scholarly journals Mtx Toxins Synergize Bacillus sphaericus and Cry11Aa against Susceptible and Insecticide-Resistant Culex quinquefasciatus Larvae

2007 ◽  
Vol 73 (19) ◽  
pp. 6066-6071 ◽  
Author(s):  
Margaret C. Wirth ◽  
Yangkun Yang ◽  
William E. Walton ◽  
Brian A. Federici ◽  
Colin Berry
Keyword(s):  
Escherichia Coli ◽  
Bacillus Thuringiensis ◽  
Insecticide Resistance ◽  
Culex Quinquefasciatus ◽  
Vegetative Growth ◽  
Bacillus Sphaericus ◽  
Highly Active ◽  
Level Of Activity ◽  
Low Concentrations ◽  
High Level

ABSTRACT Two mosquitocidal toxins (Mtx) of Bacillus sphaericus, which are produced during vegetative growth, were investigated for their potential to increase toxicity and reduce the expression of insecticide resistance through their interactions with other mosquitocidal proteins. Mtx-1 and Mtx-2 were fused with glutathione S-transferase and produced in Escherichia coli, after which lyophilized powders of these fusions were assayed against Culex quinquefasciatus larvae. Both Mtx proteins showed a high level of activity against susceptible C. quinquefasciatus mosquitoes, with 50% lethal concentrations (LC50) of Mtx-1 and Mtx-2 of 0.246 and 4.13 μg/ml, respectively. The LC50s were 0.406 to 0.430 μg/ml when Mtx-1 or Mtx-2 was mixed with B. sphaericus, and synergy improved activity and reduced resistance levels. When the proteins were combined with a recombinant Bacillus thuringiensis strain that produces Cry11Aa, the mixtures were highly active against Cry11A-resistant larvae and resistance was also reduced. The mixture of two Mtx toxins and B. sphaericus was 10 times more active against susceptible mosquitoes than B. sphaericus alone, demonstrating the influence of relatively low concentrations of these toxins. These results show that, similar to Cyt toxins from B. thuringiensis subsp. israelensis, Mtx toxins can increase the toxicity of other mosquitocidal proteins and may be useful for both increasing the activity of commercial bacterial larvicides and managing potential resistance to these substances among mosquito populations.

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 Cyt1Ab1 and Cyt2Ba1 from Bacillus thuringiensis subsp. medellin and B. thuringiensis subsp. israelensis Synergize Bacillus sphaericus against Aedes aegypti and Resistant Culex quinquefasciatus (Diptera: Culicidae)

2001 ◽  
Vol 67 (7) ◽  
pp. 3280-3284 ◽  
Author(s):  
Margaret C. Wirth ◽  
Armelle Del�cluse ◽  
William E. Walton
Keyword(s):  
Bacillus Thuringiensis ◽  
Aedes Aegypti ◽  
Insecticide Resistance ◽  
Culex Quinquefasciatus ◽  
Bacillus Sphaericus ◽  
Bacillus Thuringiensis Subsp

ABSTRACT The interaction of two cytolytic toxins, Cyt1Ab fromBacillus thuringiensis subsp. medellinand Cyt2Ba from Bacillus thuringiensis subsp.israelensis, with Bacillus sphaericus was evaluated against susceptible and resistant Culex quinquefasciatus and the nonsensitive species Aedes aegypti. Mixtures of B. sphaericus with either cytolytic toxin were synergistic, and B. sphaericusresistance in C. quinquefasciatus was suppressed from >17,000- to 2-fold with a 3:1 mixture of B. sphaericusand Cyt1Ab. This trait may prove useful for combating insecticide resistance and for improving the activity of microbial insecticides.

scholarly journals THE USE OF AGENTS BASED ON THE BACTERIUM BACILLUS THURINGIENSIS VAR. ISRAELENSIS FOR MOSQUITO CONTROL

2019 ◽  
Vol 98 (8) ◽  
pp. 893-896
Author(s):  
Svetlana A. Roslavtseva
Keyword(s):  
Bacillus Thuringiensis ◽  
Aedes Aegypti ◽  
Synergistic Effect ◽  
Mosquito Control ◽  
Mosquito Species ◽  
Bacillus Sphaericus ◽  
Development Of Resistance ◽  
Blood Sucking ◽  
Low Concentrations ◽  
Bacterium Bacillus

