The balanced segregation of homologous chromosomes during meiosis is essential for fertility and is mediated by crossovers (COs). A strong reduction of CO number leads to the unpairing of homologous chromosomes after the withdrawal of the synaptonemal complex. This results in the random segregation of univalents during meiosis I and ultimately to the production of unbalanced and sterile gametes.
View Article and Find Full Text PDFRats subjected to various accelerations (+G) exhibited increased levels of plasma epinephrine (EPI), norepinephrine (NE), and corticosterone. However, the collection of blood was performed after a centrifugation finished, and therefore the levels could be affected by the process of deceleration. The aim of this study was to evaluate plasma EPI, NE, and corticosterone levels in blood collected directly during centrifugation after reaching different G (2-6), using newly developed remote-controlled equipment.
View Article and Find Full Text PDF1. Birds have been proposed as a suitable model for studies on ageing because of their long life in comparison with similar-sized mammals. However, some weak fliers, such as Galliformes, are the exception to this rule.
View Article and Find Full Text PDFComp Biochem Physiol A Mol Integr Physiol
November 2006
The effect of feed restriction on plasma hormones (triiodothyronine - T(3), thyroxine - T(4), and corticosterone), protein, lipid, carbohydrate, and mineral metabolism and activity of plasma enzymes (creatine kinase, alkaline phosphatase, aspartate aminotransferase, and alanine aminotransferase) were studied in meat type female chickens (Gallus gallus). Ad libitum fed birds were compared with those subjected to severe and moderate quantitative feed restriction from 16 to 100 days of age. Feed restriction elevated plasma T(4) and corticosterone levels and reduced T(3).
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