RESUMO
The yellow fever mosquito Aedes aegypti is an obligatory blood feeder and a major arboviral disease vector, evoking severe public health concerns worldwide. In adult female mosquitoes, the gut is critical for blood digestion and pathogen entry. We aimed for a systematic exploration of microRNA expression dynamics in the gut during the gonadotrophic cycle. Small RNA libraries were constructed from female mosquito gut tissues at five time points. Unsupervised hierarchical clustering revealed three expression clusters (early, mid and late) peaking at sequential time points - 24, 48 and 72 h posteclosion. Differentially expressed miRNAs were identified at 24 h post-blood meal (PBM). Depletions of Methoprene-tolerant [Met; the juvenile hormone (JH) receptor] and Ecdysone receptor [EcR; the receptor to 20-hydroxyecdysone (20E)] were performed using dsRNA to these genes to investigate impacts on microRNA expressions. Our results suggest that Met-mediated signalling downregulates miRNA expression from the early cluster and upregulates that from the late cluster. EcR signalling either up- or downregulated miRNA levels at 24 h PBM, indicating a differential effect of this receptor in miRNA gene expression. Furthermore, miR-281, which is the most abundant miRNA in the gut tissue, is induced and repressed by Met- and EcR-mediated signalling, respectively. Systematic depletion using synthetic antagomir and phenotype examinations indicate that miR-281 is obligatory for the normal progression of blood digestion, ovarian development and reproduction. Collectively, this study unveils expression dynamics of microRNAs in the female gut tissue during the gonadotrophic cycle and demonstrates that they are affected by JH and 20E signalling.
Assuntos
Galinhas/metabolismo , Trato Gastrointestinal/metabolismo , Regulação da Expressão Gênica/efeitos dos fármacos , Proteínas de Insetos/metabolismo , Hormônios Juvenis/farmacologia , MicroRNAs/metabolismo , Febre Amarela/genética , Aedes/fisiologia , Animais , Galinhas/parasitologia , Feminino , Trato Gastrointestinal/efeitos dos fármacos , Trato Gastrointestinal/parasitologia , Proteínas de Insetos/genética , MicroRNAs/genética , Mosquitos Vetores , Febre Amarela/parasitologiaRESUMO
In the 19th century, yellow fever thrived in the tropical, urban trade centers along the American Gulf Coast. Industrializing and populated, New Orleans and Memphis made excellent habitats for the yellow fever-carrying Aedes aegypti mosquitoes and the virulence they imparted on their victims. Known for its jaundice and black, blood-filled vomit, the malady terrorized the region for decades, sometimes claiming tens of thousands of lives during the near annual summertime outbreaks. In response to the failing medical community, a small, pronounced population of sick and healthy laypeople openly criticized the efforts to rid the Gulf region of yellow jack. Utilizing newspapers and cartoons to vocalize their opinions, these critics doubted and mocked the medical community, contributing to the regional and seasonal dilemma yellow fever posed for the American South. These sentient expressions prove to be an early example of patient distrust toward caregivers, a current problem in clinical heath care.
Assuntos
Aedes/fisiologia , Insetos Vetores/fisiologia , Opinião Pública/história , Febre Amarela/parasitologia , Aedes/virologia , Animais , Surtos de Doenças/história , História do Século XIX , Interações Hospedeiro-Patógeno , Humanos , Infectologia/história , Insetos Vetores/virologia , Nova Orleans/epidemiologia , Avaliação de Resultados em Cuidados de Saúde/história , Tennessee , Febre Amarela/epidemiologia , Febre Amarela/história , Vírus da Febre Amarela/fisiologiaRESUMO
Aedes aegypti developed a taste for humans at the birth of the Sahara, a new analysis suggests.
