华中农业微生物学第一章英文版

1、Microorganisms and MicrobiologyChapter 1 Chapter outline1.1 What is a microbe?1.2 The importance of Microbiology1.3 Microbes in our lives1.4 The history of microbiology1.5 Important events in the development of microbiologyConcepts Microorganisms are responsible for many of the changes observed in o

2、rganic and inorganic matter (e.g., fermentation and the carbon, nitrogen and sulfur cycles that occurred in nature. The development of microbiology as a scientific discipline has depended on the availability of the microscope and the ability to isolate and grow pure cultures of microorganisms. Micro

3、biology is a large discipline, which has a great impact on other areas of biology and general human welfareThe word microbe (microorganism) is used to describe an organism that is so small that can not be seen without the use of a microscope. Viruses, bacteria, fungi, protozoa and some algae are all

4、 included in this category.1.1 What is a microbe? Our world is populated by invisible creatures too small to be seen with the unaided eye. These life forms, the microbes or microorganisms, may be seen only by magnifying their image with a microscope. Microbial worldOrganisms (living)Infectious agent

5、s (non-living)Prokaryotes (unicellular)eukaryotesvirusesviroidsprionsEubacteriaArchaeaAlgae (unicellular or multicellular)Fungi (unicellular or multicellular)Protozoa (unicellular)Other (multicellular organisms)Most of the bacteria, protozoa, and fungi are single-celled microorganisms, and even the

6、multicelled microbes do not have a great range of cell types. Viruses are not even cells, just genetic material surrounded by a protein coat and incapable of independent existence.The size and cell type of microbes MicrobeApproximate range of sizes Cell type Viruses 0.01-0.25m Acellular Bacteria 0.1

7、-10m Prokaryote Fungi 2m-1m Eukaryote Protozoa 2-1000m Eukaryote Algae 1m-several meters EukaryoteThe size and cell type of microbesMicrobes impinge on all aspects of life, just a few of these are listed below:The environmentMedicineFoodBiotechnologyResearch1.2 The importance of microbiology The env

8、ironment Medicine Food Biotechnology ResearchPress here to continue Microbes are responsible for the geochemical cycles. They are found in association with plants in symbiotic relationships. Some microbes are devastating plant pathogens, but others may act as biological control agents against diseas

9、es.The disease-causing ability of some microbes is well known. However, microorganisms have also provided us with the means of their control in the form of antibiotics and other medically important drugs. Microbes have been used to produce food, from brewing and wine making, through cheese productio

10、n and bread making, to the manufacture of soy sauce. But microbes are also responsible for food spoilage.Traditionally microbes have been used to synthesize important chemicals. The advent of genetic engineering techniques has led to the cloning of polypeptides into microbes.Microbes have been used

11、as model organisms for the investigation of biochemical and genetical processes. Millions of copies of the same single cell can be produced very quickly and give plenty of homogeneous experimental material. Most people have no ethical objections to experiments with these microorganisms.1.3 Microbes

12、in our lives Microorganisms as Disease Agents Microorganisms and Agriculture Microorganisms and the Food Industry Microorganisms, Energy, and the Environment Microorganisms and the Future Branches of MicrobiologyBacteriologyProtozoologyParasitologyMicrobial MorphologyMycologyVirologyPhycology or Alg

13、ologyMicrobial physiologyMicrobial taxonomyMicrobial geneticsMolecular biologyMicrobial ecologyThe future of microbiology is brightThe future of microbiology is brightMicrobiology is one of the most rewarding of professions, because it gives its practitioners the opportunity to be in contact with al

14、l the other natural science and thus to contribute in many different ways to the betterment of human life.1.4 The history of microbiologyIn the field of observation, chance favors only prepared minds. - Louis Pasteur The discovery of microorganismsThe spontaneous generation conflictThe recognition o

15、f microbial role in diseaseThe discovery of microbial effects on organic and inorganic matterThe development of microbiology in this centuryThe discovery of microorganismsThe first person to accurately observe and describe microorganismsAntony van Leeuwenhock (1632-1723)The first person to observe a

16、nd describe microorganisms The first person to observe and describe microorganisms was the amateur microscopist Antony van leeuwenhoek was the amateur microscopist Antony van leeuwenhoek of Delft, Holland.of Delft, Holland.Leeuwenhock made his simple, single-lens microscope which could amplify the o

