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===Higher order taxa===
===Higher order taxa===


Cellular organisms;Archaea; Euryarchaeota; Thermoplasmata; Thermoplasmatales; Thermoplasmataceae; Thermoplasma ''acidophilum''
cellular organisms; Archaea; Euryarchaeota; Thermoplasmata; Thermoplasmatales; Thermoplasmataceae; Thermoplasma; ''Thermoplasma acidophilum''


===Genus===  
===Genus===  
Thermoplasma ''acidophilum''
''Thermoplasma acidophilum''  




Line 18: Line 19:


==Description and significance==
==Description and significance==
[[Image:Thermoplasma.jpg|thumb|Thermoplasma acidophilum. Linda Stannard, UCT/Photo Science Library.|200px|right]]  
[[Image:Thermoplasma.jpg|thumb|''Thermoplasma acidophilum''. Linda Stannard, UCT/Photo Science Library.|150px|right]]  
''Thermoplasma acidophilum'' is a thermophilic heterotrophic prokaryote and is "among the most acidophilic organism known.”(2) They grow at 55-60°C and favor a range pH of 0.5-4; It was found and first isolated from self-heating coal refuse piles and solfatara fields. (3)


Scientists have long been fascinated by the ability of this microorganism to grow at high temperatures and low pH, they are specially interested in the protein these organism have because common proteins are denatured under acidic and hot environments without the structural protection of a conventional cell wall.


“Thermoplasma ''acidophilum'' is a thermophilic heterotrophic prokaryote growing at 55-60°C and pH 0.5-4, It is among the most acidophilic organisms known.” It is found and first isolated from self-heating coal refuse piles and solfatara fields.
''Thermoplasma acidophilum''’s genome contain special gene that allow this organism to survive in an environment similar in temperature and acidity to hot vinegar. (4)
 
By determining and studying the genome sequence of this organism, we will develop a better understanding of protein folding and degradation; it will also present a more complete representation of the proteins involved in different system of our body. (3)
“Microbial physiologists and structural biologists have long been fascinated by the ability of this microorganism to grow at high temperatures and low pH without the structural protection of a conventional cell wall”, “our interest in protein folding and degradation led us to seek a more complete representation of the proteins involved in these pathways by determining the genome sequence of this organism.”


==Genome structure==
==Genome structure==
Thermoplasma ''acidophilum''’s genome contain special gene that allow this organism to survive in an environment similar in temperature and acidity to hot vinegar.


The genome is a single circular chromosome and was sequenced using a new strategy called "shotgun sequencing".It is one of the smallest microbial genomes ever sequenced.
The genome of ''Thermoplasma'' is a single circular chromosome (1.56Mbp, containing 1509 ORFs)(4) and it is one of the smallest microbial genomes ever sequenced. (3)


[[Image:Phylogenetic tree.gif|alt Phylogenetic tree of 16S rRNA modified from Schleper et al.,
[[Image:Phylogenetic tree.gif|alt Phylogenetic tree of 16S rRNA modified from Schleper et al.,
J. Bacteriol., 177: 7050-7059 (1995)]]
J. Bacteriol., 177: 7050-7059 (1995)]]


“The genome of the organism consists of a single circular chromosome of 1.56 Mbp, containing 1509 ORFs. These identify Thermoplasma as a typical euryarchaeon with a substantial complement of bacterial-related genes. However, massive lateral gene transfer appears to have occurred between Thermoplasma and Sulfolobus ''solfataricus'', a phylogenetically distant crenarchaeon inhabiting the same environment.”
Surprisingly, the characteristics of ''Thermoplasma acidophilum''’s  small genome identify these organisms as a“typical euryarchaeon with a substantial complement of bacterial-related genes.” However,massive lateral gene transfer appears to have occurred between ''Thermoplasma'' and ''Sulfolobus solfataricus'', "a phylogenetically distant crenarchaeon inhabiting the same environment." (2)


==Cell structure and metabolism==
==Cell structure and metabolism==
Species of the genus Thermoplasma lack rigid cell wall, but are only delimited by a plasma membrane, it is “devoid of protective outer shells (S-layer, cell wall), yet maintains a near-neutral cytosolic pH.”


