Spermatogenesis and regulatory factors in the wall lizard Podarcis sicula.

Spermatogenesis is an extraordinarily complex process, regulated by several factors, which leads to the differentiation of spermatogonia into spermatozoa. Among vertebrates, several reports have been focused on the lizard Podarcis sicula, a seasonal breeder and a good model for the study of reproductive processes. The goal of this review is to resume all the available data about systemic and above all local control factors involved in the control of P.

Pituitary adenylate cyclase-activating peptide (PACAP) and its receptors in Mus musculus testis.

To enlighten the involvement of PACAP/receptors system in the control of mammal testis, we investigated the expression of PACAP and the localization of PACAP and its receptors PAC1, VPAC1, and VPAC2 in the testis of Mus musculus. By molecular and immunohistochemical investigations, we highlighted that PACAP and its receptors are widely represented in germ cells of Mus testis, particularly in spermatocytes I, spermatids, and spermatozoa, strongly suggesting their involvement in spermatogenesis process. Moreover, for the first time in the adult mouse testis we highlighted that PACAP is present within Leydig cells, as PACAP receptors, confirming its involvement in the control of steroidogenesis in mouse.

The expression of estrogen receptors during the Mytilus galloprovincialis ovarian cycle.

The aim of this paper is to assess, by real-time polymerase chain reaction and in situ hybridization, the expression of estrogen receptors ER1 and ER2 during the ovarian cycle of Mytilus galloprovincialis. By considering four phases of the reproductive cycle, that is stasis and previtellogenic stage (Stage 0), early vitellogenesis (Stage I), vitellogenesis (Stage II), full-grown oocyte (Stage III), our investigation demonstrates that the two receptors are differently expressed during the phases investigated of the ovarian cycle: ER1 reaches the highest level at Stage III, whereas ER2 reaches the highest level at Stage II, with ER2 always present at higher levels than ER1. The stage-dependent receptor expression was recorded within oocytes, follicle cells, and adipogranular cells.

Pituitary adenylate cyclase-activating polypeptide in the testis of the quail Coturnix coturnix: Expression, localization, and phylogenetic analysis.

To evaluate the involvement of pituitary adenylate cyclase-activating polypeptide (PACAP)/receptors system in the control of testis activity, we have investigated the expression and localization of PACAP and the distribution of its receptors in the testis of mature samples of quail Coturnix coturnix, and we have performed a phylogenetic analysis of PACAP in birds. Using histological, molecular, and bioinformatics tools, we demonstrated that (a) PACAP messenger RNA shows a high sequence identity with that reported in other birds studied so far and in other vertebrates. Furthermore, we showed that purifying selection acts on PACAP; (b) the PACAP peptide is present only in Leydig cells, whereas its receptors are localized within both Leydig and germ cells; (c) the synthesis of PACAP does not take place in seminiferous tubules.

The Mussel Mytilus galloprovincialis in the Bay of Naples: New Insights on Oogenic Cycle and Its Hormonal Control.

The aim of the present article was to investigate the oogenic cycle of Mytilus galloprovincialis sampled in the Bay of Naples, and to immunolocalize 3β-hydroxysteroid dehydrogenase (3β-HSD), 17β-hydroxysteroid dehydrogenase (17β-HSD), and P450 aromatase, enzymes involved in the synthesis of two sex hormones: testosterone and 17β-estradiol. We demonstrate that the oogenic cycle starts in late summer-early fall and continues in early winter when the first event of spawning occurs; other spawning events take place until June, when the ovary is spent and contains a few empty ovarian follicles and numerous somatic cells, that is, adipogranular cells and vesicular connective tissue cells. During the oogenic cycle, apoptotic events occur at the level of oogonia, previtellogenic oocytes, as well as follicle cells; by contrast, necrosis events probably take place in vitellogenic oocytes, which, once degenerated, transfer their content to healthy oocytes.

Spermatogenic Cycle and Steroidogenic Control of Spermatogenesis in Mytilus galloprovincialis Collected in the Bay of Naples.

The aim of the present article was to study the spermatogenic cycle of Mytilus galloprovincialis collected in the Bay of Naples during a whole year and to acquire new insights into the mechanism of control. Knowledge of the Mytilus cycle in this geographic area is of particular interest as, to the best of our knowledge, the male gonad cycle has been hitherto unexplored. Testis organization was evaluated together with the localization of the enzymes 3β-HSD, 17β-HSD, and P450-aromatase, which are strictly connected to the synthesis of two key hormones involved in the testis activity: testosterone and 17β-estradiol.

