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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
41

Estudo das populações de Anofelinos em ambientes com diferentes graus de antropização no município do Cantá - Roraima

Christine de Souza Gomes, Elainne January 2005 (has links)
Made available in DSpace on 2014-06-12T15:07:30Z (GMT). No. of bitstreams: 2 arquivo9398_1.pdf: 723582 bytes, checksum: a74b99fbc6caba53d874185d4c81c04e (MD5) license.txt: 1748 bytes, checksum: 8a4605be74aa9ea9d79846c1fba20a33 (MD5) Previous issue date: 2005 / Embora a malária seja uma doença endêmica no Estado de Roraima, o registro das espécies de anofelinos que ocorrem na região ainda é escasso. Nesse estudo investigou-se a ocorrência, abundância e distribuição das espécies do gênero Anopheles, seus principais criadouros, a influência das estações seca e chuvosa sobre as populações desses mosquitos, bem como, a freqüência horária da sua atividade hematofágica. Duas áreas com diferentes graus de impactação antrópica foram escolhidas no município de Cantá. Cinco pontos fisionomicamente distintos, compreendendo: peridomicílio, intermediário, extradomicílio, borda de mata primária e curral, foram selecionados como locais de coleta nas áreas A e B. Os mosquitos foram capturados durante coletas de 4 horas (18-22h) e 12 horas (18-06h) por três e dois dias respectivamente, nos meses de fevereiro, maio, agosto e novembro de 2004. Um total de 3.279 espécimes foram capturadas, compreendendo 11 espécies de anofelinos: A. albitarsis (41,8%); A. darlingi (24,8%); A. triannulatus (17,6%); A. nuneztovari (11,8%); A. oswaldoi (1,5%); A. evansae (1,4%); A. argyritarsis, A. braziliensis, A. intermedius, A. mediopunctatus e A. peryassui representaram menos de 1% da amostra. A. albitarsis (55,5%) e A. darlingi (22,7%) predominaram na área mais antropizada (área A), enquanto A. triannulatus (34,6%) foi mais abundante na área mais preservada (área B). A maior densidade ocorreu em maio (período chuvoso), enquanto as menores, apresentaram-se em fevereiro e novembro (período de estiagem). Nos 21 criadouros encontrados, registrou-se nove espécies de anofelinos, duas das quais, A. minor e A. strodei, não foram capturadas como adultos. A atividade hematofágica dos anofelinos, durante as coletas de 12h, iniciou-se no primeiro horário de coleta (18-19h) nas duas localidades, sendo esse o horário de pico na área B. Na área A o pico ocorreu das 19-20h. A única espécie que manteve atividade durante toda a noite foi A. darlingi, com pico das 21-22 horas. Esses resultados mostraram uma grande diversidade de anofelinos na área estudada cuja abundância pode ser influenciada por ações antrópicas no ambiente e variações climáticas. Indicam também que A. albitarsis e A. darlingi apresentam maior atividade hematofágica no peridomicílio, favorecendo a transmissão do parasito da malária na região
42

