Results 171 to 180 of about 13,138 (208)
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1985
Fertilized eggs are the crossroads of development. They represent both the origin and the biological goal of each individual organism. Eggs provide in two ways for the embryo they enclose: They contain developmental instructions given by the mother to direct the initial phases of embryogenesis (see Chapters 11–13), and they are usually provisioned with
POSTLETHWAIT JH, GIORGI, FRANCO
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Fertilized eggs are the crossroads of development. They represent both the origin and the biological goal of each individual organism. Eggs provide in two ways for the embryo they enclose: They contain developmental instructions given by the mother to direct the initial phases of embryogenesis (see Chapters 11–13), and they are usually provisioned with
POSTLETHWAIT JH, GIORGI, FRANCO
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Vitellogenesis in two spathebothriidean cestodes
Parasitology Research, 2005Vitellogenesis in two spathebothriidean tapeworms, dixenous adult Cyathocephalus truncatus and monoxenous progenetic Diplocotyle olrikii, has been examined using transmission electron microscopy and cytochemical staining with periodic acid-thiosemicarbazide-silver proteinate for glycogen.
M. Brunanska +2 more
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1987
In vertebrates, there are three principal modes of nutrition for developing embryos: (1) the laying down of food stores, synthesized in the liver, in the oocyte (vitellogenesis) (this is the most common mode in nonmammalian species); (2) the direct provision of nutrients to the developing young through the intermediary of the uterine wall by either ...
Ian P. Callard, S.-m. Ho
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In vertebrates, there are three principal modes of nutrition for developing embryos: (1) the laying down of food stores, synthesized in the liver, in the oocyte (vitellogenesis) (this is the most common mode in nonmammalian species); (2) the direct provision of nutrients to the developing young through the intermediary of the uterine wall by either ...
Ian P. Callard, S.-m. Ho
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Vitellogenesis and the Vitellogenin Gene Family
Science, 1981Vitellogenin is synthesized under estrogen control in the liver, extensively modified, transported to the ovary, and there processed to the yolk proteins lipovitellin and phosvitin. In the frog Xenopus laevis there are at least four distinct but related vitellogenin genes.
W, Wahli +3 more
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2003
In the Japanese eel Anguilla japonica, oocyte development has not been observed to occur under ordinary rearing conditions. Therefore, hormonal treatment is necessary to induce ovarian maturation artificially. Weekly injections of aqueous extract of salmon pituitaries were generally conducted for inducing vitellogenesis (Yamauchi and Yamamoto 1982). 17,
Narumi Sato +3 more
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In the Japanese eel Anguilla japonica, oocyte development has not been observed to occur under ordinary rearing conditions. Therefore, hormonal treatment is necessary to induce ovarian maturation artificially. Weekly injections of aqueous extract of salmon pituitaries were generally conducted for inducing vitellogenesis (Yamauchi and Yamamoto 1982). 17,
Narumi Sato +3 more
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Regulation of locust vitellogenesis
Trends in Biochemical Sciences, 1983The reproduction of insects is frequently synchronized to the availability of specific host plants or to seasonal climatic condi- tions. Synchronization is achieved in most cases either by migration to favourable habitats or by diapause, a genetically determined state of suppressed develop- mental and metabolic rates, frequently induced by photoperiod,
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Cirriped vitellogenesis: Effect of ecdysterone in vitro
General and Comparative Endocrinology, 1977Abstract Ovarioles of Balanus amphitrite and B. eburneus were cultured with ecdysterone in medium (10−4–1 μg/ml). Yolk droplets of mature oocytes showed increasing degeneration with increasing concentration of ecdysterone. Other ovarian cells, cement gland cells, and mantle parenchyma were not affected to any extent. Although preliminary, the results
U E, Fyhn, H J, Fyhn, J D, Costlow
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Active vitellogenesis in precocene-treated Locusta migratoria
General and Comparative Endocrinology, 1981Abstract Vitellogenesis continues unhindered during the first 2 days after precocene II treatment of vitellogenic female locusts bearing terminal oocytes up to 4 mm in length. The growth rate of these oocytes remains normal, but the corpora allata of treated females are inactive insofar as juvenile hormone synthesis is concerned.
E, Lubzens, P, Moshitzky, S W, Applebaum
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Multihormonal Control of Vitellogenesis in Lower Vertebrates
2004The comparative approach on how and when vitellogenesis occurs in the diverse reproductive strategies displayed by aquatic and terrestrial lower vertebrates is presented in this chapter; moreover, attention has been paid to the multihormonal control of hepatic vitellogenin synthesis as it is related to seasonal changes and to vitellogenin use by ...
POLZONETTI, Alberta Maria +4 more
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