Assuntos
Aedes , Evolução Biológica , Mosquitos Vetores , Febre Amarela , Animais , Humanos , Aedes/fisiologia , Aedes/virologia , África do Norte , Febre Amarela/parasitologia , Febre Amarela/transmissão , Paladar , Mosquitos Vetores/fisiologia , Mosquitos Vetores/virologia , Mordeduras e Picadas/virologiaRESUMO
BACKGROUND: Mosquitoes are important pathogen vectors affecting human and other animals. Studies on genetic control of mosquito mediated disease transmission gained traction recently due to mosquito transgenesis technology. Active transposons are considered valuable tools to propagate pathogen resistance transgenes among mosquitoes, rendering the whole population recalcitrant to diseases. A major hurdle in this approach is the inefficient remobilization activity after the integration of heterologous transposon vectors bearing transgenes into chromosomes. Therefore, endogenous active transposons in mosquito genomes are highly desirable. RESULTS: Starting with the transposable element database of the yellow fever mosquito Aedes aegypti genome, detailed analyses of the members of each TE family were performed to identify sequences with multiple identical copies, an indicator of their latest or current transposition activity. Among a dozen of potentially active TE families, two DNA elements (TF000728 and TF000742 in TEfam) are short and nonautonomous. Close inspection of the elements revealed that these two families were previously mis-categorized and, unlike other known TEs, insert specifically at dinucleotide "AT". These two families were therefore designated as ATon-I and ATon-II. ATon-I has a total copy number of 294, among which three elements have more than 10 identical copies (146, 61 and 17). ATon-II has a total copy number of 317, among which three elements have more than 10 identical copies (84, 15 and 12). Genome wide searches revealed additional 24 ATon families in A. aegypti genome with nearly 6500 copies in total. Transposon display analysis of ATon-1 family using different A. aegypti strains suggests that the elements are similarly abundant in the tested mosquito strains. CONCLUSION: ATons are novel mobile genetic elements bearing terminal inverted repeats and insert specifically at dinucleotide "AT". Five ATon families contain elements existing at more than 10 identical copies, suggesting very recent or current transposition activity. A total of 24 new TE families with nearly 6000 copies were identified in this study.
Assuntos
Sequência Rica em At/genética , Aedes/genética , Elementos de DNA Transponíveis/genética , Febre Amarela/genética , Febre Amarela/parasitologia , Animais , Sequência de Bases , Feminino , Amplificação de Genes/genética , Genoma de Inseto/genética , Humanos , Sequências Repetidas Invertidas/genética , Masculino , Dados de Sequência MolecularRESUMO
While apoptosis regulation has been studied extensively in Drosophila melanogaster, similar studies in other insects, including disease vectors, lag far behind. In D. melanogaster, the inhibitor of apoptosis (IAP) protein DIAP1 is the major negative regulator of caspases, while IAP antagonists induce apoptosis, in part, by binding to DIAP1 and inhibiting its ability to regulate caspases. In this study, we characterized the roles of two IAP antagonists, Michelob_x (Mx) and IMP, in apoptosis in the yellow fever mosquito Aedes aegypti. Overexpression of Mx or IMP caused apoptosis in A. aegypti Aag2 cells, while silencing expression of mx or imp attenuated apoptosis. Addition of recombinant Mx or IMP, but not cytochrome c, to Aag2 cytosolic extract caused caspase activation. Consistent with this finding, AeIAP1 bound and inhibited both initiator and effector caspases from A. aegypti, and Mx and IMP competed with caspases for binding to AeIAP1. However, a difference was observed in the BIR domains responsible for Dronc binding by AeIAP1 versus DIAP1. These findings demonstrate that the mechanisms by which IAP antagonists regulate apoptosis are largely conserved between A. aegypti and D. melanogaster, although subtle differences exist.
