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1.
Pestic Biochem Physiol ; 170: 104666, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32980073

RESUMO

Despite the substantial progress achieved in the characterization of cytochrome P450 (CYP) -based resistance mechanisms in mosquitoes, a number of questions remain unanswered. These include: (i) the regulation and physiology of resistance conferring CYPs; (ii) the actual contribution of CYPs in resistance alone or in combination with other detoxification partners or other resistance mechanisms; (iii) the association between overexpression levels and allelic variation, with the catalytic activity and the intensity of resistance and (iv) the true value of molecular diagnostics targeting CYP markers, for driving decision making in the frame of Insecticide Resistance Management applications. Furthermore, the translation of CYP - based insecticide resistance research in mosquitoes into practical applications, is being developed, but it is not fully exploited, as yet. Examples include the production of high throughput platforms for screening the liability (stability) or inhibition potential of novel insecticidal leads and synergists (add-ons), as well as the exploration of the negative cross resistance concept (i.e. detoxification of certain insecticides, but activation of others pro-insecticides). The goal of this review is to critically summarise the current knowledge and the gaps of the CYP-based metabolic insecticide resistance in Anopheles and Aedes mosquito vectors. The progress and limitations of the protein and the reverse/forward genetic approaches, the understanding and importance of molecular and physiological aspects, as well as the current and future exploitation routes of CYP research are discussed.


Assuntos
Aedes/efeitos dos fármacos , Aedes/genética , Anopheles/efeitos dos fármacos , Anopheles/genética , Inseticidas/farmacologia , Piretrinas , Animais , Sistema Enzimático do Citocromo P-450/genética , Resistência a Inseticidas/efeitos dos fármacos , Resistência a Inseticidas/genética , Mosquitos Vetores/genética
2.
PLoS One ; 15(9): e0230984, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32946446

RESUMO

Insecticide resistance genes are often associated with pleiotropic effects on various mosquito life-history traits. However, very little information is available on the impact of insecticide resistance on blood feeding process in mosquitoes. Here, using two recently detected DNA-based metabolic markers in the major malaria vector, An. funestus, we investigated how metabolic resistance genes could affect the blood meal intake. After allowing both the field F1 and lab F8 Anopheles funestus strains to feed on the human arm for 30 minutes, we assessed the association between key parameters of blood meal process including, probing time, feeding duration, blood feeding success, blood meal size, and markers of glutathione S-transferase (L119F-GSTe2) and cytochrome P450 (CYP6P9a_R)-mediated metabolic resistance. None of the parameters of blood meal process was associated with L119F-GSTe2 genotypes. By contrast, for CYP6P9a_R, homozygous resistant mosquitoes were significantly more able to blood-feed than homozygous susceptible (OR = 3.3; CI 95%: 1.4-7.7; P = 0.01) mosquitoes. Moreover, the volume of blood meal ingested by CYP6P9a-SS mosquitoes was lower than that of CYP6P9a-RS (P<0.004) and of CYP6P9a-RR (P<0.006). This suggests that CYP6P9a gene is inked with the feeding success and blood meal size of An. funestus. However, no correlation was found in the expression of CYP6P9a and that of genes encoding for salivary proteins involved in blood meal process. This study suggests that P450-based metabolic resistance may influence the blood feeding process of Anopheles funestus mosquito and consequently its ability to transmit malaria parasites.


Assuntos
Anopheles/metabolismo , Sistema Enzimático do Citocromo P-450/metabolismo , Glutationa Transferase/metabolismo , Proteínas de Insetos/metabolismo , Mosquitos Vetores/metabolismo , Animais , Anopheles/efeitos dos fármacos , Anopheles/genética , Anopheles/parasitologia , Sangue/metabolismo , Camarões , Sistema Enzimático do Citocromo P-450/genética , Comportamento Alimentar , Feminino , Glutationa Transferase/genética , Humanos , Proteínas de Insetos/genética , Resistência a Inseticidas/genética , Inseticidas/farmacologia , Malária/parasitologia , Malária/prevenção & controle , Malária/transmissão , Mosquitos Vetores/efeitos dos fármacos , Mosquitos Vetores/genética , Mosquitos Vetores/parasitologia , Plasmodium/patogenicidade , Piretrinas/farmacologia , Proteínas e Peptídeos Salivares/metabolismo
3.
PLoS Comput Biol ; 16(8): e1008121, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32797077

