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INFECTIOUSAGENTS感染源 The concept of an infectious agent was establishedby Robert Koch in the 19th century. Although fulfillment of ‘Koch’spostulates’ became the standard for the definition of an infectious agent, theydo not apply to uncultivable organisms (e.g. Mycobacterium leprae, Tropherymawhipplei) or members of the normal human flora (e.g. Escherichia coli, Candidaspp.). The following groups of infectious agents are now recognised. 感染源的概念是由罗伯特·科赫在19世纪建立的。尽管满足科赫法则成了感染源的标准定义，他们不适用于不可培养的生物体(例如，麻风分支杆菌，Tropherymawhipplei菌)或正常人体菌落成员(例如：埃希菌属，念珠菌)。下列感染源群组是现在认可的。 Prions朊毒体 Prions are unique amongst infectious agentin that they are devoid of any nucleic acid. They appear to be transmitted by acquisitionof a normal mammalian protein (prion protein, PrPc) which is inan abnormal conformation (PrPSC, containing an excess of beta-sheetprotein); the abnormal protein inhibits the 26S proteasome, which can degrademisfolded proteins, leading to accumulation of the abnormally configured PrPSCprotein instead of normal PrPc.The result is accumulation of protein which forms amyloid in the central nervoussystem, causing a transmissible spongiform encephalopathy. 朊毒体是唯一缺少核酸的一类感染源。他们通过在一类脯乳类蛋白质(朊毒体蛋白, PrPc)的异常构象(PrPSC,包括β-蛋白质)传递获得；这种异常的的蛋白质抑制能降低蛋白质错构的26S蛋白酶体，导致异常组配的PrPSC蛋白质积累代替正常的PrPc。导致淀粉样蛋白质在中枢神经系统中积累，引起传染性海绵状脑病。 未完待续。 注：Tropheryma whipplei是一种新型细菌，暂无中文译名，与whipplei病相关。 搜索
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发表于 2015-3-9 10:50
发表于 2015-11-28 13:11
