Proopiomelanocortin gene expression in the ovary of the frog, Rana esculenta.

The presence of proopionmelanocortin (POMC)-like mRNA has been demonstrated in a variety of extrapituitary tissues including hypothalamus,1 placenta,2 ovary,2 and testis.3 In amphibians, the POMC gene is actively expressed in the pituitary, both in melanotrope cells of the pars intermedia and in corticotrope cells of the pars distalis. 4–6 POMC gene expression in peripheral organs has also been investigated in Rana esculenta,7 indicating that POMC is actually synthetized in the ovary. Previous studies have shown that POMC-derived peptides are involved in local control of ovarian function and display seasonal changes.8,9 The aim of the present work was to develop a competitive reverse transcriptase polymerase chain reaction (RT-PCR) method using a synthetic, deletion mutant of POMC cRNA as an internal standard in order to quantify the amount of POMC mRNA in the ovary of Rana esculenta

Probiotic-Based Nutritional Effects on Killifish Reproduction

Probiotic bacteria used as dietary additives seem to offer an attractive choice inducing overall health benefits to the host organism. It is well known that reproduction, in all vertebrates, is regulated by the reproductive axis and that nutrition affects reproductive events, from puberty to adult gametogenesis, in both sexes. Consequently, reproductive events are very closely aligned with the nutrition. The aims of this study were to investigate the effects of dietary probiotic administration on the marine teleost Fundulus heteroclitus and the effects of such broodstock dietary treatment on the growth and survival of the new progeny. Lactobacillus rhamnosus IMC 501® was administered daily as a feed additive, at a final concentration of 106 cfu ml-1 for 8 days. Gonadal growth (gonadosomatic index, GSI), fecundity, embryo survival and hatching rate of larvae from broodstock fed probiotic-supplemented diets were analysed as well as the biometric parameters (body weight, BW; total length, TL). The results demonstrated the beneficial effects of probiotics on the reproductive performance of this marine teleost, as the GSI, fecundity and embryo survival were significantly enhanced by probiotic administration. On the contrary, no effect on the hatching rate was shown. Moreover, broodstock probiotic-based nutrition affected the early stages of larval development of the new progeny: in detail, a significantly higher TL was shown throughout the experiment in the progeny derived from the probiotic (PRO) group bloodstocks compared to the control (CTRL) group; mean BW was significantly higher only at 30 days post-hatching (dph) while no change was observed in terms of larval survival. These results confirmed the positive effect of L. rhamnosus IMC 501® on the reproductive process of this marine teleost, but further work is required to better understand the mechanisms by which probiotics act on the reproductive axis as well as the nutritionally-/immunologically-mediated maternal effects on embryo and larval development and growth

Probiotic Pediococcus acidilactici modulates both localised intestinal- and peripheral-immunity in tilapia (Oreochromis niloticus).

The application of probiotics in aquaculture has received concerted research efforts but the localised intestinal immunological response of fish to probiotic bacteria is poorly understood. Therefore, a study was conducted to evaluate the probiotic effect of Pediococcus acidilactici on Nile tilapia (Oreochromis niloticus) with specific emphasis on intestinal health and probiotic levels as well as system level responses such as growth performance, feed utilization and haemato-immunological parameters under non-challenged conditions. Fish (9.19 ± 0.04 g) were fed either a control diet or a P. acidilactici supplemented diet (at 2.81 × 10(6) CFU g(-)(1)) for six weeks. At the end of the study the probiotic was observed to populate the intestine, accounting for ca. 3% (1.59 × 10(5) CFU g(-)(1)) of the cultivable intestinal bacterial load. Real-time PCR indicated that the probiotic treatment may potentiate the immune-responsiveness of the intestine as up-regulation of the gene expression of the pro-inflammatory cytokine TNFα was observed in the probiotic fed fish (P 0.05)

