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1.
An Acad Bras Cienc ; 94(2): e20190919, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35384963

RESUMO

The gametogenesis and reproduction of S. elegans from the São Francisco River at Três Marias, Minas Gerais, were analyzed in this study. Steindachrina elegans is a species abundant in the São Francisco River basin and an important fish in the food chain. The size at first gonadal maturation (indicated by the total length of the shortest spermatid male and spawned female) was 10.5 cm and 15.0 cm, respectively. Reproduction occurred more frequently from September to April. This period had high water temperature values. A high frequency of females was observed at the mature and spawned stages and height gonadosomatic index (GSI). Meanwhile, in males, the reproductive peak was from November to February. The long spawning period and the histological characteristics of the spawned ovaries that contained oocytes at different stages of development along with post-ovulatory and atretic oocytes indicates that the spawning of S. elegans is of the partial type.


Assuntos
Caraciformes , Reprodução , Animais , Brasil , Feminino , Gônadas , Masculino , Rios , Estações do Ano
2.
Ecotoxicol Environ Saf ; 224: 112670, 2021 Aug 18.
Artigo em Inglês | MEDLINE | ID: mdl-34418853

RESUMO

Bisphenol A (BPA) is an organic synthetic compound used in the plastic industry with endocrine disrupting activity. Although it is frequently found in surface waters, few studies have investigated its impact on fish gametogenesis, particularly when associated with natural stressors. In this regard, the present study evaluated BPA toxicity on spermatogenesis in the lambari Astyanax bimaculatus under controlled conditions and its interactive effects with water temperature. Adult specimens were exposed in duplicate to 40 µg/L and 400 µg/L BPA at 23 °C and 28 °C for 21 days; the control group did not receive BPA. Testicular samples were collected and analyzed using different cellular and molecular techniques. The results showed a significant reduction in the gonadosomatic index in the BPA-treated groups at both temperatures. A decrease in the testicular levels of 11-ketotestosterone was observed in the 400 µg/L BPA group at 23 °C, 17ß-estradiol increased significantly in the treated groups at 28 °C, and vitellogenin showed no difference between the treatments. The morphometric analysis of spermatogenesis revealed a significant increase in the proportion of spermatogonia, spermatocytes, and Sertoli cells in the treated groups, with a higher proportion at 23 °C than at 28 °C. Otherwise, the proportion of spermatozoa was significantly lower in the BPA-treated groups, with a greater reduction at 23 °C. In addition, BPA also stimulated spermatogonial proliferation in the treated groups, but apoptosis was significantly increased in spermatids at 23 °C. Testis-ova, cell degeneration, and chromatin alterations in spermatids and Sertoli cells were observed in the germinal epithelium of the BPA-treated groups. The integrated biomarker response (IBR) index revealed that the analyzed endpoints are suitable for assessing estrogenic contamination. Taken together, our results indicate that the interactive effects of BPA and temperature contribute to the impairment of spermatogenesis in A. bimaculatus with more severe effects observed on sperm production at 23 °C than at 28 °C.

3.
Fish Physiol Biochem ; 47(4): 797-810, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-33665751

RESUMO

In the last decades, oestrogenic compounds have often been reported in environmentally relevant concentrations in aquatic environments around the world. Most laboratory studies of oestrogens try to understand the effects of a single contaminant, but in natural environments, the effects may be quite different due to interactions with other compounds. The present study aimed to compare the action of oestrone (E1) and bisphenol-A (BPA), acting singularly and in combination, on the spermatogenesis of Astyanax bimaculatus. After exposure to 100 ng/L of E1, BPA and a mixture of the two for 15 days, our results showed that E1 and the E1 + BPA mixture significantly altered the number of spermatogenic cells. BPA presented high cytotoxicity when compared to other treatments. Analysis of the two oestrogenic compounds suggests that the E1 + BPA mixture has no additive or synergistic effects. Together, the results of the present study indicate that endocrine-disrupting chemicals (EDCs) analysed alone may behave differently than when administered with other substances.


Assuntos
Compostos Benzidrílicos/toxicidade , Characidae , Disruptores Endócrinos/toxicidade , Estrogênios/toxicidade , Estrona/toxicidade , Fenóis/toxicidade , Poluentes Químicos da Água/toxicidade , Animais , Apoptose/efeitos dos fármacos , Characidae/metabolismo , Estradiol/metabolismo , Receptor alfa de Estrogênio/metabolismo , Receptor beta de Estrogênio/metabolismo , Fígado/efeitos dos fármacos , Fígado/metabolismo , Fígado/patologia , Masculino , Reprodução/efeitos dos fármacos , Espermatozoides/efeitos dos fármacos , Testículo/efeitos dos fármacos , Testículo/patologia , Vitelogeninas/metabolismo
4.
Zygote ; 29(4): 270-275, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-33446289

