RESUMO
The effects of biopesticides on insects can be demonstrated by morphological and ultrastructural tools in ecotoxicological analysis. Azadirachtin-based products are widely used as biopesticides, affecting numerous insect populations. Through morphological biomarkers, this study aimed to characterize the fat bodies of both the southern armyworm Spodoptera eridania and the predator Ceraeochrysa claveri after chronic exposure to azadirachtin. Larvae of S. eridania and C. claveri were fed with fresh purple lettuce leaves (Lactuca sativa) and egg clusters of Diatraea saccharalis treated with azadirachtin solution of 6 mg active ingredient (a.i.)/L and 18 mg a.i./L for 7 days, respectively. The biological data showed a significant reduction in survival and body mass in S. eridania and cytotoxic effects in the parietal and perivisceral fat bodies in both species. Ultrastructural cell damage was observed in the trophocytes of both species such as dilated cisternae of the rough endoplasmic reticulum and swollen mitochondria. Trophocytes of S. eridania and C. claveri of the parietal and perivisceral layers responded to those injuries by different cytoprotective and detoxification means such as an increase in the amount of cytoplasmic granules containing calcium, expression of heat shock protein (HSP)70/HSP90, and development of the smooth endoplasmic reticulum. Despite all the different means of cytoprotection and detoxification, they were not sufficient to recover from all the cellular damages. Azadirachtin exhibited an excellent performance for the control of S. eridania and a moderate selectivity for the predator C. claveri, which presents better biological and cytoprotective responses to chronic exposure to azadirachtin.
Assuntos
Corpo Adiposo/fisiologia , Limoninas/farmacologia , Neópteros/fisiologia , Controle Biológico de Vetores , Comportamento Predatório , Spodoptera/fisiologia , Animais , Bioensaio , Corpo Adiposo/citologia , Corpo Adiposo/efeitos dos fármacos , Corpo Adiposo/ultraestrutura , Larva/efeitos dos fármacos , Larva/ultraestrutura , Neópteros/efeitos dos fármacos , Neópteros/ultraestrutura , Spodoptera/efeitos dos fármacos , Spodoptera/ultraestruturaRESUMO
The in vivo subcellular localization of Mal de Río Cuarto virus (MRCV, Fijivirus, Reoviridae) non-structural proteins fused to GFP was analyzed by confocal microscopy. P5-1 showed a cytoplasmic vesicular-like distribution that was lost upon deleting its PDZ binding TKF motif, suggesting that P5-1 interacts with cellular PDZ proteins. P5-2 located at the nucleus and its nuclear import was affected by the deletion of its basic C-termini. P7-1 and P7-2 also entered the nucleus and therefore, along with P5-2, could function as regulators of host gene expression. P6 located in the cytoplasm and in perinuclear cloud-like inclusions, was driven to P9-1 viroplasm-like structures and co-localized with P7-2, P10 and α-tubulin, suggesting its involvement in viroplasm formation and viral intracellular movement. Finally, P9-2 was N-glycosylated and located at the plasma membrane in association with filopodia-like protrusions containing actin, suggesting a possible role in virus cell-to-cell movement and spread.
Assuntos
Reoviridae , Spodoptera/virologia , Proteínas não Estruturais Virais/análise , Proteínas não Estruturais Virais/fisiologia , Animais , Linhagem Celular , Membrana Celular/química , Membrana Celular/virologia , Núcleo Celular/química , Núcleo Celular/virologia , Citoplasma/química , Citoplasma/virologia , Citoesqueleto/virologia , Genoma Viral , Proteínas de Fluorescência Verde/genética , Microscopia Confocal , Proteínas Recombinantes de Fusão/análise , Reoviridae/genética , Reoviridae/fisiologia , Spodoptera/ultraestrutura , Frações Subcelulares/química , Frações Subcelulares/virologia , Proteínas não Estruturais Virais/genéticaRESUMO
A truncated version of the cry1Ca gene from Bacillus thuringiensis was introduced into the genome of Autographa californica multiple nucleopolyhedrovirus (AcMNPV) under the control of two promoters. A recombinant virus (vSyncry1c) was isolated and used to infect insect cells in culture and insect larvae. Structural and ultrastructural analysis of insects infected with vSyncry1C showed the formation of large cuboidal crystals inside the cytoplasm of insect cells in culture and in insect cadavers late in infection. Infected insect cell extracts were analyzed by SDS-PAGE and Western blot and showed the presence of a 65-kDa polypeptide probably corresponding to the protease processed form of the toxin. Bioassays using purified recombinant toxin crystals showed a CL(50) of 19.49 ng/ml for 2(nd) instar A. gemmatalis larvae and 114.1 ng/ml for S. frugiperda.