帮忙翻译一下这篇文章,急急!!!!!!!!!!!!!!!!!!!!!!!!!!!

Mycoplasma
Mycoplasma is a genus of bacteria that lack a cell wall. Because they lack a cell wall, they are unaffected by some antibiotics such as penicillin or other beta-lactam antibiotics that target cell wall synthesis. They can be parasitic or saprotrophic. Several species are pathogenic in humans, including M. pneumoniae, which is an important cause of atypical pneumonia and other respiratory disorders, and M. genitalium, which is believed to be involved in pelvic inflammatory diseases. They may cause or contribute to some cancers.
The genus Mycoplasma is one of several genera within the class Mollicutes. Mollicutes are bacteria which have small genomes, lack a cell wall and have a low GC-content (18-40 mol%). There are over 100 recognized species of the genus Mycoplasma. Their genome size ranges from 0.58 - 1.38 megabase-pairs. Mollicutes are parasites or commensals of humans, animals (including insects), and plants; the genus Mycoplasma is by definition restricted to vertebrate hosts. Cholesterol is required for the growth of species of the genus Mycoplasma as well as certain other genera of mollicutes. Their optimum growth temperature is often the temperature of their host if warmbodied (e.g. 37 degrees Celsius in humans) or ambient temperature if the host is unable to regulate its own internal temperature. Analysis of 16S ribosomal RNA sequences as well as gene content strongly suggest that the mollicutes, including the mycoplasmas, are closely related to either the Lactobacillus or the Clostridium branch of the phylogenetic tree (Firmicutes sensu stricto).
Mycoplasmas are often found in research laboratories as contaminants in cell culture. Mycoplasmal cell culture contamination occurs due to contamination from individuals or contaminated cell culture medium ingredients. The Mycoplasma cell is usually smaller than 1 µm and they are therefore difficult to detect with a conventional microscope. Mycoplasmas may induce cellular changes, including chromosome aborations, changes in metabolism and cell growth. Severe mycoplasma infections may destroy a cell line. Detection techniques include PCR, plating on sensitive agar and staining with a DNA stain including DAPI or Hoechst.
The bacteria of the genus Mycoplasma (trivial name: mycoplasmas) and their close relatives are largely characterized by lack of a cell wall. Despite this, the shapes of these cells often conform to one of several possibilities with varying degrees of intricacy. For example, the members of the genus Spiroplasma assume an elongated helical shape without the aid of a rigid structural cell envelope. These cell shapes presumably contribute to the ability of mycoplasmas to thrive in their respective environments. M. pneumoniae cells possess an extension, the so-called 'tip-structure', protruding from the coccoid cell body. This structure is involved in adhesion to host cells, in movement along solid surfaces (gliding motility), and in cell division. M. pneumoniae cells are of small size and pleomorphic, but with a rough shape in longitudinal cross-section resembling that of a round-bottomed flask.
Mycoplasmas are unusual among bacteria in that most require sterols for the stability of their cytoplasmic membrane. Sterols are acquired from the environment, usually as cholesterol from the animal host. Mycoplasmas also generally possess a relatively small genome of 0.58-1.38 megabases, which results in drastically reduced biosynthetic capabilities and explains their dependence on a host. Additionally they use an alternate genetic code where the codon UGA is encoding for the amino acid tryptophan instead of the usual opal stop codon.
