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1、CHAPTER 27 PROKARYOTES AND THE ORIGINS OF METABOLIC DIVERSITYSection A: The World of Prokaryotes1. Theyre (almost) everywhere! An overview of prokaryotic life2. Bacteria and archaea are the two main branches of prokaryote evolutionCopyright 2002 Pearson Education, Inc., publishing as Benjamin Cummin
2、gs1. They1. Theyre (almost) everywhere! An overview of prokaryotic lifere (almost) everywhere! An overview of prokaryotic life Prokaryotes were the earliest organisms on Earth and evolved alone for 1.5 billion years. Today, prokaryotes still dominate the biosphere. Their collective biomass outweighs
3、 all eukaryotes combined by at least tenfold.Copyright 2002 Pearson Education, Inc., publishing as Benjamin Cummings Prokaryotes are wherever there is life. Many of them thrive in habitats that are too cold, too hot, too salty, too acidic, or too alkaline for eukaryotes. The vivid reds, oranges, and
4、 yellows that paint these rocks are colonies of prokaryotes.Fig. 27.1Copyright 2002 Pearson Education, Inc., publishing as Benjamin Cummings We hear most about the minority of prokaryote species that cause serious illness. During the 14th century, a bacterial disease known as bubonic plague, spread
5、across Europe and killed about 25% of the human population. Other types of diseases caused by bacteria include tuberculosis, cholera, many sexually transmissible diseases, and certain types of food poisoning.Copyright 2002 Pearson Education, Inc., publishing as Benjamin Cummings However, most bacter
6、ia are benign or beneficial. Bacteria in our intestines produce important vitamins. Prokaryotes recycle carbon and other chemical elements between organic matter and the soil and atmosphere. Prokaryotes often live in close association among themselves and with eukaryotes in symbioticsymbiotic relati
7、onships. Mitochondria and chloroplasts evolved from prokaryotes that became residents in larger eukaryotic cells.Copyright 2002 Pearson Education, Inc., publishing as Benjamin Cummings原核生物是地球生命的基礎 光合作用 固氮 有氧的大氣層 地球的表面溫度 生物演化 生物循環 生物共生細菌的固氮 植物生長依賴固氮作用 25% 催化合成，化學肥料 15% 閃電及其他步驟 60% 細菌固氮 固氮的細菌 水稻田中的 cy
8、anobacteria 很多都不須要施肥 某些植物根瘤中的 Rhizobium （最重要的） 輪耕的重要 其他共生及自生的細菌細菌與人類 健康（腸子中的好菌、養樂多、yoghurt） 疾病醫療（抗生素 ） 形象（口臭、放屁？ ） 環境及生態（被忽略的要素 ） 文明、戰爭、瘟疫等社會大變遷 能源（以色列第一任總統、） 科技（生物技術 ） 飲食 （酸菜、日本納豆 ） 文學藝術 （林黛玉 ）Bacteria we eat發酵的黃豆：納豆Bacillus subtilisSporulation歷史上的瘟疫 黑死病（black death） Yersinia pestis 1347年起四分之三世紀中，毀
9、滅四分之三歐洲人口 文藝復興的契機？（如自然的山火？） 肺炎（tuberculosis） Mycobacterium tuberculosis 歷史上最大殺手 一億人！ 剋星居然是同樣屬於放線菌（Actinomycetes）的鏈黴菌（ Streptomyces）產生的鏈黴素（streptomycin）及 rifampicin。Bacillus anthracis(Robert Koch, 1876)Kochs Postulates: microbiological standard to demonstrate that a specific microbe is the cause of a
10、 specific disease細菌對抗細菌 抗生素 抗生素 生物所合成（並分泌），殺死或抑制起它生物的物 質；大都是二級代謝物（一級代謝的衍生物） 已知約六千種 約三分之二為鏈黴菌所產生 生產菌也會對自己的產生的抗生素敏感 抗藥性基因與合成基因在一起，一起表現 抗藥性基因擴散到它類細菌（特別是後抗生素期 的病源菌）腸子中的細菌 腸氣 胃及小腸中沒有消化吸收的醣 Raffinose, stachyose, verbascose （豆類中豐富） 在大腸中被細菌發酵，產生腸氣 抑制其他細菌 酸菜、酸奶、優酪乳（yoghurt）、養樂多 Probiotics Lactobacillus compe
11、titive exclusion歷史性契機 第一次世界大戰英國火藥原料 acetone 危機 俄裔猶太移民Chaim Weizmann （Manchester大學） Clostridium acetobutylicus 發酵 acetone 1917年Balfour宣言：巴列斯坦為猶太人建國之地 三十年後以色列建國，Weizmann 成為第一任總 統。 今日Weizmann InstituteBacterial insecticideBacillus thuringiensisToxin: spore crystal proteins扭轉歷史的細菌 威力強過槍炮 傷寒菌 Rickettsia
12、prowazekii (紀念兩位因研究喪生的科 學家 Ricketts 及 Prowazek） 瓦解拿破崙大軍 1526年法國圍攻 Naples 失敗 1566年德國放棄進攻奧圖曼帝國 1812年拿破崙遠征俄國大敗（最慘）這方面有趣的讀物Power Unseen(Dixon, B. 1994) 以歷史或時事為例子說明微生物的與人類之間的密切關係The outer reaches of life(Postgate， 1994) 生動地描述生活在極端環境的微生物肺結核之戰（絲路）抗生素發展史事演化之舞（Microcosmos）（Margulies 與 Sagan 著，王文祥譯，1995，天下）提出
13、了生命共生理論，認為地球上所有生命 形式的根基就是細菌。瘟疫與人（Plagues and Peoples）（McNeill著，楊玉齡譯，1997）傳染病放到歷史的詮釋領域裡，審視傳染病在歷史所扮演的 角色槍炮、病菌與鋼鐵 (Guns, Germs and Steel)（Diamond著，王道還、廖月娟 譯，時報，1998）槍炮、病菌與鋼鐵是怎樣成為族群鬥爭的利 器 Modern prokaryotes are diverse in structure and in metabolism. About 5,000 speciesspecies of prokaryotes are known,
14、but estimates of actual prokaryotic diversity range from about 400,000 to 4 million species.Copyright 2002 Pearson Education, Inc., publishing as Benjamin Cummings2. Bacteria and archaea are the two main branches of prokaryote evolution2. Bacteria and archaea are the two main branches of prokaryote
15、evolution Current taxonomy recognizes two prokaryotic domainsdomains: domain BacteriaBacteria and domain ArchaeaArchaea. Bacteria and archaea diverged so early in evolution and are so fundamentally different. The archaea inhabit extreme environments and differ from bacteria in many key structural, b
16、iochemical, and geneticgenetic characteristics.Copyright 2002 Pearson Education, Inc., publishing as Benjamin CummingsSection B: The Structure, Function, and Reproduction of Prokaryotes1. Nearly all prokaryotes have a cell wall external to the plasma membrane2. Many prokaryotes are motile3. The cellular and genomic organization of pr
