Morphological, histological, and ultrastructural characterization of degenerating salivary glands in females of the cattle-tick Rhipicephalus (Boophilus) microplus (CANESTRINI, 1887) (Acari : Ixodidae)

The present study describes the morphology and ultrastructure of the salivary glands of semi-engorged females of the southern cattle-tick Rhipicephalus (Boophilus) microplus. The acini that compose these glands, at that specific feeding stage, show cells featuring degenerative process of the salivary glands, such as: vacuolated cytoplasm, condensed chromatin, fragmented nuclei, and presence of apoptotic bodies. In addition, the presence of microorganisms was detected, with morphology typical of protozoa, inside these organs. (c) 2005 Elsevier Ltd. All rights reserved.

Protective effect of beta-glucan extracted from Saccharomyces cerevisiae, against DNA damage and cytotoxicity in wild-type (k1) and repair-deficient (xrs5) CHO cells

A large number of functional foods, including those that contain P-glucan, have been shown to prevent the development of cancer and other chronic diseases. The aim of the present study was to elucidate its mechanism of action, as well as to understand its effects as an antigenotoxic, anticlastogenic agent, and to determine its capacity to preserve cell viability. The investigation was carried out in the CHO-k1 and CHO-xrs5 cell lines. The cytokinesis-blocked micronucleus assay indicated that the different doses of beta-glucan examined (5, 10, 20 and 40 mu g/ml) did not show clastogenic effects. In the CHO-k1 cell line, a chemopreventive effect could be observed in all the protocols tested: pre-treatment (% reduction of 35.0-57.3), simultaneous treatment (simple - 5 reduction of 19.7-55.6 and with pre-incubation - of 42.7-56.4) and post-treatment (% reduction of 17.9-37.6). This finding indicates mechanisms of action involving desmutagenesis and bio-antimutagenesis, albeit the latter having a lesser role. However, in the repair-deficient CHO-xrs5 cells, beta-glucan did not show a protective effect with post-treatment (% reduction of 2.96), thus supporting the involvement of bioantimutagenesis. The comet assay in CHO-k1 cells demonstrated that beta-glucan has neither a genotoxic nor an antigenotoxic effect. Cell viability tests indicated that beta-glucan preserves cell viability in both cell lines, preventing apoptotic events. These findings suggest that beta-glucan, when present in foods, could provide them with nutraceutical characteristics and act as a dietary supplement, or that P-glucan could be used in new drug development. (c) 2006 Elsevier Ltd. All rights reserved.

Morphological characterization of cell death during the ovary differentiation in worker honey bee

Cell death that occurs during ovary differentiation in the honeybee worker's larval development accounts for ovariole reabsorption. From a morphological standpoint, three modes of death were detected. Germinative cells in the ovarioles die by an apoptotic-like process, whereas the somatic cells die by an autophagic process, type 11 cell death; and during pupation, stromatic and ovarian capsular cells die through cytoplasmic disintegration, releasing their components into the hemolymph. These modes of cell death are in part determined by the pattern of tissue organization within which the cell occurs. (C) 2002 Elsevier B.V. Ltd. All rights reserved.

Cytotoxic effects of permethrin in salivary glands of Rhipicephalus sanguineus (Latreille, 1806) (Acari: Ixodidae) semi-engorged females

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Fipronil-induced cell death in salivary glands of Rhipicephalus sanguineus (Latreille, 1806) (Acari: Ixodidae) semi-engorged females

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Degeneration of salivary glands of males of the tick Rhipicephalus sanguineus (Latreille, 1806) (Acari, Ixodidae)

The present study examined the salivary glands of Rhipicephalus sanguineus males at days 0, 3, and 7 post-detachment from the host. Degeneration of this organ occurred in the three stages and it advanced as time away from the host progressed. Thus, characteristics of degeneration were more prominent in males at day 7 post-detachment than in males at day 0 post-detachment. In males at day 0 post-detachment, type I acini were intact; while in other stages these acini exhibited signs of degeneration. In type 11 acini of individuals at day 0 post-detachment, cells a, c1-c5, c8, and indeterminate were identified. Only c I and c8 were intact. The remaining cell types were undergoing degeneration, as well as all cells d-f in type III acini, and all g in type IV acini.In males at day 3 post-detachment from the host, all cells (a, c1-c5, c8 and indeterminate) of type 11 acini, cells d and e in type III acini, and g in type IV were undergoing degeneration. In some Indeterminate acini, the boundaries of cells still could be distinguished, while in others, only a cytoplasmic mass was observed. At day 3 post-detachment, apoptotic bodies were present.In males at day 7 post-detachment from the host, the degeneration process progressed. All cells a, cl, c3-c5, c8 and indeterminate in type II, and d and e in type III acini were undergoing degeneration. Type IV acini still contained remnants of secretion and in Indeterminate acini, only a cytoplasmic mass could be observed. At this stage, apoptotic bodies were also present.The present study still revealed that cells of salivary glands of R. sanguineus males when degenerating undergo the following changes: (a) decrease in secretion production with or without granule breakage, (b) changes in nuclear morphology, (c) cytoplasm shrinkage, (d) loss of cell shape, (e) loss of cell boundaries, and (e) cytoplasmic vacuolation. Together, these changes result in cell fragmentation with release of apoptotic bodies. (C) 2008 Elsevier B.V. All rights reserved.