Assuntos
Aedes/citologia , Aedes/metabolismo , Apoptose , Proteínas Inibidoras de Apoptose/antagonistas & inibidores , Proteínas de Insetos/metabolismo , Transdução de Sinais , Febre Amarela/parasitologia , Aedes/efeitos dos fármacos , Aedes/enzimologia , Animais , Apoptose/efeitos dos fármacos , Inibidores de Caspase , Caspases/metabolismo , Extratos Celulares , Linhagem Celular , Citocromos c/metabolismo , Ativação Enzimática/efeitos dos fármacos , Inibidores Enzimáticos/farmacologia , Inativação Gênica/efeitos dos fármacos , Proteínas Inibidoras de Apoptose/metabolismo , Insetos Vetores/citologia , Insetos Vetores/efeitos dos fármacos , Insetos Vetores/enzimologia , Insetos Vetores/metabolismo , Ligação Proteica/efeitos dos fármacos , Transdução de Sinais/efeitos dos fármacos , Sindbis virus/efeitos dos fármacos , Sindbis virus/metabolismoRESUMO
Odours are crucial cues enabling female mosquitoes to orient to prospective hosts. However, their in-flight manoeuvres to host odours are virtually unknown. Here we analyzed in 3-D the video records of female Aedes aegypti mosquitoes flying in a wind tunnel in response to host odour plumes that differed in spatial structure and composition. Following a brief (~0.03 s) encounter with CO(2), mosquitoes surged upwind and, in the absence of further encounters, counterturned without displacing upwind. These patterns resemble moth responses to encounter and loss of a filament of pheromone. Moreover, CO(2) encounters induced a highly regular pattern of counterturning across the windline in the horizontal (crosswind) and vertical planes, causing the mosquito to transect repeatedly the area where CO(2) was previously detected. However, despite the rapid changes across all three axes following an encounter with CO(2), the angular velocities remained remarkably constant. This suggests that during these CO(2)-induced surges mosquitoes stabilize flight through sensors, such as the halteres and Johnston organs, sensitive to Coriolis forces. In contrast to the instantaneous responses of the mosquito CO(2), a brief encounter with a filament of human skin odour did not induce a consistent change in mosquito flight. These differential responses were reflected in further experiments with broad plumes. A broad homogeneous plume of skin odour induced rapid upwind flight and source finding, whereas a broad filamentous plume of skin odour lowered activation rates, kinetic responses and source finding compared with homogeneous plumes. Apparently, yellow fever mosquitoes need longer continuous exposure to complex skin-odour blends to induce activation and source finding.
Assuntos
Aedes/efeitos dos fármacos , Aedes/fisiologia , Dióxido de Carbono/farmacologia , Voo Animal/fisiologia , Odorantes/análise , Pele , Febre Amarela/parasitologia , Animais , Simulação por Computador , Força Coriolis , Feminino , Humanos , Fatores de Tempo , VentoRESUMO
Aedes aegypti mosquitoes are the primary vectors of numerous viruses that impact human health. As manipulation of reproduction has been proposed to suppress mosquito populations, elucidation of biological processes that enable males and females to successfully reproduce is necessary. One essential process is female sperm storage in specialized structures called spermathecae. Aedes aegypti females typically mate once, requiring them to maintain sperm viably to fertilize eggs they lay over their lifetime. Spermathecal gene products are required for Drosophila sperm storage and sperm viability, and a spermathecal-derived heme peroxidase is required for long-term Anopheles gambiae fertility. Products of the Ae. aegypti spermathecae, and their response to mating, are largely unknown. Further, although female blood-feeding is essential for anautogenous mosquito reproduction, the transcriptional response to blood-ingestion remains undefined in any reproductive tissue. We conducted an RNAseq analysis of spermathecae from unfed virgins, mated only, and mated and blood-fed females at 6, 24, and 72 h post-mating and identified significant differentially expressed genes in each group at each timepoint. A blood-meal following mating induced a greater transcriptional response in the spermathecae than mating alone. This study provides the first view of elicited mRNA changes in the spermathecae by a blood-meal in mated females.