Mosquito control is necessary to improve the epidemic and, consequently, the sanitary and hygienic situation in human settlements. At the same time, the safest and more environmentally friendly way of controlling is not the fight against adult mosquitoes, but the treatment of reservoirs with microbiological larvicides based on entomopathogenic, aerobic, spore-forming, saprophytic bacteria Bacillus thuringiensis (de Barjac) (Bti). A new serotype of the bacterium B. thuringiensis was found in Israel in the Negev desert. This serotype being more active against larvae of blood-sucking and non-blood-sucking mosquitoes and midges than previously known serotypes, was named israelensis. Bti endotoxin is a typical insecticide with intestinal type of action for different mosquito species. For example, Bti H14 is highly insecticidal to the larvae of Aedes aegypti and Ae. albopictus at very low concentrations. The parasporal body (endotoxin crystal), a crystalline protein consisted of four main polypeptides and two minor polypeptides, possesses of a larvicidal action. Larvicidal activity is associated with a synergistic effect in a combination of four polypeptides. The possibility of development of resistance to products based on Bti and Bacillus sphaericus in populations of mosquitoes (Culicidae) was investigated. The use of domestic microbiological formulations based on Bti («Baktitsid», «Larviol-pasta», and «Antinat») was shown an eradication the larvae of bloodsucking mosquitoes and midges to be possible and rational, since they are not generated resistant populations of mosquitoes. This is confirmed by more than 30 years of the use of such formulations.

Interaction of the Bacillus sphaericus mosquito larvicidal proteins

1990 ◽  
Vol 36 (12) ◽  
pp. 870-878 ◽  
Author(s):  
Elizabeth W. Davidson ◽  
Coreen Oei ◽  
Marian Meyer ◽  
Allan L. Bieber ◽  
John Hindley ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Sequence Analysis ◽  
Key Words ◽  
Culex Quinquefasciatus ◽  
Bacillus Sphaericus ◽  
Insecticidal Proteins ◽  
Posterior Midgut ◽  
Sds Page ◽  
Reduced Activity

Genes for 51.4- and 41.9-kDa insecticidal proteins of Bacillus sphaericus were separately cloned and expressed in Escherichia coli. Both proteins were required for toxicity. Approximately equal numbers of cells containing the 51.4- and 41.9-kDa proteins produced the greatest toxicity; excess 41.9-kDa protein did not affect toxicity, whereas excess 51.4-kDa protein reduced activity. Larvae were killed when 41.9-kDa protein was fed up to 24 h after the 51.4-kDa protein, but not when the order of feeding was reversed. Radiolabelled toxins bound in approximately equal amounts to the gastric caecum and posterior midgut of Culex quinquefasciatus larvae. Radiolabelled 51.4-kDa protein was rapidly degraded by ca. 12–13 kDa in the larval gut, while 41.9-kDa protein was degraded by 1–2 kDa. Nonreduced toxin extracted from B. sphaericus produced a band on SDS–PAGE of ca. 68–74 kDa that contained both 51.4- and 41.9-kDa proteins based on sequence analysis, and a band of ca. 51 kDa that contained primarily 41.9-kDa protein. Escherichia coli containing 51.4-kDa protein enhanced toxicity of the latter eluted SDS-PAGE band. These proteins may associate very strongly, and trace amounts of 51.4-kDa protein in preparations of 41.9-kDa protein from B. sphaericus may be responsible for the previously reported toxicity of the latter. Key words: Bacillus sphaericus, toxin, mosquito, cloning.

scholarly journals Eficiência e Persistência de Três Produtos Comerciais à Base de Bacillus thuringiensis israelensis e Bacillus sphaericus no controle de Culicidae (Diptera) em Lagoas de Tratamento de Efluentes

