title: Transfer and expression of the mosquitocidal plasmid pBtoxis in Bacillus cereus group strains.
abstract: The toxicity of Bacillus thuringiensis subsp. israelensis to dipteran larvae (mosquitoes and black flies) depends on the presence of the pBtoxis plasmid. In this paper, two antibiotic resistance tagged pBtoxis were transferred by conjugation to other Bacillus cereus group strains. Among 15 potential recipients, only a lepidopteran active B. thuringiensis subspecies kurstaki and a B. cereus strain received the plasmid pBtoxis with a low transfer rate of about 10(-8) transconjugants/recipient. The resulting B. thuringiensis subspecies kurstaki transconjugant was active to both lepidopteran and dipteran targets and the B. cereus transconjugant was active against dipteran insects. Phase contrast microscopy showed that the B. cereus transconjugants could produce only round crystalline inclusion bodies while B. thuringiensis subspecies kurstaki transconjugant could produce both round and bipyramidal crystals during sporulation. SDS-PAGE revealed that all the major mosquitocidal proteins from pBtoxis could express in the two transconjugants, including Cry4Aa, Cry4Ba, Cry10Aa, Cry11Aa and Cyt1Aa. However, none of the experiment showed any indications of mobilising abilities of pBtoxis. The limited number of strains, which could receive and maintain pBtoxis using a conjugational helper plasmid, indicates a very narrow host range of the B. thuringiensis subsp. israelensis pBtoxis plasmid.
authors.affiliation: National Environmental Research Institute, 4000 Roskilde, Denmark.
authors.forename: Xiaomin
authors.initials: X
authors.lastname: Hu
authors.forename: Bjarne Munk
authors.initials: BM
authors.lastname: Hansen
authors.forename: Zhiming
authors.initials: Z
authors.lastname: Yuan
authors.forename: Jens Efsen
authors.initials: JE
authors.lastname: Johansen
authors.forename: Jørgen
authors.initials: J
authors.lastname: Eilenberg
authors.forename: Niels Bohse
authors.initials: NB
authors.lastname: Hendriksen
authors.forename: Lasse
authors.initials: L
authors.lastname: Smidt
authors.forename: Gert Bolander
authors.initials: GB
authors.lastname: Jensen
mesh_terms: D000818:Animals; D001409:Bacillus cereus / Q000166:cytology / Q000235:genetics* / Q000378:metabolism / Q000472:pathogenicity; D001413:Bacillus thuringiensis / Q000235:genetics; D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins / Q000096:biosynthesis* / Q000235:genetics*; D001427:Bacterial Toxins / Q000096:biosynthesis* / Q000235:genetics*; D003227:Conjugation, Genetic; D003465:Culex / Q000382:microbiology; D004591:Electrophoresis, Polyacrylamide Gel; D004731:Endotoxins / Q000096:biosynthesis* / Q000235:genetics*; D006460:Hemolysin Proteins; D002479:Inclusion Bodies / Q000378:metabolism; D010572:Pest Control, Biological; D010957:Plasmids; D016133:Polymerase Chain Reaction; D013171:Spores, Bacterial / Q000166:cytology / Q000378:metabolism; D014169:Transformation, Bacterial; D014774:Virulence / Q000235:genetics
chemical_list: D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins; D001427:Bacterial Toxins; D004731:Endotoxins; D006460:Hemolysin Proteins; C030956:insecticidal crystal protein, Bacillus Thuringiensis