| toxins for transgenic resistance to hemipteran pests. | the sap sucking insects (hemiptera), which include aphids, whiteflies, plant bugs and stink bugs, have emerged as major agricultural pests. the hemiptera cause direct damage by feeding on crops, and in some cases indirect damage by transmission of plant viruses. current management relies almost exclusively on application of classical chemical insecticides. while the development of transgenic crops expressing toxins derived from the bacterium bacillus thuringiensis (bt) has provided effective pla ... | 2012 | 22822455 |
| the endochitinase chia btt of bacillus thuringiensis subsp. tenebrionis dsm-2803 and its potential use to control the phytopathogen colletotrichum gloeosporioides. | bacillus thuringiensis subsp. tenebrionis dsm-2803 has been studied extensively and spore/crystal mixtures of this strain are used widely in commercial products to control coleopteran pests. the endochitinase chia btt gene of b. thuringiensis subsp. tenebrionis dsm-2803 was cloned and expressed in escherichia coli. the recombinant 6x-histidine tagged protein (rchia btt, ~74 kda), was purified by a hitrap ni affinity column. the km of rchia btt was 0.847 μmol l(-1) and its optimal activity occurr ... | 2016 | 27173732 |
| expanding the use of a fluorogenic method to determine activity and mode of action of bacillus thuringiensis bacteriocins against gram-positive and gram-negative bacteria. | previously we described a rapid fluorogenic method to measure the activity of five bacteriocins produced by mexican strains of bacillus thuringiensis against b. cereus 183. here we standardize this method to efficiently determine the activity of bacteriocins against both gram-positive and gram-negative bacteria. it was determined that the crucial parameter required to obtain reproducible results was the number of cells used in the assay, that is, ~4 × 10(8) cell/ml and ~7 × 10(8) cell/ml, respec ... | 2012 | 22919330 |
| islands of non-essential genes, including a dna translocation operon, in the genome of bacteriophage 0305ϕ8-36. | we investigate genes of lytic, bacillus thuringiensis bacteriophage 0305ϕ8-36 that are non-essential for laboratory propagation, but might have a function in the wild. we isolate deletion mutants to identify these genes. the non-permutation of the genome (218.948 kb, with a 6.479 kb terminal repeat and 247 identified orfs) simplifies isolation of deletion mutants. we find two islands of non-essential genes. the first island (3.01% of the genomic dna) has an informatically identified dna transloc ... | 2012 | 22666654 |
| does changing the predicted dynamics of a phospholipase c alter activity and membrane binding? | the enzymatic activity of secreted phosphatidylinositol-specific phospholipase c (pi-plc) enzymes is associated with bacterial virulence. although the pi-plc active site has no obvious lid, molecular-dynamics simulations suggest that correlated loop motions may limit access to the active site, and two pro residues, pro(245) and pro(254), are associated with these correlated motions. whereas the region containing both pro residues is quite variable among pi-plcs, it shows high conservation in vir ... | 2013 | 23332071 |
| new role for dcr-1/dicer in caenorhabditis elegans innate immunity against the highly virulent bacterium bacillus thuringiensis db27. | bacillus thuringiensis produces toxins that target invertebrates, including caenorhabditis elegans. virulence of bacillus strains is often highly specific, such that b. thuringiensis strain db27 is highly pathogenic to c. elegans but shows no virulence for another model nematode, pristionchus pacificus. to uncover the underlying mechanisms of the differential responses of the two nematodes to b. thuringiensis db27 and to reveal the c. elegans defense mechanisms against this pathogen, we conducte ... | 2013 | 23918784 |
| infection routes matter in population-specific responses of the red flour beetle to the entomopathogen bacillus thuringiensis. | pathogens can infect their hosts through different routes. for studying the consequences for host resistance, we here used the entomopathogen bacillus thuringiensis and the red flour beetle tribolium castaneum for oral and systemic (i. e. pricking the cuticle) experimental infection. in order to characterize the molecular mechanisms underpinning the two different infection routes, the transcriptomes of beetles of two different t. castaneum populations--one recently collected population (cro1) an ... | 2014 | 24908078 |
| identification of abcc2 as a binding protein of cry1ac on brush border membrane vesicles from helicoverpa armigera by an improved pull-down assay. | cry1ac toxin-binding proteins from helicoverpa armigera brush border membrane vesicles were identified by an improved pull-down method that involves coupling cry1ac to cnbr agarose combined with liquid chromatography-tandem mass spectrometry (lc-ms/ms). according to the lc-ms/ms results, cry1ac toxin could bind to six classes of aminopeptidase-n, alkaline phosphatase, cadherin-like protein, atp-binding cassette transporter subfamily c protein (abcc2), actin, atpase, polycalin, and some other pro ... | 2016 | 27037552 |
| bacillus thuringiensis crystal protein cry6aa triggers caenorhabditis elegans necrosis pathway mediated by aspartic protease (asp-1). | cell death plays an important role in host-pathogen interactions. crystal proteins (toxins) are essential components of bacillus thuringiensis (bt) biological pesticides because of their specific toxicity against insects and nematodes. however, the mode of action by which crystal toxins to induce cell death is not completely understood. here we show that crystal toxin triggers cell death by necrosis signaling pathway using crystal toxin cry6aa-caenorhabditis elegans toxin-host interaction system ... | 2016 | 26795495 |
| transstadial effects of bti on traits of aedes aegypti and infection with dengue virus. | most mosquito control efforts are primarily focused on reducing the adult population size mediated by reductions in the larval population, which should lower risk of disease transmission. although the aim of larviciding is to reduce larval abundance and thus recruitment of adults, nonlethal effects on adults are possible, including transstadial effects on phenotypes of adults such as survival and pathogen infection and transmission. in addition, the mortality induced by control efforts may act i ... | 2016 | 26871951 |
| antibiotics influence the toxicity of the delta endotoxins of bacillus thuringiensis towards the cotton bollworm, helicoverpa armigera. | the cotton bollworm, helicoverpa armigera is one of the most important crop pests worldwide. it has developed high levels of resistance to synthetic insecticides, and hence, bacillus thuringiensis (bt) formulations are used as a safer pesticide and the bt genes have been deployed in transgenic crops for controlling this pest. there is an apprehension that h. armigera might develop resistance to transgenic crops in future. therefore, we studied the role of gut microbes by eliminating them with an ... | 2014 | 25059716 |
| mosquitocidal properties of bacillus species isolated from mangroves of vellar estuary, southeast coast of india. | samples collected from the mangroves of vellar estuary yielded a mosquitocidal bacterium, whose secondary metabolites exhibited mosquito larvicidal and pupicidal activity. the bacterium was isolated using standard microbiological methods and identified using classical biochemical tests. the mosquitocidal bacterium was identified as bacillus subtilis, bacillus thuringiensis, bacillus sphaericus and bacillus cereus. mosquitocidal metabolite(s) was separated from the culture supernatant of the bact ... | 2013 | 26345039 |
