Spatial mapping of gene expression in the salivary glands of the dengue vector mosquito, aedes aegypti

<p>Abstract</p> <p>Background</p> <p><it>Aedes aegypti </it>mosquitoes are the main vectors of dengue viruses to humans. Understanding their biology and interactions with the pathogen are prerequisites for development of dengue transmission control strategies. Mosquito salivary glands are organs involved directly in pathogen transmission to vertebrate hosts. Information on the spatial distribution of gene expression in these organs is expected to assist in the development of novel disease control strategies, including those that entail the release of transgenic mosquitoes with impaired vector competence.</p> <p>Results</p> <p>We report here the hybridization <it>in situ </it>patterns of 30 transcripts expressed in the salivary glands of adult <it>Ae. aegypti </it>females. Distinct spatial accumulation patterns were identified. The products of twelve genes are localized exclusively in the proximal-lateral lobes. Among these, three accumulate preferentially in the most anterior portion of the proximal-lateral lobe. This pattern revealed a salivary gland cell type previously undescribed in <it>Ae. aegypti</it>, which was validated by transmission electron microscopy. Five distinct gene products accumulate in the distal-lateral lobes and another five localize in the medial lobe. Seven transcripts are found in the distal-lateral and medial lobes. The transcriptional product of one gene accumulates in proximal- and distal-lateral lobes. Seven genes analyzed by quantitative PCR are expressed constitutively. The most abundant salivary gland transcripts are those localized within the proximal-lateral lobes, while previous work has shown that the distal-lateral lobes are the most active in protein synthesis. This incongruity suggests a role for translational regulation in mosquito saliva production.</p> <p>Conclusions</p> <p>Transgenic mosquitoes with reduced vector competence have been proposed as tools for the control of dengue virus transmission. Expression of anti-dengue effector molecules in the distal-lateral lobes of <it>Ae. aegypti </it>salivary glands has been shown to reduce prevalence and mean intensities of viral infection. We anticipate greater efficiency of viral suppression if effector genes are expressed in all lobes of the salivary glands. Based on our data, a minimum of two promoters is necessary to drive the expression of one or more anti-dengue genes in all cells of the female salivary glands.</p

Prevenção domiciliar da dengue: avaliação preliminar de tela protetora para pratos de vasos de planta

Avaliou-se em laboratório a eficácia de um protótipo de capa de tela de poliéster (evidengue®) destinada a vedar o acesso de fêmeas do mosquito Aedes aegypti a pratos de vasos de planta. Dois pratos de vasos com água foram envolvidos individualmente com a capa e colocados com os seus respectivos vasos em duas gaiolas entomológicas, um em cada gaiola. Numa terceira gaiola foi colocado um conjunto idêntico de prato e vasos sem a capa. Cada gaiola recebeu 20 fêmeas copuladas do mosquito, alimentadas com sangue de camundongo. Os resultados mostram que a capa foi eficaz como barreira ao acesso de fêmeas. Novos testes são necessários para se avaliar a eficácia da capa como dispositivo de prevenção da ovipostura nos pratos.The effectiveness of a polyester mesh cover (evidengue®), aimed at preventing the access of female Aedes aegypti mosquitoes to flowerpot saucers, was evaluated in laboratory. Two saucers of flowerpot with water were individually wrapped with the cover was placed with their respective pots in two entomological cages. One identical set of flowerpot and saucer was placed in a third cage. In each cage, 20 gravid females, fed on mouse blood, were released. Results show that the cover was effective to prevent access of females. Further tests are necessary to assess cover effectiveness as a device to prevent saucer oviposition.Se evaluó en laboratorio la eficiencia de una cubierta de tela de polyester (evidengue®) con el objetivo de vedar el acceso de hembras del mosquito Aedes aegypti a platos de macetas de planta. Fueron utilizadas tres jaulas entomológicas, dos de ellas con evidengue® y una para control. En cada jaula fueron colocados dos conjuntos de macetas de planta y platos y 20 hembras copuladas, alimentadas con sangre de ratón. Los resultados muestran que la cubierta fue eficaz como barrera al acceso de hembras. Nuevas pruebas son necesarias para evaluar la eficiencia de la cubierta como dispositivo de prevención de la oviposición en los platos

