Matt Turnbull
S-225 Ag. Science N    859.257.1134 (V) 
Department of Entomology   859.323.1120 (F) 
University of Kentucky 40546-0091 

 e-mail: mwturn2@uky.edu 
Education
  • Ph.D. Candidate, Department of Entomology, UKy, Lexington, Ky.
  • M.A. Biology, College of William and Mary, Williamsburg, Va.
  • B.S. Biology, College of William and Mary, Williamsburg, Va.


Areas of Expertise 
Cell and Molecular Biology, Genetics, Immunology, Physiology, Virology 

Research
My research involves the characterization of the vinnexin and cys-motif genes of the Campoletis sonorensis Ichnovirus, a polydnavirus obligate mutualist of the endoparasitoid wasp, Campoletis sonorensis.  Female wasps, when parasitizing a lepidopteran larva, inject a dose of CsIV DNA into the host, along with an egg and accessory factors.  Viral proteins translated in the caterpillar are required for suppression of the caterpillar immune system; in essence, the virus acts like a caterpillar AIDS, an activity which is required for successful parasitization. 

The vinnexin gene family encodes proteins homologous to innexins, lepidopteran genes involved in gap junction intercellular communication.  We believe that the vinnexins interfere with normal host gap junction communication between blood cells, disrupting cellular immunity.  To date, I have shown expression of two of the four CsIV vinnexins to be limited to parasitized lepidopteran, with no concordant expression in male or female C. sonorensis; a third is transcribed in both the caterpillar and the wasp.  I am currently in the process of further characterizing vinnexin transcriptional patterns, at both temporal and tissue specific scales.  I also have recently returned from the UK, where I visited a fly gap junction lab and preliminarily showed that both vinnexins and lepidopteran innexins can form functional gap junctions. 

My second major focus is the further characterization of the cys-motif gene family of CsIV.  To date, four cys-motif genes have been studied and linked to disruption of cellular immunity.  I recently identified coding sequences for an additional six putative genes, and am collaborating with another graduate student (Torrence Gill) to characterize the spatial, temporal, and relative transcription levels of the gene family.  We believe that by comparing relative transcription patterns of the entire gene family, we may be able to elucidate the effects of genome structure on transcription levels in this unusual virus. 

Future Research
My current research on the vinnexins is focused on determining their functions.  Now that we know that the proteins form functional gap junctions, we are attempting to determine their probable role in vivo.  To this end I am performing in vitro encapsulation and dye-transfer assays, in combination with RNAi, to ascertain the roles of gap junctions in caterpillar cellular immunity, a phenomenon which has not been shown to date.  The majority of the molecular characterization is being performed in collaboration with Dr. Nathalie Volkoff (INRA-CNRS), as she has been instrumental in isolating two novel lepidopteran innexins.  In addition to the molecular and functional characterization of the vinnexins and innexins, antisera are being designed for use in immunofluorescence assays of both native and viral innexins. 

I also am involved in a developing project which focuses on the actin cytoskeleton of the primary insect immunocytes, the blood cells.  Actin is a major cellular protein, and is involved in much of a cell’s motility and responsiveness.  Previous studies have suggested qualitatively that this protein is a major target of CsIV in effecting cellular dysfunction.  Therefore, we are using a series of assays that I have developed to quantitatively determine the specific cellular and actin pathologies induced by wasp accessory factors and viral proteins.  We also will be able to use this assay to better define the role of the unusual glycosylation of the cys-motif proteins in their functions.  These studies utilize our on-site confocal microscope and allow me to experiment with image analysis, a fascinating field for me. 

Service and Professional Experience
Student Representative to UKy Entomology Faculty Assembly: 2001-present 

UKy Student Government Representative: 2001-present 
Student Representative to UKy Entomology Research Program Committee: 2001-present 

Visiting Post-graduate Researcher – Laboratory of Dr. Pauline Phelan. University of Kent at Canterbury, Department of Biosciences. November-December 2001. 

Grant Review – Cooperative Grants Program, Civilian Research and Development Foundation:  2001 

Teaching Assistant – Molecular Genetics. UKy: 2001, 2002 

Curriculum Committee for UKy Entomology: 1999-2001 

Research Technician – Isolation of Invertebrate Orthologues of Multiple Isoforms of Vertebrate B-cell Specific Activating Protein (BSAP). W&M: 1998-1999 

Teaching Assistant – Nonmajor Biology, Botany, and Biological Statistics Laboratories. W&M: 1996-1998 

Memberships

  • Sigma Xi                                                             2001-present
  • American Society for Virology                            2000-present
  • Society for Molecular Biology and Evolution     2000-present
  • Ohio Valley Entomological Association              2000-present
  • American Association for the Advancement of Science      1998-present
  • Entomological Society of America                       1997-present


Honors and Awards 

  • Dissertation Year Fellowship – UKy      2002
  • Dissertation Enhancement Award – UKy       2001
  • Student Support Award – UKy        2001
  • Student Travel Grant –  American Society for Virology     2001
  • Tuition Scholarship – UKy        2001-2002
  • First Place, President’s Prize Competition – ESA, Annual Meeting   2000
  • First Place, PhD-level Competition –  OVEA, Annual Meeting    2000
  • Commonwealth Research Award – UKy       2000
  • Daniel R. Reedy Quality Achievement Award Fellowship – UKy    1999-present
  • University Graduate Student Development Award – UKy     1999-2000
  • Department of Entomology Research Assistantship – UKy     1999-present
  • Kentucky Pest Control Scholarship – UKy       1999-2001
  • Minor Research Grant – W&M       1998-1999
  • Department of Biology Teaching Assistantship – W&M    1996-1998


Publications, Presentations and Posters

  • S. Dupas, M.W. Turnbull and B.A. Webb. Diversifying selection in a parasitoid's symbiotic virus among genes involved in inhibiting host immunity. J Mol Evol (submitted)
  • M.W. Turnbull and B.A. Webb. Perspectives on polydnavirus origins and evolution. Adv Viral Res (in press)
  • M.W. Turnbull and N.J. Fashing. Efficacy of the ventral abdominal secretion of the cockroach Eurycotis floridana as a defense allomone. J Insect Beh (in press)
  • M.W. Turnbull. Polydnaviruses and Cellular Immunosuppression in Insects. Invited Presentation (2001). University of Kent at Canterbury.
  • M.W. Turnbull & B.A. Webb. Expression of Campoletis sonorensis Ichnovirus Homologues of Invertebrate Gap Junction Proteins.  Presentation (2001). Annual Meeting of American Society for Virology.
  • S. DeBorde, K. Lindstrom, R. Hilgarth, W. Rattanadechakul, K. Shelby, L. Huang, R. Livingston, M.W. Turnbull, N. Volkoff & B.A. Webb. Structure-Gene Family Relationships in the CsIV Genome. Poster (2001). Annual Meeting of American Society for Virology.
  • M.W. Turnbull & B.A. Webb. Expression of an Invertebrate Gap Junction Homologue from the Campoletis sonorensis Ichnovirus. Presentation (2000). Joint Annual Meeting of The Entomological Society of America/Entomological Society of Canada/Société d’Entomologie du Québec.
  • M.W. Turnbull. Invertebrate Gap Junction Homologues From Campoletis sonorensis Ichnovirus. Presentation (2000). Annual Meeting of Ohio Valley Entomological Association.
  • M.W. Turnbull & B.A. Webb. Analysis of the cys-motif protein family of the Campoletis sonorensis Ichnovirus.  Presentation (2000). Annual Meeting of American Society for Virology.


Laboratory
Dr. Bruce Webb