Species of the genus ''Thermoplasma'' lack a rigid cell wall, but still have a plasma membrane, it is “devoid of protective outer shells (S-layer, cell wall), yet maintains a near-neutral cytosolic pH.” (4)
The lipid composition of ''T. acidophilum'' has been the subject of several investigations. This work has revealed the presence of “large polar lipids, often glycosylated with glucose, mannose and glucose, phosphorylated, or both, forming phosphoglycolipids” (5). These unusual lipid compositions allow ''T.acidophilum'' to survive under the harsh conditions of temperature and pH“restricting proton flow across the membrane more efficiently than non-branched lipids (6)” As the structure of branched lipid blocks the transport pathway of proton, neutral pH can be maintained within the cell membrane.


“The lipid composition of T. ''acidophilum'' has been the subject of several investigations. This work has revealed the presence of large polar lipids, often glycosylated with glucose, mannose and gulose, phosphorylated, or both, forming phosphoglycolipids (Shimada et al, 2002). These unusual lipid compositions help the organism survive under these otherwise harsh conditions of temperature and pH by restructing proton flow across the membrane more efficiently than non-branched lipids (Baba et al, 2001)”


The Entner-Doudoroff pathway can only occur in prokaryotes like ''Thermoplasma''. This pathway is a series of reactions that “catabolize glucose to pyruvate using a different set of enzymes other than those used in either glycolysis or the pentose phosphate pathway. A distinct feature of Entner-Doudoroff pathway is that it uses 6-phosphogluconate dehydrase and 2-keto-3-deoxyglucosephophate aldolase to create pyruvates from glucose." (14)


T. ''acidophilum'' is able to gain energy in several ways, either anaerobically by sulphur respiration or as a scavenger in extreme environment.
In ''Thermoplasma'', glucose degradation is done by a “non-phosphorylated variant of the Entner–Doudoroff pathway, in which the first step is catalyzed by glucose dehydrogenase.” Acetyl-CoA produced from this pathway enters the TCA cycle. The presence of glycolysis/gluconeogenesis has not yet been confirmed due to the absence of phosphofructokinase and fructose in this organism. (7)
In Thermoplasma, “glucose degradation proceeds by a non-phosphorylated variant of the Entner–Doudoroff pathway, in which the first step is catalysed by glucose dehydrogenase. The acetyl-CoA produced in this pathway enters the oxidative tricarboxylic acid (TCA) cycle.” (the presence of enzyme require for this pathway had already been experimentally confirmed), the presence of glycolysis/gluconeogenesis has not yet been confirmed due to the absence of phosphofructokinase and fructose in this organism.


==Ecology==
==Ecology==
Thermoplasma ''acidophilum'' plays an important role in the ecosystem, they act as scavenger of those extreme environment. “It has adapted to scavenging nutrients from the decomposition of organisms killed by the extreme acidity and requires yeast, bacterial or meat extract when grown in culture.”
''Thermoplasma acidophilum'' plays an important role in the ecosystem. They act as scavengers in those extreme environment. “It has adapted to scavenging nutrients from the decomposition of organisms killed by the extreme acidity and requires yeast, bacterial or meat extract when grown in culture.” (3)




The study and research on Thermoplasma ''acidophilum'' indicate that an aqueous extract of coal refuse will serve as a nutrient source this the first step leading to the discovery of the materials in coal refuse which support its growth. Indeed, the coal refuse material provides nutrients for the growth of a wide variety of microorganisms and could be a source of new growth factors.
The study of ''Thermoplasma acidophilum'' indicate that an aqueous extract of coal refuse will serve as a nutrient source. This is the first step leading to the discovery of the materials in coal refuse which support its growth. Indeed, the coal refuse material provides nutrients for the growth of a wide variety of microorganisms and could be a source of new growth factors. (8)


==Pathology==
==Pathology==
None of the archaea organism include Thermoplasma ''acidophilum'' had known to cause pathogen to human being.
None of the archaea organisms, including ''Thermoplasma acidophilum'', are known to cause disease in human beings.


