|
Horizontal Gene Exchange and Genome Evolution of Viruses in an
Aquatic Environment (2008 – Present)
Investigator:
Marcia Marston,
Roger
Williams
University
Abstract:
Bacteriophages are responsible for the virulence of many bacterial
pathogens. Phage-encoded virulence factors include the shiga toxins in
pathogenic strains of Escherichia coli, the cholera toxin in Vibrio
cholerae, and the botulinum neurotoxins in Clostridium botulinum.
Bacteriophages can drive the emergence and evolution of new pathogenic
bacterial strains by the horizontal transfer of virulence factors and
thus an understanding of phage genome evolution has important public
health implications. This research project will examine the genetic
structure, dynamics, and evolution of phage genomes. We will test the
hypothesis that much of the current phage diversity can be attributed to
recent horizontal genetic exchange events among phages and their hosts.
A natural community of aquatic bacteriophages belonging to the
Myoviridae and Podoviridae families will be used as a model system to
address questions about phage genome evolution and the frequency of
horizontal gene transfer. PCR primers for core-viral genes as well as
host-derived genes will be designed. Viral and host-derived genes will
be sequenced from bacteriophages isolated over the past ten years as
well as from new isolates obtained from Narragansett Bay. Bioinformatic
tools will be used to analyze these sequences to: (1) construct
phylogenetic gene and genome trees, (2) compare relative rates of
divergence among genes, (3) detect and date horizontal gene transfer
events, and (4) assess the number of possible genetic exchanges among
phages and between phages and their hosts. Undergraduate students will
participate in all aspects of the research. This pilot project will
train undergraduate students both during the summer and the academic
year in key molecular genetic techniques used in biomedical research.
Students will gain experience in scientific communication, laboratory
techniques, use of key instrumentation, and bioinformatics as they
complete individual projects.
Presentations
2008 - 2009
*Amrich, C.G., Bliss, J.E., *Marston, M.F.
2008. Assessment of cyanophage diversity in coastal waters using pulsed
field gel electrophoresis and multiple molecular markers. 2008 Ocean
Sciences Meeting, Orlando, FL, March 2-7.
2007 - 2008
Amrich, C.G., Bliss, J.E.,
*Marston, M.F. 2008. Assessment of cyanophage diversity in coastal waters
using pulsed field gel electrophoresis and multiple molecular markers.
2008 Ocean Sciences Meeting, Orlando, FL, March 2-7. |