scholarly journals Toxicity of Bacillus thuringiensis subsp. israelensis to adult Aedes aegypti mosquitoes.

1983 ◽  
Vol 46 (2) ◽  
pp. 312-315 ◽  
Author(s):  
M J Klowden ◽  
G A Held ◽  
L A Bulla
Keyword(s):  
Bacillus Thuringiensis ◽  
Aedes Aegypti ◽  
Bacillus Thuringiensis Subsp

scholarly journals Cloning and Expression of Two Crystal Protein Genes, cry30Ba1 and cry44Aa1, Obtained from a Highly Mosquitocidal Strain, Bacillus thuringiensis subsp. entomocidus INA288

2006 ◽  
Vol 72 (8) ◽  
pp. 5673-5676 ◽  
Author(s):  
Takeshi Ito ◽  
Tomonori Ikeya ◽  
Ken Sahara ◽  
Hisanori Bando ◽  
Shin-ichiro Asano
Keyword(s):  
Bacillus Thuringiensis ◽  
Aedes Aegypti ◽  
Culex Pipiens ◽  
Crystal Protein ◽  
Cloning And Expression ◽  
Culex Pipiens Pallens ◽  
Bacillus Thuringiensis Subsp ◽  
Pipiens Pallens ◽  
Crystal Protein Genes

ABSTRACT Two novel crystal protein genes, cry30Ba and cry44Aa, were cloned from Bacillus thuringiensis subsp. entomocidus INA288 and expressed in an acrystalliferous strain. Cry44Aa crystals were highly toxic to second-instar Culex pipiens pallens (50% mortality concentration [LC50] = 6 ng/ml) and Aedes aegypti (LC50 = 12 ng/ml); however, Cry30Ba crystals were not toxic.

scholarly journals Effects of two formulations based on Bacillus thuringiensis subsp. israelensis on Aedes aegypti mosquito larvae under laboratory conditions

2008 ◽  
Vol 23 (4) ◽  
pp. 251-258
Author(s):  
Milenka Peric ◽  
Mirjana Prijovic ◽  
Goran Andric
Keyword(s):  
Bacillus Thuringiensis ◽  
Aedes Aegypti ◽  
Aqueous Suspension ◽  
Pure Water ◽  
Clay Content ◽  
Experimental Period ◽  
Mosquito Larvae ◽  
Water Dispersible ◽  
Bacillus Thuringiensis Subsp ◽  
Zero Time

Toxicity and persistence of two formulations based on Bacillus thuringiensis subsp. israelensis applied to Aedes aegypti mosquito larvae were tested under laborabory conditions. The formulations were: a) water dispersible granules (product VectoBac WDG), and b) aqueous suspension (product VectoBac 12AS). The effects of both products on mosquito larvae were tested immediately after their dilution in pure water (zero time) and in 1-, 2-, 8- and 13-day old solutions. The two products were also tested in mixtures of water and clay at a rate of 0.5 g clay/150 ml water immediately after product dilution, and in one-day old solutions containing 0.1 and 0.05 g of clay in the same amount of water. The product VectoBac WDG was persistent and highly effective against Ae. aegypti larvae in pure water after the longest experimental period of 13 days, and significantly more effective than VectoBac 12AS at equal rates of application. The effectiveness of VectoBac 12AS weakened significantly after 8 and 13 days of treatment, compared to the effects at zero time and in 1- and 2-day old solutions. High clay content in water significantly reduced the larvicidal effectiveness of both products, indicating its possible compromising role during product application in practice.

scholarly journals Cadherin binding is not a limiting step for Bacillus thuringiensis subsp. israelensis Cry4Ba toxicity to Aedes aegypti larvae

2012 ◽  
Vol 443 (3) ◽  
pp. 711-717 ◽  
Author(s):  
Claudia Rodríguez-Almazán ◽  
Esmeralda Z. Reyes ◽  
Fernando Zúñiga-Navarrete ◽  
Carlos Muñoz-Garay ◽  
Isabel Gómez ◽  
...  
Keyword(s):  
Bacillus Thuringiensis ◽  
Aedes Aegypti ◽  
Lipid Bilayers ◽  
Insect Pests ◽  
Cry Toxins ◽  
Bacillus Thuringiensis Subsp ◽  
Limiting Step ◽  
Cry Toxin ◽  
Receptor Fragment

