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90646 Fmxx Weeks3e-Rev3.Qxd 90646_CH01_0001_rev3.qxd 12/3/10 1:34 PM Page 5 © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC The MicrobialNOT FOR SALE OR DISTRIBUTION World: NOT FOR SALE OR DISTRIBUTION Surprising and Stunning 1 © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION Looking Ahead Perhaps you’ve heard the saying “there are more stars in the heavens than We share our world with thousands of species of plants and animals that we can see and thou- all the grains of sand on © Jones &sands Bartlett of species Learning, of microbes LLC that we cannot see. This© microbial Jones world& Bartlett is both Learning, surprising and LLCEarth.” The same may be stunning—surprising because it contains such a wealth of different forms of life, and stunning said of microbes and NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTIONgrains of soil. Without because we scarcely understand how those life forms affect our own world. This chapter begins microbes to, for example, our trek into the microbial world with some insights into an invisible realm. take nitrogen from the air On completing this chapter, you should be able to . and transfer it to the soil • appreciate how the microbial world affects our world in such areas as agriculture, where it is essential for plant growth, we would industry, research,© Jones and the & environment; Bartlett Learning, LLC © Jonesnever & Bartlett see the diversity Learning, of LLC • provide numerousNOT examples FOR SALE of how OR microbes DISTRIBUTION contribute substantially to the qualityNOT FORplant SALE life we do,OR such DISTRIBUTION as of our lives; in this colorful tulip field. • discuss the origins of microbiology and how these origins are related to studies on spontaneous generation; •© describeJones &the Bartlett contributions Learning, of Louis LLC Pasteur and Robert Koch to© theJones development & Bartlett of Learning, LLC NOTthe scienceFOR SALE of microbiology; OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION • provide thumbnail sketches of bacteria, viruses, protozoa, and other members of the microbial world; and • understand the diversity of microbes and explain why an appreciation of micro- © Jones & Bartlettbiology Learning, encourages LLC an appreciation of life. © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION 5 © Jones & Bartlett Learning, LLC. NOT FOR SALE OR DISTRIBUTION. 90646_CH01_0001_rev3.qxd 12/3/10 1:34 PM Page 6 6 CHAPTER 1 The Microbial World: Surprising and Stunning Each year, a group of pilgrims gather in the English countryside outside the vil- © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLClage of Eyam and pay homage to the townsfolk who three and a half centuries before NOT FOR SALE OR DISTRIBUTIONgave their lives so that othersNOT might FOR live.SALE The OR pilgrims DISTRIBUTION bow their heads and remem- ber what happened that fateful year. Bubonic plague had erupted in Eyam during the spring of 1665, and before long, many had fled to the countryside. But most of the townsfolk realized that by doing © Jonesso they & Bartlett would probably Learning, spread LLC the plague to nearby communities.© Jones &They Bartlett were con- Learning, LLC NOT FORfronted SALE not only OR byDISTRIBUTION the terrible disease but also by the NOTmoral FORdilemma SALE they OR faced. DISTRIBUTION Then the village rector made a passionate plea that the remainder of the townsfolk stay, and after much soul-searching, they reluctantly decided to do so and take their chances. They marked off the village limits with a circle of stones, and the neighbor- ing villagers brought food and other supplies to the self-quarantined group. In the © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC end, 259 of Eyam’s 350 people died of the plague. NOT FOR SALE OR DISTRIBUTIONThe memorial service has a poignant momentNOT FOR as the SALE pilgrims OR join DISTRIBUTION their hands and somberly recite a poem whose roots trace to that period: Ring-a-ring of rosies © Jones & Bartlett Learning, LLC A pocketful of posies© Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION Achoo! Achoo! NOT FOR SALE OR DISTRIBUTION We all fall down. There is no laughter in the group; indeed, some are moved to tears. The ring of rosies refers to the rose-shaped splotches that surrounded the neck and shoulders of © Jonesplague & Bartlett victims. Posies Learning, were flowers LLC that people tucked into© Jones their pockets & Bartlett hoping Learning, to LLC NOT FORward offSALE the evil OR spirits. DISTRIBUTION “Achoo” refers to the fits of sneezingNOT that FOR accompany SALE plague;OR DISTRIBUTION and the last line, the saddest of all, refers to the death that claimed so many plague victims. Disease has always left people