In 1898 Nocard and Roux reported the cultivation of the causative agent of contagious bovine pleuropneumonia (CBPP), which was at that time a grave and widespread disease in cattle herds. Today the disease is still endemic in Africa and Southern Europe. The disease is caused by M. mycoides subsp. mycoides SC (small-colony type), and the work of Nocard and Roux represented the first isolation of a mycoplasma species. Cultiviation was, and still is difficult because of the complex growth requirements. These researchers succeeded by inoculating a semi-permeable pouch of sterile medium with pulmonary fluid from an infected animal and depositing this pouch intraperitoneally into a live rabbit. After fifteen to twenty days, the fluid inside of the recovered pouch was opaque, indicating the growth of a microorganism. Opacitiy of the fluid was not seen in the control. This turbid broth could then be used to inoculate a second and third round and subsequently introduced into a healthy animal, causing disease. However, this did not work if the material was heated, indicating a biological agent at work. Uninoculated media in the pouch, after removal from the rabbit, could be used to grow the organism in vitro, demonstrating the possibility of cell-free cultivation and ruling out viral causes, although this was not fully appreciated at the time (Nocard and Roux, 1890). The name Mycoplasma, from the Greek mykes (fungus) and plasma (formed), was proposed in the 1950’s, replacing the term pleuropneumonia-like organisms (PPLO) referring to organisms similar to the causative agent of CBPP (Edward and Freundt, 1956). It was later found that the fungus-like growth pattern of M. mycoides is unique to that species.
This confusion about mycoplasmas and virus would surface again 50 years later when Eaton and colleagues cultured the causative agent of human primary atypical pneumonia (PAP) or 'walking pneumonia.' This agent could be grown in chicken embryos and passed through a filter that excluded normal bacteria. However, it could not be observed by high magnification light microscopy, and it caused a pneumonia that could not be treated with the antimicrobials sulphonamides and penicillin (Eaton, et al., 1945a). Eaton did consider the possibility that the disease was caused by a mycoplasma, but the agent did not grow on the standard PPLO media of the time. These observations led to the conclusion that the causative agent of PAP is a virus. Researchers at that time showed that the cultured agent could induce disease in experimentally infected cotton rats and hamsters. In spite of controversy whether the researchers had truly isolated the causative agent of PAP (based largely on the unusual immunological response of patients with PAP), in retrospect their evidence along with that of colleagues and competitors appears to have been quite conclusive (Marmion, 1990). In the early 1960's, there were reports linking Eaton's Agent to the PPLOs or mycoplasmas, well known then as parasites of cattle and rodents, due to sensitivity to antimicrobial compounds (i.e. organic gold salt) (Marmion and Goodburn, 1961). The ability to grow Eaton's Agent, now known as Mycoplasma pneumoniae, in cell free media allowed an explosion of research into what had overnight become the most medically important mycoplasma and what was to become the most studied mycoplasma.
Recent advances in molecular biology and genomics have brought the genetically simple mycoplasmas, particularly M. pneumoniae and its close relative M. genitalium, to a larger audience. The second published complete bacterial genome sequence was that of M. genitalium, which has one of the smallest genomes of free-living organisms (Fraser, et al., 1995). The M. pneumoniae genome sequence was published soon afterwards and was the first genome sequence determined by primer walking of a cosmid library instead of the whole-genome shotgun method (Himmelerich, et al., 1996). Mycoplasma genomics and proteomics continue in efforts to understand the so-called minimal cell (Hutchison and Montague, 2002), catalog the entire protein content of a cell (Regula, et al., 2000), and generally continue to take advantage of the small genome of these organisms to understand broad biological concepts.
Scientists have also been exploring an association between mycoplasma and cancer. Despite a number of interesting studies, this cancer bacteria association hasn't been clearly established, and has yet to be fully elucidated (Ning and Shou, 2004), (Tsai, et al., 1995).
The medical and agricultural importance of members of the genus Mycoplasma and related genera has led to the extensive cataloging of many of these organisms by culture, serology, and small subunit rRNA gene and whole genome sequencing. A recent focus in the sub-discipline of molecular phylogenetics has both clarified and confused certain aspects of the organization of the class Mollicutes, and while a truce of sorts has been reached, the area is still somewhat of a moving target (Johansson and Pettersson, 2002).
