تشخيص و اندازه گيري بتااگزوتوكسين در جدايه هاي ايراني

Determination of 13-exotoxin in Iranian Isolates of Bacillus thuringiensis

Twelve Iranian isolates of B. thuringiensis were evaluated for Beta-exotoxin using combination of bioassay and HPLC methods. Bioassay results on 4 days old larvae of Helicoverpa armigera showed the existence of a mortality factor, which can be Beta-exotoxin, in some autoclaved supernatant of isolates (with no spores and crystals). To verify these results, the Beta-exotoxin was measured in each isolate using HPLC method. The results indicated that the concentrated supernatant of isolates Krm23, Kn4, 3R and 41 contained (Beta-exotoxin. Isolates Krm23 and 3R had the lowest (7.37 miug/ml) and highest (294,5 pg/ml) amounts of Beta-exotoxin, respectively. Comparison of bioassay results with 3-exotoxin analyzed by HPLC showed that measured quantities of p-exotoxin were confirmed by the mortality percentage of Helicoverpa armigera.