Navegando por Autor "Pascini, Tales Vicari"
Agora exibindo 1 - 4 de 4
- Resultados por Página
- Opções de Ordenação
Item Aedes aegypti larvae treated with spinosad produce adults with damaged midgut and reduced fecundity(Chemosphere, 2019-04) Fernandes, Kenner Morais; Tomé, Hudson Vaner Ventura; Miranda, Franciane Rosa; Gonçalves, Wagner Gonzaga; Pascini, Tales Vicari; Serrão, José Eduardo; Martins, Gustavo Ferreirapt-BRThe mosquito Aedes aegypti is the main vector of Dengue, Chikungunya, Zika, and yellow fever viruses, which are responsible for high human morbidity and mortality. The fight against these pathogens is mainly based on the control of the insect vector with the use of insecticides. Among insecticides, spinosad bioinsecticide is efficient against A. aegypti larvae and may be an alternative for vector control. Here, we investigate the sublethal effects of spinosad during midgut metamorphosis of A. aegypti females and its cumulative effects on blood acquisition capacity and fecundity in adults. We studied the midgut because it is an important model organ directly related to blood acquisition and digestion. Treatment of larvae with spinosad induced oxidative stress, apoptosis, and damage to the midgut cells at all stages of development and in adults. There was a reduction in the number of proliferating cells and the number of enteroendocrine cells in treated individuals. In addition, damage caused by spinosad led to a reduction in oviposition and egg viability of A. aegypti females. Finally, the exposure of mosquito larvae to sublethal concentrations of spinosad interfered with the development of the midgut, arresting the blood digestion and reproduction of adult females with blood digestion and reproduction difficulties.Item Characterization of spermatheca-related genes in Aedes aegypti(Universidade Federal de Viçosa, 2018-07-27) Pascini, Tales Vicari; Martins, Gustavo Ferreira; http://lattes.cnpq.br/9264208382402040Aedes aegypti is an important hematophagous mosquito, with anthropophilic habits, also known as vector of important pathogens to humans, such as Yellow Fever, Dengue, Chikungunya, and, Zika viruses. A. aegypti females usually mate once, receiving the sperm to produce the whole offspring during their reproductive period. The spermatheca is responsible for sperm maintenance, nutrition and protection against physical and oxidative stress damage leading the long-term sperm storage process, resulting in the increase of the female fecundity. This reproductive autonomy of the females enhances their dispersion and then their vectorial capacity and the spermatheca play pivotal role providing the suitable environment, guaranteeing the sperm viability. There are three spermathecae in A. aegypti: two lateral and a central larger one. Considering the importance of this organ, in the present work, we reviewed different aspects of the spermatheca of insects, highlighting its importance for the reproductive success of the insects. This review also highlighted the number of spermathecae according to different taxonomic group, the role of different spermathecal parts (duct, reservoir, and gland), emphasizing their function along the processes of sperm maintenance. We also aimed to elucidate that the global gene expression in virgin and fertilized spermathecae (“spermathecomes”) separately, through RNA sequencing and bioinformatics analyzes. In virgin females, there is a greater number of coding sequences related to the establishment environment to receive and to allocate the spermatozoa. In fertilized spermathecae the most representative transcripts are related to the maintenance of the spermathecal microenvironment, thus prolonging the viability of these gametes. Differentially expressed genes (DEGs) were also analyzed by comparing virgin and fertilized spermathecae. We attempted the silencing of some of these DEG by the RNAi technique, to analyze the effects of knocking-down these genes throughout the reproductive process in A. aegypti. The females were injected with dsRNA of eight different genes related to energy metabolism (Ae-92048), chitin-bound components (Ae- 187521 and Ae-88956), transcriptional regulation (Ae-27176), hormonal regulation (AeSigP- 4002), enzymatic activity (Ae-SigP-212177), antimicrobial activity (AeSigP-109183) and ion homeostasis (AeSigP-66427). The gene silencing decreased the female survival, reduced the blood-feeding intake, nutrients storage/conversion, egg production and oviposition and offspring productions. In addition, the silencing of AeSigP-66427 affecting sperm motility and impaired egg production. At last, by the in situ hybridization we could detect in which part or the spermatheca, the chosen target genes are expressed. The present work is pioneer to identify the collection of genes expressed the virgin and fertilized spermathecae of A. aegypti. Through