Comparative Analysis of Heterochromatin in the Anopheles gambiae Complex

Sharma, Atashi 10 May 2016 (has links)
Mosquito borne diseases continue to be a big threat to human health worldwide. Despite using various vector control methods, we lose a great number of lives to this malicious disease in tropical and subtropical countries each year. Not surprisingly, mosquito is considered as the deadliest animal on the earth, because mortality rates from mosquito-vectored infections only lag behind other major diseases such as HIV and tuberculosis. Current approaches of vector control are mostly limited to using insecticidal bed nets, thus novel techniques are required to prevent a staggering loss to human health and quality of life. Advances in the genome sequencing in the past decade have helped to uncover numerous secrets of diverse genomes. The genome of malaria mosquito Anopheles gambiae was first sequenced in 2002 and since then has been updated to include additional scaffolds, their orientations and correction of mis-assemblies. Yet, the greatest challenge remains in assembling the heterochromatin regions, that are repeat rich part and contain relatively low-gene density. Although previously neglected by scientific studies due to its characteristic paucity of genes, heterochromatin is now recognized to be crucial for several processes such as cell viability, chromosome pairing, meiosis, longevity etc. It is therefore not surprising that heterochromatin comprises of a significant portion of the genome in many species. The efforts to analyze the genome of malaria mosquito in order to identify potential new leads for vector control warrant a better understanding of the heterochromatin. Mosquitoes diploid chromosome number equal 6. While autosomes 2 and 3 are submetacentric and present in both sexes, females are homogametic with XX and males are heterogametic with XY sex chromosomes. To achieve a better understanding of the Anopheles heterochromatin, we investigated heterochromatic region of the X chromosome. Despite one arm of the X chromosome being completely heterochromatic, few studies have investigated the molecular content of this region. Protocols were developed for performing fluorescent in situ hybridization (FISH) on mitotic X chromosomes in An. gambiae. Using cytogenetics and molecular biology techniques, we characterized the X chromosome heterochromatin in members of the An. gambiae complex. Specific satellite DNA and 18S ribosomal DNA probes (major components of heterochromatin) were mapped to X chromosomes enabling their differentiation and characterization in the An. gambiae complex. Microarray studies have highlighted the importance of X chromosome during investigation of nascent species An. gambiae and An. coluzzii. Here for the first time qualitative differences in heterochromatin in between nascent species are described. Cytogenetic idiograms are developed as to include the molecular and qualitative differences between the species of the An. gambiae complex. These idiograms are expected to provide a better resolution of the X chromosome heterochromatin for comparison in major malaria vectors, closing some of the gaps present due to poor sequencing of unassembled repeat rich regions in An. gambiae complex. The current understanding of Y chromosome for transgenic manipulation is poor and limited to very few genes. Due to its near total heterochromatic composition, it is the hardest part of the genome to assemble. In collaboration with other researchers, the Y chromosome content was characterized among sibling species of the An. gambiae complex. Our data revealed the swift changes the Y chromosome has undergone in a relatively short evolutionary time period. These include a rapid rate of turnover not only in heterochromatin but also in euchromatin. In addition to previously described repeats, a novel highly repetitive element called Zanzibar was discovered and mapped to the males of various Anopheles sibling species. Our data can form the basis for evolutionary studies in heterochromatin for male mosquitoes within the An. gambiae complex while also help identify novel targets to create successful transgenic male populations. Along with the X chromosome heterochromatin, to our knowledge this is the most extensive contribution to improve the understanding of mitotic chromosome heterochromatin in malaria mosquitoes. This study also investigated if epigenetics play role in mosquito development, fecundity and heterochromatin formation. DNA methylation, histone modifications and small noncoding RNAs are among the epigenetic mechanisms scrutinized in mammals. However, knowledge about epigenetic mechanisms and their effects is sparse in mosquitoes. A protocol for testing the various effects of epigenetics on different stages of malaria mosquito was developed. An epigenetic drug was utilized to probe the effects on immature and adult malaria mosquitoes. Different concentrations of DZNep, a histone methyltransferase inhibitor, were administered to An. coluzzii larvae. Total survivorship and pupation were compared for treated and untreated groups. The drug was also administered to adult blood feeding females to determine any effects on fecundity and egg morphology, revealing a negative association with an increase in drug concentration. A dose dependent decrease in SAH hydrolase concentration in An. coluzzii was also noticed. These results suggest epigenetics plays a critical role in mosquito pupation and ovarian development. Our work lays the groundwork for future investigations into the field of epigenetics in mosquitoes by revealing its effect on several important developmental stages in malaria mosquitoes. Although genomics and next-gen sequencing technology have come a long way in the last decade since the first Anopheles genome was sequenced, considerable gaps still exist in case characterization of heterochromatin function in an organism. Through our work, we have endeavored to elucidate a few of the major roles that heterochromatin may play in organization, evolution and adaptation of the malaria mosquitoes. / Ph. D.
43

Native plants as repellents against malaria mosquitoes : ethnobotanical, behavioural & electrophysiological studies /

Waka, Maedot. January 2005 (has links)
Diss. (sammanfattning). Uppsala : Sveriges lantbruksuniv. / Härtill 4 uppsatser.
44

