- Determine how specificity is achieved in environmentally transmitted bacteria-host associations.
- Identify aspects of bacterial behavior that are essential to tissue tropism.
- Characterize the molecular mechanisms that underlie successful tissue colonization.
- Comparatively examine virulence factors of pathogenic bacteria that are required for symbiotic colonization.
- Define the spatial patterns and temporal dynamics of non-clonal bacterial populations within monospecific associations.
- Determine the suite of changes in bacterial gene expression that are induced by the environment of host tissues.
In recent years we, in conjunction with other labs working with Vibrio fischeri and the squid host, have developed and applied novel technical approaches to facilitate our research aims. Specifically, we have developed molecular genetics in this bacterium, sequenced the genome of a light organ isolate, and created transposon mutant libraries and glass-chip and Affymetrix DNA microarrays. In addition, using fluorescently labeled V. fischeri cells and confocal microscopy, we are characterizing the behavior of these bacteria during the initiation and development of symbiosis in living squid. Finally, by adapting microinjection techniques, we have begun to introduce symbiotically incompetent bacteria into the light organ to determine the colonization stage in which they are defective.
Current Research Directions
- Mutagenesis Library: Construction of an ordered mutant library of the bacterial symbiont, Vibrio fischeri.
- Flagella in Accommodation and Persistence: Investigating the role of flagella in the later stages of colonization of the light organ using microinjection techniques.
- Competitive Dominance: The earliest site of species specificity in the V. fischeri-E. scolopes partnership is the dominance of V. fischeri in the host-derived mucus.
- Natural Competence: Investigating the relationship between chitin and extracellular DNA uptake and use in V. fischeri.
- AinS-mediated Quorum Sensing: Determining the role of the Vibrio fischeri AinS quorum-sensing system in the colonization of Euprymna scolopes.
- Bacterial Diversity: Can static and dynamic patterns of diversity existing in natural V. fischeri populations found in E. scolopes light organs be related to current ecological and evolutionary theory?
- Nitric Oxide Stress in the light organ environment: Study on the mechanisms of how Vibrio fischeri responds to and survives NO stress during symbiotic colonization to Euprymna scolopes.