Sulfolobus Species Research Articles

A potential anti-oxidant protein in a ferrous iron-oxidizing Sulfolobus species.

The production of a 25 kDa protein was greatly increased when a sulfur- and ferrous iron-oxidizing species of Sulfolobus was switched from growth on tetrathionate to growth on ferrous iron. The gene encoding the protein was cloned and sequenced. The predicted amino sequence showed significant similarity to those of the alkyl hydroperoxide reductase/thiol specific anti-oxidant family of proteins that appear to be involved in responses to certain types of oxidative stress.

Characterization and identification of thermoacidophilic archaebacteria isolated in Japan.

Three isolates of spherical thermoacidophilic archaebacteria (strains TA-1, TA-2 and N-8) were obtained from acidic hot springs at Hakone and Noboribetsu in Japan. We have studied the isolates using electron microscopy, Gram staining, sensitivity to lysozyme, growth conditions, lipid compositions, SDS-PAGE patterns of whole-cell proteins, DNA base composition and partial 16S rRNA sequences. These characteristics of the isolates were compared with those of the type strains, Sulfolobus acidocaldarius, Sulfolobus solfataricus, Acidianus brierleyi, Acidianus infernus, Metallosphaera sedula and Desulfurolobus ambivalens. Comparative studies indicated that the isolate TA-1 was novel species of either Sulfolobus or Acidianus, the isolate TA-2 belonged to the genus Metallosphaera, and the isolate N-8 belonged to the same species of S. acidocaldarius isolated from Yellowstone.

An insertion element of the extremely thermophilic archaeon Sulfolobus solfataricus transposes into the endogenous beta-galactosidase gene.

Three phenotypically stable mutants of the extremely thermophilic archaeon Sulfolobus solfataricus have been isolated by screening for beta-galactosidase negative colonies on plates with X-Gal (5-bromo-4-chloro-3-indolyl-beta-D- galactopyranoside). From one of these mutants an insertion element, designated ISC1217, was isolated and characterized. Sequence analysis of ISC1217 and of the regions adjacent to the insertion site in the beta-galactosidase gene revealed features typical of a transposable element: ISC1217 contained terminal inverted repeats and was flanked by a direct repeat of 6 bp. The 1147 bp sequence contained an open reading frame encoding a putative protein of 354 amino acid residues and, overlapping this, two smaller open reading frames on the opposite strand. There were approximately 8 copies of the insertion element in the S. solfataricus genome. ISC1217 did not cross-hybridize with DNA of other Sulfolobus species. All three independently isolated beta-galactosidase mutants of S. solfataricus arose by transposition of ISC1217 or a related element.

Isolate B12, which harbours a virus-like element, represents a new species of the archaebacterial genus Sulfolobus, Sulfolobus shibatae, sp. nov.

The Sulfolobus isolate B12 and its endogenous virus-like element SSV1 have provided a fruitful system for detailed analysis of certain aspects of archaebacterial molecular biology, especially those concerning gene expression. In the course of clarifying this isolate's taxonomic position, we determined DNA base composition, ability to grow autotrophically, nucleotide sequence of 16S ribosomal RNA, and level of total genomic homology to other Sulfolobus strains. Although the results generally demonstrate a similarity to S. solfataricus, DNA-DNA hybridisation and 16S rRNA sequence data indicate that isolate B12 in fact represents a distinct species.

Acquired thermotolerance and heat shock in the extremely thermophilic archaebacterium Sulfolobus sp. strain B12

The extreme thermophile Sulfolobus sp. strain B12 exhibits an acquired thermotolerance response. Thus, survival of cells from a 70 degrees C culture at the lethal temperature of 92 degrees C was enhanced by as much as 6 orders of magnitude over a 2-h period if the culture was preheated to 88 degrees C for 60 min or longer before being exposed to the lethal temperature. In eubacteria and eucaryotes, acquired thermotolerance correlates with the induced synthesis of a dozen or so proteins known as heat shock proteins. In this Sulfolobus species, it correlates with the preferential synthesis of primarily one major protein (55 kilodaltons) and, to a much lesser extent, two minor proteins (28 and 35 kilodaltons). Since the synthesis of all other proteins was radically reduced and these proteins were apparently not degraded or exported, their relative abundance within the cell increased during the time the cells were becoming thermotolerant. They could not yet be related to known heat shock proteins. In immunoassays, they were not cross-reactive with antibodies against heat shock proteins from Escherichia coli (DnaK and GroE), which are highly conserved between eubacteria and eucaryotes. However, it appears that if acquired thermotolerance depends on the synthesis of protective proteins, then in this extremely thermophilic archaebacterium it depends primarily on one protein.