Assuntos
Aedes/fisiologia , Sangue/parasitologia , Mosquitos Vetores/fisiologia , Espermatozoides/metabolismo , Animais , Comportamento Alimentar , Feminino , Masculino , Comportamento Sexual Animal , Transcriptoma , Febre Amarela/parasitologiaRESUMO
The landscape's structure can play a relevant role in epidemic patterns of arboviruses, influencing factors such as abundance, movement, and dispersal ability in arthropod vectors and vertebrate hosts, besides promoting alterations in the rate of potential infectious contacts between these organisms. In the Americas, yellow fever (YF) exhibits only the sylvatic cycle, in which the virus circulates in sylvatic areas among non-human primates, being transmitted by mosquitoes of the Haemagogus and Sabethes genera. In this study, we investigate some aspects of the landscape in relation to diversity and abundance of culicid species associated with YF transmission. Studies were performed in the Cantareira State Park, a remnant of the Atlantic Forest located in Greater Metropolitan São Paulo, Brazil, where the YF virus circulated recently with dozens of deaths in howler monkeys (Alouatta guariba), in addition to reported human cases. Mosquito collections were carried out monthly from February 2015 to April 2017. Mosquitoes were collected from three sites using battery-powered aspirator (12-volt battery), CDC, and Shannon traps for adults, and suction samplers and entomological spoons in breeding sites to collect immature forms. 703 mosquitoes belonging to 12 species of the Aedini and Sabethini tribes were collected. Aedes scapularis and Psorophora ferox exhibited higher abundance, while Haemagogus leucocelaenus, the main vector of YF in São Paulo state, showed lower abundance in all sampled areas. The site with longer edge between forest area and anthropic area presented more richness and abundance of YF vector species, while the site with larger forest cover area and shorter edges between forest and anthropic areas exhibited an inverse pattern. Statistically significant differences were observed between the composition of potential YF vector species among the investigated sites. Although Hg. leucocelaenus occurred in all sampled sites, the different patterns of distribution and abundance of other mosquitoes such as Aedes scapularis and Psorophora ferox suggest that these species may be involved in the transmission of sylvatic YF in the study area.
Assuntos
Culicidae/fisiologia , Mosquitos Vetores/fisiologia , Febre Amarela/epidemiologia , Vírus da Febre Amarela , Animais , Oceano Atlântico , Brasil/epidemiologia , Cidades , Culicidae/classificação , Culicidae/virologia , Entomologia , Florestas , Humanos , Mosquitos Vetores/classificação , Mosquitos Vetores/virologia , Febre Amarela/parasitologiaRESUMO
Aedes aegypti mosquitoes are the vector for transmission of Dengue, Zika and chikungunya viruses. These mosquitos feed exclusively on human hosts for a blood meal. Previous studies have established that Dengue virus infection of the mosquito results in increased expression of the odorant binding proteins 22 and 10 within the mosquito salivary gland and silencing of these genes dramatically reduces blood-feeding behaviors. Odorant binding proteins are implicated in modulating the chemosensory perception of external stimuli that regulate behaviors such as host location, feeding and reproduction. However, the role that AeOBP22 plays in the salivary gland is unclear. Here, as a first step to a more complete understanding of the function of AeOBP22, we present the complete backbone and side chain chemical shift assignments of the protein in the complex it forms with arachidonic acid. These assignments reveal that the protein consists of seven α-helices, and that the arachidonic acid is bound tightly to the protein. Comparison with the chemical shift assignments of the apo-form of the protein reveals that binding of the fatty acid is accompanied by a large conformational change in the C-terminal helix, which appears disordered in the absence of lipid. This NMR data provides the basis for determining the structure of AeOBP22 and understanding the nature of the conformational changes that occur upon ligand binding. This information will provide a path to discover novel compounds that can interfere with AeOBP22 function and impact blood feeding by this mosquito.
