Publications by authors named "Raissa Santana Serra"

3 Publications

  • Page 1 of 1

Behavioral and ultrastructural effects of novaluron on Aedes aegypti larvae.

Infect Genet Evol 2021 09 21;93:104974. Epub 2021 Jun 21.

Department of General Biology, Federal University of Viçosa, 36570-000 Viçosa, MG, Brazil. Electronic address:

Chitin synthesis inhibitors (CSI) are supposed to inhibit formation of chitin microfibrils in newly synthesized cuticle during molting process. Conversely, there has been comparatively few data on morphological effects of CSI on non-target insect organs. In this work, the effects of the CSI novaluron on behavior and midgut of A. aegypti were evaluated. Toxicity bioassays revealed that novaluron is toxic to A. aegypti larva with LC = 18.57 mg L when exposed in aqueous solution for 24 h. Novaluron treated larvae were less active and spent more time resting compared to the control group. Histopathology showed that midguts of novaluron-treated larvae had cytoplasm vacuolization and damaged brush border. Cytotoxic effects in midguts of treated larvae induced necrosis, autophagy and damage to mitochondria. Despite being chitin synthesis inhibitor, novaluron did not induce alterations in the integument of A. aegypti larvae. Fluorescence microscopy revealed that the number of digestive cells were higher in novaluron-treated larvae than in control, in response to digestive cell apoptosis. The present study highlights the importance of novaluron against A. aegypti larvae by causing injuries to non-target organs, altering behaviors, inducing cell death and inhibiting cell proliferation.
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http://dx.doi.org/10.1016/j.meegid.2021.104974DOI Listing
September 2021

Spiromesifen induces histopathological and cytotoxic changes in the midgut of the honeybee Apis mellifera (Hymenoptera: Apidae).

Chemosphere 2021 May 27;270:129439. Epub 2020 Dec 27.

Departamento de Biologia Geral, Universidade Federal de Viçosa, 36570-000, Viçosa, Minas Gerais, Brazil. Electronic address:

The honeybee Apis mellifera is an important pollinator that, similarly to other bees, undergoes colony losses due to several problems, including the use of pesticides in the agriculture. In addition to direct mortality, pesticides cause side-effects in some non-target organs, such as the midgut, which is the main organ for digestion and absorption. Spiromesifen is a pesticide used to control mites and whiteflies, which can be ingested by bees feeding on contaminated floral resources. This study evaluated the histopathological and cytological effects of the ingestion of spiromesifen on the midgut of A. mellifera workers. The bees were exposed per os to the field recommended dose of spiromesifen, and the midgut was analyzed after 24h and 48h of exposure to the pesticide. The midgut has a single layer of digestive cells, with spherical nucleus, nests of regenerative cells and layers of peritrophic matrix in the lumen. Bees treated with spiromesifen presented histological and cytological changes in the midgut, including disorganization of the epithelial architecture, release of cell fragments to the lumen, accumulation of mitochondria in the apical cytoplasm, alteration of the basal labyrinth, changes in the rough endoplasmic reticulum and cell degeneration. The occurrence of damage in the digestive cells of the A. mellifera midgut indicates that spiromesifen does not cause mortality in honeybees, but its side-effects can damage the midgut, which may affect the longevity and behavior of this pollinator.
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http://dx.doi.org/10.1016/j.chemosphere.2020.129439DOI Listing
May 2021

Cytotoxic effects on the midgut, hypopharyngeal, glands and brain of Apis mellifera honey bee workers exposed to chronic concentrations of lambda-cyhalothrin.

Chemosphere 2020 Jun 30;248:126075. Epub 2020 Jan 30.

Departamento de Biologia Geral, Universidade Federal de Viçosa, 36570-000, Viçosa, Minas Gerais, Brazil. Electronic address:

The honeybee, Apis mellifera is economically important for its products (honey, wax, and propolis) and for its role in pollination. This insect is threated due to high population losses in both agriculture and beekeeping. Within causes involved in the loss of honeybees is the increased pesticide use on agriculture. Although current testing for the regularization of insecticide use considers its acute toxic effects on pollinators, little is known about the effects of chronic exposure to sublethal concentrations that may persist in the environment. This study investigated the effect of chronic exposure to sublethal concentrations of lambda-cyhalothrin on the midgut, hypopharyngeal glands, and brain of A. mellifera. Honey bees were fed for eight days with LC insecticide. Subsequently, the midgut, hypopharyngeal glands, and brain were analyzed in light and transmission electron microscopies. The midgut was not affected after exposure, except in the posterior region with cell fragments in the lumen and changes in the mitochondria. The hypopharyngeal glands were severely affected by the insecticide with changes in the rough endoplasmic reticulum and cell death. The brain has extensive gaps in the neuropil as well as in the cellular bodies, especially in the corpora pedunculata. These resembled cellular alterations similar to those seen in death processes. The results of this study indicate that lambda-cyhalothrin is toxic to bees at sublethal concentrations and ingested chronically, causing damage to the midgut, hypopharyngeal glands, and brain, and may affect physiological and behavioral aspects of these insects.
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http://dx.doi.org/10.1016/j.chemosphere.2020.126075DOI Listing
June 2020
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