Clifford W. Houston

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By using a mini-transposon, we obtained two mutated strains of a diarrheal isolate, SSU, of Aeromonas hydrophila that exhibited a 50 to 53% reduction in the hemolytic activity and 83 to 87% less cytotoxic activity associated with the cytotoxic enterotoxin (Act). Act is a potent virulence factor of A. hydrophila and has been shown to contribute significantly(More)
The structural gene and regulatory element for a cytolytic enterotoxin of a diarrheal isolate, SSU, of Aeromonas hydrophila was cloned and its DNA sequence was determined. A complementary, mixed synthetic oligonucleotide based on the first 10 NH2-terminal amino acid residues of the Aeromonas cytolytic enterotoxin was used as a probe to screen a genomic(More)
An aerolysin-related cytotoxic enterotoxin (Act) of Aeromonas hydrophila possesses multiple biological activities, which include its ability to lyse red blood cells, destroy tissue culture cell lines, evoke a fluid secretory response in ligated intestinal loop models, and induce lethality in mice. The role of Act in the virulence of the organism has been(More)
Aeromonas hydrophila is an emerging human pathogen that leads to gastroenteritis and other invasive diseases. By using a murine peritoneal culture (MPC) model, we identified via restriction fragment differential display PCR (RFDDPCR) five genes of A. hydrophila that were differentially expressed under in vivo versus in vitro growth conditions. The gene(More)
Cholera and salmonellosis are two diarrheal diseases in which intestinal tissue cyclic adenosine monophosphate (cAMP) concentrations are elevated. Investigations of each experimental disease were initiated to identify the specific intestinal cells containing the elevated cAMP. Epithelial cells were eluted from the mucosa of infected and control intestinal(More)
Transposon and marker exchange mutagenesis were used to evaluate the role of Aeromonas cytotoxic enterotoxin (Act) in the pathogenesis of diarrheal diseases and deep wound infections. The transposon mutants were generated by random insertion of Tn5-751 in the chromosomal DNA of a diarrheal isolate SSU of Aeromonas hydrophila. Some of the transposon mutants(More)
A cytotoxic enterotoxin (Act) of Aeromonas hydrophila is an important virulence factor with hemolytic, cytotoxic and enterotoxic activities. In this report, we demonstrated Act rapidly mobilized calcium from intracellular stores and evoked influx of calcium from the extracellular milieu in macrophages. A direct role of calcium in Act-induced prostaglandin(More)
A gene encoding the cytotoxic enterotoxin (Act) from Aeromonas hydrophila was hyperexpressed with the pET, pTRX, and pGEX vector systems. Maximum toxin yield was obtained with the pTRX vector. Approximately 40 to 60% of Act was in a soluble form with the pTRX and pET vector systems. The toxin protein was purified to homogeneity by a combination of ammonium(More)
Multiple HindIII-restriction fragments of Salmonella typhimurium and Salmonella typhi chromosomal DNA exhibited homology with the heat-labile enterotoxin (LT1) gene of Escherichia coli as determined by Southern blot analysis. A 9.4 kb HindIII restriction fragment identified in S. typhimurium and S. typhi chromosomal DNA reacted with both eltA and eltB gene(More)