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Search Results: 1 - 10 of 24356 matches for " Anopheles gambiae M molecular form "
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Characterization of malaria transmission by vector populations for improved interventions during the dry season in the Kpone-on-Sea area of coastal Ghana
Tchouassi David P,Quakyi Isabella A,Addison Ebenezer A,Bosompem Kwabena M
Parasites & Vectors , 2012, DOI: 10.1186/1756-3305-5-212
Abstract: Background Malaria is a major public health problem in Ghana. We present a site-specific entomological study of malaria vectors and transmission indices as part of an effort to develop a site for the testing of improved control strategies including possible vaccine trials. Methods Pyrethrum spray catches (PSC), and indoor and outdoor human landing collections of adult female anopheline mosquitoes were carried out over a six-month period (November 2005 - April 2006) at Kpone-on-Sea, a fishing village in southern Ghana. These were morphologically identified to species level and sibling species of the Anopheles gambiae complex further characterized by the polymerase chain reaction (PCR). Enzyme-linked immunosorbent assay was used to detect Plasmodium falciparum mosquito infectivity and host blood meal sources. Parity rate was examined based on dilatation of ovarian tracheoles following dissection. Results Of the 1233 Anopheles mosquitoes collected, An. gambiae s.l. was predominant (99.5%), followed by An. funestus (0.4%) and An. pharoensis (0.1%). All An. gambiae s.l. examined (480) were identified as An. gambiae s.s. with a majority of M molecular form (98.2%) and only 1.8% S form with no record of M/S hybrid. A significantly higher proportion of anophelines were observed outdoors relative to indoors (χ2 = 159.34, df = 1, p < 0.0000). Only An. gambiae M molecular form contributed to transmission with a high degree of anthropophily, parity rate and an estimated entomological inoculation rate (EIR) of 62.1 infective bites/person/year. The Majority of the infective bites occurred outdoors after 09.00 pm reaching peaks between 12.00-01.00 am and 03.00-04.00 am. Conclusion Anopheles gambiae M molecular form is responsible for maintaining the status quo of malaria in the surveyed site during the study period. The findings provide a baseline for evidence-based planning and implementation of improved malaria interventions. The plasticity observed in biting patterns especially the combined outdoor and early biting behavior of the vector may undermine the success of insecticide-based strategies using insecticide treated nets (ITN) and indoor residual spray (IRS). As such, novel or improved vector interventions should be informed by the local malaria epidemiology data as it relates to vector behavior.
Differential Plasmodium falciparum infection of Anopheles gambiae s.s. molecular and chromosomal forms in Mali
Rebecca T Trout Fryxell, Catelyn C Nieman, Abdrahamane Fofana, Yoosook Lee, Sekou F Traoré, Anthony J Cornel, Shirley Luckhart, Gregory C Lanzaro
Malaria Journal , 2012, DOI: 10.1186/1475-2875-11-133
Abstract: Wild An. gambiae from two sites Kela (n?=?464) and Sidarebougou (n?=?266) in Mali were screened for the presence of P. falciparum CSP using an enzyme-linked immunosorbent assay (ELISA). Samples were then identified to molecular form using multiple PCR diagnostics (n?=?713) and chromosomal form using chromosomal karyotyping (n?=?419).Of 730 An. gambiae sensu lato (s.l.) mosquitoes, 89 (12.2%) were CSP ELISA positive. The percentage of positive mosquitoes varied by site: 52 (11.2%) in Kela and 37 (13.9%) in Sidarebougou. Eighty-seven of the positive mosquitoes were identified to molecular form and they consisted of nine Anopheles arabiensis (21.4%), 46?S (10.9%), 31?M (12.8%), and one MS hybrid (14.3%). Sixty of the positive mosquitoes were identified to chromosomal form and they consisted of five An. arabiensis (20.0%), 21 Savanna (15.1%), 21 Mopti (30.4%), 11 Bamako (9.2%), and two hybrids (20.0%).In this collection, the prevalence of P. falciparum infection in the M form was equivalent to infection in the S form (no molecular form differential infection). There was a significant differential infection by chromosomal form such that, P. falciparum infection was more prevalent in the Mopti chromosomal forms than in the Bamako or Savanna forms; the Mopti form was also the most underrepresented in the collection. Continued research on the differential P. falciparum infection of An. gambiae s.s. chromosomal and molecular forms may suggest that Plasmodium – An. gambiae interactions play a role in malaria transmission.