Do climate changes alter the distribution and transmission of malaria? Evidence assessment and recommendations for future studies

Malaria, a mosquito-borne infectious disease, is considered a significant global health burden. Climate changes or different weather conditions may impact infectious diseases, specifically those transmitted by insect vectors and contaminated water. Based on the current predictions for climate change associated with the increase in carbon dioxide concentrations in the atmosphere and the increase in atmospheric temperature, the Intergovernmental Panel on Climate Change predicts that in 2050, malaria may threaten some previously unexposed areas worldwide and cause a 50% higher probability of malaria cases. Climatebased distribution models of malaria depict an increase in the geographic distribution of the disease as global environmental temperatures and conditions worsen. Researchers have studied the influence of changes in climate on the prevalence of malaria using different mathematical models that consider different variables and predict the conditions for malaria distribution. In this context, we conducted a mini-review to elucidate the important aspects described in the literature on the influence of climate change in the distribution and transmission of malaria. It is important to develop possible risk management strategies and enhance the surveillance system enhanced even in currently malaria-free areas predicted to experience malaria in the future. © 2019, Sociedade Brasileira de Medicina Tropical. All rights reserved

Anopheles darlingi polytene chromosomes: Revised maps including newly described inversions and evidence for population structure in Manaus

Salivary gland polytene chromosomes of 4th instar Anopheles darlingi Root were examined from multiple locations in the Brazilian Amazon. Minor modifications were made to existing polytene photomaps. These included changes to the breakpoint positions of several previously described paracentric inversions and descriptions of four new paracentric inversions, two on the right arm of chromosome 3 and two on the left arm of chromosome 3 that were found in multiple locations. A total of 18 inversions on the X (n = 1) chromosome, chromosome 2 (n = 7) and 3 (n = 11) were scored for 83 individuals from Manaus, Macapá and Porto Velho municipalities. The frequency of 2Ra inversion karyotypes in Manaus shows significant deficiency of heterozygotes (p < 0.0009). No significant linkage disequilibrium was found between inversions on chromosome 2 and 3. We hypothesize that at least two sympatric subpopulations exist within the An. darlingi population at Manaus based on inversion frequencies. © Instituto Oswaldo Cruz - Fundação Oswaldo Cruz - Ministério da Saúde 2016

Vertical Transmission of Zika Virus (Flaviviridae, Flavivirus) in Amazonian Aedes aegypti (Diptera: Culicidae) delays egg hatching and larval development of progeny.

Zika virus (ZIKV) has emerged as a globally important arbovirus and has been reported from all states of Brazil. The virus is primarily transmitted to humans through the bite of an infective Aedes aegypti (Linnaeus, 1762) or Aedes albopictus (Skuse, 1895). However, it is important to know if ZIKV transmission also occurs from Ae. aegypti through infected eggs to her offspring. Therefore, a ZIKV and dengue virus (DENV) free colony was established from eggs collected in Manaus and maintained until the third?fourth generation in order to conduct ZIKV vertical transmission (VT) experiments which used an infectious bloodmeal as the route of virus exposure. The eggs from ZIKV-infected females were allowed to hatch. The resulting F1 progeny (larvae, pupae, and adults) were quantitative polymerase chain reaction (qPCR) assayed for ZIKV. The viability of ZIKV vertically transmitted to F1 progeny was evaluated by cultivation in C6/36 cells. The effects of ZIKV on immature development of Ae. aegypti was assessed and compared with noninfected mosquitoes. Amazonian Ae. Aegypti were highly susceptible to ZIKV infection (96.7%), and viable virus passed to their progeny via VT. Moreover, eggs from the ZIKV-infected mosquitoes had a significantly lower hatch rate and the slowest hatching. In addition, the larval development period was slower when compared to noninfected, control mosquitoes. This is the first study to illustrate VT initiated by oral infection of the parental population by using mosquitoes, which originated from the field and a ZIKV strain that is naturally circulating in-country. Additionally, this study suggests that ZIKV present in the Ae. aegypti can modify the mosquito life cycle. The data reported here suggest that VT of ZIKV to progeny from naturally infected females may have a critical epidemiological role in the dissemination and maintenance of the virus circulating in the vector

