英文版生物医学论文

A microorganism (also can be spelled as micro organism) or microbe is an organism that is microscopic (too small to be seen by the naked human eye). The study of microorganisms is called microbiology, a subject that began with Anton van Leeuwenhoek's discovery of microorganisms in 1675, using a microscope of his own are incredibly diverse and include bacteria, fungi, archaea, and protists, as well as some microscopic plants and animals such as plankton, and popularly-known animals such as the planarian and the amoeba. They do not include viruses and prions, which are generally classified as non-living. Most microorganisms are single-celled, or unicellular, but some multicellular organisms are microscopic, while some unicellular protists, and a bacteria called Thiomargarita namibiensis are visible to the naked live in all parts of the biosphere where there is liquid water, including hot springs, on the ocean floor, high in the atmosphere and deep inside rocks within the Earth's crust. Microorganisms are critical to nutrient recycling in ecosystems as they act as decomposers. As some microorganisms can fix nitrogen, they are a vital part of the nitrogen cycle, and recent studies indicate that airborne microbes may play a role in precipitation and weather.[1]Microbes are also exploited by people in biotechnology, both in traditional food and beverage preparation, as well as modern technologies based on genetic engineering. However, pathogenic microbes are harmful, since they invade and grow within other organisms, causing diseases that kill millions of people, other animals, and plants.更多请看

建议去网上搜搜相关杂志，一定有的。就输medical magazine,或者health magazine

中国药理学报英文版《中华临床医学杂志》英文版、《免疫学杂志》、《遗传学和分子生物学医学期刊》、《实验医学杂志》、《美国医学杂志》、 《加拿大医疗协会学报》、给你一个网址，基础医学与生物医学工程栏目里的都是发英文文章的杂志。 如果需要英文医学论文润色.可以看这个网址 医学编辑是美国人,可以提供地道的英文医学论文润色修改服务.

英语医学科研论文的格式和要求

I.格式

The International Committee of Medical Journal Editors, ICMJE)

(The Uniform Requirements for Manuscripts Submitted to Biomedical Journals, 5th Ed., 1997，URMSBJ)(国际——温哥华格式1979年创建, 2006年2月最新版)*, 一篇生物医学科研论文(以下简称"论文")应包括以下12个部分：

7. Acknowledgements

8. References

9. Legends

and Methods 10. Figures

11. Tables

12. Plates and Explanations

II.要求

1.标题

A. 标题的要求

Titles are to be written to be understood by those in your field, telling them exactly what you have done in your work.(告诉你的同行确切研究了什么)

(America)Journal of the National Cancer Institute: within 14 words.

The British Journal of Cancer: within 100 letters

China journals: Chinese within 20 words; English within 10 lexical words

要求：

(1) Short and concise(简明扼要)：Write in one line (not a sentence); not containing an active verb; not exceeding 25 words or 120-140 letters and spaces; no abbreviations or chemical symbols except those that are generally accepted, . DNA, RNA, AIDS, CT, etc.; 中文标题常见的“试论”，“浅谈”，“初探”等词在英文标题中一般不用。我国的国家标准(GB-7713-87)要求将一般英文标题的实词控制在10个词以内。例：Association between Duration of Obesity and Risk of Non-insulin-Dependent Diabetes Mellitus 肥胖期与非依赖胰岛素糖尿病之关系

(2)Informative(信息丰富)：State exactly what you want the reader to know about your paper and your work;

(3)Indexing(便于索引)：Pack as many key words or indexing terms as possible into the title without overloading it; key words not in the title will be in the abstract or can go in the "Key Words" section of the paper; key words are usually in the beginning or ending place of the title. 标题是读者检索文献的重要标识，是著录题录和索引等第二次文献的重要内容。标题中所选每一个实词必须是正确通用的术语，能提供文献检索，尽量包含关键词。要求尽量把关键词(索引词)安排在标题最前面或最后面的位置上

