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  • 1
    Electronic Resource
    Electronic Resource
    Oxford, UK; Malden, USA : Blackwell Science Ltd
    Journal of fish biology 65 (2004), S. 0 
    ISSN: 1095-8649
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Reproductive traits of fish such as age at first maturation or fecundity are not fixed: there is growing evidence that they change through time under the influence of various environmental factors, including fishing. Because these parameters are important in determining population dynamics, a better understanding of these changes is important to fisheries stock assessment. However, field studies are often inconclusive with respect to the ultimate causes of a given change. Although numerous experimental studies have been assessed the influence of environmental factors such as temperature on the reproduction in fish, these generally focus on single factors and do not consider the effects of the origin and individual history of experimental fish. There is scope for the development of ecological experiments to investigate the effects of interacting environmental factors on reproduction at the individual and population levels. This presentation will review experiments that could be used to predict environmental influences in the wild and the limits to such extrapolations. Finally, we will present a set of experiments designed to study maturation reaction norms in fish, i.e. the size at first reproduction as a function of age. We will investigate the effects of genotypes and environmental effects (feeding and temperature) on growth, age at maturity and subsequent spawning performances in reared cohorts.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1365-2559
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: A bronchial P cell carcinoid, which was negative for all hormones immunocytochemically tested, showed a globular intracytoplasmic inclusion in almost every cell. The inclusions were not clearly distinguishable using the haematoxylin-eosinsafran procedure; they were best demonstrated with the Masson trichrome stain and the Grimelius technique and were easily detected in 1 μm thick Epon sections as target-like structures. On electron microscopy, they were found to be composed of filamentous aggregates entrapping a few endosecretory granules, which showed degenerative changes. The filaments, 8–10 nm in diameter, lacked any periodicity; they were randomly dispersed in the central area and arranged in broken concentric swirls at the periphery of the inclusions. The globules lacked the tinctorial properties of amyloid, but showed a strong immunostaining for keratin-like proteins. A systematic investigation of 12 APUDomas of bronchial or duodenopancreatic origin, using both light and electron microscopy, identified a few filamentous bodies in one case, a somatostatin cell tumour of ampulla of Vater. In both cases, the structures appeared similar to those previously reported in growth hormone cell pituitary adenomas as well as in a few bronchial or gut carcinoids. Whatever their nature, morphological data suggest that they are related to abnormalities in the secretory function, involving the Golgi apparatus, the endosecretory granules and the microtubular microfilamentous system.
    Type of Medium: Electronic Resource
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