Is E coli an extremophile

Labor Journal 2018-06

| 6/2018 70 BOOK ET AL. How extreme can environments and environmental influences be so that life still has a chance? - And what are the benefits for us from these adjustments? Andreas Stolz, microbiologist and author of the book ExtremophileMikroorganismen: from adaptation to application, gives us insights into the world of microorganisms. Right at the beginning he makes it clear that extreme habitats can be seen in relative terms: while we describe an ambient temperature of eighty degrees Celsius as extremely warm, an organism that is adapted to these high temperatures would be our average temperature feel extremely cold. From hyperthermophilic to psychrophilic, from acidophilic to alkaliphilic and from halophilic and piezophilic to radiation resistance; A separate small chapter is devoted to each of these areas. The chapters are all structured the same way. This simplifies reading and is also useful for looking up later. First of all, the author describes the respective habitats in each chapter. For example, the reader learns that in the deep sea there are hydrothermal springs with water up to 350 degrees Celsius, the African soda lakes are the most intensively investigated of all alkaline biotopes and the river “Rio Tinto” in Spain over a length of 100 kilometers pH -Values ​​between 1.5 and 2.1. A plus point of reading: Andreas Stolz also shows corresponding color photos of the extreme habitats. Immediately afterwards, Stolz goes into the microorganisms. Archaea, Bacteria and Eukarya are each discussed separately. Electron microscopic and light microscopic images also loosen up the text. A salt-loving archaeon, the Haloquadratum walsbyi, is particularly eye-catching. As the name suggests, it is not only salt-loving (halos = salt), but also square (quadratum = square). An unusual shape, which, however, leads to a high surface-to-volume ratio and thus could facilitate the uptake of nutrients from the nutrient-poor biotope - that is at least the common assumption. Recreate destroyed DNA ... Even if not all adaptation strategies have been clarified by far, it is still exciting to read what nature came up with. For example, there is an mRNA that indirectly functions as a thermometer. This mR-NA codes for a cold shock protein and is more stable at cooler temperatures than at body temperature. In this way, more of the required cold shock protein is automatically synthesized when it is cold. The high repairability of Deinococcus radiodurans is also remarkable. The microbe survives a radiation dose of more than 4000 gray (for humans an acute whole-body radiation of more than four gray is fatal). After the DNA has been completely destroyed by γ radiation, the bacterium can completely recreate it within three to four hours. Often the microorganisms are not only adapted to one extreme, but to a combination of extreme conditions. Radiation-resistant bacteria such as Deinococcus radiodurans, for example, are often quite insensitive to dehydration at the same time. And unicellular red algae (Cyanidium caldarium and Galdiera sulphuraria) grow at an extremely acidic pH value of 0.05 and are at the same time tolerant of an increased salt concentration, high temperatures and even of hostile heavy metal concentrations. Individual examples show how extreme the living conditions can actually be: According to the current state of knowledge, individual microorganisms can still grow at temperatures from -15 degrees Celsius (for example Planococcus halocryophilus Or1) to 122 degrees Celsius (for example Methanopyrus kandleri) multiply. Growth is also possible in a very acidic environment (such as Cyanidium caldarium) and a very basic environment (such as Bacillis marmarensis at pH 12.5). Viable, halophilic microbes were also isolated from salt deposits that arose as a result of the drying up of prehistoric seas. But it's not just about adapting the microorganisms. Andreas Stolz is also interested in the potential uses of the adapted microorganisms. As a working group leader at the Stuttgart Institute for Microorganisms, he focuses his research on the extraction of “valuable substances” from bacteria (L-phenylalanine, L-tryptophan, etc.), mainly from genetically modified E. coli. ... and win gold. The use of extremophilic microorganisms is of particular interest for laboratories and large-scale industry: For example, ß-galactosidase from a psychrophilic (cold-loving) bacterium is used in the production of lactose-free milk. As a result, the lactose hydrolyzes at low temperatures and there are no undesirable changes in taste, which often occur after heating. Proudly lists many of the industrial applications that already exist. Including less known strategies, such as the use for gold mining. After all: five percent of the gold extracted worldwide is produced with the help of bio-oxidation by thermophilic or acidophilic and mesophilic microorganisms. Although Extremophile Microorganisms: From Adaptation to Application is a textbook, it is entertaining read - and not just for microbiologists. Thanks to the relatively short chapters and sections, the reader receives the information in easily digestible nibbles. In addition, pride not only strings together knowledge, but also explains many facts, also with the help of understandable, colored illustrations. In general, the many illustrations and photos loosen up the text. The reviewer found the electron microscopic images of the bacteria and archaea, which one actually gets to see, particularly exciting. Darja Henseler Microorganisms are true artists of adaptation - the author Andreas Stolz presents a few examples in his textbook, which is much more entertaining reading than initially assumed. Extreme microorganisms Andreas Stolz Extremophile microorganisms: from adaptation to application Verlag Springer Spektrum (2017) Language: German, 188 pages Price: 34.99 euros (paperback)

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