RESUMO

Vector control has been a key component in the fight against malaria for decades, and chemical insecticides are critical to the success of vector control programs worldwide. However, increasing resistance to insecticides threatens to undermine these efforts. Understanding the evolution and propagation of resistance is thus imperative to mitigating loss of intervention effectiveness. Additionally, accelerated research and development of new tools that can be deployed alongside existing vector control strategies is key to eradicating malaria in the near future. Methods such as gene drives that aim to genetically modify large mosquito populations in the wild to either render them refractory to malaria or impair their reproduction may prove invaluable tools. Mathematical models of gene flow in populations, which is the transfer of genetic information from one population to another through migration, can offer invaluable insight into the behavior and potential impact of gene drives as well as the spread of insecticide resistance in the wild. Here, we present the first multi-locus, agent-based model of vector genetics that accounts for mutations and a many-to-many mapping cardinality of genotypes to phenotypes to investigate gene flow, and the propagation of gene drives in Anopheline populations. This model is embedded within a large scale individual-based model of malaria transmission representative of a high burden, high transmission setting characteristic of the Sahel. Results are presented for the selection of insecticide-resistant vectors and the spread of resistance through repeated deployment of insecticide treated nets (ITNs), in addition to scenarios where gene drives act in concert with existing vector control tools such as ITNs. The roles of seasonality, spatial distribution of vector habitat and feed sites, and existing vector control in propagating alleles that confer phenotypic traits via gene drives that result in reduced transmission are explored. The ability to model a spectrum of vector species with different genotypes and phenotypes in the context of malaria transmission allows us to test deployment strategies for existing interventions that reduce the deleterious effects of resistance and allows exploration of the impact of new tools being proposed or developed.


Assuntos
Anopheles/genética , Tecnologia de Impulso Genético/métodos , Resistência a Inseticidas/genética , Malária , Mosquitos Vetores/genética , Animais , Aptidão Genética , Humanos , Malária/prevenção & controle , Malária/transmissão , Análise de Sistemas
4.
Science ; 369(6507): 1128-1132, 2020 08 28.
Artigo em Inglês | MEDLINE | ID: mdl-32855340

RESUMO

Hemocytes limit the capacity of mosquitoes to transmit human pathogens. Here we profile the transcriptomes of 8506 hemocytes of Anopheles gambiae and Aedes aegypti mosquito vectors. Our data reveal the functional diversity of hemocytes, with different subtypes of granulocytes expressing distinct and evolutionarily conserved subsets of effector genes. A previously unidentified cell type in An. gambiae, which we term "megacyte," is defined by a specific transmembrane protein marker (TM7318) and high expression of lipopolysaccharide-induced tumor necrosis factor-α transcription factor 3 (LL3). Knockdown experiments indicate that LL3 mediates hemocyte differentiation during immune priming. We identify and validate two main hemocyte lineages and find evidence of proliferating granulocyte populations. This atlas of medically relevant invertebrate immune cells at single-cell resolution identifies cellular events that underpin mosquito immunity to malaria infection.


Assuntos
Aedes/imunologia , Anopheles/imunologia , Hemócitos/imunologia , Imunidade Celular , Malária/transmissão , Mosquitos Vetores/imunologia , Aedes/genética , Animais , Anopheles/genética , Feminino , Perfilação da Expressão Gênica , Técnicas de Silenciamento de Genes , Granulócitos/imunologia , Hemócitos/metabolismo , Malária/imunologia , Malária/parasitologia , Camundongos , Mosquitos Vetores/genética , RNA-Seq , Análise de Célula Única
5.
Proc Natl Acad Sci U S A ; 117(37): 22805-22814, 2020 09 15.
Artigo em Inglês | MEDLINE | ID: mdl-32839345

RESUMO

A Cas9/guide RNA-based gene drive strain, AgNosCd-1, was developed to deliver antiparasite effector molecules to the malaria vector mosquito, Anopheles gambiae The drive system targets the cardinal gene ortholog producing a red-eye phenotype. Drive can achieve 98 to 100% in both sexes and full introduction was observed in small cage trials within 6 to 10 generations following a single release of gene-drive males. No genetic load resulting from the integrated transgenes impaired drive performance in the trials. Potential drive-resistant target-site alleles arise at a frequency <0.1, and five of the most prevalent polymorphisms in the guide RNA target site in collections of colonized and wild-derived African mosquitoes do not prevent cleavage in vitro by the Cas9/guide RNA complex. Only one predicted off-target site is cleavable in vitro, with negligible deletions observed in vivo. AgNosCd-1 meets key performance criteria of a target product profile and can be a valuable component of a field-ready strain for mosquito population modification to control malaria transmission.


Assuntos
Anopheles/genética , Tecnologia de Impulso Genético/métodos , Controle de Mosquitos/métodos , Alelos , Animais , Animais Geneticamente Modificados/genética , Sistemas CRISPR-Cas/genética , Genética Populacional/métodos , Sequenciamento de Nucleotídeos em Larga Escala/métodos , Malária/prevenção & controle , Mosquitos Vetores/genética , Fenótipo , Transgenes/genética
6.
PLoS One ; 15(8): e0236920, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32745085

RESUMO

BACKGROUND: Twenty-seven villages were selected in southwest Burkina Faso to implement new vector control strategies in addition to long lasting insecticidal nets (LLINs) through a Randomized Controlled Trial (RCT). We conducted entomological surveys in the villages during the dry cold season (January 2017), dry hot season (March 2017) and rainy season (June 2017) to describe malaria vectors bionomics, insecticide resistance and transmission prior to this trial. METHODS: We carried out hourly catches (from 17:00 to 09:00) inside and outside 4 houses in each village using the Human Landing Catch technique. Mosquitoes were identified using morphological taxonomic keys. Specimens belonging to the Anopheles gambiae complex and Anopheles funestus group were identified using molecular techniques as well as detection of Plasmodium falciparum infection and insecticide resistance target-site mutations. RESULTS: Eight Anopheles species were detected in the area. Anopheles funestus s.s was the main vector during the dry cold season. It was replaced by Anopheles coluzzii during the dry hot season whereas An. coluzzii and An. gambiae s.s. were the dominant species during the rainy season. Species composition of the Anopheles population varied significantly among seasons. All insecticide resistance mechanisms (kdr-w, kdr-e and ace-1 target site mutations) investigated were found in each members of the An. gambiae complex but at different frequencies. We observed early and late biting phenotypes in the main malaria vector species. Entomological inoculation rates were 2.61, 2.67 and 11.25 infected bites per human per month during dry cold season, dry hot season and rainy season, respectively. CONCLUSION: The entomological indicators of malaria transmission were high despite the universal coverage with LLINs. We detected early and late biting phenotypes in the main malaria vector species as well as physiological insecticide resistance mechanisms. These data will be used to evaluate the impact of complementary tools to LLINs in an upcoming RCT.


Assuntos
Anopheles , Resistência a Inseticidas/genética , Malária Falciparum/transmissão , Mosquitos Vetores/genética , Animais , Anopheles/classificação , Anopheles/genética , Anopheles/parasitologia , Burkina Faso/epidemiologia , Culex/classificação , Culex/genética , Culex/parasitologia , Culicidae/classificação , Culicidae/genética , Culicidae/parasitologia , Ecologia , Genótipo , Humanos , Malária Falciparum/prevenção & controle , Controle de Mosquitos/métodos , Controle de Mosquitos/organização & administração , Mosquitos Vetores/classificação , Mosquitos Vetores/parasitologia , Plasmodium falciparum/isolamento & purificação , Estações do Ano
7.
PLoS Negl Trop Dis ; 14(7): e0008385, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32614914

RESUMO

Anopheles sundaicus s.l. is an important malaria vector primarily found in coastal landscapes of western and central Indonesia. The species complex has a wide geographical distribution in South and Southeast Asia and exhibits ecological and behavioural variability over its range. Studies on understanding the distribution of different members in the complex and their bionomics related to malaria transmission might be important guiding more effective vector intervention strategies. Female An. sundaicus s.l. were collected from seven provinces, 12 locations in Indonesia representing Sumatra: North Sumatra, Bangka-Belitung, South Lampung, and Bengkulu; in Java: West Java; and the Lesser Sunda Islands: West Nusa Tenggara and East Nusa Tenggara provinces. Sequencing of ribosomal DNA ITS2 gene fragments and two mitochondrial DNA gene markers, COI and cytb, enabled molecular identification of morphologically indistinguishable members of the complex. Findings allowed inference on the distribution of the An. sundaicus s.l. present in Indonesia and further illustrate the phylogenetic relationships of An. epiroticus within the complex. A total of 370 An. sundaicus s.l specimens were analysed for the ITS2 fragment. The ITS2 sequence alignment revealed two consistent species-specific point mutations, a T>C transition at base 479 and a G>T transversion at base 538 that differentiated five haplotypes: TG, CG, TT, CT, and TY. The TG haplotype matched published An. epiroticus-indicative sequences from Thailand, Vietnam and peninsular Malaysia. The previously described insertion event (base 603) was observed in all identified specimens. Analysis of the COI and cytb genes revealed no consistent nucleotide variations that could definitively distinguish An. epiroticus from other members in the Sundaicus Complex. The findings indicate and support the existence of An. epiroticus in North Sumatra and Bangka-Belitung archipelago. Further studies are recommended to determine the full distributional extent of the Sundaicus complex in Indonesia and investigate the role of these species in malaria transmission.


Assuntos
Anopheles , Malária/transmissão , Mosquitos Vetores , Animais , Anopheles/genética , Citocromos b/genética , Demografia , Complexo IV da Cadeia de Transporte de Elétrons/genética , Feminino , Humanos , Indonésia , Filogenia
8.
PLoS Genet ; 16(6): e1008822, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-32497040

RESUMO

Insecticide resistance in malaria vectors threatens to reverse recent gains in malaria control. Deciphering patterns of gene flow and resistance evolution in malaria vectors is crucial to improving control strategies and preventing malaria resurgence. A genome-wide survey of Anopheles funestus genetic diversity Africa-wide revealed evidences of a major division between southern Africa and elsewhere, associated with different population histories. Three genomic regions exhibited strong signatures of selective sweeps, each spanning major resistance loci (CYP6P9a/b, GSTe2 and CYP9K1). However, a sharp regional contrast was observed between populations correlating with gene flow barriers. Signatures of complex molecular evolution of resistance were detected with evidence of copy number variation, transposon insertion and a gene conversion between CYP6P9a/b paralog genes. Temporal analyses of samples before and after bed net scale up suggest that these genomic changes are driven by this control intervention. Multiple independent selective sweeps at the same locus in different parts of Africa suggests that local evolution of resistance in malaria vectors may be a greater threat than trans-regional spread of resistance haplotypes.


Assuntos
Anopheles/genética , Evolução Molecular , Genoma de Inseto/genética , Resistência a Inseticidas/genética , Malária/prevenção & controle , Mosquitos Vetores/genética , África , Alelos , Animais , Anopheles/parasitologia , Família 6 do Citocromo P450/genética , Variações do Número de Cópias de DNA , Elementos de DNA Transponíveis/genética , Fluxo Gênico , Loci Gênicos , Haplótipos , Humanos , Proteínas de Insetos/genética , Malária/parasitologia , Malária/transmissão , Metagenômica , Controle de Mosquitos/métodos , Polimorfismo Genético , Piretrinas , Sequenciamento Completo do Genoma
9.
Nat Biotechnol ; 38(9): 1054-1060, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32393821

RESUMO

Only female insects transmit diseases such as malaria, dengue and Zika; therefore, control methods that bias the sex ratio of insect offspring have long been sought. Genetic elements such as sex-chromosome drives can distort sex ratios to produce unisex populations that eventually collapse, but the underlying molecular mechanisms are unknown. We report a male-biased sex-distorter gene drive (SDGD) in the human malaria vector Anopheles gambiae. We induced super-Mendelian inheritance of the X-chromosome-shredding I-PpoI nuclease by coupling this to a CRISPR-based gene drive inserted into a conserved sequence of the doublesex (dsx) gene. In modeling of invasion dynamics, SDGD was predicted to have a quicker impact on female mosquito populations than previously developed gene drives targeting female fertility. The SDGD at the dsx locus led to a male-only population from a 2.5% starting allelic frequency in 10-14 generations, with population collapse and no selection for resistance. Our results support the use of SDGD for malaria vector control.


Assuntos
Anopheles/genética , Tecnologia de Impulso Genético/métodos , Malária/transmissão , Mosquitos Vetores/genética , Processos de Determinação Sexual/genética , Animais , Proteína 9 Associada à CRISPR/genética , Proteína 9 Associada à CRISPR/metabolismo , Sistemas CRISPR-Cas/genética , Endodesoxirribonucleases/genética , Endodesoxirribonucleases/metabolismo , Feminino , Proteínas de Insetos/genética , Proteínas de Insetos/metabolismo , Malária/prevenção & controle , Masculino , Controle de Mosquitos , Cromossomo X/genética , Cromossomo X/metabolismo
10.
Parasit Vectors ; 13(1): 202, 2020 Apr 19.
Artigo em Inglês | MEDLINE | ID: mdl-32307003

RESUMO

BACKGROUND: Malaria vector mosquitoes acquire midgut microbiota primarily from their habitat. The homeostasis of these microbial communities plays an essential role in the mosquito longevity, the most essential factor in the mosquito vectorial capacity. Our recent study revealed that silencing genes involved in regulation of the midgut homeostasis including FN3D1, FN3D3 and GPRGr9 reduced the survival of female adult Anopheles arabiensis mosquitoes. In the present study, we investigate the stability of the gene silencing efficiency of mosquitoes reared in three different breeding conditions representing distinct larval habitat types: town brick pits in Jimma, flood pools in the rural land of Asendabo and roadside pools in Wolkite. METHODS: First-instar larvae of An. arabiensis mosquitoes were reared separately using water collected from the three breeding sites. The resulting adult females were micro-injected with dsRNA targeting the FN3D1 gene (AARA003032) and their survival was monitored. Control mosquitoes were injected with dsRNA Lacz. In addition, the load of midgut microbiota of these mosquitoes was determined using flow cytometry. RESULTS: Survival of naïve adult female mosquitoes differed between the three sites. Mosquitoes reared using water collected from brick pits and flood pools survived longer than mosquitoes reared using water collected from roadside. However, the FN3D1 gene silencing effect on survival did not differ between the three sites. CONCLUSIONS: The present study revealed that the efficacy of FN3D1 gene silencing is not affected by variation in the larval habitat. Thus, silencing this gene has potential for application throughout sub-Saharan Africa.


