Sulfolobus is a genus of microorganism in the family Sulfolobaceae. It
belongs to the archaea domain.
Sulfolobus species grow in volcanic springs with optimal growth
occurring at pH 2-3 and temperatures of 75-80 °C, making them
acidophiles and thermophiles respectively.
Sulfolobus cells are
irregularly shaped and flagellar.
Sulfolobus are generally named after the location from
which they were first isolated, e.g.
Sulfolobus solfataricus was first
isolated in the Solfatara volcano. Other species can be found
throughout the world in areas of volcanic or geothermal activity, such
as geological formations called mud pots, which are also known as
solfatare (plural of solfatara).
Sulfolobus as a model to study the molecular mechanisms of DNA
2 Role in biotechnology
5 Cell structure and metabolism
7 DNA damage response
7.1 The ups operon
Sulfolobus as a viral host
9 See also
11 Further reading
11.1 Scientific journals
11.2 Scientific books
11.3 Scientific databases
12 External links
Sulfolobus as a model to study the molecular mechanisms of DNA
When the first Archaeal genome, Methanococcus jannaschii, had been
sequenced completely in 1996, it was found that the genes in the
genome of Methanococcus jannaschii involved in DNA replication,
transcription, and translation were more related to their counterparts
in eukaryotes than to those in other prokaryotes. In 2001, the first
genome sequence of Sulfolobus,
Sulfolobus solfataricus P2, was
published. In P2's genome, the genes related to chromosome replication
were likewise found to be more related to those in eukaryotes. These
genes include DNA polymerase, primase (including two subunits), MCM,
CDC6/ORC1, RPA, RPC, and PCNA. In 2004, the origins of DNA replication
Sulfolobus solfataricus and
Sulfolobus acidocaldarius were
identified. It showed that both species contained two origins in their
genome. This was the first time that more than a single origin of DNA
replication had been shown to be used in a prokaryotic cell. The
mechanism of DNA replication in archaea is evolutionary conserved, and
similar to that of eukaryotes.
Sulfolobus is now used as a model to
study the molecular mechanisms of DNA replication in Archaea. And
because the system of DNA replication in
Archaea is much simpler than
that in Eukaryota, it was suggested that
Archaea could be used as a
model to study the much more complex DNA replication in Eukaryota.
Role in biotechnology
Sulfolobus proteins are of interest for biotechnology and industrial
use due to their thermostable nature. One application is the creation
of artificial derivatives from S. acidocaldarius proteins, named
affitins. Intracellular proteins are not necessarily stable at low pH
Sulfolobus species maintain a significant pH gradient
across the outer membrane.
Sulfolobales are metabolically dependent on
sulfur: heterotrophic or autotrophic, their energy comes from the
oxidation of sulfur and/or cellular respiration in which sulfur acts
as the final electron acceptor. For example, S. tokodaii is known to
oxidize hydrogen sulfide to sulfate intracellularly.
The complete genomes have been sequenced for S. acidocaldarius DSM 639
(2,225,959 nucleotides), S. solfataricus P2 (2,992,245
nucleotides), and S. tokodaii str. 7 (2,694,756 nucleotides).
Sulfolobus solfataricus has a circular chromosome that
consists of 2,992,245 bp. Another sequenced species, S. tokodaii has a
circular chromosome as well but is slightly smaller with 2,694,756 bp.
Both species lack the genes ftsZ and minD, which has been
characteristic of sequenced Crenarchaeota. They also code for citrate
synthase and two subunits of 2-oxoacid:ferredoxin oxidoreductase,
which plays the same role as alpha-ketoglutarate dehydrogenase in the
TCA (tricarboxylic/Krebs/citric acid) cycle. This indicates that
Sulfolobus has a TCA cycle system similar to that found in
mitochondria of eukaryotes. Other genes in the respiratory chain which
partake in the production of ATP were not similar to what is found in
eukaryotes. Cytochrome c is one such example that plays an important
role in electron transfer to oxygen in eukaryotes. This was also found
in A. pernix K1. Since this step is important for an aerobic
microorganism like Sulfolobus, it probably uses a different molecule
for the same function or has a different pathway.
Cell structure and metabolism
Sulfolobus can grow either lithoautotrophically by oxidizing sulfur,
or chemoheterotrophically using sulfur to oxidize simple reduced
carbon compounds. Heterotrophic growth has only been observed,
however, in the presence of oxygen. The principle metabolic pathways
are a glycolytic pathway, a pentose phosphate pathway, and the TCA
Archaea have lipids with ether links between the head group and
side chains, making the lipids more resistant to heat and acidity than
bacterial and eukaryotic ester-linked lipids. The
known for unusual tetraether lipids.In Sulfolobales, the ether-linked
lipids are joined covalently across the "bilayer," making tetraethers.