==Application to Biotechnology==
==Application to Biotechnology==
“The 20S proteasome from T. ''acidophilum'' caught scientist attention recently because it's proteolytic mechanism is common between the archaebacterial and the eukaryotic forms of the enzyme which is clinically relavent.” (Wlodawer, 1995)
Studies of the 20S proteasome from ''T.acidophilum'' has revealed that its proteolytic mechanism is similar to eukaryotic forms of the enzyme that are clinically relevant. (9)


In higher eukaryotes, proteasome is involved in housekeeping and protein level regulation. Further understand of chemical mechanism of this enzyme can help us to understand disease cause by the mutation of protesomes such as cystic fibrosis, Angelman's syndrome, Parkinson's disease and Liddle syndrome (Vu et al, 2000; Schwartz et al, 1999).
In higher eukaryotes, the proteasome is involved in housekeeping and protein level regulation; Further understanding of the chemical mechanism of this enzyme can help us to understand diseases caused by the mutation of protesomes such as cystic fibrosis, Angelman's syndrome, Parkinson's disease, Liddle syndrome even cancer(10).


“Dysregulation of this enzymatic system may also play a role in tumor progression, drug resistance, and altered immune surveillance, making the proteasome an appropriate and novel therapeutic target in cancer.”
"Deregulation of this enzymatic system may also play a role in tumor progression, drug resistance, and altered immune surveillance, making the proteasome an appropriate and novel therapeutic target in cancer."(1) The proteasome is also involved in apoptosis, a process to safely dispose of cell corpses and fragment. Apoptosis is a main type of programmed cell death, it plays a critical role in preventing cancer; if a cell fails to undergo apoptosis, it can continue dividing and develop into tumor. (16)


==Current Research==
==Current Research==


1) “Large chunks of DNA which have been borrowed from other species of microbe and incorporated into the chromosome of ''acidophilum''. The genes are believed to come from microbes and bacteria that share the same environmental niches, like the soil near hydrothermal sites.”
Origin of eukaryotic cell nuclei by symbiosis of archaea in bacteria supported by the newly clarified origin of functional genes of ''Thermoplasma acidophilum'' and 21 other unicellular organisms. This striking research suggests eukaryotic cell nuclei also undergo a process call endosymbiosis like mitochondria and chloroplast long time ago. Scientist did this by counting count the numbers of ORF (Orthologous ORFs were produced by speciation from a common ancestor, and have the highest similarity to each other); it was possible to detect the correct orthologous ORFs and to match up the origins of the functional categories in eukaryotic cells. Result find out there are lots of similarities between these two.(18)


2) Ubiquitin found in the archaebacterium Thermoplasma ''acidophilum'' strongly suggests that ATP-ubiquitin-dependent proteolysis is a cellular function that developed early in evolution.


3) Tremendous amount of research had been made on 20S proteasome of T.''acidophilum'', because this enzyme is common in higher eukaryotic organism and can play an important role on medical research.


==References==
The role of hydrophobic interactions in maintaining high temperature stability is investigated by citrate synthase of ''T.acidophilum'' as a thermostable model system. Scientists find that increasing or decreasing the hydrophobicity could further increase the thermostability of the ''T.acidophilum'' citrate synthase. Therefore, it is assumed that “interface substitutions affecting the entropy of the unfolded state did not prove to be so critical in protein thermostabilization at higher temperatures.” (17)
[1. Darland, G. , Brock, T. D. , Samsonoff, W. & Conti, S. F. A thermophilic acidophilic mycoplasm isolated from a coal refuse pile. Science 170, 1416–1418 ( 1970).


2. Segerer, A. & Stetter, K. O. in The Prokaryotes (eds Balows, A., Trüper, H. G., Dworkin, M., Harder, W. & Schleifer, K. H.) 712–718 (Springer, New York, 1992).


