|
|
|||||||||||||
Research Description I am interested in how Vibrio fischeri can generate genetic diversity within the squid light organ, specifically by genetic exchange amongst cells within the light organ population. V. fischeri is capable of exchanging plasmids via conjugation, but could there be other mechanisms for exchange? The recent discovery of chitin-induced competence (DNA uptake) in Vibrio cholerae sparked another potential avenue for exchange: natural transformation. Transformation is the combined uptake of DNA from the environment by a bacterial cell and incorporation of this genetic information into the genome. I am currently investigating the ability of V. fischeri cells to take up extracellular DNA in vitro when cultured in the presence of chitin breakdown products. Chitin is composed of N-acteylglucosamine (NAG) monomers, and is the most abundant biopolymer in the ocean. Utilization of chitin as a nutrient source is characteristic of marine vibrios. Chitin-induced competence could certainly have practical implications for V. fischeri mutagenesis. However, it may also play a role within the squid light organ population, where chitin is present and V. fischeri cells persist in high concentrations. Uptake of DNA could allow V. fischeri cells to acquire new genetic information or utilize DNA as a nutrient source. Establishing a role for competence in the squid-vibrio symbiosis would not only broaden our understanding of this specific relationship. The mechanical aspects of competence are fairly well understood and characterized in a variety of species, however much less is known about the in vivo significance of DNA uptake.
|
