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W. T. Flueck J. M. Smith-Flueck J. Mionczynski B. J. Mincher 《European Journal of Wildlife Research》2012,58(5):761-780
Selenium (Se) is required at a fundamental physiological level in all animals. Adequate levels of Se are necessary for proper bone metabolism, iodine metabolism, immune function, reproductive success, and recruitment. Selenium is a component of enzymes which scavenge oxidative free radicals that would otherwise degrade cell membranes. Severe deficiency results in obvious symptoms such as white muscle disease in ungulates. However, more frequently, deficiency may be chronic and subclinical. Individuals then display no obvious signs of malady, yet performance suffers until their populations decline without apparent cause or through proximate factors which obscure underlying primary factors. Although well known in domestic stock, the link between population performance and Se deficiency in wild populations has been difficult to firmly establish. Confounding factors include the role of vitamin E, which also acts as an antioxidant to mitigate the need for Se under some circumstances; changing Se requirements at changing times in animal life history; changing Se requirements in relation to pollution levels and other factors causing oxidative stress; and the non-uniform distribution of Se in its various chemical forms in the environment. The latter point is especially important to wild populations that have been reduced to remnant portions of their previous range. Here, we have reviewed the literature of Se in wildlife as well as provided an introduction to Se in physiology and Se behavior in the environment for the wildlife researcher and manager. We conclude that unrecognized Se deficiency may often impede optimal population performance, and we provide recommendations for habitat analysis with regard to Se which can be used in future research. Finally, evidence that the amount of available Se in the environment is decreasing from anthropogenic causes is shown. 相似文献
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B. J. Mincher R. D. Ball T. P. Houghton J. Mionczynski P. A. Hnilicka 《European Journal of Wildlife Research》2008,54(2):193-198
Geophagia has been commonly reported for bighorn sheep (Ovis canadensis) and other ungulates worldwide. The phenomenon is often attributed to the need to supplement animal diets with minerals available
in the soil at mineral lick locations. Sodium is the mineral most frequently cited as being the specific component sought,
although this has not been found universally. In this study area, bighorn sheep left normal summer-range to make bimonthly
26-km, 2,000-m-elevation round-trip migrations, the apparent purpose of which was to visit mineral licks on normal winter-range.
Lick soil and normal summer-range soil were sampled for their available mineral content and summer-range forage was sampled
for total mineral content, and comparisons were made to determine the specific components sought at the lick by bighorn sheep
consuming soil. It was concluded that bighorn sheep were attracted to the lick by a desire for sodium but that geophagia also
supplemented a diet deficient in the trace element selenium. Where sheep are denied access to licks, populations may be limited
by mineral deficiency. 相似文献
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Schofield DJ Pope AR Clementel V Buckell J Chapple SDj Clarke KF Conquer JS Crofts AM Crowther SR Dyson MR Flack G Griffin GJ Hooks Y Howat WJ Kolb-Kokocinski A Kunze S Martin CD Maslen GL Mitchell JN O'Sullivan M Perera RL Roake W Shadbolt SP Vincent KJ Warford A Wilson WE Xie J Young JL McCafferty J 《Genome biology》2007,8(11):R254-18
We have created a high quality phage display library containing over 1010 human antibodies and describe its use in the generation of antibodies on an unprecedented scale. We have selected, screened and sequenced over 38,000 recombinant antibodies to 292 antigens, yielding over 7,200 unique clones. 4,400 antibodies were characterized by specificity testing and detailed sequence analysis and the data/clones are available online. Sensitive detection was demonstrated in a bead based flow cytometry assay. Furthermore, positive staining by immunohistochemistry on tissue microarrays was found for 37% (143/381) of antibodies. Thus, we have demonstrated the potential of and illuminated the issues associated with genome-wide monoclonal antibody generation. 相似文献
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Background
In a number of species males damage females during copulation, but the reasons for this remain unclear. It may be that males are trying to manipulate female mating behaviour or their life histories. Alternatively, damage may be a side-effect of male-male competition. In the black scavenger or dung fly Sepsis cynipsea (Diptera: Sepsidae) mating reduces female survival, apparently because males wound females during copulation. However, this damage does not seem to relate to attempted manipulation of female reproduction by males. Here we tested the hypothesis that harming females during mating is an incidental by-product of characters favoured during pre-copulatory male-male competition. We assessed whether males and their sons vary genetically in their ability to obtain matings and harm females, and whether more successful males were also more damaging. We did this by ranking males' mating success in paired competitions across several females whose longevity under starvation was subsequently measured. 相似文献30.