RESUMO

Our study aimed to establish the response of Salminus franciscanus to hypophysation and describe the main morphological events of its embryonic process. Wild fish were captured in São Francisco River and selected broodstock (females: 66.4 ± 11.1 cm and 4.04 ± 2.32 kg; males: 58.3 ± 10.2 cm and 3.62 ± 1.12 kg) were kept at 26.1 ± 0.6°C for induction of final maturation/gamete release via the hypophysation technique. In females, two doses (0.8 and 5.6 mg/kg body weight) of crude pituitary extract of common carp (Cyprinus carpio) were administered with a 14 h interval. For males, a single dose (2.7 mg/kg body weight) of crude pituitary extract was applied at the same time as the females' second dose. Oocytes and sperm were manually stripped 8 h after a females' second hormonal dose. Fertilization was carried out using the dry method. Eggs were kept in funnel-type 60 L incubators at 24.3 ± 0.3°C and were analyzed and photographed every 10 min. After hormonal induction, 60% of females and 100% of males reacted positively and no broodstock mortality was recorded. The females released an average of 385.2 ± 78.4 g of oocytes and the fertilization rate observed was 50.4 ± 12.3%. The blastopore closure occurred at 7.5 h, somite formation at 12 h and hatching at 20 h post-fertilization. In general, the results of this study improve the understanding of the reproductive biology of dourado and confirm its potential for fish farming in the neotropical region.


Assuntos
Carpas , Caraciformes , Animais , Feminino , Masculino , Oócitos , Reprodução , Rios
5.
Neotrop. ichthyol ; 19(4): e200046, 2021. tab, graf, mapas
Artigo em Inglês | LILACS, VETINDEX | ID: biblio-1351155

RESUMO

River impoundments for electricity generation lead to environmental changes which severely affect fish migration and species richness. However, little is known about their effect on the genetic structure and population dynamics downstream from the reservoir. Here, we analyzed a set of ten microsatellite loci of Prochilodus lineatus, an important South American migratory fish. Specimens (n = 150) were sampled from five sites in a remnant lotic system that includes sections of the Grande, Pardo and Mogi Guaçu rivers, southeastern Brazil. The data showed that all microsatellites were polymorphic with the allele number per locus ranging from 5 to 32, and genetic diversity (H e ) varied from 0.74 to 0.80. Indices of genetic differentiation and Bayesian analysis showed a significant genetic structure and three genetic clusters inhabiting this river system. An asymmetric gene flow suggests source-sink metapopulation dynamics from tributaries (genetic source) to the main river (genetic sink). A genetic cluster that was not detected in the upper Mogi and Pardo rivers tributaries may indicate there is a "trapped gene pool" downstream from the Porto Colômbia dam. Thus, here we provide new insights into the genetic structure and population dynamics of a migratory fish species in a highly dammed river basin.(AU)


Represamento de rios para geração de eletricidade levam a mudanças ambientais que afetam severamente a migração de peixes e riqueza de espécies. No entanto, pouco se sabe sobre seu efeito na estrutura genética e dinâmica populacional a jusante de reservatórios. Aqui, analisamos um conjunto de dez loci de microssatélites de Prochilodus lineatus, um importante peixe migratório sul-americano. Os espécimes (n = 150) foram amostrados em cinco locais de um sistema lótico remanescente que inclui seções dos rios Grande, Pardo e Mogi Guaçu, sudeste do Brasil. Os dados mostraram que todos microssatélites eram polimórficos com o número de alelos por locus variando de 5 a 32 e diversidade genética (H e ) variou de 0,74 a 0,80. Índices de diferenciação genética e análise de agrupamento baseada em modelo bayesiano indicou a presença de três agrupamentos genéticos habitando este sistema fluvial. Um fluxo gênico assimétrico sugere dinâmica metapopulacional de fonte-sumidouro dos tributários (fonte genética) para o rio principal (sumidouro genético). Um agrupamento genético que não foi detectado nos tributários rio Mogi e rio Pardo parecem indicar que há um "trapped gene pool" a jusante da represa de Porto Colômbia. Assim, nós provemos aqui novos conhecimentos sobre a estrutura genética e dinâmica populacional de uma espécie de peixe migratório em um rio altamente fragmentado por barramentos.(AU)


Assuntos
Animais , Variação Genética , Reservatórios de Água , Repetições de Microssatélites , Estruturas Genéticas , Fluxo Gênico , Caraciformes , Teorema de Bayes
6.
Environ Monit Assess ; 192(8): 542, 2020 Jul 25.
Artigo em Inglês | MEDLINE | ID: mdl-32712724

