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![Property Archaea Bacteria Eukarya
Cell Membrane Ether-linked lipids,
pseudopeptidoglycan
Ester-linked lipids,
peptidoglycan
Ester-linked lipids, various
structures
Gene Structure
Circular chromosomes,
similar translation and
transcription to Eukarya
Circular chromosomes,
unique translation and
transcription
Multiple, linear
chromosomes, similar
translation and
transcription to Archaea
Internal Cell Structure No membrane-bound
organelles or nucleus
No membrane-bound
organelles or nucleus
Membrane-bound
organelles and nucleus
Metabolism[45]
Various, with
methanogenesis
unique to Archaea
Various, including
photosynthesis, aerobic
and anaerobic respiration,
fermentation, and
autotrophy
Photosynthesis and
cellular respiration
Reproduction Asexual reproduction,
horizontal gene transfer
Asexual reproduction,
horizontal gene transfer
Sexual and asexual
reproduction
Comparison to other domains](https://image.slidesharecdn.com/ggarchea-141120054645-conversion-gate01/85/archea-7-320.jpg)
![ Physiology
Aerobic, facultative and strictly anaerobic
Range from chemolithotrophs to organotrophs
Mesophilic & hyperthermophiles
Found in extreme environments
Few are symbionts in animal digestive system
eg- the marine archaean Cenarchaeum symbiosum lives
within (is an endosymbiont of) the sponge
Axinella mexicana.[180]
CCoonnttdd……](https://image.slidesharecdn.com/ggarchea-141120054645-conversion-gate01/85/archea-10-320.jpg)
![ Genomes are significantly smaller than bacteria.
E. coli – 2.5 x 109 Daltons
T. acidophilum – 0.8 x 109 Daltons
Methanosarcina acetivorans,[116] the largest known
archaeal genome.
Nanoarchaeum equitans, the smallest archaeal genome
known;
plasmids are also found
Archaea usually have a single circular chromosome](https://image.slidesharecdn.com/ggarchea-141120054645-conversion-gate01/85/archea-21-320.jpg)
More Related Content
archea
- 1. ARCHAEA BACTERIA GGEEOOGGEEOORRGGEE KKaannnnuurr uunniivveerrssiittyy
- 2. Early Origins Classification What They Look Like? What They Eat? Where They’re Found? How They’re Different?
- 4. Phylogenetic tree oflife..
- 5. New branch oflife.... In 1970s carl woese proposed -3 domain classification Based on sequencing of 16s r RNA The organism he revealed-the achea.. Classifying Archaea remains difficult, majority of these organisms have never been studied in the laboratory and have only been detected by analysis of their nucleic acids in environmental samples.- ( metagenomics) CCaarrll wwooeessee
- 6. Archaea are morewounderful than you know...! TThheerrmmooccooccccuuss ggaammmmaattoolleerraannss –– aa ffllaaggeellllaattee aarrcchhaaeeoonn tthhaatt tthhrriivveess iinn hhoott,, ooxxyyggeenn--ssttaarrvveedd wwaatteerrss.. NNoottee tthhee ttuufftt ooff ffllaaggeellllaa.. TThhiiss mmiiccrroobbee lliivveess iinn wwaatteerr hhootttteerr tthhaann aabboouutt 116600FF
- 7. Property Archaea BacteriaEukarya Cell Membrane Ether-linked lipids, pseudopeptidoglycan Ester-linked lipids, peptidoglycan Ester-linked lipids, various structures Gene Structure Circular chromosomes, similar translation and transcription to Eukarya Circular chromosomes, unique translation and transcription Multiple, linear chromosomes, similar translation and transcription to Archaea Internal Cell Structure No membrane-bound organelles or nucleus No membrane-bound organelles or nucleus Membrane-bound organelles and nucleus Metabolism[45] Various, with methanogenesis unique to Archaea Various, including photosynthesis, aerobic and anaerobic respiration, fermentation, and autotrophy Photosynthesis and cellular respiration Reproduction Asexual reproduction, horizontal gene transfer Asexual reproduction, horizontal gene transfer Sexual and asexual reproduction Comparison to other domains
- 8. Introduction to the AMrocrhpahoeloagy Stain either Gram +ve or Gram –ve Shapes – Spherical, rod, spiral, lobed, irregularly shaped or pleomorphic Single cells or filaments or aggregates, diameter from 0.1 to over 15 μm Multiplication – binary fission, budding, fragmentation or other unknown mechanisms CCoonnttdd……
- 9. A postage-ssttaammpp lliikkeesshheeeett ooff tthhee ssqquuaarree cceellllss ooff HHaallqquuaaddrraattuumm wwaallssbbyyii..
