Isolation and molecular characterization of Bacillus thuringiensis found in soils of the Cerrado region of Brazil, and their toxicity to Aedes aegypti larvae

Lobo, Katiane dos Santos; Silva, Joelma Soares da; Silva, Maria Cleoneide da; Tadei, Wanderli Pedro; Polanczyk, Ricardo Antônio; Pinheiro, Valéria Cristina Soares

doi:10.1016/j.rbe.2017.11.004

Cited by 26 publications

(30 citation statements)

References 55 publications

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“…These results were similar to those observed for Bti T14001 and BtMA-750, which contain seven and five genes that are toxic to mosquito larvae, respectively (Rey et al, 1998;Cavados et al, 2004;Soares-da-Silva et al, 2017). BtMA-401, despite harbouring only one gene, did not present the standard genes found in mosquito-acting strains when analysed for its protein content by the sodium dodecyl sulphate-polyacrylamide-based discontinuous gel (SDS-PAGE) method, showing a profile similar to that of Bti, which was verified by Lobo et al (2018). There are a large number of proteins within the Cry and Cyt families, many of which have similar sizes, which may explain the similar protein profiles among Bt isolates.…”

Section: Discussionsupporting

confidence: 74%

“…A total of nine Bt isolates that showed high toxicity to A. aegypti larvae, as previously determined in susceptibility bioassays (Lobo et al, 2018), were selected. The gene profiles of these isolates differed from those of the strains that are already used to control mosquitoes, such as B. thuringiensis subsp.…”

Section: Selection Of Bacillus Thuringiensis Isolatesmentioning

confidence: 99%

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Isolates of Bacillus thuringiensis from Maranhão biomes with potential insecticidal action against Aedes aegypti larvae (Diptera, Culicidae)

et al. 2021

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Entomopathogenic agents are viable and effective options due to their selective action against insects but benign effects on humans and the environment. The most promising entomopathogens include subspecies of Bacillus thuringiensis (Bt), which are widely used for the biological control of insects, including mosquito vectors of human pathogens. The efficacy of B. thuringiensis toxicity has led to the search for new potentially toxic isolates in different regions of the world. Therefore, soil samples from the Amazon, Cerrado and Caatinga biomes of the state of Maranhão were evaluated for their potential larvicidal action against Aedes aegypti. The isolates with high toxicity to mosquito larvae, as detected by bioassays, were subjected to histological evaluation under a light microscope to identify the genes potentially responsible for the toxicity. Additionally, the toxic effects of these isolates on the intestinal epithelium were assessed. In the new B. thuringiensis isolates toxic to A. aegypti larvae, cry and cyt genes were amplified at different frequencies, with cry4, cyt1, cry32, cry10 and cry11 being the most frequent (33-55%) among those investigated. These genes encode specific proteins toxic to dipterans and may explain the severe morphological changes in the intestine of A. aegypti larvae caused by the toxins of the isolates.

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Section: Discussionsupporting

confidence: 74%

Section: Selection Of Bacillus Thuringiensis Isolatesmentioning

confidence: 99%

Isolates of Bacillus thuringiensis from Maranhão biomes with potential insecticidal action against Aedes aegypti larvae (Diptera, Culicidae)

et al. 2021

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“…However soil samples have shown greater richness in the diversity of Bacillus species and related genera compared to other sources making it the most preferred substrate for isolation (González et al, 2013;Lobo et al, 2017;Suryadi et al, 2016). In this study, 453 Bacillus strains and related genera were isolated from 100 soil samples collected from random Strain PCR results 16s rRNA binA binB mtx1 mtx2 mtx3 cry48A cry49A cry4A cry11A cyt1A Ls C3-41 Positive; -, Negative. sites in Kenya.…”

Section: Discussionmentioning

confidence: 95%

“…Notably, only one mosquito species (C. quinquefasciatus) was applied for mosquitocidal analysis in this study and this could have contributed to the low percentage of toxic isolates due to the smaller number of described toxins known to affect this group of insects (Lobo et al, 2017). Phenotypic characterization of the toxic isolates marked the basic identification procedure where six of the isolates showed high similarity to the reference strain L.s C3-41 while one isolate showed high similarity to the reference strain B. thuringiensis var.…”

Section: Discussionmentioning

confidence: 99%

Isolation, identification and evaluation of mosquito entomopathogenic Bacillus species and related genera from randomly selected sites in Kenya

Karungu¹,

Huang²,

Atoni³

et al. 2018

Afr. J. Microbiol. Res.

