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Aedes aegypti bacillus thuringiensis

Catherine A Pruszynski, Lawrence J Hribar, Robert Mickle, Andrea L Leal
BACKGROUND: Aedes aegypti is a container-inhabiting mosquito and a vector of dengue, chikungunya, and Zika viruses. In 2009 several cases of autochthonous dengue transmission were reported in Key West, Florida, USA prompting a comprehensive response to control A. aegypti. In Key West, larvae of this mosquito develop in containers around human habitations which can be numerous and labor intensive to find and treat. Aerial applications of larvicide covering large areas in a short time can be an efficient and economical method to control A...
2017: PloS One
Daniella Goindin, Christelle Delannay, Andric Gelasse, Cédric Ramdini, Thierry Gaude, Frédéric Faucon, Jean-Philippe David, Joël Gustave, Anubis Vega-Rua, Florence Fouque
BACKGROUND: In the Guadeloupe and Saint Martin islands, Aedes aegypti mosquitoes are the only recognized vectors of dengue, chikungunya, and Zika viruses. For around 40 years, malathion was used as a mosquito adulticide and temephos as a larvicide. Since the European Union banned the use of these two insecticide molecules in the first decade of the 21st century, deltamethrin and Bacillus thuringiensis var. israelensis are the remaining adulticide and larvicide, respectively, used in Guadeloupe...
February 10, 2017: Infectious Diseases of Poverty
Ramalingam Karthik Raja, Dilipkumar Aiswarya, Baris Gulcu, Manickam Raja, Pachiappan Perumal, Sivaperumal Sivaramakrishnan, Harry K Kaya, Selcuk Hazir
The symbiotic bacteria, Photorhabdus and Xenorhabdus associated with entomopathogenic nematodes (EPNs) in the genera Heterorhabditis and Steinernema, respectively, produce a compound(s) called the Scavenging Deterrent Factor (SDF). SDF deters a number of terrestrial insect scavengers and predators and one bird species from feeding on host insects killed by the nematode-bacterium complex but has not been tested against aquatic vertebrates. Moreover, the Heterorhabditis-Photorhabdus association is believed to have evolved in an aquatic environment...
November 29, 2016: Journal of Invertebrate Pathology
Carine Ngoagouni, Basile Kamgang, Cécile Brengues, Gildas Yahouedo, Christophe Paupy, Emmanuel Nakouné, Mirdad Kazanji, Fabrice Chandre
BACKGROUND: 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 insecticides of Ae...
November 24, 2016: Parasites & Vectors
Maria de Fatima P Militão de Albuquerque, Wayner V de Souza, Antônio da Cruz G Mendes, Tereza M Lyra, Ricardo Aa Ximenes, Thália Vb Araújo, Cynthia Braga, Demócrito B Miranda-Filho, Celina Mt Martelli, Laura C Rodrigues
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 of the affected newborns in the metropolitan region of Recife in Pernambuco, the state in Brazil where the epidemic was first detected...
December 2016: Memórias do Instituto Oswaldo Cruz
Anna Likos, Isabel Griffin, Andrea M Bingham, Danielle Stanek, Marc Fischer, Stephen White, Janet Hamilton, Leah Eisenstein, David Atrubin, Prakash Mulay, Blake Scott, Patrick Jenkins, Danielle Fernandez, Edhelene Rico, Leah Gillis, Reynald Jean, Marshall Cone, Carina Blackmore, Janet McAllister, Chalmers Vasquez, Lillian Rivera, Celeste Philip
During the first 6 months of 2016, large outbreaks of Zika virus disease caused by local mosquito-borne transmission occurred in Puerto Rico and other U.S. territories, but local mosquito-borne transmission was not identified in the continental United States (1,2). As of July 22, 2016, the Florida Department of Health had identified 321 Zika virus disease cases among Florida residents and visitors, all occurring in either travelers from other countries or territories with ongoing Zika virus transmission or sexual contacts of recent travelers...