Polydatin beneficial effects in zebrafish larvae undergoing multiple stress types

none8noPolydatin is a polyphenol, whose beneficial properties, including anti-inflammatory and antioxidant activity, have been largely demonstrated. At the same time, copper has an important role in the correct organism homeostasis and alteration of its concentration can induce oxidative stress. In this study, the efficacy of polydatin to counteract the stress induced by CuSO4 exposure or by caudal fin amputation was investigated in zebrafish larvae. The study revealed that polydatin can reduced the stress induced by a 2 h exposure to 10 µM CuSO4 by lowering the levels of il1b and cxcl8b.1 and reducing neutrophils migration in the head and along the lateral line. Similarly, polydatin administration reduced the number of neutrophils in the area of fin cut. In addition, polydatin upregulates the expression of sod1 mRNA and CAT activity, both involved in the antioxidant response. Most of the results obtained in this study support the working hypothesis that polydatin administration can modulate stress response and its action is more effective in mitigating the effects rather than in preventing chemical damages.openPessina A.; Di Vincenzo M.; Maradonna F.; Marchegiani F.; Olivieri F.; Randazzo B.; Gioacchini G.; Carnevali O.Pessina, A.; Di Vincenzo, M.; Maradonna, F.; Marchegiani, F.; Olivieri, F.; Randazzo, B.; Gioacchini, G.; Carnevali, O

Divergent male androgen patterns in two sympatric species of Leptodactylus from subtropical South America

Leptodactylus ocellatus L. is sympatric with L. chaquensis Cei on the banks of the Parana river, yet does not show evident gametogenic discontinuity or cyclical variation of secondary sex characters compared with the striking and well-defined seasonal rhythm found in L. chaquensis. The endocrine mechanisms regulating the seasonal reproductive cycle in the male of both species in their sympatric area have been studied through assessment of plasma androgens, related to the morphological examination of testis. A sudden intense spermatogenic activity was recorded in the testes of L. chaquensis in spring months (September-October), but this ceased in late November, and was followed by a strikingly long summer rest. Conversely, few morphological changes in L. ocellatus were found, since the mating period is more irregular and extensive. The androgen plasma changes paralleled the morphological observations. The plasma androgens behaved differently in the two species, since in L. chaquensis the androgen peak values occurred at the end of the intense spermatogenic activity, accompanied by dramatic increase of testicular weight and spermiation, while in L. ocellatus, the highest androgen plasma levels, occurring in August, seemed to indicate a precocious reproductive activity in this species. These data are discussed, in view of the pivotal role played by androgens in regulating the discontinuous reproductive cycle of L. chaquensis.Material digitalizado en SEDICI gracias a la colaboración del Dr. Jorge Williams (FCNM-UNLP).Facultad de Ciencias Naturales y Muse

Divergent male androgen patterns in two sympatric species of Leptodactylus from subtropical South America

Leptodactylus ocellatus L. is sympatric with L. chaquensis Cei on the banks of the Parana river, yet does not show evident gametogenic discontinuity or cyclical variation of secondary sex characters compared with the striking and well-defined seasonal rhythm found in L. chaquensis. The endocrine mechanisms regulating the seasonal reproductive cycle in the male of both species in their sympatric area have been studied through assessment of plasma androgens, related to the morphological examination of testis. A sudden intense spermatogenic activity was recorded in the testes of L. chaquensis in spring months (September-October), but this ceased in late November, and was followed by a strikingly long summer rest. Conversely, few morphological changes in L. ocellatus were found, since the mating period is more irregular and extensive. The androgen plasma changes paralleled the morphological observations. The plasma androgens behaved differently in the two species, since in L. chaquensis the androgen peak values occurred at the end of the intense spermatogenic activity, accompanied by dramatic increase of testicular weight and spermiation, while in L. ocellatus, the highest androgen plasma levels, occurring in August, seemed to indicate a precocious reproductive activity in this species. These data are discussed, in view of the pivotal role played by androgens in regulating the discontinuous reproductive cycle of L. chaquensis.Material digitalizado en SEDICI gracias a la colaboración del Dr. Jorge Williams (FCNM-UNLP).Facultad de Ciencias Naturales y Muse

