Two newly developed Bacillus sphaericus larvicidal formulations, VectoLex CG (corncob granules) and VectoLex WDG (water dispersible granules), were tested against Culex quinquefasciatus larvae in 4 highly polluted breeding sites in Thailand. VectoLex CG, applied at rates of 0.5-2 g/m2, gave satisfactory to complete control of late-instar larvae and pupae for up to 4 wk after treatment. The Vect...

Tcr Emr 7853, from Bacteroides thetaiotaomicron 7853, is a large chromosomal conjugative transposon which encodes resistance to both tetracycline (Tcr) and erythromycin (Emr). The erythromycin resistance gene of Tcr Emr 7853 did not cross-hybridize with ermF, the Emr gene found on previously studied Bacteroides regular and conjugative transposons. We have cloned and sequenced the erythromycin r...

Preparations of the larvicidal crystal from 46-h cultures of Bacillus sphaericus 2362 contain 125-, 110-, 63-, and 43-kilodalton (kDa) proteins (P. Baumann, B. M. Unterman, L. Baumann, A.H. Broadwell, S.J. Abbene, and R.D. Bowditch, J. Bacteriol. 163:738-747, 1985). The 63- and 43-kDa proteins, which have been purified, are not immunologically cross-reactive, and only the 43-kDa protein is toxi...

The effects of two widespread environmental pollutants, perchlorate and hexavalent chromium, were assessed on the efficacy of Bacillus thuringiensis subsp. israelensis (Bti) and Bacillus sphaericus (Bsph) against fourth instars of Culex quinquefasciatus Say (Diptera: Culicidae) in 24-h laboratory bioassays. Although 250 mg/liter perchlorate, a level somewhat higher than would be considered ecol...

Sacculi of Bacillus sphaericus CCM 2177 contain a secondary cell wall polymer which was completely extracted with 48% hydrofluoric acid. Nuclear magnetic resonance analysis showed that the polymer is composed of repeating units, as follows: -->3)-[4, 6-O-(1-carboxyethylidene)]( approximately 0. 5)-beta-D-ManpNAc-(1-->4)-beta-D-GlcpNAc-(1-->. The N-terminal part of the S-layer protein carrying S...

Two newly developed Bacillus sphaericus larvicidal formulations, VectoLex CG® (corncob granules) and VectoLex WDG® (water dispersible granules), were tested against Culex quinquefasciatus larvae in 4 highly polluted breeding sites in Thailand. VectoLex CG, applies at rates of 0.5-2 g/m2, gave satisfactory to complete control of late-instar larvae and pupae for up to 4 wk after treatment. The Ve...

The 2297 strain of Bacillus sphaericus produces a crystal of the Bin (binary) toxin that is approximately fourfold larger than that of strain 2362, the strain currently used in VectoLex, a commercial mosquito larvicide. Comparison of the regions downstream from the bin operon in these two strains showed that strain 2362 contained a 1.6-kb region with four orf genes not found in strain 2297. Ins...

The genetic diversity of 35 Bacillus sphaericus strains was analyzed by a newly developed multilocus sequence typing (MLST) scheme, toxin gene pool survey, and mosquito bioassay. The results demonstrated that strains assigned to the same sequence type (ST) had the same occurrence of toxin genes. Further sequence analysis revealed that toxic strains presented a nearly clonal population structure...