Assuntos
Anopheles/genética , Domínio de Fibronectina Tipo III/genética , Interferência de RNA/fisiologia , Animais , Anopheles/fisiologia , Cruzamento , Ecossistema , Larva/genética , Larva/fisiologia , Controle de Mosquitos/métodos , Mosquitos Vetores/genética , Mosquitos Vetores/fisiologia
11.
PLoS Pathog ; 16(4): e1008453, 2020 04.
Artigo em Inglês | MEDLINE | ID: mdl-32330198

RESUMO

Malaria, caused by the protozoan parasite Plasmodium and transmitted by Anopheles mosquitoes, represents a major threat to human health. Plasmodium's infection cycle in the Anopheles vector is critical for transmission of the parasite between humans. The midgut-stage bottleneck of infection is largely imposed by the mosquito's innate immune system. microRNAs (miRNAs, small noncoding RNAs that bind to target RNAs to regulate gene expression) are also involved in regulating immunity and the anti-Plasmodium defense in mosquitoes. Here, we characterized the mosquito's miRNA responses to Plasmodium infection using an improved crosslinking and immunoprecipitation (CLIP) method, termed covalent ligation of endogenous Argonaute-bound RNAs (CLEAR)-CLIP. Three candidate miRNAs' influence on P. falciparum infection and midgut microbiota was studied through transgenically expressed miRNA sponges (miR-SPs) in midgut and fat body tissues. MiR-SPs mediated conditional depletion of aga-miR-14 or aga-miR-305, but not aga-miR-8, increased mosquito resistance to both P. falciparum and P. berghei infection, and enhanced the mosquitoes' antibacterial defenses. Transcriptome analysis revealed that depletion of aga-miR-14 or aga-miR-305 resulted in an increased expression of multiple immunity-related and anti-Plasmodium genes in mosquito midguts. The overall fitness cost of conditionally expressed miR-SPs was low, with only one of eight fitness parameters being adversely affected. Taken together, our results demonstrate that targeting mosquito miRNA by conditional expression of miR-SPs may have potential for the development of malaria control through genetically engineered mosquitoes.


Assuntos
Anopheles/imunologia , Malária Falciparum/parasitologia , MicroRNAs/imunologia , Mosquitos Vetores/imunologia , Plasmodium berghei/fisiologia , Plasmodium falciparum/fisiologia , Animais , Anopheles/genética , Anopheles/parasitologia , Feminino , MicroRNAs/genética , Mosquitos Vetores/genética , Mosquitos Vetores/parasitologia , Plasmodium berghei/genética , Plasmodium berghei/imunologia , Plasmodium falciparum/genética , Plasmodium falciparum/imunologia
12.
PLoS Genet ; 16(4): e1008765, 2020 04.
Artigo em Inglês | MEDLINE | ID: mdl-32339167

RESUMO

microRNAs (miRNAs) are increasingly recognized as important regulators of many biological processes in mosquitoes, vectors of numerous devastating infectious diseases. Identification of bona fide targets remains the bottleneck for functional studies of miRNAs. In this study, we used CLEAR-CLIP assays to systematically analyze miRNA-mRNA interactions in adult female Anopheles gambiae mosquitoes. Thousands of miRNA-target pairs were captured after direct ligation of the miRNA and its cognate target transcript in endogenous Argonaute-miRNA-mRNA complexes. Using two interactions detected in this manner, miR-309-SIX4 and let-7-kr-h1, we demonstrated the reliability of this experimental approach in identifying in vivo gene regulation by miRNAs. The miRNA-mRNA interaction dataset provided an invaluable opportunity to decipher targeting rules of mosquito miRNAs. Enriched motifs in the diverse targets of each miRNA indicated that the majority of mosquito miRNAs rely on seed-based canonical target recognition, while noncanonical miRNA binding sites are widespread and often contain motifs complementary to the central or 3' ends of miRNAs. The time-lapse study of miRNA-target interactomes in adult female mosquitoes revealed dynamic miRNA regulation of gene expression in response to varying nutritional sources and physiological demands. Interestingly, some miRNAs exhibited flexibility to use distinct sequences at different stages for target recognition. Furthermore, many miRNA-mRNA interactions displayed stage-specific patterns, especially for those genes involved in metabolism, suggesting that miRNAs play critical roles in precise control of gene expression to cope with enormous physiological demands associated with egg production. The global mapping of miRNA-target interactions contributes to our understanding of miRNA targeting specificity in non-model organisms. It also provides a roadmap for additional studies focused on regulatory functions of miRNAs in Anopheles gambiae.