(4)Highlighting the head word. (突出中心词): 每条标题都有中心词，它们是能高度概括论文中心内容和主题的单词，要将其放在最显著突出的位置。中心词的内容一般是研究方法，研究对象，研究目的或效果，一般为名词，名词短语，分词短语或动名词短语。

例：Knowledge-based Technology in the Service of Health 论卫生事业中的知识技术

Cognitive Impairment and Intracranial Calcification in Chronic Hyparathyroidism 鉴别力受损与颅内钙化——甲状旁腺功能逐渐减退

美国医学写作协会(American Medical Writers Association)医学论文写作要领中对于标题的说明是：

1、Introduce the article into the scientific literature

2、Most important part of the article: the part most often read and often the only part read

3、Keep precise and brief( 85-character limit is typical)

4、Must stand alone: no abbreviations

5、Avoid: “declarative” or “headline” titles; “ Our Experience” titles; asking rhetorical questions in titles:

So start with : Effect of[explanatory variable(s) ]on [ response variable] under[conditions]”

6. 不同的医学期刊对标题的书写规则要求不同， 一般有两种形式：

1). Post-transfusion hepatitis: A report of 60 cases

2). A Successful Operation on a Pair of Female Twins With Conjoined Liver

标题中冠词的用法:

1). (The) Treatment of gram-negative shock

2). Carcinoma of the anal canal

Running title

B. 标题的结构

标题的结构一般都用名词作主干的名词短语型，这类标题结构中作为主干词的名词一般带有动词意义，有时也用完整句，以陈述句较多，偶尔也用疑问句。例：

Resolution of Adult Respiratory Distress Syndrome after Recovery from Fulminant Hepatic Failure 治疗成年人突发性肝衰竭康复后呼吸窘迫综合症

Using a Title Table to Evaluate Syncope 列表诊断晕厥

表示诊断，治疗方式或药物治疗的标题结构

这类标题中的diagnosis, treatment, therapy 等作主干的名词都带有动词意义，后跟for, in, to, with 等引导的介词短语引出病名或接受诊治的部位及所使用的药物。例：

Adjunctive Therapy with Aspirin in Vernal Conjunctivitis 用阿司匹林辅助治疗春季结膜炎

Basic Approach in the Management of Intraocular Foreign Bodies 眼内异物的基本处理方法

(药物)治疗：A治疗B(A=name of the medicine; B= name of the disease)

A in the treatment/management of B;

treatment of B with A;

use of A in the treatment of B;

A therapy/treatment of B;