17、bject being viewed 50 300 times. Between 1673-1723, he wrote a series of letters to the Royal Society of London describing the microbes he observed from the samples of rainwater, and humam mouth.Leeuwenhoeks drawings of bacteria from the human mouth.A drawing of one of the microscopes showing the le

18、ns a; mounting pin b; and focusing screws c and d.lensObject being viewedadjustingscrewsPasteurs contributions:Louis Pasteur working in his laboratoryLouis Pasteur (1822 1895) Pasteur (1857) demonstrated that lactic acid fermentation is due to the activity of micro-organisms Pasteur (1861) conflict

19、over spontaneous generation birth of microbiology as a science Pasteur (1881) developed anthrax vaccine Pasteurization Spontaneous generation that living organisms could develop from nonliving or decomposing matter.The spontaneous generation conflictPasteurs swan neck flasks used in his experiments

20、on the spontaneous generation of microorganismsConclusion:Microorganisms are not spontaneously generated from inanimate matter, but are produced by other microorganismsRobert Koch in his laboratoryThe recognition of microbial role in diseaseRobert Koch (1843 1910)Kochs demonstration of special organ

21、isms cause special diseases Kochs postulates The microorganisms must be present in every case of the disease but absent from healthy organisms. The suspected microorganisms must be isolated and grown in a pure culture. The disease must result when the isolated microorganisms is inoculated into a hea

22、lthy host. The same microorganisms must be isolated again from the diseased hostThe Golden age of microbiology Koch and pure cultures Fermentation and Pasteurization Germ theory of disease VaccinationThe discovery of microbial effects on organic and inorganic matter The Russian microbiologist Winogr

23、asky discovered that soil bacteria could oxidize iron, sulfur and ammonia to obtain energy, and also isolated nitrogenfixing bacteria. Beijerinck made fundamental contributions to microbial ecology. He isolated Azotobacter and Rhizobium.Alexander Fleming (1881-1955)Sir Alexander Fleming discovered t

24、he antibiotic penicillin. He had the insight to recognize the significance of the inhibition of bacterial growth in the vicinity of a fungal contaminant.Date Microbiological History1676 Leeuwenhoek discovers animalcules Pasteur shows that lactic acid fermentation is due to a microorganism Pasteur sh

25、ows that microorganisms do not arise by spontaneous generation1867 Lister publishes his work on antiseptic surgery1869 Miescher discovers nucleic acids1876-1877 Koch demonstrates that anthrax is caused by Bacillus anthracis Laveran discovers Plasmodium, the cause of malaria1881 Koch cultures bacteri

26、a on gelatin Pasteur develops anthrax vaccine1.5 Important events in the development of microbiology1884 Kochs postulates first published Metchnikoff describes phagocytosis Gram stain developed1887 Petri dish (plate) developed by Richard Petri Beijerinck isolates root nodule bacteria Beijerinck prov

27、es that a virus particle causes the tobacco mosaic disease1921 Fleming discovers lysozyme1923 First edition of Bergeys Manual1928 Griffith discovers bacterial transformation1929 Fleming discovers penicillin Ruska develops first transmission electron microscope1935 Stanley crystallizes the tobacco mo

28、saic virus Avery shows that DNA carries information during transformation Waksman discovers streptomycin Watson and Crick propose the double helix structure for DNA1961-1966 Cohen et al use plasmid vectors to clone genes in bacteria1980 Development of the scanning tunneling microscope1983-1984 The p

29、olymerase chain reaction developed by Mullis1990 First human gene-therapy testing begun Discovery of Thiomargarita namibiensis, the largest known bacterium Escherichia coli genome sequenced Discovery that Vibrio cholerae has two separate 1944 chromosomes 1.How did Pasteurs famous experiment defeat t

30、he theory of spontaneous generation? 2.How can Kochs postulates prove cause and effect in a disease? 3.Who was the first person to use solid culture media in microbiology? What advantages do solid media offer for the culture of microorganisms?REVIEW QUESTIONS: 4.What is the enrichment culture techni

31、que and why was it a useful new method in microbiology? 5.When and how Alexander Fleming discovered antibiotics?1. Pasteurs experiments on spontaneous generation were of enormous importance for the advance of microbiology, having an impact on the methodology of microbiology, ideas on (he origin of life, and the preservation of food,to name just a few. Explain briefly how the impact of his experiments was felt on each of the topics listed.APPLICATION QUESTIONS: 2.