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| Registros recuperados: 11 | |
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| Suckling, Coleen C.; Clark, Melody S.; Richard, Joelle; Morley, Simon A.; Thorne, Michael A. S.; Harper, Elizabeth M.; Peck, Lloyd S.. |
| This study examined the effects of long-term culture under altered conditions on the Antarctic sea urchin, Sterechinus neumayeri.Sterechinus neumayeri was cultured under the combined environmental stressors of lowered pH (-03 and -05 pH units) and increased temperature (+2 degrees C) for 2years. This time-scale covered two full reproductive cycles in this species and analyses included studies on both adult metabolism and larval development. Adults took at least 6-8months to acclimate to the altered conditions, but beyond this, there was no detectable effect of temperature or pH. Animals were spawned after 6 and 17months exposure to altered conditions, with markedly different outcomes. At 6months, the percentage hatching and larval survival rates were... |
| Tipo: Text |
Palavras-chave: CO2; Echinoderm; Gonad maturation; Larval development; Oxygen consumption; Vitellogenesis. |
| Ano: 2015 |
URL: https://archimer.ifremer.fr/doc/00617/72874/71930.pdf |
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| Guzmán Riffo, C.N.. |
| Debido a la importancia que han adquirido los especímenes neomachos en la producción de poblaciones todo-hembras triploides, se ha hecho cada vez mas necesario investigar la manera de poder reconocer su condición sexual sin la necesidad de sacrificar al pez. Este conocimiento permitiría entregar al acuicultor una herramienta necesaria para el manejo de éstos stoks. En este estudio se analiza la factibilidad de reconocer a un neomacho de trucha arcoiris (Oncorhynchus mykiss), por medio de un análisis serológico, basándose en que un neomacho por ser un individuo hembra revertido hormonalmente de sexo, presentaría niveles detectables de la proteína femenina vitelogenina. Se compararon las concentraciones de proteínas séricas presentes en machos, hembras,... |
| Tipo: Theses and Dissertations |
Palavras-chave: Vitellogenesis; Serological studies; Immunoassays. |
| Ano: 2003 |
URL: http://hdl.handle.net/1834/4556 |
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| Srivastav,S.K.; Srivastav,A.K.. |
| Adult Channa punctatus murrels of both sexes (60-80 g) were collected locally from Ramgarh Lake during the second week of every month (10 individuals of each sex/month) throughout the year. Blood samples were collected and analyzed for serum calcium and phosphate levels by the methods of Trinder (1960) and Fiske and Subbarow (1925), respectively. Gonads were fixed to judge the state of maturation of the fish. Males exhibited no change in serum calcium levels throughout the year in correlation with testicular maturation. However, serum phosphate levels exhibited a rise in correlation with the increased gonadosomatic index. Females showed marked seasonal changes in serum calcium and phosphate levels which were associated with ovarian maturation... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Calcium; Inorganic phosphate; Reproduction; Teleost; Vitellogenesis. |
| Ano: 1998 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X1998000800006 |
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| Oliveira,Classius de; Santos,Lia Raquel de Souza. |
| This paper describes morphological characteristics of the ovarian germinative cells of the Scinax fuscovarius (Lutz, 1925). The ovary is organized in primordial germinative cells (oogonia) and follicular structures (ovarian follicle) - oocytes surrounded by follicular cells. Oogonia: their nests are peripherically localized, containing cells with large and oval nucleus. Oocytes I: basophilic cytoplasm; the spherical nucleus presents few nucleoli, one or two; the follicular cells (one tenuous layer) surround these previtellogenic cells. Oocytes II: the cell is larger and the cytoplasm becomes more basophilic; the nucleus presents few nucleoli and contains many chromosomes in the periphery (beginning the perinucleolar stage). Oocytes III: the cytoplasm... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Oocytes; Oogonia; Ovary; Pigment; Vitellogenesis. |
| Ano: 2004 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0101-81752004000400029 |
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| Vélez-Arellano,Nurenskaya; Shibayama,Mineko; Ortíz-Ordoñez,Esperanza; Silva-Olivares,Angélica; Arellano-Martínez,Marcial; García-Domínguez,Federico. |
| This paper describes the oogenesis of Chiton virgulatus, based on histological observations under transmission and scanning electron microscopy. Three oocyte types were identified: i) previtellogenic oocytes with a mean diameter of 50±20.5 µm, surrounded by elongated follicular cells of approximately 5 µm, ii) immature vitellogenic oocytes with a mean diameter of 113±15.3 µm and small cytoplasmic projections denoting the onset of the oocyte hull development; adjacent to each projection are pores approximately 0.7 µm in diameter, and iii) mature vitellogenic oocytes with a mean diameter of 146±24.8 µm; the oocyte cytoplasmic projections grow and its apical zone becomes trident-shaped; follicular cells adopt a bulbous shape due to the growth of the... |
| Tipo: Journal article |
Palavras-chave: Egg hull; Vitellogenesis; Ultrastructure. |
| Ano: 2014 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-95022014000200038 |
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| Buchet, Vincent; Coquard, Elodie; Severe, Armelle; Barone, Herve. |
| Sea bass, Dicentrarchus labrax (mean weight: 748 +/- 13 g), were maintained before and during vitellogenesis in 1, 3, 8, 16 and 32 m(3) tanks, and then they were transferred to 2 m(3) tanks, for the spawning season. During the first 2 months of the experiment, the growth rates were significantly lower in smaller tanks (1 m(3)). In August, the oocyte diameters were significantly lower in smaller tanks (1, 3 and 8 m(3)) than in larger (16-32 m(3)) tanks. At the end of the experiment, the fish mean weight in the 1 m(3) tanks was significantly lower than in the 3 m(3) tanks, but oocyte diameters and plasma oestradiol concentrations were not significantly different between the volumes. This shows a longer acclimation requirement in smaller volume rearing.... |