【关键词】  医学英语论文； 标题写作； 修辞原则； 策略Abstract：As an important component part of a medical research paper，the English title plays a crucial role in promoting international academic exchanges. Its main functions are to summarize and reveal the subject, guide reading, and to be used for storage and retrieval. This paper mainly investigates the strategies of title writing for medical English research paper and presents four principles：focuse on subject，be accurate，be concise，be words： Medical English research paper;   Title writing;   Rhetorical principle;   Strategy人们读书看报，首先要看的是标题，题目常常能概括地反应文章的内容。题目取得好，简练又吸引人，才会引起读者的兴趣。标题“居文之首，句文之要”，被人们比喻为文章的眼睛。标题在学术论文中同样起着至关重要的作用。随着经济全球化的发展，医学界国际交流活动日趋频繁，在交流活动中起主导作用的学术期刊更加“规范化、标准化”，国内越来越多刊物须附英文标题和摘要。因此，学术论文的标题英译也越来越重要。医学论文题名具有高度概括集中反映文献主题的功能，指导读者查找文献资料的导读功能和信息储存提供编制文献检索的功能［1］。本文主要探讨医学论文英文标题写作中应遵循的主要修辞原则及表达策略，以期更好地发挥学术论文标题的功能，促进学术交流。1  突出主题原则及修辞策略    题名是论文最重要的、浓缩的信息点，是读者最先得到的直接信息，即文章的主要观点和主要论点。因此，标题应简明扼要、重点突出、反映论文主题。根据国际医学期刊编辑委员会制定的《生物医学期刊投稿的统一要求》中对文题的要求：简练和反映论文主题，英文标题应切题准确，反映文章的中心内容，便于索引，利于论文广泛流通。    好的标题不仅能起到“画龙点睛”的作用，还可以提高论文索引的利用价值。通常读者总是先浏览期刊的文章标题，在对其感兴趣后才会通读全文。因此，在标题英译时，应从以下两个方面注意修辞策略：    在信息传递上，要充分反映论文的创新内容，重要内容前置，突出中心；准确使用题名的必要结构要素来完整表达医学文献主题，在医学论文中最常见的结构类型是由研究对象、研究目的和研究方法三要素组成的题名。在表达方式上，多用名词、名词词组、动名词来表达。文字安排应结构合理、选词准确、详略得当，重要的词放在文题的起始，如association, application, determination，effect，detection，establishment等词所引导的短语都是研究的中心内容。2  准确规范原则及修辞策略    准确是修辞的基本原则，也是翻译必须遵循的原则。科技文体写作更应遵循这一原则，因为学术研究特别强调准确，不能模糊不清、模棱两可。措辞准确、表达客观、逻辑严密、行文简洁、词义明确、含义固定是科技文体所共有的文体特征［2］。医学英语除了具备以上特征外，它还有大量的专业词汇、术语以及特定的词汇结构体系、语法规则和语篇结构。因此，在医学论文题名写作时语言表达要合乎医学论文写作的规范标准。论文标题英译要在正确理解原文的基础上进行，必须忠实地传达原文的内容，保持原文的风格。具体可采取以下方法：    首先，格式要求规范。标题译文可采用首字母大写，其余的用小写（首字母缩略词全大写，专有名词的首字母大写）；也可采用标题首字母大写，其余实词首字母大写，虚词小写(4个字母以上的介词或连词的首字母大写)；排列时可根据具体学术期刊的规范分别采用居中排与左对齐的方式；书名应用斜体表示。    其次，选词应强调专业化。与其它学科的英语术语相比，医学英语术语特征相对明显，专业化是医学英语的一大特色。