TY - JOUR
T1 - Biochemical and molecular characterization of δ-endotoxins in Bacillus thuringiensis
AU - Rosas-García, N. M.
AU - Sánchez-Varela, A.
AU - Villegas-Mendoza, J. M.
N1 - Funding Information:
This work received financial support from the Secretaría de Investigación y Posgrado del Instituto Politécnico Nacional, projects 20070138, and 20080218, and the Comisión de Operación y Fomento de Actividades Académicas del Instituto Politécnico Nacional (COFAA-IPN).
PY - 2009
Y1 - 2009
N2 - The δ-endotoxins (δ-ETX) of four native strains (RT7, RT19, RT25, and RT25), and one reference strain (4L1) of Bacillus thuringiensis were biochemically and molecularly characterized to determine their potential toxic activity against lepidopteran larvae. Crystals of δ-ETX were purified through a two-phase system to determine their morphology, molar mass, solubility, and resistance to proteinases. Toxic activity and cry gene content were also determined. Crystals from native strains exhibited polyhedral, irregular and cuboidal shapes, while those from 4L1 were bipyramidal. Seven proteins with estimated molar mass ≈30-134 kDa were detected as the main components of the native δ-ETX. Only crystals from 4L1, RT24, and RT25 underwend complete solubilization at pH >12.0. Crystals from all strains produced trypsin-resistant peptides. None of the cry genes associated with toxicity in lepidopterans (cryl, cry2, cry9) was found in the native strains; however, 4L1 strain harbors cryl and cry2 genes. Strains RT19 and RT25 caused significant mortality against Trichoplusia ni larvae with partial solubilization at pH 10, strain 4L1 caused 100 % mortality. Toxicity of native strains may come from a novel cry gene.
AB - The δ-endotoxins (δ-ETX) of four native strains (RT7, RT19, RT25, and RT25), and one reference strain (4L1) of Bacillus thuringiensis were biochemically and molecularly characterized to determine their potential toxic activity against lepidopteran larvae. Crystals of δ-ETX were purified through a two-phase system to determine their morphology, molar mass, solubility, and resistance to proteinases. Toxic activity and cry gene content were also determined. Crystals from native strains exhibited polyhedral, irregular and cuboidal shapes, while those from 4L1 were bipyramidal. Seven proteins with estimated molar mass ≈30-134 kDa were detected as the main components of the native δ-ETX. Only crystals from 4L1, RT24, and RT25 underwend complete solubilization at pH >12.0. Crystals from all strains produced trypsin-resistant peptides. None of the cry genes associated with toxicity in lepidopterans (cryl, cry2, cry9) was found in the native strains; however, 4L1 strain harbors cryl and cry2 genes. Strains RT19 and RT25 caused significant mortality against Trichoplusia ni larvae with partial solubilization at pH 10, strain 4L1 caused 100 % mortality. Toxicity of native strains may come from a novel cry gene.
UR - http://www.scopus.com/inward/record.url?scp=77950875802&partnerID=8YFLogxK
U2 - 10.1007/s12223-009-0069-7
DO - 10.1007/s12223-009-0069-7
M3 - Artículo
C2 - 20140714
SN - 0015-5632
VL - 54
SP - 487
EP - 492
JO - Folia Microbiologica
JF - Folia Microbiologica
IS - 6
ER -