The Experts below are selected from a list of 1350 Experts worldwide ranked by ideXlab platform
John J. Mekalanos - One of the best experts on this subject based on the ideXlab platform.
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Vibrio cholerae TcpA affect colonization,
2016Co-Authors: Su L. Chiang, Ronald K. Taylor, Michael Koomey, John J. Mekalanos, Department Of MicrobiologyAbstract:Autoagglutination, and serum resistanc
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Single amino acid substitutions in the N-terminus of Vibrio cholerae TcpA affect colonization, Autoagglutination, and serum resistance
Molecular microbiology, 1995Co-Authors: Su L. Chiang, Ronald K. Taylor, Michael Koomey, John J. MekalanosAbstract:Summary The toxin-coregulated pilus (TCP) of Vibrio cholerae O1 is required for successful infection of the host. TcpA, the structural subunit of TCP, belongs to the type IV family of pilins, which includes the PilE pilin of Neisseria gonorrhoeae. Recently, single amino acid changes in the N-terminus of PilE were found to abolish Autoagglutination in gonococci. As type IV pilins demonstrate some similarities in function and amino acid sequence, site-directed mutagenesis and allelic exchange were used to create corresponding mutations in TcpA. All four mutant strains demonstrated Autoagglutination defects, and all were highly defective for colonization in the infant mouse model. These results support the previously proposed correlation between Autoagglutination and colonization. Finally, all four mutants are serum sensitive, indicating that TcpA plays a role in serum resistance, a phenotype previously attributed to TcpC. As the mutations have similar effects in N. gonorrhoeae and V. cholerae, our results support the idea that type IV pilins have similar functions in a variety of pathogenic bacteria.
Ece Karatan - One of the best experts on this subject based on the ideXlab platform.
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Effects Of Polyamines On Vibrio Cholerae Virulence Properties
PloS one, 2013Co-Authors: John Bradley Goforth, Nicholas Emmanuel Walter, Ece KaratanAbstract:Vibrio cholerae is the causative agent of the severe enteric disease cholera. To cause cholera the bacterium must be able to synthesize both cholera toxin (CT) and toxin-coregulated pilus (TCP) which mediates Autoagglutination and is required for colonization of the small intestine. Only a few environmental signals have been shown to regulate V. cholerae virulence gene expression. Polyamines, which are ubiquitous in nature, and have been implicated in regulating virulence gene expression in other bacteria, have not been extensively studied for their effect on V. cholerae virulence properties. The objective of this study was to test the effect of several polyamines that are abundant in the human intestine on V. cholerae virulence properties. All of the polyamines tested inhibited Autoagglutination of V. cholerae O1 classical strain in a concentration dependent manner. Putrescine and cadaverine decreased the synthesis of the major pilin subunit, TcpA, spermidine increased its production, and spermine had no effect. Putrescine and spermidine led to a decrease and increase, respectively, on the relative abundance of TCP found on the cell surface. Spermine led to a small reduction in cholera toxin synthesis whereas none of the other polyamines had an effect. The polyamines did not affect pili bundling morphology, but caused a small reduction in CTXφ transduction, indicating that the TCP present on the cell surface may not be fully functional. We hypothesize the inhibition of Autoagglutination is likely to be caused by the positively charged amine groups on the polyamines electrostatically disrupting the pili-pili interactions which mediate Autoagglutination. Our results implicate that polyamines may have a protective function against colonization of the small intestine by V. cholerae.
