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Full-Text Articles in Life Sciences
When The Pandemic Opts For The Lockdown: Secretion System Evolution In The Cholera Bacterium, Francis J. Santoriello, Stefan Pukatzki
When The Pandemic Opts For The Lockdown: Secretion System Evolution In The Cholera Bacterium, Francis J. Santoriello, Stefan Pukatzki
Publications and Research
Vibrio cholerae, the causative agent of the diarrheal disease cholera, is a microbe capable of inhabiting two different ecosystems: chitinous surfaces in brackish, estuarine waters and the epithelial lining of the human gastrointestinal tract. V. cholerae defends against competitive microorganisms with a contact-dependent, contractile killing machine called the type VI secretion system (T6SS) in each of these niches. The T6SS resembles an inverted T4 bacteriophage tail and is used to deliver toxic effector proteins into neighboring cells. Pandemic strains of V. cholerae encode a unique set of T6SS effector proteins, which may play a role in pathogenesis or pandemic …
Characterization Of Β-Lactam Resistant Pandemic Serotypes Of Vibrio Cholerae Isolated From Ships' Ballast Tanks And Coastal Waters, Amanda Lynn Goodrich
Characterization Of Β-Lactam Resistant Pandemic Serotypes Of Vibrio Cholerae Isolated From Ships' Ballast Tanks And Coastal Waters, Amanda Lynn Goodrich
OES Theses and Dissertations
Vibrio cholerae serotypes 01 and 0139 are responsible for world-wide epidemics of cholera. These pandemic causing strains must possess genes that encode for the cholera toxin (CTX) and toxin co-regulated pili (TCP) in order to infect their hosts. In this study, 284 isolates of Vibrio cholerae from ballast and coastal waters were serotyped, with 11 % testing positive for serotype 01 and 21 % testing positive for serotype 0139. PCR assays were used to detect the presence of ctxA and tcpA genes in all positive isolates, none of which contained ctxA while 2% of the isolates contained tcpA. The 01 …
Requirements For Vibrio Cholerae Hapr Binding And Transcriptional Repression At The Hapr Promoter Are Distinct From Those At The Apha Promoter, Wei Lin, Gabriela Kovacikova, Karen Skorupski
Requirements For Vibrio Cholerae Hapr Binding And Transcriptional Repression At The Hapr Promoter Are Distinct From Those At The Apha Promoter, Wei Lin, Gabriela Kovacikova, Karen Skorupski
Dartmouth Scholarship
Virulence gene expression in certain strains of Vibrio cholerae is regulated in response to cell density by a quorum-sensing cascade that influences the levels of the LuxR homolog HapR through small regulatory RNAs that control the stability of its message. At high cell density, HapR represses the expression of the gene encoding the virulence gene activator AphA by binding to a site between −85 and −58 in the aphA promoter. We show here that a second binding site for HapR lies within the hapR promoter from which it functions to repress its own transcription. This site, as determined by gel …
Identification Of A Tcpc-Tcpq Outer Membrane Complex Involved In The Biogenesis Of The Toxin-Coregulated Pilus Of Vibrio Cholerae, Niranjan Bose, Ronald K. Taylor
Identification Of A Tcpc-Tcpq Outer Membrane Complex Involved In The Biogenesis Of The Toxin-Coregulated Pilus Of Vibrio Cholerae, Niranjan Bose, Ronald K. Taylor
Dartmouth Scholarship
The toxin-coregulated pilus (TCP) of Vibrio cholerae and the soluble TcpF protein that is secreted via the TCP biogenesis apparatus are essential for intestinal colonization. The TCP biogenesis apparatus is composed of at least nine proteins but is largely uncharacterized. TcpC is an outer membrane lipoprotein required for TCP biogenesis that is a member of the secretin protein superfamily. In the present study, analysis of TcpC in a series of strains deficient in each of the TCP biogenesis proteins revealed that TcpC was absent specifically in a tcpQ mutant. TcpQ is a predicted periplasmic protein required for TCP biogenesis. Fractionation …
Mechanism Of Toxt-Dependent Transcriptional Activation At The Vibrio Cholerae Tcpa Promoter, Robin R. Hulbert, Ronald K. Taylor
Mechanism Of Toxt-Dependent Transcriptional Activation At The Vibrio Cholerae Tcpa Promoter, Robin R. Hulbert, Ronald K. Taylor
Dartmouth Scholarship
The AraC homolog ToxT coordinately regulates virulence gene expression in Vibrio cholerae. ToxT is required for transcriptional activation of the genes encoding cholera toxin and the toxin coregulated pilus, among others. In this work we focused on the interaction of ToxT with the tcpA promoter and investigated the mechanism of ToxT-dependent transcriptional activation at tcpA. Deletion analysis showed that a region from −95 to +2 was sufficient for ToxT binding and activation, both of which were simultaneously lost when the deletion was extended to −63. A collection of point mutations generated by error-prone PCR revealed two small regions required …