scholarly journals Recombinant Strain of Bacillus thuringiensis Producing Cyt1A, Cry11B, and the Bacillus sphaericus Binary Toxin

2003 ◽  
Vol 69 (2) ◽  
pp. 1331-1334 ◽  
Author(s):  
Hyun-Woo Park ◽  
Dennis K. Bideshi ◽  
Brian A. Federici
Keyword(s):  
Bacillus Thuringiensis ◽  
Culex Quinquefasciatus ◽  
Recombinant Strain ◽  
Bacillus Sphaericus ◽  
Fourth Instar ◽  
Lethal Concentration ◽  
Binary Toxin

ABSTRACT A novel recombinant Bacillus thuringiensis subsp. israelensis strain that produces the B. sphaericus binary toxin, Cyt1Aa, and Cry11Ba is described. The toxicity of this strain (50% lethal concentration [LC50] = 1.7 ng/ml) against fourth-instar Culex quinquefasciatus was higher than that of B. thuringiensis subsp. israelensis IPS-82 (LC50 = 7.9 ng/ml) or B. sphaericus 2362 (LC50 = 12.6 ng/ml).

scholarly journals Improving the Insecticidal Activity against Resistant Culex quinquefasciatus Mosquitoes by Expression of Chitinase Gene chiAC in Bacillus sphaericus

2007 ◽  
Vol 73 (23) ◽  
pp. 7744-7746 ◽  
Author(s):  
Yajun Cai ◽  
Jianpin Yan ◽  
Xiaomin Hu ◽  
Bei Han ◽  
Zhiming Yuan
Keyword(s):  
Bacillus Thuringiensis ◽  
Insecticidal Activity ◽  
Culex Quinquefasciatus ◽  
Recombinant Strain ◽  
Bacillus Sphaericus ◽  
Chitinase Gene ◽  
Binary Toxin

ABSTRACT Expression of a chitinase gene, chiAC, from Bacillus thuringiensis in B. sphaericus 2297 using the binary toxin promoter yielded a recombinant strain that was 4,297-fold more toxic than strain 2297 against resistant Culex quinquefasciatus. These results show that this chitinase can synergize the toxicity of the binary toxin against mosquitoes and thus may be useful in managing mosquito resistance to B. 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.

scholarly journals A 1.1-Kilobase Region Downstream of the bin Operon in Bacillus sphaericus Strain 2362 Decreases Bin Yield and Crystal Size in Strain 2297

2008 ◽  
Vol 75 (3) ◽  
pp. 878-881 ◽  
Author(s):  
Hyun-Woo Park ◽  
Mujin Tang ◽  
Yuko Sakano ◽  
Brian A. Federici
Keyword(s):  
Homologous Recombination ◽  
Culex Quinquefasciatus ◽  
Crystal Size ◽  
Toxin Production ◽  
Bacillus Sphaericus ◽  
Fourth Instar ◽  
Binary Toxin ◽  
Size Characteristic

ABSTRACT 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. Insertion of a 1.1-kb portion of this region from strain 2362 by homologous recombination downstream from the bin operon in strain 2297 reduced Bin toxin production by 50 to 70% and toxicity to fourth-instar larvae of Culex quinquefasciatus by 68%. These results suggest that the 1.6-kb region downstream from the bin operon in B. sphaericus 2362 is responsible for the lower Bin yield and smaller crystal size characteristic of this strain.

scholarly journals Production of Cry11A and Cry11Ba Toxins in Bacillus sphaericus Confers Toxicity towards Aedes aegyptiand Resistant Culex Populations

1999 ◽  
Vol 65 (7) ◽  
pp. 3021-3026 ◽  
Author(s):  
Pascale Servant ◽  
Marie-Laure Rosso ◽  
Sylviane Hamon ◽  
Sandrine Poncet ◽  
Armelle Delécluse ◽  
...  
Keyword(s):  
Bacillus Thuringiensis ◽  
Culex Pipiens ◽  
Recombinant Strain ◽  
Bacillus Sphaericus ◽  
Binary Toxin ◽  
Protease Gene ◽  
Gene Encoding ◽  
In Vivo Recombination ◽  
Target Sites

