Persistence of detectable insecticidal proteins from Bacillus thuringiensis (Cry) and toxicity after adsorption on contrasting soils

Hung, Truong Phuc; Truong, Le Van; Binh, Ngo Dinh; Frutos, Roger; Quiquampoix, Hervé; Staunton, Siobhán

doi:10.1016/j.envpol.2015.09.046

Cited by 23 publications

(23 citation statements)

References 41 publications

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“…Conformational changes may change with time, and this may cause the extraction efficiency to decrease, a phenomenon known as ageing or fixation. No published studies have successfully distinguished between breakdown of Cry protein and fixation as causes of the observed decline in extractable‐detectable protein in soil …”

Section: Introductionmentioning

confidence: 99%

Fate of insecticidalBacillus thuringiensisCry protein in soil: differences between purified toxin and biopesticide formulation

et al. 2016

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For the biopesticide, the observed decline in detectable protein was due to biological factors, possibly including the germination of B. thuringiensis spores, and was favoured by higher temperature. In contrast, for purified proteins, the decline in detectable protein was slower at low temperature, probably because the conformational changes of the soil-adsorbed protein, which cause fixation and hence reduced extraction efficiency, are temperature dependent. © 2016 Society of Chemical Industry.

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Section: Introductionmentioning

confidence: 99%

Fate of insecticidalBacillus thuringiensisCry protein in soil: differences between purified toxin and biopesticide formulation

et al. 2016

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“…Data also showed that almost all of the applied Btk formulation dose was still present on the leaves surface 72 h after spraying 28 , its amount returning close to environmental levels only 28 days after treatment 29 . Finally, Bt spores can survive in the soil and on different supports for months and even years after application [30][31][32][33] . Bt formulations contain also different compounds to protect spores and crystals and aggregate them into a wettable form, surfactants to facilitate spraying and dispersion on plants, and phagostimulants 34,35 .…”

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confidence: 99%

Differential side-effects of Bacillus thuringiensis bioinsecticide on non-target Drosophila flies

Babin

Nawrot-Esposito

Gallet

et al. 2020

Sci Rep

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Bioinsecticides based on Bacillus thuringiensis (Bt) spores and toxins are increasingly popular alternative solutions to control insect pests, with potential impact of their accumulation in the environment on non-target organisms. Here, we tested the effects of chronic exposure to commercial Bt formulations (Bt var. kurstaki and israelensis) on eight non-target Drosophila species present in Bt-treated areas, including D. melanogaster (four strains). Doses up to those recommended for field application (~ 106 Colony Forming Unit (CFU)/g fly medium) did not impact fly development, while no fly emerged at ≥ 1000-fold this dose. Doses between 10- to 100-fold the recommended one increased developmental time and decreased adult emergence rates in a dose-dependent manner, with species-and strain-specific effect amplitudes. Focusing on D. melanogaster, development alterations were due to instar-dependent larval mortality, and the longevity and offspring number of adult flies exposed to bioinsecticide throughout their development were moderately influenced. Our data also suggest a synergy between the formulation compounds (spores, cleaved toxins, additives) might induce the bioinsecticide effects on larval development. Although recommended doses had no impact on non-target Drosophila species, misuse or local environmental accumulation of Bt bioinsecticides could have side-effects on fly populations with potential implications for their associated communities.

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“…Conversely, the few reports on persistent toxicity in the field or under control indicate that these proteins rapidly lose their insecticidal properties due to different causes. Among the environmental factors that negatively affect the persistence of toxicity are temperature, solar radiation, pH, organic matter, and solubilization (Manonmani et al 2008;Hung et al 2016). There are very few studies of the shelf life persistence of Bt endotoxins and commercial formulations.…”

Section: Discussionmentioning

confidence: 99%

“…The loss of Cyt biological activity in stored extracts may be due to the latent presence of proteases, as well as the constant temperature (25°C) for long periods of time. All this can produce conformational changes in its structure (Hung et al 2016), thus hinder toxic activity. However, there are some reports highlighting UV light and sunlight as a primary degradation pathway (Hung et al 2016;Moustafa et al 2018).…”

Section: Discussionmentioning

confidence: 99%

Viability and reconstitution of delta-endotoxins from Bacillus thuringiensis var. israelensis extracts after forty years of storage against Aedes aegypti (Diptera: Culicidae)

Fernández-Chapa

Luna-Olvera

Ramírez-Villalobos

et al. 2021

Egypt J Biol Pest Control

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Background Bacillus thuringiensis subsp. israelensis (Bti) produces insecticidal endotoxins known as Cry and Cyt. Its efficiency and specificity make it the most widely used substance as a biopesticide for controlling disease from vector insects, such as mosquitoes, responsible for important human diseases such as malaria, filariasis, dengue, and yellow fevers. To date, it is proven difficult to develop a commercial product that has more than 2 years of shelf life, and there is little information on the viability of these commercial proteins under prolonged storage conditions. Results This study aimed to evaluate biological activity of reconstituted Bti endotoxins after 40 years of storage against the mosquito Aedes aegypti larvae. Five concentrations of Bti extracts were used for bioassays against 3rd and 4th instars of A. aegypti larvae. All reconstituted endotoxins from stored extracts showed a potency increase. The strain HD-500 from extract 3260 was the most effective insecticide (LC50 = 0.0014 mg/l), followed by 3756 (LC50 = 0.0037 mg/l). These strains were particularly notable, increasing their larvicidal potency one hundredfold and one thousandfold, respectively. Protein profiles in polyacrylamide gels revealed a greater presence of Cyt toxins compared to the stored Bti extracts, which maintained their activity at high concentrations. Conclusion The reconstituted Bti strains presented a great biological activity against A. aegypti larvae, specially extract 3260 (median lethal concentration (LC50) value = 0.0014 mg/l). This considerable larvicidal activity after 40 years under storage was an encouraging signal for the development of future formulation strategies regarding their useful life. The stability of extracts of stored endotoxins produced by Bti decreased significantly, particularly Cyt1A protein, which is responsible for their synergistic activity.

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Persistence of detectable insecticidal proteins from Bacillus thuringiensis (Cry) and toxicity after adsorption on contrasting soils

Cited by 23 publications

References 41 publications

Fate of insecticidalBacillus thuringiensisCry protein in soil: differences between purified toxin and biopesticide formulation

Fate of insecticidalBacillus thuringiensisCry protein in soil: differences between purified toxin and biopesticide formulation

Differential side-effects of Bacillus thuringiensis bioinsecticide on non-target Drosophila flies

Viability and reconstitution of delta-endotoxins from Bacillus thuringiensis var. israelensis extracts after forty years of storage against Aedes aegypti (Diptera: Culicidae)

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