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Effects of Polyamines on Vibrio cholerae Virulence Properties
2012Co-Authors: John Bradley Goforth, Nicholas Emmanuel Walter, Ece KaratanAbstract:Vibrio cholerae is the causative agent of the severe enteric disease cholera. To cause cholera the bacterium must be able to synthesize both cholera toxin (CT) and toxin-coregulated pilus (TCP) which mediates Autoagglutination and is required for colonization of the small intestine. Only a few environmental signals have been shown to regulate V. cholerae virulence gene expression. Polyamines, which are ubiquitous in nature, and have been implicated in regulating virulence gene expression in other bacteria, have not been extensively studied for their effect on V. cholerae virulence properties. The objective of this study was to test the effect of several polyamines that are abundant in the human intestine on V. cholerae virulence properties. All of the polyamines tested inhibited Autoagglutination of V. cholerae O1 classical strain in a concentration dependent manner. Putrescine and cadaverine decreased the synthesis of the major pilin subunit, TcpA, spermidine increased its production, and spermine had no effect. Putrescine and spermidine led to a decrease and increase, respectively, on the relative abundance of TCP found on the cell surface. Spermine led to a small reduction in cholera toxin synthesis whereas none of the other polyamines had an effect. The polyamines did not affect pili bundling morphology, but caused a small reduction in CTXw transduction, indicating that the TCP present on the cell surface may not be fully functional. We hypothesize the inhibition of Autoagglutination is likely to be caused by the positively charged amine groups on the polyamines electrostatically disrupting the pili-pili interactions which mediate Autoagglutination. Our result
Su L. Chiang - One of the best experts on this subject based on the ideXlab platform.
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Vibrio cholerae TcpA affect colonization,
2016Co-Authors: Su L. Chiang, Ronald K. Taylor, Michael Koomey, John J. Mekalanos, Department Of MicrobiologyAbstract:Autoagglutination, and serum resistanc
-
Single amino acid substitutions in the N-terminus of Vibrio cholerae TcpA affect colonization, Autoagglutination, and serum resistance
Molecular microbiology, 1995Co-Authors: Su L. Chiang, Ronald K. Taylor, Michael Koomey, John J. MekalanosAbstract:Summary The toxin-coregulated pilus (TCP) of Vibrio cholerae O1 is required for successful infection of the host. TcpA, the structural subunit of TCP, belongs to the type IV family of pilins, which includes the PilE pilin of Neisseria gonorrhoeae. Recently, single amino acid changes in the N-terminus of PilE were found to abolish Autoagglutination in gonococci. As type IV pilins demonstrate some similarities in function and amino acid sequence, site-directed mutagenesis and allelic exchange were used to create corresponding mutations in TcpA. All four mutant strains demonstrated Autoagglutination defects, and all were highly defective for colonization in the infant mouse model. These results support the previously proposed correlation between Autoagglutination and colonization. Finally, all four mutants are serum sensitive, indicating that TcpA plays a role in serum resistance, a phenotype previously attributed to TcpC. As the mutations have similar effects in N. gonorrhoeae and V. cholerae, our results support the idea that type IV pilins have similar functions in a variety of pathogenic bacteria.
John Bradley Goforth - One of the best experts on this subject based on the ideXlab platform.
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Effects Of Polyamines On Vibrio Cholerae Virulence Properties
PloS one, 2013Co-Authors: John Bradley Goforth, Nicholas Emmanuel Walter, Ece KaratanAbstract:Vibrio cholerae is the causative agent of the severe enteric disease cholera. To cause cholera the bacterium must be able to synthesize both cholera toxin (CT) and toxin-coregulated pilus (TCP) which mediates Autoagglutination and is required for colonization of the small intestine. Only a few environmental signals have been shown to regulate V. cholerae virulence gene expression. Polyamines, which are ubiquitous in nature, and have been implicated in regulating virulence gene expression in other bacteria, have not been extensively studied for their effect on V. cholerae virulence properties. The objective of this study was to test the effect of several polyamines that are abundant in the human intestine on V. cholerae virulence properties. All of the polyamines tested inhibited Autoagglutination of V. cholerae O1 classical strain in a concentration dependent manner. Putrescine and cadaverine decreased the synthesis of the major pilin subunit, TcpA, spermidine increased its production, and spermine had no effect. Putrescine and spermidine led to a decrease and increase, respectively, on the relative abundance of TCP found on the cell surface. Spermine led to a small reduction in cholera toxin synthesis whereas none of the other polyamines had an effect. The polyamines did not affect pili bundling morphology, but caused a small reduction in CTXφ transduction, indicating that the TCP present on the cell surface may not be fully functional. We hypothesize the inhibition of Autoagglutination is likely to be caused by the positively charged amine groups on the polyamines electrostatically disrupting the pili-pili interactions which mediate Autoagglutination. Our results implicate that polyamines may have a protective function against colonization of the small intestine by V. cholerae.