因此，熟知医学英语术语，选择专业词汇，避免使用通俗语是医学工作者治学严谨的表现。例如，“先天性皮肤并指畸形” 应译为“syndactyly of fingers”而不是“congenital skin webbed fingers”；“大黄”“丹参”分别为“Rhubarb”和 “Salvia miltiorrhiza”，而不是“Da Hunag” 和“Dan Shen”。另一方面，科技英语用词强调词义单一、准确，忌用多义词。根据科技英语的这一修辞特点，在英译时应用词义明确单一的词来代替词义较多的词，如用to transmit, to convert, to obtain, to insert, to consume, to absorb, application, sufficient, superior来替代常用的to send, to change, to get, to put in, to use up, to take in, use, enough, better。    此外，用词要准确。注意不使用非标准化的缩略语，应使用公认的缩略词语、代号、符号、公式等。国际上《核心医学期刊文摘》中，对缩写词的使用非常谨慎，对非公认的缩略词语，第一次出现必须先写全名，缩写附后加括号。如丙型肝炎病人：hepatitis C virus (HCV)，维甲酸：all-trans retinoic acid (ATRA)。    语言的习惯搭配也是医学论文英语标题写作特征的一种重要表现形式。在英语中，有相当数量的动词、名词、形容词都有其固定的介词搭配，在使用此类词语时一定要多加注意，以避免错误。医学英语标题多采用逻辑动宾关系的名词性组合形式，常见的搭配如：patients with, cases of, operation on, cure for, response to, effect on, research in/into/on, approach to, observation(s) of/on/in, treatment of等等。下面的标题译文很好地说明了正确使用介词搭配能有助于准确明了地反映论文的主题。    例： The acupuncture effect on left ventricular function in patients with coronary heart disease and angina pectoris （针疗对冠心病心绞痛患者左心功能状态的影响）    “影响”为中心词，但它在文中的意思为“疗效”，因为“针疗”是一种治疗疾病的方法，“针疗的疗效”可译为“acupuncture effect (on)”。“左心功能状态”是表类属的定语，应紧跟“影响”。“患者patients (with)”修饰“左心功能状态”，“冠心病心绞痛”修饰“患者”。层层修饰关系在译文中均以介词表示，译文准确而明晰。［3］3  简明有效原则及修辞策略    好的标题应是高度概括、言简意赅、便于检索。在完整、准确地概括全文内容的基础上，用尽量少的文字恰当反映所研究的范围和深度，不可夸大其词，以偏概全，也不可缩小研究范围，以偏代全。做到简明有效主要从以下两个方面着手：    在信息处理上，遵循科技写作中语言运用的最小信息差原则以谋求语言运用的最大信息量的输出和最佳交际效果，即“作者应该写的都能写出来，读者对作者所表达的意思都能读明白”［4］。    在选词用语上，文题力求语言精炼，中心词突出，一般在10个单词以内，通常不超过16个单词。标题起始处的冠词“A”“The”可以省略，但文题中间的“the”不能省。采用短语翻译题名，医学论文英语标题采取的主要短语结构有：名词+动词不定式；名词或名词短语+过去分词；现在分词短语；介词短语结构；名词或名词短语+介词短语；以动词形式开始的短语结构等。以短语形式来表达一个句子,结构言简意赅,内部组织严密,而且可以把更多的信息融于一体,使彼此的逻辑关系更明确,表达更细密,更有利于达到交际目的。    由于医学英语要求客观和精确，一些旨在加强语言感染力和宣传效果的修辞格不常见。但是，医学英语强调注重有效的语法和词汇修辞，如英语讲求结构平行对称。论文标题中并列的内容，应注意到语法结构上的对称，即名词与名词并列，动名词与动名词并列，不要混杂使用。