| salinity-tolerant larvae of mosquito vectors in the tropical coast of jaffna, sri lanka and the effect of salinity on the toxicity of bacillus thuringiensis to aedes aegypti larvae. | dengue, chikungunya, malaria, filariasis and japanese encephalitis are common mosquito-borne diseases endemic to sri lanka. aedes aegypti and aedes albopictus, the major vectors of dengue, were recently shown to undergo pre-imaginal development in brackish water bodies in the island. a limited survey of selected coastal localities of the jaffna district in northern sri lanka was carried out to identify mosquito species undergoing pre-imaginal development in brackish and saline waters. the effect ... | 2012 | 23174003 |
| isolation and characterization of native bacillus thuringiensis strains from saudi arabia with enhanced larvicidal toxicity against the mosquito vector anopheles gambiae (s.l.). | worldwide, mosquito vectors are transmitting several etiological agents of important human diseases, including malaria, causing millions of deaths every year. in saudi arabia, as elsewhere, vector-control is based mostly on chemical insecticides which may be toxic and cause environmental deprivation. here, to support the development of bio-pesticide alternatives, a study was conducted to identify native bacillus thuringiensis (bt) isolates with improved toxicity against the malaria vector, anoph ... | 2016 | 27993165 |
| combining attractants and larvicides in biodegradable matrices for sustainable mosquito vector control. | there is a global need for cost-effective and environmentally friendly tools for control of mosquitoes and mosquito-borne diseases. one potential way to achieve this is to combine already available tools to gain synergistic effects to reduce vector mosquito populations. another possible way to improve mosquito control is to extend the active period of a given control agent, enabling less frequent applications and consequently, more efficient and longer lasting vector population suppression. | 2016 | 27768698 |
| spinosad: a biorational mosquito larvicide for use in car tires in southern mexico. | car tires are important habitats for mosquito development because of the high density populations they can harbor and their presence in urban settings. water in experimental tires was treated with one of three insecticides or an untreated control. aquatic invertebrates were sampled at weekly intervals. eggs, larval and pupal samples were laboratory-reared to estimate seasonal fluctuations in aedes aegypti and ae. albopictus abundance. | 2012 | 22608138 |
| invasive process and repeated cross-sectional surveys of the mosquito aedes japonicus japonicus establishment in belgium. | when accidentally introduced in a new location, a species does not necessarily readily become invasive, but it usually needs several years to adapt to its new environment. in 2009, a national mosquito survey (modirisk) reported the introduction and possible establishment of an invasive mosquito species, aedes j. japonicus, in belgium. first collected in 2002 in the village of natoye from a second-hand tire company, then sampled in 2003 and 2004, the presence of adults and larvae was confirmed in ... | 2014 | 24694576 |
| susceptibility profile and metabolic mechanisms involved in aedes aegypti and aedes albopictus resistant to ddt and deltamethrin in the central african republic. | aedes aegypti and ae. albopictus are the main epidemic vectors of dengue, chikungunya and zika viruses worldwide. their control during epidemics relies mainly on control of larvae and adults with insecticides. unfortunately, loss of susceptibility of both species to several insecticide classes limits the efficacy of interventions. in africa, where aedes-borne viruses are of growing concern, few data are available on resistance to insecticides. to fill this gap, we assessed the susceptibility to ... | 2016 | 27881148 |
| the persistence and ecological impacts of a cyanobacterium genetically engineered to express mosquitocidal bacillus thuringiensis toxins. | the cyanobacterium anabaena pcc 7120#11 has been genetically engineered to act as a delivery vehicle for bacillus thuringiensis subspecies israelensis mosquitocidal toxins. to address ecological concerns about releasing this genetically engineered microorganism into the environment for mosquito larva control, the persistence and ecological impacts of pcc 7120#11 was evaluated using multi-species, standardized aquatic microcosms. | 2016 | 27165108 |
| bacterial larvicide, bacillus thuringiensis israelensis strain am 65-52 water dispersible granule formulation impacts both dengue vector, aedes aegypti (l.) population density and disease transmission in cambodia. | a multi-phased study was conducted in cambodia from 2005-2011 to measure the impact of larviciding with the bacterial larvicide, bacillus thuringiensis israelensis (bti), a water dispersible granule (wg) formulation on the vector, aedes aegypti (l.) and the epidemiology. in our studies, all in-use containers were treated at 8 g/1000 l, including smaller containers and animal feeders which were found to contribute 23% of ae aegypti pupae. the treated waters were subjected to routine water exchang ... | 2016 | 27627758 |
| pyriproxyfen and the microcephaly epidemic in brazil - an ecological approach to explore the hypothesis of their association. | the microcephaly epidemic in brazil generated intense debate regarding its causality, and one hypothesised cause of this epidemic, now recognised as congenital zika virus syndrome, was the treatment of drinking water tanks with pyriproxyfen to control aedes aegypti larvae. we present the results of a geographical analysis of the association between the prevalence of microcephaly confirmed by fenton growth charts and the type of larvicide used in the municipalities that were home to the mothers o ... | 2016 | 27812601 |
| insecticide substitutes for ddt to control mosquitoes may be causes of several diseases. | malaria continues to be a public health problem in bangladesh, despite efforts in the 1960s to eradicate the vectors through the use of ddt. at one point, eradication of malaria was acclaimed but later on it reappeared. the use of ddt is no more legally allowed in bangladesh, which has been officially replaced by a number organophosphates and/or synthetic pyrethroids and their combinations in addition to the integrated vector management (ivm) package. ivm being a community approach is still to g ... | 2012 | 22956113 |
| monitoring resistance to bacillus thuringiensis subsp. israelensis in the field by performing bioassays with each cry toxin separately. | bacillus thuringiensis subsp. israelensis (bti) is increasingly used worldwide for mosquito control and is the only larvicide used in the french rhône-alpes region since decades. the artificial selection of mosquitoes with field-persistent bti collected in breeding sites from this region led to a moderate level of resistance to bti, but to relatively high levels of resistance to individual bti cry toxins. based on this observation, we developed a bioassay procedure using each bti cry toxin separ ... | 0 | 24037105 |
| the susceptibility of aedes aegypti populations displaying temephos resistance to bacillus thuringiensis israelensis: a basis for management. | aedes aegypti is the vector of dengue virus, and its control is essential to prevent disease transmission. among the agents available to control this species, biolarvicides based on bacillus thuringiensis serovar israelensis (bti) are an effective alternative to replace the organophosphate temephos for controlling populations that display resistance to this insecticide. the major goal of this study was to determine the baseline susceptibility of brazilian ae. aegypti populations to bti, taking i ... | 2013 | 24499507 |
