[农学]微生物学kejian09.pdf

Microbial Ecology 第九章微生物生态 What does microbial ecology study? Microbes on the Earth Live in every corner the largest single mass of life inside of eukaryotic cells 真核细胞 at temperatures of 100oC in the presence of toxic metals like copper 铜or mercury 汞 at pHs ~2.0 and ~11.0 down to 3.5 km below the earths surface in saturated salt solutions at 0oC “ Microbes should have evolved to utilize any niche meeting the minimal physical and chemical requirements” Lifespan of Life on Earth Importance of Microbes Microbes in the ocean affect the weather by absorbing energy to increase oceans’ temp. Without microbes life on earth could not exist. Remain the predominate life form on the planet Terminology 术语 Microflora 微生物区系 Normal flora 正常菌群 Microorganisms that normally reside on or in the body total = 1X1014 Do not produce disease under normal conditions Microbial antagonism 拮抗作用: Normal flora inhibits the overgrowth by pathogens 病原体 “Microenvironments” or “Microhabitats” 微环境 Small spaces or locations within the Earths ecosystem - different environmental factors Essentially the entire world is composed of microenvironments. A microenvironment situation in the soil 土壤中的微环境 腐殖质 Extremophiles 极端生物 organisms that exist at the extremes of the usual spectrum of life as we know it. Most are microscopic and present a wide range of diversity in adaptation and survival. not only tolerate; they in many cases, require one or more extremes in order to reproduce. Extremophiles Can Survive: 极端生物可生存的环境 113 to 200℃ -15 ℃ pH 0.0 pH 11 1200 atmospheres气压 0% oxygen 20-4- million years dormancy休眠 2 ½ years in space, etc This figure is designed to illustrate