Slide 9:OK,now let's think about how these various hot zones relate to microbial life.Note the facts on this slide.Mesophiles have an optimum temperature of 20-45C.Thermophiles have an optimum temperature equal to 45-80C.Hyperthermophile have optimal temperatures greater than 80C.Note that the upper temperature limit for life may be ~150C Slide 10:This is a phylogenetic tree of life.All of the emboldened deeply branching lineages contain thermophilic microbes.This fact along with data on the physical and chemical characteristics of the early earth have led scientists to speculate that life first evolved in a high temperature environment. Slide 11:Prof.Thomas Brock really got much of the interest in thermophilic and hyperthemrophilic microbes started.He did extensive sampling in the hot springs of Yellowstone National Park and isolated many thermophilic microbes.He even isolated and made available to the world the species Thermus aguaticus.A DNA polymerase from this microbe was later used by Dr.Kerry Mullis to develop the polymerase chain reaction.Dr. Mullis received the Nobel Prize for this discovery.Unfortunately,neither the National Park Service nor Dr.Brock received any financial reward or recognition. Slide 12:Dr.Karl Stetter took the study of thermophilic microbes to another level with his "green thumb"for growing microbes and his appreciation for anaerobic microbiology.Most hyperthermophiles are strict anaerobes. Slide 13:Anaerobic microbiology requires very different techniques and equipment from that used with aerobic and facultatively anaerobic microbes.For example,anaerobic hoods (left)and anaerobic gasing stations(right)are often needed to ensure an oxygen free environment. Slides 14-19:examples of some of hyperthermophilic microbes,including the most high temperature-adapted microbes yet known. Slide 18:This slide shows the current world record holder for the upper temperature limit for life:122C.This slide shows a technique for growing this deep-sea methane producing microbe that involves high pressure as well as high temperature. Slide 19:describes a hyperthermophile that uses rocket fuel to grow!It breathes perchlorate.In other words this microbe uses perchlorate as an electron acceptor just like we breath oxygen. Slide 20:This slide outlines a highly controversial study that purported to have discovered hydrothermal vent microbes living at 250C.The flaws in the experiment(noted by Trent et al.) are indicated Slide 21:So how to microbes live at high temperature?One of the explanations is that their proteins having higher temperature limits for denaturation as shown on this plot. Slide 22:Proteins are held together by four different classes of weak bonds as indicated on this slide.You should know what these are.Proteins from thermophilic microbes use all of these weak bonds to keep their proteins more stable.Slide 9: OK, now let’s think about how these various hot zones relate to microbial life. Note the facts on this slide. Mesophiles have an optimum temperature of 20 - 45ºC. Thermophiles have an optimum temperature equal to 45 - 80ºC. Hyperthermophile have optimal temperatures greater than 80ºC. Note that the upper temperature limit for life may be ~ 150ºC Slide 10: This is a phylogenetic tree of life. All of the emboldened deeply branching lineages contain thermophilic microbes. This fact along with data on the physical and chemical characteristics of the early earth have led scientists to speculate that life first evolved in a high temperature environment. Slide 11: Prof. Thomas Brock really got much of the interest in thermophilic and hyperthemrophilic microbes started. He did extensive sampling in the hot springs of Yellowstone National Park and isolated many thermophilic microbes. He even isolated and made available to the world the species Thermus aquaticus. A DNA polymerase from this microbe was later used by Dr. Kerry Mullis to develop the polymerase chain reaction. Dr. Mullis received the Nobel Prize for this discovery. Unfortunately, neither the National Park Service nor Dr. Brock received any financial reward or recognition. Slide 12: Dr. Karl Stetter took the study of thermophilic microbes to another level with his “green thumb” for growing microbes and his appreciation for anaerobic microbiology. Most hyperthermophiles are strict anaerobes. Slide 13: Anaerobic microbiology requires very different techniques and equipment from that used with aerobic and facultatively anaerobic microbes. For example, anaerobic hoods (left) and anaerobic gasing stations (right) are often needed to ensure an oxygen free environment. Slides 14-19: examples of some of hyperthermophilic microbes, including the most high temperature-adapted microbes yet known. Slide 18: This slide shows the current world record holder for the upper temperature limit for life: 122°C. This slide shows a technique for growing this deep-sea methane producing microbe that involves high pressure as well as high temperature. Slide 19: describes a hyperthermophile that uses rocket fuel to grow! It breathes perchlorate. In other words this microbe uses perchlorate as an electron acceptor just like we breath oxygen. Slide 20: This slide outlines a highly controversial study that purported to have discovered hydrothermal vent microbes living at 250°C. The flaws in the experiment (noted by Trent et al.) are indicated. Slide 21: So how to microbes live at high temperature? One of the explanations is that their proteins having higher temperature limits for denaturation as shown on this plot. Slide 22: Proteins are held together by four different classes of weak bonds as indicated on this slide. You should know what these are. Proteins from thermophilic microbes use all of these weak bonds to keep their proteins more stable