Insecticide resistance in malaria vectors in central Sudan

Abdalla, Hiba Mohammed Abu Bakr 01 December 2008 (has links)
Malaria is the leading cause of mortality and morbidity in Sudan. The annual malaria cases and deaths are estimated at 7.5 million and 35, 000 respectively. One of the possible factors that have led to this situation is the development of insecticide resistance in the main malaria vector in Sudan, Anopheles arabiensis. This study therefore, was initiated to identify the malaria vectors in Gezira and Sennar states of central Sudan, determine their susceptibility levels to the different classes of insecticides used for malaria vector control, identify mechanisms of resistance, and determine the sporozoite infection rate and the blood meal sources in these populations. The polymerase chain reaction (PCR) for species identification revealed that An. arabiensis was the only member of the An. gambiae complex present in the study area. The blood meal analysis using ELISA showed high anthropophily with 89.2% feeding on humans. The overall sporozoite infection rate was 2.3 %. WHO susceptibility tests showed complete susceptibility of An. arabiensis to bendiocarb (100% mortality) and multiple resistance to permethrin (54-78%), DDT (55-66%) and malathion (76-78%). The kdr mutation analysis revealed the presence of the West African kdr allele with the majority of specimens being heterozygous (RS). The kdr in DDT/permethrin susceptible specimens were: 15% homozygous for the kdr mutation (RR), 64.2% heterozygous (RS) and 20.8% homozygous for the susceptible allele (SS). Amongst the DDT/permethrin resistant specimens, 13% were SS, 48.7% RS and 38.3% RR. The apparent lack of correlation between kdr and resistant phenotype strongly suggests that other resistance mechanisms are playing a role.
45

Insecticide resistance and Bionomics in laboratory reared and field caught Anopheles funestus Giles (Diptera: Culicidae)

Spillings, Belinda Lea 23 January 2013 (has links)
Malaria is transmitted by the mature, blood feeding portion of mosquito vector populations. Malaria vector control programs based on indoor residual spraying (IRS) of insecticides are designed to target resting adult Anopheles mosquitoes before or after they have blood fed. When a female mosquito acquires a blood meal, she could also ingest harmful xenobiotics that are present in the blood. During the resting period after feeding, many processes are initiated in order to assist in the digestion and assimilation of the blood. Ultimately, this enables the mosquito to absorb those amino acids needed for the biosynthesis of yolk proteins, which are essential for subsequent egg maturation. Since the regulation of xenobiotic (including insecticides) detoxification enzyme systems is likely to be altered in response to the ingestion of blood, this study aimed to investigate the effect of a blood meal on insecticide tolerance in insecticide resistant and susceptible southern African strains of the major malaria vector Anopheles funestus. Through the use of CDC bottle bioassays it was demonstrated that blood fed An. funestus carrying a pyrethroid resistant phenotype are even more tolerant of pyrethroid intoxication than their unfed counterparts. Using another major malaria vector, An. gambiae, microarray analysis revealed that a general increase in delta class glutathione-s-transferase (GST) expression occured in response to a blood meal. One gene, GSTD3, was over-expressed in both blood fed An. gambiae and An. funestus. Although this gene could not be validated with real time quantitative PCR, it serves as a viable target for future investigations. Since the pyrethroid resistant phenotype of southern African An. funestus has been linked to the over-expression of the duplicate copy gene CYP6P9, the expression levels of both copies of this gene were investigated. CYP6P9 and its copy, CYP6P13, showed a small but significant increase in expression in response to a blood meal. The increased expression of these major effect genes in response to blood feeding may be responsible for the increase in insecticide tolerance seen in the bottle bioassays. In an effort to repeat these experiments on wild caught An. funestus, field material was collected from Karonga in northern Malawi. Specimens were morphologically identified as members of the An. funestus group. However, attempts to molecularly identify them to species level failed. Through the use of ITS2 and D3 sequence analysis, cytogenetics and cross mating studies it was possible to conclude that these wild caught specimens were a new species. They have been provisionally named An. funestus-like.
46

The effects of pyrethroid resistance on transcription of metabolic enzymes in a major African Malaria vector, Anopheles funestus

