Biochemical, immunological and toxicological characteristics of the crystal proteins of Bacillus thuringiensis subsp. medellin
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Characterization of the insecticidal and hemolytic activity of solubilized crystal proteins of Bacillus thuringiensis subsp. medellin (Btmed) was performed and compared to solubilized crystal proteins of isolate 1884 of B. thuringiensis subsp. israelensis (Bti) and isolate PG-14 of B. thuringiensis subsp. morrisoni (Btm). In general, at acid pH values, solubilization of the Bt crystalline parasporal inclusions (CPI) was lower than at alkaline pH. The larvicidal activity demonstrated by the CPI of Btmed indicated that optimal solubilization of CPI takes place at a pH value of 11.3, in Bti at pH values from 5.03 to 11.3 and in Btm at pH values from 9.05 to 11.3. Hemolytical activity against sheep red blood cells was mainly found following extraction at pH 11.3 in all Bt strains tested. Polyacrylamide gel electrophoresis under denaturing conditions revealed that optima' solubilization of the CPI in all Bt strains takes place at alkaline pH values from 9.05 to 11.3. An enriched preparation of Btmed crystals was obtained, solubilized crystal proteins were separated on a size exclusion column (Sephacryl S-200). Three main protein peaks were observed on the chromatogram. The first peak had two main proteins that migrate between 90 to 100 kDa. These proteins are apparently not common to other Bt strains isolated to date. The second and third peaks obtained from the size exclusion column yielded polypeptides of 68 and 28-30 kDa, respectively. Each peak independently showed toxicity against first instar Culex quinquefasciatus larvae. These results suggest that the 94 kDa protein is an important component of the Btmed toxins with the highest potency to kill mosquito larvae. Combinations of the fractions corresponding to the 68 and 30 kDa protein showed increased toxicity. When crystal proteins of Bti were tested with antisera raised independently against the three main protein fractions of Btmed, the only crystal protein that showed cross-reaction was the 28 kDa protein. These data suggest that Btmed could be an alternative bacterium for mosquito control programs in case that mosquito larval resistance emerges to Bti toxic proteins develops.
- ELKIN LÓPEZ, GUSTAVO LÓPEZ, SERGIO ORDUZ, Control of the cattle tick Boophilus microplus with Metarhizium anisopliae, laboratory and field studies. , Revista Colombiana de Entomología: Vol. 35 No. 1 (2009)
- ADRIANA ORTIZ, ALEJANDRO MADRIGAL, SERGIO ORDUZ, Behavior evaluation of the Atta cephalotes ants (Hymenoptera: Formicidae) during the contamination of the fungus garden with Trichoderma lignorum , Revista Colombiana de Entomología: Vol. 25 No. 2 (1999)
- FERNANDO VALLEJO, MIGUEL ANGEL MORÓN, SERGIO ORDUZ, First report and description of Phyllophaga obsoleta Blanchard (Coleoptera: Scarabaeoidea, Melolonthidae) in Colombia , Revista Colombiana de Entomología: Vol. 23 No. 1 (1997)
- NORA HELENA RESTREPO, MARÍA MERCEDES PATIÑO, SERGIO ORDUZ, THAIS DÍAZ, WILLIAM ROJAS, Characterization of genes coding for Bacillus thuringiensis ssp. medellin toxic proteins , Revista Colombiana de Entomología: Vol. 22 No. 1 (1996)
- THAIS DÍAZ, NORA RESTREPO, SERGIO ORDUZ, WILLIAM ROJAS, DISTRIBUTION AND ISOLATION OF Bacillus thuringiensis IN COLOMBIA , Revista Colombiana de Entomología: Vol. 19 No. 2 (1993)
- ELKIN LÓPEZ, MAGALLY ROMERO, ADRIANA ORTIZ, SERGIO ORDUZ, First report of Metarhizium anisopliae infecting queens of Atta cephalotes (Hymenoptera: Formicidae) from Colombia , Revista Colombiana de Entomología: Vol. 25 No. 1 (1999)
- CÉSAR SEGURA, FANNY GUZMÁN, MANUEL E. PATARROYO, SERGIO ORDUZ, Activation of the Bacillus thuringiensis subesp. medellin CryllBb protein by digestion with trypsin and Culex quinquefasciatus (Diptero: Culicidae) larval gut extracts , Revista Colombiana de Entomología: Vol. 24 No. 2 (1998)
- MAURICIO REALPE, SERGIO ORDUZ, Expression and Toxicity of Bacillus thuringiensis subesp. israelensis strains harbouring the gene encoding the main mosquitocidal 8-endotoxin from Bacillus thuringiensis subesp. medellin , Revista Colombiana de Entomología: Vol. 24 No. 2 (1998)
- NORA HELENA RESTREPO, MARÍA MERCEDES PATIÑO, SERGIO ORDUZ, Stability analysis of a recombinant bacterium with larvicidal activity , Revista Colombiana de Entomología: Vol. 22 No. 3 (1996)
- DIEGO VILLANUEVA, NUBIA VELÁSQUEZ, ESPERANZA RODRÍGUEZ, SERGIO ORDUZ, RAFAEL ARANGO, Molecular characterization of a Colombian Bacillus thuringiensis strain with activity against Tecia solanivora (Lepidoptera: Gelechiidae) , Revista Colombiana de Entomología: Vol. 35 No. 2 (2009)
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