Factors influencing lethality of Bacillus thuringiensis kurstaki toxin for eggs and larvae of Trichostrongylus colubriformis (Nematoda).
A toxin from Bacillus thuringiensis kurstaki was lethal to eggs and first- and second-stage larvae of the ruminant nematode Trichostrongylus colubriformis. Sheathed and exsheathed third-stage larvae were also killed by the toxin. However, susceptibility of the ova to the toxin decreased after several hours of development. Heating at 65 C for 1 hr or freezing at 0 C for 3 mo did not affect stability of the toxin. Ovicidal activity of the toxin was not altered by treatment with 13 microbial or mammalian enzymes, but toxicity was reduced by the antibiotics streptomycin or penicillin G and the enzyme inhibitor L-1-tosylamide 2-phenylethylchloromethyl ketone. Cuprous, ferrous, and zinc chlorides also inhibited the ovicidal activity of the toxin. Increased osmolarity of the assay media or solubilization of the toxin from pH 3 to 11 had no effect on toxicity for eggs. The membrane agents sodium vanadate and 4,4'-diisothiocyano-2,2' disulfonic acid stilbene increased (9-fold) and decreased (333-fold) toxicity, respectively. N-acetylneuraminic acid was the only tested sugar that reduced the toxicity of B. t. kurstaki.
Meadows
J
J
Animal Parasite Research Laboratory, Agricultural Research Service, U.S. Department of Agriculture, Auburn, Alabama 36830.
Gill
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Bone
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D017878:4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid; D012856:4-Acetamido-4'-isothiocyanatostilbene-2,2'-disulfonic Acid / Q000031:analogs & derivatives / Q000494:pharmacology; D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D000969:Antinematodal Agents / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D001413:Bacillus thuringiensis; D001427:Bacterial Toxins / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D002712:Chlorides / Q000494:pharmacology; D006358:Hot Temperature; D007928:Lethal Dose 50; D019158:N-Acetylneuraminic Acid; D009994:Osmolar Concentration; D010063:Ovum / Q000187:drug effects; D012794:Sialic Acids / Q000494:pharmacology; D014108:Tosylphenylalanyl Chloromethyl Ketone / Q000494:pharmacology; D014254:Trichostrongylus / Q000502:physiology*; D014638:Vanadates / Q000494:pharmacology
D000900:Anti-Bacterial Agents; D000969:Antinematodal Agents; C049673:Bacillus thuringiensis ovicidal toxin; D001427:Bacterial Toxins; D002712:Chlorides; D012794:Sialic Acids; D012856:4-Acetamido-4'-isothiocyanatostilbene-2,2'-disulfonic Acid; D014638:Vanadates; D014108:Tosylphenylalanyl Chloromethyl Ketone; D019158:N-Acetylneuraminic Acid; D017878:4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid