title: Variations in the mosquito larvicidal activities of toxins from Bacillus thuringiensis ssp. israelensis.
abstract: Comparing activities of purified toxins from Bacillus thuringiensis ssp. israelensis against larvae of seven mosquito species (vectors of tropical diseases) that belong to three genera, gleaned from the literature, disclosed highly significant variations in the levels of LC(50) as well as in the hierarchy of susceptibilities. Similar toxicity comparisons were performed between nine transgenic Gram-negative species, four of which are cyanobacterial, expressing various combinations of cry genes, cyt1Aa and p20, against larvae of four mosquito species as potential agents for biological control. Reasons for inconsistencies are listed and discussed. Standard conditions for toxin isolation and presentation to larvae are sought. A set of lyophilized powders prepared identically from six Escherichia coli clones expressing combinations of four genes displayed toxicities against larvae of three mosquito species, with levels that differed between them but with identical hierarchy.
authors.affiliation: Department of Life Sciences, Ben-Gurion University of the Negev, PO Box 653, Be'er Sheva 84105, Israel.
authors.forename: Zachariah Ngalo
authors.initials: ZN
authors.lastname: Otieno-Ayayo
authors.forename: Arieh
authors.initials: A
authors.lastname: Zaritsky
authors.forename: Margaret C
authors.initials: MC
authors.lastname: Wirth
authors.forename: Robert
authors.initials: R
authors.lastname: Manasherob
authors.forename: Vadim
authors.initials: V
authors.lastname: Khasdan
authors.forename: Rivka
authors.initials: R
authors.lastname: Cahan
authors.forename: Eitan
authors.initials: E
authors.lastname: Ben-Dov
mesh_terms: D000818:Animals; D001413:Bacillus thuringiensis / Q000737:chemistry* / Q000235:genetics; D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins / Q000235:genetics / Q000494:pharmacology*; D009033:Culicidae / Q000187:drug effects* / Q000382:microbiology; D004731:Endotoxins / Q000235:genetics / Q000494:pharmacology*; D004926:Escherichia coli / Q000235:genetics; D015870:Gene Expression; D006460:Hemolysin Proteins / Q000235:genetics / Q000494:pharmacology*; D007814:Larva / Q000187:drug effects / Q000382:microbiology; D007928:Lethal Dose 50; D030781:Organisms, Genetically Modified; D010572:Pest Control, Biological
chemical_list: D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins; D004731:Endotoxins; D006460:Hemolysin Proteins; C030956:insecticidal crystal protein, Bacillus Thuringiensis