Assuntos
Aedes/química , Ácido Araquidônico/metabolismo , Ressonância Magnética Nuclear Biomolecular , Receptores Odorantes/química , Febre Amarela/parasitologia , Animais , Ligação Proteica , Conformação ProteicaRESUMO
Aedes aegypti is a model species in which the endogenous regulation of odor-mediated host seeking behavior has received some attention. Sugar feeding and host seeking in female A. aegypti are transiently inhibited following a blood meal. This inhibition is partially mediated by short neuropeptide F (sNPF). The paired antennal lobes (ALs), as the first processing centers for olfactory information, has been shown to play a significant role in the neuropeptidergic regulation of odor-mediated behaviors in insects. The expression of sNPF, along with other peptides in the ALs of A. aegypti, indicate parallel neuromodulatory systems that may affect olfactory processing. To identify neuropeptides involved in regulating the odor-mediated host seeking behavior in A. aegypti, we use a semi-quantitative neuropeptidomic analysis of single ALs to analyze changes in the levels of five individual neuropeptides in response to different feeding regimes. Our results show that the level of sNPF-2, allatostatin-A-5 (AstA-5) and neuropeptide-like precursor-1-5 (NPLP-1-5), but not of tachykinin-related-peptides and SIFamide (SIFa), in the AL of female mosquitoes, changes 24 h and 48 h post-blood meal, and are dependent on prior access to sugar. To assess the role of these neuropeptides in modulating host seeking behavior, when systemically injected individually, sNPF-2 and AstA-5 significantly reduced host seeking behavior. However, only the injection of the binary mixture of the two neuropeptides lead to a host seeking inhibition similar to that observed in blood fed females. We conclude that modulation of the odor mediated host seeking behavior of A. aegypti is likely regulated by a dual neuropeptidergic pathway acting in concert in the ALs.
Assuntos
Aedes/fisiologia , Antenas de Artrópodes/metabolismo , Comportamento Alimentar , Comportamento de Busca por Hospedeiro , Neuropeptídeos/metabolismo , Odorantes , Febre Amarela/parasitologia , Animais , Feminino , Injeções , Marcação por Isótopo , Masculino , Peso Molecular , Neuropeptídeos/administração & dosagem , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz , Açúcares/metabolismoRESUMO
Ribonucleotide reductase (RNR) catalyzes the formation of deoxyribonucleotides, a rate limiting step in DNA synthesis. Class I RNR is a tetramer that consists of two subunits, R1 and R2; enzymatic activity requires association of R1 with R2. The R2 subunit is of special interest because it dictates the interaction with R1 that is required for enzymatic activity expression, and it is expressed only during the S phase of the cell cycle. We previously sequenced an R2 cDNA clone from the yellow fever mosquito, Aedes aegypti. We found the message was upregulated by blood feeding. We now report the sequence of an R2 genomic clone. The gene consists of 4 introns and 5 exons. Both major and minor transcriptional start sites have been identified, and their use differs in sugar-fed versus blood-fed females. The gene contains putative cis-regulatory sites for E2F, Caudal (Cdx) and Dearolf (Dfd). The mosquito R2 gene contains iron-specific regulatory elements immediately upstream of the minimal promoter region. Binding of a factor to the distal putative Cdx site in the -400 region is altered by iron treatment of cells. Further, following blood feeding, R2 message is significantly induced in mosquito ovaries (tissues that are involved in oogenesis--a process requiring DNA synthesis).
Assuntos
Aedes/enzimologia , Regulação Enzimológica da Expressão Gênica/genética , Ribonucleotídeo Redutases/genética , Febre Amarela/parasitologia , Aedes/genética , Animais , Pegada de DNA , Primers do DNA/genética , Perfilação da Expressão Gênica , Dados de Sequência Molecular , Regiões Promotoras Genéticas/genética , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Elementos Reguladores de Transcrição/genética , Deleção de Sequência/genética , Sítio de Iniciação de TranscriçãoRESUMO
Although considerable progress has been made in the past years in management of mosquito borne diseases such as malaria, dengue, yellow fever and West Nile fever through research in biology and ecology of the vectors, these diseases are still major threats to human health. Therefore, more research is required for better management of the diseases. This investigation provides information on the composition, co-occurrence, association and affinity indices of mosquito larvae in Mazandaran Province, northern Iran. In a large scale field study, mosquito larvae were collected from 120 sentinel sites in 16 counties in Mazandaran Province, using standard 350 ml dipper. Sampling took place monthly from May to December 2014. Collected larvae were mounted on glass slides using de Faure's medium and were diagnosed using morphological characters. Totally, 19,840 larvae were collected including three genera and 16 species from 120 larval habitats, as follows: Anopheles claviger, Anopheles hyrcanus, Anopheles maculipennis s.l., Anopheles marteri, Anopheles plumbeus, Anopheles pseudopictus, Culex pipiens, Culex tritaeniorhynchus, Culex torrentium, Culex perexiguus, Culex territans, Culex mimeticus, Culex hortensis, Culiseta annulata, Culiseta longiareolata, and Culiseta morsitans. Predominant species were Cx. pipiens and An. maculipennis s.l. which show the highest co-occurrence. The pair of species An. hyrcanus/An. pseudopictus showed significant affinity and association. High co-occurrence of the predominant species Cx. pipiens and An. maculipennis s.l. in the study area is of considerable importance in terms of vector ecology. It was also revealed that An. pseudopictus/An. hyrcanus often occur sympatrically indicating their common habitat requirements. The information may be equally important when vector control measures are considered.