Bacillus thuringiensis subsp. israelensis produces three Cry toxins (Cry4Aa, Cry4Ba and Cry11Aa) that are active against Aedes aegypti larvae. The identification of the rate-limiting binding steps of Cry toxins that are used for insect control in the field, such as those of B. thuringiensis subsp. israelensis, should provide targets for improving insecticides against important insect pests. Previous studies showed that Cry11Aa binds to cadherin receptor fragment CR7–11 (cadherin repeats 7–11) with high affinity. Binding to cadherin has been proposed to facilitate Cry toxin oligomer formation. In the present study, we show that Cry4Ba binds to CR7–11 with 9-fold lower binding affinity compared with Cry11Aa. Oligomerization assays showed that Cry4Ba is capable of forming oligomers when proteolytically activated in vitro in the absence of the CR7–11 fragment in contrast with Cry11Aa that formed oligomers only in the presence of CR7–11. Pore-formation assays in planar lipid bilayers showed that Cry4Ba oligomers were proficient in opening ion channels. Finally, silencing the cadherin gene by dsRNA (double-stranded RNA) showed that silenced larvae were more tolerant to Cry11Aa in contrast with Cry4Ba, which showed similar toxic levels to those of control larvae. These findings show that cadherin binding is not a limiting step for Cry4Ba toxicity to A. aegypti larvae.

scholarly journals Bacillus thuringiensis subsp. israelensis producing endochitinase ChiA74Δsp inclusions and its improved activity against Aedes aegypti

2015 ◽  
Vol 119 (6) ◽  
pp. 1692-1699 ◽  
Author(s):  
E.O. Juárez-Hernández ◽  
L.E. Casados-Vázquez ◽  
M.C. del Rincón-Castro ◽  
R. Salcedo-Hernández ◽  
D.K. Bideshi ◽  
...  
Keyword(s):  
Bacillus Thuringiensis ◽  
Aedes Aegypti ◽  
Bacillus Thuringiensis Subsp

scholarly journals Toxicity of Cry2 proteins from Bacillus thuringiensis subsp. thuringiensis strain T01-328 against Aedes aegypti (Diptera: Culicidae)

2018 ◽  
Vol 85 (0) ◽  
Author(s):  
Marina Cabral Ricoldi ◽  
Camila Soares Figueiredo ◽  
Janete Apparecida Desidério
Keyword(s):  
Bacillus Thuringiensis ◽  
Aedes Aegypti ◽  
Public Health Problem ◽  
Mosquito Larvae ◽  
Major Public Health Problem ◽  
Virus Diseases ◽  
Expression In Escherichia Coli ◽  
Bacillus Thuringiensis Subsp ◽  
Zika Fever ◽  
Thuringiensis Strain

ABSTRACT: Bacillus thuringiensis subsp. israelensis has been used to control the Aedes aegypti (Diptera: Culicidae) mosquito larvae, the vector of virus diseases such as dengue, Chikungunya and Zika fever, which have become a major public health problem in Brazil and other tropical countries since the climate favors the proliferation and development of the transmitting vector. Because B. thuringiensis has shown potential for controlling insects of the Diptera order, this work aimed at testing the Bacillus thuringiensis subsp. thuringiensis strain T01-328 and its proteins Cry2Aa and Cry2Ab for control A. aegypti and at comparing the results to the B. thuringiensis subsp. israelensis specific dipteran strain. To this end, bioassays using spore-crystal of both strains, and Cry2Aa and Cry2Ab proteins from the heterologous expression in Escherichia coli, were performed against A. aegypti larvae. The results showed that the B. thuringiensis thuringiensis T01-328 has insecticidal activity against the larvae, but it is less toxic than B. thuringiensis subsp. israelensis. Cry2Aa and Cry2Ab proteins expressed heterologously were effective for controlling A. aegypti larvae. Therefore, the results indicate that the Cry2Aa and Cry2Ab proteins of the B. thuringiensis thuringiensis T01-328 can be used as an alternative to assist in the control of A. aegypti.

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