Identification of Novel Components Influencing Colonization Factor Antigen I Expression in Enterotoxigenic XXXX .

@entity3264 @entity368 @entity3157 @entity6186 @entity505 @entity3795 @entity3913 @entity3558 @entity7437 @entity413 @entity1063 @entity1577 @entity526
UNASSIGNED: Colonization factors (CFs) mediate early adhesion of Enterotoxigenic @entity526 (ETEC) in the small intestine. Environmental signals including bile, @entity413 , and contact with epithelial cells have previously been shown to modulate @entity1577 expression in a strain dependent manner. To identify novel components modulating @entity1577 surface expression, 20 components relevant to the intestinal environment were selected for evaluation. These included @entity3558 , @entity3157 , @entity1063 , @entity6186 , @entity505 sources, and cations. Effects of individual components on surface expression of the archetype @entity1577 , @entity3795 /I, were screened using a fractional factorial Hadamard matrix incorporating 24 growth conditions. As most CFs agglutinate erythrocytes, surface expression was evaluated by @entity3913 resistant hemagglutination. Seven components, including porcine gastric @entity3558 , @entity6186 , @entity3264 , and @entity413 were found to induce @entity3795 /I surface expression in vitro in a minimal media while five others were inhibitory, including @entity368 and @entity7437 . To further explore the effect of components positively influencing @entity3795 /I surface expression, a response surface methodology (RSM) was designed incorporating 36 growth conditions. The optimum concentration for each component was identified, thereby generating a novel culture media, SP1, for @entity3795 /I expression. CFs closely related to @entity3795 /I, including CS4 and CS14 were similarly induced in SP1 media. Other epidemiologically relevant CFs were also induced when compared to the level obtained in minimal media. These results indicate that although @entity1577 surface expression is complex and highly variable among strains, the @entity1577 response can be predicted for closely related strains. A novel culture media inducing CFs in the CF5a group was successfully identified. In addition, @entity3558 was found to positively influence @entity1577 expression in strains expressing either @entity3795 /I or CS1 and CS3, and may function as a common environmental cue.