Metagenomics, paratransgenesis and the Anopheles microbiome: a portrait of the geographical distribution of the anopheline microbiota based on a meta-analysis of reported taxa

Anophelines harbour a diverse microbial consortium that may represent an extended gene pool for the host. The proposed effects of the insect microbiota span physiological, metabolic and immune processes. Here we synthesise how current metagenomic tools combined with classical culture-dependent techniques provide new insights in the elucidation of the role of the Anopheles-associated microbiota. Many proposed malaria control strategies have been based upon the immunomodulating effects that the bacterial components of the microbiota appear to exert and their ability to express anti-Plasmodium peptides. The number of identified bacterial taxa has increased in the current “omics” era and the available data are mostly scattered or in “tables” that are difficult to exploit. Published microbiota reports for multiple anopheline species were compiled in an Excel® spreadsheet. We then filtered the microbiota data using a continent-oriented criterion and generated a visual correlation showing the exclusive and shared bacterial genera among four continents. The data suggested the existence of a core group of bacteria associated in a stable manner with their anopheline hosts. However, the lack of data from Neotropical vectors may reduce the possibility of defining the core microbiota and understanding the mosquito-bacteria interactive consortium

Tipologia e distribuição de órgãos sensilares de Haematobia irritans adultas do Centro-Oeste do Brasil

Submitted by Nuzia Santos ([email protected]) on 2018-09-13T17:50:36Z No. of bitstreams: 1 Typology and distribution.pdf: 2416379 bytes, checksum: 296f31389232aedf8b8b329ff3cbb63a (MD5)Approved for entry into archive by Nuzia Santos ([email protected]) on 2018-09-13T18:01:00Z (GMT) No. of bitstreams: 1 Typology and distribution.pdf: 2416379 bytes, checksum: 296f31389232aedf8b8b329ff3cbb63a (MD5)Made available in DSpace on 2018-09-13T18:01:00Z (GMT). No. of bitstreams: 1 Typology and distribution.pdf: 2416379 bytes, checksum: 296f31389232aedf8b8b329ff3cbb63a (MD5) Previous issue date: 2018Universidade Federal de Goiás. Setor de Artropodologia Médica e Veterinária. Goiânia, GO, Brazil.Fundação Oswaldo Cruz. Instituto René Rachou. Laboratório de Entomologia Médica. Belo Horizonte, MG, Brazil.Considerando a grande importância econômica e sanitária de Haematobia irritans, o desenvolvimento de resistência desta espécie aos principais inseticidas químicos utilizados em seu controle, em diversas outras localidades do mundo, bem como que diferentes cepas de uma mesma espécie frequentemente apresentam diferentes tipos e padrões de distribuição sensilares, objetivou-se no presente trabalho investigar a tipologia e a distribuição dos diferentes tipos e subtipos sensilares de adulttos de H. irritans, oriunda de populações desta mosca presentes no centro-oeste brasileiro, com ênfase nas sensilas olfatórias. Este estudo apresenta novos dados sobre a tipologia e distribuição sensilar da antenna desta mosca. Em seus segmentos antenais foram observados pilosidades não enervadas e dez subtipos de sensilas, sendo: long bristles sensillum, long basiconic sensillum, blunt coeloconicsensillum, clavate coeloconic sensilla - single-tip and double-tip subtypes -, grooved coeloconic sensillum, long grooved coeloconic sensillum, trichoid sensillum, coeloconic sensillum, e smaller basiconic sensillum. Leve dimorfismo sexual foi observado em relação às sensilas antenais de H. irritans. Estes resultados fornecem uma base morfológica para futuras investigações sobre o comportamento mediado pelo olfato desta espécie, e poderão fomentar futuros estudos para desenvolvimento de medidas alternativas de monitoramento e controle de populações dessa mosca, com menor impacto.Considering the great economic and sanitarian importance of Haematobia irritans − the development of resistance of this species to the main chemical insecticides used in its control, in several other localities of the world; as well as that different strains of the same species frequently present different types and distribution patterns −, the present aim study was to investigate the typology and distribution of different types of sensillae of H. irritans adults, from populations of this fly present in Brazilian Midwest, with emphasis on olfactory sensillae. This study provides new data on the typology and sensillary distribution of antennal sensilla of this fly. In the antennal segments were found non-innervated spinules and ten subtypes of sensilla: long bristles sensillum, long basiconic sensillum, blunt coeloconic sensillum, clavate coeloconic sensilla − single-tip and double-tip subtypes −, grooved coeloconicsensillum, long grooved coeloconic sensillum, trichoid sensillum, coeloconic sensillum, and smaller basiconicsensillum. A slight sexual dimorphism was observed in the antennal sensillae of H. irritans. These results provide a morphological basis for future investigations on olfactory-mediated behavior of this species, and could assist future studies for the development of alternative measures to the monitoring and control of this fly populations, with less environmental impact