Nuclear alterations associated to programmed cell death in larval salivary glands of Apis mellifera (Hymenoptera : Apidae)

The silk glands of bees are a good model for the study of cell death in insects. With the objective to detect the nuclear features during glandular regression stage, larvae at the last instar and pre-pupae were collected and their silk glands were dissected and processed for ultrastructural analysis and histologically for cytochemical and imunocytochemical analysis. The results showed that the cellular nuclei exhibited characteristics of death by atypical apoptosis as well as autophagic cell death. Among the apoptosis characteristic were: nuclear strangulation with bleb formation in some nuclei, DNA fragmentation in most of the nuclei and nucleolar fragmentation. Centripetal chromatin compaction was observed in many nuclei, forming a perichromatin halo differing from typical apoptotic nuclei. With regards to the characteristics of autophagic-programmed cell death, most relevant was the delay in the collapse of many nuclei. (C) 2006 Elsevier Ltd. All rights reserved.

Cytoplasmic RNA and nuclear changes detected cytochemically during the degeneration of salivary glands of the tick Rhipicephalus sanguineus (Latreille, 1806) (Acari, Ixodidae)

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Record of mimetism between mites and eggs of the neotropical termite Cornitermes cumulans (Isoptera : Termitidae)

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Mastoparan effects in skeletal muscle damage: An ultrastructural view until now concealed

Animal venoms have been valuable sources for development of new drugs and important tools to understand cellular functioning in health and disease. The venom of Polybia paulista, a neotropical social wasp belonging to the subfamily Polistinae, has been sampled by headspace solid phase microextraction and analyzed by gas chromatography-mass spectrometry. Recent study has shown that mastoparan, a major basic peptide isolated from the venom, reproduces the myotoxic effect of the whole venom. In this study, Polybia-MPII mastoparan was synthesized and studies using transmission electron microscopy were carried out in mice tibial anterior muscle to identify the subcellular targets of its myotoxic action. The effects were followed at 3 and 24 h, 3, 7, and 21 days after mastoparan (0.25 mu g/mu L) intramuscular injection. The peptide caused disruption of the sarcolemma and collapse of myofibril arrangement in myofibers. As a consequence, fibers presented heteromorphic amorphous masses of agglutinated myofilaments very often intermingled with denuded sarcoplasmic areas sometimes only surrounded by a persistent basal lamina. To a lesser extent, a number of fibers apparently did not present sarcolemma rupture but instead appeared with multiple small vacuoles. The results showed that sarcolemma, sarcoplasmic reticulum (SR), and mitochondria were the main targets for mastoparan. In addition, a number of fibers showed apoptotic-like nuclei suggesting that the peptide causes death both by necrosis and apoptosis. This study presents a hitherto unexplored view of the effects of mastoparan in skeletal muscle and contributes to discuss how the known pharmacology of the peptide is reflected in the sarcolemma, SR, mitochondria, and nucleus of muscle fibers, apparently its subcellular targets.

Death by apoptosis in salivary glands of females of the tick Rhipicephalus sanguineus (Latreille, 1806) (Acari : Ixodidae)

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Spontaneous germ cell death by apoptosis in epididymis of the adult bat Artibeus lituratus

Many factors can lead cells to apoptosis during the various stages of cell life. This study was undertaken to characterize germ cell death in the epididymis of the adult Artibeus lituratus by histochemical and immunohistochemical techniques using light microscopy and transmission electron microscopy. The results showed that cells with a nuclear phenotype and ultrastructural characteristics of chromatin compaction were common in apoptosis. The Apoptag test confirmed that the suspected cells were apoptotic. It is suggested that immature germ cells, when released from the germinative epithelium, may be directed towards the epididymis instead of being disposed of in the testicle. Furthermore, intact immature cells can leave the testicle in the initial phases of apoptosis and complete this phenomenon in the epididymis.

Tissue changes in senescent gerbil prostate after hormone deprivation leads to acquisition of androgen insensitivity

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Exposure of young rats to high estrogen doses leads to degeneration of elongated spermatids

Single high doses of estrogen (35 mg/kg body weight) were administered to young rats aiming to exacerbate its effects on germ cell populations. The short-term (1 week) and medium-term (7 weeks) consequences of this estrogenic treatment (ET) on the testis were evaluated using light and electron microscopies, quantitative methods and TUNEL reaction. Short-term ET led to 50% atrophy of the testis, however, in the medium term the gonado-somatic index was recovered. No histopathological alterations were found at seminiferous epithelium except for short-term severe degeneration of elongated spermatids (EL) and low frequency of these cells in both time intervals. Two morphologically distinct patterns of degeneration were observed: (1) clusters of EL which were TUNEL-negative and exhibited bizarre appearance and nuclear fragmentation, (2) isolated apoptotic EL within the cytoplasm of Sertoli cells (SC). Both degenerative phenomena were more frequent in stages III - VIII of seminiferous cycle, whereas at stages I and II only coiling of flagellum was observed. One week after ET, small amounts of EL were detected in stages IX - XII, suggesting spermiation failure. Signs of functional SC damage such as an accumulation of myelin-like inclusions in their cytoplasm were observed in the short but not medium-term. However, the apoptotic rates still remained five times higher and the number of elongated spermatids was three-fold lower. Our data indicate that exposure to a high dose of estrogen around puberty has stage-specific effects on the testis and causes massive degeneration of elongated spermatids. (c) 2007 Elsevier Ltd. All rights reserved.

Cyclosporin A causes impairment of the ventral prostate tissue structure of Wistar rats

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)