The name mollicutes is derived from the Latin mollis (soft) and cutes (skin), and all of these bacteria do lack a cell wall and the genetic capability to synthesize peptidoglycan. While the trivial name 'mycoplasmas' has commonly denoted all members of this class, this usage is somewhat imprecise and will not be used as such here. Despite the lack of a cell wall, Mycoplasma and relatives have been classified in the phylum Firmicutes consisting of low G+C Gram-positive bacteria such as Clostridium, Lactobacillus, and Streptococcus based on 16S rRNA gene analysis. The cultured members of Mollicutes are currently arranged into four orders: Acholeplasmatales, Anaeroplasmatales, Entomoplasmatales, and Mycoplasmatales. The order Mycoplasmatales contains a single family, Mycoplasmataceae, which contains two genera: Mycoplasma and Ureaplasma. Historically, the description of a bacterium lacking a cell wall was sufficient to classify it to the genus Mycoplasma and as such it is the oldest and largest genus of the class with about half of the class' species (107 validly described) each usually limited to a specific host and with many hosts harboring more than one species, some pathogenic and some commensal. In later studies, many of these species were found to be phylogenetically distributed among at least three separate orders. A limiting criterion for inclusion within the genus Mycoplasma is that the organism have a vertebrate host. In fact, the type species, M. mycoides , along with other significant mycoplasma species like M. capricolum, is evolutionarily more closely related to the genus Spiroplasma in the order Entomoplasmatales than to the other members of the Mycoplasma genus. This and other discrepancies will likely remain unresolved because of the extreme confusion that change could engender among the medical and agricultural communities. The remaining species in the genus Mycoplasma are divided into two non-taxonomic groups, hominis and pneumoniae, based on 16S rRNA gene sequences. The hominis group contains the phylogenetic clusters of M. bovis, M. pulmonis, and M. hominis, among others. The pneumoniae group contains the clusters of M. muris, M. fastidiosum, U. urealyticum, the currently unculturable haemotrophic mollicutes, informally referred to as haemoplasmas (recently transferred from the genera Haemobartonella and Eperythrozoon), and the M. pneumoniae cluster. This cluster contains the species (and the usual or likely host) M. alvi (bovine), M. amphoriforme (human), M. gallisepticum (avian), M. genitalium (human), M. imitans (avian), M. pirum (uncertain/human), M. testudinis (tortoises), and M. pneumoniae (human). Most if not all of these species share some otherwise unique characteristics including an attachment organelle, homologs of the M. pneumoniae cytadherence-accessory proteins, and specialized modifications of the cell-division apparatus.
A detailed analysis of the 16S rRNA genes from the order Mollicutes by Maniloff has given rise to a view of the evolution of these bacteria that includes an estimate of the time-scale for the emergence of some groups or features (Maniloff, 2002). This analysis suggests that about 600 million years ago (MYA), late in the Proterozoic era, Mollicutes branched away from the low G+C Gram-positive ancestor of the streptococci, losing their cell wall. At this time on Earth, molecular oxygen was present in the atmosphere at 1%, and the fossil record shows that multicellular marine animals had recently spread in the Cambrian explosion. One hundred million years later the requirement for sterols in the cytoplasmic membrane evolved along with the change to the alternate genetic code. Also, the ancestor of the genera Spiroplasma and Entomoplasma (primarily plant and insect pathogens) and Mycoplasma emerged at this time and would itself diverge into the Spiroplasma-Entomoplasma and Mycoplasma lineages approximately 100 million years after that. This diversity coincided with the origin of land plants 500 MYA. It appears that the calculated rate of evolution for the Mycoplasma group increased several fold about 190 MYA, soon after the appearance of vertebrates, while the Spiroplasma-Entomoplasma ancestor continued to evolve at the previously shared slower rate until about 100 MYA, when angiosperms and their associated pollinating insects appeared. Then the evolution rate of these bacteria appears to have also increased significantly. This is an attractive hypothesis, but while it tracks the emergence of several of the unusual characteristics of Mycoplasma and related organisms, it does not address the selective pressures driving their evolution, except perhaps the widespread close association of a parasite with a specific host. The advantages of a reduced genome, cell wall-less structure, and alternate genetic code remain murky.

