RESUMO

Mitochondrial adrenodoxins (ADXs) are small iron-sulfur proteins with electron transfer properties. In animals, ADXs transfer electrons between an adrenodoxin reductase (ADXR) and mitochondrial P450s, which is crucial for steroidogenesis. Here we show that a plant mitochondrial steroidogenic pathway, dependent on an ADXR-ADX-P450 shuttle, is essential for female gametogenesis and early embryogenesis through a maternal effect. The steroid profile of maternal and gametophytic tissues of wild-type (WT) and adxr ovules revealed that homocastasterone is the main steroid present in WT gametophytes and that its levels are reduced in the mutant ovules. The application of exogenous homocastasterone partially rescued adxr and P450 mutant phenotypes, indicating that gametophytic homocastasterone biosynthesis is affected in the mutants and that a deficiency of this hormone causes the phenotypic alterations observed. These findings also suggest not only a remarkable similarity between steroid biosynthetic pathways in plants and animals but also a common function during sexual reproduction.

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RESUMO

As serpentes pertencem ao segundo maior grupo dentro dos répteis, podendo apresentar sazonalidade quanto à espermatogênese, com produção descontínua ou contínua. O presente trabalho tem como objetivo caracterizar aspectos da biologia reprodutiva de Boa constrictor constrictor com base nos achados histológicos dos testículos nos períodos de máxima atividade (período de gametogênese) e quiescência. Os testículos de dois espécimes de Boa c. constrictor (7767 e 11752) foram cortados a uma espessura de 3µm em micrótomo, corados com azul de toluidina 1%, fotodocumentados e descritos. A presença de espermatozoides na luz do túbulo seminífero no indivíduo 7767 indica um período de máxima gametogênese, enquanto o lúmen dos túbulos seminíferos pouco evidentes, sem a presença de espermatozoides e de células gaméticas em divisão, caracteriza o indivíduo 11752 em período quiescente. Mediante os achados histológicos descritos no presente estudo, concluiu-se que Boa c. constrictor apresenta sazonalidade em relação à gametogênese, sendo esse padrão de sazonalidade associado ao período de cópulas relatado em literatura característico de serpentes com padrão pré-nupcial.(AU)

These snakes belong to the second largest group within the reptiles, being able to present seasonality regarding spermatogenesis, with discontinuous or continuous production. The present study aims to characterize Boa constrictor constrictor reproductive biology aspects from histological findings in testicles during periods of maximum activity (period of gametogenesis) and quiescence. The testicles of two specimens of Boa c. constrictor (7767 and 11752) were cut to a thickness of 3µm in microtome, stained with 1% toluidine blue, photodocumented and described. The spermatozoa presence in the seminiferous tubule lumen in individual 7767 indicates a period of maximum gametogenesis, whereas the seminiferous tubules lumen is not very evident without spermatozoa and the absence of dividing gametic cells characterizes individual 11752 in the quiescent period. Through the histological findings we concluded that Boa c. constrictor presents seasonality in relation to gametogenesis, and the pattern of reproductive seasonality observed along with the period of copulas reported in the literature resembles the pre-nuptial pattern.(AU)

Assuntos

RESUMO

As serpentes pertencem ao segundo maior grupo dentro dos répteis, podendo apresentar sazonalidade quanto à espermatogênese, com produção descontínua ou contínua. O presente trabalho tem como objetivo caracterizar aspectos da biologia reprodutiva de Boa constrictor constrictor com base nos achados histológicos dos testículos nos períodos de máxima atividade (período de gametogênese) e quiescência. Os testículos de dois espécimes de Boa c. constrictor (7767 e 11752) foram cortados a uma espessura de 3µm em micrótomo, corados com azul de toluidina 1%, fotodocumentados e descritos. A presença de espermatozoides na luz do túbulo seminífero no indivíduo 7767 indica um período de máxima gametogênese, enquanto o lúmen dos túbulos seminíferos pouco evidentes, sem a presença de espermatozoides e de células gaméticas em divisão, caracteriza o indivíduo 11752 em período quiescente. Mediante os achados histológicos descritos no presente estudo, concluiu-se que Boa c. constrictor apresenta sazonalidade em relação à gametogênese, sendo esse padrão de sazonalidade associado ao período de cópulas relatado em literatura característico de serpentes com padrão pré-nupcial.(AU)