Assuntos
Anopheles/genética , MicroRNAs/metabolismo , RNA Mensageiro/metabolismo , Animais , Anopheles/fisiologia , Proteínas Argonauta/genética , Proteínas Argonauta/metabolismo , Feminino , Proteínas de Insetos/genética , Proteínas de Insetos/metabolismo , Estágios do Ciclo de Vida , MicroRNAs/genética , RNA Mensageiro/genética , Reprodução
13.
Acta Trop ; 207: 105502, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32320680

RESUMO

Malaria is transmitted by Plasmodium parasites through the bite of female Anopheles mosquitoes. One of the most important mosquito vectors in the Greater Mekong Subregion is Anopheles dirus. This study reports RNA sequencing (RNA-Seq) transcriptome analysis of An. dirus at 18 hours and 7 days after a P. vivax-infected blood meal, which represent infection at the ookinete and oocyst parasite developmental stages, respectively. Following infection, 582 An. dirus transcripts were modulated. The 2,408 P. vivax transcripts could be classified into ookinete-specific, two-stage, and oocyst-specific groups. Results were validated by quantitative reverse transcription polymerase chain reaction. Gene ontology analysis of the vector and parasite revealed several biological pathways for both, providing a better understanding of Anopheles-Plasmodium interactions at the ookinete and oocyst stages.


Assuntos
Anopheles/genética , Perfilação da Expressão Gênica , Malária/transmissão , Mosquitos Vetores/genética , Plasmodium vivax/genética , Animais , Feminino , Oocistos/genética
14.
Acta Trop ; 207: 105494, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32330453

RESUMO

The Kingdom of Saudi Arabia (KSA) has a diverse fauna due to its peculiar position bordering the Afrotropical, Oriental and Palaearctic zoogeographic zones. The present study reports the phylogenetics of five mosquito species belonging to five series of Anopheles (Cellia) . We collected mosquito larvae from eastern, western and southwestern regions of KSA. The sampled mosquitoes were morphologically identified using the pictorial keys of mosquitoes and characterized by using single and multi-locus analysis of -internal transcribed spacer 2 (ITS2) region and cytochrome oxidase c subunit I (COI). Based on the morphological and molecular data, five species were recognized, like An. stephensi (Neocellia) (Oriental), An. arabiensis (Pyretophorus) (Afrotropical), An. dthali (Myzomyia) (Oriental and Palaearctic), An. cinereus (Paramyzomyia) and An. rhodesiensis rupicola (Neomyzomyia) (Oriental and Palaearctic). The phylogenetic analysis showed that An. stephensi is a monophyletic species with different ecotypes found in different geographic regions. Comprehensive phylogenetics and population genetics studies are crucial for a better understanding of the role of these five mosquito species in malarial transmission across various zoogeographic zones of different ecological and demographic characteristics.


Assuntos
Anopheles/classificação , Animais , Anopheles/genética , Malária/transmissão , Filogenia , Arábia Saudita
15.
Acta Trop ; 207: 105455, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32283092

RESUMO

This paper reports the results of a comparative molecular and morphological study of An. lindesayi collected from various districts of Bhutan and An. l. cameronensis from Thailand, compared with GenBank accessions and publications for An. l. japonicus from Japan, South Korea and China, An. l. pleccau from Taiwan, and An. lindesayi from India. Phylogenetic analyses based on ribosomal (ITS2) and mitochondrial (COI) DNA sequences using the Maximum Likelihood method revealed five genetically distinct clades (A, B, C, D and E) in Bhutan. Specimens in Clade A correspond to the original description of An. lindesayi, particularly in wing markings, the pattern of basal pale scales on the hindfemur and the single seta 4-C of larvae, and their COI sequences were closely related to one Indian sequence. Larvae of Clades B, C, D and E are similar in having seta 4-C branched rather than single. The adults of Clades C, D and E (B not available) are distinguishable from those of Clade A and other subspecies. Specimens of Clade C are unique in having a long pale spot on wing vein R and the subcosta, scattered pale scales on several veins and a dark spot at the tip of vein R2. The adults of Clades D and E are similar in having a dark spot at the tip of vein R2 and no scattered pale scales on all other veins. We provisionally recognize mosquitoes of Clades A, B, C, D and E as species A, B, C, D and E, respectively, of the Lindesayi Complex. Species A is An. lindesayi sensu stricto and the others are unnamed species. Concomitantly, the previous concept of the "Lindesayi Complex", which included An. lindesayi, An. menglangensis, An. nilgiricus and An. wellingtonianus, is now recognized as the Lindesayi Subgroup of the Lindesayi Group (Anopheles Series, subgenus Anopheles) with the five sibling species of An. lindesayi comprising a more apposite Lindesayi Complex within the subgroup.