RESUMO

Due to industrial, rural, and domestic waste disposal, heavy metals such as cadmium (Cd), chromium (Cr), lead (Pb), zinc (Zn), copper (Cu), and iron (Fe) continually infiltrate aquatic environments. These pollutants do not degrade naturally and, thus, have a high capacity for bioaccumulation in tissues and organs. The present study uses histological and immunohistochemical analyses to evaluate the contamination status of Salminus franciscanus, a large and economically important fish. Levels of Cd, Cr, Pb, Zn, Cu, and Fe were evaluated by atomic absorption spectrometry in the liver and muscle of fish sampled from two tributaries of the upper São Francisco River Basin, Brazil: the Abaeté and Paraopeba Rivers. In addition, histopathological alterations and expressions of three environmental biomarkers were assessed: metallothionein (MT), heat shock protein-70 (HSP70), and cytochrome P450-1A (CYP1A). The results show that fish from the Paraopeba River are unsuitable for human consumption, with several metals being detected above the safe limits established by the World Health Organization. Histopathological alterations in the liver and spleen were also significantly more frequent in fish from the Paraopeba River than in those from the Abaeté River (P < 0.05). Significant differences in the expressions of environmental biomarkers were observed between the rivers. Fish from the Abaeté River presented significantly higher values of the gonadosomatic index (GSI) and lower levels of metal contamination in the liver and muscle.


Assuntos
Metais Pesados/análise , Poluentes Químicos da Água/análise , Animais , Brasil , Monitoramento Ambiental , Humanos , Rios
7.
Reprod Fertil Dev ; 32(11): 988-998, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32693911

RESUMO

To support sperm production, fish testes undergo intense tissue remodelling, with endocrine, paracrine and autocrine signals regulating gonad physiology. The aim of this study was to investigate the testicular expression of insulin-like growth factor (Igf) 1 and Igf2 during spermatogenesis, and their relationship with cell proliferation and apoptosis throughout the reproductive cycle. The study was performed in male Hypostomus garmani, a catfish living in headwater rivers of the São Francisco River basin, Brazil. Spermatogenesis was analysed using histology, morphometry, immunohistochemistry and terminal deoxyribonucleotidyl transferase-mediated dUTP-digoxigenin nick end-labelling (TUNEL) analysis at different maturity stages. The results showed the proliferation of spermatogonia throughout the reproductive cycle, with a higher rate during the ripe stage. Germ and Sertoli cells expressed Igf1 at all stages of testicular maturity, Igf2 was predominant at the ripe stage and both Igf1 and Igf2 occurred at the spent stage. Caspase-3 and TUNEL analysis revealed a higher rate of apoptosis at the spent stage associated with reduced expression of Igf1 and Igf2. Sertoli cell proliferation was associated with spermatogonia and spermatocyte cysts at different stages of the reproductive cycle. Together, the data support a proliferative role for Igf1 and Igf2 in regulating testicular apoptosis in H. garmani, with cyclical variation in their expression during gonad maturation.


Assuntos
Apoptose/fisiologia , Peixes-Gato/metabolismo , Proliferação de Células/fisiologia , Fator de Crescimento Insulin-Like II/metabolismo , Fator de Crescimento Insulin-Like I/metabolismo , Espermatogênese/fisiologia , Espermatogônias/citologia , Animais , Peixes-Gato/genética , Fator de Crescimento Insulin-Like I/genética , Fator de Crescimento Insulin-Like II/genética , Masculino , Células de Sertoli/metabolismo , Espermatogônias/metabolismo , Testículo/metabolismo
8.
Anim Reprod Sci ; 213: 106272, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31987325

RESUMO

In Brazil, fishing in continental waters is prohibited from November to February, the rainy season, when most commercially important fish species are reproductively active. Brycon nattereri is a native species to the Paraná, Tocantins, and São Francisco River basins in Brazil and is on the national list of species threatened with extinction. The goal of this study was to analyse the main reproductive variables of B. nattereri from the Lourenço Velho River, located in the Paraná River basin, south-eastern Brazil. From 2013-2016, 326 specimens (156 females and 170 males) were caught bimonthly using gill nets. Biometric data, gonadosomatic index (GSI), and fecundity were determined for each specimen. The gonadal maturation stages and the breeding season were established. There were relatively greater GSI values for males and average values were similar to those of females, an uncommon feature in Neotropical freshwater fish. The greatest frequencies of mature fish occurred from April to July in the dry season, which is when there are least ambient temperatures. The fecundity for body weight varied from 16,300 to 62,800 oocytes per female and fully developed vitellogenic oocytes had a mean diameter of 1175 ± 278.87 µm. These results indicate that B. nattereri breeds in the dry season when the water temperature is colder and, therefore, protection from fishing of this species during this season needs to be established.


