极端环境微生物

1、极端环境微生物极端环境微生物第1页Life in extreme environments Microbes that live in conditions that would kill other creatures.Microbes that Love of extremes对其它生物是极端或致死环境火星木卫二极端环境微生物第2页生活在极端自然环境中微生物是生命奇迹，它们蕴涵着生命进化历程丰富信息，代表着生命对于环境极限适应能力，是生物遗传和功效多样性最为丰富宝藏。1. 揭示生命起源与生命演化。2. 生命机制研究：说明生物多样性形成机制、生物 适应环境机制3. 提供了在地球以外其它环境寻

2、找生命依据4. 实际应用：极端微生物资源在环境保护和修复、 人类健康、生物技术等方面利用研究意义：极端环境微生物第3页极端酶（extremozymes）极端酶含有潜在应用价值嗜热酶嗜冷酶Taq DNA聚合酶从水生栖热菌(Thermusaquaticus)中分离提取嗜热酶该菌是1969年从美国黄石国家森林公园火山温泉中分离极端环境微生物第4页极端环境微生物thermophiles psychrophiles acidophiles alkophiles halophiles barophiles Microorganisms resistant to radiation极端环境微生物第5页1.

3、High temperature environments and Thermophiles1.1 background Hot springs (陆地热泉) Shallow submarine hydrothermal systems (浅海底热泉) abyssal hot vents (深海火山口) 许多热泉温度靠近或到达沸腾 火山喷气孔温度可到达150500C 海底火山热气孔温度可到达350 C极端环境微生物第6页Thomas D. Brock Brock Biology of Microorganisms Yellowstone National Park 82C 热泉发觉了细菌 水生

4、栖热菌 (Thermus aquaticus) 崭新世界、新研究领域极端环境微生物第7页在热泉处（白色）因为温度高，没有光合细菌，伴随温度降低，开始出现光合细菌，颜色变深极端环境微生物第8页old faithful erupts(忠诚喷泉) ，每次能把75001.2万加仑泉水喷向高空，水柱高达55米！滚烫热水遇冷气后又在空中凝结成白色云柱，壮观中还透出一些妩媚极端环境微生物第9页 (Left) The orange scum is bacterial in origin. New Zealand. 1999. (Right) The rusty color on the rocks of th

5、is volcanic pool is Sulfolobus solfataricus. Italy. 极端环境微生物第10页1.2 嗜热菌(Thermophiles)主要类群 To date, over 50 thermophiles are known. The most extreme is Pyrolobus fumarii, which can multiply in temperatures up to 113C. optimal temperature: 6062C: Procaryote 7073C: photosynthetic bacteria over 100C : a

6、few unusually heat-adapted Archaea called hyperthermophiles.极端环境微生物第11页极端环境微生物第12页Temperatures approaching 100 C normally denature proteins and nucleic acids, and increase the fluidity of membranes to lethal levels. Chlorophyll degrades above 75C, excluding photosynthesis极端环境微生物第13页1.3 适应高温分子适应性 How

7、 can hyperthermophiles maintain the integrity of their macromolecules at temperatures where the chemical degradation of DNA and proteins is greatly accelerated ? 细胞膜中膜脂高饱和度脂肪酸 蛋白质热稳定性 遗传物质稳定性极端环境微生物第14页2. Low temperature and cold adapted microorganisms The Majority of the Earths ecosystems are Cold

8、Environments, 90 percent of the worlds oceans are “cold” Cold polar seas and soils, Glaciers, deep-sea areas High mountains covered with snowIce and brine pools from polar regions, High altitude snow fields and other high altitude habitats, Caves, Refrigerators, Upper atmosphere极端环境微生物第15页Cold envir

9、onments极端环境微生物第16页Most of the oceans are at approximately 5 C .The poles cover significant areas and temperatures rarely exceed 0 C极端环境微生物第17页“Red snow” is common in snow fields极端环境微生物第18页C. nivalis grows in melt water It is photosynthetic and contains chlorophyll.As temperatures become extreme it p

10、roduces resistant spores which contain a photoprotective red pigment.The spores become concentrated at the snow surface.极端环境微生物第19页Bacteria within ice fissuresAs water freezes, solutes are excluded. These accumulate as small inclusions of brine.The high salt concentrations prevent freezing极端环境微生物第20

11、页2.1 嗜冷菌(psychrophiles)和耐冷菌(psychrotrophos) cold adapted microorganisms psychrophiles:终年常冷环境 最低 最适 最高温度 0 C, 15 C 20 C 05 C 20 C 20 C psychrophiles:含有温度波动环境 最低温度 最适温度 最高温度 -120 C 15 C 20 C极端环境微生物第21页微生物种类 真核生物： yeasts, fungi, algae, lichens 原核生物：Gram negative bacteria Pseudomonas, Vibrio, Achromobac

12、ter, Flavobacterium, Cytophaga 严格厌氧菌极少 鱼和食品病原菌 是海水中异样菌主要类群极端环境微生物第22页What happens to cells when water gets colder? Lipid membranes become semi-crystalline and lose integrity at low temperatures.When water freezes it makes ice crystals that are spiky and hard and destructive to cells. Also, when movements slow down, membranes tend to gel and transportation of ions across the cell membrane slows down. It is harder a