Christian, Riann N 11 January 2012 (has links)
Anopheles funestus is a major vector of malaria in the southern African region. Insecticide resistance to pyrethroid and carbamate insecticides has been recorded in populations of this species in South Africa and Mozambique. This study aimed to determine the relationship between pyrethroid resistance and gene expression of two closely related genes, CYP6P9 and CYP6P13, by age and sex in a resistant strain An. funestus from southern Africa, FUMOZ-R. The insecticide susceptibility assays showed that percentage survival in both FUMOZ-R sexes significantly decreased as age increased. The mRNA expressions of CYP6P9 and CYP6P13 were higher in FUMOZ-R relative to the insecticide susceptible strain (FANG). The expression of permethrin resistance varies with age in An. funestus FUMOZ-R. The results indicate that other genes may also be involved in insecticide resistance. In addition to this, the expression profile of other metabolic genes involved in insecticide resistance was also investigated. A microarray based approach was used to identify genes differentially expressed in FUMOZ-R and FANG. As the full set of detoxification genes in An. funestus are unknown, this study investigated the utility of the An. gambiae detox chip to screen for differentially expressed detoxification genes in An. funestus. After optimization of the hybridisation conditions, over 90% of the probes showed a positive signal. Only three genes were significantly (P<0.001) differentially expressed in the females, CYP6P9, COI and CYP6M7. The same genes were also significantly differentially expressed in the adult males, together with an additional 21 transcripts. The third part of this study investigated the gene expression in the first instar, fourth instar and 3-day old adults in FUMOZ-R using the An. gambiae detox chip. The variation in metabolic enzyme gene transcription at the different developmental stages in An. funestus are not known. The identification of differentially transcribed genes at the different life stages provides some insight into the role and function of these genes. A large number of cytochrome P450s (monooxygenases), esterases, glutathione S-transferases (GSTs) and other additional genes were differentially expressed in all life stages. This study provided vital information regarding genes potentially involved in pyrethroid resistant and is the first to provide metabolic or detoxifying transcription gene information in An. funestus.
47

Biology of insecticide resistance in the African malaria vector Anopheles Funestus (Diptera: Culicidae)

Okoye, Patricia Nkem 15 October 2008 (has links)
The emergence of pyrethroid resistant Anopheles funestus (a major African vector) in malaria affected parts of KwaZuluNatal, South Africa was correlated with the malaria epidemic of 1996 2000. This finding prompted the necessity of incorporating insecticide resistance management strategies into formal malaria control policy in South Africa. Resistance management strategies often rely on the assumption of reduced fitness associated with insecticide resistance and are based on the principle that resistance genes will tend to drift out of vector populations in the absence of insecticide selection pressure. This study aimed to determine whether a fitness cost is associated with pyrethroid resistance as well as to determine the stability and mode of inheritance of the resistance genes in a pyrethroid resistant (FUMOZR) strain of An. funestus. It also aimed to sequence and analyze a segment of the sodium channel gene for any kdrtype mutation(s) that may be associated with pyrethroid resistance. The final aim was to determine the resistance mechanisms involved in a Ghanaian field population of An. funestus resistant to DDT and pyrethroids. Results obtained suggest that pyrethroid resistance in southern African An. funestus did not incur any loss of fitness. FUMOZR had a reproductive advantage over a pyrethroid susceptible An. funestus strain (FANG) in terms of higher fertility, proportion of females laying eggs and eggtoadult survivorship, and a lower sterility Click to buy NOW! PDFXCHANGE www.docutrack. com Click to buy NOW! PDFXCHANGE www.docutrack. com iv rate. However, FUMOZR had a slower developmental time from egg hatch to adult emergence than FANG. Results of crosses and backcrosses carried out between FUMOZR and FANG were consistent with a monofactorial and autosomal mode of inheritance in which the resistant genes presented as incompletely dominant. The resistant gene was found to be stable over several generations in the absence of insecticide selection pressure. Analysis of the genomic and mRNA sequences of the IIS5 IIS6 segment of the sodium channel gene showed a high sequence identity between FUMOZR and FANG suggesting that the two strains are genetically similar. The kdrtype mutation was absent from this region supporting previous evidence that the resistance mechanism is primarily metabolic. Bioassay data showed that a Ghanaian field population of An. funestus from Obuasi, Ghana, was resistant to DDT and pyrethroids. Molecular analysis of the IIS5 IIS6 segment of the sodium channel gene showed an absence of kdrtype mutations previously associated with insecticide resistance. Biochemical analysis suggests that resistance is metabolically mediated primarily by elevated levels of and esterases with monooxygenases and GSTs playing a lesser role. The presence of an altered acetylcholinesterase conferring carbamate resistance was also evident in the population. These results have implications for the management of resistance in malaria control programmes in Africa.
48