Assuntos
Characidae/fisiologia , Espécies em Perigo de Extinção , Reprodução/fisiologia , Distribuição Animal , Animais , Brasil , Comércio , Feminino , Masculino , Rios , Estações do Ano , Maturidade Sexual
9.
Ecotoxicol Environ Saf ; 190: 110165, 2020 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-31918258

RESUMO

Environmental disasters such as the rupturing of mine tailings dams are a major concern worldwide. In the present study, we assess the effects of the release of mine waste due to the rupture of the Fundão dam on two native fish species (Hoplias intermedius and Hypostomus affinis) from the Doce River basin. Two sampling sites were chosen: S1, a reference site, and S2, contaminated by mining waste. Water and sediment were collected to evaluate metals concentration. Adult fish were caught to analyse biological parameters, hepatic histopathology, and biomarkers of metal contamination. Compared to site S1, the concentration of manganese was statistically higher in water while lead, nickel, and arsenic were statistically higher in the sediment from site S2, and iron had no significant difference between sites. At site S1, fish of both species presented hepatic tissue with normal architecture. At site S2, hepatic alterations, such as cytoplasmic vacuolization and necrosis were frequently found in both species. Regarding the histopathological index, higher values were found in both species from site S2. The positive antibody reactions for cytochrome P450 1A (CYP1A) and metallothionein (MT) were statistically greater in site S2 for both species. The oxidative stress biomarkers, superoxide dismutase (SOD) and catalase (CAT) were statistically higher in H. intermedius from site S2, but only CAT was statistically greater in H. affinis at site S2. These results demonstrate that the release of mineral residues from the rupture of the Samarco mine dam is provoking hepatic damage in the fish from the Doce River besides inducing the expression of proteins and enzymes related to metal contamination.


Assuntos
Arsênio/toxicidade , Peixes-Gato/metabolismo , Caraciformes/metabolismo , Fígado/efeitos dos fármacos , Metais Pesados/toxicidade , Poluentes Químicos da Água/toxicidade , Animais , Arsênio/análise , Brasil , Catalase/metabolismo , Monitoramento Ambiental , Resíduos Industriais , Fígado/metabolismo , Fígado/patologia , Metais Pesados/análise , Mineração , Rios/química , Superóxido Dismutase/metabolismo , Poluentes Químicos da Água/análise
10.
Mol Cell Endocrinol ; 500: 110643, 2020 01 15.
Artigo em Inglês | MEDLINE | ID: mdl-31711986

RESUMO

Food restriction is part of the life cycle of many fish species; however, nutritional deficiency may negatively influence gametogenesis and gonadal maturation. The aim of this study was to evaluate the effects of food restriction on the spermatogenesis of Nile tilapia. For this, adult males were submitted to starvation and refeeding cycles (alternating periods of starvation and feeding) for 7, 14, 21, and 28 days. After 7 days of starvation, glycaemic and lipid levels were significantly reduced, followed by reduction of plasma testosterone (T) and 11-ketotestosterone (11-KT). In addition, reduced proliferation of spermatogonia and increased apoptosis of spermatocytes, spermatids, and spermatozoa was observed in starvation groups. In the refeeding groups, the sex steroids and the proportion of germ cells had no significant alterations compared to the control group, except for spermatozoa. In this sense, the present study suggests that starvation after 7 days progressively reduces T and 11-TK, resulting in damage to the production of spermatogenic cells, while refeeding may delay spermatogenesis but does not lead to testicular impairment.


Assuntos
Ciclídeos/fisiologia , Inanição/complicações , Testosterona/análogos & derivados , Testosterona/sangue , Ração Animal , Fenômenos Fisiológicos da Nutrição Animal , Animais , Proliferação de Células , Sobrevivência Celular , Ciclídeos/sangue , Índice Glicêmico , Metabolismo dos Lipídeos , Masculino , Espermatogênese
11.
Neotrop. ichthyol ; 18(4): e200091, 2020. tab, graf
Artigo em Inglês | LILACS, VETINDEX | ID: biblio-1143348

RESUMO

In this study, we determined the main reproductive parameters of piau gordura, Leporinus piau, in two sections of the São Francisco River basin. Between May 2015 and April 2016, a total of 573 specimens were captured from a lentic environment (section 1), the Três Marias Reservoir (TMR), and a lotic environment (section 2), downstream of the TMR at the confluence of the São Francisco River (SFR) with the Abaeté River. Analysis of reproductive activity showed that L. piau from both sections reproduced, but females and males from section 1 exhibited higher total length, body weight, Fulton condition factor, and gonadosomatic index values, as compared to section 2. Sexual dimorphism was evident in the species, with females being larger than males. Moreover, males reached first gonadal maturation at a smaller size than females. The peak maturation/mature stage was observed in November/April for females and males in section 1 and in November/December in section 2, coinciding with high temperatures and precipitation in the region. In both sections of the river, L. piau exhibited the typical characteristics of partial spawning, with a prolonged spawning period, and preferential reproduction in lentic environments.(AU)


