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  • Figure: 04-34 Caption: Pseudopeptidoglycan and S-layers. (a) Structure of pseudopeptidoglycan, the cell wall polymer of Methanobacterium species. Note the resemblance to the structure of peptidoglycan shown in Figure 4.30, especially the peptide cross-links, in this case between N -acetyltalosaminuronic acid (NAT) residues instead of muramic acid residues. NAG, N -Acetylglucosamine.

Extremophiles imp. 1 Presentation Transcript

  • 1. EXTREMOPHILESNATURE’S ULTIMATE SURVIVORS
  • 2. EXTREMOPHILESI. What are they?II. Types of ExtremophilesIII. Extreme ProkaryotesIV. Extreme EukaryotesV. Extreme VirusesVI. Evolution of ExtremophilesVII. Biotechnological UsesVIII. Industrial UsesIX. Extraterrestrial Extremophiles?
  • 3. What are Extremophiles?Extremophiles are microorganisms— whether viruses, prokaryotes, or eukaryotes— thatsurvive under harsh environmental conditions that can include atypical temperature, pH, salinity, pressure, nutrient, oxic, water, and radiation levels
  • 4. Types of ExtremophilesTypes of Extremophiles
  • 5. Types of ExtremophilesOther types include: Barophiles -survive under high pressure levels, especially in deep sea vents Osmophiles –survive in high sugar environments Xerophiles -survive in hot deserts where water is scarce Anaerobes -survive in habitats lacking oxygen Microaerophiles -survive under low-oxygen conditions only Endoliths –dwell in rocks and caves Toxitolerants -organisms able to withstand high levels of damaging agents. For example, living in water saturated with benzene, or in the water-core of a nuclear reactor
  • 6. Surviving the Extremes
  • 7. EXTREME PROKARYOTES Hyperthermophiles -Members of domains Bacteria and Archaea -Held by many scientists to have been the earliest organisms -Early earth was excessively hot, so these organisms would have been able to
  • 8. Morphology of Hyperthermophiles-Heat stable proteins that have more hydrophobic interiors, which prevents unfolding or denaturation at higher temperatures-Have chaperonin proteins that maintain folding-Monolayer membranes of dibiphytanyl tetraethers, consisting of saturated fatty acids which confer rigidity, preventing them from being degraded in high temperatures-Have a variety of DNA-preserving substances that reduce mutations and damage to nucleic acids, such as reverse DNA gyrase The red on these rocks and Sac7d is produced by-They can live without sunlight or organic Sulfolobus solfataricus, carbon as food, and instead survive on near Naples, Italy sulfur, hydrogen, and other materials that other organisms cannot metabolize
  • 9. N acetyltalosaminuuronic acid
  • 10. a | Schematic representation of a cross-section of the cell envelope of Sulfolobus solfataricus showing the cytoplasmic membrane, withmembrane-spanning tetraether lipids and an S-layer composed of two proteins — a surface-covering protein (red oval) and a membrane-anchoring protein (yellow oblong). b | Schematic representation of a cell envelope of an archaeon that stains positive with the Gram stainand that contains a pseudomurein layer in addition to the S-layer. The cytoplasmic membrane is composed of diether lipids.