Anotação do transcriptoma parcial de Anopheles (Nyssorhynchus) darlingi Root, 1926

Azevedo Junior, Gilson Martins de 17 May 2011 (has links)
Submitted by Dominick Jesus (dominickdejesus@hotmail.com) on 2016-02-12T13:57:01Z No. of bitstreams: 2 Dissertação_Gilson Martins de Azevedo Junior.pdf: 1254971 bytes, checksum: 51958f6bacdcafd4834c3897c43f6193 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Made available in DSpace on 2016-02-12T13:57:01Z (GMT). No. of bitstreams: 2 Dissertação_Gilson Martins de Azevedo Junior.pdf: 1254971 bytes, checksum: 51958f6bacdcafd4834c3897c43f6193 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) Previous issue date: 2011-05-17 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / Disease-transmitting insects have been studied to characterize several biological and evolutionary aspects. Whole Genome sequencing has been allowing comparisons between the gene sequences of different species, providing molecular data. The mosquitoes Anopheles gambiae (subfamily Anophelinae), the most important vector of malaria in Africa, whose genome contains 278.253.050 base pairs (bp), Aedes aegypti, transmitter of Dengue, with 1.310.090.344 bp and Culex quinquefasciatus, vector of arbovirus, with 579.042.118 bp, both of (subfamily Culicinae) are cited. In Brazil, the Anopheles darlingi (subfamily Anophelinae) is the most important malaria vector, whose partial EST (Expressed Sequences Tags) libraries of adults and larvae previously obtained were analyzed in this study. Genic sequences of An. gambiae, Ae. aegypti and Cx. quinquefasciatus were analyzed for the presence of orthologous genes, in these mosquitoes in comparison with An. darling. An. darlingi’s ESTs (568 Unigenes) were virtually mapped in An. gambiae’s chromosomes. After that, differential gene expressions were analyzed, which allowed to statistically quantify the levels of differential expression of each gene, in the transcriptome of An. darlingi. The An. darlingi sequences were mapped according to onthologic terms of Gene Ontology (GO) and the sequences differentially expressed, with good statistical value that indicates the orthology were manually analyzed, according to the literature.The studies showed that 61% of An. darlingi are orthologous in An. gambiae and the in silico chromosomal mapping showed that the An. darling’s 568 Unigenes are represented in 793 chromosomal regions of An. gambiae, corroborating with evolutionary studies that say that the two species are evolutionarily close. An. darlingi sequences mapped in GO were associated with 1249 ontholgy levels and sublevels that describe a gene according to its function and cellular location. Differential expression analysis of some gene products was found more intense in larvae than in An. darlingi adults. Phylogenetic analysis of the An. darlingi glutathione-s-transferase (GST) gene was also done, an insecticide resistance gene which is well conserved, evolutionarily speaking, in An. gambiae, Ae. aegypti and Cx. quinquefasciatus. The Phylogenetic tree grouped An. darlingi and An. gambiae as sister species, because they are more evolutionarily related than Ae. aegypti and Cx. quinquefasciatus. In this analyses, the Phlebotomus papatasi was used as an external group, as the root of the tree. The manual annotation of An. darlingi ESTs sequences helped to understand the gene expression and evolutionary aspects of this mosquito related with An. gambiae, Ae. aegypti and Cx. quinquefasciatus, and also provided important data for further studies about individual genes of this malaria-transmitting species in Brazil. / Insetos transmissores de doenças têm sido estudados para caracterização de diversos aspectos biológicos e evolutivos. Sequenciamentos de genomas inteiros têm permitido comparações entre sequências gênicas de espécies diferentes, fornecendo dados moleculares. Citam-se os mosquitos Anopheles gambiae (subfamília Anophelinae), principal vetor da malária na África, cujo genoma contém 278.253.050 pares de bases (pb), o Aedes aegypti, transmissor do Dengue, com 1.310.090.344 pb e Culex quinquefasciatus, vetor de arboviroses, com 579.042.118 pb, ambos da (subfamília Culicinae). No Brasil, o Anopheles darlingi (subfamília Anophelinae) é o principal vetor da malária, cuja bibliotecas de ESTs (Expressed SequenceTags) parcial de adultos e larvas previamente obtidas foram analisadas no presente trabalho. Sequências gênicas de An. gambiae, Ae. aegypti e Cx. quinquefasciatus foram analisadas quanto a presença de genes em comum e genes ortólogos, nesses mosquitos em comparação com An. darlingi. ESTs (568 Unigenes) de An. darlingi foram mapeadas virtualmente em cromossômos de An. gambiae. Em seguida, foram realizadas análises de expressão diferencial gênica, o que permitiu quantificar estatisticamente os níveis de expressão de cada gene, no transcriptoma de An. darlingi. As sequências de An. darlingi foram mapeadas nos termos ontológicos do Gene Ontology (GO) e as sequências diferencialmente expressas, com bons valores estatísticos que indicam ortologia, foram analisadas manualmente, segundo a literatura. Os resultados mostraram que, 61% das sequências de An. darlingi são ortólogas em An. gambiae e o mapeamento cromossômico in silico mostrou que os 568 Unigenes de An. darlingi estão representados em 793 regiões cromossômicas do An. gambiae, corroborando estudos evolutivos de que as duas espécies são próximas evolutivamente. As sequências de An. darlingi analisadas no programa GO foram associadas a 1.249 níveis e subníveis de ontologias que descrevem um gene de acordo com sua função e localização celular. Análises de expressão diferencial de alguns produtos gênicos mostraram-se mais intensas em larvas do que em adultos de An. darlingi. Realizaram-se, ainda, a análise filogenética do gene da Glutationa-S-Transferase (GST) de An. darlingi, um gene de resistência a inseticidas bem conservado em termos evolutivos em An. gambiae, Ae. aegypti e Cx. quinquefasciatus. A árvore filogenética agrupou o gene da GST de An. darlingi com An. gambiae como espécies irmãs, estando estas proximamente relacionadas evolutivamente do que em relação ao Ae. aegypti e Cx. quinquefasciatus. O Phlebotomus papatasi, constou como grupo externo, para enraizamento dessa árvore. A anotação manual de ESTs de An. darlingi auxiliou na compreensão da expressão gênica e aspectos evolutivos desse mosquito em relação ao An. gambiae, Ae. aegypti e Cx. quinquefasciatus, além de fornecer dados importantes para estudos posteriores sobre funções gênicas individuais de An. darlingi transmissor da malária no Brasil.
49