| resistance to bio-insecticides or how to enhance their sustainability: a review. | after more than 70 years of chemical pesticide use, modern agriculture is increasingly using biological control products. resistances to conventional insecticides are wide spread, while those to bio-insecticides have raised less attention, and resistance management is frequently neglected. however, a good knowledge of the limitations of a new technique often provides greater sustainability. in this review, we compile cases of resistance to widely used bio-insecticides and describe the associated ... | 2015 | 26150820 |
| characterization of a chitin-binding protein from bacillus thuringiensis hd-1. | strains of bacillus thuringiensis produce insecticidal proteins. these strains have been isolated from diverse ecological niches, such as soil, phylloplane, insect cadavers and grain dust. to effectively propagate, these strains produce a range of molecules that facilitate its multiplication in a competing environment. in this report, we have examined synthesis of a chitin-binding protein and evaluated its effect on fungi encountered in environment and its interaction with insecticidal proteins ... | 2013 | 23824872 |
| field efficacy of vectobac gr as a mosquito larvicide for the control of anopheline and culicine mosquitoes in natural habitats in benin, west africa. | the efficacy of vectobac gr (potency 200 itu/mg), a new formulation of bacterial larvicide bacillus thuringiensis var. israelensis strain am65-52, was evaluated against anopheles gambiae and culex quinquefasciatus in simulated field and natural habitats in benin. | 2014 | 24505334 |
| pyrosequencing the midgut transcriptome of the banana weevil cosmopolites sordidus (germar) (coleoptera: curculionidae) reveals multiple protease-like transcripts. | the banana weevil cosmopolites sordidus is an important and serious insect pest in most banana and plantain-growing areas of the world. in spite of the economic importance of this insect pest very little genomic and transcriptomic information exists for this species. in the present study, we characterized the midgut transcriptome of c. sordidus using massive 454-pyrosequencing. we generated over 590,000 sequencing reads that assembled into 30,840 contigs with more than 400 bp, representing a sig ... | 2016 | 26949943 |
| bacillus thuringiensis toxins: an overview of their biocidal activity. | bacillus thuringiensis (bt) is a gram positive, spore-forming bacterium that synthesizes parasporal crystalline inclusions containing cry and cyt proteins, some of which are toxic against a wide range of insect orders, nematodes and human-cancer cells. these toxins have been successfully used as bioinsecticides against caterpillars, beetles, and flies, including mosquitoes and blackflies. bt also synthesizes insecticidal proteins during the vegetative growth phase, which are subsequently secrete ... | 2014 | 25514092 |
| bacillus thuringiensis is an environmental pathogen and host-specificity has developed as an adaptation to human-generated ecological niches. | bacillus thuringiensis (bt) has been used successfully as a biopesticide for more than 60 years. more recently, genes encoding their toxins have been used to transform plants and other organisms. despite the large amount of research on this bacterium, its true ecology is still a matter of debate, with two major viewpoints dominating: while some understand bt as an insect pathogen, others see it as a saprophytic bacteria from soil. in this context, bt's pathogenicity to other taxa and the possibi ... | 2013 | 26462580 |
| domain iii of bacillus thuringiensis cry1ie toxin plays an important role in binding to peritrophic membrane of asian corn borer. | the insecticidal ie648 toxin is a truncated cry1ie protein with increased toxicity against asian corn borer (acb). cry toxins are pore-forming toxins that disrupt insect midgut cells to kill the larvae. however, the peritrophic membrane (pm) is an important barrier that cry toxins must cross before binding to midgut cells. previously, it was shown that cry toxins are able to bind and accumulate in the pm of several lepidopteran insects. binding of ie648 toxin to pm of acb was previously reported ... | 2015 | 26295704 |
| transcriptional cellular responses in midgut tissue of aedes aegypti larvae following intoxication with cry11aa toxin from bacillus thuringiensis. | although much is known about the mechanism of action of bacillus thuringiensis cry toxins, the target tissue cellular responses to toxin activity is less understood. previous transcriptomic studies indicated that significant changes in gene expression occurred during intoxication. however, most of these studies were done in organisms without a sequenced and annotated reference genome. a reference genome and transcriptome is available for the mosquito aedes aegypti, and its importance as a diseas ... | 2015 | 26645277 |
| draft genome sequences of two bacillus thuringiensis strains and characterization of a putative 41.9-kda insecticidal toxin. | in this work, we report the genome sequencing of two bacillus thuringiensis strains using illumina next-generation sequencing technology (ngs). strain hu4-2, toxic to many lepidopteran pest species and to some mosquitoes, encoded genes for two insecticidal crystal (cry) proteins, cry1ia and cry9ea, and a vegetative insecticidal protein (vip) gene, vip3ca2. strain leapi01 contained genes coding for seven cry proteins (cry1aa, cry1ca, cry1da, cry2ab, cry9ea and two cry1ia gene variants) and a vip3 ... | 2014 | 24784323 |
| identification and characterization of three previously undescribed crystal proteins from bacillus thuringiensis subsp. jegathesan. | the total protoxin complement in the parasporal body of mosquitocidal strain, bacillus thuringiensis subsp. jegathesan 367, 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 prot ... | 2013 | 23524673 |
| characterization and expression profiling of atp-binding cassette transporter genes in the diamondback moth, plutella xylostella (l.). | atp-binding cassette (abc) transporters are one of the major transmembrane protein families found in all organisms and play important roles in transporting a variety of compounds across intra and extra cellular membranes. in some species, abc transporters may be involved in the detoxification of substances such as insecticides. the diamondback moth, plutella xylostella (l.), a destructive pest of cruciferous crops worldwide, is an important species to study as it is resistant to many types of in ... | 2016 | 27678067 |
| anti-infective metabolites of a newly isolated bacillus thuringiensis kl1 associated with kalmegh (andrographis paniculata nees.), a traditional medicinal herb. | this study was conducted to isolate endophytic bacteria possessing anti-infective property from kalmegh (andrographis paniculata nees.), a well-known medicinal plant. a total of 23 strains were isolated from this plant among which the strain kl1, isolated from surface-sterilized leaf of this medicinal herb, showed broad-spectrum antagonism against an array of gram-positive and -negative bacterial pathogens. ethyl acetate extract of kl1-fermented media yielded a greenish amorphous substance retai ... | 2016 | 26997870 |
| the cry toxin operon of clostridium bifermentans subsp. malaysia is highly toxic to aedes larval mosquitoes. | the management and control of mosquito vectors of human disease currently rely primarily on chemical insecticides. however, larvicidal treatments can be effective, and if based on biological insecticides, they can also ameliorate the risk posed to human health by chemical insecticides. the aerobic bacteria bacillus thuringiensis and lysinibacillus sphaericus have been used for vector control for a number of decades. but a more cost-effective use would be an anaerobic bacterium because of the eas ... | 2014 | 25002432 |
