Sigma factor expression in E. coli environmental isolates
Water quality is critical for a many human activities. With respect to recreational water, a particular type of water source, there are often relatively high levels of microbial contamination in relation to other types of water sources (e.g., drinking water). E. coli is used as a microbial indicator for water quality because E. coli accumulation is positively correlated with fecal contamination. It is recognized that this current approach, however, is not fully protective of the health of the public using beaches. E. coli strains differ enormously in pathogenic potential as only few strains carrying disease-causing genetic determinants (e.g., strain O157:H7). This study will be taken place to examine the differences in genetic composition and gene expression between E. coli laboratory strain and environmental strains. Well-understood sigma factor genes will be employed as model genes to operate this study.