  • 11. Some Hyperthermophiles Frequent habitats include volcanic vents and hot springs, as in the image to the leftPyrococcus abyssi 1µm Thermus aquaticus 1µm
  • 12. Deep Sea Extremophiles The deep-sea floor and hydrothermal vents involve the following conditions: low temperatures (2-3º C) – where only psychrophiles are present low nutrient levels – where only oligotrophs present high pressures – which increase at the rate of 1 atm for every 10 meters in depth (as we have learned, increased pressure leads to decreased enzyme- substrate binding) barotolerant microorganisms live at 1000-4000 metersA black smoker, a submarine barophilic microorganisms live at hot spring, which can reach depths greater than 4000 meters 518- 716°F (270-380°C)
  • 13. Extremophiles of Hydrothermal Vents Natural springs which vent warm or hot water on the sea floor near mid- ocean ridges. Associated with the spreading of 0.2µm 1µm the earth’sA cross-section of a bacterium A bacterial crust. Highisolated from a vent. Often community from a temperaturessuch bacteria are filled with deep-sea and pressuresviral particles which are hydrothermal ventabundant in hydrothermal near the Azores  vents
  • 14. Psychrophiles Some microorganisms thrive in temperatures well below the freezing point of water, such as in Some researchers believe that Antarcticapsychrophiles live in conditions mirroring those found on Mars
  • 15. Psychrophiles possess: -proteins rich in α-helices and polar groups which allow for greater flexibility -“antifreeze proteins” that maintain liquid intracellular conditions by lowering freezing points of other biomolecules -membranes that are more fluid, containing unsaturated cis-fatty acids which help to prevent freezing -active transport at lower temperatures
  • 16. Halophiles-Divided into mild (1-6%NaCl), moderate (6-15%NaCl), and extreme(15-30%NaCl)-Halophiles are mostly obligate aerobic archaeaHow do halophiles survive high salt concentrations?-by interacting more strongly with water such as using morenegatively charged amino acids in key structures-by making many small proteins inside the cell, and these, then,compete for the water-and by accumulating high levels of salt in the cell in order tooutweigh the salt outside
  • 17. Barophiles -Survive under levels of pressure that are otherwise lethal to other organisms -Usually found deep in the earth, in the deep sea, hydrothermal vents, etc1µm -scientists believe thatA sample of barophilic barophiles may bebacteria from the able to survive on theearth’s interior Moon and other places in space
  • 18. Xerophiles Extremophiles which live in water- scarce habitats, such as deserts Produce desert varnish as seen in the image to the left Desert varnish is a thin coating of Mn, Fe, and clay on the surface of desert rocks, formed by colonies of bacteria living on the rock surface for thousands of years
  • 19. SOME COMMON GENERA OF PROKARYOTE EXTREMOPHILES2um 1.8um 1um Thermotoga Aquifex Halobacterium0.6um 0.9um 0.9umMethanosarcina Thermoplasma Thermococcus1.3um 0.6um 0.7umThermoproteus Pyrodictium Ignicoccus
  • 20. Deinococcus radiodurans The Radiation Resistor -Possesses extreme resistance to up to 4 million rad of radiation, genotoxic chemicals (those that harm DNA), oxidative damage from peroxides/superoxides, high levels of ionizing and ultraviolet radiation, and dehydration -It has from four to ten DNA molecules compared to only one for most other bacteria 0.8µm-Contains many DNA repair enzymes, such as RecA, whichmatches the shattered pieces of DNA and splices them backtogether. During these repairs, cell-building activities are shut offand the broken DNA pieces are kept in place
  • 21. Chroococcidiopsis The Cosmopolitan Extremophile 1.5µm-A cyanobacteria which can survive in a variety of harshenvironments, such as hot springs, hypersaline habitats, hot,arid deserts throughout the world, and in the frigid RossDesert in Antarctica-Possesses a variety of enzymes which assist in suchadaptation
  • 22. Other Prokaryotic Extremophiles 1µm 1µmGallionella ferrugineaand Anaerobic bacteria(iron bacteria), from a cave Current efforts in microbial taxonomy are isolating more and more previously undiscovered extremophile species, in places where life was least expected
  • 23. EXTREME EUKARYOTES THERMOPHILES/ACIDOPHILES 2µm
  • 24. EXTREME EUKARYOTES PSYCHROPHILES 2µmSnow Algae (Chlamydomonas nivalis) A bloom of Chloromonas rubroleosa in Antarctica These algae have successfully adapted to their harsh environment through the development of a number of adaptive features which include pigments to protect against high light, polyols (sugar alcohols, e.g. glycerine), sugars and lipids (oils), mucilage sheaths, motile stages and spore