| anthelmintic effect of bacillus thuringiensis strains against the gill fish trematode centrocestus formosanus. | parasitic agents, such as helminths, are the most important biotic factors affecting aquaculture, and the fluke centrocestus formosanus is considered to be highly pathogenic in various fish species. there have been efforts to control this parasite with chemical helminthicides, but these efforts have had unsuccessful results. we evaluated the anthelmintic effect of 37 strains of bacillus thuringiensis against c. formosanus metacercariae in vitro using two concentrations of total protein, and only ... | 2016 | 27294137 |
| a spodoptera exigua cadherin serves as a putative receptor for bacillus thuringiensis cry1ca toxin and shows differential enhancement of cry1ca and cry1ac toxicity. | crystal toxin cry1ca from bacillus thuringiensis has an insecticidal spectrum encompassing lepidopteran insects that are tolerant to current commercially used b. thuringiensis crops (bt crops) expressing cry1a toxins and may be useful as a potential bioinsecticide. the mode of action of cry1a is fairly well understood. however, whether cry1ca interacts with the same receptor proteins as cry1a remains unproven. in the present paper, we first cloned a cadherin-like gene, secad1b, from spodoptera e ... | 2013 | 23835184 |
| integrated mosquito larval source management reduces larval numbers in two highland villages in western kenya. | in western kenya, malaria remains one of the major health problems and its control remains an important public health measure. malaria control is by either use of drugs to treat patients infected with malaria parasites or by controlling the vectors. vector control may target the free living adult or aquatic (larval) stages of mosquito. the most commonly applied control strategies target indoor resting mosquitoes. however, because mosquitoes spend a considerable time in water, targeting the aquat ... | 2012 | 22607227 |
| the epidemiology of residual plasmodium falciparum malaria transmission and infection burden in an african city with high coverage of multiple vector control measures. | in the tanzanian city of dar es salaam, high coverage of long-lasting insecticidal nets (llins), larvicide application (la) and mosquito-proofed housing, was complemented with improved access to artemisinin-based combination therapy and rapid diagnostic tests by the end of 2012. | 2016 | 27216734 |
| immune-related transcriptome of coptotermes formosanus shiraki workers: the defense mechanism. | formosan subterranean termites, coptotermes formosanus shiraki, live socially in microbial-rich habitats. to understand the molecular mechanism by which termites combat pathogenic microbes, a full-length normalized cdna library and four suppression subtractive hybridization (ssh) libraries were constructed from termite workers infected with entomopathogenic fungi (metarhizium anisopliae and beauveria bassiana), gram-positive bacillus thuringiensis and gram-negative escherichia coli, and the libr ... | 2013 | 23874972 |
| bacillus thuringiensis cry1a toxins are versatile proteins with multiple modes of action: two distinct pre-pores are involved in toxicity. | cry proteins from bacillus thuringiensis are insecticidal pfts (pore-forming toxins). in the present study, we show that two distinct functional pre-pores of cry1ab are formed after binding of the protoxin or the protease-activated toxin to the cadherin receptor, but before membrane insertion. both pre-pores actively induce pore formation, although with different characteristics, and contribute to the insecticidal activity. we also analysed the oligomerization of the mutant cry1abmod protein. th ... | 0 | 24456341 |
| evolutionary diversification of aminopeptidase n in lepidoptera by conserved clade-specific amino acid residues. | members of the aminopepidase n (apn) gene family of the insect order lepidoptera (moths and butterflies) bind the naturally insecticidal cry toxins produced by the bacterium bacillus thuringiensis. phylogenetic analysis of amino acid sequences of seven lepidopteran apn classes provided strong support for the hypothesis that lepidopteran apn2 class arose by gene duplication prior to the most recent common ancestor of lepidoptera and diptera. the cry toxin-binding region (br) of lepidopteran and d ... | 2014 | 24675701 |
| division of labour and terminal differentiation in a novel bacillus thuringiensis strain. | a major challenge in bacterial developmental biology has been to understand the mechanisms underlying cell fate decisions. some differentiated cell types display cooperative behaviour. cooperation is one of the greatest mysteries of evolutionary biology and microbes have been considered as an excellent system for experimentally testing evolution theories. bacillus thuringiensis (bt) is a spore-forming bacterium, which is genetically closely related to b. anthracis, the agent of anthrax, and to b ... | 2014 | 25083932 |
| a toxin-binding alkaline phosphatase fragment synergizes bt toxin cry1ac against susceptible and resistant helicoverpa armigera. | evolution of resistance by insects threatens the continued success of pest control using insecticidal crystal (cry) proteins from the bacterium bacillus thuringiensis (bt) in sprays and transgenic plants. in this study, laboratory selection with cry1ac yielded five strains of cotton bollworm, helicoverpa armigera, with resistance ratios at the median lethal concentration (lc50) of activated cry1ac ranging from 22 to 1700. reduced activity and reduced transcription of an alkaline phosphatase prot ... | 2015 | 25885820 |
| insect pathogenic bacteria in integrated pest management. | the scientific community working in the field of insect pathology is experiencing an increasing academic and industrial interest in the discovery and development of new bioinsecticides as environmentally friendly pest control tools to be integrated, in combination or rotation, with chemicals in pest management programs. in this scientific context, market data report a significant growth of the biopesticide segment. acquisition of new technologies by multinational ag-tech companies is the center ... | 2015 | 26463190 |
| mapk signaling pathway alters expression of midgut alp and abcc genes and causes resistance to bacillus thuringiensis cry1ac toxin in diamondback moth. | insecticidal crystal toxins derived from the soil bacterium bacillus thuringiensis (bt) are widely used as biopesticide sprays or expressed in transgenic crops to control insect pests. however, large-scale use of bt has led to field-evolved resistance in several lepidopteran pests. resistance to bt cry1ac toxin in the diamondback moth, plutella xylostella (l.), was previously mapped to a multigenic resistance locus (btr-1). here, we assembled the 3.15 mb btr-1 locus and found high-level resistan ... | 2015 | 25875245 |
| gene expression patterns and sequence polymorphisms associated with mosquito resistance to bacillus thuringiensis israelensis toxins. | despite the intensive use of bacillus thuringiensis israelensis (bti) toxins for mosquito control, little is known about the long term effect of exposure to this cocktail of toxins on target mosquito populations. in contrast to the many cases of resistance to bacillus thuringiensis cry toxins observed in other insects, there is no evidence so far for bti resistance evolution in field mosquito populations. high fitness costs measured in a bti selected mosquito laboratory strain suggest that evolv ... | 2014 | 25341495 |