Technically, therefore, the tetraethers form a monolayer, not a
bilayer. The tetraethers help
Sulfolobus species survive extreme acid
as well as high temperature.
S. solfataricus has been found in different areas including
Yellowstone National Park, Mount St. Helens, Iceland, Italy, and
Russia to name a few.
Sulfolobus is located almost wherever there is
volcanic activity. They thrive in environments where the temperature
is about 80 °C with a pH at about 3 and sulfur present. Another
species, S. tokodaii, has been located in an acidic spa in Beppu Hot
Springs, Kyushu, Japan. Sediments from ~90m below the seafloor on the
Peruvian continental margin are dominated by intact archaeal
tetraethers, and a significant fraction of the community is
sedimentary archaea taxonomically linked to the crenarchaeal
Sulfolobales (Sturt, et al., 2004).
DNA damage response
Sulfolobus solfataricus or
Sulfolobus acidocaldarius to
the DNA damaging agents UV-irradiation, bleomycin or mitomycin C
induced cellular aggregation. Other physical stressors, such as
pH or temperature shift, did not induce aggregation, suggesting that
induction of aggregation is caused specifically by DNA damage. Ajon
et al. showed that UV-induced cellular aggregation mediates
chromosomal marker exchange with high frequency in S. acidocaldarius.
Recombination rates exceeded those of uninduced cultures by up to
three orders of magnitude. Wood et al. also showed that
UV-irradiation increased the frequency of recombination due to genetic
exchange in S. acidocaldarius. Frols et al. and Ajon et al.
hypothesized that the UV-inducible DNA transfer process and subsequent
homologous recombinational repair represents an important mechanism to
maintain chromosome integrity in S. acidocaldarius and S.
solfataricus. This response may be a primitive form of sexual
interaction, similar to the more well-studied bacterial transformation
that is also associated with DNA transfer between cells leading to
homologous recombinational repair of DNA damage.
The ups operon
The ups operon 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. 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. It was proposed that
Saci-1497 and Saci-1500 function in an homologous recombination-based
DNA repair mechanism that uses transferred DNA as a template. Thus
it is thought that the ups system in combination with homologous
recombination provide a DNA damage response which rescues Sulfolobales
from DNA damaging threats.
Sulfolobus as a viral host
Lysogenic viruses infect
Sulfolobus for protection. The viruses cannot
survive in the extremely acidic and hot conditions that Sulfolobus
lives in, and so the viruses use
Sulfolobus as protection against the
harsh elements. This relationship allows the virus to replicate inside
the archaea without being destroyed by the environment. The Sulfolobus
viruses are temperate or permanent lysogens. Permanent lysogens differ
from lysogenic bacteriophages in that the host cells are not lysed
after the induction of Fuselloviridae production and eventually return
to the lysogenic state. They are also unique in the sense that the
genes encoding the structural proteins of the virus are constantly
transcribed and DNA replication appears to be induced. The viruses
infecting archaea like
Sulfolobus have to use a strategy to escape
prolonged direct exposure to the type of environment their host lives
in, which may explain some of their unique properties.
Evolution of sexual reproduction
^ See the NCBI webpage on Sulfolobus. Data extracted from the "NCBI
taxonomy resources". National Center for Biotechnology Information.
^ Chen, L; Brügger, K; Skovgaard, M; Redder, P; She, Q; Torarinsson,
E; Greve, B; Awayez, M; Zibat, A; Klenk, HP; Garrett, RA (July 2005).
"The genome of
Sulfolobus acidocaldarius, a model organism of the
Crenarchaeota". Journal of Bacteriology. 187 (14): 4992–9.
doi:10.1128/JB.187.14.4992-4999.2005. PMC 1169522 .
^ She, Q; Singh, RK; Confalonieri, F; Zivanovic, Y; Allard, G; Awayez,
MJ; Chan-Weiher, CC; Clausen, IG; Curtis, BA; De Moors, A; Erauso, G;
Fletcher, C; Gordon, PM; Heikamp-de Jong, I; Jeffries, AC; Kozera, CJ;
Medina, N; Peng, X; Thi-Ngoc, HP; Redder, P; Schenk, ME; Theriault, C;
Tolstrup, N; Charlebois, RL; Doolittle, WF; Duguet, M; Gaasterland, T;
Garrett, RA; Ragan, MA; Sensen, CW; Van der Oost, J (3 July 2001).
"The complete genome of the crenarchaeon
Sulfolobus solfataricus P2".
Proceedings of the National Academy of Sciences of the United States
of America. 98 (14): 7835–40. doi:10.1073/pnas.141222098.
PMC 35428 . PMID 11427726.