Neste estudo, determinamos os principais parâmetros reprodutivos do piau gordura, Leporinus piau, em duas seções da bacia do rio São Francisco. Entre maio de 2015 e abril de 2016, um total de 573 espécimes foram capturados de um ambiente lêntico (seção 1), o reservatório de Três Marias (RTM), e um ambiente lótico (seção 2), à jusante da RTM na confluência do rio São Francisco (RSF) com o rio Abaeté. A análise da atividade reprodutiva mostrou que L. piau se reproduz nas duas seções, mas fêmeas e machos da seção 1 apresentaram maiores valores de comprimento total, peso corporal, fator de condição de Fulton e índice gonadossomático em comparação com a seção 2. O dimorfismo sexual foi evidente na espécie com as fêmeas sendo maiores do que os machos. Além disso, os machos atingiram a primeira maturação gonadal em tamanho menor do que as fêmeas. O pico do estágio de maturação/maduro foi observado em novembro/abril para fêmeas e machos na seção 1 e em novembro/dezembro na seção 2, coincidindo com altas temperaturas e precipitação na região. Em ambas as seções do rio, L. piau apresentou características típicas de desova parcelada com período de desova prolongada e reproduz preferencialmente em ambientes lênticos.(AU)


Assuntos
Animais , Reprodução , Peso Corporal , Anticoncepção/veterinária , Caraciformes/anatomia & histologia , Caraciformes/fisiologia , Caracteres Sexuais , Rios , Meio Ambiente
12.
Anim Reprod Sci ; 209: 106173, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31514919

RESUMO

The reproduction of Iheringichthys labrosus (Lütken, 1874) from the Turvo River, Brazil, was studied using anatomical, biometric, histological, and ultrastructural techniques. Between April 2014 and March 2015, a total of 278 males and 512 females were captured bimonthly. The testes of Iheringichthys labrosus are fringed and possess a cranial spermatogenic region and an exclusively secretory caudal region. Histologically, the cranial region is composed of seminiferous tubules with spermatogenesis being completed in cysts. The spermatozoa are of the primitive type with a spherical head and have a rudimentary intermediate piece and a long tail with an axonemic arrangement of 9 + 2. The caudal region does not form an individualized gland, and cells in this testis area have characteristics of protein secretion. A variable density electron-dense secretion accumulates in the cisternae of the rough endoplasmic reticulum in the lumen of the seminiferous tubules and in the testicular ducts during maturation. The cortical alveoli are discontinuous, and the zona pellucida consists of three layers crossed by pore canals, and the follicular cells are squamous in the early stages of oogenesis and cuboidal in advanced stages. The gonadosomatic index was associated with the maturation of the gonads while the condition factor indicated that the fish feed less and utilize adipose reserves during the reproductive period. Males and females reproductively functional throughout the year with spawning being partial or multiple, similar to that reported in studies of the species in lentic environments.


Assuntos
Peixes-Gato/fisiologia , Gônadas/anatomia & histologia , Gônadas/citologia , Reprodução/fisiologia , Animais , Peixes-Gato/anatomia & histologia , Tamanho Celular , Feminino , Gônadas/ultraestrutura , Masculino , Oogênese/fisiologia , Tamanho do Órgão , Ovário/anatomia & histologia , Ovário/citologia , Ovário/ultraestrutura , Estações do Ano , Espermatogênese/fisiologia , Espermatozoides/citologia , Espermatozoides/ultraestrutura , Temperatura , Testículo/citologia , Testículo/ultraestrutura
13.
Zygote ; 27(6): 375-381, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31405399

RESUMO

The present study evaluated the effects of low salinity on the early larval development of Oreochromis niloticus, specifically histological damage to white muscle, morphology of the yolk-sac surface and trunk area, and molecular expression of apoptosis and cell proliferation biomarkers. Newly hatched larvae were submitted to four salinity treatments for a period of 48 or 72 h, in duplicate: (S0) freshwater, (S2) 2 g l-1, (S4) 4 g l-1, and (S6) 6 g l-1NaCl. Larval development was examined using histology, electron microscopy, enzyme-linked immunosorbent assay (ELISA), and morphometry. At the yolk-sac surface, larvae of S4 and S6 displayed alterations to the apical opening of chloride cells that may be related to osmotic expenditure caused by the increased salinity. Caspase-3 expression did not differ significantly among treatments, however significantly lower proliferating cell nuclear antigen (PCNA) expression (P < 0.05) suggested minor cell proliferation in larvae of S4 and S6 compared with S0 and S2. Furthermore, there was a significant reduction in both trunk area and percentage of normal white muscle fibres (WF) in larvae of S4 and S6. Vacuolated areas and myofibrils concentrated at the cell periphery and found in the white muscle from larvae exposed to saline environments suggested disturbance to muscle development. Oedema and mononuclear infiltrate were also observed in the white muscle of S4 and S6 larvae. Together these results indicated that treatments with 4 and 6 g l-1 NaCl may cause osmoregulation expenditure, morphological alterations to the yolk-sac surface and histological damage to skeletal muscle that negatively affected the early larval development of O. niloticus.