this intriguing study, we were able to elucidate the genes and some processes related to the long-term storage of spermatozoa in A. aegypti. Moreover, this work provided the basis for the establishment of alternative strategies to control this vector, by reducing its reproductive capacity.Item Desenvolvimento das espermatecas durante o estágio pupal de Aedes aegypti(Universidade Federal de Viçosa, 2014-07-25) Pascini, Tales Vicari; Martins, Gustavo Ferreira; http://buscatextual.cnpq.br/buscatextual/visualizacv.do?id=K4762374U1; http://lattes.cnpq.br/9264208382402040; Ortigão, José Marcelo Ramalho; http://lattes.cnpq.br/9599369401601455; Lino Neto, José; http://buscatextual.cnpq.br/buscatextual/visualizacv.do?id=K4786229P1As fêmeas dos culicídeos copulam uma única vez e são capazes de armazenar espermatozoides em um ou mais órgão(s) do sistema reprodutor denominado(s) espermateca(s). Em Aedes aegypti os espermatozoides são mantidos no interior de suas três espermatecas graças às secreções das glândulas espermatecais desse órgão. Apesar das espermatecas de A. aegypti serem bem caracterizadas, seu processo de desenvolvimento ainda é desconhecido. No presente trabalho estudamos o desenvolvimento das espermatecas ao longo da pupação, a partir do período de pupa branca até a fase adulta. Durante o desenvolvimento espermatecal não se observou alterações morfológicas como as descritas para Drosophila melanogaster, há somente um aumento de volume das células e crescimento de suas estruturas constituintes, possibilitando o rápido desenvolvimento desse órgão. No início da pupação (o estágio de pupa branca), a espermateca se apresenta como uma estrutura diminuta, que rapidamente cresce após 24 horas. Em 48 horas de pupação, se observa a glândula espermatecal, a deposição cuticular no reservatório e a presença de uma secreção com aspecto floculento, no lúmen do ducto espermatecal. Com 72 horas de pupação, observa-se novamente um aumento no volume do reservatório espermatecal, esse apresentando cutícula com todas as suas camadas formadas e o interior dos ductos das células glandulares repletos desse mesmo material floculento encontrado no período anterior. A presença desse material nos períodos iniciais de desenvolvimento parece promover a abertura do espaço onde vai ser formado o lúmen do ducto e do reservatório, que posteriormente vai sofrer o processo de deposição cuticular. Foram observadas algumas células em processo de morte celular. Há ainda, a presença de microvilosidades nas células epiteliais e nas células glandulares em todos os períodos analisados, que parece estar relacionada seja para a produção dos componentes para a formação da cutícula pelo epitélio ou no processo de secreção de substâncias lançadas no interior do lúmen do reservatório pela glândula espermatecal. Observou-se ainda, uma diferença temporal na estruturação entre o reservatório e o ducto espermatecal, que também foi observada em Tenebrio molitor e em D. melanogaster, o que pode ser pelo fato de o ducto espermatecal ser formado antes do reservatório. Já nas fêmeas recém- emergidas, a espermateca apresenta seu reservatório, glândula e ducto espermatecal completamente formados, com uma espessa camada cuticular e uma grande quantidade de material floculento e elétron-denso, que se acredita ser originado para fornecer as condições essenciais para a condução, alocação e manutenção da viabilidade dos espermatozoides em seu interior.Item Morphological and morphometrical assessment of spermathecae of Aedes aegypti females(Memórias do Instituto Oswaldo Cruz, 2012-03-27) Pascini, Tales Vicari; Ramalho-Ortigão, Marcelo; Martins, Gustavo FerreiraThe vectorial capacity of Aedes aegypti is directly influenced by its high reproductive output. Nevertheless, females are restricted to a single mating event, sufficient to acquire enough sperm to fertilize a lifetime supply of eggs. How Ae. aegypti is able to maintain viable spermatozoa remains a mystery. Male spermatozoa are stored within either of two spermathecae that in Ae. aegypti consist of one large and two smaller organs each. In addition, each organ is divided into reservoir, duct and glandular portions. Many aspects of the morphology of the spermatheca in virgin and inseminated Ae. aegypti were investigated here using a combination of light, confocal, electron and scanning microscopes, as well as histochemistry. The abundance of mitochondria and microvilli in spermathecal gland cells is suggestive of a secretory role and results obtained from periodic acid Schiff assays of cell apexes and lumens indicate that gland cells produce and secrete neutral polysaccharides probably related to maintenance of spermatozoa. These new data contribute to our understanding of gamete maintenance in the spermathecae of Ae. aegypti and to an improved general understanding of mosquito reproductive biology.