991 resultados para 796:396


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本发明涉及一种强抗氧化活性的组合物,包括仿刺参多肽和香菇多糖,它们间的质量比是1:1-100。采用南京建成生物工程研究所试剂盒(T-AOC)测定酶解液总抗氧化活性。结果发现:木瓜蛋白酶水解后的仿刺参酶解液抗氧化活性明显增强,由最初的10.08单位/mg蛋白增至27.59单位/mg蛋白;将无抗氧化活性的香菇多糖浸提液按照不同比例和仿刺参酶解液混合后,组合物的抗氧化活性可进一步提升。当仿刺参酶解液与香菇多糖浸提液体积比为1:4时,抗氧化活性达到最高值84.09单位/mg蛋白,相应对照组的抗氧化活性则为47.54单位/mg蛋白。研究结果表明木瓜蛋白酶水解可以增强仿刺参的抗氧化活性,而香菇多糖浸提液又可进一步增强仿刺参酶解产物的抗氧化活性。本发明可用于具有增强机体抗氧化活性、延缓衰老的功能性食品的开发。

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Studies on reproductive biology and artificial propagation including larval rearing of freshwater mud eel, Monopterus cuchia and spiny eel, Mastacembelus armatus were attempted. The gonadosomatic index (GSI) of mud eel ranged from 0.41 (August) to 5.52 (June) in males and 0.53 (August) to 7.61 (June) in females. In both cases the GSI showed a peak in June. Fecundity ranged from 228 (TL - 396 mm; W - 78g) to 5510 (TL - 865 mm; W - 630 g). In case of spiny eel, the GSI varied from 0.65 (August) to 8.30 (July) in males and 0.70 (August) to 10.46 (July) in females. GSI showed single peak in July. Fecundity ranged from 570 (TL - 240 mm; W - 30 g) to 10870 (TL - 601; W - 350g). Histology of the testes and ovaries of the eels were carried out to investigate the gonadal development stages during the reproductive months (August to November 2003). In case of male M. cuchia, the secondary primordial germ cells, primary spermatogonium, some spermatogonia A and clone of spermatogonium B in testis were observed in September. In October-males different sized lobules having spermatogonia, spermatocytes and spermatids were observed. In the ovary of M. cuchia, polygonal shaped oocytes were seen during September. The oogonia were reduced with dense and irregular shaped during October. Numerous pycnotic cells were visible during November. In male M. armatus numerous broken lobule walls were found in testes during September. In October, abundant primary germ cells, pycnotic nests of degenerating cells, spermatogonia and spermatids were observed. In females, ovaries had distinct yolk vesicles stage and yolk granules stages in August. In September, the follicular cells of the oogonia were ruptured, shrunk forming irregular shaped in October. Oogonia were also shrunk with thin, irregular shaped structure but broken parts of the ruptured follicular cells were scattered in case of M. armatus. Experimental attempts on artificial propagation indicated that both freshwater eels were difficult to breed using inducing agents like pituitary glands (PG) of 10, 20, 50, 100 and 150 mg per kg of body weight. Same doses were used for both sexes with equal sex-ratio. In both cases, brood fish died at higher doses of injection given at 100 and 150 mg PG/kg bodyweight. However, M. cuchia breed naturally in cisterns when provided with water hyacinths and tunnel in muddy bottom. M. cuchia fed with chopped cooked fish attained a mean weight of 18.75 ± 2.3 g and cent percent survival. While in case of M. armatus best growth by weight (12.0 ± 2.48 g) and cent percent survival were achieved using chopped raw fish. Car tyre was observed as best shelter for attaining the mean weight gain 22.53 ± 2.24 g and cent percent survival of M. cuchia. While PVC pipe was found to be the best shelter for M. armatus, where it attained the mean weight of 12.73 ± 1.88 g and cent percent survival.

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首次报道金环蛇蛇毒PLA_(2)的基因,根据序列比较分析,这2个磷脂酶A_(2)基因所编码的蛋白质序列结构均区别于已报道的金环蛇蛇毒磷脂酶A_(2),是2个新的金环蛇蛇毒磷脂酶A_(2),分别命名为金环蛇蛇毒磷脂酶A_(2) Ⅰ(Bf-PLA_(2) Ⅰ)和金环蛇磷脂酶A_(2) Ⅱ(Bf-PLA_(2) Ⅱ)。

