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Th is study presents the morphology of the ovary, as well as the dynamics of the vitellogenesis process in oocytes of the diplopod Urostreptus atrobrunneus (Spirostreptida, Spirostreptidae). Th e oocytes are arranged in clusters called ovisacs, which are distributed in a paired way along the body. Th e ovary is of the panoistic type. Diff erently from the other species of diplopods, it was observed little calcium in the oocytes of U. atrobrunneus . Lipids and proteins probably have double origin, i.e, endogenous and exogenous, with probable participation of the adjacent perivisceral fat body. Th e polysaccharides probably have exogenous origin with participation of the follicular epithelium in the synthesis and/or incorporation of these elements.

Ticks are hematophagous ectoparasites which can transmit several diseases to the host during their feeding process. When ticks mechanically damage the tissue, they eventually induce inflammatory responses on the skin spot where they are fixed. One of the alternatives to control these ectoparasites is the use of chemical substances like selamectin-the active principle of Pfizer's antiparasitic Revolution-a macrocyclic lactone capable of doing neurotoxic damage to the tick and eventually eliminating infestation in dogs and cats. The purpose of this study was to analyze, using histological and histochemical techniques, the occurrence of morphophysiological alterations in the skin of the host rabbits exposed to selamectin and infested with Rhipicephalus sanguineus (Acari: Ixodidae). Histologically, the exposed and infested rabbits showed a partial and/or total decrease in the stratum corneum and the epithelium decreased in the number of cell layers, consequently reducing the stratification (thinning) and quite pronounced formations of sub-epidermal edemas with consequent disorganization of collagen fibers in the dermal layer's connective tissue. Histochemical tests showed strong periodic acid-Schiff-positive reaction in the hair follicle and some regions of the dermis, besides resynthesis of collagen fibers detected by Mallory's trichrome technique. The obtained results showed that selamectin acts like a toxicant agent when in contact with the skin of the rabbit infested with ticks, inducing morphophysiological alterations in the acute inflammatory process in the animal's tegument. Selamectin is a chemical substance which has a dose-dependent action since higher concentrations cause greater morphophysiological damage in the skin of rabbits.

Diplopods are agile saprophagous invertebrates with the ability to colonize several soil layers. They feed on waste and decaying organic matter, making the soil in which they are present better aerated and mineral-enriched. Because of their habits, diplopods have been suggested to be used in studies to analyze possible toxic effects of impacted soils in edafic fauna. In that respect, this study aimed at checking the feasibility of using morphological analysis from millipede's midgut as a biomarker for soils exposed to sewage sludge from sewage treatment plants. Histological and histochemical techniques, applied to the species Rhinocricus padbergi's midgut, were used. Two sewage sludge samples were used; they were collected in two small towns in the countryside of São Paulo State. Both cities are part of the Piracicaba-Capivari-Jundiaí basin (PCJ-1 and PCJ-3). For 7 and 15-day periods, the animals were exposed to 10% concentrations and crude sludge for the PCJ-1sample and to 1, 10, and 50% concentrations and sludge for the PCJ-3 sample. The material exposed to the PCJ-1 sample showed an increase in the presence of cytoplasmic granules in both concentrations in all periods and a slight increase in the rate of epithelial renewal. The material of PCJ-3 sample presented the same alterations observed in PCJ-1 sample in higher frequence and over that high quantity of neutral polysaccharides in the hepatic cells layer. We can conclude that with the increase of sewage sludge concentrations tested, there is an increase in morphophysiologicals alterations frequencies found in the diplopods' midgut.

Ticks of Rhipicephalus sanguineus species have great medical and veterinary importance for being a vector of various diseases. In an attempt to minimize their action on the host, people have resorted to chemical control by using various acaricides, such as selamectin. Although previous studies have demonstrated its toxic action in domestic animals, no studies focused on the detection of cell death when exposed to selamectin. For this reason, the technique for detecting autophagic cell death was used in order to demonstrate the responses of rabbits' skin tissues pre-infested with R. sanguineus and exposed to different concentrations of selamectin. The obtained results when exposed to 100 and 80% concentrations of selamectin showed a strong mark of acid phosphatase on the cells of the connective tissue of the dermis and hair follicles, whereas the ones exposed to the 50% concentration had a weak mark on the cells of the connective tissue of the dermis and moderate staining in hair follicles. It became clear that, when used at high concentrations (100 and 80%), selamectin is capable to induce a large scale occurrence of the autophagic cell death process. On the other hand, the concentration of 50% causes minor morphophysiological changes in the skin of rabbit hosts when evaluated the cell death process. Therefore, the data confirms that selamectin is a powerful dose-dependent toxic agent causes increased activity of the enzyme acid phosphatase.

Due to the constant release of potentially harmful substances in the environment, it is necessary the use of biomonitoring as a form to assess the impact of these substances on animals that inhabit this environment. Therefore, there is a better understanding of the possible effects that these exogenous substances may cause in the organisms present there. In the present study it was verified the feasibility of the use of the diplopod Rhinocricus padbergi as bioindicator of impacted soils by their exposition to substrates containing different concentrations of sewage sludge from different Sewage Treatment Stations (STSs). It was observed animals' behavior and the survival rate was analyzed by log-rank test (p=0,05). The analysis showed that the animals exposed to pure sewage sludge presented higher mortality index than the specimens exposed to different concentrations of the sludge mixed with soil. In general, the survival rate and the analysis of the behavior of the diplopod R. padbergi showed efficiency of this species in biomonitoring impacted soils.Key words: millipede, sewage sludge, STS, toxicity. Biomonitoramento de substratos contendo lodo de esgoto: avaliação da viabilidade do uso do diplópodo Rhinocricus padbergi ResumoDiante da constante liberação de substâncias potencialmente danosas no ambiente, faz-se necessário o uso do biomonitoramento como forma de avaliar o impacto destas substâncias sobre os animais que os habitam. Com isso, tem-se uma maior compreensão dos possíveis efeitos que estes agentes exógenos podem causar nos organismos ali presentes. No presente estudo, verificou-se a viabilidade do uso do diplópodo Rhinocricus padbergi como bioindicador de solos impactados, por meio de sua exposição a substratos contendo diferentes concentrações de lodo de esgoto oriundo de diferentes Estações de Tratamento de Esgoto (ETEs). Foi observado o comportamento dos animais e a taxa de sobrevivência foi analisada pelo teste log-rank (p=0,05). As análises evidenciaram que os animais expostos ao lodo de esgoto puro apresentaram maior índice de mortalidade do que os espécimens expostos a diferentes concentrações de lodo misturado com terra. De um modo geral, a taxa de sobrevivência e a análise do comportamento do diplópodo R. padbergi demonstraram eficiência desta espécie no biomonitoramento de solos impactados.Palavras chave: milipede, lodo de esgoto, ETE, toxicidade. 50 J. Braz. Soc. Ecotoxicol. v.7, n. 1, 2012 Fontanetti et al.

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