ABSTRACT Cry11A from Bacillus thuringiensis subsp.israelensis and Cry11Ba from Bacillus thuringiensis subsp. jegathesan were introduced, separately and in combination, into the chromosome of Bacillus sphaericus 2297 by in vivo recombination. Two loci on theB. sphaericus chromosome were chosen as target sites for recombination: the binary toxin locus and the gene encoding the 36-kDa protease that may be responsible for the cleavage of the Mtx protein. Disruption of the protease gene did not increase the larvicidal activity of the recombinant strain against Aedes aegyptiand Culex pipiens. Synthesis of the Cry11A and Cry11Ba toxins made the recombinant strains toxic to A. aegyptilarvae to which the parental strain was not toxic. The strain containing Cry11Ba was more toxic than strains containing the added Cry11A or both Cry11A and Cry11Ba. The production of the two toxins together with the binary toxin did not significantly increase the toxicity of the recombinant strain to susceptible C. pipiens larvae. However, the production of Cry11A and/or Cry11Ba partially overcame the resistance of C. pipiens SPHAE andCulex quinquefasciatus GeoR to B. sphaericus strain 2297.

scholarly journals Conjugal Transfer of a Toxin-Coding Megaplasmid from Bacillus thuringiensis subsp. israelensis to Mosquitocidal Strains of Bacillus sphaericus

2006 ◽  
Vol 72 (3) ◽  
pp. 1766-1770 ◽  
Author(s):  
Katherine Gammon ◽  
Gareth W. Jones ◽  
Steven J. Hope ◽  
Cláudia M. F. de Oliveira ◽  
Lêda Regis ◽  
...  
Keyword(s):  
Bacillus Thuringiensis ◽  
Aedes Aegypti ◽  
Culex Quinquefasciatus ◽  
Vegetative Growth ◽  
Bacillus Sphaericus ◽  
Conjugal Transfer ◽  
Large Plasmid ◽  
Erythromycin Resistance ◽  
Plasmid Loss ◽  
The Stability

ABSTRACT Both Bacillus sphaericus and Bacillus thuringiensis subsp. israelensis produce mosquitocidal toxins during sporulation and are extensively used in the field for control of mosquito populations. All the known toxins of the latter organism are known to be encoded on a large plasmid, pBtoxis. In an attempt to combine the best properties of the two bacteria, an erythromycin resistance-marked pBtoxis plasmid was transferred to B. sphaericus by a mating technique. The resulting transconjugant bacteria were significantly more toxic to Aedes aegypti mosquitoes and were able to overcome resistance to B. sphaericus in a resistant colony of Culex quinquefasciatus, apparently due to the production of Cry11A but not Cry4A or Cry4B. The stability of the plasmid in the B. sphaericus host was moderate during vegetative growth, but segregational instability was observed, which led to substantial rates of plasmid loss during sporulation.

scholarly journals Analysis of toxicity on Bacillus sphaericus from amazonian soils to Anopheles darlingi and Culex quinquefasciatus larvae

2008 ◽  
Vol 38 (2) ◽  
pp. 255-262 ◽  
Author(s):  
Eleilza de Castro Litaiff ◽  
Wanderli Pedro Tadei ◽  
Jorge Ivan Rebelo Porto ◽  
Ila Maria de Aguiar Oliveira
Keyword(s):  
Larvicidal Activity ◽  
Culex Quinquefasciatus ◽  
Bacillus Sphaericus ◽  
Probit Analysis ◽  
Lethal Concentration ◽  
Anopheles Darlingi ◽  
Median Lethal Concentration ◽  
Standard Strain ◽  
Breeding Sites ◽  
High Effectiveness