Molecular evolution of a gene cluster of serine proteases expressed in the Anopheles gambiae female reproductive tract
Emiliano Mancini, Federica Tammaro, Francesco Baldini, Allegra Via, Domenico Raimondo, Phillip George, Paolo Audisio, Igor V Sharakhov, Anna Tramontano, Flaminia Catteruccia, Alessandra della Torre
BMC Evolutionary Biology , 2011, DOI: 10.1186/1471-2148-11-72
Abstract: The analysis of polymorphisms and divergence of these female-expressed proteases in closely related species of the A. gambiae complex revealed a high level of replacement polymorphisms consistent with relaxed evolutionary constraints of duplicated genes, allowing to rapidly fix novel replacements to perform new or more specific functions. Adaptive evolution was detected in several codons of the 3 genes and hints of episodic selection were also found. In addition, the structural modelling of these proteases highlighted some important differences in their substrate specificity, and provided evidence that a number of sites evolving under selective pressures lie relatively close to the catalytic triad and/or on the edge of the specificity pocket, known to be involved in substrate recognition or binding. The observed patterns suggest that these proteases may interact with factors transferred by males during mating (e.g. substrates, inhibitors or pathogens) and that they may have differently evolved in independent A. gambiae lineages.Our results - also examined in light of constraints in the application of selection-inference methods to the closely related species of the A. gambiae complex - reveal an unexpectedly intricate evolutionary scenario. Further experimental analyses are needed to investigate the biological functions of these genes in order to better interpret their molecular evolution and to assess whether they represent possible targets for limiting the fertility of Anopheles mosquitoes in malaria vector control strategies.Sexual reproduction in organisms with internal fertilization is known to be mediated by a series of molecular interactions between the male ejaculate and female reproductive factors [1,2]. Since these interactions are fundamental to fertilization and, thus, for organismal fitness, molecular coevolution has been suggested to arise between male components and interacting female proteins [1,3,4]. While rapid evolution driven by positive selectio
Venugopal Gaddaguti, S Jwala Mounika, K Sowjanya, T Rao, MSR Krishna Chakravarthy R, Allu
International Journal of Bioassays , 2012,
Abstract: Plants constitute major source of drugs for prevention and spread of wide range of pathogenic carriers and also treating various diseases of human beings. Modern people increasingly prefer drugs of natural origin mostly from plant origin due to abundant accessibility and fewer side effects. Whereas synthetic drugs and antibiotics often cause wide spread toxicity and harmful side effects to the end user other than targeted health condition / pathogen carrier. In search of novel active compounds from plant origin, and to assess the efficient thereupatic properties with minimum side effects, application of advanced methods like GC MS and computational techniques play a crucial role in designing and development of drug of interest. 13 compounds were identified in aerial parts of Hyptis suaveolens L. methanolic extracts. Of the 13 compounds identified in the methonolic extract, Stigmast -5-en-3-ol, oleate, and Gamma-sitosterol and Butyl 11-eicosenoate found to represent 51.7% of the 13 compounds. Molecular docking studies were performed for all 13 compounds along with commercially known mosquito repellent compounds including DEET, Prallathrin, and Permithrin against Odorant Binding Protein (3N7H) of Anopheles gambiae using Schrodinger Maestro software. The binding affinities for compounds of Hyptis suaveolens were compared with known mosquito repellents for its ability to suppress human seeking behavior of mosquitoes and further possibility for designing of potential mosquito repellent natural compounds were discussed.