These snakes belong to the second largest group within the reptiles, being able to present seasonality regarding spermatogenesis, with discontinuous or continuous production. The present study aims to characterize Boa constrictor constrictor reproductive biology aspects from histological findings in testicles during periods of maximum activity (period of gametogenesis) and quiescence. The testicles of two specimens of Boa c. constrictor (7767 and 11752) were cut to a thickness of 3µm in microtome, stained with 1% toluidine blue, photodocumented and described. The spermatozoa presence in the seminiferous tubule lumen in individual 7767 indicates a period of maximum gametogenesis, whereas the seminiferous tubules lumen is not very evident without spermatozoa and the absence of dividing gametic cells characterizes individual 11752 in the quiescent period. Through the histological findings we concluded that Boa c. constrictor presents seasonality in relation to gametogenesis, and the pattern of reproductive seasonality observed along with the period of copulas reported in the literature resembles the pre-nuptial pattern.(AU)

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RESUMO

Abstract The objectives of the present study is to describe the size for exploitation and gonadal maturation of L. pectinata in Peças Island in Paraná coast. Twenty two individuals were sampled every month, from an intertidal flat of the Peças River, Municipality of Guaraqueçaba, during two periods – summer/autumn and winter of the 2009. Environmental parameter data was obtained at the same time of the biological sampling: temperature, salinity and seawater transparency at the Peças River mouth. The animals’ height, length, width, gross weight, wet weight of meat and dry weight of meat were measured at the lab. The gonad development stages (GDS), condition index (CI) and yield index (Y) were calculated. Sex identification was conducted by direct observation of the gonads and gametes under an optic microscope. Individuals were classified as males (M), females (F) or undetermined (U). The medium height observed was of 49.62 ± 6.84 mm. Period of more expressive gonad repletion were observed in summer when water temperature was higher. Results of GDS in both periods showed a predominance of partially filled gonad stages. This may be related with the fact that L. pectinata has intense gametogenesis activity, that is, the organisms do not have a resting interval, but go back to gonad restructuring rapidly after releasing the gametes. The continuity of the reproductive cycle of the specimens found in both studied periods could demonstrate a possible continuous reproduction of the species and a size for exploitation above 40.00 mm of height.

Resumo O presente estudo tem como objetivo descrever o tamanho de exploração e a maturação gonadal de L. pectinata na Ilha das Peças no litoral do Paraná. Vinte e dois indivíduos foram amostrados mensalmente na região entre-marés no Rio das Peças, Município de Guaraqueçaba, durante 2 períodos – verão/outono e inverno de 2009. Paralelamente às amostragens, foram obtidos dados dos parâmetros ambientais: temperatura, salinidade e transparência da água do mar na foz do Rio das Peças. A altura, comprimento, largura, peso bruto, peso úmido da carne e peso seco da carne dos animais foram medidos no laboratório. Foram calculados os estágios de desenvolvimento gonadal (EDG), índices de condição (IC) e de rendimento (R). A Identificação do sexo foi realizada por observação direta das gônadas e gametas sob microscópio óptico. Os indivíduos foram classificados como: machos (M), fêmeas (F) ou indeterminados (I). A altura média observada foi de 49,62 ± 6,84 mm. O período de maior repleção gonadal foi observado no verão, quando a temperatura da água foi mais elevada. Resultados dos EDG em ambos os períodos mostrou um predomínio de gônadas parcialmente cheias. Isso pode estar relacionado com o fato de que L. pectinata tem atividade gametogênese intensa, ou seja, os organismos não têm um intervalo de repouso, mas voltam a reestruturação das gônadas rapidamente após liberação dos gametas. A continuidade do ciclo reprodutivo dos espécimes encontrados em ambos os períodos estudados, pode demonstrar possível reprodução contínua da espécie e tamanho de exploração superior a 40,00 mm de altura.

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RESUMO

The objectives of the present study is to describe the size for exploitation and gonadal maturation of L. pectinata in Peças Island in Paraná coast. Twenty two individuals were sampled every month, from an intertidal flat of the Peças River, Municipality of Guaraqueçaba, during two periods - summer/autumn and winter of the 2009. Environmental parameter data was obtained at the same time of the biological sampling: temperature, salinity and seawater transparency at the Peças River mouth. The animals' height, length, width, gross weight, wet weight of meat and dry weight of meat were measured at the lab. The gonad development stages (GDS), condition index (CI) and yield index (Y) were calculated. Sex identification was conducted by direct observation of the gonads and gametes under an optic microscope. Individuals were classified as males (M), females (F) or undetermined (U). The medium height observed was of 49.62 ± 6.84 mm. Period of more expressive gonad repletion were observed in summer when water temperature was higher. Results of GDS in both periods showed a predominance of partially filled gonad stages. This may be related with the fact that L. pectinata has intense gametogenesis activity, that is, the organisms do not have a resting interval, but go back to gonad restructuring rapidly after releasing the gametes. The continuity of the reproductive cycle of the specimens found in both studied periods could demonstrate a possible continuous reproduction of the species and a size for exploitation above 40.00 mm of height.

