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“好为人师的饶 海先生”讲课 :朊病毒不是病毒 (II)
以前常常强行和人网上谈心,现在强迫别人上课起来鸟。可能是刚开学,上课成瘾了。这课题给编辑一精选,那就热闹好玩鸟。
不得不说,这讨论疯牛病的课,起到了出乎意料的效果,全民大参与,而且没人趁机骂人的。
其实最近有心写点疯牛病有关的长文,但连prion 的中文都不知道。正好李连达老师文里带出,就利用了下。其中阿拉也偷师了不少,疯牛病有关的中文词汇也不用百度了; 谢谢大家!不来这一下,还真不知有朊病毒一说。
不过讲朊病毒是病毒的人,可是要叫Stanley Pruisner 童鞋吐血疯鸟,千辛万苦发现疯牛病不是病毒引起的,是朊蛋白PrP带来的;一下就给大家和谐了。当年那可差不多要完蛋了,HHMI 停了支助,tenure 第一次没过的。
疯牛病有关的研究早期可能多是搞病毒的人在做,大家(包括Pruisner)多认为是病毒。Pruisner 的发现是推翻了病毒理论的(病毒的定义可去看黄秀清的博文)。大家查点 Pruisner的文章,传记都可看到这点。 估计这中文翻译是国内搞疯牛病和病毒的人翻的,可能是不认输也可能是便于“理解”,还有可能是怕基金没了,给翻成朊病毒。
疯牛病现在还有少数人认为是病毒引起的,比如Yale University neuropathologist Laura Manuelidis , 但他们认为朊PrP 不在这病毒中。( Manuelidis L, Yu ZX, Barquero N, Banquero N, Mullins B. "Cells infected with scrapie and Creutzfeldt-Jakob disease agents produce intracellular 25-nm virus-like particles". Proceedings of the National Academy of Sciences of the United States of America 104 (6): 1965–70.)
“朊病毒”英文是PrPSc. Sc 是scrapie, 由羊来的,羊得这病,不疯,就是痒得一塌糊涂,靠树上蹭痒痒。人得这病,不疯不痒,浑身没力,失记忆,行动失控。。。
朊 PrPSc和病毒有类似的地方,但差别也很多,从起源,发生,发展,治理都很不同。比如,朊蛋白PrP是大家都有的,一旦变了蛋白折叠,出了问题,脑子就糟了。可在正常人里,随机发生,发生后可传染。
早期几例里,有手术刀传播的,医生在不了解的情况下,给个prion disease 的人动了手术,这手术刀“消毒”后, (prion 很难用常规 消毒 ),又给个其他病人动了脑手术。。。
如果正常 prion 变了蛋白折叠,这变性了的 蛋白可像遗传因子那样。所以有称prion 是protein-based genetic element.
还有,有些人prion PrP基因有突变,较易 变蛋白PrP折叠, 容易得prion disease.
朊蛋白以前是专指prion PrP, prion PrP是最有名的朊prion. 但现在有上10个朊prion, prion 已经给变成了“新”名词(如同kinase 等),比如这篇文章有个新的prion (http://www.sciencedaily.com/releases/2010/02/100204144420.htm). 也有给生物带来好处的prion,对进化可能也有帮助。有趣的是,老年性神经疾病Alzheizmer’s, Parkinson’s, 也有开始和prion 挂钩的, 见下。(也有异议)。
当然如果科学网童鞋们,将计就计,决定坚持叫 prion朊病毒 , 也可以。就像1+1=2, 如果科学网上大家决定从此1+1=3, 1+3=2,网上 也可以玩得很爽,不是吗?网下您也 试试 这样玩 。
科学网上课,给讲课费的吗????!!!
Science 22 June 2012: Vol. 336 pp. 1511-1513
A Unifying Role for Prions in Neurodegenerative Diseases
Many neurodegenerative diseases—including Creutzfeldt-Jakob disease, Alzheimer's disease (AD), Parkinson's disease, and amyotrophic lateral sclerosis (ALS)—share two remarkable characteristics. The first is that more than 80% of cases are sporadic. The second is that although many of the disease-specific mutant proteins are expressed in embryogenesis, the inherited forms of these neurodegenerative diseases are late-onset. This suggests that some event occurs with aging that renders a disease-specific protein pathogenic. More than 20 years ago, I argued that this event involves a stochastic refolding of the etiologic protein into a misfolded infectious state known as a prion. In the past decade, there has been renewed interest in the possibility that the proteins causing neurodegeneration are all prions, which would profoundly influence the development of diagnostics and effective therapies.
(有人认同,也有人对此观点有异议)
另:“The word prion, coined in 1982 by Stanley B. Prusiner, is derived from the words protein and infection.”
PrP =Prion Protein
瞎猜:PrP = Prusiner’s Protein?
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