Investigating the role of glutathione and glutathione biosynthetic genes in the adaptation of Anopheles gambiae to insecticides

Abdu, Habibu U. January 2015 (has links)
Malaria remains a serious public health challenge in the tropical world, with 584,000 deaths globally in 2013, of which 90% occurred in Africa, and mostly in pregnant women and children under the age of five. Anopheles gambiae (An. gambiae) is the principal malaria vector in Africa, where vector control measures involve the use of insecticides in the forms of long-lasting insecticide-treated nets (LLINs) and indoor residual spraying (IRS). The development of insecticides resistance mitigates these approaches. Glutathione (GSH) is widely distributed among all living organisms, and is associated with detoxification pathways, especially the Glutathione S-transferases (GSTs). Its direct involvement and relevance in insecticide resistance in An. gambiae has not been determined. Thus, this work examines the contribution of GSH, its biosynthetic genes (GCLM, GCLC) and their possible transcriptional regulator Nrf2 in insecticide resistance in An. gambiae sampled from agricultural setting (areas of intensive agriculture) and residential setting (domestic area). Bioinformatics analysis, W.H.O. adult susceptibility bioassays and molecular techniques were employed to investigate. Total RNA was first isolated from the adults An. gambiae mosquitoes raised from agricultural and residential field-caught larvae which had been either challenged or unchallenged with insecticides. Semi-quantitative RT-PCR using gel image densitometry was used to determine the expression levels of GCLM, GCLC genes and Nrf2. Bioinformatics’ results established the presence of putative AGAP010259 (AhR) and AGAP005300 (Nf2e1) transcription factor binding sites in An. gambiae GCLC and GCLM promoters in silico. An. gambiae s.l. studied here were highly resistant to DDT and permethrin but less resistant to bendiocarb. Both knockdown resistance (kdr) mutation variants L1014S and L1014F that confers resistance to pyrethroid insecticides were identified in both An. coluzzii and An. arabiensis sampled from northern Nigeria. The L1014F was much associated with An. coluzzii. A significant positive correlation (P=0.04) between the frequency of the L1014F point mutation and resistance to DDT and permethrin was observed. However, a weak or non-significant correlation (P=0.772) between the frequency of the L1014S point mutation and resistance was also found. L1014S and L1014F mutations co-occurred in both agricultural and residential settings with high frequencies. However, the frequencies of the two mutations were greater in the agricultural settings than in the residential settings. The levels of total, reduced and oxidized GSH were significantly higher in mosquitoes from agricultural sites than those from residential sites. Increased oxidized GSH levels appears to correlate with higher DDT resistance. The expression levels of GCLM, GCLC and Nrf2 were also significantly up-regulated in adults An. gambiae raised from agricultural and residential field-caught larvae when challenged with insecticide. However, there was higher constitutive expression of GCLM, GCLC and Nrf2 in mosquitoes from agricultural setting. The increased expression levels of these genes and also GSH levels in this population suggest their roles in the response and adaptation of An. gambiae to insecticide challenges. There exists the feasibility of using GSH status in An. gambiae to monitor adaptation and resistance to insecticides.
50