Bioassays under laboratory conditions aiming to determine the larvicidal activity of Bacillus sphaericus were carried out on Anopheles darlingi and Culex quinquefasciatus. In order to estimate the toxicity through median lethal concentration (LC50) and the relative potency of the strains to B. sphaericus standard strain 2362, probit analysis was performed utilizing the POLO-PC program. The findings of LC50 pointed out high effectiveness on strains IB15 (0.040 ppm), IB19 and S1116 (0.048 ppm), IB16 (0.052 ppm) and S265 (0.057 ppm). Strain IB15 presented nearly 50% more potency than strain 2362 in bioassays conducted on A. darlingi. It was observed that IB16 and S1116 strains were the most powerful against C. quinquefasciatus, showing to be about 300-400% stronger than 2362 strain. The results show that laboratory conditioned evaluation can be an important way to select promising bacteria with entomopathogenic action on biolarvicides production for use on mosquitoes breeding sites.

scholarly journals Identification and Characterization of Three Previously Undescribed Crystal Proteins from Bacillus thuringiensis subsp.jegathesan

2013 ◽  
Vol 79 (11) ◽  
pp. 3364-3370 ◽  
Author(s):  
Yunjun Sun ◽  
Qiang Zhao ◽  
Liqiu Xia ◽  
Xuezhi Ding ◽  
Quanfang Hu ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Bacillus Thuringiensis ◽  
Recombinant Strain ◽  
Fourth Instar ◽  
Gene Promoters ◽  
Content Type ◽  
Crystal Proteins ◽  
Encoding Genes ◽  
Identification And Characterization

ABSTRACTThe total protoxin complement in the parasporal body of mosquitocidal strain,Bacillus thuringiensissubsp.jegathesan367, was determined by use of a polyacrylamide gel block coupled to mass spectrometry. A total of eight protoxins were identified from this strain, including five reported protoxins (Cry11Ba, Cry19Aa, Cry24Aa, Cry25Aa, and Cyt2Bb), as well as three previously undescribed (Cry30Ca, Cry60Aa, and Cry60Ba) in this isolate. It was interesting that the encoding genes of three new protoxins existed ascry30Ca-gap-orf2andcry60Ba-gap-cry60Aa. Thecry30Caand a downstreamorf2gene were oriented in the same direction and separated by 114 bp, andcry60Bawas located 156 bp upstream from and in the same orientation tocry60Aa. The three new protoxin genes were cloned fromB. thuringiensissubsp.jegathesanand expressed in an acrystalliferous strain under the control ofcyt1Agene promoters and the STAB-SD stabilizer sequence. Recombinant strain containing onlycry30Cadid not produce visible inclusion under microscope observation, while that containing bothcry30Caandorf2could produce large inclusions. Cry60Aa and Cry60Ba synthesized either alone or together in the acrystalliferous host could yield large inclusions. In bioassays using the fourth-instar larvae ofCulex quinquefasciatus, Cry60Aa and Cry60Ba alone or together had estimated 50% lethal concentrations of 2.9 to 7.9 μg/ml; however, Cry30Ca with or without ORF2 was not toxic to this mosquito.

A second independent resistance mechanism to Bacillus sphaericus binary toxin targets its alpha-glucosidase receptor in Culex quinquefasciatus

FEBS Journal ◽  
2006 ◽  
Vol 273 (7) ◽  
pp. 1556-1568 ◽  
Author(s):  
Tatiany Patricia Romao ◽  
Karlos Diogo de Melo Chalegre ◽  
Shana Key ◽  
Constancia Flavia Junqueira Ayres ◽  
Claudia Maria Fontes de Oliveira ◽  
...  
Keyword(s):  
Culex Quinquefasciatus ◽  
Resistance Mechanism ◽  
Bacillus Sphaericus ◽  
Binary Toxin ◽  
Alpha Glucosidase
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