September 30, 2016: MMWR. Morbidity and Mortality Weekly Report
To Setha, Ngan Chantha, Seleena Benjamin, Doung Socheat
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 exchange activities...
September 2016: PLoS Neglected Tropical Diseases
Marimuthu Govindarajan, Periasamy Vijayan, Shine Kadaikunnan, Naiyf S Alharbi, Giovanni Benelli
Currently, mosquito vector control is facing a number of key challenges, including the rapid development of resistance to synthetic pesticides and the recent spread of aggressive arbovirus outbreaks. The biosynthesis of silver nanoparticles (AgNPs) is currently considered an environmental friendly alternative to the employ of pyrethroids, carbamates and microbial agents (e.g. Bacillus thuringiensis var. israelensis), since AgNPs are easy to produce, effective and stable in the aquatic environment. However, their biophysical features showed wide variations according to the botanical agent using for the green synthesis, outlining the importance of screening local floral resources used as reducing and stabilizing agents...
September 2016: Journal of Photochemistry and Photobiology. B, Biology
Renaud Stalinski, Frederic Laporte, Guillaume Tetreau, Laurence Després
Bacillus thuringiensis israelensis (Bti) toxins are increasingly used for mosquito control, but little is known about the precise mode of action of each of these toxins, and how they interact to kill mosquito larvae. By using RNA sequencing, we investigated change in gene transcription level and polymorphism variations associated with resistance to each Bti Cry toxin and to the full Bti toxin mixture in the dengue vector Aedes aegypti. The up-regulation of genes related to chitin metabolism in all selected strain suggests a generalist, non-toxin-specific response to Bti selection in Aedes aegypti...
October 2016: Infection, Genetics and Evolution
Paula V Gonzalez, Laura Harburguer, Paola A González-Audino, Héctor M Masuh
Aedes aegypti (L.) is an important dengue, chikungunya, and yellow fever vector. Immature stages of this species inhabit human-made containers placed in residential landscapes, and the application of larvicides inside containers that cannot be eliminated is still considered a priority in control programs. Larvicidal efficacy is influenced by several factors, including the formulation used, the water quality, and the susceptibility of larvae, among others. If an attractant can be incorporated into a slow-release larvicide formulation, it will be feasible to direct the larvae into the source of insecticide and thereby improving its efficacy...
June 2016: Parasitology Research
Jihen Elleuch, Samir Jaoua, Carole Ginibre, Fabrice Chandre, Slim Tounsi, Raida Z Zghal
BACKGROUND: Bacillus thuringiensis δ-endotoxins are the most widely used biopesticides for controlling economically important crop pests and disease vectors. Improving their efficacy is of great benefit. Here, an improvement in Cry2Aa δ-endotoxin toxicity was attempted via a cry gene over expression system using P20 from B. thuringiensis israelensis. RESULTS: The coexpression of Cry2Aa with P20 resulted in a seven fold increase in its production yield in B. thuringiensis...
December 2016: Pest Management Science
Barry W Alto, Cynthia C Lord
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 in conjunction with other sources of mosquito mortality in nature...
February 2016: PLoS Neglected Tropical Diseases
Guang-jie Han, Chuan-ming Li, Jun Sun, Qin Liu, Song Zhao, Jian-hang Qi, Jian Xu
OBJECTIVE: To investigate the effect of Bacillus thuringiensis var. israelensis (Bti) on the activities of three detoxification enzymes of Culex pipiens pallens and Aedes aegypti larvae. METHODS: The activities of glutathione transferase, acetyl cholinesterase and carboxyl esterase, were detected after two kinds of mosquito larvae were treated by Bti at different time and concentrations. RESULTS: The activities of three detoxification enzymes of the two kinds of mosquito larvae were influenced by Bti treatment...
