绪论-Introduction

1、Microbiology （微生物学）Wei-Dong Lu (卢伟东） (Associated Professor)E-mail: Phone:ddress: Biological building B305要求：1，Turn off your phones;2，It would be appreciated if you donot come into the classroom after the bell had rung; 3，Dont do anything that has no relationship with what we are learnin

2、g.References: Essential Microbiology , written by Stuart Hogg(the University of Glamorgan, UK), and published by Wiley 2005. Brock Biology of Microorganisms（10, 11, 12th），M. T. Madigan et al，New Jersey, Englewood Cliffs: Prentice Hall. 微生物学（第二版）主编：沈萍，陈向东。高等教育出版社；2006.5，北京微生物学主编：张文治。高等教育出版社；2005.10微生

3、物学（第六版）主编：李阜棣。中国农业出版社；2006，北京中文期刊微生物学报微生物学通报菌物系统应用与环境微生物学报病毒学报中国食用菌生物工程进展实验生物学报食品与发酵工业生物技术参考书微生物学教程 周德庆微生物学 沈萍工业微生物学 岑沛霖Microbiology(fifth edtion) Lansing M.Prescott;John P.Harley;Donald A.KleinIn this opening chapter, we offer some answers to the following questions:What is microbiology? The histor

4、y for the research of Microbiology;Why is it such an important subject? How have we gained our present knowledge of microbiology?An agar plate with microorganisms isolated from a deep-water sponge.1. Microbe & MicrobiologyWhat is microorganism or microbe?Microbes are a diverse group of organisms tha

5、t can be divided into the viruses, unicellular groups (Archaea, Eubacteria, protista, some fungi and some chlorophyta) and a small number of organisms with a simple multicellular structure (the large fungi and chlorophyta).Most microbes cannot be seen without the aid of a microscope.不同研究学者对微生物的定义：凡是

6、肉眼看不见或看不清楚其个体的所有生物的总称。形体微小、结构简单、进化低等，只能借助光学显微镜或电子显微镜才能看清楚其个体形态的所有生物的总称。所有形体微小、单细胞或个体结构较为简单的多细胞，甚至无细胞结构的低等生物的总称What is microbiology?the science (logos) of small (micro) life (bios).the study of living things so small that they cannot be seen with the naked eye.Is that true?Bacteria neatly fit this de

7、finition, but what about fungi and algae? These two groups each contain members that are far from microscopic. On the other hand, certain animals, such as nematode worms, can be microscopic, yet are not considered to be the domain of the microbiologist. Viruses represent another special case; they a

8、re most certainly microscopic, but by most accepted definitions they are not living.Three-domain systemThe three-domain system is a biological classification introduced by Carl Woese in 1990 that divides cellular life forms into archaea, bacteria, and eukaryote domains. In particular, it emphasizes

9、the separation of prokaryotes into two groups, originally called Eubacteria (now Bacteria) and Archaebacteria (now Archaea). Woese argued that, on the basis of differences in 16S rRNA genes, these two groups and the eukaryotes each arose separately from an ancestor with poorly developed genetic mach

10、inery, often called a progenote. Woese C, Kandler O, Wheelis M (1990). Towards a natural system of organisms: proposal for the domains Archaea, Bacteria, and Eucarya. Proc Natl Acad Sci USA 87 (12): 45769. Archaea Domain - prokaryotic, no nuclear membrane, distinct biochemistry and RNA markers from

11、eubacteria, possess unique ancient evolutionary history for which they are considered some of the oldest species of organisms on Earth; traditionally classified as archaebacteria; often characterized by living in extreme environments.Halobacterium NRC-1Ferroplasma acidophilumHerminiimonas glacieiPyr

12、odictium abyssiBacteria Domain - prokaryotic, no nuclear membrane, traditionally classified as bacteria, contain all known pathogenic prokaryotic organisms, studied far more extensively than Archaea.Eukarya Domain eukaryotes, nuclear membraneKingdom Protista or protists;Kingdom Fungi or fungi;Kingdo

13、m Plantae or plants;Kingdom Animalia or animals.Microbes include：Prokaryotes（原核微生物）Non-cellular microbes(非细胞型）：virus(病毒）Bacteria （细菌）Archaea （古菌）Eukaryotes（真核微生物）Cellular microbes（细胞型）Fungi（真菌）Algea （藻类）Protozoa（原生动物）Bacteria are prokaryotes; the other microorganisms are eukaryotes. Prokaryote cells

