Discovery and characterization of Sip1A: A novel secreted protein from Bacillus thuringiensis with activity against coleopteran larvae.

Bioassay screening of Bacillus thuringiensis culture supernatants identified strain EG2158 as having larvicidal activity against Colorado potato beetle (Leptinotarsa decemlineata) larvae. Ion-exchange fractionation of the EG2158 culture supernatant resulted in the identification of a protein designated Sip1A (secreted insecticidal protein) of approximately 38 kDa having activity against Colorado potato beetle (CPB). An oligonucleotide probe based on the N-terminal sequence of the purified Sip1A protein was used to isolate the sip1A gene.

Interaction of two Bacillus thuringiensis delta-endotoxins with the digestive system of Lygus hesperus.

The active-toxin form of CrylAc (65 kDa) or Cry2Ab was fed to a non-susceptible insect, Lygus hesperus, in an artificial diet. Biochemical and immunocytochemical methods were used to determine the distribution of ingested toxin. The toxins did not elicit a feeding deterrent response.