Divergent male androgen patterns in two sympatric species of Leptodactylus from subtropical South America

Leptodactylus ocellatus L. is sympatric with L. chaquensis Cei on the banks of the Parana river, yet does not show evident gametogenic discontinuity or cyclical variation of secondary sex characters compared with the striking and well-defined seasonal rhythm found in L. chaquensis. The endocrine mechanisms regulating the seasonal reproductive cycle in the male of both species in their sympatric area have been studied through assessment of plasma androgens, related to the morphological examination of testis. A sudden intense spermatogenic activity was recorded in the testes of L. chaquensis in spring months (September-October), but this ceased in late November, and was followed by a strikingly long summer rest. Conversely, few morphological changes in L. ocellatus were found, since the mating period is more irregular and extensive. The androgen plasma changes paralleled the morphological observations. The plasma androgens behaved differently in the two species, since in L. chaquensis the androgen peak values occurred at the end of the intense spermatogenic activity, accompanied by dramatic increase of testicular weight and spermiation, while in L. ocellatus, the highest androgen plasma levels, occurring in August, seemed to indicate a precocious reproductive activity in this species. These data are discussed, in view of the pivotal role played by androgens in regulating the discontinuous reproductive cycle of L. chaquensis.Material digitalizado en SEDICI gracias a la colaboración del Dr. Jorge Williams (FCNM-UNLP).Facultad de Ciencias Naturales y Muse

Changes in Plasma Sex Steroids in Females of Two Sympatric Leptodactylus from Subtropical South America

Leptodactylus ocellatus is a well-known neotropical anuran in Argentina and Brazil, typically inhabiting marshes and streams, from sea level to 1000-1200 m in the Pampean mountains. Leptodactylus ocellatus is sympatric with L. chaquensis in Paraguay and on the Parana borders. Previous work (Cei, 1948,1949,1950,1980; Cei et al., 1955) with these two sibling species, L. ocellatus and L. chaquensis, revealed diversity in their reproductive cycles. Leptodactylus ocellatus exhibits less gametogenetic discontinuity and variety of secondary sex characters; the annual ovarian cycle of L. chaquensis, involves a fallwinter period of atresia for the residual mature oocytes from the former cycle, and at the same time a progressive auxocytic activity. The spring-summer period of mating and egg-laying of L. chaquensis is followed by resorption of retained oocytes. Moreover, in both sexes, a striking seasonal rhythm in the development of secondary sex characters has been found, together with dramatic growth of skeletal humeri and significant variation in serum calcium values (Cohen 1962a, b, 1963).Material digitalizado en SEDICI gracias a la colaboración del Dr. Jorge Williams (FCNM-UNLP).Facultad de Ciencias Naturales y Muse

Changes in Plasma Sex Steroids in Females of Two Sympatric Leptodactylus from Subtropical South America

Leptodactylus ocellatus is a well-known neotropical anuran in Argentina and Brazil, typically inhabiting marshes and streams, from sea level to 1000-1200 m in the Pampean mountains. Leptodactylus ocellatus is sympatric with L. chaquensis in Paraguay and on the Parana borders. Previous work (Cei, 1948,1949,1950,1980; Cei et al., 1955) with these two sibling species, L. ocellatus and L. chaquensis, revealed diversity in their reproductive cycles. Leptodactylus ocellatus exhibits less gametogenetic discontinuity and variety of secondary sex characters; the annual ovarian cycle of L. chaquensis, involves a fallwinter period of atresia for the residual mature oocytes from the former cycle, and at the same time a progressive auxocytic activity. The spring-summer period of mating and egg-laying of L. chaquensis is followed by resorption of retained oocytes. Moreover, in both sexes, a striking seasonal rhythm in the development of secondary sex characters has been found, together with dramatic growth of skeletal humeri and significant variation in serum calcium values (Cohen 1962a, b, 1963).Material digitalizado en SEDICI gracias a la colaboración del Dr. Jorge Williams (FCNM-UNLP).Facultad de Ciencias Naturales y Muse