  • 25. EXTREME EUKARYOTES ENDOLITHS Quartzite from Johnson Canyon, California. Sample shows green bands of endolithic algae. Rock is 9.5 cm wide-Endoliths (also called hypoliths) are usuallyalgae, but can also be prokaryotic cyanobacteria,that exist within rocks and caves-Often are exposed to anoxic (no oxygen) andanhydric (no water) environments
  • 26. EXTREME EUKARYOTES PARASITES -Members of the Phylum Protozoa, which are regarded as the earliest eukaryotes to evolve, are mostly parasites -Parasitism is often a stressful relationship on both host and parasite, so they are considered extremophiles 20µm 15µmTrypanosoma gambiense, Balantidium coli, causescauses African sleeping dysentery-like symptomssickness
  • 27. EXTREME VIRUSES Viruses are currently being isolated from habitats where temperatures exceed 200°F Instead of the usual icosahedral or rod-shaped capsids that known viruses possess, researchers have 40nm found viruses with novelVirus-like particles propeller-like structuresisolated from the extremeenvironment ofYellowstone National Park These extreme viruses oftenhot springs live in hyperthermophile prokaryotes such as Sulfolobus
  • 28. CLASSIFICATION OF EXTREMOPHILES Phylogenetic Relationships Extremophiles are present among Bacteria, formthe majority of Archaea, and also a few among the Eukarya
  • 29. PHYLOGENETIC RELATIONSHIPS-Members of Domain Bacteria (such as Aquifex and Thermotoga) that are closer to the root of the “tree of life” tend to be hyperthermophilic extremophiles-The Domain Archaea contain a multitude of extremophilic species: Phylum Euryarchaeota-consists of methanogens and extreme halophiles Phylum Crenarchaeota-consists of thermoacidophiles, which are extremophiles that live in hot, sulfur-rich, and acidic solfatara springs Phylum Korarchaeota-new phylum of yet uncultured archaea near the root of the Archaea branch, all are hyperthermophiles-Most extremophilic members of the Domain Eukarya are red and green algae
  • 30. Chronology of Life
  • 31. The First Organisms?Early Earth was largely inhospitable: high CO 2/H2S/H2 etc, low oxygen, and high temperaturesLifeforms that could evolve in such an environment needed to adapt to these extreme conditionsH2 was present in abundance in the early atmosphere. Many hyperthermophiles and archaea are H2 oxidizersThus, it is widely held that extremophiles represent the earliest forms of life with non-extreme forms evolving after cyanobacteria had accumulated enough O2 in the atmosphereResults of rRNA and other molecular techniques have placed hyperthermophilic bacteria and archaea at the roots of the phylogenetic tree of life
  • 32. Evolutionary Theories Consortia- symbiotic relationships between microorganisms, allows more than one species to exist in extreme habitats because one species provides nutrients to the others and vice versa Genetic drift appears to have played a major role in how extremophiles evolved, with allele frequencies randomly changing in a microbial population. So alleles that conferred adaptation to harsh habitats increased in the population, giving rise to extremophile populations Geographic isolation may also be a significant factor in extremophile evolution. Microorganisms that became isolated in more extreme areas may have evolved biochemical and morphological characteristics which enhanced survival as opposed to their relatives in more temperate areas. This involves genetic drift as well
  • 33. Slower Evolution-Extremophiles, especially hyperthermophiles, possess slow “evolutionary clocks”-That is, they have not evolved much from their ancestors as compared to other organisms-Hence, hyperthermophiles today are similar to hyperthermophiles of over 3 billion years ago-Slower evolution may be the direct result of living in extreme habitats and little competition-By contrast, other extremophiles, such as extreme halophiles and psychrophiles, appear to have undergone faster modes of evolution since they live in more specialized habitats that are not representative of early earth conditions
  • 34. Mat Consortia Mat Consortia A mat consortia in Yellowstone-Microbial mats consist of an upper layer of photosyntheticbacteria, with a lower layer of nonphotosynthetic bacteria-These consortia may explain some of the evolution that hastaken place: extremophiles may have relied on otherextremophiles and non-extremophiles for nutrients and shelter-Hence, evolution could have been cooperative
