IndexImportance of extremophilesRole of proteins in extremophilesExtreme cold - PsychrophilesExtreme heat -ThermophilesExtra salty - HalophilesPolyextremophiles Extremophiles are organisms that live in conditions that humans consider "extreme". “Extreme” environments include, but are not limited to, extreme pressure, extreme cold, intense heat, highly acidic environments, and highly saline environments. It was once believed that these conditions lacked the capacity to sustain life. Say no to plagiarism. Get a tailor-made essay on "Why Violent Video Games Shouldn't Be Banned"? Get an original essay There are three domains of life: Eukarya, Bacteria, and Archaea. Each of these domains shares characteristics with the other while having its own unique set of characteristics, and none of these domains is ancestral to the others. The most important extremophiles belong to the Archean domain. Although penguins are classified as extremophiles, the best-known extremophiles are microorganisms; The main types of extremophiles studied by scientists come from the Archaea and Bacteria domain of life. Importance of extremophiles The study of extremophiles can offer us a solid understanding of the physicochemical limitations that define life on our planet. It is hypothesized that primitive terrestrial environments were abundant in extreme conditions: most of these environments were extremely hot. This leads to the idea that extremophiles are vestiges of ancient organisms and could provide an understanding of how life emerged on Earth. Role of proteins in extremophiles Extremophiles owe much of their ability to survive in such harsh conditions to proteins. Protein folding is an essential part of the survival of all living organisms: they are necessary for all living cells to grow, function and repair themselves. RNA translation is an obligatory step in the protein production process: without translation, organisms would have no other possible way to produce proteins and therefore function. There is no fundamental set of adaptations suited to every environment. Instead, Archaea evolved separate protein functions to survive in specific environments. By understanding how protein adaptations allow organisms to survive in extreme environments, we hope to be able to understand the limits of life not only on our planet Earth, but also in other places in our Solar System. Extreme Cold - Psychophiles One type of extremophiles is called Psychrophiles. These organisms are able to survive at very low temperatures. These organisms are found in perennially cold areas, such as the deep sea, permafrost, glaciers, snowfields and polar regions. Deep ocean water has a fairly stable temperature around 2°C. However, the salt content of water in colder regions of ocean water allows water to reach temperatures as low as -12°C without freezing. In fact, microbial activity has been detected in soils frozen below -39°C. Genomics (from the study of genes), proteomics (from the study of proteins) and transcriptomics (from the study of the transcriptome, i.e. gene expression at specific levels) circumstances) studies suggest that psychrophiles have various characteristics that allow them to translate the RNA and perform protein folding under cold conditions. Under normal conditions, proteins, especially enzymes, lose activity when the temperature drops below 20°C, which is not a good situation for a cell if it needs to grow. Enzyme activity decreases at low temperatures because the average kinetic energy in the cell is low. Alow kinetic energy means that conformational movements become slower and, consequently, less efficient. Psychrophilic proteins are more flexible, so they are better able to move and change conformation. This means that psychrophilic proteins can maintain high activity even at low temperatures. In addition to this, a psychrophilic enzyme typically has 10 times greater activity than a mesophilic enzyme (at normal temperature).Extreme Heat-ThermophilesThermophiles are able to grow between 50°C and 70°C, while hyperthermophiles can grow optimally up to 105°C, with a limit between 110°C and 121°C. These organisms can be found in geothermally heated terrestrial and marine habitats, including volcanic island sediments, hydrothermal vent systems, shallow terrestrial hot springs, and deep-sea hydrothermal vents. All cells have an outer membrane that regulates what goes in and out of the cell. The cell membrane also serves to protect the internal contents of the cell from the environment. A universal component of the cell membrane is the lipid bilayer, which forms the barrier in the membrane. Because lipids are fats, they are insoluble in water. The most common class of lipid molecules found in the bilayer are phospholipids. In extremely hot conditions, the cell membranes of “normal” organisms will be more flexible – when the membrane is more flexible it can lead to cell lysis – this causes the membrane to rupture and the cell will not be able to protect itself and will die. Another fate of “normal” proteins under extreme heat is that they may undergo irreversible development, exposing hydroponic nuclei, which cause aggregation. When proteins form aggregates, they no longer function properly. In thermophiles, however, phospholipids exhibit some adaptations. Phospholipid fatty acids are longer, have more side chains, and are saturated. Increasing the number of large hydrophobic residues, disulfide bonding, and ionic interactions promote thermostability. Better support of thermophiles would prevent water molecules from penetrating inside and destabilizing the protein core (water destabilizes proteins due to its efficiency in hydrogen bonding with the macromolecule). This provides a rigid membrane, giving it a stable membrane in a hot environment. To avoid denaturation and aggregate formation, the thermophile can form heat shock proteins. When these proteins are formed, they can protect the protein from forming aggregates, they can also fold the structure of the protein, which can allow the protein to function in the cell. Extra Salty – Halophile Halophiles are salt-loving organisms that thrive in saline environments. These organisms can be found in hypersaline environments around the world, in underground salt mines, in coastal and deep-sea locations, and in artificial salt marshes. The Dead Sea and the Great Salt Lake, which are extremely salty environments, are notable examples of where halophilic organisms can be found. Sodium chloride can alter the conformation, stability and solubility of a protein, thereby affecting the protein's ability to function. Some halophilic and eukaryotic bacteria are able to prevent the entry of salts into the cell and synthesize small organic molecules, known as osmolytes, to balance the osmotic pressure that is generated when you have a region with a higher solute concentration than the others regions. Halophilic Archaea, however, absorb high concentrations of salts. For a non-halophilic organism, when salt concentrations are high, water tends to surround the ionic lattice of the salt. Therefore there is.