3. Gutsche, I. , Essen, L. O. & Baumeister, W. Group II chaperonins: New TRiC(k)s and Turns of a Protein Folding Machine. J. Mol. Biol. 293, 295– 312 (1999).
A tremendous amount of research had been made on 20S proteasome of ''T.acidophilum'', because this enzyme is common in higher eukaryotic organism and can play an important role on medical research. (12) Scientists are trying to find a way to deregulate this enzymatic system which might help to suppress or cure cancer, because proteasomes are involved in apoptosis which plays a critical role in preventing cancer.(16)


4. Voges, D. , Zwickl, P. & Baumeister, W. The 26S proteasome: A molecular machine designed for controlled proteolysis. Annu. Rev. Biochem. 68, 1015–1068 (1999).  
==References==
1. NEWT/ NCBI
   
2. Brock, T. D., in Thermoplilic microorganisms and life at high temperatures, pp. 92-116 (Springer, Berlin Heidelberg New York).


5. Fleischmann, R. D. et al. Whole-genome random sequencing and assembly of Haemophilus influenzae Rd. Science 269, 496– 512 (1995).
3. Don Cowan,Nature 407, 466-467,28 September 2000


6. Himmelreich, R. et al. Complete sequence analysis of the genome of the bacterium Mycoplasma pneumoniae. Nucleic Acids Res. 24, 4420–4449 (1996).
4.Cedric F.V. Hobel, Sigillum Universitatis Islandiae, Access to Biodiversity and new genes from thermophiles by special enrichment methods, 2004


7. Yasuda, M. , Yamagishi, A. & Oshima, T. The plasmids found in isolates of the acidothermophilic archaebacterium Thermoplasma acidophilum. FEMS Microbiol. Lett. 128, 157–161 ( 1995).  
5. Budgen, N. & Danson, M. J. Metabolism of glucose via a modified Entner–Doudoroff pathway in the thermoacidophilic archaebacterium Thermoplasma acidophilum. FEBS Lett. 196, 207–210 (1986).
8. Lopez, P. , Philippe, H. , Myllykallio, H. & Forterre, P. Identification of putative chromosomal origins of replication in Archaea. Mol. Microbiol. 32, 881– 891 (1999).
 
6. Gutsche, I. , Essen, L. O. & Baumeister, W. Group II chaperonins: New TRiC(k)s and Turns of a Protein Folding Machine. J. Mol. Biol. 293, 295– 312 (1999).
9. Ree, H. K. R. & Zimmermann, R. A. Organization and expression of the 16S, 23S and 5S ribosomal RNA genes from the archaebacterium Thermoplasma acidophilum. Nucleic Acids Res. 18, 4471–4478 (1990).
 
10. Budgen, N. & Danson, M. J. Metabolism of glucose via a modified Entner–Doudoroff pathway in the thermoacidophilic archaebacterium Thermoplasma acidophilum. FEBS Lett. 196, 207–210 (1986).  


11. Searcy, D. G. & Whatley, F. R. Thermoplasma acidophilum: Glucose degradative pathways and respiratory activities. Syst. Appl. Microbiol. 5, 30–40 (1984).
7.Searcy, D. G. & Whatley, F. R. Thermoplasma acidophilum: Glucose degradative pathways and respiratory activities. Syst. Appl. Microbiol. 5, 30–40 (1984).  


12. Luebben, M. Cytochromes of archaeal electron transfer chains. Biochim. Biophys. Acta 1229, 1–22 ( 1995).  
8. Darland, G., Brock, T.D., Samsonoff, W. & Conti, S.F. A thermophilic acidophilic mycoplasm isolated from a coal refuse pile. Science 170, 1416-1418 (1970).  