  • 35. USES OF EXTREMOPHILESHYPERTHERMOPHILES (SOURCE) USESDNA polymerases DNA amplification by PCRAlkaline phosphatase DiagnosticsProteases and lipases Dairy productsLipases, pullulanases and proteases DetergentsProteases Baking and brewing and amino acid production from keratinAmylases, α-glucosidase, pullulanase and xylose/glucose isomerases Baking and brewing and amino acid production from keratinAlcohol dehydrogenase Chemical synthesisXylanases Paper bleachingLenthionin PharmaceuticalS-layer proteins and lipids Molecular sievesOil degrading microorganisms Surfactants for oil recoverySulfur oxidizing microorganisms Bioleaching, coal & waste gas desulfurizationHyperthermophilic consortia Waste treatment and methane production
  • 36. USES OF EXTREMOPHILESPSYCHROPHILES (SOURCE) USESAlkaline phosphatase Molecular biologyProteases, lipases, cellulases and amylases DetergentsLipases and proteases Cheese manufacture and dairy productionProteases Contact-lens cleaning solutions, meat tenderizingPolyunsaturated fatty acids Food additives, dietary supplementsVarious enzymes Modifying flavorsb-galactosidase Lactose hydrolysis in milk productsIce nucleating proteins Artificial snow, ice cream, other freezing applications in the food industryIce minus microorganisms Frost protectants for sensitive plantsVarious enzymes (e.g. dehydrogenases) BiotransformationsVarious enzymes (e.g. oxidases)Bioremediation, environmental biosensorsMethanogens Methane production
  • 37. USES OF EXTREMOPHILESHALOPHILES (SOURCE) USESBacteriorhodopsin Optical switches and photocurrent generators in bioelectronicsPolyhydroxyalkanoates Medical plasticsRheological polymers Oil recoveryEukaryotic homologues (e.g. myc oncogene product) Cancer detection, screening anti-tumor drugsLipids Liposomes for drug delivery and cosmetic packagingLipids Heating oilCompatible solutes Protein and cell protectants in variety of industrial uses, e.g. freezing, heatingVarious enzymes, e.g. nucleases, amylases, proteases Various industrial uses, e.g. flavoring agentsg-linoleic acid, b-carotene and cell extracts, e.g. Spirulina and Dunaliella Health foods, dietary supplements, food coloring and feedstockMicroorganisms Fermenting fish sauces and modifying food textures and flavorsMicroorganisms Waste transformation and degradation, e.g. hypersaline waste brines contaminated with a wide range of organicsMembranes Surfactants for pharmaceuticals
  • 38. USES OF EXTREMOPHILESALKALIPHILES (SOURCE) USESProteases, cellulases, xylanases, lipases and pullulanases DetergentsProteases Gelatin removal on X-ray filmElastases, keritinases Hide dehairingCyclodextrins Foodstuffs, chemicals and pharmaceuticalsXylanases and proteases Pulp bleachingPectinases Fine papers, waste treatment and degummingAlkaliphilic halophiles Oil recoveryVarious microorganisms AntibioticsACIDOPHILES (SOURCE) USESSulfur oxidizing microorganisms Recovery of metals and desulfurication of coalMicroorganisms Organic acids and solvents
  • 39. Taq Polymerase Isolated from the hyperthermophile Thermus aquaticus Much more heat stable Used as the DNA polymerase in the very useful Polymerase Chain Reaction (PCR) technique which amplifies DNA samples
  • 40. Alcohol Dehydrogenase -Alcohol dehydrogenase (ADH), is derived from a member of the archaea called Sulfolobus solfataricus -It works under some of natures harshest volcanic conditions: It can survive to 88°C (190ºF) - nearly boiling - and corrosive acid conditions (pH=3.5) approaching the sulfuric acid found in a car battery (pH=2) -ADH catalyzes the conversion of alcohols and has considerable potential for biotechnology applications due to its stability under these extreme conditions
  • 41. Bacteriorhodopsin -Bacteriorhodopsin is a trans-membrane protein found in the cellular membrane of Halobacterium salinarium, which functions as a light- driven proton pump -Can be used for electrical generation
  • 42. Bioremediation- Bioremediation is the branch of biotechnology that uses biological processes to overcome environmental problems- Bioremediation is often used to degrade xenobiotics introduced into the environment through human error or negligence - Part of the cleanup effort after the 1989 Exxon Valdez oil spill included microorganisms induced to grow via nitrogen enrichment of the contaminated soil
  • 43. Bioremediation
  • 44. Psychrophiles as Bioremediators- Bioremediation applications with cold- adapted enzymes are being considered for the degradation of diesel oil and polychlorinated biphenyls (PCBs)- Health effects that have been associated with exposure to PCBs include acne-like skin conditions in adults and neurobehavioral and immunological changes in children. PCBs are known to cause cancer in animals
  • 45. An End to Pollution?New and innovative methods are beingdeveloped that utilize extremophiles for theelimination of pollution resulting from oilslicks, toxic chemical spills, derelict mines,etc
