Sample records for gametogenesis
from WorldWideScience.org

Sample records 1 - 4 shown.



1

Gametogênese e dinâmica da reprodução de Anodontites trapesialis (Lamarck) (Unionoida, Mycetopodidae) no lago Baía do Poço, planície de inundação do rio Cuiabá, Mato Grosso, Brasil/ Gametogenesis and dynamics of the reproduction of Anodontites trapesialis (Lamarck) (Unionoida, Mycetopodidae) from Baia do Poço Lake at the Cuiabá River wetland, Mato Grosso, Brazil

Callil, Cláudia T.; Mansur, Maria C. D.
2007-01-01

Resumo em português O ciclo reprodutivo de Anodontites trapesialis foi estudado entre os meses de maio de 1998 a abril de 1999. Análises quantitativas dos elementos celulares revelaram que a espécie é exclusivamente hermafrodita com folículos masculinos e femininos separados. A gametogênese é contínua com picos de maturação e eliminação de gametas durante a estação seca. A ovogênese tem seu período de maturação máxima em abril e maio, momento em que óvulos maduros são obs (mais) ervados preenchendo os folículos e gonoductos. A espermatogênese foi reconhecida por uma fase proliferativa com células em desenvolvimento e apresentou seu período de maturação entre abril e julho. Estas células se diferenciaram dando origem às mórulas espermáticas e espermatozóides livres, organizando a série espermática radial. Durante o período de liberação dos gametas, a maioria dos folículos apresentou agregados de espematozóides formando esferas espermáticas as "spermballs", as quais caracterizam a espécie como espermatozeugmata. Resumo em inglês The reproductive cycle of Anodontites trapesialiswas studied from May 1998 to April 1999. Quantitative analysis of the sexual cycle revealed that the species is exclusively hermaphrodite with separate male and female follicles. Gametogenesis is continuous with peaks of maturation and elimination of gametes during dry season. The period of maximum maturation of the oogenesis was in April and May, when mature oocytes were observed filling the follicles and gonoducts. Sperma (mais) togenesis was recognized by a proliferation phase with developing cells with period of maturation since April to July. These cells started to differentiate giving origin to spermatic morulae and free spermatozoa organizing the radial spermatic series. During the period of discharge of the gamets, the majority of follicles presented aggregates of spermatozoa forming the spermballs, which characterize the species as spermatozeugmata.

Scientific Electronic Library Online (Portuguese)

2

Morfometria testicular durante o ciclo reprodutivo de Dendropsophus minutus (Peters) (Anura, Hylidae)/ Testicular morphometry during the reproductive cycle of Dendropsophus minutus (Peters) (Anura, Hylidae)

Santos, Lia R. de S.; Oliveira, Classius de
2007-03-01

Resumo em português Este estudo descreve o ciclo reprodutivo de machos de Dendropsophus minutus (Peters, 1872) com base na análise da morfometria testicular e a correlação com parâmetros climáticos. Cinqüenta indivíduos foram coletados em São José do Rio Preto, São Paulo. Após as análises macroscópicas, os testículos foram encaminhados à rotina histológica, fixados com Bouin e incluídos em historesina. Cortes de 2 µm foram corados com azul de toluidina 1% e observados ao mi (mais) croscópio. Testículos de D. minutus são órgãos pequenos (comprimento 1,90 ± 0,13 mm), esbranquiçados, com forma oval e encontrados na cavidade abdominal. Estão localizados na extremidade cranial dos rins e apresentam assimetria quanto a sua posição. Estatisticamente não há variação intra-individual no comprimento e no peso dos testículos, bem como na área e diâmetro dos lóculos seminíferos. Quanto à histologia testicular, foi possível identificar ao longo do ano nos lóculos seminíferos, todos os tipos celulares da linhagem espermatogênica, caracterizando uma gametogênese contínua, corroborada por fatores ecológicos e comportamentais. Informações sobre a morfometria testicular e ciclo reprodutivo tem importante valor biológico para anuros de regiões neotropicais. Resumo em inglês This study describes the male reproductive cycle of Dendropsophus minutus (Peters, 1872) based on testicular morphometric analysis, related to climatic conditions. Fifty individuals where collected in São José do Rio Preto, São Paulo. After macroscopic analysis, the testes were submitted to histological routine, fixed with Bouin, embedded in historesin. Sections of 2 µm were stained with 1% toluidine blue and observed to the microscope. The testes of D. minutus are sm (mais) all organs (length 1.90 ± 0.13 mm), whitish, oviform and found in the abdominal cavity. They are located in the cranial extremity of the kidneys and present asymmetry as far as position. According to statistical analyses, there is no intra-individual variation in length and weight of the testes, as well as in the area and diameter of the seminiferous locules. Concerning the testicular histology, it was possible to identify, throughout the year, in seminiferous locules, all the cellular types from the spermatogenic lineage, characterizing a continuous gametogenesis, corroborated by ecological and behavioral factors. Information about testicular morphometry and reproductive cycle has important biological value for anurans in the neotropics.