Assuntos
Anopheles/anatomia & histologia , Anopheles/genética , Animais , Anopheles/classificação , Butão , Feminino , Masculino , Filogenia
16.
Biochim Biophys Acta Proteins Proteom ; 1868(6): 140413, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-32179182

RESUMO

Only recently it was discovered that haemoglobin (Hb) belongs to the standard gene repertoire of insects, although their tracheal system is used for respiration. A classical oxygen-carrying function of Hb is only obvious for hexapods living in hypoxic environments. In other insect species, including the common fruit fly Drosophila melanogaster, the physiological role of Hb is yet unclear. Here, we study recombinant haemoglobin from the European honeybee Apis mellifera (Ame) and the malaria mosquito Anopheles gambiae (Aga). Spectroscopic evidence shows that both proteins can be classified as hexacoordinate Hbs with a strong affinity for the distal histidine. AgaHb1 is proposed to play a role in oxygen transport or sensing based on its multimeric state, slow autoxidation, and small but significant amount of five-coordinated haem in the deoxy ferrous form. AmeHb appears to behave more like vertebrate neuroglobin with a complex function given its diversified distribution in the genome.


Assuntos
Anopheles/metabolismo , Abelhas/metabolismo , Hemoglobinas/análise , Sistema Respiratório/metabolismo , Análise Espectral/métodos , Animais , Anopheles/genética , Abelhas/genética , Drosophila melanogaster/genética , Drosophila melanogaster/metabolismo , Espectroscopia de Ressonância de Spin Eletrônica/métodos , Evolução Molecular , Compostos Férricos/química , Compostos Ferrosos/química , Genoma , Heme/metabolismo , Hemoglobinas/genética , Insetos/genética , Insetos/metabolismo , Ligantes , Espectroscopia de Ressonância Magnética , Espectrometria de Massas , Modelos Moleculares , Oxigênio
17.
Infect Dis Poverty ; 9(1): 30, 2020 Mar 18.
Artigo em Inglês | MEDLINE | ID: mdl-32183909

RESUMO

BACKGROUND: As of 2015 thousands of refugees are being hosted in temporary refugee camps in Greece. Displaced populations, travelling and living under poor conditions with limited access to healthcare are at a high risk of exposure to vector borne disease (VBD). This study sought to evaluate the risk for VBD transmission within refugee camps in Greece by analyzing the mosquito and sand fly populations present, in light of designing effective and efficient context specific vector and disease control programs. METHODS: A vector/pathogen surveillance network targeting mosquitoes and sand flies was deployed in four temporary refugee camps in Greece. Sample collections were conducted bi-weekly during June-September 2017 with the use of Centers for Disease Control (CDC) light traps and oviposition traps. Using conventional and molecular diagnostic tools we investigated the mosquito/sand fly species composition, population dynamics, pathogen infection rates, and insecticide resistance status in the major vector species. RESULTS: Important disease vectors including Anopheles sacharovi, Culex pipiens, Aedes albopictus and the Leishmania vectors Phlebotomus neglectus, P. perfiliewi and P. tobbi were recorded in the study refugee camps. No mosquito pathogens (Plasmodium parasites, flaviviruses) were detected in the analysed samples yet high sand fly Leishmania infection rates are reported. Culex pipiens mosquitoes displayed relatively high knock down resistance (kdr) mutation allelic frequencies (ranging from 41.0 to 63.3%) while kdr mutations were also detected in Ae. albopictus populations, but not in Anopheles and sand fly specimens. No diflubenzuron (DFB) mutations were detected in any of the mosquito species analysed. CONCLUSIONS: Important disease vectors and pathogens in vectors (Leishmania spp.) were recorded in the refugee camps indicating a situational risk factor for disease transmission. The Cx. pipiens and Ae. albopictus kdr mutation frequencies recorded pose a potential threat against the effectiveness of pyrethroid insecticides in these settings. In contrast, pyrethroids appear suitable for the control of Anopheles mosquitoes and sand flies and DFB for Cx. pipiens and Ae. albopictus larvicide applications. Targeted actions ensuring adequate living conditions and the establishment of integrated vector-borne disease surveillance programs in refugee settlements are essential for protecting refugee populations against VBDs.


Assuntos
Insetos Vetores/efeitos dos fármacos , Insetos Vetores/genética , Resistência a Inseticidas/genética , Leishmania , Controle de Mosquitos , Mosquitos Vetores/efeitos dos fármacos , Mosquitos Vetores/genética , Dinâmica Populacional , Campos de Refugiados , Aedes/efeitos dos fármacos , Aedes/genética , Animais , Anopheles/efeitos dos fármacos , Anopheles/genética , Culex/efeitos dos fármacos , Culex/genética , Feminino , Grécia , Leishmania/genética , Leishmania/patogenicidade , Leishmaniose/epidemiologia , Phlebotomus/efeitos dos fármacos , Phlebotomus/genética , Psychodidae
18.
Nat Commun ; 11(1): 1425, 2020 03 18.
Artigo em Inglês | MEDLINE | ID: mdl-32188851

RESUMO

A number of recent papers report that standing genetic variation in natural populations includes ubiquitous polymorphisms within target sites for Cas9-based gene drive (CGD) and that these "drive resistant alleles" (DRA) preclude the successful application of CGD for managing these populations. Here we report the results of a survey of 1280 genomes of the mosquitoes Anopheles gambiae, An. coluzzii, and Aedes aegypti in which we determine that ~90% of all protein-encoding CGD target genes in natural populations include at least one target site with no DRAs at a frequency of ≥1.0%. We conclude that the abundance of conserved target sites in mosquito genomes and the inherent flexibility in CGD design obviates the concern that DRAs present in the standing genetic variation of mosquito populations will be detrimental to the deployment of this technology for population modification strategies.


