Artigos
URI permanente para esta coleçãohttps://locus.ufv.br/handle/123456789/11845
Navegar
4 resultados
Resultados da Pesquisa
Item Morphology of the mandibular gland of the ant Paraponera clavata (Hymenoptera: Paraponerinae)(Microscopy Research and Technique, 2019) Andrade, Thito Thomston; Gonçalves, Wagner Gonzaga; Serrão, José Eduardo; Martins, Luiza Carla BarbosaThe ant Paraponera clavata (Fabricius, 1775) is the only extant species of Paraponerinae and is widely distributed in Brazilian forests. Aspects of its biology are documented extensively in the literature; however, knowledge of P. clavata internal morphology, specifically of exocrine glands, is restricted to the venom apparatus. The objective of this study was to describe the mandibular gland morphology of P. clavata workers. The mandibular gland is composed of a reservoir connected to a cluster of Type III secretory cells with cytoplasm rich in mitochondria and lipid droplets, similar to that of other ants. Notably, the glandular secretion is rich in protein and has a solid aspect. This is the first morphological description of the mandibular gland of P. clavata.Item Squamocin induce histological and ultrastructural changes in the midgut cells of Anticarsia gemmatalis (Lepidoptera: Noctuidae)(Ecotoxicology and Environmental Safety, 2018-07-30) Fiaz, Muhammad; Martínez, Luis Carlos; Costa, Marilza da Silva; Cossolin, Jamile Fernanda Silva; Plata-Rueda, Angelica; Gonçalves, Wagner Gonzaga; Sant’Ana, Antônio Euzébio Goulart; Zanuncio, José Cola; Serrão, José EduardoAnnonaceous acetogenins (Annona squamosa Linnaeus) comprises of a series of natural products which are extracted from Annonaceae species, squamocin proved to be highly efficient among those agents. Squamocin is mostly referred as a lethal agent for midgut cells of different insects, with toxic effects when tested against larva of some insects. In present study, LC50 and LC90 of squamocin for A. gemmatalis Hübner (Lepidoptera: Noctuidae) were calculated using probit analysis. Morphological changes in midgut cells were analyzed under light, fluorescence and transmission electron microscopes when larvae were treated with LC50 and LC90 of squamocin for 24, 48 and 72 h. Results revealed that the maximum damage to midgut cells was found under LC90 where it showed digestive cells with enlarged basal labyrinth, highly vacuolated cytoplasm, damaged apical surface, cell protrusions to the gut lumen, autophagy and cell death. The midgut goblet cells showed a strong disorganization of their microvilli. Likewise, in insects treated with squamocin, mitochondria were not marked with Mitotracker fluorescent probe, suggesting some molecular damage in these organelles, which was reinforced by decrease in the respiration rate in these insects. These results demonstrate that squamocin has potential to induce enough morphological changes in midgut through epithelial cell damage in A. gemmatalis.Item Toxicological and morphological effects of tebufenozide on Anticarsia gemmatalis (Lepidoptera: Noctuidae) larvae(Chemosphere, 2018-12) Fiaz, Muhammad; Martínez, Luis Carlos; Plata-Rueda, Angelica; Gonçalves, Wagner Gonzaga; Shareef, Muhammad; Zanuncio, José Cola; Serrão, José EduardoThe velvetbean caterpillar, Anticarsia gemmatalis Hübner (Lepidoptera: Noctuidae), is an important soybean pest in the Americas. Tebufenozide, a novel nonsteroidal ecdysone agonist is used to control this pest. Bioassays were conducted to assess tebufenozide toxicity and their ultrastructural effects on midgut of A. gemmatalis. The toxicity, survivorship, behavior response, and respiration rate for A. gemmatalis larvae after exposure to tebufenozide were evaluated. Also, A. gemmatalis larvae were treated with LC50 obtained from tebufenozide and changes were observed on their midgut cells after 24, 48 and 96 h. Tebufenozide was toxic to A. gemmatalis (LC50 = 3.86 mg mL−1 and LC90 = 12.16 mg mL−1) and survivorship was 95% for adults that had not been exposed to tebufenozide, decreasing to 52% with LC50 and 27% with LC90 estimated value. Damage to midgut cells was increased with exposure time. These cells show damaged striated border with release of protrusions to the midgut lumen, damaged nuclear membrane and nucleus with condensed chromatin and increase in amount of autophagic vacuoles. Mitochondria were modified into nanotunnels which might be an evidence that tebufenozide induces damage to cells, resulting in cell death, proved by immunofluorescence analyses. This insecticide also caused paralysis movement with change in homeostasis and compromised larval respiration. Thus, sublethal exposure to tebufenozide is sufficient to disturb the ultrastructure of A. gemmatalis midgut, which might compromise insect fitness, confirming tebufenozide a possible controlling insecticide.Item The rectum of Oxaea flavescens (Andrenidae) has a specialized structure among bees(Micron, 2003-11-10) Serrão, José Eduardo; Marques-Silva, Solange; Martins, Gustavo FerreiraThe rectum of the bee Oxaea flavescens contains six hollow rectal papillae, in contrast to rectal pads found in others Hymenoptera. The rectal epithelium is formed by cubical cells with structural specializations for fluid transport, such as apical plasma membrane invaginations, endocytic vesicles, scalariform junctions, wide extracellular space and double-membrane vesicles. Globular-shaped cells form the rectal papillae with surface plasma membrane invaginations that vary from small depressions to very large sinuses. The cell–cell contact is narrow, exhibiting extensive regions with scalariform junction, while cytoplasmic free ribosome-like material is prominent. These ultrastructural features are discussed in relation to their role in excretion in this bee.