  • 46. Life in Outer Space?-Scientists have decided on 3 requirements for life: water energy carbon-Astrobiology: field of biology dealing with the existence of life beyond earth-Astrobiologists are currently looking for life on Mars, Jupiter’s moon Europa, and Saturn’s moon Titan-Such life is believed to consist of extremophiles that can withstand the cold and pressure differences -Mudslide-like formations have been found on Mars (left). These appear to have been caused by water movements. Psychrophiles may exist there
  • 47. Life in Outer Space? -Europa is thought to have an ice crust shielding a 30-mile deep ocean. Reddish cracks (left) are visible in the ice and may be evidence of living populations -Titan is enveloped with a hazy gas (left) that is believed to contain some organic molecules, ie methane. This may provide sustenance for life on Titan’s surfaceImages courtesy of the Current Science & Technology Center
  • 48. Life in Outer Space? -Scientists have found that meteorites contain amino acids and simple sugars, very important building blocks. These may serve to spread life throughout the universeImage courtesy of the Current Science & Technology Center -A sample of stratospheric air had shown a myriad of bacterial diversity 41 km above the earth’s surface (Lloyd, Harris, & Narlikar, 2001) Indeed, we may not be alone
  • 49. A. The archaea are quite diverse, both in morphology and physiology 1. They may stain gram positive or gram negative 2. They may be spherical, rod-shaped, spiral, lobed, plate-shaped, irregularly shaped or pleomorphic 3. They may exist as single cells, aggregates or filaments 4. They may multiply by binary fission, budding, fragmentation, or other mechanisms 5. They may be aerobic, facultatively anaerobic, or strictly anaerobic 6. Nutritionally, they range from chemilithoautotrophs to organotrophs 7. Some are mesophiles, while others are hyperthermophiles that can grow above 100°C 8. They are often found in extreme aquatic and terrestrial habitats; recently, archaea have been found in cold environments and may constitute up to 34% of the procaryotic biomass in Antarctic surface waters; a few are symbionts in animal digestive systems
  • 50. Archaeal cell walls 1. Archaea can stain either gram positive or gram negative, but their cell wall structure differs significantly from that of bacteria a. Many archaea that stain gram positive have a cell wall made of a single homogeneous layer b. The archaea that stain gram negative lack the outer membrane and complex peptidoglycan network associated with gram-negative bacteria 2. Archaeal cell wall chemistry is different from that of bacteria a. Lacks muramic acid and D-amino acids and therefore is resistant to lysozyme and b-lactam antibiotics b. Some have pseudomurein, a peptidoglycan-like polymer that has L-amino acids in its cross-links and different monosaccharide subunits and linkage c. Others have different polysaccharides 3. The archaea that stain gram negative have a layer of protein or glycoprotein outside their plasma membrane
  • 51. Archaeal lipids and membranes 1. Lipids have branched hydrocarbons attached to glycerol by ether links rather than straight-chain fatty acids attached to glycerol by ester links as seen in Bacteria and Eucarya 2. Other, more complex tetraether structures are also found 3. Membranes contain polar lipids such as phospholipids, sulfolipids, and glycolipids and also contain nonpolar lipids (7-30%), which are usually derivatives of squalene 4. Membranes of extreme thermophiles are almost completely tetraether monolayers
  • 52. F. • Archaeal Taxonomy-the new edition of Bergey’s Manual will divide the archaea into two phyla: Euryarchaeota and Crenarchaeota• Phylum Crenarchaeota A. Many are extremely thermophilic, acidophilic, and sulfur- dependent 1. Sulfur may be used as an electron acceptor in anaerobic respiration, or as an electron source by lithotrophs 2. Almost all are strict anaerobes 3. They grow in geothermally heated water or soils (solfatara) that contain elemental sulfur (sulfur-rich hot springs, waters surrounding submarine volcanic activity); some (e.g., Pyrodictum spp.) can grow quite well above the boiling point of water (optimum @ 105oC) 4. Some are organotrophic; others are lithotrophic 5. There are 69 genera; two of the better-studied genera are Sulfolobus and Thermoproteus
  • 53. A. Sulfolobus 1. Stain gram negative; are aerobic, irregularly lobed, spherical bacteria 2. Thermoacidophiles 3. Cell walls lack peptidoglycan but contain lipoproteins and carbohydrates 4. Oxidize sulfur to sulfuric acid; oxygen is the normal electron acceptor, but ferric iron can also be used 5. Sugars and amino acids may serve as carbon and energy sources