Assuntos
Anopheles , Culex , Dengue/parasitologia , Vetores de Doenças , Ecologia , Malária/parasitologia , Febre Amarela/parasitologia , Animais , Biodiversidade , Dengue/epidemiologia , Ecossistema , Humanos , Irã (Geográfico)/epidemiologia , Larva , Malária/epidemiologia , Febre do Nilo Ocidental/epidemiologia , Febre Amarela/epidemiologiaRESUMO
Immune responses differ between laboratory mice and humans. Chronic infection with viruses and parasites are common in humans, but are absent in laboratory mice, and thus represent potential contributors to inter-species differences in immunity. To test this, we sequentially infected laboratory mice with herpesviruses, influenza, and an intestinal helminth and compared their blood immune signatures to mock-infected mice before and after vaccination against yellow fever virus (YFV-17D). Sequential infection altered pre- and post-vaccination gene expression, cytokines, and antibodies in blood. Sequential pathogen exposure induced gene signatures that recapitulated those seen in blood from pet store-raised versus laboratory mice, and adult versus cord blood in humans. Therefore, basal and vaccine-induced murine immune responses are altered by infection with agents common outside of barrier facilities. This raises the possibility that we can improve mouse models of vaccination and immunity by selective microbial exposure of laboratory animals to mimic that of humans.
Assuntos
Helmintíase/imunologia , Infecções por Herpesviridae/imunologia , Herpesviridae/imunologia , Enteropatias Parasitárias/imunologia , Vacina contra Febre Amarela/imunologia , Febre Amarela/imunologia , Febre Amarela/prevenção & controle , Vírus da Febre Amarela/imunologia , Animais , Anticorpos/sangue , Anticorpos Antivirais/imunologia , Coinfecção/imunologia , Coinfecção/parasitologia , Coinfecção/virologia , Citocinas/sangue , Modelos Animais de Doenças , Sangue Fetal/imunologia , Expressão Gênica , Helmintíase/prevenção & controle , Helmintíase/virologia , Infecções por Herpesviridae/prevenção & controle , Humanos , Imunidade Inata , Imunoglobulina G/sangue , Influenza Humana/imunologia , Influenza Humana/prevenção & controle , Enteropatias Parasitárias/prevenção & controle , Enteropatias Parasitárias/virologia , Camundongos , Camundongos Endogâmicos C57BL , Infecções por Orthomyxoviridae/imunologia , Infecções por Orthomyxoviridae/parasitologia , Infecções por Orthomyxoviridae/prevenção & controle , Febre Amarela/parasitologia , Febre Amarela/virologia , Vacina contra Febre Amarela/farmacologiaRESUMO
Following reports of two autochthonous cases of sylvatic yellow fever in the State of São Paulo, Brazil, in 2000, entomological surveys were conducted with the objective of verifying the occurrence of vector species in forest environments close to or associated with riparian areas located in the western and northwestern regions of the State. Culicidae were captured in 39 sites distributed in four regions. Haemagogus leucocelaenus and Aedes albopictus were the most abundant species and were captured in all the regions studied. H. leucocelaenus was the most abundant species in the municipalities of Santa Albertina and Ouroeste, where the two cases of sylvatic yellow fever had been reported. Mosquitoes from the janthinomys/capricornii group were only found at eight sites in the São José do Rio Preto region, while Sabethes chloropterus was found at one site in Ribeirão Preto. H. leucocelaenus showed its capacity to adapt to a secondary and degraded environment. Our results indicate a wide receptive area for yellow fever transmission in the State of São Paulo, with particular emphasis on the possibility of H. leucocelaenus being involved in the maintenance of this sylvatic focus of the disease.
