title: Characterization of a new Bacillus thuringiensis isolate highly active against Cochylis hospes.
abstract: A new bacterial isolate, 00-50-5, from sunflower head extracts was identified as Bacillus thuringiensis (Bt) according to its morphology. Bt isolate 00-50-5 was highly active against the banded sunflower moth (BSM), Cochylis hospes Walsingham. A sodium dodecylsulfate-polyacrylamide gel electrophoresis (SDS-PAGE) 4-15% gradient gel of whole strain protein of 00-50-5 revealed six proteins with molecular masses (Mr) of 133, 80, 60, 27, 15, and 14 kDa. SDS-PAGE of pH 4.2-precipitated proteins (PP) or activated proteins formed by adding the BSM larval gut protease at 1:50 (wt/wt, protease/PP) showed five bands, including two major proteins of Mr 60 kDa and 27 kDa, and three small peptides of Mr 15, 13, and 7 kDa. The BSM larval gut protease was able to completely digest the proteins when present at a high ratio (10:1, wt/wt, protease/PP). The 60- and 27-kDa proteins could be digested by subtilisin Carlsberg at ratios of 1:50 or 1:1 (wt/wt, protease/PP), but neither BSM larval gut protease nor trypsin was effective at the same ratios. Three small peptides of Mr 15, 13, and 7 kDa were digested by the gut protease at a ratio of 1:1 (wt/wt). The N-terminal sequence of 1-31 amino acid residues for the 27-kDa protein showed 96.7% homology to a 31-amino acid fragment from camelysin, a protease from B. cereus, indicating that the 27-kDa protein may be a camelysin and a novel active protein against BSM.
authors.affiliation: U. S. Department of Agriculture, Agricultural Research Service, P.O. Box 5677, Fargo, ND 58105, USA. cheng.bai@und.nodak.edu
authors.forename: Cheng
authors.initials: C
authors.lastname: Bai
authors.forename: Brady A
authors.initials: BA
authors.lastname: Vick
authors.forename: Shu-Xia
authors.initials: SX
authors.lastname: Yi
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001413:Bacillus thuringiensis / Q000737:chemistry / Q000235:genetics / Q000472:pathogenicity*; D001426:Bacterial Proteins / Q000737:chemistry* / Q000302:isolation & purification / Q000633:toxicity; D001427:Bacterial Toxins / Q000737:chemistry* / Q000302:isolation & purification / Q000633:toxicity; D004591:Electrophoresis, Polyacrylamide Gel; D010450:Endopeptidases; D006368:Helianthus / Q000382:microbiology; D007814:Larva / Q000187:drug effects / Q000201:enzymology; D007928:Lethal Dose 50; D008666:Metalloendopeptidases / Q000737:chemistry; D008969:Molecular Sequence Data; D009036:Moths / Q000187:drug effects / Q000201:enzymology / Q000382:microbiology*; D010446:Peptide Fragments / Q000302:isolation & purification; D012639:Seeds / Q000382:microbiology; D017386:Sequence Homology, Amino Acid; D012988:Soil Microbiology; D020860:Subtilisin
chemical_list: D001426:Bacterial Proteins; D001427:Bacterial Toxins; D010446:Peptide Fragments; D010450:Endopeptidases; D020860:Subtilisin; D008666:Metalloendopeptidases; C438729:camelysin