  • 54. A. Thermoproteus 1. Long, thin, bent or branched rods 2. Cell wall is composed of glycoprotein 3. Strict anaerobes 4. They have temperature optima from 70-97°C and pH optima from 2.5 to 6.5 5. They grow in hot springs and other hot aquatic habitats that contain elemental sulfur 6. They carry out anaerobic respiration using organic molecules as electron donors and elemental sulfur as the electron acceptor; they can also grow lithotrophically using H2 and S0 as electron donors and CO or CO2 as the sole carbon source
  • 55. • Phylum Euryarchaeota A. The Methanogens 1. Strict anaerobes that obtain energy by converting CO2, H2, formate, methanol, acetate, and other compounds to either methane or to methane and CO2; there are at least five orders, which differ greatly in shape, 16S rRNA sequence, cell wall chemistry and structure, membrane lipids, and other features 2. Methanogens belonging to the order Methanopyrales have been suggested to be among the earliest organisms to evolve on Earth 3. Methanogenesis is an unusual metabolic process and methanogens contain several unique cofactors 4. They thrive in anaerobic environments rich in organic matter, such as animal rumens and intestinal tracts, freshwater and marine sediments, swamps, marshes, hot springs, anaerobic sludge digesters, and even within anaerobic protozoa 5. They are of great potential importance because methane is a clean-burning fuel and an excellent energy source 6. They may be an ecological problem, however, because methane is a greenhouse gas that could contribute to global warming and also because methanogens can oxidize iron, which contributes significantly to the corrosion of iron pipes
  • 56. A. The Halobacteria 1. A group of extremely halophilic organisms divided into 15 genera a. They are aerobic chemoheterotrophs with respiratory metabolism; they require complex nutrients b. Motile or nonmotile by lophotrichous flagella 2. They require at least 1.5 M NaCl and have growth optima near 3-4 M NaCl (if the NaCl concentration drops below 1.5 M the cell walls disintegrate; because of this they are found in high-salinity habitats and can cause spoilage of salted foods 3. Halobacterium salinarum uses four different light- utilizing rhodopsin molecules a. Bacteriorhodopsin uses light energy to drive outward proton transport for ATP synthesis; thus they carry out a type of photosynthesis that does not involve chlorophyll b. Halorhodopsin uses light energy to transport chloride ions into the cell to maintain a 4-5 M intracellular KCl concentration c. Two other rhodopsins act as photoreceptors that control flagellar activity to position the bacterium in the water column at a location of high light intensity, but one in which the UV light is not sufficiently intense to be lethal
  • 57. A. The Thermoplasms0. Thermoacidic organisms that lack cell walls; only two genera are know: Thermoplasma and Picrophilus 1. Thermoplasma a. Frequently found in coal mine refuse, in which chemolithotrophic bacteria oxidize iron pyrite to sulfuric acid and thereby produce a hot acidic environment b. Optimum temperature for growth of 55-59°C and an optimal PH of 1 to 2 c. Cell membrane is strengthened by large quantities of diglycerol tetraethers, lipopolysaccharides, and glycoproteins d. Histonelike proteins stabilize their DNA; DNA- protein complex forms particles resembling eucaryotic nucleosomes e. At 59oC Thermoplasma takes the form of an irregular filament; the cells may be flagellated and motile
  • 58. 1. Picrophilus a. Isolated from hot solfateric fields b. Has an S-layer outside the plasma membrane c. Irregularly shaped cocci with large cytoplasmic cavities that are not membrane bounded d. Aerobic and grows between 47°C and 65°C with an optimum of 60°C e. It grows only below pH 3.5, has an optimum of pH 0.7 and will even grow at or near pH 0
  • 59. A. Extremely thermophilic S0 metabolizers0. Strictly anaerobic, reduce sulfur to sulfide 1. Are motile by means of flagella 2. Have optimum growth temperatures around 88-100°C B. Sulfate-reducing archaea0. Gram-negative, irregular coccoid cells with walls of glycoprotein subunits 1. Use a variety of electron donors (hydrogen, lactate, glucose) and reduce sulfite, sulfate, or thiosulfate to sulfide 2. Are extremely thermophilic (optimum around 83°C); they are usually found near marine hydrothermal vents 3. Contain two methanogen coenzymes
  • 60. CONCLUSIONS-Extremophiles are a very important and integral part of the earth’s biodiversityThey: - reveal much about the earth’s history and origins of life - possess amazing capabilities to survive in the extremes - are proving to be beneficial to both humans and the environment -may exist beyond earth