- 10. Physiology Aerobic,facultative and strictly anaerobic Range from chemolithotrophs to organotrophs Mesophilic & hyperthermophiles Found in extreme environments Few are symbionts in animal digestive system eg- the marine archaean Cenarchaeum symbiosum lives within (is an endosymbiont of) the sponge Axinella mexicana.[180] CCoonnttdd……
- 11. Archaeal cell envelopes One of he distinctive feature of the archaea is the nature of envelope S-layer is the major component of the cellwall Some archaea lacks cellwall but have a glyocalyx lying out side the cell membrane Capsules and slime layers are rare among archaea
- 12.
- 13. Archael cellwalllacks peptidoglycan and exhibit considerable variety in terms of their chemical make up The most common type of archaeal cell wall is an S-layer composed of either protein or glycoprotein the layer may be as thick as 20 to 40 nm. eg; methanococcus, halobacterium Other archaea have additional layers of material outside the S-layer methanospirillum has a protein sheath external to the s-layer methanosarcina has a layer of chondroitin- like material, this material is called methanochondroitin
- 14. In somearchaea S-layer is the outer most layer and seperated from the plasma membrane by pseudomurein pseudomurein is a peptidogycan-like molecule. differs from pepidoglycan in that it has N-acetyltalosaminuronic acid instead of N-acetylmuramic acid ,and beta (1 3)glycosidic linkage insted of beta (1 4) glycosidic linkage. eg- Methanobacterium, Methanothermus and Methanopyrus The last type of archael cellwall does not include an s-layer .these archaea have a wall with a single, homogenous layer resembling in gram-positive bacteria
- 16. pseudomurein Substitutesfor N-Acetylmuramic acid(NAM) of peptidoglycan
- 17. Archaeal Lipids &Membranes
- 18. Archaeal plasma membranes Archaeal membranes are composed primerly of lipids that differ from bacterial and eukaryotic in two ways. 1. They contain hydrocarbons derived from isoprene units(five carbon, branched) 2. Hydrocarbons attached to glycerol by ether linkage rather than ester links
- 19. Archaeal phospholipidsdiffer from those found in Bacteria and Eukarya in two ways. First, they have branched phytanyl sidechains instead of linear ones. Second, an ether bond instead of an ester bond connects the lipid to the glycerol. CCoonnttdd……
- 20. Genetics & MolecularBiology
- 21. Genomes aresignificantly smaller than bacteria. E. coli – 2.5 x 109 Daltons T. acidophilum – 0.8 x 109 Daltons Methanosarcina acetivorans,[116] the largest known archaeal genome. Nanoarchaeum equitans, the smallest archaeal genome known; plasmids are also found Archaea usually have a single circular chromosome
- 22. Transcription and translationin archaea resemble these processes in eukaryotes more than in bacteria Archaea have a single type of RNA Polymerase and similar to eukaryotes archaeal genes lack introns Hyperthermophiles posses reverse DNA gyrase
- 23. GGrraanndd PPrriissmmaattiicc SSpprriinnggaatt YYeelllloowwssttoonnee NNaattiioonnaall PPaarrkk,, hhoommee ooff lloottss ooff aarrcchhaaeebbaacctteerriiaa
- 24.
- 25. Archaea exhibita great variety of chemical reactions in their metabolism and use many sources of energy. Some archaea obtain energy from inorganic compounds such as sulfur or ammonia (they are lithotrophs). These include nitrifiers, methanogens andanaerobic methane oxidisers. Other groups of archaea use sunlight as a source of energy (they are phototrophs). However, oxygen– generating photosynthesis does not occur in any of these organisms.
- 26. CCoonnttdd…… archaeause a modified form of glycolysis (the Entner–Doudoroff pathway) and either a complete or partial citric acid cycle Methanogenesis occcurs in the phylum Euryarchaeota These reactions are common in gut-dwelling archaea archaea use CO2 in the atmosphere as a source of carbon, in a process called carbon fixation (they are autotrophs) Archaeal energy sources are extremely diverse, and range from the oxidation of ammonia by the Nitrosopumilales to the oxidation of hydrogen sulfide or elemental sulfur by species of Sulfolobus, using either oxygen or metal ions as electron acceptors. Phototrophic archaea use light to produce chemical energy in the form of ATP
- 27. Autotrophy is widespreadamong methanogens & extreme thermophiles Thermoproteus & Sulfolobus – fix CO2 by reductive TCA cycle Methanogens & extreme thermophiles –fix CO2 by reductive acetyl coA p/w Acetyl-CoA (Ljungdahl-Wood) pathway: A autotrophic CO2 fixing pathway widespread in strict anerobes (e.g. methanogens, homoacetogens & sulfatereducing bacteria). Some methanogens can fix atmospheric nitrogen Some stores glycogen has a storage form CCoonnttdd……
- 28. Nutritional type Sourceof energy Source of carbon Examples Phototrophs Sunlight Organic compounds Halobacteria Lithotrophs Inorganic compounds Organic compounds or carbon fixation Ferroglobus, Methanobacteria or Pyrolobus Organotrophs Organic compounds Organic compounds or carbon fixation Pyrococcus, Sulfolobus or Methanosarcinales Nutritio nal type s in aarrcchhaaeeaall mmeettaabboo lliissmm
- 29.
