PHENOTYPIC AND COMPARATIVE ANALYSIS OF QUORUM SENSING MUTANTS IN VIBRIO PARAHAEMOLYTICUS
Date
2020-05
Authors
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Publisher
University of Delaware
Abstract
Quorum sensing is a type of bacterial cell-to-cell communication process using
extracellular signaling molecules called autoinducers that reflect cell density. Bacteria
respond to these autoinducers to detect changes in cell population and therefore alter
gene expression. Vibrio parahaemolyticus is an enteric pathogen that causes
gastroenteritis when consumed through raw or undercooked shellfish. We used V.
parahaemolyticus as our model organism to study the quorum sensing pathway. In the
V. parahaemolyticus quorum sensing pathway, at low cell density, quorum sensing
response regulator LuxO is phosphorylated and activates sigma factor 54, also known
as RpoN. Activated RpoN recruits RNA polymerase to initiate transcription of the five
small quorum regulatory RNAs (qrr1-qrr5). The Qrr sRNAs post-transcriptionally
stabilize aphA and degrade opaR mRNA transcripts. OpaR is the quorum sensing high
cell density master regulator that has previously been shown to positively regulate the
virulence factor capsule polysaccharide (CPS).
We investigated the role of the Qrr sRNAs in CPS production, swimming, and
swarming motility. We examined six strains: wild type, ΔopaR, Δqrr null (no qrrs),
Δqrr1,3,4,5, Δqrr1,2,3,5 and Δqrr1,2,3,4, and determined that the Δqrr1,3,4,5 mutant
restored the expression of wild type CPS, swimming and swarming. This indicates that
qrr2 alone is capable of controlling the quorum sensing response in V.
parahaemolyticus
Description
Keywords
biological sciences, vibrio parahaemolyticus, quorum sensing