Dynamics of knockdown pyrethroid insecticide resistance alleles in a field population of Anopheles gambiae s.s. in southwestern Nigeria
T.S. Awolola, A.O. Oduola, I.O. Oyewole, J.B. Obansa, C.N. Amajoh
Journal of Vector Borne Diseases , 2007,
Abstract: Background & objectives: Pyrethroid insecticide resistance in the malaria vector Anopheles gambiaeGiles is mainly associated with reduced target site sensitivity arising from a single point mutation inthe sodium channel gene, often referred to as knockdown resistance (kdr). This resistance mechanismis widespread in West Africa and was reported for the first time in Nigeria in 2002. Here we presentchanges in the susceptibility/resistance status of the molecular ‘M’ and ‘S’ forms of An. gambiae andthe frequency of the kdr alleles from 2002–05.Methods: Adult anophelines were sampled quarterly inside human dwellings from January 2002 toDecember 2005 and adults reared from wild larvae were identified using morphological keys. Samplesbelonging to the An. gambiae complex were subjected to PCR assays for species identification anddetection of molecular ‘M’ and ‘S’ forms. Insecticide susceptibility tests were carried out usingstandard WHO procedures and test kits only on 2–3 days old adult An. gambiae s.s. reared fromlarval collections. The kdr genotypes were determined in both live and dead specimens of An. gambiaes.s. using alleles-specific polymerase chain reaction diagnostic tests.Results: The overall collection showed that the molecular ‘S’ form was predominant (>60%) but theproportions of both forms in the mosquito populations from 2002–05 were not statistically different.Both forms also occurred throughout the period without apparent relationship to wet or dry season.Insecticide susceptibility tests did not show any significant increase in the resistance status recordedfor either Permethrin or DDT from 2002–05, rather, an improvement in the susceptibility status ofthe mosquitoes to these insecticides was observed from 2004–05 relative to the tests performed in2002–03.Conclusion: The proportion of the molecular ‘M’ and ‘S’ form of An. gambiae and the kdr frequencieshave not increased significantly from 2002 when it was first reported in Nigeria. However, the findingson susceptible mosquitoes exhibiting the kdr gene need further investigation. Further monitoring ofthis may provide additional information on the ongoing debate on the possibility of restriction ingene flow and reproductive barriers in these sympatric taxa.
Tuti R. Hadi,Sustriayu Nalim
Bulletin of Health Research , 2012,
Abstract: An ecological survey was conducted in Central Sulawesi to obtain information on the distri-bution of reservoir hosts and vectors of arthropod-borne zoonotic diseases. Serological test were done from human sera collected in the area against arboviral and rickettsial antigens. Three species of Culex mosquitoes known as potential vectors of arbovirosis: Cx. bitaeni-orhynchus, Cx. gelidus and Cx. tritaeniorhynchus, were found in the area surveyed. A known vector of scrub typhus, Leptotrombidium (L.) deliensis, was also found in that area. Suspected reservoirs of arthropod-borne zoonosis in the area surveyed were chickens, ducks, cows, horses, monkeys and rats. The prevalence of antibodies against arbovirus group A antigens ( Chikungunya, Getah and Sindbis ) was 34,06%, 28,5% and 4,39%, against arbovirus group B antigen (Japanese Encepha-litis) was 93,4% and none against Rickettsia tsutsugamushi and Rickettsia typhy antigens, out of 91 human sera examined. Antibodies were found in animal sera examined against arbovirus group A and arbovirus group B antigens in a variation of 11,8% — 100%. The prevalence of antibodies against R. tsutsugamushi antigen was 22,7% out of 22 rat sera examined.
The molecular mechanism for DDT detoxification in Anopheles gambiae: A molecular docking study  [PDF]
William N. Setzer
Journal of Biophysical Chemistry (JBPC) , 2011, DOI: 10.4236/jbpc.2011.22016
Abstract: The epsilon class glutathione-S-transferase of Anopheles gambiae, agGSTe2, is capable of metabolizing DDT. A molecular docking analysis of DDT with agGSTe2 support an E2 elimination mechanism wherein the glutathione sulfur serves as the base to convert DDT to DDE.
Impact of Urban Agriculture on the Species Distribution and Insecticide Resistance Profile of Anopheles gambiae s.s. and Anopheles coluzzii in Accra Metropolis, Ghana  [PDF]
Joseph Chabi, Miracle C. Eziefule, Rebecca Pwalia, Joannitta Joannides, Dorothy Obuobi, Godwin Amlalo, Charlotte A. Addae, Iddrisu Alidu, Dominic Acquah-Baidoo, Samuel Akporh, Sampson Gbagba, Kwadwo K. Frempong, Melinda P. Hadi, Helen Pates Jamet, Samuel K. Dadzie
Advances in Entomology (AE) , 2018, DOI: 10.4236/ae.2018.63016
Abstract: Malaria incidence in urban areas has generally been low compared to rural areas but recent data indicate that urban malaria remains a public health problem. It is therefore important to understand the factors that promote urban malaria to help formulate future vector control strategies. This study compared Anopheles gambiae s.l. (A. gambiae s.l.) species composition, distribution and insecticide resistance mechanisms between vegetable and non-vegetable growing areas in Accra Metropolis. Four sites were selected within the city of Accra which comprised of two vegetable-growing and two non-vegetable growing areas. WHO susceptibility tests were carried out on adults A. gambiae s.l. reared from larvae collected from the sites. Five insecticides were tested and the A. gambiae complex, resistance genotypes and enzyme activities of each population were characterized. All A. gambiae s.l. populations tested were resistant to all the insecticides, but relatively lower mortalities were observed in the vegetable growing areas. The mortality against 0.05% deltamethrin was 2.6% (Opeibea) and 12.5% (Korle-Bu) for the vegetable growing areas and 36.2% (Achimota) and 38.9% (Mataheko) in the non-vegetable growing areas. Anopheles gambiae s.s. (95% of Opeibea population) and Anopheles coluzzii, (98% of Korle-Bu population) were the dominant species in the vegetable growing areas. The voltage-gated sodium channel (Vgsc-1014F) frequencies of all the populations were similar but the acetylcholinesterase (ace-1) frequencies were significantly lower (p < 0.05) in Korle-Bu and Mataheko populations. High level of P450s and esterases were observed in the A. gambiae s.l. from Opeibea than from the other areas. The contribution of urban agriculture in the development of insecticide resistance needs to be considered in the formulation of future vector control strategies alongside other domestic usages.