Assuntos
Ciclídeos/crescimento & desenvolvimento , Larva/efeitos dos fármacos , Salinidade , Cloreto de Sódio/farmacologia , Animais , Apoptose/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Água Doce , Brânquias/citologia , Brânquias/efeitos dos fármacos , Brânquias/crescimento & desenvolvimento , Larva/crescimento & desenvolvimento , Larva/ultraestrutura , Microscopia Eletrônica , Músculo Esquelético/citologia , Músculo Esquelético/efeitos dos fármacos , Músculo Esquelético/crescimento & desenvolvimento , Osmorregulação/efeitos dos fármacos
14.
Mol Reprod Dev ; 86(11): 1592-1602, 2019 11.
Artigo em Inglês | MEDLINE | ID: mdl-31355486

RESUMO

Follicular atresia is a hormonally controlled degenerative process involving apoptosis of the somatic and germ cells. Since different signaling pathways can induce cell death, the aim of the present study was to investigate cell death signaling and crosstalk between autophagic, apoptotic, and lysosomal proteins during follicular atresia in Nile tilapia. For this, females were kept in controlled conditions for 21 days, and ovary samples were collected weekly. The atretic follicles (AF) were analyzed in three regression phases: Early, advanced, and late. Under electron microscopy, the follicular cells exhibited numerous protein synthesis organelles in the early AF. Immunoreactivity for Bcl2, Beclin1, Lc3, and Cathepsin D increased significantly in advanced AF (p < .001), when follicular cells were in intense yolk phagocytosis. In this phase, autophagosomes and autolysosomes were frequently observed. In the late AF, follicular cells had a markedly electron-lucid cytoplasm and immunoreactivity for Bax and TUNEL assay indicated an elevated apoptosis rate. Colocalisation of Lamp1/Cathepsin D and Lc3/Caspase-3 suggests dynamic crosstalk between the autophagy, apoptosis, and lysosome pathways. Taken together, the data indicate that autophagy plays a role in the homeostasis and clearance of the follicular cells preceding Cathepsin D mediated apoptosis during follicular atresia in Nile tilapia.


Assuntos
Apoptose , Catepsina D/metabolismo , Proteínas de Peixes/metabolismo , Atresia Folicular/metabolismo , Folículo Ovariano/enzimologia , Tilápia/metabolismo , Animais , Feminino
15.
Reprod Fertil Dev ; 31(10): 1637-1646, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31097079

RESUMO

Sexual differentiation and early gonadal development are critical events in vertebrate reproduction. In this study, the initial testis development and expression of the Vasa, Nanos2 and Sox9 proteins were examined in Nile tilapia Oreochromis niloticus submitted to induced sex reversal. To that end, 150O. niloticus larvae at 5 days post-hatching (dph) were kept in nurseries with no hormonal addition (control group) and 150 larvae were kept with feed containing 17α-methyltestosterone to induce male sex reversal (treated group). Morphological sexual differentiation of Nile tilapia occurred between 21 and 25 dph and sex reversal resulted in 94% males, whereas the control group presented 53% males. During sexual differentiation, gonocytes (Gon) were the predominant germ cells, which decreased and disappeared after that stage in both groups. Undifferentiated spermatogonia (Aund) were identified at 21 dph in the control group and at 23 dph in the treated group. Differentiated spermatogonia (Adiff) were found at 23 dph in both groups. Vasa and Nanos2 occurred in Gon, Aund and Adiff and there were no significant differences between groups. Vasa-labelled Adiff increased at 50 dph in both groups and Nanos2 presented a high proportion of labelled germ cells during sampling. Sertoli cells expressed Sox9 throughout the experiment and its expression was significantly greater during sexual differentiation in the control group. The results indicate that hormonal treatment did not alter initial testis development and expression of Vasa and Nanos2 in Nile tilapia, although lower expression of Sox9 and a delay in sexual differentiation was detected in the treated group.


Assuntos
Ciclídeos/genética , RNA Helicases DEAD-box/genética , Transtornos do Desenvolvimento Sexual/genética , Proteínas de Ligação a RNA/genética , Fatores de Transcrição SOX9/genética , Testículo/crescimento & desenvolvimento , Animais , Diferenciação Celular/genética , Ciclídeos/crescimento & desenvolvimento , RNA Helicases DEAD-box/metabolismo , Transtornos do Desenvolvimento Sexual/metabolismo , Transtornos do Desenvolvimento Sexual/veterinária , Feminino , Regulação da Expressão Gênica no Desenvolvimento , Gônadas/crescimento & desenvolvimento , Gônadas/metabolismo , Masculino , Proteínas de Ligação a RNA/metabolismo , Fatores de Transcrição SOX9/metabolismo , Diferenciação Sexual/genética , Testículo/metabolismo
16.
Sci Rep ; 9(1): 4333, 2019 03 13.
Artigo em Inglês | MEDLINE | ID: mdl-30867523