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RESUMO

Macroalgae and filamentous turf algae (FTA) are abundant on degraded coral reefs, and the reproductive responses of corals may indicate sub-lethal stress under these conditions. The percentage of gametogenic stages (PGS) and the maximum diameter of eggs (MDE; or egg size) of Orbicella annularis were used to evaluate the effect of long- (7-10 months) and short-term (2.5 months) FTA removal (treatments T1 and T2, respectively) at both the beginning (May) and the end (August) of gametogenesis. Ramets (individual lobes of a colony) surrounded by FTA (T3) or crustose coralline algae (CCA; T4) were used as controls. The removal of FTA enhanced the development of gametes (i.e., a larger and higher percentage of mature gametes (PMG)) of O. annularis for T1 vs. T3 ramets in May and T1 and T2 vs. T3 ramets in August. Similar values of PGS and MDE between gametes from T3 and T4 in both May and August were unexpected because a previous study had shown that the same ramets of T4 (with higher tissue thickness, chlorophyll a cm-2 and zooxanthellae density and lower mitotic index values) were less stressed than ramets of T3. Evaluating coral stress through reproduction can reveal more sensitive responses than other biological parameters; within reproductive metrics, PGS can be a better stress indicator than egg size. The presence of turf algae strongly impacted the development of gametes and egg size (e.g., PMG in ramets with FTA removal increased almost twofold in comparison with ramets surrounded by FTA in August), most likely exerting negative chronic effects in the long run due to the ubiquity and permanence of turf algae in the Caribbean. These algae can be considered a stressor that affects coral sexual reproduction. Although the effects of turf algae on O. annularis are apparently less severe than those of other stressors, the future of this species is uncertain because of the combined impacts of these effects, the decline of O. annularis populations and the almost complete lack of recruitment.

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Despite the great advances in sequencing technologies, genomic and transcriptomic information for marine non-model species with ecological, evolutionary, and economical interest is still scarce. In this work we aimed to identify genes expressed during spermatogenesis in the functional hermaphrodite scallop Nodipecten subnodosus (Mollusca: Bivalvia: Pectinidae), with the purpose of obtaining a panel of genes that would allow for the study of differentially transcribed genes between diploid and triploid scallops in the context of meiotic arrest and reproductive sterility. Because our aim was to isolate genes involved in meiosis and other testis maturation-related processes, we generated suppressive subtractive hybridization libraries of testis vs. inactive gonad. We obtained 352 and 177 ESTs by clone sequencing, and using pyrosequencing (454-Roche) we maximized the identified ESTs to 34,276 reads. A total of 1,153 genes from the testis library had a blastx hit and GO annotation, including genes specific for meiosis, spermatogenesis, sex-differentiation, and transposable elements. Some of the identified meiosis genes function in chromosome pairing (scp2, scp3), recombination and DNA repair (dmc1, rad51, ccnb1ip1/hei10), and meiotic checkpoints (rad1, hormad1, dtl/cdt2). Gene expression analyses in different gametogenic stages in both sexual regions of the gonad of meiosis genes confirmed that the expression was specific or increased towards the maturing testis. Spermatogenesis genes included known testis-specific ones (kelch-10, shippo1, adad1), with some of these known to be associated to sterility. Sex differentiation genes included one of the most conserved genes at the bottom of the sex-determination cascade (dmrt1). Transcript from transposable elements, reverse transcriptase, and transposases in this library evidenced that transposition is an active process during spermatogenesis in N. subnodosus. In relation to the inactive library, we identified 833 transcripts with functional annotation related to activation of the transcription and translation machinery, as well as to germline control and maintenance.

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RESUMO

Na maioria dos peixes Teleostei, a gametogênese é um evento cíclico e sazonal. A renovação dos gametas, seu desenvolvimento, diferenciação, maturação e liberação provocam várias alterações nas características das gônadas ao longo dos ciclos reprodutivos anuais. Essas alterações são utilizadas para reconhecer fases nos ciclos reprodutivos. O reconhecimento dessas fases constitui um dos parâmetros aplicados na gestão dos recursos pesqueiros. Este trabalho apresenta uma recente proposta de reconhecimento das fases reprodutivas desenvolvida para os Perciformes adaptada para os Ostariophysi neotropicais (Siluriformes e Characiformes). Soma-se a isso uma breve descrição da gametogênese nos peixes Teleostei. (AU)

In most of Teleostei fish gametogenesis is a cyclical and seasonal event. The renewal of the gametes, their development, differentiation, maturation and release provoke many alterations of gonadal features along the annual reproductive cycles. These alterations are used to recognize phases of the reproductive cycles. The recognition of these phases constitutes one of the parameters applied to the management of fisheries resources. Herein a recent proposal of the recognition of the reproductive phases in the Perciformes is exposed and its adaptation to the Neotropical Ostariophysi (Siluriformes and Characiformes) is provided. In addition, the gametogenesis in the Teleostei fish is briefly described.(AU)