200分之内没人会给你翻译的（机译除外）

?文能？

文章在哪里?

支原体
支原体是一种属的细菌缺乏细胞壁。因为他们缺乏细胞壁，他们不会受到一些抗生素如青霉素或其他β -内酰胺类抗生素这一目标的细胞壁合成。他们可以寄生或saprotrophic 。几个物种在人类致病，包括米，肺炎，这是一个重要原因，非典型肺炎和其他呼吸系统疾病，生殖和文字，这是被认为参与在盆腔炎。他们可能会导致或有助于某些癌症。
属支原体是其中的几个属内部的阶级mollicutes 。 mollicutes是细菌，其中有小的基因组，缺乏细胞壁有一个低的GC -内容（ 18-40 mol ％时） 。有超过100个公认的属种支原体。其基因组大小范围从0.58 -1 .38m egabase-对。 mollicutes是寄生虫或commensals人类，动物（包括昆虫） ，和植物;属支原体是根据定义，仅限于脊椎动物宿主。胆固醇是需要的增长，种支原体，以及某些其他属的mollicutes 。他们的最佳生长温度，往往是温度的东道国，如果warmbodied （如37摄氏度，在人类）或常温如果主机是无法规范其自身的内部温度。分析16核糖体RNA序列，以及基因的内容，强烈建议该mollicutes ，包括支原体，有密切的关系，无论是乳酸菌或梭菌分行的进化树（ firmicutes严格意义上） 。
支原体经常发现在研究实验室作为污染物在细胞培养。支原体细胞培养污染的发生是由于污染的个人或受污染的细胞培养基成分的药物。支原体细胞，通常小于1 μ m和因此，他们难以察觉，与传统的显微镜。支原体可引起细胞的变化，包括染色体aborations的变化，代谢及细胞的生长。严重的支原体感染，可能摧毁一个细胞系。检测技术，包括聚合酶链反应，镀上敏感的琼脂和染色的DNA染色包括dapi或Hoechst的。
细菌属支原体（小事名称：支原体）和他们的近亲，主要特点是缺乏一个细胞壁。尽管这样，形状，这些细胞往往符合一几种可能性与不同程度的复杂性。例如，成员属螺承担一细长螺旋形状没有援助的刚性结构细胞的信封。这些细胞形状假设作出贡献的能力，支原体的蓬勃发展，在各自的环境。米肺炎细胞具有延长，所谓的'秘诀结构' ，伸出由球形细胞体。这个结构是所涉及的粘附在宿主细胞，在运动沿固体表面（滑翔运动） ，并在细胞分裂。米肺炎细胞体积小和多形性，但与一个粗略的形状在纵向截面相似，即1轮-谷底瓶。
支原体是不寻常的细菌之间在这方面最需要甾醇为稳定他们的胞质膜。甾醇是由后天的环境，通常是由于胆固醇从动物宿主。支原体也普遍拥有一个相对较小的基因组0.58-1.38 megabases ，结果在急剧减少的生物合成能力，并解释他们的依赖于东道国。此外，他们使用替代遗传代码的密码子uga是编码氨基酸色氨酸而不是平常的蛋白石停止密码子。
在1898年诺卡尔和空肠Roux报道，培养病原体的牛传染性胸膜肺炎放线杆菌（ cbpp ） ，这是在当时的严重和普遍的疾病在牛群。今天，疾病仍是风土病在非洲和欧洲南部。这种疾病是造成米mycoides亚。 mycoides资深大律师（小殖民地型） ，和工作诺卡尔和空肠Roux代表首次分离的一支原体物种。 cultiviation是，现在仍然是困难的，因为复杂的增长要求。这些研究人员成功地接种一半透水袋无菌中等肺流体从受感染的动物和沉积，这袋腹腔内成为一个活兔。后15至二十天，流体内部的回收袋是不透明的，这表明增长的一个微生物。 opacitiy的流体是没有看到在控制。这肉汤混浊，然后可以用来接种第二和第三轮和随后引入一个健康的动物，造成疾病。