例如：The Role of Arthroscopy in Diagnosing and the Treatment of Joint Diseases in Children（关节镜在儿童关节疾病诊治中的作用）宜改为：The Role of Arthroscopy in the Diagnosis and Treatment of Joint Diseases in Children。修改后两个动名词并列，既简化了文字，符合修辞原则，而且还更为醒目。平行结构的使用可以增强修辞效果，不仅使主题更加突出，而且还富有美感，引起读者兴趣。请看下面两个例子：例1：“Clinical, physiological, and radiological study of a new purpose-designed artificial bowel sphincter”例2：“Socioeconomic status，standard of living，and neurotic disorder”例1中3个形容词平行排列加强了语音的节奏感，也明确了与中心词的修饰关系，既美观又醒目；例2中的3个并列名词短语排列有序、结构工整、逻辑关系明确，读者能很快抓住论文的中心。4  得体原则及修辞策略    一个修辞行为的有效性，还取决于它是否合乎语体的规范，是否符合言语交际环境的规定，是否符合社会交往的礼仪，是否符合文化的习俗，是否符合双方的审美倾向。［5］如用戏曲语体撰写科技论文是不得体的。科技论文的行文要符合科技文体的特点，保持文体的严肃性，是为得体。医学论文的英语题名写作与翻译要求标题与论文的内容协调一致，包括风格的一致，语言表达应符合英语习惯。因此，在医学论文标题英译时，要考虑其语法、修辞特点，尽可能体现出英语的固有风格，避免中式英语的弊病。下面介绍几种表达得体的主要修辞策略。    英文标题的写作可以不拘一格，但应突出主题，服从英语的表达习惯，避免使用中国式的英语表达形式。比如，汉语医学论文标题中常常出现“初探”、“探讨”、“经验”、“体会”等词以示谦逊，而在国外的医学刊物中使用带有“浅谈”“初探”这类句式的题名会被认为所论述的内容没有多大参考价值，缺乏严肃性。这是因为欧美人认为科技论文应立足于事实材料，不必谦虚客套。    汉语论文主标题与副标题之间一般用破折号，而英文的主标题与副标题之间通常用冒号表示。病例数在汉语中一般放在正标题中，在英语中大多放在副标题中，如：Post transfusion hepatitis: A report of 60 cases （输血后肝炎60例报告）。    由于受汉语语法的限制和语言习惯的影响，在中文标题中常含有“……的研究”和“……的观察”等词语，题名英译时应省略“Regarding …”、“Observation(s) of …”、“Investigation of …”、“Studies on …”、“Research(es) on …”、“Some thoughts on …”、“Introduction to …”等冗余套语，使之更简洁且符合英语的表达习惯。    名词化结构较多地使用抽象名词表达动作和状态，这也是英语表达和汉语表达上的主要差别之一。在汉语中用行为动词表达的意思在英语中多转换为名词。英汉语的用词顺序有很大的不同。在汉语中，定语置于中心词之前，而在英语中，“中心词+后置定语”的结构应用非常广泛。例如：葡萄糖在体外和体内对神经细胞瘤的疗效：Effect of Glucose on Neuroblastoma in Vitro and in Vivo；心脏病患者肌酐激酶同功酶的测定：Detection of Creatine Kinase Isoenzymes Inheart Disease；严重脑外伤患者大断面骨折接骨时间选择：Timing of Osteosynthesis of Major Fracture in Patients with Severe Brain Injury。    总之，标题在论文中起着至关重要的作用。论文的标题应能准确地概括论文的内容，提纲挈领、点明主题、吸引读者、便于检索。要写好译好英文标题，作者不仅要有严谨的治学态度，还要掌握专业英语知识，熟悉医学英语文体的写作特点，熟记常用的句式结构及英语习惯表达方法，在正确理解论文主旨的基础上，力求重点突出，行文准确、规范、简洁、得体。