Fine-scale evolutionary genetic insights into Anopheles gambiae X-chromosome  [PDF]
Hemlata Srivastava, Jyotsana Dixit, Aditya P. Dash, Aparup Das
Journal of Biomedical Science and Engineering (JBiSE) , 2009, DOI: 10.4236/jbise.2009.25045
Abstract: Understanding the genetic architecture of indi-vidual taxa of medical importance is the first step for designing disease preventive strategies. To understand the genetic details and evolu-tionary perspective of the model malaria vector, Anopheles gambiae and to use the information in other species of local importance, we scanned the published X-chromosome se-quence for detail characterization and obtain evolutionary status of different genes. The te-locentric X-chromosome contains 106 genes of known functions and 982 novel genes. Majori-ties of both the known and novel genes are with introns. The known genes are strictly biased towards less number of introns; about half of the total known genes have only one or two in-trons. The extreme sized (either long or short) genes were found to be most prevalent (58% short and 23% large). Statistically significant positive correlations between gene length and intron length as well as with intron number and intron length were obtained signifying the role of introns in contributing to the overall size of the known genes of X-chromosome in An. gam-biae. We compared each individual gene of An. gambiae with 33 other taxa having whole ge-nome sequence information. In general, the mosquito Aedes aegypti was found to be ge-netically closest and the yeast Saccharomyces cerevisiae as most distant taxa to An. gambiae. Further, only about a quarter of the known genes of X-chromosome were unique to An. gambiae and majorities have orthologs in dif-ferent taxa. A phylogenetic tree was constructed based on a single gene found to be highly orthologous across all the 34 taxa. Evolutionary relationships among 13 different taxa were in-ferred which corroborate the previous and pre-sent findings on genetic relationships across various taxa.
Spatial distribution and male mating success of Anopheles gambiae swarms
Abdoulaye Diabaté, Alpha S Yaro, Adama Dao, Moussa Diallo, Diana L Huestis, Tovi Lehmann
BMC Evolutionary Biology , 2011, DOI: 10.1186/1471-2148-11-184
Abstract: We found substantial variation in swarm size and in mating success between swarms. A strong correlation between swarm size and mating success was observed, and consistent with the hotspot model of lek formation, the per capita mating success of individual males did not increase with swarm size. For the spatial distribution of swarms, our results revealed that some display sites were more attractive to both males and females and that females were more attracted to large swarms. While the swarm markers we recognize help us in localizing swarms, they did not account for the variation in swarm size or in the swarm mating success, suggesting that mosquitoes probably are attracted to these markers, but also perceive and respond to other aspects of the swarming site.Characterizing the mating system of a species helps understand how this species has evolved and how selective pressures operate on male and female traits. The current study looked at male mating success of An. gambiae and discussed possible factors that account for its variation. We found that swarms of An. gambiae conform to the hotspot model of lek formation. But because swarms may lack the female choice component, we propose that the An. gambiae mating system is a lek-like system that incorporates characteristics pertaining to other mating systems such as scramble mating competition.Lekking behaviour is a frequent and conspicuous type of mating aggregation where males gather and display to prospective mates [1], and references therein. Display territories do not hold resources attractive to females other than the males themselves, hence it is assumed that females visit leks solely to copulate [2]. Lekking mating systems are characterized by (i) male clustering; (ii) no male parental care; (iii) no resource on the territory; (iv) fighting over male territories; (v) females mate choice; and (vi) in many cases, stability of lek location over time [3], and references therein. Although the lek mating system has s
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