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Amphibian skin is a rich resource of antimicrobial peptides like maximins and maximins H from toad Bombina maxima. A novel cDNA clone encoding a precursor protein that comprises maximin 3 and a novel peptide. named maximin H5. was isolated from a skin cDNA library of B. maxima. The predicted primary structure of maximin H5 is ILGPVLGLVSDTLDDVLGIL-NH2,. Containing three aspartate residues and no basic amino acid residues. maximin H5 is characterized by an anionic property. Different from cationic maximin H peptides. only Gram-positive strain Staphylococcus aureus was sensitive to maximin H5. while the other bacteria] and fungal strains tested ere resistant to it. The presence of metal ions. like Zn2+ and Mg2+, did not increase its antimicrobial potency. Maximin H5 represents the first example of potential anionic antimicrobial peptides from amphibians, The results provide the first evidence that. together kith cationic antimicrobial peptides. anionic antimicrobial peptides may also exist naturally as part of the innate defense system. (C), 2002 Elsevier Science (USA). All rights reserved.

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二花脸猪、杜洛克猪群内遗传距离指数分别为0.0371、0.0345,遗传多样性指数分别为0.486、0.431,两品种间存在着DNA分子水平上的差异;利用RAPD技术可以快速有效地检测猪的DNA多态性,RAPD技术在猪基因组研究中有广阔的应用前景。

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蛋白质内含子是能够自我剪切的一段多肽链。它在生物三大系统中都存在,但它的分布在各物种间以及蛋白质种类之间极不均衡。蛋白质内含子的演化和扩散也因此引起了人们的极大兴趣。经过系统搜索,从已知的核酸序列中找到69个经典的蛋白质内含子。同源比较和系统树分析表明,蛋白质内含子的演化应综合先天遗传和后天转移两方面的因素。

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Inteins are internal segment peptides which can self-splicing at the protein level. Although inteins are found in all three domains of life, they are not evenly distributed among species and proteins. So the evolution of intein have been capturing much at

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An improved understanding of lean fuel turbulent premixed flames must play a central role in the fundamental science of these new concepts.

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在戊巴比妥钠麻醉的Sprague-Dawley大鼠上,运用海马Schaffer-CA1双通路条件化作用(低频配对,600对脉冲,5Hz,配对刺激相应的兴奋性突触后电位峰值时间间隔为10ms)在两条Schaffer-CA1条件化通路上同时诱导出突触可塑性,呈现出海马组合突触可塑性.结果显示:不管海马Schaffer-CA1双通路独立与否,双通路条件化作用均可以同时诱导出长时程增强(long-term potentiation,LTP)和长时程抑制(long-term depression,LTD),呈现出LTP/LTD组合突触可塑性.结果表明:海马Schaffer-CA1双通路技术,可实现海马突触可塑性的双向诱导,可塑性的方向取决于突触的自身状态.由此提示,与传统的高频诱导LTP低频诱导LTD相比,在海马Schaffer-CA1双通路条件化作用诱导出的组合突触可塑性可以吏好地编码海马相关的学习记忆,体现了海马突触可塑性的灵活性与稳定性.

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2005年3~4月,对云南省临沧地区澜沧江自然保护区的鸟类资源进行了调查.通过观察和网捕调查,共计采集记录105种鸟类.结合中国科学院昆明动物研究所鸟类标本室收藏的临沧地区的207种鸟类标本,以及该地区的有关文献资料记录的84种,保护区内共有396种鸟类,隶属55 科(另4亚科)19 目,占云南省所录鸟类种数848种的47%,全国鸟类种数1331种的30%.其中国家一级保护物种2种,二级保护物种39种.保护区内记录的鸟类有留鸟307种,占所录鸟类的78%.区系成分以东洋界物种为主,有292种,占繁殖鸟类总种数的83%.亚区级区系分析表明保护区内的鸟类以滇南山地亚区和西南山地亚区的种类为主,前者成分稍多于后者,说明该地区处于由滇南山地亚区向西南山地亚区过渡的地带.结合该区鸟类垂直分布的特点,提出应加强对原生及次生阔叶林的保护,尤其是对成熟次生林的保护,因为它们对保存该保护区的大多数物种具有重要的价值.

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Ras superfamily proteins are key regulators in a wide variety of cellular processes. Previously, they were considered to be specific to eukaryotes, and MglA, a group of obviously different prokaryotic proteins, were recognized as their only prokaryotic an

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Using a combined computational program. we identified 50 potential microRNAs (miRNAs) in Giardia lamblia. one of the most primitive unicellular eukaryotes. These miRNAs are unique to G. lamblia and no homologues have been found in other organisms; miRNAs.