Typology and distribution of antennal sensory organs of adults Haematobia irritans of the Midwest Region of Brazil

ABSTRACT: Considering the great economic and sanitarian importance of Haematobia irritans − the development of resistance of this species to the main chemical insecticides used in its control, in several other localities of the world; as well as that different strains of the same species frequently present different types and distribution patterns −, the present aim study was to investigate the typology and distribution of different types of sensillae of H. irritans adults, from populations of this fly present in Brazilian Midwest, with emphasis on olfactory sensillae. This study provides new data on the typology and sensillary distribution of antennal sensilla of this fly. In the antennal segments were found non-innervated spinules and ten subtypes of sensilla: long bristles sensillum, long basiconic sensillum, blunt coeloconic sensillum, clavate coeloconic sensilla − single-tip and double-tip subtypes −, grooved coeloconic sensillum, long grooved coeloconic sensillum, trichoid sensillum, coeloconic sensillum, and smaller basiconic sensillum. A slight sexual dimorphism was observed in the antennal sensillae of H. irritans. These results provide a morphological basis for future investigations on olfactory-mediated behavior of this species, and could assist future studies for the development of alternative measures to the monitoring and control of this fly populations, with less environmental impact

Morphological features of the heart of six mosquito species as revealed by scanning electron microscopy

The circulatory system in insects is formed by a dorsal vessel (heart) that is a tubular structure that pumps haemolymph in the insect body cavity. Up until now, much is known about the structural organization of the heart in certain Brachycera (Diptera) (e.g. Drosophila). In contrast, little information is available regarding members of the Nematocera suborder (e.g. mosquitoes), in spite of their relevance to human health. Considering their importance, details of the heart morphology of six mosquito species (Aedes albopictus, Ae. aegypti, Ae. fluviatilis, Culex quinquefasciatus, Anopheles darlingi and An. aquasalis) were investigated by scanning electron microscopy (SEM). The heart of the adult mosquitoes, both males and females, consists of a dorsal tubular structure in association with pericardial cells located alongside the heart and alary muscles displaying ramifications that extend from the body wall to the heart surface. The SEM analysis also revealed in detail the organization of the heart, including paired valves on the heart wall (ostia). This study provides a detailed analysis of the mosquito heart microanatomy and, in our view, represents a significant contribution towards the understanding of structural– functional relationships associated with the heart of mosquito