scholarly journals Pathogenicity of Bacillus sphaericus to Larvae of the Mosquito, Culex pipiens

1980 ◽  
Vol 24 (2) ◽  
pp. 93-97
Author(s):  
Akira TSUCHIYAMA
Keyword(s):  
Culex Pipiens ◽  
Bacillus Sphaericus

The Introduction into Bacillus sphaericus of the Bacillus thuringiensis subsp. medellin cyt1Ab1 Gene Results in Higher Susceptibility of Resistant Mosquito Larva Populations to B. sphaericus

1998 ◽  
Vol 64 (10) ◽  
pp. 3910-3916 ◽  
Author(s):  
I. Thiéry ◽  
S. Hamon ◽  
A. Delécluse ◽  
S. Orduz
Keyword(s):  
Bacillus Thuringiensis ◽  
Culex Pipiens ◽  
Recombinant Strain ◽  
Mosquito Larva ◽  
Shuttle Vector ◽  
Bacillus Sphaericus ◽  
The Other ◽  
Binary Toxin ◽  
Gene Encoding ◽  
Flanking Sequences

ABSTRACT The fragment containing the gene encoding the cytolytic Cyt1Ab1 protein from Bacillus thuringiensis subsp.medellin and its flanking sequences (I. Thiery, A. Delécluse, M. C. Tamayo, and S. Orduz, Appl. Environ. Microbiol. 63:468–473, 1997) was introduced into Bacillus sphaericus toxic strains 2362, 2297, and Iab872 by electroporation with the shuttle vector pMK3. Only small amounts of the protein were produced in recombinant strains 2362 and Iab872. The protein was detected in these strains only by Western blotting and immunodetection with antibody raised against Cyt1Ab1 protein. Large amounts of Cyt1Ab1 protein were produced in B. sphaericus recombinant strain 2297, and there was an additional crystal, other than that of the binary toxin, within the exosporium. The production of the Cyt1Ab1 protein in addition to the binary toxin did not increase the larvicidal activity of theB. sphaericus recombinant strain against susceptible mosquito populations of Culex pipiens orAedes aegypti. However, it partially restored (10 to 20 times) susceptibility of the resistant mosquito populations of C. pipiens (SPHAE) and Culex quinquefasciatus (GeoR) to the binary toxin. The Cyt1Ab1 protein produced in recombinantB. thuringiensis SPL407(pcyt1Ab1) was synthesized in two types of crystal—one round and with various dense areas, surrounded by an envelope, and the other a regular cuboid crystal, very similar to that found in the B. sphaericus recombinant strain.

Ultrastructure of midgut events in the pathogenesis of Bacillus sphaericus strain SSII-1 infections of Culex pipiens quinquefasciatus larvae

1979 ◽  
Vol 25 (2) ◽  
pp. 178-184 ◽  
Author(s):  
Elizabeth West Davidson
Keyword(s):  
Culex Pipiens ◽  
Bacillus Sphaericus ◽  
Wall Layer ◽  
Peritrophic Membrane ◽  
Ground Substance ◽  
Outer Cell ◽  
Bacterial Cells ◽  
Culex Pipiens Quinquefasciatus ◽  
Larval Host ◽  
Cytoplasmic Ground Substance

The fate of Bacillus sphaericus strain SSII-1 cells ingested by Culex pipiens quinquefasciatus (= C. pipiens fatigans, C. fatigans, C. quinquefasciatus of authors; Diptera: Culicidae) larvae and the cytological events preceding death of the host were observed using electron microscopy. Bacillus sphaericus cells were digested rapidly in the anterior and central midgut. The outer cell wall layer and cytoplasmic ground substance disappeared soon after ingestion. Cytolysosomes became prominent in midgut cells as these cells gradually separated from one another. All bacteria, including B. sphaericus, were confined within the peritrophic membrane until after death of the host. Digestion by the larval host is confirmed as a possible mechanism for release of B. sphaericus toxin from the bacterial cells.