| bt toxin modification for enhanced efficacy. | insect-specific toxins derived from bacillus thuringiensis (bt) provide a valuable resource for pest suppression. here we review the different strategies that have been employed to enhance toxicity against specific target species including those that have evolved resistance to bt, or to modify the host range of bt crystal (cry) and cytolytic (cyt) toxins. these strategies include toxin truncation, modification of protease cleavage sites, domain swapping, site-directed mutagenesis, peptide additi ... | 2014 | 25340556 |
| functional characterizations of residues arg-158 and tyr-170 of the mosquito-larvicidal bacillus thuringiensis cry4ba. | the insecticidal activity of bacillus thuringiensis (bt) cry toxins involves toxin stabilization, oligomerization, passage across the peritrophic membrane (pm), binding to midgut receptors and pore-formation. the residues arg-158 and tyr-170 have been shown to be crucial for the toxicity of bt cry4ba. we characterized the biological function of these residues. in mosquito larvae, the mutants r158a/e/q (r158) could hardly penetrate the pm due to a significantly reduced ability to alter pm permeab ... | 0 | 24286331 |
| alkaline phosphatases and aminopeptidases are altered in a cry11aa resistant strain of aedes aegypti. | bacillus thuringiensis subsp. israelensis (bti) is widely used for the biological control of mosquito populations. however, the mechanism of bti toxins is still not fully understood. to further elucidate the mechanism of bti toxins, we developed an aedes aegypti resistant strain that shows high-level resistance to cry11aa toxin. after 27 selections with cry11aa toxin, the larvae showed a 124-fold resistance ratio for cry11aa (strain g30). g30 larvae showed cross-resistance to cry4aa (66-fold res ... | 2014 | 25242559 |
| proteomic analysis of cry2aa-binding proteins and their receptor function in spodoptera exigua. | the bacterium bacillus thuringiensis produces crystal (cry) proteins that are toxic to a diverse range of insects. transgenic crops that produce bt cry proteins are grown worldwide because of their improved resistance to insect pests. although bt "pyramid" cotton that produces both cry1a and cry2a is predicted to be more resistant to several lepidopteran pests, including spodoptera exigua, than plants that produce cry1ac alone, the mechanisms responsible for the toxicity of cry2aa in s. exigua a ... | 2017 | 28067269 |
| transcriptional analysis of susceptible and resistant european corn borer strains and their response to cry1f protoxin. | despite a number of recent reports of insect resistance to transgenic crops expressing insecticidal toxins from bacillus thuringiensis (bt), little is known about the mechanism of resistance to these toxins. the purpose of this study is to identify genes associated with the mechanism of cry1f toxin resistance in european corn borer (ostrinia nubilalis hübner). for this, we compared the global transcriptomic response of laboratory selected resistant and susceptible o. nubilalis strain to cry1f to ... | 2015 | 26220297 |
| pest control and resistance management through release of insects carrying a male-selecting transgene. | development and evaluation of new insect pest management tools is critical for overcoming over-reliance upon, and growing resistance to, synthetic, biological and plant-expressed insecticides. for transgenic crops expressing insecticidal proteins from the bacterium bacillus thuringiensis ('bt crops') emergence of resistance is slowed by maintaining a proportion of the crop as non-bt varieties, which produce pest insects unselected for resistance. while this strategy has been largely successful, ... | 2015 | 26179401 |
| effects of periplocoside p from periploca sepium on the midgut transmembrane potential of mythimna separata larvae. | periplocoside p (psp) isolated from the root bark of periploca sepium contains a pregnane glycoside skeleton and possesses high insecticidal properties. preliminary studies indicated that psp disrupts epithelial functions in the midgut of lepidopteran larvae. in the present study, we examined the effects of psp on the apical and basolateral membrane voltages, va and vbl, respectively, of cells from (1) midguts isolated from the larvae of the oriental armyworm mythimna separata that were in vitro ... | 2016 | 27833169 |
| bacillus thuringiensis cyt2aa2 toxin disrupts cell membranes by forming large protein aggregates. | bacillus thuringiensis (bt) cyt2aa2 showed toxicity against dipteran insect larvae and in vitro lysis activity on several cells. it has potential applications in the biological control of insect larvae. although pore-forming and/or detergent-like mechanisms were proposed, the mechanism underlying cytolytic activity remains unclear. analysis of the haemolytic activity of cyt2aa2 with osmotic stabilizers revealed partial toxin inhibition, suggesting a distinctive mechanism from the putative pore f ... | 2016 | 27612497 |
| insect resistance to bacillus thuringiensis toxin cry2ab is conferred by mutations in an abc transporter subfamily a protein. | the use of conventional chemical insecticides and bacterial toxins to control lepidopteran pests of global agriculture has imposed significant selection pressure leading to the rapid evolution of insecticide resistance. transgenic crops (e.g., cotton) expressing the bt cry toxins are now used world wide to control these pests, including the highly polyphagous and invasive cotton bollworm helicoverpa armigera. since 2004, the cry2ab toxin has become widely used for controlling h. armigera, often ... | 2015 | 26583651 |
| the susceptibility of five african anopheles species to anabaena pcc 7120 expressing bacillus thuringiensis subsp. israelensis mosquitocidal cry genes. | malaria, one of the leading causes of death in africa, is transmitted by the bite of an infected female anopheles mosquito. problems associated with the development of resistance to chemical insecticides and concerns about the non-target effects and persistence of chemical insecticides have prompted the development of environmentally friendly mosquito control agents. the aim of this study was to evaluate the larvicidal activity of a genetically engineered cyanobacterium, anabaena pcc 7120#11, ag ... | 2012 | 23036082 |
| characterization of cdnas encoding serine proteases and their transcriptional responses to cry1ab protoxin in the gut of ostrinia nubilalis larvae. | serine proteases, such as trypsin and chymotrypsin, are the primary digestive enzymes in lepidopteran larvae, and are also involved in bacillus thuringiensis (bt) protoxin activation and protoxin/toxin degradation. we isolated and sequenced 34 cdnas putatively encoding trypsins, chymotrypsins and their homologs from the european corn borer (ostrinia nubilalis) larval gut. our analyses of the cdna-deduced amino acid sequences indicated that 12 were putative trypsins, 12 were putative chymotrypsin ... | 2012 | 22952884 |
| decreased toxicity of bacillus thuringiensis subsp. israelensis to mosquito larvae after contact with leaf litter. | bacillus thuringiensis subsp. israelensis is a bacterium producing crystals containing cry and cyt proteins, which are toxic for mosquito larvae. nothing is known about the interaction between crystal toxins and decaying leaf litter, which is a major component of several mosquito breeding sites and represents an important food source. in the present work, we investigated the behavior of b. thuringiensis subsp. israelensis toxic crystals sprayed on leaf litter. in the presence of leaf litter, a 6 ... | 2012 | 22610426 |
| potential prepore trimer formation by the bacillus thuringiensis mosquito-specific toxin: molecular insights into a critical prerequisite of membrane-bound monomers. | the insecticidal feature of the three-domain cry δ-endotoxins from bacillus thuringiensis is generally attributed to their capability to form oligomeric pores, causing lysis of target larval midgut cells. however, the molecular description of their oligomerization process has not been clearly defined. here a stable prepore of the 65-kda trypsin-activated cry4ba mosquito-specific toxin was established through membrane-mimetic environments by forming an ∼200-kda octyl-β-d-glucoside micelle-induced ... | 2015 | 26112409 |