然而，这并不工作，如果材料的加热，显示出生物制剂的工作。 uninoculated媒体，在邮袋，取出后从兔，可被用来成长的有机体，在体外，显示的可能性细胞自由种植和排除病毒的原因，虽然这是不充分体会到在时间（诺卡尔和空肠Roux ， 1890年） 。名称支原体，从希腊mykes （真菌）和等离子（形成） ，提出了在1950年的，一词取代传染性胸膜肺炎样的生物体（ pplo ）是指生物体类似病原体的cbpp （何承天和弗罗因特， 1956年） 。它后来被发现，该真菌样生长模式米mycoides是独一无二的物种。
这种混乱约支原体和病毒表面再次五十年后，当伊顿和他的同事培养的病原体的人原发性非典型肺炎（子宫颈抹片）或步行肺炎。这剂可以增加，鸡胚胎和通过过滤器，排除正常的细菌。不过，它不能所应遵守的高倍光镜，它引起了肺炎无法治疗与抗菌药物sulphonamides和青霉素（伊顿，等人， 1945a ） 。伊顿确曾考虑的可能性，即疾病所造成的一支原体，但代理人没有成长，关于标准的pplo媒体的时间。这些意见，导致得出的结论是病原体的子宫颈抹片是一种病毒。研究人员认为，时间显示，培养剂可诱导疾病的实验感染棉花大鼠和仓鼠。尽管如此，争议是否有真正的研究人员分离病原体的子宫颈抹片（主要基于不正常的免疫反应患者的子宫颈抹片） ，在回顾他们的证据，一直与同事和竞争对手似乎已相当定论（ marmion ， 1990年） 。在上世纪60年代初，有报道说，连接伊顿的代理人向pplos或支原体，人所共知，然后作为寄生虫牛和啮齿动物，由于敏感性抗菌化合物（即有机金盐） （ marmion和goodburn ， 1961年） 。能力成长伊顿的代理人，现在被称为肺炎支原体，在细胞自由媒体获准爆炸研究了什么一夜之间成为最重要的医学支原体和什么是成为研究得最多的支原体。
最近的进展，在分子生物学和基因组学研究带来了基因简单的支原体，尤其是米，肺炎和其近亲米生殖，一个更大的观众。第二次公布的细菌的完整基因组序列是分枝杆菌生殖，这是其中一个最小的基因组的自由活的生物体（弗雷泽等人， 1995年） 。该米肺炎基因组序列公布不久，并且是第一的基因序列，确定引走了一个粘粒图书馆，而是整个基因组鸟枪法（ himmelerich ，等人， 1996年） 。支原体基因组学和蛋白质组学继续在努力去理解那些所谓最小的细胞（和记和蒙塔古， 2002年） ，产品目录，整个蛋白质含量的细胞（古拉，等人， 2000年） ，和一般继续利用小基因组中这些生物体的了解广泛的生物学概念。
科学家也一直在探索的一个协会之间的支原体感染和癌症。尽管许多很有意思的研究，这种癌症的细菌协会尚未明确确立，并已尚未得到充分阐述了（宁守和， 2004年） ， （蔡瑞月等人， 1995年） 。
医疗和农业的重要性，成员属支原体及相关属导致了广泛的编目许多这些微生物的文化，血清学，和小亚基rRNA基因和整个基因组测序。近期重点在小组的纪律，分子系统学，既澄清和混乱，某些方面的组织的阶级mollicutes ，而休战的各种已经达成，该地区仍是有点一个移动的目标（约翰森和pettersson ， 2002年） 。