13. Klenk, H. P. et al. The complete genome sequence of the hyperthermophilic, sulphate-reducing archaeon Archaeoglobus fulgidus. Nature 390, 364–370 (1997).
9. Zwickl, P. , Ng, D. , Woo, K. M. , Klenk, H. P. & Goldberg, A. L. An archaebacterial ATPase, homologous to ATPases in the eukaryotic 26 S proteasome, activates protein breakdown by 20 S proteasomes. J. Biol. Chem. 274, 26008– 26014 (1999).  


14. Huang, C. J. & Barret, E. L. Sequence Analysis and Expression of the Salmonella typhimurium asr Operon Encoding Production of Hydrogen Sulfide from Sulfite. J. Bacteriol. 173, 1544–1553 (1991).  
10. Voges, D. , Zwickl, P. & Baumeister, W. The 26S proteasome: A molecular machine designed for controlled proteolysis. Annu. Rev. Biochem. 68, 1015–1068 (1999).  


15. Rudolph, J. & Oesterhelt, D. Chemotaxis and phototaxis require a CheA histidine kinase in the archaeon Halobacterium salinarium. EMBO J. 14, 667–673 ( 1995).
11.Bijal P. Trivedi, T. acidophilum living the hot, acidic life, Genome News Network Sep 29, 2000


16. Coles, M . et al. The solution structure of VAT-N reveals a 'missing link' in the evolution of complex enzymes from a simple beta alpha beta beta element. Curr. Biol. 9, 1158–1168 (1999).
12. Keiji Tanaka and Tomoki Chiba, The proteasome: a protein-destroying machine, The Tokyo Mtropolitan Institute of Medical Science, 1998


17. Golbik, R. , Lupas, A. N. , Koretke, K. K. , Baumeister, W. & Peters, J. The janus face of the archaeal Cdc48/p97 homologue VAT: Protein folding versus unfolding. Biol. Chem. 380, 1049–1062 (1999).
13. Wolf S, Lottspeich F and Baumeister W, Ubiquitin found in the archaebacterium Thermoplasma acidophilum, 1993 Jul 12


18. Lupas, A. , Flanagan, J. M. , Tamura, T. & Baumeister, W. Self-compartmentalizing proteases. Trends Biochem. Sci. 22, 399–404 (1997).  
14. Mohamed, M. Optometry Professor. Smith, K. Optometrist. Sohn, S. Biomedical Science Professor.


19. Zwickl, P. , Ng, D. , Woo, K. M. , Klenk, H. P. & Goldberg, A. L. An archaebacterial ATPase, homologous to ATPases in the eukaryotic 26 S proteasome, activates protein breakdown by 20 S proteasomes. J. Biol. Chem. 274, 26008– 26014 (1999).  
15. J B Almond and G M Cohen, the proteasome: a novel target for cancer chemotherapy, Leukemia (2002) 16, 433-443. DOI: 10.1038/sj/leu/2402417


20. Tamura, N. , Lottspeich, F. , Baumeister, W. & Tamura, T. The role of Tricorn protease and its aminopeptidase-interacting factors in cellular protein degradation. Cell 95, 637 –648 (1998).
16. Murphy, KM et al (2000). "Bcl-2 inhibits Bax translocation from cytosol to mitochondria during drug-induced apoptosis of human tumor cells". Cell Death and Differentiation


21. Wolf, S. , Lottspeich, F. & Baumeister, W. Ubiquitin found in the archaebacterium Thermoplasma acidophilum. FEBS Lett. 326, 42– 44 (1993).
17. Erduran I.; Kocab y k S, Biochemical and Biophysical Research Communications, Volume 249, Number 2, August 1998, pp. 566-571(6)
 
22. Barrett, A. J. , Rawlings, N. D. & Woessner, J. F. Handbook of proteolytic enzymes (Academic, San Diego, CA, 1999).
 
23. Bergerat, A. et al. An atypical topoisomerase II from archaea with implications for meiotic recombination. Nature 386, 414 –417 (1997).
 
24. Stein, D. B. & Searcy, D. G. Physiologically important stabilization of DNA by a prokaryotic histone-like protein. Science 202, 219–221 (1978).
 