| comprehensive analysis of gene expression profiles of the beet armyworm spodoptera exigua larvae challenged with bacillus thuringiensis vip3aa toxin. | host-pathogen interactions result in complex relationship, many aspects of which are not completely understood. vip proteins, which are bacillus thuringensis (bt) insecticidal toxins produced during the vegetative stage, are selectively effective against specific insect pests. this new group of bt proteins represents an interesting alternative to the classical bt cry toxins because current data suggests that they do not share the same mode of action. we have designed and developed a genome-wide ... | 2013 | 24312604 |
| membrane binding and oligomer membrane insertion are necessary but insufficient for bacillus thuringiensis cyt1aa toxicity. | bacillus thuringiensis cyt proteins are pore-forming toxins that have insecticidal activity mainly against dipteran insects. however, certain cyt proteins have toxicity to some insect orders, but not toxicity of cyt1aa against lepidopteran larvae has been found. insect specificity has been proposed to rely in specific binding to certain lipids on the brush border membrane of midgut cells since no protein receptors have been described so far. to determine the molecular basis of cyt1aa insect spec ... | 2013 | 24512949 |
| mtx toxins from lysinibacillus sphaericus enhance mosquitocidal cry-toxin activity and suppress cry-resistance in culex quinquefasciatus. | the interaction of mtx toxins from lysinibacillus sphaericus (formerly bacillus sphaericus) with bacillus thuringiensis subsp. israelensis cry toxins and the influence of such interactions on cry-resistance were evaluated in susceptible and cry-resistant culex quinquefasciatus larvae. mtx-1 and mtx-2 were observed to be active against both susceptible and resistant mosquitoes; however varying levels of cross-resistance toward mtx toxins were observed in the resistant mosquitoes. a 1:1 mixture of ... | 2013 | 24144574 |
| a 104 kda aedes aegypti aminopeptidase n is a putative receptor for the cry11aa toxin from bacillus thuringiensis subsp. israelensis. | the cry11aa protein produced in bacillus thuringiensis subsp. israelensis, a bacterial strain used worldwide for the control of aedes aegypti larvae, binds midgut brush border membrane vesicles (bbmv) with an apparent k(d) of 29.8 nm. previously an aminopeptidase n (apn), named aaeapn2, was identified as a putative cry11aa toxin binding protein by pull-down assays using biotinylated cry11aa toxin (chen et al., 2009. insect biochem. mol. biol. 39, 688-696). here we show this protein localizes to ... | 2013 | 24128608 |
| different effects of bacillus thuringiensis toxin cry1ab on midgut cell transmembrane potential of mythimna separata and agrotis ipsilon larvae. | bacillus thuringiensis (bt) cry toxins from the cry1a family demonstrate significantly different toxicities against members of the family noctuidae for unknown reasons. in this study, membrane potential was measured and analyzed in freshly isolated midgut samples from mythimna separata and agrotis ipsilon larvae under oral administration and in vitro incubation with bt toxin cry1ab to elucidate the mechanism of action for further control of these pests. bioassay results showed that the larvae of ... | 2015 | 26694463 |
| genome sequence of the mosquitocidal bacillus thuringiensis strain br58, a biopesticide product effective against the coffee berry borer (hypothenemus hampei). | bacillus thuringiensis is an important microbial control agent against insect pests. the draft genome sequence of the brazilian strain br58 described here contains the insecticidal genes cry4a, cry4b, cry10a, cry11a, cry60a, cry60b, and cyt1a, which show toxicity to both aedes aegypti and hypothenemus hampei larvae. | 2015 | 26659669 |
| aedes cadherin mediates the in vivo toxicity of the cry11aa toxin to aedes aegypti. | cadherin plays an important role in the toxicity of bacillus thuringiensis cry proteins. we previously cloned a full-length cadherin from aedes aegypti larvae and reported this protein binds cry11aa toxin from b. thuringiensis subsp. israelensis with high affinity, ≈16.7nm. based on these results, we investigated if aedes cadherin is involved in the in vivo toxicity of cry11aa toxin to ae. aegypti. we established a mosquito cell line stably expressing the full-length aedes cadherin and transgeni ... | 2014 | 25064814 |
| essential oils from two eucalyptus from tunisia and their insecticidal action on orgyia trigotephras (lepidotera, lymantriidae). | essential oils extracted from aromatic and medicinal plants have many biological properties and are therefore an alternative to the use of synthetic products. the chemical composition of essential oils from two medicinal plants (eucalyptus globulus and e. lehmannii) was determined and, their insecticidal effects on the third and fourth larval stages of orgyia trigotephras were assessed. | 0 | 25204015 |
| evaluation of different culture media for improvement in bioinsecticides production by indigenous bacillus thuringiensis and their application against larvae of aedes aegypti. | production of indigenous isolate bacillus thuringiensis sv2 (bt sv2) was checked on conventional and nonconventional carbon and nitrogen sources in shake flasks. the effects on the production of biomass, toxin production, and spore formation capability of mosquito toxic strain were determined. toxicity differs within the same strain depending on the growth medium. bt sv2 produced with pigeon pea and soya bean flour were found highly effective with lc50 < 4 ppm against larvae of aedes aegypti. th ... | 2014 | 24592157 |
| aedes aegypti mos20 cells internalizes cry toxins by endocytosis, and actin has a role in the defense against cry11aa toxin. | bacillus thuringiensis (bt) cry toxins are used to control aedes aegypti, an important vector of dengue fever and yellow fever. bt cry toxin forms pores in the gut cells, provoking larvae death by osmotic shock. little is known, however, about the endocytic and/or degradative cell processes that may counteract the toxin action at low doses. the purpose of this work is to describe the mechanisms of internalization and detoxification of cry toxins, at low doses, into mos20 cells from a. aegypti, f ... | 2014 | 24476709 |
| retargeting of the bacillus thuringiensis toxin cyt2aa against hemipteran insect pests. | although transgenic crops expressing bacillus thuringiensis (bt) toxins have been used successfully for management of lepidopteran and coleopteran pest species, the sap-sucking insects (hemiptera) are not particularly susceptible to bt toxins. to overcome this limitation, we demonstrate that addition of a short peptide sequence selected for binding to the gut of the targeted pest species serves to increase toxicity against said pest. insertion of a 12-aa pea aphid gut-binding peptide by adding t ... | 2013 | 23650347 |
| transcriptome of the lymantria dispar (gypsy moth) larval midgut in response to infection by bacillus thuringiensis. | transcriptomic profiles of the serious lepidopteran insect pest lymantria dispar (gypsy moth) were characterized in the larval midgut in response to infection by bacillus thuringiensis kurstaki, a biopesticide commonly used for its control. rna-seq approaches were used to define a set of 49,613 assembled transcript sequences, of which 838, 1,248 and 3,305 were respectively partitioned into high-, mid- and low-quality tiers on the basis of homology information. digital gene expression profiles su ... | 2013 | 23658687 |
