924 resultados para Minnesota. Game and Fish Dept
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We have asked whether comparative genome analysis and rat transgenesis can be used to identify functional regulatory domains in the gene locus encoding the hypothalamic neuropeptides oxytocin (OT) and vasopressin. Isotocin (IT) and vasotocin (VT) are the teleost homologues of these genes. A contiguous stretch of 46 kb spanning the Fugu IT-VT locus has been sequenced, and nine putative genes were found. Unlike the OT and vasopressin genes, which are closely linked in the mammalian genome in a tail-to-tail orientation, Fugu IT and VT genes are linked head to tail and are separated by five genes. When a cosmid containing the Fugu IT-VT locus was introduced into the rat genome, we found that the Fugu IT gene was specifically expressed in rat hypothalamic oxytocinergic neurons and mimicked the response of the endogenous OT gene to an osmotic stimulus. These data show that cis-acting elements and trans-acting factors mediating the cell-specific and physiological regulation of the OT and IT genes are conserved between mammals and fish. The combination of Fugu genome analysis and transgenesis in a mammal is a powerful tool for identifying and analyzing conserved vertebrate regulatory elements.
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37-47
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19-20, 1920-1922
Changing ecology of Lake Victoria cichlids and their environment: evidence from C13 and N15 analyses
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Eutrophication is an increasing global threat to freshwater ecosystems. East Africa’s Lake Victoria has suffered from severe eutrophication in the past decades which is partly responsible for the dramatic decline in haplochromine cichlid species diversity. However, some zooplanktivorous and detritivorous haplochromine species recovered and shifted their diet towards macro invertebrates and fish. We used four formalin preserved cichlid species caught over the past 35 years to investigate whether stable isotopes of these fish are reflecting the dietary changes, habitat differences and if these isotopes can be used as indicators of eutrophication. We found that d15N signatures mainly reflected dietary shifts to larger prey in all four haplochromine species. Shifts in d13C signatures likely represented habitat differences and dietary changes. In addition, a shift to remarkably heavy d13C signatures in 2011 was found for all four species which might infer increased primary production and thus eutrophication although more research is needed to confirm this hypothesis. The observed temporal changes confirm previous findings that preserved specimens can be used to trace historical changes in fish ecology and the aquatic environment. This highlights the need for continued sampling as this information could be of essence for reconstructing and predicting the effects of environmental changes.
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Mode of access: Internet.
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Submitted to the Secretary to the Government of India, Commerce and Industry Department.
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"Including third session of the Committee on the 1950 census of the Americas."
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Kept up to date by addenda.
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Disbound Original Held in Oak Street Library Facility.
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"Publications on game birds": p. 206-215.
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Mode of access: Internet.
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Includes bibliographical references (p. 448-450).
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Mode of access: Internet.
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Includes index.
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Mode of access: Internet.