Identification of genetic interactions during Streptococcus gordonii biofilm formation
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Abstract
Plaque or biofilm is characterized by sessile growth on inert or biologically active surfaces. The complicated multistep developmental process of oral biofilm formation involves the interactions between this saliva-conditioned film (the acquired enamel pellicle) and the early bacterial colonizers, such as viridans streptococci (including S. gordonii).
Communication is a key element in successful organizations. Quorum sensing is the ability of bacteria to communicate with another. The purpose of this study was to use these biofilm-defective mutants, through a second mutagenesis, to identify genetic interactions; which occur during this transition, by identifying suppressor mutants of transcriptional fusions.
After the second mutagenesis, the site of Tn4001 transposition was determined for two of the double mutants. The double mutant, #16 (derived from S. gordonii adcR::Tn917-lac) was determined to have a Tn4001 insertion within comA, a component of the com operon in S. gordonii. Com AB encodes an ABC-type export permease that cleaves the product of comC to generate a peptide pheromone, competence-stimulating factor (esp). Another double mutant, #18 (derived from S. gordoniifruK::Tn917-lac) was determined to have Tn4001 insertion was within a gene encoding a putative lipoprotein and immediately adjacent to genes involved in glycerol metabolism and an X-prolyl dipeptidyl peptidase.
Although the insertions of Tn4001 have been found in two double mutants, they still have to be clearly verified through further sequence analysis. Future studies should examine methods to increase the induction of this gene for identifying the gene's function.
Description
Thesis (M.S.D.)--Boston University, Henry M. Goldman School of Dental Medicine, 2004 (Pediatric Dentistry).
Includes bibliographical references (leaves 47-57).
Includes bibliographical references (leaves 47-57).
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This work is being made available in OpenBU by permission of its author, and is available for research purposes only. All rights are reserved to the author.