25. Hixon, W. G. & Searcy, D. G. Cytoskeleton in the archaebacterium Thermoplasma acidophilum? Viscosity increase in soluble extracts. BioSystems 29, 151–160 ( 1993).
 
26. Smith, P. F. , Langworthy, T. A. & Smith, M. R. Polypeptide nature of growth requirement in yeast extract for Thermoplasma acidophilum. J. Bacteriol. 124, 884–892 (1975).
 
27. Frishman, D. , Mironov, A. , Mewes, H. W. & Gelfand, M. Combining diverse evidence for gene recognition in completely sequenced bacterial genomes. Nucleic Acids Res. 26, 2941– 2947 (1998). 
 
28. Frishman, D. & Mewes, H. W. PEDANTic genome analysis. Trends Genet. 13, 415–416 (1997).
 
29. Altschul, S. F. et al. Gapped BLAST and PSI-BLAST: a new generation of protein database search programs. Nucleic Acids Res. 25, 3389–3402 (1997).
 
30. Koretke, K. K. , Russell, R. B. , Copley, R. R. & Lupas, A. N. Fold recognition using sequence and secondary structure information. Proteins Struct. Funct. Genet. 37, 141– 148 (1999).
 
31. Thermoplasma Genome Project, http://wwwex.biochem.mpg.de/baumeister/genome
 
32. Nature, http://www.nature.com/genomic/papers/thermoplasma.html]
 
33. Jose. O. Nazaria


18. Tokumasa Horiike, Kazuo Hamada and Takao Shinozawa. “Origin of Eukaryotic Cell Nuclei by Symbiosis of Archaea in Bacteria supported by the newly clarified origin of functional genes” Genes Genet. Syst. Vol. 77 369-376 (2002) .


--[[User:Chwon|chwon]] 22:00, 29 April 2007 (UTC)
--[[User:Chwon|chwon]] 22:00, 29 April 2007 (UTC)


Edited by student of [mailto:ralarsen@ucsd.edu Rachel Larsen] and Kit Pogliano
Edited by student of [mailto:ralarsen@ucsd.edu Rachel Larsen] and Kit Pogliano
KMG

Latest revision as of 15:19, 7 July 2011

This is a curated page. Report corrections to Microbewiki.

A Microbial Biorealm page on the genus Thermoplasma acidophilum

Classification

Higher order taxa

cellular organisms; Archaea; Euryarchaeota; Thermoplasmata; Thermoplasmatales; Thermoplasmataceae; Thermoplasma; Thermoplasma acidophilum

Genus

Thermoplasma acidophilum


NCBI: Taxonomy

Description and significance

Thermoplasma acidophilum. Linda Stannard, UCT/Photo Science Library.

Thermoplasma acidophilum is a thermophilic heterotrophic prokaryote and is "among the most acidophilic organism known.”(2) They grow at 55-60°C and favor a range pH of 0.5-4; It was found and first isolated from self-heating coal refuse piles and solfatara fields. (3)

Scientists have long been fascinated by the ability of this microorganism to grow at high temperatures and low pH, they are specially interested in the protein these organism have because common proteins are denatured under acidic and hot environments without the structural protection of a conventional cell wall.

Thermoplasma acidophilum’s genome contain special gene that allow this organism to survive in an environment similar in temperature and acidity to hot vinegar. (4) By determining and studying the genome sequence of this organism, we will develop a better understanding of protein folding and degradation; it will also present a more complete representation of the proteins involved in different system of our body. (3)

Genome structure

The genome of Thermoplasma is a single circular chromosome (1.56Mbp, containing 1509 ORFs)(4) and it is one of the smallest microbial genomes ever sequenced. (3)

alt Phylogenetic tree of 16S rRNA modified from Schleper et al., J. Bacteriol., 177: 7050-7059 (1995)

Surprisingly, the characteristics of Thermoplasma acidophilum’s small genome identify these organisms as a“typical euryarchaeon with a substantial complement of bacterial-related genes.” However,massive lateral gene transfer appears to have occurred between Thermoplasma and Sulfolobus solfataricus, "a phylogenetically distant crenarchaeon inhabiting the same environment." (2)