- 30. Members ofthe domain Archaea are phylogenetically divided into three kingdoms Euryarchaeotoa Crenarchaeota Korarchaeota • Phylogeny of domain Archaea based on comparision of the 16S rRNAsequences. Greek Archaios = ancient, primitive Greek Eurus = wide(wide distribution); Greek Crene = spring, fount (primary habitat). Korarchiota = young man
- 32. RReecceennttllyy ddeetteecctteedd ssppeecciieessooff aarrcchhaaeeaa.. AArrcchhaaeeaall RRiicchhmmoonndd MMiinnee aacciiddoopphhiilliicc ((AARRMMAANN)),, wwhhiicchh wweerree ddiissccoovveerreedd iinn 22000066
- 33. Phylum Crenarchaeota Mostare extremely thermophilic & many are acidophiles and S dependent S – as electron acceptor or electron source by lithotrophs Almost all are strict anaerobes & grow in geothermally heated water / soils that contain elemental sulfur CCoonnttdd……
- 34. Divided intoone class – Thermoprotrei & three orders : Thermoproteales Sulfolobales Desulfurococcales Contain 69 genera – two of the better studied genera are Thermoproteus & Sulfolobus CCoonnttdd……
- 35. Sulfolobus Gram–ve, aerobic, irregularly lobed spherical archaeons Optimum temp.– 70 to 80 0C & optimum pH 2 - 3 hence also referred to as thermoacidophiles Cell wall – lipoprotein & CH, lacks peptidoglycan Grow lithotrophically on S granules in hot S springs oxidizing S to Sulfuric acid Oxygen Is the normal electron acceptor, Fe+3 may be used CCoonnttdd……
- 36. Sugars &amino acids (glutamate) also serve as C & energy sources CCoonnttdd……
- 37. Thermoproteus Gram–ve, strictly anaerobic, hyperthermophilic long thin rod, can be bent or branched Cell wall consists of glycoprotein Grows at temp. from 70 - 97 0C & pH 2.5 – 6.5 Found in hot springs & other hot aquatic habitats rich in sulfur Can grow organotrophically & oxidize glucose, amino acids, alcohols & organic acids with S CCoonnttdd……
- 38. Grows chemolithtrophicallyusing Hydrogen & S0 CO & CO2 can serve as the sole C source An aquatic spring in Japan with Thermoproteus growth Thermoproteus CCoonnttdd……
- 39. Phylum Euryarchaeota Very diverse with 7 classes viz. Methanococcus, Methanobacteria, Halobacteria, Thermoplasmata, Thermococci, Archaeglobi & Methanopyri Consists of 9 orders & 15 families Includes methanogens, extreme halophiles, sulphate reducers & many extreme thermophiles with S dependent metabolism CCoonnttdd……
- 40. The Methanogens Methanogenic bacteria are extremely oxygen sensitive. Methanogens require anaerobic conditions . They are found in the digestive systems of herbivores, marshes or lake bottoms, all sorts of mud sediments and in man made anaerobic digestors in sewage treatment plants. They can be classified as Chemolithotrophic methanogens and Methylotrophic methanogens. Responsible for methanogenesis
- 41. Methanogenesis isthe biological production of CH4 from either CO2 plus H2 or from methylated organic compounds. A variety of unique coenzymes are involved in methanogenesis chemolithotrophic methanogens that grow with CO2 plus H2 according to the equation:- CO2 + 4H2 CH4 + 2H2O Methylotrophic methanogens that grow with methyl group containing substrates for eg. Methanol, methylamines, acetate The reaction for acetate is: CH3COOH CH4 + CH2 5 orders (Methanobacteriales, Methanococcales, Methanomicrobiales, Methanosarcinales & Methanopyrales) & 26 genera
- 42. Methane synthesis fromCO2 by Methanobacterium thermoautotrophicum CCoonnttdd……
- 43. Methane formation fromCO2 and H2 by Barker’s scheme. The first carrier molecule is Methanofuran. In a reaction that requires CO2 and reducing equivalents it is converted to formylmethanofuran with the formyl group residing at the aminomethyl group of the furan ring. Transfer of the C1 moiety to tetrahydromethanopterin and reduction of the formyl to methyl group follows. It is finally transferred to the Coenzyme M and is reduced to CH3 by the enzyme methyl co enzyme M methylreductase