thunderstruck with terror. Before the late 1800s, how- ever, that fear was compounded by ignorance because no one was really sure what causes © Jones & Bartlett disease,Learning, much LLC less how to deal with it. As ©we Jones shall see & later Bartlett in this chapter,Learning, the answers LLC NOT FOR SALE ORwould DISTRIBUTION not start coming until the late 1800s,NOT when FOR Louis SALE Pasteur ORand RobertDISTRIBUTION Koch solid- ified the link between infectious disease and microscopic forms of life. These life forms Bacteria The domain of living include bacteria, viruses, fungi, protozoa, and other groups of organisms invisible to things that includes all the unaided eye. Many scientists refer to them as “microorganisms,” but we shall use organisms not classified as microbes © JonesArchaea & Bartlettor Eukarya. Learning, LLCthe equally acceptable and© moreJones simplified & Bartlett term “Learning,.” This LLC term was coined in 1879 by the French scientist Charles E. Sedillot. It implies any living thing that must NOT FORvirus SALEAn infectious OR DISTRIBUTIONagent NOT FOR SALE OR DISTRIBUTION consisting of DNA or RNA and be magnified to be seen. surrounded by a protein sheath; To be sure, most of us are inclined to think of disease when we think of microbes. in some cases, a membranous And this connection is probably justified because some microbes cause much misery envelope surrounds the coat. and pain. But microbes are also responsible for much that adds quality to our lives. Fungi One of the five kingdoms© JonesFor &instance, Bartlett microbes Learning, break LLCdown the remains of everything© Jones that dies& Bartlett and recycle Learning, LLC in the Whittaker classification of living organisms; composed NOTof FORthe essential SALE elementsOR DISTRIBUTION so that vital nutrients can be regenerated.NOT FOR Moreover, SALE the OR very DISTRIBUTION the molds and yeasts. air we breathe is a product of microbial chemistry because certain microbes perform protozoan (pl. protozoa) A photosynthesis (the process by which light energy is converted into chemical energy) single-celled eukaryotic organism in the vast expanses of the forests and oceans, where they generate the oxygen that that lacks a cell wall and usually sustains us. Closer to home, many species of microbes live in our mouth, skin, intes- exhibits© chemoheterotrophic Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC tines, respiratory tract, and other body systems, where they prevent the multipli- metabolism.NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION microbe (microorganism) A cation of organisms that might cause disease. Microbes are also responsible for the microscopic form of life final forms of many foods we eat, including fermented dairy products such as yogurt, including bacterial, archaeal, buttermilk, and sour cream. We shall embellish on these and other ways in which fungal, and protozoal cells. microbes influence humans and society as we begin our journey through the micro- © Jones & Bartlett Learning, LLCbial world. © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION © Jones & Bartlett Learning, LLC. NOT FOR SALE OR DISTRIBUTION. 90646_CH01_0001_rev3.qxd 12/3/10 1:34 PM Page 7 Why Microbes Matter 7 © Jones & BartlettWhy Microbes Learning, Matter LLC © Jones & Bartlett Learning, LLC NOT FORIf SALEyou took OR a pinch DISTRIBUTION of rich soil and placed it in the palmNOT of your FOR hand, SALE you would OR DISTRIBUTION come face-to-face with an estimated billion microbes—bacteria, viruses, fungi, protozoa, and numerous other microscopic forms of life, shown in FIGURE 1.1 . To appreciate the extraordinarily small size of the microbes, consider this: If you were to count the microbes in a pinch of© soil Jones at a rate & Bartlettof one per Learning, second without LLC stopping, it would take © Jones & Bartlett Learning, LLC over 33 years to completeNOT your FOR counting. SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION But we are not here to count microbes. Rather, we are here to appreciate them, and so we should ask: What are the microbes doing in the soil, and why are they there? To be sure, some are disease-causing (pathogenic) microbes, probably in transit from one living thing to another. Others, however, are probably quite benign. By their sheer num- bers, ©they Jones control & the Bartlett pathogens Learning, in the soil andLLC maintain nature’s balance© in Jones the environ- & Bartlett Learning, LLC ment.NOT Many FOR species SALE capture OR energy DISTRIBUTION from the sun and store that energyNOT in the FOR form SALEof OR DISTRIBUTION sugar molecules; to do this, they use the chemistry of photosynthesis, the same chem- istry that adds oxygen to our atmosphere.
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