Archaeal community structures in the solfataric acidic hot springs with different temperatures and elemental compositions.

Archaeal 16S rRNA gene compositions and environmental factors of four distinct solfataric acidic hot springs in Kirishima, Japan were compared. The four ponds were selected by differences of temperature and total dissolved elemental concentration as follows: (1) Pond-A: 93°C and 1679 mg L(-1), (2) Pond-B: 66°C and 2248 mg L(-1), (3) Pond-C: 88°C and 198 mg L(-1), and (4) Pond-D: 67°C and 340 mg L(-1). In total, 431 clones of 16S rRNA gene were classified into 26 phylotypes. In Pond-B, the archaeal diversity was the highest among the four, and the members of the order Sulfolobales were dominant. The Pond-D also showed relatively high diversity, and the most frequent group was uncultured thermoacidic spring clone group. In contrast to Pond-B and Pond-D, much less diverse archaeal clones were detected in Pond-A and Pond-C showing higher temperatures. However, dominant groups in these ponds were also different from each other. The members of the order Sulfolobales shared 89% of total clones in Pond-A, and the uncultured crenarchaeal groups shared 99% of total Pond-C clones. Therefore, species compositions and biodiversity were clearly different among the ponds showing different temperatures and dissolved elemental concentrations.

Archaeal diversity in two thermophilic chalcopyrite bioleaching reactors.

This study used a culture-independent molecular approach to investigate the archaeal community composition of thermophilic bioleaching reactors. Two culture samples, MTC-A and MTC-B, grown with different concentrations of chalcopyrite (CuFeS2), a copper sulfidic ore, at a temperature of 78 degrees C and pH 1.6 were studied. Phylogenetic analysis of the 16S rRNA genes revealed that both cultures consisted of Archaea belonging to the Sulfolobales. The 16S rRNA gene clone library of MTC-A grown with 4% (w/v) chalcopyrite was dominated by a unique phylotype related to Sulfolobus shibatae (69% of total clones). The remaining clones were affiliated with Stygiolobus azoricus (11%), Metallosphaera sp. J1 (8%), Acidianus infernus (2%), and a novel phylotype related to Sulfurisphaera ohwakuensis (10%). In contrast, the clones from MTC-B grown with 12% (w/v) chalcopyrite did not appear to contain Sulfolobus shibatae-like organisms. Instead the bioleaching consortium was dominated by clones related to Sulfurisphaera ohwakuensis (73.9% of total clones). The remaining microorganisms detected were similar to those found in MTC-A.

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.

The Judicial Commission of the International Committee on Systematics of Prokaryotes has corrected the nomenclatural types of 12 orders: Acholeplasmatales, Halanaerobiales, Halobacteriales, Methanobacteriales, Methanococcales, Methanomicrobiales, Planctomycetales, Prochlorales, Sulfolobales, Thermococcales, Thermoproteales and Verrucomicrobiales.

[Study on reclassification of extremely thermoacidophilic archaea strain S5].

The further study on thermoacidophilic archaea strain S5, with has been identified as Sulfosphaerellus thermoacidophilum gen.nov.,sp.nov, has shown it was able to grow facultatively aerobically by means of two sulfur-metabolizing modes of chemolithotrophy which is the characteristic of Acidianus. And the 16SrRNA gene of strain S5 was amplified, cloned and sequenced, a phylogenetic tree was constructed on the 16SrRNA gene sequences. The tree clearly indicated that strain S5 formed the same lineage with Acidianus brierleyi. Thus strain S5 should be the member of Acidianus. However, there are only 44%, 22% and 23% genomic DNA similarity between S5 and A. brierleyi. A. infernus and A. ambivalens, respectively. And the G + C content of S5 DNA is 38%, which is 5% ~ 7% higher than the reported G + C contents of the other Acidianus species (31% or 32.7%) . In addition, strain S5 is a strictly chemolithoautotrophs, which is obviously different from facultative chemolithotrophs of A brierleyi. Based on the observed differences, strain S5 represents a new species within the genus Acidianus. A new species name, Acidianus tengchongenses, was proposed for it. The type strain is designated S5.

Sulfurisphaera ohwakuensis gen. nov., sp. nov., a novel extremely thermophilic acidophile of the order Sulfolobales.

Three spherical thermoacidophilic archaea (strains TA-1T, TA-13, TA-14) were obtained from acidic hot springs located in Ohwaku Valley, Hakone, Japan. All the isolates are facultatively anaerobic, and grew optimally at around 85 degrees C, pH 2.0. Isolate TA-1T was characterized further. The G + C content of DNA from TA-1T is 33 mol%. Although these properties resemble those of the genus Acidianus, the sequence of the 16S rRNA gene from strain TA-1T was more similar to that of species of Stygiolobus than of Acidianus. DNA-DNA hybridization experiments also indicated that strain TA-1T is clearly distinguished phylogenetically from the members of Acidianus, Sulfolobus and Metallosphaera. On the basis of the distinct physiological and molecular properties, we describe the new strains as members of the new genus Sulfurisphaera. The type species of the genus is Sulfurisphaera ohwakuensis, and the type strain of the species is TA-1T (= IFO 15161T).

Using protein synthesis inhibitors to establish the phylogenetic relationships of the Sulfolobales order.

The sensitivity of the cell-free protein synthesis systems from Acidanus brierleyi, Acidianus infernus, and Metallosphaera sedula, members of the archaeal order Sulfolobales, to 40 antibiotics with different specificities has been studied. The sensitivity patterns were compared to those of Sulfolobus solfataricus and other archaeal, bacterial, and eukaryotic systems. The comparative analysis shows that ribosomes from the sulfolobales are the most refractory to inhibitors of protein synthesis described so far. The sensitivity results have been used to ascertain in phylogenetic relationships among the members of the order Sulfolobales. The evolutionary significance of these results are analyzed in the context of the phylogenetic position of this group of extreme thermophilic microorganisms.