Biosynthesis of caldariellaquinone in Sulfolobus spp

The biosynthesis of caldariellaquionone (CQ) was studied in species of Sulfolobus by measuring the incorporation of stable isotopically labeled tyrosines into CQ. By feeding a series of tyrosines labeled with deuterium or 13C and then measuring the extent and position at which label was incorporated into CQ by mass spectrometry, it was shown that more than 95% of the label was incorporated into the benzo[b]thiophen-4,7-quinone moiety of CQ. From the labeling experiments, it is concluded that the benzo[b]thiophen-4,7-quinone is derived as an intact unit from all of the carbons of tyrosine except C-1.

Microorganisms for desulphurization of coal: the influence of leaching compounds on their growth

An investigation was undertaken to outline how microorganisms suggested for use in coal desulphurization are affected by compounds leached from coal. Three species of the genus Sulfolobus were studied. Sulfolobus acidocaldarius was seen to be affected by compounds leached from coal more negatively than Sulfolobus brierleyi and Sulfolobus solfataricus. It was observed that certain conditions during leaching, such as pH, temperature and leaching time, were important for the concentration of compounds leached from coal. It was seen that compounds leached from coal, in some cases, can improve the growth yield for the microorganisms.

Distribution of charged pterins in nonmethanogenic archaebacteria

Pterin content was surveyed in nine species of nonmethanogenic archaebacteria comprised of six species of halobacteria, two species of Sulfolobus, and one specie of Thermoplasma. The results indicated the presence of the sulfate-containing dimeric pterin sulfohalopterin-2 in three species of halobacteria, “Halobacterium marismortui”, halobacterial strain GN-1, and Halobacterium volcanii. The phosphate-containing dimeric pterin phosphohalopterin-1 was present in three other species of halobacteria, Halobacterium salinarium, Halobacterium halobium, and Halococcus morrhuae. Evidence is presented that these halopterins exist in the halobacteria as tetrahydropterin derivatives. A positively charged monomeric pterin, solfapterin (erythro-neopterin-3′-D-2-deoxy-2-aminoglucopyranoside), was found to be present in Sulfolobus solfataricus and a negatively charged pterin was induced when S. solfataricus was grown in a medium containing homogentisic acid (2,5-dihydroxyphenylacetic acid). This negatively charged pterin was not present when the cells were grown in the normal medium. Another positively charged pterin found in Thermoplasma was determined to be different from solfapterin based on its paper electrophoresis properties. Uncharged pterins were also identified in all of these bacteria, however, no attempt was made to elucidate the structure of these uncharged pterins. Pterin content was found to vary in the different bacteria and to depend on the conditions under which the cells were grown.

Surface structure variants in different species of Sulfolobus

Surface structure variants in different species of Sulfolobus

Surface structure variants in different species of Sulfolobus

The regularly arrayed surface proteins of 5 species or isolates, all belonging to the Sulfolobales, were investigated in situ by freeze-etching. Surface relief reconstructions reveal a species specificity of the surface protein on the level of the domain structure which correlates well with the phylogenetic status.

Acidianus infernus gen. nov., sp. nov., and Acidianus brierleyi Comb. nov.: Facultatively Aerobic, Extremely Acidophilic Thermophilic Sulfur-Metabolizing Archaebacteria

A new genus, Acidianus, is characterized from studies of 26 isolates of thermoacidophilic archaebacteria from different solfatara fields and marine hydrothermal systems; these isolates grow as facultative aerobes by lithotrophic oxidation and reduction of SO, respectively, and are therefore different from the strictly aerobic Sulfolobus species. The Acidianus isolates have a deoxyribonucleic acid guanine-plus-cytosine content of 31 mol%. In contrast, two of three Sulfolobus species, including the type species, have a guanine-plus-cytosine content of 37 mol%; Sulfolobus brierleyi is the exception, with a guanine-plus-cytosine content of 31 mol%. In contrast to its earlier descriptions, S. brierleyi is able to grow strictly anaerobically by hydrogen-sulfur autotrophy. Therefore, it is described here as a member of the genus Acidianus. The following species are assigned to the genus Acidianus: Acidianus infernus sp. nov. (type strain, strain DSM 3191) and Acidianus brierleyi comb. nov. (type strain, strain DSM 1651).

