Caracterização morfofisiológica dos hemócitos do Diplópodo Rhinocricus padbergi antes e após exposição a substrato contendo lodo de esgoto

Embora os invertebrados sejam conhecidos pela grande facilidade de acúmulo de poluentes presentes em seu ambiente, e muitos serem utilizados como espécies sentinelas em estudos de biomonitoramento, pouco ainda é conhecido sobre o impacto de toxicantes sobre o sistema imune desses animais. Nesse sentido, os hemócitos desempenham um papel fundamental: estas células circulam livremente através da hemolinfa dos invertebrados e atuam no reconhecimento de materiais estranhos ao organismo, mediando e efetuando reações de defesa celular. Diferentes tipos morfológicos podem ser reconhecidos, mas ainda há controvérsia entre os pesquisadores sobre a exata classificação dos hemócitos, devido à diversidade de técnicas para preservação e observação dessas células. A classificação mais aceita atualmente agrupa os hemócitos em sete tipos principais: pró-hemócitos, plasmatócitos, granulócitos, esferulócitos, adipohemócitos, oenocitóides e coagulócitos. Por meio da utilização de técnicas histológica, histoquímica e ultra-estrutural, o presente trabalho objetivou caracterizar morfofisiologicamente os hemócitos circulantes na hemolinfa do diplópodo Rhinocricus padbergi, bem como aqueles encontrados por entre as células da camada de corpo gorduroso no intestino médio de animais expostos a substratos contendo diferentes amostras de lodo de esgoto, resíduo gerado nas Estações de Tratamento de Esgoto (ETEs). Este resíduo tem sido cogitado como um bom condicionador de solo em áreas degradadas e como um potencial fertilizante agrícola, apesar do risco de estar contaminado com patógenos e/ou metais pesados. A partir das análises realizadas, foram identificados três tipos morfológicos distintos de hemócitos circulantes na hemolinfa dessa espécie: pró-hemócitos, plasmatócitos e granulócitos (subtipos I e II). Também foram observadas células com características...Although invertebrates are known for ease accumulation of pollutants present in their environment and several are used as sentinel species in biomonitoring studies, little is known about the impact of toxicants on the immune system of these animals. In this sense, hemocytes play an important role: these cells circulate freely through the hemolymph of invertebrates and act in the recognition of foreign materials to the organism, mediating and performing cellular defence reactions. Different morphological types are recognized, but there is still controversy among the researchers about the exact classification of the hemocytes due to the diversity of techniques for preservation and observation of these cells. Currently, the most accepted classification groups the hemocytes into seven main types: pro-hemocytes, plasmatocytes, granulocytes, spherulocytes, adipohemocytes, oenocytoids and coagulocytes. By histological, histochemical and ultra-structural techniques, the present study aimed to characterize morpho-physiologically the hemocytes circulating in the hemolymph of the diplopod Rhinocricus padbergi, as well as those found among the cells of the fat body layer of the midgut of animals exposed to substrates containing samples of sewage sludge, residue generated in the Sewage Treatment Plants (STPs). This residue has been considered as a good soil conditioner on degraded areas and as a potential agricultural fertilizer, despite the risk of being contaminated with pathogens and/or heavy metals. From the analyses carried out, it was identified three distinct morphological types of hemocytes circulating in the hemolymph of this species: pro-hemocytes, plasmatocytes and granulocytes (subtypes I and II). It was also observed cells with intermediate characteristics between pro-hemocytes and plasmatocytes, suggesting a probable cellular differentiation in the hemolymph... (Complete abstract click electronic access below)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES

Hemocitical responses to environmental stress in invertebrates: a review

Although invertebrates are recognized by the great facility to accumulate pollutants present in their environment and many of them are used as sentinel species in biomonitoring studies, little is known about the impact of toxicants on the immune system of these animals. In this regard, hemocytes play a fundamental role: these cells circulate freely through the hemolymph of invertebrates and act on the recognition of foreign material to the organism, mediating and effecting the cellular defense, such as phagocytosis, nodulation, and encapsulation. Different morphological types can be recognized but still there is controversy among the researchers about the exact classification of the hemocytes due to the diversity of techniques for the preservation and observation of these cells. In the present study, a review on the main hemocyte responses to environmental stress in different invertebrate organisms is presented, emphasizing the contamination by heavy metals. It is discussed parameters such as: alteration in the number of cells involved in the defense reaction, phagocytic activity, lysosomal responses, and production of reactive oxygen species.Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES

Assessment of the Toxic Potential of Sewage Sludge in the Midgut of the Diplopod Rhinocricus padbergi

The destination of sewage sludge is a problem faced by sewage treatment plants (STPs). Many alternatives have been sought, such as the application of sewage sludge in degraded soils and in agriculture as fertilizer. However, due to the risk of contamination with pathogens and/or metals, the use of sludge should be done cautiously. By the habits that diplopods present, they have been considered good environmental indicators for soil analysis. In this study, animals from the Rhinocricus padbergi species were exposed to two sewage sludge samples from two STPs in the So Paulo State, for different periods. The midgut of the animals were removed and histologically processed and subjected to histochemical tests. It was detected the following tissular responses: clusters of haemocytes through the cells of the fat body layer, increase in the quantity of intracellular granules in the cells of the fat body layer, increase in the release of secretion vesicles of the intestinal epithelium, and intense vacuolization of the cytoplasm of epithelial cells. The results suggest the presence of toxic substances to the studied species in both sludge samples used.Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq