E-Board No. 93

November 1, 2010

Dear Colleagues;

Please forward the following message to your talented undergraduate and Masters students.

C Smith

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Funded Positions for PhD Students in Comparative Immunology

Laboratories of
Dr Ioannis Eleftherianos
and
Dr. L. Courtney Smith
DEPARTMENT OF BIOLOGICAL SCIENCES, George Washington University, Washington DC, USA

The Eleftherianos Lab
Integrative molecular biology of insect infection and immunity: interactions between entomopathogenic nematodes and their symbiotic bacteria with the insect immune system.

Background information: The bacterium Photorhabdus luminescens lives in a ‘symbiosis of pathogens’ with the nematode Heterorhabditis bacteriophora, which invades and kills insects. Unlike other animals associated with bacterial symbionts, Heterorhabditis nematodes are viable in the absence of Photorhabdus. Consequently, each partner of this symbiotic/pathogenic relationship can be separated and studied in isolation and in combination, thus enabling pathogenesis and symbiosis to be studied separately or together. Recent work has also begun to use the powerful genetics of the model insect host Drosophila melanogaster to dissect the complex molecular interactions involved. The great advantage of this unique system is that all three players (Drosophila, Photorhabdus and Heterorhabditis) in the interaction can be genetically manipulated and the availability of the genome sequences for the three organisms facilitates functional genomics comparisons, reverse genetic screens and systems biology-based approaches.

Rationale and objectives: The concept behind this work is that successful pathogens of insects like Heterorhabditis and Photorhabdus are likely to possess adaptations that allow them to overcome the insect immune system. Knowledge of these will allow us to develop new reagents with which to investigate insect immune function. Insect immunity has in recent years proved fertile ground for the discovery of novel genes also important in the innate immune responses of higher animals. Moreover, microbial genes that encode insect-specific immunotoxins may also prove to be useful in insect control.

The goal of our research is to use the tripartite system consisting of three model organisms in order to investigate the molecular and evolutionary basis of insect immunity, bacterial symbiosis/pathogenicity and nematode parasitism, and to understand the basic principles of the complex interactions between these important biological processes. This system promises to reveal not only how pathogens evolve virulence but also how two pathogens can come together to exploit a common host.

References:
Waterfield, N.R., Ciche, T. and Clarke, D. (2009). Photorhabdus and a host of hosts. Annual Reviews Microbiolology 63, 557-574.

Eleftherianos, I., Joyce, S., ffrench-Constant, R.H., Clarke, D.J. and Reynolds, S.E. (2010). Probing the tri-trophic interaction between insects, nematodes and Photorhabdus. Parasitology 26, 1-12.

Eleftherianos, I., Boundy, S., Joyce, S.A., Aslam, S., Marshall, J.W., Cox, R.J., Simpson, T.J., Clarke, D.J., ffrench-Constant, R.H. and Reynolds, S.E. (2007). An antibiotic produced by an insect-pathogenic bacterium suppresses host defenses through phenoloxidase inhibition. Proceedings of the National Academy of Sciences U.S.A. 104, 2419-2424.

ffrench-Constant, R.H., Eleftherianos, I and Reynolds, S.E. (2007). Nematode symbionts shed light on invertebrate immunity. Trends in Parasitology 23, 514-517.

Lemaitre, B. and Hoffmann, J. (2007). The host defense of Drosophila melanogaster. Annual Review of Immunology 25, 697-743.


The Smith Lab
Invertebrate Immunology: Innate immune responses to pathogens and immune diversification in the purple sea urchin.

Background: Marine invertebrates are challenged with large numbers of bacteria and viruses in sea water and the marine substrate. Recent analysis of the genome of the purple sea urchin, Strongylocentrotus purpuratus, has shown that it has a highly sophisticated innate immune system. We are evaluating one the of immune gene families in this species; the Sp185/333 genes that encode a diverse set of proteins. Animals have ~260 Sp185/333 isoforms that are present as different suites of proteins in individual animals. The proteins are expressed by two of the six different types of immune cells, or coelomocytes in response to immune challenge. We estimate ~50 genes in the genome that are small, have two exons, have multiple repeats, have blocks of sequence called elements, and are surrounded by microsatellites. Sequence diversification in the proteins is likely the result of a combination of gene duplication/deletion, segmental duplication, gene conversion, RNA editing, post translational modifications, etc.

