DETECTION OF GENE-EXPRESSION IN ENTEROTOXIGENIC ESCHERICHIA-COLI BY HYBRIDIZATION OF RNA WITH A DIGOXIGENIN-LABELED DNA-PROBE

A simple method for microbial gene expression analysis in enterotoxige nic Escherichia coli strains is described, which combines RNA extracti on and probing with a digoxigenin-labelled DNA probe coding for heat l abile (LT) enterotoxin. We used this method to detect the expression o f the elt gene coding for LT toxin production in Escherichia coli stra in H10407. This method detected the expression of the elt gene in 10(8 ) cells in exponential phase culture and allowed to follow the variati ons of RNA concentrations as a function of time. This method might be useful as powerful tool for study expression of the genes in microorga nisms released in the environment e.g. pathogenic genes, degradative g enes.