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This study was carried out to identify specific mosquitocidal Bacillus species and related genera for future development of biopesticides in local mosquito control program in Kenya. Bacterial isolation was conducted from 100 soil samples through pasteurization method and preliminary identification conducted through phenotypical analysis. Toxicity analysis was performed through bioassays and lethal concentrations (LC) were determined using probit analysis. Toxic isolates were further identified through analysis of the 16s rRNA and screening of toxin genes through PCR. Expression of toxin proteins was performed using SDS-PAGE. Out of 453 isolates, 7 of them were found to yield highly potent toxicity (>50% mortality) against Culex quinquefasciatus during the initial toxicity assays. Among them, two isolates KDHa3 and SKDHb5, with LC50 values of 0.007mg/L and 0.008mg/L, respectively, were the most toxic against the target. Phylogenetic analysis based on 16s rRNA showed high homology to Lysinibacillus sphaericus (six isolates) and Bacillus thuringiensis (one isolate). Various toxin genes encoding BinA, BinB, Mtx (1, 2 and 3), Cry48A, Cry49A, Cry4A, Cry11A and Cyt1A were detected among the isolates. The protein profiles using SDS-PAGE were consistent with the standard strains Lysinibacillus sphaericus C3-41 and B. thuringiensis var. israelensis. Native toxic Bacillus species and related genera were identified with this study being the first to report highly toxic strains of L. sphaericus and B. thuringiensis strains from Kenyan soil samples.

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“…In this context, the conservation of natural enemies that act as larvae predators and the entomopathogenic bacteria -Bacillus thuringiensis var. Israelis (Bti) and Lysinibacillus sphaericus -can potentially combat the immature forms of vector mosquitoes (Lobo et al 2018, Rodrigues et al 2013, Soaresda-Silva et al 2015.…”

Section: Introductionmentioning

confidence: 99%

Effects of diflubenzuron on associated insect fauna with Anopheles(Diptera: Culicidae) in laboratory, partial-field, and field conditions in the Central Amazon

Ferreira

Arcos

Maia

et al. 2020

An. Acad. Bras. Ciênc.

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This study aimed to analyze the possible effects of diflubenzuron on the associated insect fauna under laboratory, semi-field and field conditions. Laboratory bioassays were performed in aquariums with mortality readings (%) every 24h until 96h, and in semi-fields, insects were kept in basins with readings every 24h for up to 12 days, in triplicates and a control. In the field experiment, a collection was performed before the application of diflubenzuron in ten brick factory pits (25m²) and 15 post-application. The values of LC 50 and LC 90 for Chironomus were 2.77x10-3g/L and 0.86g/L, respectively, and for Buenoa, they were 0.019g/L and 0.92g/L, a strong relationship was observed between mortality and exposure time (r²>0.8) in all concentrations used. In semi-field, similar mean values of emergency inhibition were observed, except for Euthyplociidae, which was more sensitive. There was no significant difference between the data of richness and diversity of aquatic insects in the field experiment, considering an interval of 15 days (p=0.32). Finally, the data suggest that diflubenzuron may have a negative effect on the associated insect fauna, but in the field experiment the environmental conditions of Anopheles breeding sites may have affected its efficiency.

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Isolation and molecular characterization of Bacillus thuringiensis found in soils of the Cerrado region of Brazil, and their toxicity to Aedes aegypti larvae

Cited by 26 publications

References 55 publications

Isolates of Bacillus thuringiensis from Maranhão biomes with potential insecticidal action against Aedes aegypti larvae (Diptera, Culicidae)

Isolates of Bacillus thuringiensis from Maranhão biomes with potential insecticidal action against Aedes aegypti larvae (Diptera, Culicidae)

Isolation, identification and evaluation of mosquito entomopathogenic Bacillus species and related genera from randomly selected sites in Kenya

Effects of diflubenzuron on associated insect fauna with Anopheles(Diptera: Culicidae) in laboratory, partial-field, and field conditions in the Central Amazon

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