Expression of caspase 3 in ovarian follicle cells of the lizard Podarcis sicula.

In this study, our aim was to determine whether caspase 3 plays a role, during previtellogenesis, in the ovarian follicular epithelium of the lizard Podarcis sicula. We investigated the presence and localization of proform and active caspase 3 by enzyme assay, Western blotting and immunocytochemistry. In parallel, a fragment of caspase 3 was cloned for the first time in this species, sequenced and used for in situ hybridization to localize messengers and analysed by a phylogenetic survey to shed light on its homology with reptilian caspases.

Responses to cadmium intoxication in the liver of the wall lizard Podarcis sicula.

This study examined the cytological and molecular effects of cadmium, a toxic heavy metal, in the liver of the Italian wall lizard Podarcis sicula. Cadmium was administered in single dose, by diet, to induce a concentration comparable with that measured in animals living in contaminated sites. For comparison, cadmium was also administered in multiple doses by food (chronic) or in a single dose intraperitoneally (i.

Morphological and biochemical analyses of otoliths of the ice-fish Chionodraco hamatus confirm a common origin with red-blooded species.

The morphology and composition of the three otoliths of the Antarctic ice-fish Chionodraco hamatus were studied by scanning electron microscopy and X-ray diffraction. The composition of the sagitta, lapillus and asteriscus protein matrices was also analysed by sodium dodecyl sulphate-polyacrylamide gel electrophoresis, western blots and confocal laser scanning microscopy to reveal the presence of and to localize the calcium-binding proteins calmodulin, calbindin and S-100. Morphological results indicated that the otoliths in this ice-fish were similar to those of Trematomus bernacchii, a red-blooded Antarctic species [B.

cGnRH II involvement in pyriform cell apoptosis.

We have investigated whether gonadotrophin-releasing hormone (GnRH) is involved in triggering the apoptotic death of pyriforms, the nurse cells that cooperate in oocyte growth during mid- to late previtellogenesis in the lizard Podarcis sicula. Our immunocytochemical analyses demonstrate that pyriforms express GnRH receptors and that, in late previtellogenesis, they are up-regulated by cGnRH II. The hormone however does not trigger receptor synthesis and activation, events that therefore must be under the control of other regulatory factors.

The immunomodulatory protein SV-IV protects serum-deprived cells against apoptosis but not against G0/G1 arrest: possible implications for the survival of implanting embryo.

Serum deprivation induced in human lymphoblastoid Raji cells oxidative stress-associated apoptotic death and G0/G1 cell cycle arrest. Addition into culture medium of the immunomodulatory protein Seminal vesicle protein 4 (SV-IV) protected these cells against apoptosis but not against cycle arrest. The antiapoptotic activity was related to: (1) decrease of endocellular reactive Oxygen species (ROS) (2) increase of mRNAs encoding anti-oxidant enzymes (catalase, G6PD) and antiapoptotic proteins (survivin, cox-1, Hsp70, c-Fos); (3) decrease of mRNAs encoding proapoptotic proteins (c-myc, Bax, caspase-3, Apaf-1).

Block of mitochondrial apoptotic pathways in lizard ovarian follicle cells as an adaptation to their nurse function.

Pyriforms are ovarian follicle nurse cells that undergo apoptosis at the end of previtellogenesis and are completely eliminated by the epithelium. This event is accompanied by the active transfer of organelles and macromolecules to the oocyte via an intercellular bridge. Since it would be a nonsense for damaged mitochondria to reach the oocyte, we have postulated that pyriform cells have adapted their apoptotic machinery to prevent mitochondrial degradation.

Role of apoptosis and Fas/FasL system in the oogenesis of the spotted ray Torpedo marmorata.

In the present paper we investigated the role played by apoptosis during oogenesis in the cartilaginous fish Torpedo marmorata. TEM, TUNEL and immunohistochemical techniques were employed to specifically reveal morphological and biochemical hallmarks of apoptosis in specimens from birth to sexual maturity. Data obtained demonstrate that apoptosis occurs in prefollicular oocyte selection, in maintaining the homeostasis of granulosa in healthy growing oocyte and in resorbing atretic follicles.

Spherical bodies present within the germinal vesicle of Podarcis sicula previtellogenic oocyte derive from the temporaneous inactivation of ribosomal genes.

In the present paper we have investigated the origin of the spherical bodies (SBs) present within the germinal vesicle of about 400 microm previtellogenic oocytes in the lizard Podarcis sicula. In particular, we have attempted to clarify whether they derive from the single, large nucleolus present in early diplotenic oocyte as a consequence of ribosomal gene inactivation. We have, therefore, experimentally induced a decrease in rRNA synthesis by injecting animals with D-galactosamine or by exposing them to low temperatures.