Assuntos
Culicidae/classificação , Ecossistema , Insetos Vetores/classificação , Febre Amarela/parasitologia , Animais , Brasil , HumanosRESUMO
A young Danish sailor died from yellow fever in Barbados in 1887. The Shipmaster's letter to the family with a description of the course of the disease, which has been preserved, is presented here together with a photo of the sailor and a painting of the Danish sailing-ship.
Assuntos
Febre Amarela/história , Barbados , Dinamarca , Evolução Fatal , História do Século XIX , Humanos , Militares , Febre Amarela/parasitologia , Febre Amarela/patologiaRESUMO
After taking vertebrate blood, female mosquitoes quickly shed excess water and ions while retaining and concentrating the mostly proteinaceous nutrients. Aquaporins (AQPs) are an evolutionary conserved family of membrane transporter proteins that regulate the flow of water and in some cases glycerol and other small molecules across cellular membranes. In a previous study, we found six putative AQP genes in the genome of the yellow fever mosquito, Ae. aegypti, and demonstrated the involvement of three of them in the blood meal-induced diuresis. Here we characterized AQP expression in different tissues before and after a blood meal, explored the substrate specificity of AQPs expressed in the Malpighian tubules and performed RNAi-mediated knockdown and tested for changes in mosquito desiccation resistance. We found that AQPs are generally down-regulated 24â hrs after a blood meal. Ae. aegypti AQP 1 strictly transports water, AQP 2 and 5 demonstrate limited solute transport, but primarily function as water transporters. AQP 4 is an aquaglyceroporin with multiple substrates. Knockdown of AQPs expressed in the MTs increased survival of Ae. aegypti under dry conditions. We conclude that Malpighian tubules of adult female yellow fever mosquitoes utilize three distinct AQPs and one aquaglyceroporin in their osmoregulatory functions.
Assuntos
Aedes/metabolismo , Aquagliceroporinas/metabolismo , Aquaporinas/metabolismo , Febre Amarela/parasitologia , Aedes/genética , Animais , Aquagliceroporinas/genética , Aquaporinas/genética , Bioensaio , Transporte Biológico , Permeabilidade da Membrana Celular , Dessecação , Perfilação da Expressão Gênica , Regulação da Expressão Gênica , Técnicas de Silenciamento de Genes , Proteínas de Insetos/genética , Proteínas de Insetos/metabolismo , Oócitos/metabolismo , Especificidade de Órgãos/genética , Interferência de RNA , Água/metabolismo , XenopusRESUMO
Because the potential urban yellow fever (YF) mosquito vectors Aedes aegypti and Ae. albopictus are at historical highs in Brazil, both in terms of density and geographical range, we assessed the risk of an urban YF epidemic in Brazil. We evaluated and confirmed in a laboratory setting the vector competence of Brazilian Ae. aegypti for a currently circulating strain of YF virus, and investigated the potential for Brazilian Ae. albopictus to transmit YF.
Assuntos
Aedes/virologia , Surtos de Doenças , Insetos Vetores/virologia , Febre Amarela/epidemiologia , Vírus da Febre Amarela/isolamento & purificação , Animais , Brasil/epidemiologia , Humanos , Medição de Risco , Febre Amarela/parasitologia , Febre Amarela/transmissãoRESUMO
A little modification was made on the classical Borel tube, used for rearing isolated females of mosquitoes. The first studies were realized with the main Yellow fever vector, Haemagogus janthinomys, in Brazil. The results are: a better survival, as far as 72 days, a greater number of eggs, up to 80, and a shorter trophogonic cycle of 7-8 days. So, one can imagine more easily further studies about the vertical transmission of the YF virus by this important neo-tropical mosquito.
