An improved bioassay for the detection of Bacillus thuringiensis beta-exotoxin.
Some Bacillus thuringiensis strains secrete beta-exotoxin, which is an insecticidal, thermostable adenine nucleotide analogue. Discrepancies between detection of beta-exotoxin by high-performance liquid chromatography and insect bioassays have shown the importance of bioassays in the determination of beta-exotoxin production. With the aim of improving the fly beta-exotoxin bioassay, a range of fly diets were evaluated and the best performing diet was incorporated into a novel beta-exotoxin bioassay. The improved bioassay is characterised by good control pupation percentages, low variability, easy setup and monitoring. The bioassay allowed unambiguous differentiation between beta-exotoxin producing and non-producing strains, and is suitable for the routine screening of B. thuringiensis strains for beta-exotoxins.
University of the Witwatersrand, Johannesburg, Wits, South Africa.
Thomas Cameron
TC
Mac Innes
Gustav
G
Bouwer
D000241:Adenosine / Q000031:analogs & derivatives* / Q000302:isolation & purification / Q000633:toxicity; D000818:Animals; D001413:Bacillus thuringiensis / Q000378:metabolism*; D001681:Biological Assay / Q000379:methods*; D002851:Chromatography, High Pressure Liquid; D006793:Houseflies / Q000187:drug effects* / Q000382:microbiology / Q000502:physiology; D015203:Reproducibility of Results; D013400:Sugar Acids / Q000302:isolation & purification* / Q000633:toxicity
D013400:Sugar Acids; C068295:thuringiensin; D000241:Adenosine