共查询到20条相似文献,搜索用时 15 毫秒
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复合微生态制剂对雏鸡实验性感染鸡白痢沙门菌病的预防实验 总被引:1,自引:0,他引:1
实验用200羽伊莎B-380雏鸡,随机分为5组,在1~3组雏鸡日粮中分别添加0.5%、1.0%、1.5%HM-强效复合微生态制剂,第4组日粮中添加0.2%氟哌酸,第5组饲料中不添加任何药物作为空白对照,用鸡白痢沙门菌进行人工感染,以观其药物的保护作用。结果显示添加0.5%HM-强效复合微生态制剂有98%的保护率,添加1.0%、1.5%HM-强效复合微生态制剂和添加0.2%氟哌酸有100%的保护率,检查发现添加HM-强效复合微生态制剂组雏鸡肠道中大肠埃希菌明显减少,而乳酸杆菌和双歧杆菌有益微生物明显增多。 相似文献
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Kanda T Takai K Hohsaka T Sisido M Takaku H 《Biochemical and biophysical research communications》2000,270(3):1136-1139
Cell-free protein synthesis, driven by a crude S30 extract from Escherichia coli, has been applied to the preparation of proteins containing unnatural amino acids at specific positions. We have developed methods for inactivating tRNA(Asp) and tRNA(Phe) within a crude E. coli tRNA by an antisense treatment and for digesting most of the tRNA within the S30 extract without essential damage to the ribosomal activity. In the present study, we applied these methods to the substitution of Asp and Phe residues of the HIV-1 protease with unnatural amino acids. With 10 mM Mg(2+), the translation efficiency was higher than that with the other tested concentration, and the misreading efficiency was low. The protease mRNA was translated in the presence of an antisense DNA-treated tRNA mixture and 2-naphthylalanyl- and/or p-phenylazophenylalanyl-tRNA. The results suggest that a good portion of the translation products are substituted at all of the seven positions originally occupied by Asp or Phe. 相似文献
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Summary Specific radioactivity in three amino acid compartments was examined in broiler chicks following a flooding dose of leucine or phenylalanine. In general, specific radioactivity of leucine and phenylalanine in deproteinated plasma (SAe) and tissue (SAi) compartments, exceeded that in acylated-tRNA (SAt). In most tissues, SAe and SAi rapidly reached a similar peak level by 5 min followed by a slow decline for the next 30 minutes. Many tissues (eg. GI tract, liver, skin, and thigh) failed to maintain equilibrium between SAe and SAi over time. More metabolically active tissues, such as GI and liver had the greatest differences between these compartments. The difference between SAe and SAi for both leucine and phenylalanine were due to SAi decreasing faster than SAe, indicating dilution with unlabelled amino acids from proteolysis. Plasma and tissue specific radioactivity overestimated tRNA specific radioactivity by as much as 5 and 2.8 fold using leucine or 2.7 and 1.4 fold using phenylalanine, respectively. These data suggest that intracellular compartmentation of protein metabolism and the coupling of protein degradation and synthesis occur, in vivo. 相似文献
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The influx of amino acids into the brain of the rat in vivo: the essential compared with some non-essential amino acids 总被引:10,自引:0,他引:10
G Ba?os P M Daniel S R Moorhouse O E Pratt 《Proceedings of the Royal Society of London. Series B, Containing papers of a Biological character. Royal Society (Great Britain)》1973,183(70):59-70
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The effects of individual amino acids on the incorporation of labelled amino acids into proteins by brain homogenates 总被引:3,自引:1,他引:2
Abstract— The effects of phenylalanine and other amino acids on incorporation of several different 14C-labelled amino acids into cerebral protein were studied in brain homogenates. Excess of some amino acids had a varied effect with different 14C-labelled amino acids. Of the unlabelled-labelled amino acid combinations tested the maximal inhibition was obtained with the following: (1) phenylalanine, which inhibited the incorporation of [14C]tyrosine, and (2) leucine, which inhibited incorporation of [14C]isoleucine. In both cases the inhibition occurred principally in proteins that were recovered in the 800 g and 13,000 g sediments. Only a small degree of inhibition occurred in proteins that sedimented at 100,000 g, and no inhibition occurred in proteins of the 100,000 g supernatant. 相似文献
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Nakashima K Ishida A Yakabe Y Yamazaki M Abe H 《Bioscience, biotechnology, and biochemistry》2006,70(8):1975-1978
We examined the effects of orally administrated amino acids on myfibrillar proteolysis in food-deprived chicks. Plasma N(tau)-methylhistidine concentration, as an index of myofibrillar proteolysis, was decreased by the administration of Glu, Gly, Ala, Leu, Ile, Ser, Thr, Met, Trp, Asn, Gln, Pro, Lys and Arg but not by Asp, Val, Phe, Tyr or His to chicks. Orally administrated Cys was fatal to chicks. These results indicate that oral Glu, Gly, Ala, Leu, Ile, Ser, Thr, Met, Trp, Asn, Gln, Pro, Lys and Arg administration suppressed myofibrillar proteolysis in chicks. 相似文献