title: Two Bacillus sphaericus binary toxins share the midgut receptor binding site: implications for resistance of Culex pipiens complex (Diptera: Culicidae) larvae.
abstract: This work demonstrates that Bin1 and Bin2 toxins, produced by Bacillus sphaericus strains IAB59 and 2362, respectively, share a binding site in midgut brush border membranes (BBMF) from Culex pipiens complex larvae. However, a colony selected with strain IAB59, displaying a resistance ratio of only 42-fold to IAB59, but a 162,000-fold resistance to strain 2362, was found to miss receptors for Bin2 in the BBMF. This correlates with results showing that Bin1, produced in strain IAB59, failed to bind specifically to BBMF from other colony highly resistant to strain 2362. Data indicate the loss of the BBMF bound receptor as a general mechanism of resistance to binary toxins in mosquito.
authors.affiliation: Departamento de Entomologia, Centro de Pesquisas Aggeu Magalhães-FIOCRUZ, Av. Moraes Rêgo s/n, Recife-PE 50670-420, Brazil. mhneves@cpqam.fiocruz.br
authors.forename: Maria Helena Neves Lobo
authors.initials: MH
authors.lastname: Silva-Filha
authors.forename: Cláudia Maria Fontes de
authors.initials: CM
authors.lastname: Oliveira
authors.forename: Lêda
authors.initials: L
authors.lastname: Regis
authors.forename: Zhiming
authors.initials: Z
authors.lastname: Yuan
authors.forename: Clara Martinez
authors.initials: CM
authors.lastname: Rico
authors.forename: Christina
authors.initials: C
authors.lastname: Nielsen-LeRoux
mesh_terms: D000818:Animals; D001407:Bacillus / Q000254:growth & development / Q000378:metabolism / Q000472:pathogenicity*; D001427:Bacterial Toxins / Q000737:chemistry / Q000378:metabolism* / Q000494:pharmacology; D001665:Binding Sites; D001667:Binding, Competitive; D003465:Culex / Q000187:drug effects* / Q000254:growth & development; D007305:Insecticide Resistance; D007814:Larva / Q000187:drug effects; D008871:Microvilli / Q000378:metabolism; D010572:Pest Control, Biological; D011956:Receptors, Cell Surface / Q000378:metabolism*
chemical_list: D001427:Bacterial Toxins; D011956:Receptors, Cell Surface; C046134:binB protein, Bacillus sphaericus