Scientific Electronic Library Online (Portuguese)

3

Eurytrema coelomaticum (Giard & Billet) (Digenea, Dicrocoeliidae) em Bradybaena similaris (Férussac) (Gastropoda, Xanthonychidae): alterações nos depósitos de cálcio e na função reprodutiva do primeiro hospedeiro intermediário/ Eurytrema coelomaticum (Giard & Billet) (Digenea, Dicrocoeliidae) em Bradybaena similaris (Férussac) (Gastropoda, Xanthonychidae): alterations in calcium deposits and in the reproductive function of its first intermediate host

Paschoal, Solange V.; Amato, Suzana B.
1996-01-01

Resumo em inglês The influence of the parasitism by the digenetic trematode Eurytrema coelomaticum (Giard & Billet, 1892) over the calcium mobilization and the reproductive function of its first intermediate host, the snail Bradybaena similaris (Férussac, 1821) was experimentally studied in infected and uninfected snails maintained in laboratory under controlled conditions of nutrition, humidity and temperature. The calcium of the shells of infected and uninfected snails was quantified b (mais) y using a technique of volumetric complexation. The amount of calcium present in the tissue was evaluated by using the histochemistry techniques of Dahl and von Kossa. The alteration in the reproductive function was evaluated through the egg production, and by histological follow up of the snails gametogenesis, in the infected and uninfected snails. The Student's test "t" showed that there was no significant difference in relation to size, weight and calcium concentration in the shells of infected and uninfected snails. The analysis of nonlinear regression, polynomial of 4th order, showed an highly positive relation to weight and size of shell to infected and uninfected snails, and an weakly significant relation to calcium concentration in the shells and shells size of infected snails. The histochemistry techniques demonstrated a large calcium deposition in the cells of the digestive glands of the infected snails when compared to the uninfected ones. The histological study of the ovotestis of the infected snails demonstrated that the gametogenesis of these snails was abnormal. The ovulogenesis was the most alterated and at 45 days post-infection the histological sections showed no ovocytes present in the ovotestis.

Scientific Electronic Library Online (Portuguese)

4

Descrição do ciclo reprodutivo de Donax hanleyanus (Bivalvia, Donacidae) no sul do Brasil/ Description of the reproductive cycle of Donax hanleyanus (Bivalvia, Donacidae) in southern Brazil

Gil, Guacira M.; Thomé, José W.
2004-09-01

Resumo em inglês The changes in gonadal development in male and female of Donax hanleyanus Philippi, 1847 are described. Gonad development and spawning seasons were assessed by monthly sampling of population from Arroio Teixeira beach, southern Brazil. Histological examination of clams showed in the most of the adult population sampled that the spawning is practically continuous, without any period of sexual rest. There are two main periods of gametogenesis, in winter and in summer, being (mais) the degree of maturation longer in the latter. The water temperature is stimulant on gametes proliferation and spawning.

Scientific Electronic Library Online (Portuguese)