Sulfolobus acidocaldarius

A Microbial Biorealm page on the genus Sulfolobus acidocaldarius

Classification

Higher order taxa

Archaea; Crenarchaeota; Thermoprotei; Sulfolobales; Sulfolobaceae; Sulfolobus

Species

Sulfolobus acidocaldarius Strain DSM639

Description and significance

Sulfolobus acidocaldarius is an aerobic thermoacidophilic crenarchaeon which grows optimally at 80°C and pH 2 in terrestrial solfataric springs. [1] They are primarily an aquatic organism; highly abundance in sulfur-rich hot acid springs in Yellowstone National Park. Sulfolobus are likely to be present in most hot springs [6]. The strictly aerobic organism also establishes itself in hot acid soils at temperatures 55-85°C. [3] Sulfolobus acidocaldarius is responsible for the oxidation of sulfur in sulfuric acid production and the existence of sulfur-oxidizing bacteria. [3]

Sulfolobus acidocaldarius strain DSM639, the type strain of the archaeal genus Sulfolobus, was the first hyperthermoacidophile to be characterized from terrestrial solfataras. [1] They serve as a model organism for the Phylum Crenarchaeota and have been used for many studies in archaeal biology.

Genome structure

Shotgun sequencing was used to map the genome for Sulfolobus acidocaldarious strain DSM639. The circular genome was sequence to carry 2,225,950 bp (37% G+C), with 2,292 predicted protein encoding genes [1]. Within the 2,292 protein encoding genes, 305 are exclusive to Sulfolobus acidocaldarius and 866 genes are specific to Genus Sulfolobus [1].

133 short genes were identified by comparing all DNA sequence analysis with the other Sulfolobus genomes [1]. The 133 shorter genes appeared in multiple copies, there is a total of 95 different genes [1]. Inteins were not found [1].

Cell structure and metabolism

Sulfolobus acidocaldarius grows under strictly aerobic conditions on complex organic substrates, including yeast extract, tryptone, and Casamino Acids, a wide range of amino acids, and a limited number of sugars (carbon sources) [1]. Sulfolobus acidocaldarius has three unique enzymes that allow the organism to grow on carbon sources. These includes a homolog of the bacterial enzyme to degrade poly(3-hydroxyalkanotes), a special transporter for malate and other C4-dicarboxylates, and two subunits of an aromatic ring dioxygenase to degrade simple aromatic ring compounds [1].

As in the other two Sulfolobus genomes, Sulfolobus acidocaldarius is encoded to carry the enzyme for metabolizing sulfur which yields sulfuric acid from hydrogen sulfide via a conserved sulfur locus [1].

To occupy such an extreme environment efficiently, Sulfolobus acidocaldarius has unique features which allow them to live in hot and acidic springs. They are capable of direct removal of DNA damage, base excision repair, nucleotide excision repair, and homolog-dependent double-strand-break repair [1]. Sulfolobus acidocaldarius has a fairly short mRNA half-life distribution, similar to those of fast growing bacteria, which meets the need for rapidly reprogram gene expression upon sudden changes in the environment [4].

In addition, the organism carries an apparatus for ultraviolet damage excision repair in its genome, the UV damage endonuclease [1]. Furthermore, motility away from lethal hot spots is observed, even in the absence of carbon and energy source [2]. This temperature sensitive motility is an important survival mechanism unique for Sulfolobus acidocaldarius in the hydrothermal environment [2].

Sulfolobus acidocaldarius has facilitated archaeal cell cycle studies, not only with its very stable genome organization, but also its special ability to exchange chromosomal genes intercellularly and its capacity to grow synchronously in culture [1].

Ecology

Sulfolobus acidocaldarius are abundant in Yellowstone Park’s sulfur-rich hot acid springs at temperature 70-80°C [1]. They occur in high numbers attaching to the surface of sulfur crystals [3]. Sulfolobus acidocaldarius oxidizes sulfur to sulfuric acid and they are responsible for the sulfuric acid concentration in the aquatic enviornment [3]. Such acidic conditions do not allow for organism interactions in nature.

