MODIFIED SPOT HYBRIDIZATION TEST USING BIOTINYLATED DNA-PROBE

A modification that simplifies the spot hybridization technique is des cribed for using biotinylated DNA probes. Plasmid EWD299 having LT gen e insert, labelled with biotin either by nick translation or using pho tobiotin was used as DNA probe for the specific detection of enterotox igenic Escherichia coli. A simple protocol has been described for easy lysis of test samples by boiling in distilled water followed by deter gent treatment and was found to be as efficient as the lysis using lys ozyme and protease. Three different solid supports namely DEAE-cellulo se paper, nitrocellulose paper and nylon membrane were also compared f or their suitability in this spot hybridization test. Nitrocellulose p aper was found to give better colour signal with the photobiotinylated DNA probe.