| role of upr pathway in defense response of aedes aegypti against cry11aa toxin from bacillus thuringiensis. | the insecticidal cry toxins are pore-forming toxins produced by the bacteria bacillus thuringiensis that disrupt insect-midgut cells. cells can trigger different survival mechanisms to counteract the effects of sub-lytic doses of pore forming toxins. particularly, two signaling pathways have been demonstrated to play a role in the defense mechanism to other toxins in caenorhabditis elegans and in mammalian cells. these are the unfolded protein response (upr) and the sterol regulatory element bin ... | 2013 | 23594997 |
| bacillus thuringiensis var. israelensis misting for control of aedes in cryptic ground containers in north queensland, australia. | in australia, dengue is not endemic, although the vector mosquito aedes aegypti is established in far north queensland (fnq). aedes albopictus has recently invaded the torres strait region, but is not established on mainland australia. to maintain dengue-free, public health departments in fnq closely monitor introduced dengue infections and confine outbreaks through rigorous vector control responses. to safeguard mainland australia from ae. albopictus establishment, pre-emptive strategies are re ... | 2013 | 23358637 |
| understanding the long-lasting attraction of malaria mosquitoes to odor baits. | the use of odor baits for surveillance and control of malaria mosquitoes requires robust dispensing tools. in this study, the residual activity of a synthetic mosquito attractant blend dispensed from nylon or low density polyethylene (ldpe) sachets was evaluated at weekly intervals for one year without re-impregnation. the potential role of bacteria in modulating the attraction of mosquitoes to odor-treated nylon that had been used repeatedly over the one year study period, without re-impregnati ... | 2015 | 25798818 |
| crygetter: a tool to automate retrieval and analysis of cry protein data. | for many years, the use of chemical agents to control crop pests has been degrading the environment, bringing problems to humans and all living things. an alternative to deal with the pests is the use of biopesticides, biological agents capable of controlling these harmful organisms. one kind of biopesticide is bacillus thuringiensis, a gram-positive bacterium that synthesizes a protein that, when ingested by the pests, kills them and does not harm other species. | 2016 | 27578522 |
| isoleucine at position 150 of cyt2aa toxin from bacillus thuringiensis plays an important role during membrane binding and oligomerization. | cyt2aa2 is a mosquito larvicidal and cytolytic toxin produced by bacillus thuringiensis subsp. darmstadiensis. the toxin becomes inactive when isoleucine at position 150 was replaced by alanine. to investigate the functional role of this position, ile150 was substituted with leu, phe, glu and lys. all mutant proteins were produced at high level, solubilized in carbonate buffer and yielded protease activated product similar to those of the wild type. intrinsic fluorescence spectra analysis sugges ... | 0 | 23527862 |
| toxicity studies for indigenous bacillus thuringiensis isolates from malang city, east java on aedes aegypti larvae. | to investigate the toxicity of indigenous bacillus thuringiensis (b. thuringiensis)isolates from malang city for controlling aedes aegypti (ae. aegypti) larvae. | 0 | 23593589 |
| proteome response of tribolium castaneum larvae to bacillus thuringiensis toxin producing strains. | susceptibility of tribolium castaneum (tc) larvae was determined against spore-crystal mixtures of five coleopteran specific and one lepidopteran specific bacillus thuringiensis cry toxin producing strains and those containing the structurally unrelated cry3ba and cry23aa/cry37aa proteins were found toxic (lc(50) values 13.53 and 6.30 µg spore-crystal mixture/µl flour disc, respectively). using itraq combined with lc-ms/ms allowed the discovery of seven novel differentially expressed proteins in ... | 2013 | 23372850 |
| a transgenic approach for controlling lygus in cotton. | lygus species of plant-feeding insects have emerged as economically important pests of cotton in the united states. these species are not controlled by commercial bacillus thuringiensis (bt) cotton varieties resulting in economic losses and increased application of insecticide. previously, a bt crystal protein (cry51aa2) was reported with insecticidal activity against lygus spp. however, transgenic cotton plants expressing this protein did not exhibit effective protection from lygus feeding dama ... | 2016 | 27426014 |
| genome wide discovery of long intergenic non-coding rnas in diamondback moth (plutella xylostella) and their expression in insecticide resistant strains. | long non-coding rnas (lncrnas) play important roles in genomic imprinting, cancer, differentiation and regulation of gene expression. here, we identified 3844 long intergenic ncrnas (lincrna) in plutella xylostella, which is a notorious pest of cruciferous plants that has developed field resistance to all classes of insecticides, including bacillus thuringiensis (bt) endotoxins. further, we found that some of those lincrnas may potentially serve as precursors for the production of small ncrnas. ... | 2015 | 26411386 |
| the novel abc transporter abch1 is a potential target for rnai-based insect pest control and resistance management. | insect pests cause serious crop damage and develop high-level resistance to chemical insecticides and bacillus thuringiensis (bt) insecticidal cry toxins. a new promising approach for controlling them and overcoming this resistance is rna interference (rnai). the rnai-based insect control strategy depends on the selection of suitable target genes. in this study, we cloned and characterized a novel abc transporter gene pxabch1 in diamondback moth, plutella xylostella (l.). phylogenetic analysis s ... | 2015 | 26333918 |
| draft genome sequence of bacillus thuringiensis 147, a brazilian strain with high insecticidal activity. | bacillus thuringiensis is a ubiquitous gram-positive and sporulating bacterium. its crystals and secreted toxins are useful tools against larvae of diverse insect orders and, as a consequence, an alternative to recalcitrant chemical insecticides. we report here the draft genome sequence of b. thuringiensis147, a strain isolated from brazil and with high insecticidal activity. the assembled genome contained 6,167,994 bp and was distributed in seven replicons (a chromosome and 6 plasmids). we iden ... | 0 | 26517667 |
| characterization of cry2-type genes of bacillus thuringiensis strains from soilisolated of sichuan basin, china. | sichuan basin, situated in the west of china, is the fourth biggest basin in china. in order to describe a systematic study of the cry2-type genes resources from bacillus thuringiensis strains of sichuan basin, a total of 791 bacillus thuringiensis strains have been screened from 2650 soil samples in different ecological regions. the method of pcr-restriction fragment length polymorphism (pcr-rflp) was used to identify the type of cry2 genes. the results showed that 322 bacillus thuringiensis st ... | 0 | 24031615 |
| aedes aegypti alkaline phosphatase alp1 is a functional receptor of bacillus thuringiensis cry4ba and cry11aa toxins. | bacillus thuringiensis subs. israelensis produces at least three cry toxins (cry4aa, cry4ba, and cry11aa) that are active against aedes aegypti larvae. previous work characterized a gpi-anchored alkaline phosphatase (alp1) as a cry11aa binding molecule from the gut of a. aegypti larvae. we show here that cry4ba binds alp1, and that the binding and toxicity of cry4ba mutants located in loop 2 of domain ii is correlated. also, we analyzed the contribution of alp1 toward the toxicity of cry4ba and ... | 2012 | 22728570 |