August 2015: Zhongguo Xue Xi Chong Bing Fang Zhi za Zhi, Chinese Journal of Schistosomiasis Control
Autaipohn Kaikaew, Chamras Promptmas, Chanan Angsuthanasombat
Bacillus thuringiensis Cry4Ba mosquito-active toxin was previously shown to utilize two critical loop-residues, Tyr(332) and Phe(364) which are respectively located in β2-β3 and β4-β5 loops, for synergistic interactions with its alternative receptor-Cyt2Aa2. Here, structural analysis of the Cry4Ba-receptor-binding domain revealed that its N-terminal subdomain encompasses β2-β3 and β4-β5 hairpins which are stabilized by inter-hairpin hydrogen bonding between Thr(328) in β2 and Thr(369) in β5. Functional importance of these two side-chains was demonstrated by single-Ala substitutions (T328A and T369A), adversely affecting toxin activity against Aedes aegypti larvae...
January 15, 2016: Biochemical and Biophysical Research Communications
Renaud Stalinski, Frédéric Laporte, Laurence Després, Guillaume Tetreau
Bacillus thuringiensis subsp. israelensis (Bti) is a natural pathogen of dipterans widely used as a biological insecticide for mosquito control. To characterize the response of mosquitoes to intoxication with Bti, the transcriptome profile of Bti-exposed susceptible Aedes aegypti larvae was analysed using Illumina RNA-seq. Gene expression of 11 alkaline phosphatases (ALPs) was further investigated by real time quantitative polymerase chain reaction and ALP activity was measured in the susceptible strain and in four strains resistant to a single Bti Cry toxin or to Bti...
March 2016: Environmental Microbiology
Janaina Zorzetti, Ana P S Ricietto, Carlos R M da Silva, Ivan R Wolf, Gislayne T Vilas-Bôas, Pedro M O J Neves, Ana M Meneguim, Laurival A Vilas-Boas
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: Genome Announcements
Pablo Emiliano Canton, Angeles Cancino-Rodezno, Sarjeet S Gill, Mario Soberón, Alejandra Bravo
BACKGROUND: 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 disease vector has positioned its biological control as a primary health concern...
December 9, 2015: BMC Genomics
E O Juárez-Hernández, L E Casados-Vázquez, M C del Rincón-Castro, R Salcedo-Hernández, D K Bideshi, J E Barboza-Corona
AIMS: The objective of this study was to produce stable inclusions of chitinase ChiA74Δsp in Bacillus thuringiensis subsp. israelensis (Bti) and to assay its insecticidal activity against Aedes aegypti larvae. METHODS AND RESULTS: Bti was transformed with chiA74Δsp regulated by its own promoter or by the strong chimeric cytAp/STAB-SD promoter system to generate two recombinant Bti strains. These recombinants produced their native parasporal bodies composed of Cry4Aa, Cry4Ba, Cry11Aa and Cyt1Aa and ChiA74Δsp inclusions, and showed a approx...
December 2015: Journal of Applied Microbiology
S Balakrishnan, K Indira, M Srinivasan
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 bacterium and its efficacy was against the larval and pupal stages of two different species of mosquitoes and determined in terms of LC50 and LC90...
September 2015: Journal of Parasitic Diseases: Official Organ of the Indian Society for Parasitology
James F Harwood, Muhammad Farooq, Brent T Turnwall, Alec G Richardson
The principal vectors of chikungunya and dengue viruses typically oviposit in water-filled artificial and natural containers, including tree holes. Despite the risk these and similar tree hole-inhabiting mosquitoes present to global public health, surprisingly few studies have been conducted to determine an efficient method of applying larvicides specifically to tree holes. The Stihl SR 450, a backpack sprayer commonly utilized during military and civilian vector control operations, may be suitable for controlling larval tree-hole mosquitoes, as it is capable of delivering broadcast applications of granular and liquid dispersible formulations of Bacillus thuringiensis var...
July 2015: Journal of Medical Entomology
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