- 44. Diversity of Methanogens Demonstrate diversity of cell wall chemistries Pseudomurein (e.g., Methanobacterium) Methanochondroitin (e.g., Methanosarcina) Protein or glycoprotein (e.g., Methanocaldococcus) S-layers (e.g., Methanospirillum)
- 47. Some liveautotrophically – acetyl coA from two molecules of CO2 & then converting acetyl coA to pyruvate & other products Found in anaerobic environment rich in organic matter Rumen & intestine of animals, fresh water & marine sediments, swamps & marshes, hot springs, anaerobic sludge digesters & anaerobic protozoa Ecological significance Cow belches 200 – 400 ltrs CH4/day Source of energy for sewage treatment plants CCoonnttdd……
- 48. Yellowstone National Park Ecological hazards Methane gas – Greenhouse gas Can oxidize Fe0 May contribute to corrosion of buried or submerged iron pipes M. thermoautotrophicum CCoonnttdd……
- 49. The Halobacteria Class Halobacteria – 15 genera in one family, the Halobacteriaceae Aerobic chemoheterotrophs with respiratory metabolism Non motile or motile by lophotrichous flagella Absolutely dependent on high NaCl conc. At least 1.5 M NaCl, growth optimum at 3 – 4 M Cell wall disintegrates below 1.5 M conc. Grow only in high salinity habitats Cause spoilage of salted fish CCoonnttdd……
- 50. E.g. Halobacterium salinarium Unusual type of photosynthesis On exposure to sunlight – purple membrane – bacteriorhodopsin Four types of rhodopsins Bacteriorhodopsin – proton transport for ATP synthesis Halorhodopsin – uses light energy to transport chloride ions into the cell & maintains KCl conc. Remaining two – photoreceptors, one for red light & one for blue CCoonnttdd……
- 51. Purple lake inAustralia H. salinarium CCoonnttdd……
- 52. The Thermoplasms archaea lack cell wall Class Thermoplasmata Two genera, Thermoplasma & Pichrophilus Thermoplasma Grows in refuse piles of coal mines Temperatures from 55 – 590C & pH 1-2 Plasma membrane is strengthened by large quantities of diglycerol, tetraethers, lipopolysaccharides & glycolipids DNA stabilized by nucleosomes CCoonnttdd……
- 53. At 590C -irregularly shaped & at lower temperatures – spherical May be motile by flagella CCoonnttdd……
- 54. Picrophilus Lackscell wall , has S layer outside PM Aerobic, irregularly shaped cocci, 1 – 1.5 μm in diameter Temp. range 47 – 650C, optimum temp. 600C pH below 3.5, optimum pH 0.7 Can grow at pH 0 CCoonnttdd……
- 55. Extremely Thermophilic S0 Metabolizers Class Thermococci, order Thermococcales Strictly anaerobic Reduce sulfur to sulfide Motile by flagella Optimum growth temp. 88 –1000C Two genera, Thermococcus & Pyrococcus CCoonnttdd……
- 56. Sulfate Reducing Archaea Class Archaeglobi, order Archaeoglobales Gram –ve, irregular coccoid cells Cell wall – glycoprotein subunits Electron sources – hydrogen, lactate & glucose, reduce sulfate, sulfite or thiosulfate to sulfide S is not used as electron acceptor Extremely thermophilic, optimum temp. around 830C, occur in hydrothermal vents CCoonnttdd……
- 57.
- 58. Methanogens areused for the production of methane which is a rich source of energy (bio gas) Methanogenic archaea are a vital part of sewage treatment Halophilic archaea are used to prescreen antitumor drugs active on eukaryotic proteins Thermophilic archaea are used in PCR thermostable DNA polymerases, such as the Pfu DNApolymerase from Pyrococcus furiosus, amylases,galactosidases and pullulanases in other species of Pyrococcus that function at over 100 °C (212 °F) allow food processing at high temperatures, such as the production of lactose milk and whey In mineral processing, acidophilic archaea display promise for the extraction of metals from ores, including gold, cobalt and copper.
- 59. References Prescott,Lansing M.; Harley, John P. and Klein, Donald A.,2003. Microbiology, 5th edition. McGraw – Hill www.euarch.blogspot.com www.filebox.vt.edu www.nature.com/ntmicro/journal/v5/n4 www.fib_tab/nrmicro1619_F3.html www.microbewiki.kenyon.edu/
- 60.