||Characterization of the Mammalian Toxicity of the Crystal Polypeptides of 'Bacillus thuringiensis' subsp. 'Israelensis'.
Mayes, M. E. ;
Held, G. A. ;
Lau, C. ;
Seely, J. C. ;
Roe, R. M. ;
||Health Effects Research Lab., Research Triangle Park, NC. ;North Carolina State Univ. at Raleigh. ;Northrop Services, Inc./Environmental Sciences, Research Triangle Park, NC. ;National Inst. of Environmental Health Sciences, Research Triangle Park, NC.
||EPA/600/J-89/271; PHS-ES-07046 ;PHS-ES-00044;
Bacillus thuringiensis ;
Affinity chromatography ;
Lethal dose 50
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Solubilized crystal polypeptide preparations of Bacillus thuringiensis subsp. israelensis (BTI) were fractionated by immunoaffinity chromatography using a bound monoclonal antibody formed against the 28K crystal polypeptide. The 28K polypeptide was confirmed to be hemolytic and to possess low mosquitocidal activity against Aedes aegypti larvae. By comparison, the 28K polypeptide was more potent than the solubilized BTI crystals in male Swiss Webster mice, as the LD50 values were (p<0.05) 0.77 and 2.33 mg protein/kg body wt, respectively. Acute administration of the 28K polypeptide (mg/kg,ip) produced severe hypothermia and bradycardia in the mouse. No evidence for cooperativity between the 28K and other crystal polypeptides was observed. Preliminary histological examination of the mouse hearts exposed to the 28K polypeptide did not reveal any specific lesion, suggesting that the deficient cardiac performance might be a secondary physiological response. The present results indicate that the 28K polypeptide is the mammalian toxic component of BTI crystals. (Copyright (c) Society of Toxicology.)