RESUMO

Despite its relevance for ecology, evolution and conservation of species, natural hybridization and hybrids biology are still poorly studied in freshwater fish. Here, we tested the hypothesis that sympatric species Astyanax paranae and A. fasciatus are able to interbreed in the natural environment and presented evidence for the first record of hybridization between these species. We analyzed anatomical traits, gametogenesis, reproductive biology, and genetic variations of the COI and S7 genes of both species and putative hybrids. Intermediate morphometric and meristic features were observed in hybrids when compared to A. paranae and A. fasciatus. Overlap in reproductive season was showed for these species, with greater reproductive activity from August to January, but hybrids did not present any sign of gonadal maturation. Oogonia and perinucleolar follicles as well as spermatogonia and primary spermatocytes were found in hybrids, but previtellogenic and vitellogenic follicles, spermatids, and spermatozoa were absent. Moreover, several alterations in gametogenesis were detected, such as interrupted meiosis in both males and females, vacuolated and degenerated germ cells, increased interstitial tissue, and presence of immune cells. Molecular analyses supported the hypothesis of hybridization between A. paranae and A. fasciatus. Overall, our multidisciplinary approach also provides strong evidence that hybrids are infertile.


Assuntos
Characidae/genética , Hibridização Genética , Infertilidade , Simpatria , Animais , Characidae/fisiologia , Feminino , Haplótipos , Masculino , Reprodução
17.
Theriogenology ; 131: 1-8, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-30921633

RESUMO

Continental waters salinisation is a global threat that has grown because of climate change and human activities, but little is known about how and what biological tracts are affected. The aim of this study was to investigate the influence of different water salinities on the expression of HSP70, PCNA and caspase-3 during spermatogenesis of Nile tilapia. Adult males were submitted to four salinity treatments: (S0) fresh water, (S7) 7 g L-1, (S14) 14 g L-1, and (S21) 21 g L-1 for 1, 4, and 9 days. All specimens were in spermatogenic activity and the highest values of the gonadosomatic index (GSI) occurred in the S0 and S7. In the morphometric analysis, spermatocytes were the most frequent germ cell detected in all treatments (>50%) and spermatids achieved about 20% of the testicular proportion, with few variations among treatments. Spermatozoa were significantly reduced only in S14 compared to S7. Leydig cells were significantly increased in S14 when compared to S7 but plasma concentrations of 11-KT showed no significant difference among treatments. ELISA assay showed higher testicular expression of HSP70 at 1 day in all groups, followed by a significant decrease at days 4 and 9 in S14 and S21. The expression of PCNA was significantly lower while the activity of caspase-3 was higher in S14 and S21 when compared to S0 and S7. These results indicate that higher salinities in S14 and S21 interfere with the relationship between testicular HSP70, PCNA, and caspase-3, but with few effects over spermatogenesis dynamics of Nile tilapia.


Assuntos
Salinidade , Espermatogênese/fisiologia , Testículo/efeitos dos fármacos , Tilápia/fisiologia , Animais , Caspase 3/metabolismo , Mudança Climática , Ensaio de Imunoadsorção Enzimática , Proteínas de Peixes/metabolismo , Proteínas de Choque Térmico HSP72/metabolismo , Masculino , Antígeno Nuclear de Célula em Proliferação/metabolismo , Testículo/metabolismo , Testículo/fisiologia , Testosterona/análogos & derivados , Testosterona/sangue , Tilápia/metabolismo
18.
Gen Comp Endocrinol ; 279: 99-108, 2019 08 01.
Artigo em Inglês | MEDLINE | ID: mdl-30605662

RESUMO

Discharge of municipal wastewater promotes the entry of diverse oestrogenic compounds into the water bodies. This complex mixture of substances interferes in the steroidogenic pathway, being able to promote severe reproductive impairment in freshwater fish populations. The purpose of the present study was to evaluate the effects of oestrogenic endocrine disruptors (EDCs) mixture on gonadal sex steroids (testosterone, T; 11-ketotestosterone, 11-KT; 17ß-oestradiol, E2; 17-hydroxyprogesterone, 17-OHP) in the peak of the reproductive season of Astyanax rivularis, correlating the results obtained with the proportion of germ cells and gonadal histopathology. Three sampling sites were chosen to conduct the study, one reference site (S1), without contamination by municipal wastewater and two sites (S2 and S3) receiving discharge of municipal wastewater. Males of A. rivularis presented higher concentrations of E2, lower androgens (T and 11-KT) in gonads when compared to males from site S1. Concentrations of 17-OHP did not present significant difference among sites. In sites S2 and S3, the proportion of early spermatocytes, spermatids and Leydig cells increased while spermatozoa decreased compared to fish from S1. The following gonadal histopathologies were detected in the male fishes: intersex gonads (28% in S3) and testicular degeneration with germinal epithelium exhibiting agglutinated germ cells masses and empty cysts (57% in S2 and 71% in S3). In females, concentrations of T, E2 and 17-OHP did not present significant difference among the sites, however higher 11-KT concentrations were detected in females from sites S2 and S3. A lower proportion of perinucleolar follicles and a higher incidence of vitellogenic follicles, besides, aged oocytes and the presence of eosinophilic proteinaceous fluid in the interstitial compartment were also found in females from impacted sites. These results indicate that the urbanization and consequent release of municipal wastewater containing oestrogenic compounds in the headwater creeks are altering the levels of sex hormones and gametogenesis of A. rivularis. Further studies should be performed to determine whether oestrogenic endocrine disrupters are disrupting the reproduction of A. rivularis.


