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  • lesson content

    Can a be only ?
    ::只能是吗?

    No, a virus must have a genome of some type. But a prion is only protein, meaning there is no . How is this even possible? Obviously a prion is not living, though they can be very dangerous.
    ::不,病毒必须具有某种基因组。但棱皮只有蛋白质,这意味着没有。这怎么可能?很显然,棱皮没有生命,尽管非常危险。

    Prions and Viroids
    ::棱镜和机器人体

    Some subviral particles can also cause disease. A prion, short for proteinaceous infectious particle, is a type of infectious agent made only of protein. American neurologist and biochemist Stanley B. Prusiner was awarded the in physiology or medicine in 1997 for his discovery of prions. Prions cause a number of diseases in different , including bovine spongiform encephalopathy (BSE) in cattle (shown in  Figure ), scrapie in sheep, Kuru and Creutzfeldt-Jakob disease (CJD) in humans, and chronic wasting disease (CWD) in elk and deer.  All known prion diseases affect the structure of either the brain or other nervous tissue , and all are untreatable and fatal.
    ::某些次病毒粒子也会引起疾病。蛋白质传染性粒子的短片是一种仅由蛋白质制成的传染性制剂。美国神经学家和生物化学家斯坦利·普鲁西纳1997年因发现皮肤而获得生理学或医学学或医学学的奖赏。他发现一些不同的疾病,包括牛牛(图示)中的牛海绵状脑炎病(BSE ) 、 绵羊、 库鲁和克赖茨费尔特-雅各布病(CJD ) 、 鹿和鹿的慢性消瘦病(CWD ) 。 所有已知的脊髓疾病都会影响大脑或其他神经组织的结构,所有疾病都是不可治愈和致命的。

    lesson content

    Microscopic plaques or "holes" are characteristic of prion-affected nervous tissue, such as in the brain of this cow. The holes cause the tissue to develop a spongy (spongiform) appearance. Such massive cell death in the nervous system affects the ability of the infected animal to stand or move around.
    ::微孔或“孔”是受皮子影响的神经组织的特点,例如,在母牛的大脑中。洞使组织形成海绵形(海绵形)外观。神经系统中的这种大规模细胞死亡会影响受感染动物站立或移动的能力。

    Creutzfeldt-Jakob Disease
    ::Creuttzfeldt-Jakob疾病

    CJD is a very rare disease that causes dementia, memory loss, personality changes, hallucinations, and muscle tremors. The CJD prion is dangerous because it causes normal brain proteins to refold into an abnormal shape. The number of misfolded protein molecules eventually gets very large. They interfere with normal function, leading to cell death and, eventually, the death of the patient.
    ::CJD是一种非常罕见的疾病,它导致痴呆、记忆丧失、人格改变、幻觉和肌肉震颤。 CJD Prion非常危险,因为它导致正常的脑蛋白质折叠成异常的形状。 错误的蛋白分子数量最终会变得非常大。 它们会干扰正常功能,导致细胞死亡,并最终导致病人死亡。

    Usually, there is a very long incubation period for the disease; people do not usually become ill until late . However, in the last 15 years there have been several cases of adults younger than 30 getting CJD, mostly in Great Britain. This new form of CJD has been called variant CJD or vCJD. Scientists think that the people who contracted vCJD did so by eating the tissues of cattle infected with BSE. There was a large outbreak of BSE (see above) in the United in the early 1990s. During this time, scientist believe that many people may have been exposed to BSE infected foodstuffs, such as meat, , and nervous tissue.
    ::通常,该疾病孕育期很长;人们通常直到晚期才会生病。然而,在过去15年中,有几例30岁以下成年人获得青蒿素综合症(CJD)的病例,大部分在大不列颠。这种新型的青蒿素综合征(CJD)被称为变体CJD或VCJD。科学家认为,感染青蒿素综合征(VCJD)的人是食用感染BSE的牛组织。在1990年代初期,美国爆发了大规模BSE(见上文)。在此期间,科学家认为许多人可能接触过BSE感染的食品,如肉类、和神经组织。

    Viroids
    ::无体机器人

    Viroids are plant that consist of a very short stretch of circular, single-stranded that does not have a protein coat. They are essentially strands of naked RNA. The smallest viroid discovered so far is 220 nucleotides long. In comparison, the genome of the smallest known viruses capable of causing an infection are around 2,000 bases in size.
    ::仿生体是由极短的圆环、单板、没有蛋白质大衣的植物组成。它们基本上是裸体RNA的一小片。到目前为止,发现的最小的类固醇为220 核糖核酸。相比之下,能够造成感染的已知最小病毒的基因组面积约为2,000个基数。

    Viroids were discovered and given their name by an American plant pathologist, Theodor O. Diener, in 1971. Viroid RNA does not code for any known protein. They are usually transmitted by seed or pollen . Infected plants can show distorted growth. The first viroid to be identified was the Potato spindle tuber viroid (PSTVd). About 33 of viroids have been identified.
    ::1971年,美国植物病理学家Theodor O. Diener发现并说出了机器人的名字。 " 机器人RNA " 不对任何已知蛋白质进行编码,通常由种子或花粉传播,感染的植物可以显示扭曲的生长。第一种被识别为马铃薯脊椎管象机器人(PSTVd)的病毒。发现了大约33种类固醇。

    Controlling Prions
    ::控控引号

    Prions are infectious by the effect they have on normal versions of proteins. Therefore, deactivating prions involves denaturation of their protein structure. Denaturation is a type of chemical change that changes the shape of a molecule. Once denatured, the prion cannot cause abnormal folding of normal proteins. Prions, however, are quite resistant to denaturation by , heat, radiation, and formaldehyde treatments, but their infectivity can be reduced by such treatments. However, prions can be denatured by exposing them to temperatures of 134 degrees Celsius for 18 minutes in an autoclave. Ozone sterilization is currently being studied as a potential method for prion deactivation.
    ::粒子会因其对正常蛋白质的效应而感染。 因此, 脱活性粒子会使其蛋白质结构衰减。 减肥是一种改变分子形状的化学变化类型。 一旦变色, 粒子不会引起正常蛋白的异常折叠。 但是, 粒子非常耐受热、 辐射和甲状腺治疗的衰减, 但这种治疗可以降低它们的感染性。 但是, 将它们暴露在高压板内, 温度为134摄氏度, 持续18分钟。 目前正在研究对臭氧进行消毒, 以作为解除其作用的潜在方法。

    Summary
    ::摘要

    • Viroids are plant pathogens that consist of a very short stretch of circular, single-stranded RNA that does not have a protein coat. They are essentially strands of naked RNA. They are much smaller than viruses.
      ::机器人是植物病原体,由极短的圆形、单刃RNA组成,没有蛋白外衣,基本上是赤裸的RNA片段,比病毒小得多。
    • Prions are protein particles that can cause other proteins to form abnormal shapes, which causes disease.
      ::棱镜是蛋白质粒子,可导致其他蛋白质形成异常形状,导致疾病。

    Review
    ::回顾

    1. How do viroids and viruses differ?
      ::机器人和病毒有何不同?
    2. What is a prion?
      ::什么是棱镜?