Assuntos
Aedes/genética , Anopheles/genética , Genoma de Inseto , Alelos , Animais , Sistemas CRISPR-Cas , Feminino , Frequência do Gene , Proteínas de Insetos/genética , Mosquitos Vetores/genética
19.
Acta Trop ; 206: 105440, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32156617

RESUMO

Despite reduction in the prevalence of malaria, Guinea-Bissau (GB) is still widely affected by the disease that is primarily vectored by Anopheles gambiae s.l. mosquitoes. Monitoring mosquito susceptibility and investigating the insecticide resistance status is an integral part of malaria control actions. Here, mosquito populations from five regions of GB: Bafatá, Bissau, Buba, Cacheu and Gabu were monitored for species ID and insecticide resistance, using diagnostic and intensity WHO bioassays, as well as molecular assays. Phenotypic and molecular identification of species showed the presence of An. gambiae s.s. (S form), An. coluzzii (M form) and An. arabiensis, as well as rare An. arabiensis/ An. gambiae hybrids. Resistance to permethrin and deltamethrin was found in all Anopheles populations assayed, with the intensity of resistance for permethrin being moderate to high, as confirmed by bioassays performed at concentration intensities of 5X and 10X. Consistent to these findings, molecular analysis showed a higher frequency of knock-down resistance (kdr) mutations (L1014F, L1014S, reaching > 90% in some areas) compared to previous studies in the same region, as well as detected for the first time the presence of the super kdr mutation (N1575Y) in GB. The "iAche" (G119S) resistance mutation was also found in GB in low frequencies (up to 12.41%). Additionally, the synergistic PBO-permethrin bioassays suggested partial involvement of non target (metabolic and/or reduced penetration) resistance mechanism. Expression analysis of known pyrethroid metabolisers indicated the slight overexpression and possible association of the cytochrome P450s CYP6Z1, CYP4G16 with the pyrethroid resistance phenotype. The findings should guide future evidence-based resistance management strategies in GB.


Assuntos
Anopheles/genética , Resistência a Inseticidas/genética , Malária/transmissão , Mosquitos Vetores/genética , Animais , Anopheles/efeitos dos fármacos , Feminino , Guiné-Bissau , Inseticidas/farmacologia , Masculino , Nitrilos/farmacologia , Permetrina/farmacologia , Piretrinas/farmacologia
20.
Parasit Vectors ; 13(1): 134, 2020 Mar 14.
Artigo em Inglês | MEDLINE | ID: mdl-32171326

RESUMO

BACKGROUND: Insecticide resistance is a growing concern for malaria control and vector control effectiveness relies on assessing it distribution and understanding its evolution. METHODS: We assessed resistance levels and the frequencies of two major target-site mutations, L1014F-VGSC and G119S-ace-1, conferring resistance to pyrethroids (PYRs) and carbamates/organophosphates (CXs/OPs) insecticides. These data were compared to those acquired between 2006 and 2010 to follow resistance evolutionary trends over ten years. RESULTS: We report the results of a 3-year survey (2013-2015) of insecticide resistance in 13 localities across the whole country of Benin. Permethrin (PYR) resistance was found in all populations tested, L1014F-VGSC being almost fixed everywhere, while bendiocarb resistance was limited to a few localities, G119S-ace-1 remaining rare, with very limited variations during surveyed period. Interestingly, we found no effect of the type of insecticide pressure on the dynamics of these mutations. CONCLUSIONS: These results confirm both the high prevalence of PYR resistance and the potential of CXs/OPs as short- to medium-term alternatives in Benin. They also underline the need for regular resistance monitoring and informed management in their usage, as the G119S-ace-1 mutation is already present in Benin and surrounding countries. Their unwise usage would rapidly lead to its spread, which would jeopardize PYR-resistant Anopheles control.


Assuntos
Alelos , Anopheles/efeitos dos fármacos , Anopheles/genética , Resistência a Múltiplos Medicamentos/genética , Resistência a Inseticidas/genética , Inseticidas/farmacologia , Animais , Benin , Carbamatos/farmacologia , Evolução Molecular , Feminino , Proteínas de Insetos/genética , Malária , Controle de Mosquitos/métodos , Mosquitos Vetores/efeitos dos fármacos , Mosquitos Vetores/genética , Mutação , Organofosfatos/farmacologia , Permetrina/farmacologia , Fenilcarbamatos , Piretrinas/farmacologia
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