title: Characterization of the cry1Ac17 gene from an indigenous strain of Bacillus thuringiensis subsp. kenyae.
abstract: An indigenously isolated strain of Bacillus thuringiensis subsp. kenyae exhibited toxicity against lepidopteran as well as dipteran insects. The lepidopteran active cry1Ac protoxin gene coding sequence of 3.5 kb from this strain was cloned into vector pET28a(+). However, it could not be expressed in commonly used Escherichia coli expression hosts, BL21(DE3) and BL21(DE3)pLysS. This gene is classified as cry1Ac17 in the B. thuringiensis toxic nomenclature database. The coding sequence of this gene revealed that it contains about 3% codons, which are not efficiently translated by these expression hosts. Hence, this gene was expressed in a modified expression host, Epicurian coli BL21-Codonplus (DE3)-RIL. The expression of gene yielded a 130-kDa Cry1Ac17 protein. The protein was purified and its toxicity was tested against economically important insect pests, viz., Helicoverpa armigera and Spodoptera litura. LC(50) values obtained against these insects were 0.1 ng/cm(3) and 1231 ng/cm(2), respectively. The higher toxicity of Cry1Ac17 protein, compared to other Cry1Ac proteins, toward these pests demonstrates the potential of this isolate as an important candidate in the integrated resistance management program in India.
authors.affiliation: Nuclear Agriculture and Biotechnology Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400 085, India.
authors.forename: Ramesh S
authors.initials: RS
authors.lastname: Hire
authors.forename: Ravindra D
authors.initials: RD
authors.lastname: Makde
authors.forename: Tanaji K
authors.initials: TK
authors.lastname: Dongre
authors.forename: Stanislaus F
authors.initials: SF
authors.lastname: D'souza
mesh_terms: D000818:Animals; D001413:Bacillus thuringiensis / Q000235:genetics*; D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics* / Q000302:isolation & purification / Q000633:toxicity*; D003001:Cloning, Molecular; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D004731:Endotoxins / Q000737:chemistry / Q000235:genetics* / Q000302:isolation & purification / Q000633:toxicity*; D004926:Escherichia coli / Q000235:genetics; D015870:Gene Expression; D006460:Hemolysin Proteins / Q000737:chemistry / Q000235:genetics* / Q000302:isolation & purification / Q000633:toxicity*; D007194:India; D007915:Lepidoptera / Q000187:drug effects*; D007928:Lethal Dose 50; D008969:Molecular Sequence Data; D008970:Molecular Weight; D017422:Sequence Analysis, DNA; D018411:Spodoptera / Q000187:drug effects*
chemical_list: D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins; D004269:DNA, Bacterial; D004731:Endotoxins; D006460:Hemolysin Proteins; C030956:insecticidal crystal protein, Bacillus Thuringiensis
references.citation: J Bacteriol. 1983 Apr;154(1):419-28
references.pmid: 6833183
references.citation: J Invertebr Pathol. 2005 Jan;88(1):83-6
references.pmid: 15707873
references.citation: J Biol Chem. 2002 Dec 6;277(49):46849-51
references.pmid: 12377776
references.citation: J Invertebr Pathol. 1998 Nov;72(3):336-7
references.pmid: 9784360
references.citation: Microbiol Mol Biol Rev. 1998 Sep;62(3):775-806
references.pmid: 9729609
references.citation: Microbiol Rev. 1989 Jun;53(2):242-55
references.pmid: 2666844
references.citation: Genes Dev. 1994 Nov 1;8(21):2641-52
references.pmid: 7958922
references.citation: J Invertebr Pathol. 1992 Jan;59(1):109-11
references.pmid: 1541846
references.citation: Appl Environ Microbiol. 1990 Aug;56(8):2480-3
references.pmid: 2403254
references.citation: J Invertebr Pathol. 2002 May;80(1):55-63
references.pmid: 12234543