditions and symbiont presence modulate Steinernema carpocapsae infective juvenile metabolism.. 56th ASM Arizona/S. Nevada Branch Annual Meeting. Tucson, AZ,, USA: ASM, AZ/Nevada Branch.
- Molina, B., & Stock, S. P. (2016, January). Symbiont segregation in infective juvenile populations of Steinernema carpocapsae nematodes (Nematoda: Steinernematidae). 27th Undergraduate Biology Research Program (UBRP) Annual Conference. Tucson, AZ: Undergrdauate Biology Research Program.
- Roder, A., & Stock, S. P. (2016, September). Preferred portal of entry of entomopathogenic nematodes (Steinernematidae, Heterorhabditidae) during the infection process. International Conference of Entomology (ICE). Orlando, Florida: Various Entomloogical Societies.
- Roder, A., Wang, Y., Butcher, R., Kaplan, F., & Stock, S. P. (2016, September). Role of Xenorhabdus Bacteria on Pheromone Production by Steinernema Nematodes: Impact on Nematode Fitness and Formulation. Annual PIs Meeting, USDA NIFA, A-1111 Program. Orlando, Florida.
- McMullen, J. G., & Stock, S. P. (2015, July). Role of T6SS locus in Xenorhabdus bovienii (γ-Proteobacteria), the bacterial symbionts of Steinernema nematodes (Steinernematidae). 2015 International Symbiosis Society Meeting. Lisbon, Portugal: International Symbiosis Society Meeting.
- Orozco, R. A., & Stock, S. P. (2015, July). Crude extracts of the entomopathogenic bacterium, Photorhabdus l. sonorensis (Enterobacteriaceae) and their effect on two plant-parasitic nematodes: Meloidogyne incognita and Anguina pacificae (Nematoda: Tylenchina). 2015 International Symbiosis Society Meeting. Lisbon, Portugal: International Symbiosis Society Meeting.
- McMullen, J., Ogier, J., Bisch, G., Pages, S., Gaudriault, S., & Stock, S. P. (2014, April). Insect pathogenic factors of Xenorhabdus bovienii (Enterobacteriaceae) revealed by a comparative genomic analysis and virulence assays. Anual Meeting Pacific Branch Entomological Society of America. Tucson, AZ, USA: Pacific Branch, ESA.
- Molina, B., Castagnola, A., Davis, N., & Stock, S. P. (2014, April). Insect related toxins of Photorhabdus bacteria (Enterobacteriaceae) in relation with lipid biosynthesis and developmental regulation gene expression of its nematode host over a 3-day infection period. Annual Meeting Pacific Branch, Entomological Society of America. Tucson, AZ, USA: PB, ESA.
- Orozco, R., & Stock, S. P. (2014, April). Entomopathogenic Photorhabdus bacteria (Enterorbacteriaceae): A novel source of compounds for control of plant-parasitic nematodes. Annual Meeting Pacific Branch, Entomological Society of America. Tucson, AZ, USA: PB, ESA.
- Stock, S. P. (2014, October). Insect Pathogens and Parasites: Novel Model Systems for Biological and Biomedical Research. CALS Research Conference. UA Campus, Tucson, AZ, USA: CALS.
- Stock, S. P. (2012, May). Diversity and Seasonal Fluctuation of Nematodes Populations in Oak Woodlands from Southern Arizona s Sky Islands. International Conference on Climate AdaptationInternational Conference on Climate Adaptation.
- Stock, S. P. (2012, October). Interactions between the fungus Fusarium oxysporum and the entomopathogenic nematode Heterorhabditis sonorensis. XXI Congreso Chileno de Fitopatologia [XXI Chilean Congress on Plant Pathology]. Puerto Varas, Chile: XXI Congreso Chileno de Fitopatologia [XXI Chilean Congress on Plant Pathology].
- Stock, S. P. (2012, September). A novel EPN strain from Turkey with misleading signs of infection. Europena Society of Nematologists. Adana, Turkey: Europena Society of Nematologists.
Others
- Stock, S. P. (2013, March). Insect Pathogens: Their application in Pest management. Universidad de Costa Rica.More infoManual. included theory and laboratory activities for the teaching of an Insect pathology Course at Universidad de Costa Rica. This work was written in Spanish.