DETECTION OF THE INDUCTION OF SALMONELLA ENTEROTOXIN GENE-EXPRESSION BY CONTACT WITH EPITHELIAL-CELLS WITH RT-PCR

All strains of Salmonella enterica investigated were found to carry th e Salmonella enterotoxin gene (stn) as determined by PCR and hybridiza tion studies. However, when using CHO-K1 cells for testing the toxicit y of the strains, not all strains showed a toxic effect (cell elongati on) on the cells or did so only at a low level. The cultivation of Sal monella in contact with epithelial cells (IEC-6) led to an increase in the production of toxin. The sin gene expression was detectable with the help of the RT-PCR after 3 h of incubation. The RNA of the strains was isolated, transcribed into cDNA (with MMLV-reverse transcriptase) and amplified using PCR. The PCR products were separated electrophore tically using a polyacrylamide gel and detected by silver staining.