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Effects of Polyamines on Vibrio cholerae Virulence Properties
2012Co-Authors: John Bradley Goforth, Nicholas Emmanuel Walter, Ece KaratanAbstract:Vibrio cholerae is the causative agent of the severe enteric disease cholera. To cause cholera the bacterium must be able to synthesize both cholera toxin (CT) and toxin-coregulated pilus (TCP) which mediates Autoagglutination and is required for colonization of the small intestine. Only a few environmental signals have been shown to regulate V. cholerae virulence gene expression. Polyamines, which are ubiquitous in nature, and have been implicated in regulating virulence gene expression in other bacteria, have not been extensively studied for their effect on V. cholerae virulence properties. The objective of this study was to test the effect of several polyamines that are abundant in the human intestine on V. cholerae virulence properties. All of the polyamines tested inhibited Autoagglutination of V. cholerae O1 classical strain in a concentration dependent manner. Putrescine and cadaverine decreased the synthesis of the major pilin subunit, TcpA, spermidine increased its production, and spermine had no effect. Putrescine and spermidine led to a decrease and increase, respectively, on the relative abundance of TCP found on the cell surface. Spermine led to a small reduction in cholera toxin synthesis whereas none of the other polyamines had an effect. The polyamines did not affect pili bundling morphology, but caused a small reduction in CTXw transduction, indicating that the TCP present on the cell surface may not be fully functional. We hypothesize the inhibition of Autoagglutination is likely to be caused by the positively charged amine groups on the polyamines electrostatically disrupting the pili-pili interactions which mediate Autoagglutination. Our result
Susan M Logan - One of the best experts on this subject based on the ideXlab platform.
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Changes in flagellin glycosylation affect Campylobacter Autoagglutination and virulence
Molecular Microbiology, 2006Co-Authors: Patricia Guerry, Cheryl P Ewing, Michael Schirm, Dawn Pattarini, Gary Majam, John F Kelly, Pierre Thibault, Maria Lorenzo, Susan M LoganAbstract:Summary Analysis of the complete flagellin glycosylation locus of Campylobacter jejuni strain 81–176 revealed a less complex genomic organization than the corresponding region in the genome strain, C. jejuni NCTC 11168. Twenty-four of the 45 genes found between Cj1293 and Cj1337 in NCTC 11168 are missing in 81–176. Mutation of six new genes, in addition to three previously reported, resulted in a non-motile phenotype, consistent with a role in synthesis of pseudaminic acid (PseAc) or transfer of PseAc to flagellin. Mutation of Cj1316c or pseA had been shown to result in loss of the acetamidino form of pseudaminic acid (PseAm). Mutation of a second gene also resulted in loss of PseAm, as well as a minor modification that appears to be PseAm extended with N-acetyl-glutamic acid. Previously described mutants in C. jejuni 81–176 and Campylobacter coli VC167 that produced flagella lacking PseAm or PseAc failed to autoagglutinate. This suggests that interactions between modifications on adjacent flagella filaments are required for Autoagglutination. Mutants (81–176) defective in Autoagglutination showed a modest reduction in adherence and invasion of INT407 cells. However, there was a qualitative difference in binding patterns to INT407 cells using GFP-labelled 81–176 and mutants lacking PseAm. A mutant lacking PseAm was attenuated in the ferret diarrhoeal disease model.
