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Showing papers by "Gustavo Ferreira Martins published in 2019"


Journal ArticleDOI
04 Sep 2019-PeerJ
TL;DR: The pyriproxyfen causes remarkable histopathological and cytotoxic alterations in the midgut of larvae, and data suggest that pyri proxyfen can be used to help to control and eradicate this insect vector.
Abstract: Juvenile hormone analogs (JHA) are known to interfere with growth and biosynthesis of insects with potential for insecticide action. However, there has been comparatively few data on morphological effects of JHA on insect organs. To determine pyriproxyfen effects on Aedes aegypti larvae, we conducted toxicity, behavioral bioassays and assessed ultrastructural effects of pyriproxyfen on midgut cells. A. aegypti larvae were exposed in aqueous solution of pyriproxyfen LC50 concentrations and evaluated for 24 h. This study fulfilled the toxic prevalence of pyriproxyfen to A. aegypti larvae (LC50 = 8.2 mg L-1). Behavioral observations confirmed that pyriproxyfen treatment significantly changes swimming behavior of larvae, limiting its displacement and speed. The pyriproxyfen causes remarkable histopathological and cytotoxic alterations in the midgut of larvae. Histopathological study reveals presence of cytoplasmic vacuolization and damage to brush border of the digestive cells. The main salient lesions of cytotoxic effects are occurrence of cell debris released into the midgut lumen, cytoplasm rich in lipid droplets, autophagosomes, disorganized microvilli and deformed mitochondria. Data suggest that pyriproxyfen can be used to help to control and eradicate this insect vector.

37 citations


Journal ArticleDOI
TL;DR: It is demonstrated that spinosad negatively affects individual survival, general group activity and the midgut epithelium of P. helleri and the brain, on the other hand, did not present significant alterations under the tested conditions.

24 citations


Journal ArticleDOI
TL;DR: Sublethal exposure to CuSO4 induces changes in respiration, and spinosad changes the abundance of gut microorganisms of P. helleri, which is an important pollinator in the Neotropical region.

24 citations


Journal ArticleDOI
TL;DR: Females that developed from larvae treated with both the water extract and lectin-rich fraction showed reduced engorgement after a blood meal, with the consequent impairment of their fertility and fecundity, probably due to the damage to midgut organization and impairment of the remodeling process during metamorphosis.

16 citations


Journal ArticleDOI
TL;DR: Evaluating the effects of chronic oral exposure to spinosad during the larval phase on survival, developmental time, body mass, midgut epithelial remodeling, and the peritrophic matrix of Partamona helleri stingless bee workers suggests possible environmental risks for usingspinosad in cultures that are naturally pollinated by stingless bees.

15 citations


Journal ArticleDOI
TL;DR: Increased abilities to survive natural environmental challenges (e.g., predatory attacks) in mosquito larvae that express physiological and behavioral changes associated with multiple resistance to insecticides are revealed.

11 citations


Journal ArticleDOI
14 Mar 2019-Insects
TL;DR: This study describes the morphology and morphometry of the midgut in F. schrottkyi forager workers contributing to the comprehension of the digestive process of this bee.
Abstract: Friesella schrottkyi is a small stingless bee (3-mm long) important for agricultural and native forest pollination. This study describes the morphology and morphometry of the midgut in F. schrottkyi forager workers. The F. schrottkyi midgut presents a single-layered epithelium with digestive, regenerative and endocrine cells. The digestive cells are similar along the entire midgut length with a spherical nucleus, apex with long striated border, cytoplasmic granules in the apical region and well-developed basal labyrinth associated with mitochondria, suggesting they are multifunctional, synthesizing digestive enzymes and peritrophic matrix compounds and absorbing nutrients. Regenerative cells are located around the basal region organized in nests with some cells with a spherical nucleus. Phe-Met-Arg-Phe-NH₂-amide (FMRFamide) positive endocrine cells are restricted to the posterior midgut region, suggesting a paracrine function in the midgut. This is the first morphological description of the F. schrottkyi midgut contributing to the comprehension of the digestive process of this bee.