microorganism (also can be spelled as micro organism) or microbe is an organism that is microscopic (too small to be seen by the naked human eye). The study of microorganisms is called microbiology, a subject that began with Anton van Leeuwenhoek's discovery of microorganisms in 1675, using a microscope of his own are incredibly diverse and include bacteria, fungi, archaea, and protists, as well as some microscopic plants and animals such as plankton, and popularly-known animals such as the planarian and the amoeba. They do not include viruses and prions, which are generally classified as non-living. Most microorganisms are single-celled, or unicellular, but some multicellular organisms are microscopic, while some unicellular protists, and a bacteria called Thiomargarita namibiensis are visible to the naked live in all parts of the biosphere where there is liquid water, including hot springs, on the ocean floor, high in the atmosphere and deep inside rocks within the Earth's crust. Microorganisms are critical to nutrient recycling in ecosystems as they act as decomposers. As some microorganisms can fix nitrogen, they are a vital part of the nitrogen cycle, and recent studies indicate that airborne microbes may play a role in precipitation and are also exploited by people in biotechnology, both in traditional food and beverage preparation, as well as modern technologies based on genetic engineering. However, pathogenic microbes are harmful, since they invade and grow within other organisms, causing diseases that kill millions of people, other animals, and microorganisms were the first forms of life to develop on earth, approximately 3–4 billion years evolution was slow,and for about 3 billion years in the Precambrian eon, all organisms were microscopic. So, for most of the history of life on Earth the only form of life were , algae and fungi have been identified in amber that is 220 million years old, which shows that the morphology of microorganisms has changed little since the triassic microorganisms can reproduce rapidly and microbes such as bacteria can also freely exchange genes by conjugation, transformation and transduction between widely-divergent species.[10] This horizontal gene transfer, coupled with a high mutation rate and many other means of genetic variation, allows microorganisms to swiftly evolve (via natural selection) to survive in new environments and respond to environmental stresses. This rapid evolution is important in medicine, as it has led to the recent development of 'super-bugs' — pathogenic bacteria that are resistant to modern possibility that microorganisms might exist was discussed for many centuries before their actual discovery in the 17th century. The first ideas about microorganisms were those of the Roman scholar Marcus Terentius Varro in a book titled On Agriculture in which he warns against locating a homestead near swamps:“ …and because there are bred certain minute creatures which cannot be seen by the eyes, which float in the air and enter the body through the mouth and nose and there cause serious diseases.” This passage seems to indicate that the ancients were aware of the possibility that diseases could be spread by yet unseen The Canon of Medicine (1020), Abū Alī ibn Sīnā (Avicenna) stated that bodily secretion is contaminated by foul foreign earthly bodies before being also hypothesized that tuberculosis and other diseases might be contagious, . that they were infectious diseases, and used quarantine to limit their the Black Death bubonic plague reached al-Andalus in the 14th century, Ibn Khatima wrote that infectious diseases were caused by "contagious entities" that enter the human body. Later, in 1546, Girolamo Fracastoro proposed that epidemic diseases were caused by transferable seedlike entities that could transmit infection by direct or