Assuntos
Characidae/fisiologia , Disruptores Endócrinos/toxicidade , Exposição Ambiental , Gametogênese/efeitos dos fármacos , Hormônios Esteroides Gonadais/metabolismo , Clima Tropical , Animais , Estradiol/farmacologia , Feminino , Geografia , Masculino , Folículo Ovariano/efeitos dos fármacos , Folículo Ovariano/metabolismo , Testículo/efeitos dos fármacos , Poluentes Químicos da Água/toxicidade , Qualidade da Água
19.
Reprod Fertil Dev ; 31(3): 547-556, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30373705

RESUMO

Fish embryos are particularly vulnerable to temperature changes, with the effects varying with developmental stage. The major aim of the present study was to analyse the relationship between apoptosis and heat shock protein (HSP) 70 during embryo development under thermal stress conditions. To this end, Prochilodus lineatus embryos at the blastopore closure stage were subjected to one of three thermal treatments for 1h (Group 1, 25°C (control); Group 2, 20°C; Group 3, 30°C) and then examined at 0, 4 and 8h posttreatment (h.p.t.). The viability of embryos was highest in Group 1 (81.33±16.65%), followed by Group 3 and Group 2 (75.33±12.10% and 68.67±16.86% respectively), with significant difference between Groups 1 and 2 (P<0.05). At 0h.p.t., embryos subjected to thermal stress (Group 3) had a significantly higher number of terminal deoxyribonucleotidyl transferase-mediated dUTP-digoxigenin nick end-labelling (TUNEL)- and caspase-3-labelled cells, and a lower number of HSP70-positive cells than those in the control group. At 4h.p.t., there was a decrease in the TUNEL reaction and an increase in HSP70 in embryos in Group 3. At 8h.p.t., the size of Group 3 embryos was significantly smaller than that of Group 1 embryos. The results indicate a cytoprotective role for HSP70, regulating caspase-3-mediated apoptosis during embryo development of P. lineatus; however, this mechanism is not effective in controlling embryo viability and larval malformations.


Assuntos
Apoptose/fisiologia , Blastocisto/metabolismo , Desenvolvimento Embrionário/fisiologia , Proteínas de Choque Térmico HSP70/metabolismo , Resposta ao Choque Térmico/fisiologia , Animais , Caspase 3/metabolismo , Caraciformes , Temperatura Alta
20.
Fish Physiol Biochem ; 45(1): 167-176, 2019 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-30143929

RESUMO

The insulin-like growth factor (IGF) system plays important roles in fish reproduction, but the expression pattern and cellular location of IGF-I and IGF-II during gonadal maturation are uncertain. The present study reports a stage-specific assessment of gonadal expression levels and immunolocalisation of IGF-I and IGF-II in Astyanax fasciatus, a characid fish from South America. Adult fish in different maturity stages were caught in the Furnas Reservoir, Grande River, Brazil. Gonad samples were processed for histology, immunohistochemistry, and ELISA for IGF-I and IGF-II. Ovarian levels of IGF-I were low during ripening and ripe stages, higher in totally spent, and then decreased in resting. Levels of IGF-II increased during ovarian maturation, reaching significantly higher values at stage totally spent. In males, IGF-I levels followed gonadal maturation, with higher values in ripening and ripe stages, whereas IGF-II levels showed higher values in stage ripening and partially spent. A positive correlation was found between IGF-I and gonadosomatic index (GSI) for males (r = 0.59), while females showed a negative correlation (r = - 0.43), but IGF-II showed no correlation to GSI. IGF-I was expressed mainly in oogonia nests whereas IGF-II stained the follicular cells in the perinucleolar follicles, cortical vesicles in the previtellogenic follicles, and oogonia nests. In males, IGF-I was evident in spermatogonia and spermatocytes while IGF-II stained Sertoli cells surrounding spermatids cysts and spermatogonia in late stages. Together, these findings support a hypothesis that the balance between IGF-I and IGF-II levels is important in the regulation of gonad maturation in Astyanax fasciatus.


Assuntos
Characidae/fisiologia , Fator de Crescimento Insulin-Like II/metabolismo , Fator de Crescimento Insulin-Like I/metabolismo , Ovário/metabolismo , Testículo/metabolismo , Animais , Feminino , Regulação da Expressão Gênica no Desenvolvimento , Genes Controladores do Desenvolvimento , Imuno-Histoquímica/veterinária , Fator de Crescimento Insulin-Like I/genética , Fator de Crescimento Insulin-Like II/genética , Masculino , Ovário/crescimento & desenvolvimento , Testículo/crescimento & desenvolvimento
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