2010 ◽  
Vol 3 (3) ◽  
pp. 85-88
Author(s):  
Jose Lopes ◽  
Fernando Pereira dos Santos ◽  
João Antonio Cyrino Zequi ◽  
Denise Miguel Petroni
Keyword(s):  
Bacillus Thuringiensis ◽  
Culex Quinquefasciatus ◽  
Bacillus Sphaericus ◽  
Pathogen Transmission ◽  
Effluent Treatment ◽  
Alternative Methods ◽  
Liquid Formulation ◽  
Bacillus Thuringiensis Israelensis ◽  
Commercial Products ◽  
Culex Nigripalpus

Resumo. A ação hematofágica exercida por fêmeas de algumas espécies de Culicidae sobre o homem e outros animais pode estar diretamente relacionada à transmissão de patógenos, além de provocar reações alérgicas e causar incômodo. O aparecimento de populações resistentes aos inseticidas químicos impulsiona o uso de métodos de controle alternativos, principalmente o biológico. Objetivando testar a eficiência e persistência de produtos comerciais com principio ativo a base de Bacillus thuringiensis israelensis Berliner e Bacillus sphaericus Neide foram realizados experimentos em três lagoas de tratamento de efluentes, sobre larvas de Culicidae. Testou-se Vectolex (formulação granulada de B. sphaericus), Sphaericus (Formulação líquida de B. sphaericus) e Bt-horus (formulação líquida de B. thuringiensis). As aplicações foram realizadas quinzenalmente com avaliações realizadas a 0, 24, 48, 72 e 120 horas após a aplicação. As lagoas estavam colonizadas por Culex nigripalpus Theobald (1,5%), Culex saltanensis Dyar (2,25%) e Culex quinquefasciatus Say (96,25%). Com o produto Bt horus, registrou-se redução larval de 89,06%, 83,97% e 89,96% respectivamente a 24, 48 e 72 horas após a aplicação. Nos produtos contendo B. sphaericus, respectivamente na formulação granulada e líquida observou-se uma redução de 98,89 % e 98,34%, após 24 horas da aplicação e de 99,79% e 99,78% após 48 horas. Os produtos e as diferentes formulações foram eficientes no controle de larvas das três espécies de culicídeos em lagoas com grande quantidade de matéria orgânica, porém a persistência verificada foi de dois e três dias para produtos contendo respectivamente B. sphaericus e B. thuringiensis israelensis. Efficiency and Persistence of Three Commercial Products Based on Bacillus thuringiensis israelensis and Bacillus sphaericus in Controlling Culicidae (Diptera) in Effluent Treatment Lagoons Abstract. The hematofagic effect caused by females belonging to some species of Culicidae on humans and animals can be directly related to pathogen transmission, allergic reactions and uneasiness. The emergence of populations resistant to chemical insecticides has fostered the use of alternative methods, mainly biological control. The trials were conducted in three effluent treatment lagoons, on larvae of Culicidae to test the efficiency and persistence of commercial products whose active principles are based on Bacillus thuringiensis israelensis Berliner and Bacillus sphaericus Neide. The products tested were Vectolex (a granulated formulation of B. sphaericus), Sphaericus (a liquid formulation of B. sphaericus) and Bt-horus (a liquid formulation of B. thuringiensis). The products were applied biweekly and evaluations were conducted 0, 24, 48, 72, and 120 hours after each application. The lagoons were colonized by Culex nigripalpus Theobald (1.5%), Culex saltanensis Dyar (2.25%), and Culex quinquefasciatus Say (96.25%). Bt-horus reduced larvae by 89.06%, 83.97% and 89.96% at 24, 48 and 72 hours after product application, respectively. The granulated and the liquid formulations containing B. sphaericus reduced larvae by 98.89 % and 98.34% 24 hours after application, and by 99.79% and 99.78% after 48 hours, respectively. The products and the different formulations were effective in controlling larvae of all three Culicidae species in lagoons with high levels of organic matter, but the persistence was recorded in two and three days for products containing respectively B. sphaericus and B. thuringiensis israelensis.

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.

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