Role of PACAP on testosterone and 17β-estradiol production in the testis of wall lizard Podarcis sicula.

Pituitary adenylate cyclase-activating peptide (PACAP) is a neuropeptide that in mammalian testis is involved in the control of testosterone and 17β-estradiol synthesis. A similar involvement was recently postulated in the testis of a nonmammalian vertebrate, the wall lizard Podarcis sicula. Indeed, we reported the presence of PACAP and its receptors throughout the reproductive cycle within both germ and somatic cells.

Pituitary adenylate cyclase-activating peptide (PACAP) and PAC1 receptor in the testis of cartilaginous fish Torpedo marmorata: A molecular and phylogenetic study.

The role of PACAP in spermatogenesis and steroidogenesis has been largely investigated in last years in mammals; conversely, a few studies have been performed in non mammalian vertebrates. In this paper we investigated the sequence, expression and localization of PACAP and its PAC1 receptor in the testis of the benthic elasmobranch Torpedo marmorata, the marbled electric ray. Cloning a partial PACAP cDNA, we demonstrated for the first time in elasmobranches that PACAP shows a highly conserved sequence, compared with the PACAP of other chordates (tunicates and vertebrates).

Sex steroid hormone secretion in the wall lizard Podarcis sicula testis: The involvement of VIP.

Vasoactive intestinal peptide (VIP) is a pleiotropic neuropeptide involved in different functions, including testosterone synthesis. Recently, we reported the presence of VIP in the testis of Podarcis sicula, throughout the reproductive cycle. Now, we investigated the effects of the VIP on steroidogenesis in significant periods of the Podarcis reproductive cycle: winter stasis, reproductive period, and summer stasis.

PACAP and PAC₁ receptor in the reproductive cycle of male lizard Podarcis sicula.

Pituitary adenylate cyclase-activating peptide (PACAP) is a neuropeptide involved in multiple functions, including vertebrate reproduction. Recently, we reported the presence of PACAP in the testis of Italian wall lizard Podarcis sicula during reproductive period (May-June). Herein we investigated the PACAP mRNA expression and the localization of PACAP/PACAP receptor system, in the other periods of the Podarcis reproductive cycle, namely in summer stasis, early autumnal resumption, mid-autumnal resumption, winter stasis, and spring resumption.

Molecular cloning of VIP and distribution of VIP/VPACR system in the testis of Podarcis sicula.

Using molecular, biochemical, and cytological tools, we studied the nucleotide and the deduced amino acid sequence of PHI/VIP and the distribution of VIP/VPAC receptor system in the testis of the Italian wall lizard Podarcis sicula to evaluate the involvement of such a neuropeptide in the spermatogenesis control. We demonstrated that (1) Podarcis sicula VIP had a high identity with other vertebrate VIP sequences, (2) differently from mammals, VIP was synthesized directly in the testis, and (3) VIP and its receptor VPAC2 were widely distributed in germ and somatic cells, while the VPAC1 R had a distribution limited to Leydig cells. Our results demonstrated that in Podarcis sicula the VIP sequence is highly preserved and that this neuropeptide is involved in lizard spermatogenesis and steroidogenesis.

The VIP/VPACR system in the reproductive cycle of male lizard Podarcis sicula.

Starting from the knowledge that in the reproductive period the Vasoactive Intestinal Peptide (VIP) is widely distributed in Podarcis sicula testis, we studied VIP expression and the localization of the neuropeptide and its receptors in the testis of the Italian wall lizard P. sicula in the other phases of its reproductive cycle (summer stasis, autumnal resumption, winter stasis, spring resumption). By Real Time-PCR, we demonstrated that testicular VIP mRNA levels change during the reproductive cycle, showing a cyclic trend with two peaks, one in the mid-autumnal resumption and the other in the reproductive period.

Cellular localization of PACAP and its receptors in the ovary of the spotted ray Torpedo marmorata Risso 1880 (Elasmobranchii: Torpediniformes).

The pituitary adenylate cyclase-activating polypeptide (PACAP) is a member of the glucagon-related family and occurs in two amidated forms, PACAP38 and PACAP27, with 38 and 27 amino acids, respectively. PACAP acts by binding to three different receptors, that are classified by their binding affinity for PACAP and VIP (vasoactive intestinal polypeptide): PAC(1)R (PACAP-specific receptor) exclusively binds PACAP, while VPAC(1)R (VIP/PACAP receptor, subtype 1) and VPAC(2)R (VIP/PACAP receptor, subtype 2) bind both PACAP and VIP. PACAP, first discovered in the brain, was then localized in several peripheral tissues of mammals, including the ovary.