Rationale and objectives: Because echinoderms are phylogenetically related to chordates (that includes mammals), investigations of the sea urchin immune system may provide insights into the evolutionary history of the immune system in higher deuterostomes. Goals of our research are to understand the diverse Sp185/333 system, including the breath of protein function, the source(s) of gene sequence diversity, activities of promoters that regulate expression for the different Sp185/333 genes, and the mechanism of RNA editing

References: (all are available from http://www.gwu.edu/~biology/faculty/smith.cfm)
Ghosh JG, KM, Buckley, SV Nair, DA Raftos, C Miller, AJ Majeske, T Hibino, JP Rast, M Roth, LC Smith. 2010. Sp185/333: A novel family of genes and proteins involved in the purple sea urchin immune response. Developmental and Comparative Immunology, 34:235-245 (review)

Miller, CA, KM Buckley, RL Easley & LC Smith. 2010. An Sp185/333 gene cluster from the purple sea urchin and putative microsatellite-mediated gene diversification. BMC Genomics, 11:575.

Buckley, KM, S Munshaw, TB Kepler & LC Smith. 2008. The 185/333 gene family is a rapidly diversifying host-defense gene cluster in the purple sea urchin, Strongylocentrotus purpuratus. Journal of Molecular Biology, 379:912-928.

Buckley, KM, DP Terwilliger, LC Smith. 2008. Sequence variations in 185/333 messages from the purple sea urchin suggest post-transcriptional modifications to increase immune diversity. Journal of Immunology, 181:8585-8594.

Brockton V., JH Henson, DA Raftos, AJ Majeske, Y-O. Kim & LC Smith. 2008. Localization and diversity of 185/333 proteins from the purple sea urchin, Strongylocentrotus purpuratus (Stimpson); unexpected protein size range and expression in a new coelomocyte type. Journal of Cell Science, 121:339-348.

Buckley, KM & LC Smith. 2007. Extraordinary diversity among members of the large gene family, 185/333, from the purple sea urchin, Strongylocentrotus purpuratus. BMC Molecular Biology, 8:68.


Research environment at GWU: Our labs work closely with each other and with other groups in the Department and the University that have interests in evolution, parasitology, development and invertebrate biology. The Department of Biological Sciences is excellently equipped for work with invertebrates and microbes and GW has state-of-the-art facilities for molecular biology including high throughput sequencing, a genomics core, a microscopy suite, and a flow cytometry facility. Major scientific organizations (National Science Foundation, National Institutes of Health, Howard Hughes Medical Institute including Janelia Farm) in addition to other Academic Institutions (Georgetown Univ, Univ of Maryland, American Univ, Howard Univ, George Mason Univ, etc) are located in the vicinity of the GW Foggy Bottom campus. Quality of life in Washington D.C. is very high with easy access to the Smithsonian Institution, the National Zoo and USDA laboratories.

Profile of candidates: The positions are suitable for highly motivated students with MS or BS degrees who are interested in integrative biology, preferably with some experience in one or more of the following areas: molecular biology, genetics, immunology, invertebrate biology, molecular microbiology. The research requires a multidisciplinary approach with the use of molecular, cellular and immunological techniques. Students have daily opportunities to interact with other members (faculty, postdocs, grad students and undergraduates) of both labs. Good knowledge (speaking and writing) of scientific English is required.

How to apply: Interested candidates are invited to submit their application, including a cover letter, a full Curriculum Vitae, a brief description of your prior research experience, together with the names and addresses of one or more referee(s).
Application materials can be obtained on-line from (http://www.gwu.edu/apply/graduateprofessional)

For supplementary information please contact:
Dr Ioannis Eleftherianos
Email: ioannise@gwu.edu
Website: http://www.gwu.edu/~biology/faculty/eleftherianos.cfm
Phone: (202) 994-0876
or
Dr. L. Courtney Smith
Email: csmith@gwu.edu
Website: http://www.gwu.edu/~biology/faculty/smith.cfm
Phone: (202) 994-9211

Department of Biological Sciences
The George Washington University
340 Lisner Hall
2023 G St., NW
Washington, D.C., 20052
Fax: (202) 994-6100


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Message from the ISDCI President
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Professor Tony Ellis

It is with very great sorrow that I have to inform you of the death of Tony Ellis, fish immunologist and former co-Editor of Fish and Shellfish Immunology, on Sunday 24th October 20I0. Tony died peacefully, aged 63, after a period of illness. His funeral will be held on Wednesday, November 3rd.

Tony had worked at the UK Fisheries Research Service Marine Laboratory in Aberdeen, Scotland for most of his career, latterly as head of the immunology/ vaccines group. He retired in 2007. He was also an Honorary Professor within the University of Aberdeen's School of Biological Sciences.

Many ISDCI members will have known him and agree that he was a charismatic, popular and highly productive scientist. He contributed a very great deal to comparative immunology and will be sadly missed and mourned within our community. Sympathies are extended to his family, friends, colleagues and former students. In recognition of his major contribution to science, the new Marine Scotland Science building in Torry, Aberdeen, which will open soon, will be named after him. Individual, personal donations in his memory may be made to Cancer Research UK (https://donate.cancerresearchuk.org/donate.asp?id=999)

Kind regards

Val Smith
President

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