indirect contact, or even without contact over long these early claims about the existence of microorganisms were speculative in nature and not based on any data or science. Microorganisms were neither proven, observed, nor correctly and accurately described until the 17th century. The reason for this was that all these early inquiries lacked the most fundamental tool in order for microbiology and bacteriology to exist as a science, and that was the van Leeuwenhoek was the first person to observe microorganisms, using a microscope of his own design, thereby making him the first microbiologist. In doing so Leeuwenhoek would make one of the most important contributions to biology and open up the fields of microbiology and bacteriology. Prior to Leeuwenhoek's discovery of microorganisms in 1675, it had been a mystery as to why grapes could be turned into wine, milk into cheese, or why food would spoil. Leeuwenhoek did not make the connection between these processes and microorganisms, but using a microscope, he did establish that there were forms of life that were not visible to the naked 's discovery, along with subsequent observations by Lazzaro Spallanzani and Louis Pasteur, ended the long-held belief that life spontaneously appeared from non-living substances during the process of Spallanzani found that microorganisms could only settle in a broth if the broth was exposed to the air. He also found that boiling the broth would sterilise it and kill the microorganisms. Louis Pasteur expanded upon Spallanzani's findings by exposing boiled broths to the air, in vessels that contained a filter to prevent all particles from passing through to the growth medium, and also in vessels with no filter at all, with air being admitted via a curved tube that would not allow dust particles to come in contact with the broth. By boiling the broth beforehand, Pasteur ensured that no microorganisms survived within the broths at the beginning of his experiment. Nothing grew in the broths in the course of Pasteur's experiment. This meant that the living organisms that grew in such broths came from outside, as spores on dust, rather than spontaneously generated within the broth. Thus, Pasteur dealt the death blow to the theory of spontaneous generation and supported germ 1876, Robert Koch established that microbes can cause disease. He did this by finding that the blood of cattle who were infected with anthrax always had large numbers of Bacillus anthracis. Koch also found that he could transmit anthrax from one animal to another by taking a small sample of blood from the infected animal and injecting it into a healthy one, causing the healthy animal to become sick. He also found that he could grow the bacteria in a nutrient broth, inject it into a healthy animal, and cause illness. Based upon these experiments, he devised criteria for establishing a causal link between a microbe and a disease in what are now known as Koch's these postulates cannot be applied in all cases, they do retain historical importance in the development of scientific thought and can still be used and structureMicroorganisms can be found almost anywhere in the taxonomic organization of life on the planet. Bacteria and archaea are almost always microscopic, while a number of eukaryotes are also microscopic, including most protists, some fungi, as well as some animals and plants. Viruses are generally regarded as not living and therefore are not microbes, although the field of microbiology also encompasses the study of viruses.