Cell structure and metabolism

Species of the genus Thermoplasma lack a rigid cell wall, but still have a plasma membrane, it is “devoid of protective outer shells (S-layer, cell wall), yet maintains a near-neutral cytosolic pH.” (4)


The lipid composition of T. acidophilum has been the subject of several investigations. This work has revealed the presence of “large polar lipids, often glycosylated with glucose, mannose and glucose, phosphorylated, or both, forming phosphoglycolipids” (5). These unusual lipid compositions allow T.acidophilum to survive under the harsh conditions of temperature and pH“restricting proton flow across the membrane more efficiently than non-branched lipids (6)” As the structure of branched lipid blocks the transport pathway of proton, neutral pH can be maintained within the cell membrane.


The Entner-Doudoroff pathway can only occur in prokaryotes like Thermoplasma. This pathway is a series of reactions that “catabolize glucose to pyruvate using a different set of enzymes other than those used in either glycolysis or the pentose phosphate pathway. A distinct feature of Entner-Doudoroff pathway is that it uses 6-phosphogluconate dehydrase and 2-keto-3-deoxyglucosephophate aldolase to create pyruvates from glucose." (14)

In Thermoplasma, glucose degradation is done by a “non-phosphorylated variant of the Entner–Doudoroff pathway, in which the first step is catalyzed by glucose dehydrogenase.” Acetyl-CoA produced from this pathway enters the TCA cycle. The presence of glycolysis/gluconeogenesis has not yet been confirmed due to the absence of phosphofructokinase and fructose in this organism. (7)

Ecology

Thermoplasma acidophilum plays an important role in the ecosystem. They act as scavengers in those extreme environment. “It has adapted to scavenging nutrients from the decomposition of organisms killed by the extreme acidity and requires yeast, bacterial or meat extract when grown in culture.” (3)


The study of Thermoplasma acidophilum indicate that an aqueous extract of coal refuse will serve as a nutrient source. This is the first step leading to the discovery of the materials in coal refuse which support its growth. Indeed, the coal refuse material provides nutrients for the growth of a wide variety of microorganisms and could be a source of new growth factors. (8)

Pathology

None of the archaea organisms, including Thermoplasma acidophilum, are known to cause disease in human beings.

Application to Biotechnology

Studies of the 20S proteasome from T.acidophilum has revealed that its proteolytic mechanism is similar to eukaryotic forms of the enzyme that are clinically relevant. (9)

In higher eukaryotes, the proteasome is involved in housekeeping and protein level regulation; Further understanding of the chemical mechanism of this enzyme can help us to understand diseases caused by the mutation of protesomes such as cystic fibrosis, Angelman's syndrome, Parkinson's disease, Liddle syndrome even cancer(10).

"Deregulation of this enzymatic system may also play a role in tumor progression, drug resistance, and altered immune surveillance, making the proteasome an appropriate and novel therapeutic target in cancer."(1) The proteasome is also involved in apoptosis, a process to safely dispose of cell corpses and fragment. Apoptosis is a main type of programmed cell death, it plays a critical role in preventing cancer; if a cell fails to undergo apoptosis, it can continue dividing and develop into tumor. (16)

Current Research

Origin of eukaryotic cell nuclei by symbiosis of archaea in bacteria supported by the newly clarified origin of functional genes of Thermoplasma acidophilum and 21 other unicellular organisms. This striking research suggests eukaryotic cell nuclei also undergo a process call endosymbiosis like mitochondria and chloroplast long time ago. Scientist did this by counting count the numbers of ORF (Orthologous ORFs were produced by speciation from a common ancestor, and have the highest similarity to each other); it was possible to detect the correct orthologous ORFs and to match up the origins of the functional categories in eukaryotic cells. Result find out there are lots of similarities between these two.(18)