When acidic springs are absent, solfatara soils and mud pots (due to the microbial oxidation of sulfuric acid) are heated by rising streams to various temperatures [3]. Solfatara soil is the home to Thiobacillus thiooxidans, as well as Sulfolobus acidocaldarius [3]. Both of these organisms are found in a pH range of 0.9-5.9, however, temperature plays the role in their separation. Sulfolobus acidocaldarius is found only at temperatures 55 °C and above, whereas Thiobacillus thiooxidans resides in soil below 55 °C. The thermoacidophile isolates itself in its optimal environments.

Sulfolobus acidocaldarius strain B12 is known to be a viral host [7].

Pathology

Sulfolobus acidocaldarius is currently not known to cause any human diseases.

Sulfolobus serves as a host to lysogenic viruses. The viruses infect Sulfolobus to survive in the extremely acidic environment. Sulfolobus acidocaldarius, strain B12, harbors a double-stranded DNA species both as a plasmid and in a linear form, and produces virus-like particles, SAV 1, upon Ultraviolet radiation [7]. The host cell recovers and remains lysogenic after the viral production; virus is thus release into nature [7]. Although viral particles are found attached to the cells, neither adsorption nor infection has been observed [7].

Application to Biotechnology

Extreme thermophiles have always been of great interest of studies because of its thermostable abilities. Sulfolobus acidocaldarius has aid in the studies of chromatin-binding proteins, replication, cell cycle, repair, transcription, translation, as well as metabolism [5]. Moreover, its sensitivity to a wide range of ribosomal antibiotics and ease of transformation has rendered Sulfolobus acidocaldarius a focus for in vivo genetic studies [1]. It is the only hyperthermophilic archaeon with a spontaneous mutation rate quantified in vivo [1].

Sulfolobus acidocaldarius stirs high interests with its low mutation rate at high temperature environment with its strong efficient repair systems [1]. By studying less complex archaeal systems, Sulfolobus acidocaldarius serves as a model in the understanding of more intricate eukaryote systems.

Current Research

Enter summaries of the most recent research here--at least three required

References

1. Lanming Chen, Kim Brügger, Marie Skovgaard, Peter Redder, Qunxin She, Elfar Torarinsson, Bo Greve, Mariana Awayez, Arne Zibat, Hans-Peter Klenk, and Roger A. Garrett. “The Genome of Sulfolobus acidocaldarius, A Model Organism of the Crenarchaeota”. Journal of Bacteriology, July 2005. 187(14):. p. 4992–4999. [1]

2. Paul Lewus and Roseanne M. Ford. “Temperature-Sensitive Motility of Sulfolobus acidocaldarius Influences Population Distribution in Extreme Environments”. Journal of Bacteriology. July 1999. 181(13): 4020–4025. [2]

3. Carl B. Fliermans and Thomas D. Brock. “Ecology of Sulfur-Oxidizing Bacteria in Hot Acid Soils”. Journal of Bacteriology, Aug 1972. p. 343-350. [3]

4. Anders F Andersson, Magnus Lundgren, Stefan Eriksson, Magnus Rosenlund, Rolf Bernander, and Peter Nilsson. “Global analysis of mRNA stability in the archaeon Sulfolobus”. Genome Biology. 2006; 7(10): R99. [4]

5. Silvia Berkner, Dennis Grogan, Sonja-Verena Albers, and Georg Lipps. “Small multicopy, non-integrative shuttle vectors based on the plasmid pRN1 for Sulfolobus acidocaldarius and Sulfolobus solfataricus, model organisms of the (cren-)archaea”. Nucleic Acids Research. 2007 June; 35(12): e88. [5]

6. George Rice, Kenneth Stedman, Jamie Snyder, Blake Wiedenheft, Debbie Willits, Susan Brumfield, Timothy McDermott, and Mark J. Young. "Viruses from extreme thermal environments". Proceedings National Academy of Sciences of the Unites States of America. 2001 November 6; 98(23): 13341–13345. [6]

7. Andrea Martin, Siobhan Yeats, Davorin Janekovic, Wolf-Dieter Reiter, Wilhelm Aicher, and Wolfram Zillig. "SAV 1, A Temperate U.V.-Inducible DNA virus-like particle from the Archaebacterium Sulfolobus acidocaldarius isolate B12". The EMBO Journal vol.3 no.9 pp.2165-2168, 1984. [7]

8. NCBI Taxonomy Broswer. "Sulfolobus acidocaldarius DSM 639". [8]

Edited by Fanny Wong of Rachel Larsen