| larval midgut modifications associated with bti resistance in the yellow fever mosquito using proteomic and transcriptomic approaches. | bacillus thuringiensis var. israelensis (bti) is a natural larval mosquito pathogen producing pore-forming toxins targeting the midgut of diptera larvae. it is used worldwide for mosquito control. resistance mechanisms of an aedes aegypti laboratory strain selected for 30 generations with field-collected leaf litter containing bti toxins were investigated in larval midguts at two levels: 1. gene transcription using dna microarray and rt-qpcr and 2. differential expression of brush border membran ... | 2012 | 22703117 |
| comparative proteomic analysis of aedes aegypti larval midgut after intoxication with cry11aa toxin from bacillus thuringiensis. | cry toxins produced by bacillus thuringiensis bacteria are environmentally safe alternatives to control insect pests. they are pore-forming toxins that specifically affect cell permeability and cellular integrity of insect-midgut cells. in this work we analyzed the defensive response of aedes aegypti larva to cry11aa toxin intoxication by proteomic and functional genomic analyses. two dimensional differential in-gel electrophoresis (2d-dige) was utilized to analyze proteomic differences among a. ... | 2012 | 22615881 |
| cadherin binding is not a limiting step for bacillus thuringiensis subsp. israelensis cry4ba toxicity to aedes aegypti larvae. | 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) wi ... | 0 | 22329749 |
| characterization of insecticidal genes of bacillus thuringiensis strains isolated from arid environments. | this study aimed at characterizing the insecticidal genes of eight bacillus thuringiensis isolates that were recovered from the local environment of western saudi arabia. the screening for the presence of lepidopteran-specific cry1a family and vip3a genes, dipteran-specific cry4 family and coleopteran-specific cry3a, vip1a and vip2a genes, was carried out by pcr. all eight isolates produced pcr products that confirmed the presence of cry1aa, cry1ab, cry1ac, cry4a, cry4b genes, but not cry3a, vip ... | 2012 | 23997347 |
| oligomerization is a key step in cyt1aa membrane insertion and toxicity but not necessary to synergize cry11aa toxicity in aedes aegypti larvae. | bacillus thuringiensis produces insecticidal cry and cyt proteins that are toxic to different insect orders. in addition, cyt toxins also display haemolytic activity. both toxins are pore-forming proteins that form oligomeric structures that insert into the target membrane to lyse cells. cyt toxins play an important role in mosquitocidal activity since they synergize cry toxins and are able to overcome resistance to cry toxins. cry and cyt toxins interact by specific epitopes, and this interacti ... | 2013 | 24112611 |
| investigating the genetics of bti resistance using mrna tag sequencing: application on laboratory strains and natural populations of the dengue vector aedes aegypti. | mosquito control is often the main method used to reduce mosquito-transmitted diseases. in order to investigate the genetic basis of resistance to the bio-insecticide bacillus thuringiensis subsp. israelensis (bti), we used information on polymorphism obtained from cdna tag sequences from pooled larvae of laboratory bti-resistant and susceptible aedes aegypti mosquito strains to identify and analyse 1520 single nucleotide polymorphisms (snps). of the 372 snps tested, 99.2% were validated using d ... | 2013 | 24187584 |
| chemical and biological insecticides select distinct gene expression patterns in aedes aegypti mosquito. | worldwide evolution of mosquito resistance to chemical insecticides represents a major challenge for public health, and the future of vector control largely relies on the development of biological insecticides that can be used in combination with chemicals (integrated management), with the expectation that populations already resistant to chemicals will not become readily resistant to biological insecticides. however, little is known about the metabolic pathways affected by selection with chemic ... | 0 | 25540155 |
| differential proteomic analysis of trichoplusia ni cells after continuous selection with activated cry1ac toxin. | development of insect resistance to bacillus thuringiensis (bt) toxins threatens the sustained successful application of bt-based biological control tactics. multi-mechanisms of resistance have been proposed, such as alteration of toxin-binding proteins, changes of proteases in midgut and so on. the other responses of the cry1ac-selected insects might also contribute to the evolution of resistance. here, the cry1ac-selected trichoplusia ni tnh5 cells with high resistance were subjected to analys ... | 2012 | 23070538 |
| evolution of bacillus thuringiensis cry toxins insecticidal activity. | insecticidal cry proteins produced by bacillus thuringiensis are use worldwide in transgenic crops for efficient pest control. among the family of cry toxins, the three domain cry family is the better characterized regarding their natural evolution leading to a large number of cry proteins with similar structure, mode of action but different insect specificity. also, this group is the better characterized regarding the study of their mode of action and the molecular basis of insect specificity. ... | 2012 | 22463726 |
| fate of bacillus thuringiensis subsp. israelensis in the field: evidence for spore recycling and differential persistence of toxins in leaf litter. | bacillus thuringiensis subsp. israelensis is a bioinsecticide increasingly used worldwide for mosquito control. despite its apparent low level of persistence in the field due to the rapid loss of its insecticidal activity, an increasing number of studies suggested that the recycling of b. thuringiensis subsp. israelensis can occur under specific, unknown conditions. decaying leaf litters sampled in mosquito breeding sites in the french rhône-alpes region several months after a treatment were sho ... | 2012 | 23001669 |
| proteome analysis of cry4ba toxin-interacting aedes aegypti lipid rafts using gelc-ms/ms. | lipid rafts are microdomains in the plasma membrane of eukaryotic cells. among their many functions, lipid rafts are involved in cell toxicity caused by pore forming bacterial toxins including bacillus thuringiensis (bt) cry toxins. we isolated lipid rafts from brush border membrane vesicles (bbmv) of aedes aegypti larvae as a detergent resistant membrane (drm) fraction on density gradients. cholesterol, aminopeptidase (apn), alkaline phosphatase (alp) and the raft marker flotillin were preferen ... | 2012 | 23153095 |
| the effectiveness of trypsin modulating oostatic factor (tmof) and combination of tmof with bacillus thuringiensis against aedes aegypti larvae in the laboratory. | trypsin modulating oostatic factor (tmof) terminates trypsin biosynthesis in adult and larval mosquito gut. it will inhibit the growth and development of mosquito larvae feeding on it resulting in death by starvation. the objective of this study is to determine the effective dose of pichia-tmof and the combination of pichia-tmof with bacillus thuringiensis (bt) as larvicide on ae. aegypti larvae. | 2011 | 22808406 |
| strategies of a thirteen year surveillance programme on aedes albopictus (stegomyia albopicta) in southern switzerland. | in ticino, a canton located south of the alps in switzerland, a surveillance programme on aedes albopictus (stegomyia albopicta) started in 2000 seeing that the region was considered at high risk of introduction based on the rapid spread of this mosquito in neighbouring italy. | 2015 | 25890173 |