名称mollicutes是来自拉丁美洲树（软）和cutes （皮肤） ，以及所有这些细菌做缺乏细胞壁和遗传的能力，合成肽聚糖。而琐碎的名称'支原体'已普遍标注的所有成员这一阶层，这个用法是有点不确切的，并不会被用来作为，例如在这里。尽管缺乏一个细胞壁，支原体和亲属已被列为在该门firmicutes构成的低中G + C革兰氏阳性菌如梭菌，乳杆菌，链球菌的基础上16S rRNA基因分析。培养成员mollicutes目前正安排分为四个命令： acholeplasmatales ， anaeroplasmatales ， entomoplasmatales ， mycoplasmatales 。该命令mycoplasmatales包含一个单一的家庭， mycoplasmataceae ，其中载有两个属：支原体，溶脲脲。从历史上看，说明细菌缺乏细胞壁是足够的分类，它属支原体，正因如此，它是历史最悠久，规模最大的属类与大约半数的工人阶级的物种（ 107有效描述） ，每个通常只限于特定的主机和许多主机包藏一个以上的物种，有些致病性和一些commensal 。在稍后的研究，许多这些物种被认为phylogenetically分布在至少三个不同的命令。一个限制的标准，列入属支原体是生物体有脊椎动物宿主。事实上，在类型的物种，米mycoides ，连同其他重大支原体物种一样，米capricolum ，是进化关系更为密切属螺在该命令entomoplasmatales比对其他成员的支原体属。这和其他的差异可能会仍然悬而未决因为它的极端混乱，这种改变可能产生之间的医疗和农业社区。其余的物种属支原体分为两个非生物分类群， hominis和肺炎的基础上， 16S rRNA基因序列。该hominis组包含的系统发育群牛米，米肺，和M. hominis ，等等。该肺炎组包含集群的米老鼠，米fastidiosum ，溶脲脲原体，目前unculturable haemotrophic mollicutes ，非正式地称为haemoplasmas （最近转移到属haemobartonella和附红细胞体） ，以及米肺炎集群。这组包含的物种（和一般的或可能的主机）米alvi （牛） ，米amphoriforme （人力） ，米gallisepticum （禽流感） ，米生殖（人力） ，米imitans （禽流感） ，米。 pirum （不确定/人） ，米testudinis （龟） ，和M.肺炎（人力） 。最如果不是所有这些物种分享一些，否则特色，包括附件的细胞器，同系物的米肺炎cytadherence -配件蛋白质，和专门的修改细胞司器具。
详细分析了16 S rRNA基因从秩序mollicutes由马尼洛夫已引起了看法的演变，这些细菌，其中包括一估计的时间，规模，为出现的一些团体或功能（马尼洛夫， 2002年） 。这个分析表明，约6.0亿年前（吴妙丹） ，下旬，在古代的时代， mollicutes支远离低中G + C革兰氏阳性祖先的链球菌，失去细胞壁。在这个时候地球上，分子氧是目前在大气中在1 ％ ，和化石记录表明，多海洋动物，最近蔓延在寒武纪爆炸。一亿年后的规定，甾醇在胞质膜演变随着改变，候补遗传密码。此外，祖先的属螺和entomoplasma （主要是植物和昆虫病原体）及支原体出现在这个时候，并会本身发散到螺- entomoplasma和支原体谱系大约1.0亿年后。这种多样性的符合原产地的土地，植物500妙丹。看来，计算速度演变为支原体组增加了几倍约190妙丹后不久，出现了脊椎动物，而螺- entomoplasma的祖先不断演变，在以前的共同速度，直到约100妙丹，当被子植物和他们的相关的传粉昆虫出现。然后演变率这些细菌似乎也有显着上升。这是一个具吸引力的假说，但它的轨道的同时，出现了几个不寻常的特点，支原体和相关的有机体，它不涉及选择性的压力，驾驶他们的演变，除了或许广泛密切联系的寄生虫与特定的主机。的优势，减少了基因组，细胞壁少的结构，和候补委员的遗传代码仍然不明朗