^ Kawarabayasi, Y; Hino, Y; Horikawa, H; Jin-no, K; Takahashi, M;
Sekine, M; Baba, S; Ankai, A; Kosugi, H; Hosoyama, A; Fukui, S; Nagai,
Y; Nishijima, K; Otsuka, R; Nakazawa, H; Takamiya, M; Kato, Y;
Yoshizawa, T; Tanaka, T; Kudoh, Y; Yamazaki, J; Kushida, N; Oguchi, A;
Aoki, K; Masuda, S; Yanagii, M; Nishimura, M; Yamagishi, A; Oshima, T;
Kikuchi, H (31 August 2001). "Complete genome sequence of an aerobic
Sulfolobus tokodaii strain7". DNA
research : an international journal for rapid publication of
reports on genes and genomes. 8 (4): 123–40.
doi:10.1093/dnares/8.4.123. PMID 11572479.
^ a b c Ajon M; Fröls S; van Wolferen M; et al. (November 2011).
"UV-inducible DNA exchange in hyperthermophilic archaea mediated by
type IV pili". Mol. Microbiol. 82 (4): 807–17.
doi:10.1111/j.1365-2958.2011.07861.x. PMID 21999488.
^ a b c Fröls S; Ajon M; Wagner M; et al. (November 2008).
"UV-inducible cellular aggregation of the hyperthermophilic archaeon
Sulfolobus solfataricus is mediated by pili formation". Mol.
Microbiol. 70 (4): 938–52. doi:10.1111/j.1365-2958.2008.06459.x.
^ Wood ER; Ghané F; Grogan DW (September 1997). "Genetic responses of
the thermophilic archaeon
Sulfolobus acidocaldarius to
short-wavelength UV light". J. Bacteriol. 179 (18): 5693–8.
PMC 179455 . PMID 9294423.
^ Fröls S; White MF; Schleper C (February 2009). "Reactions to UV
damage in the model archaeon
Sulfolobus solfataricus". Biochem. Soc.
Trans. 37 (Pt 1): 36–41. doi:10.1042/BST0370036.
^ Gross J; Bhattacharya D (2010). "Uniting sex and eukaryote origins
in an emerging oxygenic world". Biol. Direct. 5: 53.
doi:10.1186/1745-6150-5-53. PMC 2933680 .
^ Bernstein, H; Bernstein, C (2010). "Evolutionary Origin of
Recombination during Meiosis". BioScience. 60 (7): 498–505.
^ Harris Bernstein, Carol Bernstein and Richard E. Michod (2011).
Meiosis as an Evolutionary Adaptation for DNA Repair. Chapter 19 in
DNA Repair. Inna Kruman editor. InTech Open Publisher.
^ a b c van Wolferen M, Ma X, Albers SV (2015). "DNA Processing
Proteins Involved in the UV-Induced Stress Response of Sulfolobales".
J. Bacteriol. 197 (18): 2941–51. doi:10.1128/JB.00344-15.
PMC 4542170 . PMID 26148716.
Madigan M; Martinko J, eds. (2005). Brock Biology of Microorganisms
(11th ed.). Prentice Hall. ISBN 0-13-144329-1.
Judicial Commission of the International Committee on Systematics of
Prokaryotes (2005). "The nomenclatural types of the orders
Acholeplasmatales, Halanaerobiales, Halobacteriales,
Methanobacteriales, Methanococcales, Methanomicrobiales,
Planctomycetales, Prochlorales, Sulfolobales, Thermococcales,
Thermoproteales and Verrucomicrobiales are the genera Acholeplasma,
Halanaerobium, Halobacterium, Methanobacterium, Methanococcus,
Methanomicrobium, Planctomyces, Prochloron, Sulfolobus, Thermococcus,
Thermoproteus and Verrucomicrobium, respectively. Opinion 79". Int. J.
Syst. Evol. Microbiol. 55 (Pt 1): 517–518.
doi:10.1099/ijs.0.63548-0. PMID 15653928.
Brock TD; Brock KM; Belly RT; Weiss RL (1972). "Sulfolobus: a new
genus of sulfur-oxidizing bacteria living at low pH and high
temperature". Arch. Mikrobiol. 84 (1): 54–68.
doi:10.1007/BF00408082. PMID 4559703.
Stetter, KO (1989). "Order III.
Sulfolobales ord. nov. Family
Sulfolobaceae fam. nov.". In JT Staley; MP Bryant; N Pfennig; JG Holt.
Bergey's Manual of Systematic Bacteriology. 3 (1st ed.). Baltimore:
The Williams & Wilkins Co. p. 169.
PubMed references for Sulfolobus
PubMed Central references for Sulfolobus
Google Scholar references for Sulfolobus
NCBI taxonomy page for Sulfolobus
Search Tree of Life taxonomy pages for Sulfolobus
Search Species2000 page for Sulfolobus
MicrobeWiki page for Sulfolobus
LPSN page for Sulfolobus
Comparative Analysis of
Sulfolobus Genomes (at DOE's IMG system)
Genome Projects (from Genomes OnLine Database)