The role of hydrophobic interactions in maintaining high temperature stability is investigated by citrate synthase of T.acidophilum as a thermostable model system. Scientists find that increasing or decreasing the hydrophobicity could further increase the thermostability of the T.acidophilum citrate synthase. Therefore, it is assumed that “interface substitutions affecting the entropy of the unfolded state did not prove to be so critical in protein thermostabilization at higher temperatures.” (17)


A tremendous amount of research had been made on 20S proteasome of T.acidophilum, because this enzyme is common in higher eukaryotic organism and can play an important role on medical research. (12) Scientists are trying to find a way to deregulate this enzymatic system which might help to suppress or cure cancer, because proteasomes are involved in apoptosis which plays a critical role in preventing cancer.(16)

References

1. NEWT/ NCBI

2. Brock, T. D., in Thermoplilic microorganisms and life at high temperatures, pp. 92-116 (Springer, Berlin Heidelberg New York).

3. Don Cowan,Nature 407, 466-467,28 September 2000

4.Cedric F.V. Hobel, Sigillum Universitatis Islandiae, Access to Biodiversity and new genes from thermophiles by special enrichment methods, 2004

5. Budgen, N. & Danson, M. J. Metabolism of glucose via a modified Entner–Doudoroff pathway in the thermoacidophilic archaebacterium Thermoplasma acidophilum. FEBS Lett. 196, 207–210 (1986).

6. Gutsche, I. , Essen, L. O. & Baumeister, W. Group II chaperonins: New TRiC(k)s and Turns of a Protein Folding Machine. J. Mol. Biol. 293, 295– 312 (1999).

7.Searcy, D. G. & Whatley, F. R. Thermoplasma acidophilum: Glucose degradative pathways and respiratory activities. Syst. Appl. Microbiol. 5, 30–40 (1984).

8. Darland, G., Brock, T.D., Samsonoff, W. & Conti, S.F. A thermophilic acidophilic mycoplasm isolated from a coal refuse pile. Science 170, 1416-1418 (1970).

9. Zwickl, P. , Ng, D. , Woo, K. M. , Klenk, H. P. & Goldberg, A. L. An archaebacterial ATPase, homologous to ATPases in the eukaryotic 26 S proteasome, activates protein breakdown by 20 S proteasomes. J. Biol. Chem. 274, 26008– 26014 (1999).

10. Voges, D. , Zwickl, P. & Baumeister, W. The 26S proteasome: A molecular machine designed for controlled proteolysis. Annu. Rev. Biochem. 68, 1015–1068 (1999).

11.Bijal P. Trivedi, T. acidophilum living the hot, acidic life, Genome News Network Sep 29, 2000

12. Keiji Tanaka and Tomoki Chiba, The proteasome: a protein-destroying machine, The Tokyo Mtropolitan Institute of Medical Science, 1998

13. Wolf S, Lottspeich F and Baumeister W, Ubiquitin found in the archaebacterium Thermoplasma acidophilum, 1993 Jul 12

14. Mohamed, M. Optometry Professor. Smith, K. Optometrist. Sohn, S. Biomedical Science Professor.

15. J B Almond and G M Cohen, the proteasome: a novel target for cancer chemotherapy, Leukemia (2002) 16, 433-443. DOI: 10.1038/sj/leu/2402417

16. Murphy, KM et al (2000). "Bcl-2 inhibits Bax translocation from cytosol to mitochondria during drug-induced apoptosis of human tumor cells". Cell Death and Differentiation

17. Erduran I.; Kocab y k S, Biochemical and Biophysical Research Communications, Volume 249, Number 2, August 1998, pp. 566-571(6)

18. Tokumasa Horiike, Kazuo Hamada and Takao Shinozawa. “Origin of Eukaryotic Cell Nuclei by Symbiosis of Archaea in Bacteria supported by the newly clarified origin of functional genes” Genes Genet. Syst. Vol. 77 369-376 (2002) .

--chwon 22:00, 29 April 2007 (UTC)

Edited by student of Rachel Larsen and Kit Pogliano

KMG

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