Caracterização funcional do sistema complemento e análise da microbiota de Anopheles darlingi em resposta à infecção com plasmodium vivax

Voges, Kamila January 2019 (has links)
Orientador: Jayme Augusto de Souza Neto / Resumo: A malária é uma doença ocasionada por protozoários do gênero Plasmodium e transmitida ao homem por meio da picada de mosquitos do gênero Anopheles. No Brasil a maior parte dos casos da doença concentra-se na região Amazônica, onde grande parte das infecções é causada por Plasmodium vivax, e o A. darlingi é o principal vetor. Estudos recentes indicam que a microbiota e que o sistema imune dos mosquitos do gênero Anopheles, em particular, componentes do sistema complemento, possuem uma importante função na determinação da competência vetorial, podendo modular o desenvolvimento do parasita no mosquito. Apesar da importância epidemiológica de A. darlingi, pouco se sabe a cerca da composição de sua microbiota intestinal, e sobre as interações moleculares deste vetor com P. vivax. Neste cenário, temos como principais objetivos: 1) Avaliar o papel de LRIM1 (Leucine-rich repeat protein 1), um dos genes do complemento, na interface A. darlingi-P.vivax, e 2) Averiguar determinados aspectos da interação entre microbiota- A.darlingi- P.vivax. Quanto às análises de LRIM1, as topologias das árvores filogenéticas mostram maior relação filogenética entre A. darlingi e A. albimanus, apresentando-os como táxons irmãos. Para a realização dos ensaios funcionais, sintetizamos RNA dupla-fita com base na sequência codificadora de LRIM1 de A. darlingi e microinjetamos no tórax de fêmeas desta espécie, as quais foram posteriormente submetidas a uma infecção por P. vivax. Quanto aos ensaios funcionais... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Malaria is a disease caused by protozoa of the genus Plasmodium and transmitted to humans through the bite of mosquitoes of the genus Anopheles. In Brazil, most cases of the disease are concentrated in the Amazon region, where most of the infections are caused by Plasmodium vivax, and A. darlingi is the main vector. Recent studies indicate that the microbiota and the immune system of Anopheles mosquitoes, in particular components of the complement system, play an important role in the determination of vector competence and can modulate the development of the parasite in the mosquito. Despite the epidemiological importance of A. darlingi, little is known about the composition of its intestinal microbiota, and about the molecular interactions of this vector with P. vivax. In this scenario, we have as main objectives: 1) To evaluate the role of LRIM1 (Leucine-rich repeat protein 1), one of the complement genes, in the interface A. darlingi-P.vivax, And 2) To ascertain some aspects of the interaction between microbiota- A.darlingi- P. vivax. As for the LRIM1 analyzes, the topologies of the phylogenetic trees show a higher phylogenetic relationship between A. darlingi and A. albimanus, presenting them as sister taxa. To perform the functional assays, we synthesized double-stranded RNA based on the coding sequence of A. darlingi LRIM1 and microinjections in the thorax of females of this species, which were subsequently subjected to a P. vivax infection. Regarding the functional tes... (Complete abstract click electronic access below) / Mestre

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