''Sulfolobus acidocaldarius'' is a
thermoacidophilic archaeon
Archaea ( ; singular archaeon ) is a domain of single-celled organisms. These microorganisms lack cell nuclei and are therefore prokaryotes. Archaea were initially classified as bacteria, receiving the name archaebacteria (in the Archaebact ...
that belongs to the phylum
Thermoproteota. ''S. acidocaldarius'' was the first ''Sulfolobus'' species to be described, in 1972 by
Thomas D. Brock and collaborators.
This species was found to grow optimally between 75 and 80 °C, with pH optimum in the range of 2-3.
Isolation
''Sulfolobus acidocaldarius'' was first isolated from thermal soils and hot springs with low pH in the United States of America (specifically in the Yellowstone National Park), in El Salvador,
Dominica and Italy. The springs where this species was isolated had a pH less than 3 and temperatures in the range of 65-90 °C.
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Morphological description
''Sulfolobus acidocaldarius'' is, as all Archaea, unicellular. Cells belonging to this species are spherical, albeit irregular, and usually possess lobes. The diameter of the cells fall in the range of 0.8-1 μm, with little size variation.[
]
Cell replication
''Sulfolobus acidocaldarius'' possess a mechanism of replication homologous to the eukaryotic ESCRT The endosomal sorting complexes required for transport (ESCRT) machinery is made up of cytosolic protein complexes, known as ESCRT-0, ESCRT-I, ESCRT-II, and ESCRT-III. Together with a number of accessory proteins, these ESCRT complexes enable a uni ...
.
Metabolism
''Sulfolobus acidocaldarius'' is a facultative autotroph
An autotroph or primary producer is an organism that produces complex organic compounds (such as carbohydrates, fats, and proteins) using carbon from simple substances such as carbon dioxide,Morris, J. et al. (2019). "Biology: How Life Wo ...
. When growing autotrophically this organism oxidises sulfur to sulfate, while fixating carbon from carbon dioxide. The doubling time of cultures growing on sulfur alone falls between 36.8-55.3h.
This species can also grow on complex organic substrates. When growing on 0.1% yeast extract the growth is faster, and the doubling times are between 6.5 and 8h.[
]
Genome
In 2005 the complete genome of ''Sulfolobus acidocaldarius'' strain DSM639 was published. The genome of this archaeon is composed of a single circular chromosome with 2,225,959 bp, with a G+C content
G, or g, is the seventh letter in the Latin alphabet, used in the modern English alphabet, the alphabets of other western European languages and others worldwide. Its name in English is ''gee'' (pronounced ), plural ''gees''.
History
Th ...
of 36.7%. The authors predicted 2292 protein-coding genes. The genome of ''Sulfolobus acidocaldarius'' is very stable, with little, if any, rearrangements due to mobile elements.
The authors found the genes necessary for the synthesis of purines and pyrimidines, as well as for all amino acids except for selenocysteine. Genes for glucose metabolism suggest the existence of two alternative pathways. This ''Sulfolobus'' species grows on a limited range of carbon sources, relative to other ''Sulfolobus'' species, and this might be due to the lack of adequate transporters.
The ''ups'' operon
UV-irradiation increases the frequency of recombination due to genetic exchange in ''S. acidocaldarius''.operon
In genetics, an operon is a functioning unit of DNA containing a cluster of genes under the control of a single promoter. The genes are transcribed together into an mRNA strand and either translated together in the cytoplasm, or undergo splic ...
of ''Sulfolobus'' species is highly induced by UV irradiation. The pili encoded by this operon are employed in promoting cellular aggregation, which is necessary for subsequent DNA exchange between cells, resulting in homologous recombination
Homologous recombination is a type of genetic recombination in which genetic information is exchanged between two similar or identical molecules of double-stranded or single-stranded nucleic acids (usually DNA as in cellular organisms but may ...
. A study of the ''Sulfolobales acidocaldarius ups'' operon showed that one of the genes of the operon, ''saci-1497'', encodes an endonuclease III that nicks UV-damaged DNA; and another gene of the operon, ''saci-1500'', encodes a RecQ-like helicase that is able to unwind homologous recombination intermediates such as Holliday junctions.
Significance
The thermostable restriction enzyme ''Sua''I is obtained from this organism.
References
External links
Type strain of ''Sulfolobus acidocaldarius'' at Bac''Dive'' - the Bacterial Diversity Metadatabase
Evolutionary Insight: New Connection Discovered Between Primordial Organisms and Complex Life
on: SciTechDaily; August 28, 2020; source: Lancaster University
* Gabriel Tarrason Risa, Fredrik Hurtig, Sian Bray, Anne E. Hafner, Lena Harker-Kirschneck, Peter Faull, Colin Davis, Dimitra Papatziamou, Delyan R. Mutavchiev, Catherine Fan, Leticia Meneguello, Andre Arashiro Pulschen, Gautam Dey, Siân Culley, Mairi Kilkenny, Diorge P. Souza, Luca Pellegrini, Robertus A. M. de Bruin, Ricardo Henriques, Ambrosius P. Snijders, Andela Šaric, Ann-Christin Lindås, Nicholas P. Robinson, Buzz Baum: “The proteasome controls ESCRT-III–mediated cell division in an archaeon”; In: Science; 7 August 2020; doi:10.1126/science.aaz2532
{{Taxonbar, from=Q2364491
Thermoproteota
Archaea described in 1972