5 citations


Journal ArticleDOI
TL;DR: The changes that occur in the midgut during metamorphosis of Partamona helleri, a species of stingless bees found in Neotropical regions, are described to contribute to a better understanding of morphogenesis of the stingless bee digestive system.
Abstract: In this work, we describe the changes that occur in the midgut during metamorphosis of Partamona helleri, a species of stingless bees found in Neotropical regions. Morphology and immunofluorescence data were analysed in larvae, pupae and adults. The intestinal epithelium presented morphological variations between the different stages of development, including the size of the striated border. Cells undergoing apoptosis and autophagy were observed in practically all stages, with the autophagy process prevailing over apoptosis in most stages, except in post-defecating larvae. The quantity of cells in oxidative stress increased in the pupae stage, especially in the black-eyed and pink-eyed pupae, and decreased in the adult stage. Cell proliferation, on the other hand, was more evident in black-eyed pupae, mainly in the stage with the highest number of cells in autophagy. In general, the results contributed to a better understanding of morphogenesis of the stingless bee digestive system.

2 citations


Journal ArticleDOI
TL;DR: The basic plan of the adult heart was conserved across all the adult mosquitoes investigated in this study, and conserved organization was expected because this organ plays an important role in the maintenance of individual homeostasis.
Abstract: The heart is a pivotal organ in insects because it performs a number of different tasks, such as circulating nutrients, hormones, and excreta. In this study, the morphologies of the heart and associated tissues, including pericardial cells (PCs) and alary muscles (AMs), in the hematophagous mosquitoes Anopheles aquasalis Curry (Diptera: Culicidae), Aedes aegypti L. (Diptera: Culicidae), and Culex quinquefasciatus Say (Diptera: Culicidae), and the phytophagous Toxorhynchites theobaldi Dyar & Knab (Diptera: Culicidae) were compared using different microscopy techniques. Mosquito hearts are located across the median dorsal region of the whole abdomen. Paired incurrent openings in the heart wall (ostia) are found in the intersegmental regions (segments 2-7) of the abdomen, while an excurrent opening is located in the terminal cone of Ae. aegypti. The sides of the heart contain PC that are more numerous in An. aquasalis and Th. theobaldi. In these two species, PC form a cord of as closely aggregated cells, but in Ae. aegypti and Cx. quinquefasciatus, PC occur in pairs with two or four PC pairs per intersegmental region. In Th. theobaldi, AM binds to all regions of the heart, whereas in other mosquitoes they only bind in the intersegmental regions. The basic plan of the adult heart was conserved across all the adult mosquitoes investigated in this study. This conserved organization was expected because this organ plays an important role in the maintenance of individual homeostasis. However, the species had different PC and of AM morphologies. These morphological differences seem to be related to distinct physiological requirements of mosquito circulatory system.

2 citations


Journal ArticleDOI
TL;DR: The research evaluated live migration process overhead, on real and virtual environments, noticed from the client's side regarding two different services: web and database, finding the DB service accommodated better to the virtual environment and to migration than Web service.
Abstract: One important benefit of servers' virtualization is the reduction of the maintenance complexity of infrastructures. A key feature is servers' live migration which allows virtual servers to be exchanged between physical machines without stopping their services. However, virtualization also has some drawbacks caused by the overhead generated. Our research evaluated live migration process overhead, on real and virtual environments, noticed from the client's side regarding two different services: web and database. YCSB and ab Benchmark were adopted as workloads. Almost all tests on real environment overcame those on virtual, with both benchmarks. The impact of the live migration in the services was evident, proving to be more effective on real machines than on virtual machines. We found the DB service accommodated better to the virtual environment and to migration than Web service. We also considered an environment with multiple migrations which presented a higher degradation than when only one migration is performed.

1 citations