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排序方式: 共有146条查询结果,搜索用时 31 毫秒
101.
Morphological analysis of Brandt's hedgehog (Paraechinus hypomelas) reflects the isolation history of Persian Gulf islands and has implications for taxonomy
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![点击此处可从《Biological journal of the Linnean Society. Linnean Society of London》网站下载免费的PDF全文](/ch/ext_images/free.gif)
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A major challenge in understanding energy balance is deciphering the neural and molecular circuits that govern behavioral, physiological, and metabolic responses of animals to fluctuating environmental conditions. The neurally expressed TGF-β ligand DAF-7 functions as a gauge of environmental conditions to modulate energy balance in C. elegans. We show that daf-7 signaling regulates fat metabolism and feeding behavior through a compact neural circuit that allows for integration of multiple inputs and the flexibility for differential regulation of outputs. In daf-7 mutants, perception of depleting food resources causes fat accumulation despite reduced feeding rate. This fat accumulation is mediated, in part, through neural metabotropic glutamate signaling and upregulation of peripheral endogenous biosynthetic pathways that direct energetic resources into fat reservoirs. Thus, neural perception of adverse environmental conditions can promote fat accumulation without a concomitant increase in feeding rate. 相似文献
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S. M. Hosseini M. Fazilati F. Moulavi M. Foruzanfar M. Hajian P. Abedi N. Nasiri A. K. Kaveh A. H. Shahverdi M. R. Hemami M. H. Nasr-Esfahani 《European Journal of Wildlife Research》2009,55(3):239-246
Although the potential use of reproductive biotechnology for safeguarding of endangered wildlife species is undoubted, initial
evaluation of the genetic and reproductive relationship between the endangered mammals and those closely related species is
indispensable. Isfahan mouflon Ovis orientalis isphahanica is now considered as a threatened species by International Union for the Conservation of Nature. Therefore, little is known
about the biology of this species. This study was carried out to investigate the possible reproductive potential of domestic
sheep for ex situ conservation of the Isfahan mouflon. Somatic cell cultures were taken from ear biopsies of the wild and
domestic sheep and were used for karyotype analysis. Semen samples were collected by electroejaculator from the wild and domestic
rams. The spermatological characteristics of the collected semen samples were determined and used for both cryopreservation
and cross-insemination of the synchronized wild and domestic female sheep. To establish a cryobank for the threatened species
biomaterials, freezed samples of the somatic cells and semen were transferred to a cryotank. The result suggested that Isfahan
mouflon has conserved its chromosomal integrity as previously observed and contains the same chromosomal number as the domestic
sheep (2n = 54). The semen samples of both species revealed similar cryoviability (>35% gross motility postthawing). Cross-insemination
of both species resulted in successful pregnancy. It was suggested that domestic sheep possesses the required biological characteristics
to be considered for safeguarding of the Isfahan mouflon. 相似文献
106.
O'Brien TJ Jiang G Chun G Mandel HG Westphal CS Kahen K Montaser A States JC Patierno SR 《Mutation research》2006,610(1-2):85-92
Some hexavalent chromium [Cr(VI)]-containing compounds are lung carcinogens. Once within cells, Cr(VI) is reduced to trivalent chromium [Cr(III)] which displays an affinity for both DNA bases and the phosphate backbone. A diverse array of genetic lesions is produced by Cr including Cr-DNA monoadducts, DNA interstrand crosslinks (ICLs), DNA-Cr-protein crosslinks (DPCs), abasic sites, DNA strand breaks and oxidized bases. Despite the large amount of information available on the genotoxicity of Cr, little is known regarding the molecular mechanisms involved in the removal of these lesions from damaged DNA. Recent work indicates that nucleotide excision repair (NER) is involved in the processing of Cr-DNA adducts in human and rodent cells. In order to better understand this process at the molecular level and begin to identify the Cr-DNA adducts processed by NER, the incision of CrCl(3) [Cr(III)]-damaged plasmid DNA was studied using a thermal-resistant UvrABC NER endonuclease from Bacillus caldotenax (Bca). Treatment of plasmid DNA with Cr(III) (as CrCl(3)) increased DNA binding as a function of dose. For example, at a Cr(III) concentration of 1 microM we observed approximately 2 Cr(III)-DNA adducts per plasmid. At this same concentration of Cr(III) we found that approximately 17% of the plasmid DNA contained ICLs ( approximately 0.2 ICLs/plasmid). When plasmid DNA treated with Cr(III) (1 microM) was incubated with Bca UvrABC we observed approximately 0.8 incisions/plasmid. The formation of endonuclease IV-sensitive abasic lesions or Fpg-sensitive oxidized DNA bases was not detected suggesting that the incision of Cr(III)-damaged plasmid DNA by UvrABC was not related to the generation of oxidized DNA damage. Taken together, our data suggest that a sub-fraction of Cr(III)-DNA adducts is recognized and processed by the prokaryotic NER machinery and that ICLs are not necessarily the sole lesions generated by Cr(III) that are substrates for NER. 相似文献
107.
Topical non-iontophoretic application of acetylcholine and nitroglycerin via a translucent patch: a new means for assessing microvascular reactivity
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Schonberger RB Worden WS Shahmohammadi K Menn K Silverman TJ Stout RG Shelley KH Silverman DG 《The Yale journal of biology and medicine》2006,79(1):1-7
Objective: Assessments of endothelial cell function with acetylcholine have typically used systemic, regional intra-arterial, or iontophoretic delivery of drug. Each of these techniques induces systemic and/or local changes that compromise their safety or effectiveness. Using translucent drug preparations applied under laser Doppler flowmetry (LDF) probes, we tested whether local vasodilation can be induced with non-iontophoretic transdermal delivery of acetylcholine and how such dilation would compare to the dilation achieved with topical nitroglycerin in healthy volunteers. Methods: Ten subjects without known vascular disease were recruited for LDF monitoring at sites of drug application for this preliminary investigation. Topical acetylcholine chloride, nitroglycerin, and placebo were applied via translucent patches to the forehead directly below LDF probes. Results: LDF readings increased by 406 percent (245 percent to 566 percent) and 36 percent (26 percent to 46 percent), respectively, at the acetylcholine and placebo sites (p = .005 by Wilcoxon Signed Rank Test (WSRT) for acetylcholine vs. placebo); and they increased by 365 percent (179 percent to 550 percent) at the nitroglycerin site (p = .005 by WSRT for nitroglycerin vs. placebo; p = .6 vs. acetylcholine). Conclusion: Transdermal delivery of acetylcholine can induce significant local vasodilatory responses comparable to those achieved with nitroglycerin without requiring iontophoresis. The means of transdermal delivery and monitoring described herein may constitute a new minimally invasive way to interrogate the microvasculature and thereby assess the microcirculatory changes induced by various disorders and therapeutic interventions. 相似文献
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Moghadam Maryam Tokhanbigli Samaneh Baghaei Kaveh Farivar Shirin Asadzadeh Aghdaei Hamid Zali Mohammad Reza 《Molecular biology reports》2020,47(3):1723-1732
Molecular Biology Reports - Mesenchymal Stem Cells (MSCs) have therapeutic potential in a variety of diseases; however, the safety and efficacy of their use remain ambiguous. Clinical applications... 相似文献
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