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Specificity of Bacillus thuringiensis var. colmeri insecticidal delta-endotoxin is determined by differential proteolytic processing of the protoxin by larval gut proteases.
Eur J Biochem. 1986 May 02; 156(3):531-40.EJ

Abstract

The native crystal delta-endotoxin produced by Bacillus thuringiensis var. colmeri, serotype 21, is toxic to both lepidopteran (Pieris brassicae) and dipteran (Aedes aegypti) larvae. Solubilization of the crystal delta-endotoxin in alkaline reducing conditions and activation with trypsin and gut extracts from susceptible insects yielded a preparation whose toxicity could be assayed in vitro against a range of insect cell lines. After activation with Aedes aegypti gut extract the preparation was toxic to all of the mosquito cell lines but only one lepidopteran line (Spodoptera frugiperda), whereas an activated preparation produced by treatment with P. brassicae gut enzymes or trypsin was toxic only to lepidopteran cell lines. These in vitro results were paralleled by the results of in vivo bioassays. Gel electrophoretic analysis of the products of these different activation regimes suggested that a 130-kDa protoxin in the native crystal is converted to a 55-kDa lepidopteran-specific toxin by trypsin or P. brassicae enzymes and to a 52-kDa dipteran toxin by A. aegypti enzymes. Two-step activation of the 130-kDa protoxin by successive treatment with trypsin and A. aegypti enzymes further suggested that the 52-kDa dipteran toxin is derived from the 55-kDa lepidopteran toxin by enzymes specific to the mosquito gut. Confirmation of this suggestion was obtained by peptide mapping of these two polypeptides. The native crystal 130 kDa delta-endotoxin and the two insect-specific toxins all cross-reacted with antiserum to B. thuringiensis var. kurstaki P1 lepidopteran toxin. Preincubation of the two activated colmeri toxins with P1 antiserum neutralized their cytotoxicity to both lepidopteran and dipteran cell lines.

Authors

No affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Comparative Study
Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

3009187

Citation

Haider, M Z., et al. "Specificity of Bacillus Thuringiensis Var. Colmeri Insecticidal Delta-endotoxin Is Determined By Differential Proteolytic Processing of the Protoxin By Larval Gut Proteases." European Journal of Biochemistry, vol. 156, no. 3, 1986, pp. 531-40.
Haider MZ, Knowles BH, Ellar DJ. Specificity of Bacillus thuringiensis var. colmeri insecticidal delta-endotoxin is determined by differential proteolytic processing of the protoxin by larval gut proteases. Eur J Biochem. 1986;156(3):531-40.
Haider, M. Z., Knowles, B. H., & Ellar, D. J. (1986). Specificity of Bacillus thuringiensis var. colmeri insecticidal delta-endotoxin is determined by differential proteolytic processing of the protoxin by larval gut proteases. European Journal of Biochemistry, 156(3), 531-40.
Haider MZ, Knowles BH, Ellar DJ. Specificity of Bacillus Thuringiensis Var. Colmeri Insecticidal Delta-endotoxin Is Determined By Differential Proteolytic Processing of the Protoxin By Larval Gut Proteases. Eur J Biochem. 1986 May 2;156(3):531-40. PubMed PMID: 3009187.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Specificity of Bacillus thuringiensis var. colmeri insecticidal delta-endotoxin is determined by differential proteolytic processing of the protoxin by larval gut proteases. AU - Haider,M Z, AU - Knowles,B H, AU - Ellar,D J, PY - 1986/5/2/pubmed PY - 2000/3/11/medline PY - 1986/5/2/entrez SP - 531 EP - 40 JF - European journal of biochemistry JO - Eur J Biochem VL - 156 IS - 3 N2 - The native crystal delta-endotoxin produced by Bacillus thuringiensis var. colmeri, serotype 21, is toxic to both lepidopteran (Pieris brassicae) and dipteran (Aedes aegypti) larvae. Solubilization of the crystal delta-endotoxin in alkaline reducing conditions and activation with trypsin and gut extracts from susceptible insects yielded a preparation whose toxicity could be assayed in vitro against a range of insect cell lines. After activation with Aedes aegypti gut extract the preparation was toxic to all of the mosquito cell lines but only one lepidopteran line (Spodoptera frugiperda), whereas an activated preparation produced by treatment with P. brassicae gut enzymes or trypsin was toxic only to lepidopteran cell lines. These in vitro results were paralleled by the results of in vivo bioassays. Gel electrophoretic analysis of the products of these different activation regimes suggested that a 130-kDa protoxin in the native crystal is converted to a 55-kDa lepidopteran-specific toxin by trypsin or P. brassicae enzymes and to a 52-kDa dipteran toxin by A. aegypti enzymes. Two-step activation of the 130-kDa protoxin by successive treatment with trypsin and A. aegypti enzymes further suggested that the 52-kDa dipteran toxin is derived from the 55-kDa lepidopteran toxin by enzymes specific to the mosquito gut. Confirmation of this suggestion was obtained by peptide mapping of these two polypeptides. The native crystal 130 kDa delta-endotoxin and the two insect-specific toxins all cross-reacted with antiserum to B. thuringiensis var. kurstaki P1 lepidopteran toxin. Preincubation of the two activated colmeri toxins with P1 antiserum neutralized their cytotoxicity to both lepidopteran and dipteran cell lines. SN - 0014-2956 UR - https://www.unboundmedicine.com/medline/citation/3009187/Specificity_of_Bacillus_thuringiensis_var__colmeri_insecticidal_delta_endotoxin_is_determined_by_differential_proteolytic_processing_of_the_protoxin_by_larval_gut_proteases_ DB - PRIME DP - Unbound Medicine ER -