14、 lack a nuclear membrane and membrane-bound organelles. Bacteria(细菌，广义） have been divided into eubacteria （细菌，狭义） and archaebacteria （古菌）, with the latter more closely related to eukaryote cells.Fungi include yeasts, molds, and mushrooms.Viruses are not cellular organisms; they are intra-cellular pa

15、rasites of animals, plants, or bacteria.Why is microbiology important?To get some idea of the importance of microbiology in the world today, just consider the following list of some general areas in which the expertise of a microbiologist might be used: (1) medicine (2) environmental science (3) foo

16、d and drink production(4) fundamental research (5) agriculture(6) pharmaceutical industry (7) genetic engineering.Whilst there are undoubtedly some who fear all microbes due to the association of some microbes with various human illnesses, many microbes are also responsible for numerous beneficial p

17、rocesses such as industrial fermentation (e.g. the production of alcohol, vinegar and dairy products), antibiotic production and as vehicles for cloning in higher organisms such as plants. Scientists have also exploited their knowledge of microbes to produce biotechnologically important enzymes such

18、 as Taq polymerase, reporter genes for use in other genetic systems and novel molecular biology techniques such as the yeast two-hybrid system.The development of MicrobiologyAntoni van Leeuwenhoek;Louis Pasteur;Robert Koch;Microorganisms had been on the Earth for some 4000 million years, when Antoni

19、 van Leeuwenhoek started out on his pioneering microscope work in 1673.Microorganisms were first visualized by Antoni van Leeuwenhoek (16321723), a Dutch cloth merchant and an expert lens grinder. His simple microscopes magnified up to three hundred diameters. In the eighteenth century, many people

20、still believed that living organisms could arise spontaneously from organic matterthe doctrine of abiogenesis, or spontaneous generation. Pasteur trained as a chemist, and made a lasting contribution to the science of stereochemistry before turning his attention to spoilage problems in the wine indu

21、stry. He noticed that when lactic acid was produced in wine instead of alcohol, rod-shaped bacteria were always present, as well as the expected yeast cells. This led him to believe that while the yeast produced the alcohol, the bacteria were responsible for the spoilage, and that both types of orga

22、nism had originated in the environment.In response to a call from the French Academy of Science, he carried out a series of experiments that led to the acceptance of biogenesis, the idea that life arises only from already existing life.Using his famous swan-necked flasks, he demons-trated in 1861 th

23、at as long as dust particles (and the microorganisms carried on them) were excluded, the contents would remain sterile.The first proof of the involvement of bacteria in disease and the definitive proof of the germ theory of disease came from the German Robert Koch. In 1876 Koch showed the relationsh

24、ip between the cattle disease anthrax and a bacillus which we now know as Bacillus anthracis.Koch infected healthy mice with blood from diseased cattle and sheep, and noted that the symptoms of the disease appeared in the mice, and that rod shaped bacteria could be isolated from their blood. These c

25、ould be grown in culture, where they multiplied and produced spores. Injection of healthy mice with these spores (or more bacilli) led them too to develop anthrax and once again the bacteria were isolated from their blood. These results led Koch to formalize the criteria necessary to prove a causal

26、relationship between a specific disease condition and a particular microorganism. These criteria became known as Kochs postulates, and are still in use today.Kochs postulatesKochs postulates:1, The microorganism must be present in every instance of the disease and absent from healthy individuals.2,

27、The microorganism must be capable of being isolated and grown in pure culture.3 ,When the microorganism is inoculated into a healthy host, the same disease condition must result.4, The same microorganism must be re-isolated from the experimentally infected host.柯赫定律概括如下：柯赫定律概括如下：1.1.病原微生物一定存在于病原微生物一

28、定存在于一切患病个体中，而在健一切患病个体中，而在健康的个体中不存在康的个体中不存在; ;2.2.一定能分离和纯培养所一定能分离和纯培养所怀疑的病原微生物怀疑的病原微生物; ;3.3.当分离的病原微生物接当分离的病原微生物接种健康的宿主时，一定导种健康的宿主时，一定导致相同的疾病致相同的疾病; ;4.4.相同的病原微生物一定相同的病原微生物一定再从这种发病的宿主中分再从这种发病的宿主中分离到。离到。Despite their value, it is now realised that Kochs postulates do have certain limitations. It is kn

29、own for example that certain agents responsible for causing disease (e.g. viruses, prions: see Chapter 10) cant be grown in vitro, but only in host cells. Also, the healthy animal in Postulate 3 is seldom human, so a degree of extrapolation is necessary if agent X does not cause disease in a laboratory animal,