Archaebacterial ether lipids and chemotaxonomy

Summary The uniqueness of archaebacterial lipids is an important factor in placing these organisms on a separate evolutionary path. Isopranyl glycerol ethers make up the hydrophobic core of the archaebacterial membrane rather than the fatty acid ester-linked glycerol lipids which predominate in the membranes of eubacterial and eukaryotic cells. Furthermore, the optical activity characteristic of the central carbon of glycerol, and the major pathway for lipid biosynthesis in archaebacteria are the opposite to the case in the other two primary kingdoms. These considerations imply important differences in the construction of the archaebacterial membrane. The hydrocarbon chains of the glycerol ethers are isopranoid branched and almost invariably fixed at a chain length of either 20- or 40-carbon atoms. Phytanyl diethers containing two C20 phytanyl chains appear to be universal components in those archaebacteria thus far examined. Dibiphytanyl diglycerol tetraethers that contain two C40 biphytanyl chains ether-linked to two glycerol molecules are also major components although they are not common to all archaebacteria. They occur in many methanogenic, thermophilic and thermoacidophilic archaebacteria but have not yet been found in the extreme halophiles. Thus far, few exceptions to the two basic glycerol ether structures are known to occur in archaebacteria. Haloalkalophilic archaebacteria have been shown to possess diethers that contain a C20 phytanyl and a C25 sesterterpanyl chain and diethers that possess two C25 sesterterpanyl chains, in addition to the usual diethers. One thermophilic methanogen, Methanococcus jannaschi, has been shown to contain a diether possessing a C40 biphytanyl macrocyclic loop as a major component. Two exceptions to the basic diglycerol tetraether structure occur in Sulfolobus species. In addition to the usual tetraethers, these organisms have large amounts of nonitolglycerol tetraethers in which a nine carbon nonitol substitutes for one of the two glycerol molecules. Small amounts of a tetraether containing one C40 bibphytanyl chain and two C20 phytanyl chains are also present. The general invariability of the isopranyl glycerol ethers can serve as a convenient molecular marker for supporting the identification of an organism as an archaebacterium. Utilization of such a marker in attempting to identify new organisms as archaebacteria has also uncovered a variety of unusual new lipids in other organisms which should prove useful in assessing evolutionary relationships among eubacteria.

Plasmid-related anaerobic autotrophy of the novel archaebacterium Sulfolobus ambivalens.

Three different species of the genus Sulfolobus, S. acidocaldarius, S. solfataricus (= Caldariella) and S. brierleyi, have been distinguished by the conditions required for optimal growth, by the component patterns of their DNA-dependent RNA polymerases and by DNA sequence data. Many isolates of these species are able to grow chemolithoautotrophically using CO2 as the sole carbon source and the oxidation of S(0) with O2 yielding sulphuric acid, as the energy source, though a few others grow only heterotrophically. We show here that a strain of a novel Sulfolobus species, S. ambivalens, is alternatively able to live by an anaerobic mode of chemolithoautotrophy, also using CO2 as the sole carbon source, but using reduction of S(0) with H2, yielding H2S as the energy source. This mode of growth is correlated with the amplification of a plasmid, pSL10.

Anaerobic Reduction of Molybdenum by Sulfolobus Species

The acidothermophilic Archaebacteria, Sulfolobus acidocaldarius and S. brierleyi , oxidized elemental sulfur anaerobically producing sulfuric acid by using Mo (VI) as an apparent electron acceptor. Molybdenum reduction resulted in the formation of a blue color which was intensified in the presence of aluminum at concentrations of 20–50 mM. Molybdenum was not reduced when S. brierleyi was grown anaerobically on yeast extract as an energy source, suggesting that the organic substrate was utilized in a fermentative metabolism mode.

The Sulfolobus-?Caldariella? group: Taxonomy on the basis of the structure of DNA-dependent RNA polymerases

The similarity of the morphology and of DNA composition, the homology of the component patterns of DNA-dependent RNA polymerases and their immunochemical crossreactivity support the conclusion that several extreme thermoacidophiles are related to each other. We name two new species of the genus Sulfolobus. The first, Sulfolobus solfataricus (DSM 1616 and DSM 1617) has the same GC content in its DNA and the same general properties as S. acidocaldarius, but differs significantly from the latter species in the molecular weights of the 11 components of its RNA polymerase and in the salt requirements of this enzyme. The second, Sulfolobus brierleyi, DSM 1651, differs from S. acidocaldarius in several respects. The cells show much less stability at neutral pH. The GC content is significantly lower. The RNA polymerase lacks two components present in the enzymes from the other species. The residual 9 components show larger size differences from the homologous subunits of the S. acidocaldarius enzyme. Like the enzyme from S. solfataricus, the polymerase from S. brierleyi yields an incomplete immunochemical crossreaction with an antibody against the RNA polymerase from S. acidocaldarius. The isolates DSM 1616 and DSM 1617 of Sulfolobus solfataricus are probably identical with or similar to the “Caldariella” strains MT 3 and MT 4, isolated by de Rosa et al. (1975). Like all other known archaebacterial RNA polymerases the enzymes from these species are insensitive to rifampicin and streptolydigin.