Expression of VIP and its receptors in the testis of the spotted ray Torpedo marmorata (Risso 1880).

The aim of this work was to study, by immunoprecipitation, in situ hybridization and immunohistochemistry, and the expression of the vasoactive intestinal peptide (VIP) and of its receptors (VPAC(1)R and VPAC(2)R) in the testis of a nonmammalian vertebrate, the cartilaginous fish Torpedo marmorata. We demonstrated that, differently from mammals, VIP and VPAC(2)R were widely distributed in the testicular cells while the VPAC(1)R had a limited distribution. In details, we showed that VIP and VPAC(2)R were present in mitotic and differentiating germ cells as well as in the cells involved in the steroidogenesis, i.

A network system for vitellogenin synthesis in the mussel Mytilus galloprovincialis (L.).

The aim of this study is to assess, by RT-PCR, in situ hybridization, electron microscopy, and immunohistochemistry, the site/s of vitellogenin (VTG) synthesis in the mussel Mytilus galloprovincialis. Our investigations demonstrate that, among the analyzed tissues, the synthesis of VTG occurs only in the female gonad, that is, within the oocyte and follicle and connective cells. Such a synthesis is just evident in early vitellogenic oocytes, whose cytoplasm is characterized by numerous RER cisternae and an extended Golgi complex surrounded by nascent yolk platelets.

Expression of vitellogenin receptor in the ovarian follicles during the reproductive cycle of the spotted ray Torpedo marmorata Risso 1880.

The aim of this investigation was to identify the encoding sequence of vitellogenin receptor gene (vtgr), and its expression during the oogenesis in the spotted ray, Torpedo marmorata, in different phases of reproductive cycle. From an ovarian cDNA of vitellogenic female, we obtained a fragment of 581 bp, which corresponds to a partial sequence encoding the vitellogenin receptor (VTGR) in Torpedo (accession number: gi/193244760). This sequence shows a high identity with the VTGR of other vertebrates, particularly Leucoraja erinacea (89% identity) and Squalus acanthias (84% identity).

Expression of vitellogenin in the testis and kidney of the spotted ray Torpedo marmorata exposed to 17β-estradiol.

In vertebrates, the liver was long thought to be the only site of vitellogenin (Vtg) production, but recent studies demonstrated that Vtg is also expressed in extrahepatic districts. The aim of this paper is to assess, by in situ hybridization and immunohistochemistry, the expression of Vtg in the testis and kidney of Torpedo marmorata exposed to 17β-estradiol (E(2)). In treated samples vtg mRNA and Vtg were detected contemporaneously only in the testis; differently the kidney cells were positive to Vtg antibody, but negative to vtg mRNA.

Pituitary adenylate cyclase-activating polypeptide and its receptor PAC1 in the testis of Triturus carnifex and Podarcis sicula.

The pituitary adenylate cyclase-activating polypeptide (PACAP) is a member of the glucagon-related family that occurs in two amidated forms with 38 (PACAP38) and 27 (PACAP27) amino acids. First discovered in the brain, it was then localized in several peripheral tissues of mammals, including the testis. However, current knowledge of the expression and function of PACAP and its receptor PAC(1) in the reproductive system of non-mammalian vertebrates, and particularly in the testis, is still limited.

Expression of Prothymosin alpha during the spermatogenesis of the spotted ray Torpedo marmorata.

In this study, we show that Prothymosin alpha (Ptma), a small, unfolded, negatively charged protein, is present in the cartilaginous fish Torpedo marmorata. The ptma gene is functional and peculiarly controlled during the male spermatogenesis of T. marmorata, as revealed by in situ hybridization and by immunocytochemistry studies.

Organization of the vitelline envelope in ovarian follicles of Torpedo marmorata Risso, 1810 (Elasmobranchii: Torpediniformes).

In Torpedo marmorata, the vitelline envelope (VE), an extracellular envelope surrounding the growing oocyte, consists of fibrils and amorphous materials that are deposited in the perivitelline space starting from the initial steps of oocyte growth. SDS-PAGE analysis of the isolated and purified VE reveals that it consists of different glycoproteins. Furthermore, our investigations showed that the 120 and 66 kDa glycoproteins are positive to an antibody directed against gp69/64 of the Xenopus laevis VE and are synthesized under the control of 17beta-estradiol in the liver, that, together follicle cells and the oocyte, is the biosynthetic site of VE components.