Assuntos
Animais de Laboratório/crescimento & desenvolvimento , Culicidae/crescimento & desenvolvimento , Entomologia/métodos , Insetos Vetores/crescimento & desenvolvimento , Animais , Feminino , Febre Amarela/parasitologiaRESUMO
BACKGROUND: 1-Octen-3-ol (octenol) is a common attractant released by vertebrates which in combination with carbon dioxide (CO(2)) attracts hematophagous arthropods including mosquitoes. A receptor neuron contained within basiconic sensilla on the maxillary palps of adult mosquitoes responds selectively to 1-octen-3-ol. Recently, an odorant receptor (AaegOR8) known to occur on the maxillary palps was expressed in a heterologous system and demonstrated to be selectively sensitive to (R)-(-)-1-octen-3-ol, one of two enantiomeric forms. Lesser responses were elicited by stimulation with the (S)-enantiomer and various structural analogs. METHODOLOGY/PRINCIPAL FINDINGS: Here we characterize the specificity of the octenol receptor neuron in the yellow fever mosquito, Aedes aegypti (L.), in vivo using single cell recordings. The octenol neuron is exquisitely sensitive to (R)-(-)-1-octen-3-ol; comparable responses to (S)-(+)-1-octen-3-ol were elicited only at stimulus doses over 100× that required for the (R)-enantiomer. An intermediate response closer to that elicited by the (R)-(-)-enantiomer was elicited by racemic 1-octen-3-ol. Small structural changes in (R)-(-)-1-octen-3-ol resulted in large decreases in responses. Increases in spike activity were also elicited in the octenol neuron by 2-undecanone, a known repellent; other repellents (DEET, IR3535 and picaridin) were inactive. CONCLUSIONS/SIGNIFICANCE: The results of our electrophysiological studies of the octenol receptor neuron in vivo approximates results of a previous study of the octenol receptor (AaegOR8 with its obligate partner Aaeg\ORco) expressed heterologously in Xenopus oocytes. By comparison of our current results with those of the heterologous expression study, we conclude that specificity of the octenol receptor neuron can be explained largely by characteristics of the OR alone without other associated proteins present in vivo. Our findings show that repellents may have specific stimulatory effects on receptor neurons and support the notion of repellents as modulators of mosquito odorant receptor activity.
Assuntos
Culicidae/citologia , Neurônios/metabolismo , Octanóis/metabolismo , Receptores Odorantes/metabolismo , Febre Amarela/parasitologia , Animais , EletrofisiologiaRESUMO
BACKGROUND: The fat body is the main organ of intermediary metabolism in insects and the principal source of hemolymph proteins. As part of our ongoing efforts to understand mosquito fat body physiology and to identify novel targets for insect control, we have conducted a transcriptome analysis of the fat body of Aedes aegypti before and in response to blood feeding. RESULTS: We created two fat body non-normalized EST libraries, one from mosquito fat bodies non-blood fed (NBF) and another from mosquitoes 24 hrs post-blood meal (PBM). 454 pyrosequencing of the non-normalized libraries resulted in 204,578 useable reads from the NBF sample and 323,474 useable reads from the PBM sample. Alignment of reads to the existing reference Ae. aegypti transcript libraries for analysis of differential expression between NBF and PBM samples revealed 116,912 and 115,051 matches, respectively. De novo assembly of the reads from the NBF sample resulted in 15,456 contigs, and assembly of the reads from the PBM sample resulted in 15,010 contigs. Collectively, 123 novel transcripts were identified within these contigs. Prominently expressed transcripts in the NBF fat body library were represented by transcripts encoding ribosomal proteins. Thirty-five point four percent of all reads in the PBM library were represented by transcripts that encode yolk proteins. The most highly expressed were transcripts encoding members of the cathepsin b, vitellogenin, vitellogenic carboxypeptidase, and vitelline membrane protein families. CONCLUSION: The two fat body transcriptomes were considerably different from each other in terms of transcript expression in terms of abundances of transcripts and genes expressed. They reflect the physiological shift of the pre-feeding fat body from a resting state to vitellogenic gene expression after feeding.