Comparative studies of the mosquito-larval toxin of Bacillus sphaericus SSII-1 and 1593

1979 ◽  
Vol 25 (11) ◽  
pp. 1227-1231 ◽  
Author(s):  
Paula Myers ◽  
Allan A. Yousten ◽  
Elizabeth W. Davidson
Keyword(s):  
Inclusion Body ◽  
Comparative Studies ◽  
Culex Pipiens ◽  
Strain Differences ◽  
Growth Cycle ◽  
Bacillus Sphaericus ◽  
Toxic Activity ◽  
Thin Sections ◽  
Culex Pipiens Quinquefasciatus

Two strains of Bacillus sphaericus, SSII-1 and 1593, were bioassayed for toxic activity against second-instar larvae of the mosquito Culex pipiens quinquefasciatus. It was found that strain 1593 developed a level of toxicity 3000 times that of strain SSII-1. Although the toxic activity of B. sphaericus SSII-1 was relatively unchanged throughout growth, an increase in activity of strain 1593 occurred as the bacteria began to sporulate. Strain differences were examined by (i) growth cycle experiments, (ii) bioassays of the toxicity of oligosporogenous mutants, and (iii) manganese limitation experiments. The toxin of strain 1593 was shown to be more stable than that of strain SSII-1. Unlike the spores of strain SSII-1, the spores of B. sphaericus 1593 were found to be highly toxic. Thin sections of SSII-1 or 1593 cells did not reveal the presence of any inclusion body that might be related to toxicity.

EFFICACY OF BACILLUS SPHAERICUS STRAIN 1593 AGAINST THE FOUR INSTARS OF LABORATORY REARED AND FIELD COLLECTED CULEX PIPIENS PIPIENS AND LABORATORY REARED CULEX SALINARIUS

1981 ◽  
Vol 113 (5) ◽  
pp. 379-386 ◽  
Author(s):  
Stephen P. Wraight ◽  
Daniel Molloy ◽  
Hugo Jamnback
Keyword(s):  
Culex Pipiens ◽  
Laboratory Tests ◽  
Bacillus Sphaericus ◽  
Culex Pipiens Pipiens ◽  
Culex Salinarius

AbstractCulex pipiens pipiens and C. salinarius were found equally susceptible in laboratory tests to Bacillus sphaericus strain 1593 with LC50 values for the four instars ranging between 20 and 137 ppb (approximately 820 and 5600 spores/ml). Tests against field collected C. p. pipiens larvae revealed a regularly decreasing susceptibility with increasing larval age, the first instars being between 2 and 5 times more susceptible than fourth instars. In contrast, no significant differences in the susceptibility of second, third, and fourth instars were found in tests of laboratory reared larvae.

scholarly journals Tightly Bound Binary Toxin in the Cell Wall of Bacillus sphaericus

2002 ◽  
Vol 68 (7) ◽  
pp. 3300-3307 ◽  
Author(s):  
Daniela Klein ◽  
Igor Uspensky ◽  
Sergei Braun
Keyword(s):  
Escherichia Coli ◽  
Cell Wall ◽  
Culex Pipiens ◽  
Bacillus Sphaericus ◽  
Binary Toxin ◽  
Crystal Formation ◽  
Treated Cell

ABSTRACT We have shown that urea-extracted cell wall of entomopathogenic Bacillus sphaericus 2297 and some other strains is a potent larvicide against Culex pipiens mosquitoes, with 50% lethal concentrations comparable to that of the well-known B. sphaericus binary toxin, with which it acts synergistically. The wall toxicity develops in B. sphaericus 2297 cultures during the late logarithmic stage, earlier than the appearance of the binary toxin crystal. It disappears with sporulation when the binary toxin activity reaches its peak. Disruption of the gene for the 42-kDa protein (P42) of the binary toxin abolishes both cell wall toxicity and crystal formation. However, the cell wall of B. sphaericus 2297, lacking P42, kills C. pipiens larvae when mixed with Escherichia coli cells expressing P42. Thus, the cell wall toxicity in strongly toxic B. sphaericus strains must be attributed to the presence in the cell wall of tightly bound 51-kDa (P51) and P42 binary toxin proteins. The synergism between binary toxin crystals and urea-treated cell wall preparations reflects suboptimal distribution of binary toxin subunits in both compartments. Binary toxin crystal is slightly deficient in P51, while cell wall is lacking in P42.

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