[edit] ProkaryotesProkaryotes are organisms that lack a cell nucleus and the other organelles found in eukaryotes. Prokaryotes are almost always unicellular, although some species such as myxobacteria can aggregate into complex structures as part of their life cycle. These organisms are divided into two groups, the archaea and the are the most diverse and abundant group of organisms on Earth. Bacteria inhabit practically all environments where some liquid water is available and the temperature is below +140 °C. They are found in sea water, soil, air, animals' gastrointestinal tracts, hot springs and even deep beneath the Earth's crust in rocks.[20] Practically all surfaces which have not been specially sterilized are covered in bacteria. The number of bacteria in the world is estimated to be around five million trillion trillion, or 5 × are practically all invisible to the naked eye, with a few extremely rare exceptions, such as Thiomargarita are unicellular organisms and lack membrane-bound organelles. Their genome is usually a single loop of DNA, although they can also harbor small pieces of DNA called plasmids. These plasmids can be transferred between cells through bacterial conjugation. Bacteria are surrounded by a cell wall, which provides strength and rigidity to their cells. They reproduce by binary fission or sometimes by budding, but do not undergo sexual reproduction. Some species form extraordinarily resilient spores, but for bacteria this is a mechanism for survival, not reproduction. Under optimal conditions bacteria can grow extremely rapidly and can double as quickly as every 10 minutes......微生物是指一切肉眼看不到或看不清楚，因而需要借助显微镜观察的微小生物。微生物包括原核微生物（如细菌）、真核微生物（如真菌、藻类和原虫）和无细胞生物（如病毒）三类。主要特性微生物最大的特点，不但在於体积微小，而且在结构上亦相当简单。由於微生物体积极之微小，故相对面积较大，物质吸收快，转化快。微生物在生长与繁殖上亦是很迅速的，而且适应性强。从寒冷的冰川到极酷热的温泉，从极高的山顶到极深的海底，微生物都能够生存。由於微生物适应性强，又容易在较短时间内积聚非常多的个体（例如10^10个/毫升的数量级），因此容易筛选并分离到突变株。容易得到微生物突变株的性质，给人类利用与开发微生物带来广阔契机，但也是导致抗药性的内在原因。微生物的代谢微生物的代谢指微生物（细胞）内发生的全部化学反应。 微生物的代谢异常旺盛，这是由於微生物的表面积与体积比很大（约是同等重量的成年人的30万倍），使它们能够迅速与外界环境进行物质交换。代谢产物 微生物在代谢过程中，会产生多种代谢产物。根据代谢产物与微生物生长繁殖的关系，可以分为初级代谢产物和次级代谢产物两类。 初级代谢产物是指微生物通过代谢活动产生的、自身生长和繁殖所必须的物质，如氨基酸、核苷酸、多糖、脂质、维生素等。在不同种类的微生物细胞中，初级代谢产物的种类基本相同。 次级代谢产物是指微生物生长到一定阶段才产生的化学结构十分复杂，对该微生物无明显生理功能，或并非是微生物生长和繁殖所必须的物质，如抗生素、毒素、激素、色素等。不同种类的微生物所产生的次级代谢产物不相同，它们可能积累在细胞内，也可能排到外环境中。代谢的调节 微生物在长期的进化过程中，形成了一整套完善的代谢调节系统，以保证证代谢活动经济而高效地进行。微生物的代谢调节主要有两种方式：酶合成的调节和酶活性的调节。 另外人工控制微生物代谢的措施包括改变微生物遗传特徵，控制生产过程中的各种条件等。主要分类微生物主要分为以下几类：（参见生物分类总表）原核微生物 细菌(Bacteria) 古菌(Archaea) 真核微生物 真菌(Fungi) 原生生物(protozoan) 藻类(algae) 无细胞生物 病毒(virus) 类病毒(virusoid) 拟病毒(viroid) 朊毒体（亦称朊病毒、蛋白质质感染性颗粒）(prion) 微生物在自然界的存在微生物在自然界中广泛存在，数目巨大。下表为一些生态环境中微生物细胞数目的估计： 密度 全球总数 海水 108~109 L-1 约1029 海洋沉积物 109 g-1 约3×1029 动物消化道 1011 g-1 约1025 地表或海底下深处 102~108 约1030 原核生物共构成全球生物量的25~50%。微生物的作用微生物与人类的生产、生活和生存息息相关。有很多食品（如酱油、醋、味精、酒、酸奶、奶酪、蘑菇）、工业品（如皮革、纺织、石化）、药品（如抗生素、疫苗、维生素、生态农药）是依赖于微生物制造的；微生物在矿产探测与开采、废物处理（如水净化、沼气发酵）等各种领域中也发挥重要作用。微生物是自然界唯一认知的固氮者（如大豆根瘤菌）与动植物残体降解者（如纤维素的降解），同时位于常见生物链的首末两端，从而完成碳、氮、硫、磷等生物质在大循环中的衔接。若没有微生物，众多生物就失去必需的营养来源、植物的纤维质残体就无法分解而无限堆积，就没有自然界当前的繁荣与秩序或人类的产生与维续。此外，微生物对地球上气候的变化也起着重要作用。许多微生物直接参与了温室气体的排放或者吸收，而也有很多微生物可以成为未来的生物燃料[1]。微生物与人类健康微生物与人类健康密切相关。多数微生物对人体是无害的。实际上，人体的外表面（如皮肤）和内表面（如肠道）生活着很多正常、有益的菌群。它们占据这些表面并产生天然的抗生素，抑制有害菌的着落与生长；它们也协助吸收或亲自制造一些人体必需的营养物质，如维生素和氨基酸。这些菌群的失调（如抗生素滥用）可以导致感染发生或营养缺失。然而另一方面，人类与动植物的疾病也有很多是由微生物引起，这些微生物叫做病原微生物(pathogenic microorganism)或病原(pathogen)。重要的人类致病微生物列于下表中。主要的人类致病微生物 疾病名称 致病原 全球感染（携带者）人数 每年新发病例数 每年死亡人数 结核 结核分枝杆菌 ~20亿人（全球三分之一人口） 881万例 (2003 [1]) 175万人 (2003 [2]) 艾滋病 人类免疫缺陷病毒 4200万人 550万例 310万人 痢疾 志贺氏菌、痢疾杆菌、大肠埃希氏杆菌等 27亿例 190万人 疟疾 疟原虫 3-5亿例 100万人 乙型肝炎 乙型肝炎病毒 1000-3000万例 100万人 麻疹 麻疹病毒 3000万例 90万人 登革热 登革病毒 2000万例 2万4千人 流感 流感病毒 几乎全部人口 300-500万例 25万人 黄热病 黄热病毒 20万例 3万人 其他经常听说的致病微生物还有：流行已经完全得到控制或消灭的天花病毒（引起天花）和脊髓灰质炎病毒（导致小儿麻痹症）；引起炭疽病的炭疽杆菌；以及近年来显现的萨斯冠状病毒（引起严重急性呼吸道综合症，又名萨斯、也俗称非典型肺炎）和可能将在人类流行的禽流感。对现代生物学研究与医学技术的贡献现代生物学的若干基础性的重大发现与理论，是在研究微生物的过程中或以微生物为实验材料与工具取得的。这些理论包括：证明DNA（脱氧核糖核酸）是遗传信息的载体（三大经典实验：肺炎球菌的转化实验、噬菌体实验、植物病毒的重组实验） DNA的半保留复制方式（双螺旋的每一条子链分别、都是复制模板） 遗传密码子的解读（64个密码子各对应20种氨基酸及终止信号的哪一种） 基因的转录调节（operon, promoter, operator, repressor, activator的概念与调节方式） 信使RNA的翻译调节（terminator） 等等……（请添加） 现在，很多常用、通用的生物学研究技术依赖于微生物，比如：分子克隆 重组蛋白在细菌或酵母中的表达 很多医学技术也依赖于微生物。比如：以病毒为载体的基因治疗