Assuntos

RESUMO

Na maioria dos peixes Teleostei, a gametogênese é um evento cíclico e sazonal. A renovação dos gametas, seu desenvolvimento, diferenciação, maturação e liberação provocam várias alterações nas características das gônadas ao longo dos ciclos reprodutivos anuais. Essas alterações são utilizadas para reconhecer fases nos ciclos reprodutivos. O reconhecimento dessas fases constitui um dos parâmetros aplicados na gestão dos recursos pesqueiros. Este trabalho apresenta uma recente proposta de reconhecimento das fases reprodutivas desenvolvida para os Perciformes adaptada para os Ostariophysi neotropicais (Siluriformes e Characiformes). Soma-se a isso uma breve descrição da gametogênese nos peixes Teleostei.

In most of Teleostei fish gametogenesis is a cyclical and seasonal event. The renewal of the gametes, their development, differentiation, maturation and release provoke many alterations of gonadal features along the annual reproductive cycles. These alterations are used to recognize phases of the reproductive cycles. The recognition of these phases constitutes one of the parameters applied to the management of fisheries resources. Herein a recent proposal of the recognition of the reproductive phases in the Perciformes is exposed and its adaptation to the Neotropical Ostariophysi (Siluriformes and Characiformes) is provided. In addition, the gametogenesis in the Teleostei fish is briefly described.

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RESUMO

Melampus coffeus belongs to a primitive group of pulmonate mollusks found mainly in the upper levels of the marine intertidal zone. They are common in the neotropical mangroves. Little is known about the biology of this species, particularly about its reproduction. The aim of this study was to 1) characterize the morphology and histology of M. coffeus' gonad; 2) describe the main gametogenesis events and link them to a range of maturity stages; 3) chronologically evaluate the frequency of the different maturity stages and their relation to environmental factors such as water, air and sediment temperatures, relative humidity, salinity and rainfall; and 4) characterize M. coffeus' spawning, eggs and newly hatched veliger larvae. Samples were collected monthly between February, 2007 and January, 2009 from the mangroves of Praia de Arpoeiras, Acaraú County, State of Ceará, northeastern Brazil. The characterization of the gonad development stages was carried out using routine histological techniques. The results of this study show that Melampus coffeus is a simultaneous hermaphrodite. The follicles have masculine and feminine elements, interleaved within the gonad. M. coffeus presents a well-defined synchronous reproductive cycle, showing successive maturation, release and resting periods. The average diameter of the oocytes was negatively correlated with salinity and positively correlated with rainfall. The results show that no reproductive activity occurs during periods of drought. After the dry season, the increasing rainfall levels and reduced salinity lead to the appearance of very dense populations, predominantly composed of small individuals.

Melampus coffeus encontra-se em um grupo primitivo de moluscos pulmonados, primordialmente marinhos, habitantes dos níveis superiores da zona entremarés, comum em manguezais do Oceano Atlântico. Pouco se sabe sobre a biologia da espécie, em especial, sobre a sua reprodução. Os objetivos deste trabalho foram: 1) caracterizar morfo-histologicamente a gônada de M. coffeus; 2) descrever os principais eventos da gametogênese e associá-los a uma escala de estágios de maturidade; 3) avaliar temporalmente a frequência dos estágios de maturidade e sua possível relação com os fatores ambientais, como a temperatura da água, do ar e do sedimento, a umidade relativa, a salinidade e a pluviosidade, e 4) caracterizar a postura, os ovos e a véliger recém-eclodida de M. coffeus. Foram realizadas coletas mensais de fevereiro de 2007 a janeiro de 2009, no manguezal da Praia de Arpoeiras, município de Acaraú-Ceará, na Região Nordeste do Brasil. A caracterização das fases de desenvolvimento da gônada foi realizada utilizando-se técnicas histológicas de rotina. Os resultados deste estudo mostram que Melampus coffeus é um hermafrodita simultâneo. Os folículos apresentam elementos masculinos e femininos, distribuindo-se na gônada intercalados radialmente. M. coffeus apresenta um ciclo reprodutivo sincrônico bem definido, evidenciando-se períodos sucessivos de amadurecimento, de liberação e de repouso. O diâmetro médio dos oócitos apresentou correlação negativa com a salinidade e positiva com a pluviosidade. Os resultados indicam que, nos períodos de estiagem, não há atividade reprodutiva. Após essa estação, quando os valores de pluviosidade aumentam e a salinidade diminui, as populações são bastante densas e predominam indivíduos pequenos.

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