| Tipo: Text |
Palavras-chave: Volume; Aquaculture; Vitellogenesis; Reproduction; Sea bass. |
| Ano: 2008 |
URL: http://archimer.ifremer.fr/doc/2008/publication-4068.pdf |
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| Benmeradi, N. |
| During the reproductive period, the microscopical observation of Patella coerulea ovary shows some ovogonies forming neets, supported by a conjonctive network, previtellogenic oocytes which leave gradually the conjonctive tissue and vitellogenic oocytes isolated in the acinus lumen. In early stages of previtellogenesis, an important nucleolar activity, caracterised by cloud-shaped or nematosomes and ribonucleoproteinic extrusions in cytoplasm compartment can be observed. At the end of this stage, the oocyte becomes richer in organites, mitochondria, granular endoplasmic reticulum and Golgi. We further notice the outcome of the first vitellin platelets. Production of vitellus is higher as three kinds of vitellus are observed in the following order: dark... |
| Tipo: Text |
Palavras-chave: Ultrastructure; Oogenesis; Sexual reproduction; Vitellogenesis. |
| Ano: 1991 |
URL: http://archimer.ifremer.fr/doc/1991/acte-1720.pdf |
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| Branco,Ilka S. L.; Viana,Danielle L.; Félix,Renata T. S.; Véras,Dráusio P.; Hazin,Fábio H. V.. |
| The oogenesis is a key stage in the reproductive development of an organism, which can be best understood from histological analysis of ovaries in different maturity stages. In order to provide information on the reproductive biology of the black triggerfish, M. niger, in particular on its oogenesis process, this study aimed at identifying and characterizing the oocyte development stages and its organization within the different stages of ovarian maturation based on specimens from São Pedro e São Paulo Archipelago. In this present report, a number of 294 ovaries were histologically analyzed. It was verified that they are composed of ovigerous lamellae containing oocytes at different development stages. Five different stages of oogenesis were identified:... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Histology; Oogenesis; Reef fish; Reproduction; Vitellogenesis. |
| Ano: 2013 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1679-62252013000300597 |
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| Atella,Georgia C.; Gondim,Katia C.; Machado,Ednildo A.; Medeiros,Marcelo N.; Silva-Neto,Mário A.C.; Masuda,Hatisaburo. |
| In triatomines, as well as in other insects, accumulation of yolk is a process in which an extra-ovarian tissue, the fat body, produces yolk proteins that are packed in the egg. The main protein, synthesized by the fat body, which is accumulated inside the oocyte, is vitellogenin. This process is also known as vitellogenesis. There are growing evidences in triatomines that besides fat body the ovary also produces yolk proteins. The way these yolk proteins enter the oocyte will be discussed. Yolk is a complex material composed of proteins, lipids, carbohydrates and other minor components which are packed inside the oocyte in an organized manner. Fertilization triggers embryogenesis, a process where an embryo will develop. During embryogenesis the yolk will... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Oogenesis; Vitellogenesis; Embryogenesis; Triatomines; Rhodnius prolixus. |
| Ano: 2005 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0001-37652005000300005 |
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| Santos,Hellen S.; Santos,Jamile M.S.; Matos,Maria H.T.; Silva,Naisandra B.; Freire,Eliza M.X.; Ribeiro,Leonardo B.. |
| The reproductive cycle of Squamata reptiles is often associated with environmental conditions, such as rainfall. In this respect, seasonal variations may affect the morphology of the ovarian follicles, which are associated with vitellogenesis. The present study describes histological alterations in the ovarian cycle of two lizard species, Tropidurus hispidus (Spix, 1825) and Tropidurus semitaeniatus (Spix, 1825), which inhabit a caatinga region in the state of Rio Grande do Norte. Our goal was to identify morphological differences in the ovarian follicles at each phase of vitelloge nesis and to ascertain if they are associated with rainfall. Three follicular phases were identified in both species: pre-vitellogenesis, vitellogenesis and follicular atresia.... |
| Tipo: Info:eu-repo/semantics/other |
Palavras-chave: Ovarian stages; Reproductive cycle; Semiarid; Vitellogenesis. |
| Ano: 2015 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1984-46702015000100086 |
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| Fortes,P; Salvador,G; Cônsoli,FL. |
| Ovary development and maturation of Nezara viridula (L.) were evaluated by examining ovariole morphology and the alterations in the biochemical (protein synthesis related to reproduction) composition of the hemolymph. Quantitative and qualitative protein analyses were performed and ovary structural alterations for the pre-reproductive and reproductive stages were recorded. Total concentration of proteins in female hemolymph gradually increased until the end of the pre-mating stage, remaining unaltered thereafter. Proteins linked to reproduction (vitellogenins) appeared in the hemolymph 10 days after adult emergence and indicated the end of the pre-mating stage. After mating, total protein concentration in the hemolymph was lower compared to virgin females;... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Vitellogenesis; Reproduction; Oocyte. |
| Ano: 2011 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1519-566X2011000100013 |
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| Registros recuperados: 11 | |
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