Pyrinomonas methylaliphatogenes gen. nov., sp. nov., a novel group 4 thermophilic member of the phylum Acidobacteria from geothermal soils.

An aerobic, thermophilic, moderately acidophilic non-spore-forming bacterium, strain K22(T), was isolated from geothermally heated soil at Mount Ngauruhoe, New Zealand. On the basis of 16S rRNA gene sequence similarity, K22(T) was shown to belong to subdivision 4 of the phylum Acidobacteria and to be most closely related to 'Candidatus Chloracidobacterium thermophilum' (86 %) and Blastocatella fastidiosa (86 %). Cells stained Gram-negative and were catalase and oxidase-positive. The major fatty acids detected were iso-C15 : 0, iso-C17 : 0, iso-C19 : 0 and iso-C21 : 0 when standard lipid extraction protocols were employed. Analysis of the total cell lipid acid hydrolysate also detected membrane-spanning and ether lipids, which made up approximately 40 % of the total membrane composition. These lipids included dicarboxylic (iso-diabolic) acid and the glyceryl ether of alkyl analogues of iso-C15 : 0 and iso-diabolic acid. The G+C content of the genomic DNA was 59.6 mol% and the primary respiratory quinone was MK-8. Strain K22(T) grew at 50-69 °C with an optimum temperature of 65 °C and at pH 4.1-7.8 with an optimum growth pH of 6.5. NaCl tolerance was up to 1 % (w/v). Cells displayed a chemoheterotrophic and obligately aerobic metabolism. Cells grew on nutrient broth, alginate, arabinose, Casamino acids, glucose, lactate, formate, mannose, sodium alginate, peptone, sucrose, tryptone, xanthan, xylan, xylose and yeast extract. Nitrogen sources included nitrate, ammonium, urea, yeast extract and Casamino acids, but not dinitrogen gas. The distinct phylogenetic position and the phenotypic characteristics separate strain K22(T) from all other members of the class Acidobacteria and indicate that it represents a novel species and genus, for which the name Pyrinomonas methylaliphatogenes gen. nov., sp. nov. is proposed. The type strain of the type species is K22(T) ( = DSM 25857(T) = ICMP 18710(T)).

Phylogenetic delineation of the novel phylum Armatimonadetes (former candidate division OP10) and definition of two novel candidate divisions.

Small-subunit (SSU) rRNA gene sequences associated with the phylum Armatimonadetes were analyzed using multiple phylogenetic methods, clarifying both the phylum boundary and the affiliation of previously ambiguous groupings. Here we define the Armatimonadetes as 10 class-level groups and reclassify two previously associated groups as candidate divisions WS1 and FBP.

Fatty Acids of Chthonomonas calidirosea, of a novel class Chthonomonadetes from a recently described phylum Armatimonadetes.

A Gram-negative, aerobic, pink-pigmented, rod-shaped bacterium Chthonomonas calidirosea (strain T49(T)) with an optimal temperature for growth of 68 °C, isolated from soil samples from Hell's Gate in the Tikitere geothermal system (New Zealand), was the first cultivated bacterium of the novel phylum Armatimonadetes (formerly candidate division OP10). The lipid composition of C. calidirosea presents a number of unusual features both in the fatty acids and polar lipids. This contribution reports on the fatty acid profile of C. calidirosea. Transmethylation of bacterial biomass yielded fatty acid methyl esters and hydrocarbons, including squalene, partially hydrogenated squalenes, and diploptene. The only type of unsaturation found in C. calidirosea fatty acids was cis-Δ5, as revealed by GCMS of dimethyl disulfide (DMDS) adducts, and the lack of trans-unsaturation absorbance at 960-980 cm(-1) in the IR spectrum of fatty acids methyl esters. An unidentified component X with ECL 16.86 (BP1) and ECL 17.27 (BP20) was also observed, with molecular ion at m/z 282 ("17:1"). X did not form DMDS adducts, nor was affected by mild hydrogenation conditions, indicating the likely presence of a ring rather than unsaturation. The presence of a cyclopropane ring with cis-stereochemistry was confirmed by the (1)H-NMR spectrum. Hydrogenation of X in acetic acid resulted in formation of straight chain 17:0, 5-methyl- and 6-methyl-16:0 fatty acid methyl esters, thus confirming the structure of a novel 5,6-methylene hexadecanoic acid. The major fatty acids of a solid media-grown C. calidirosea were as follows (in weight % of total fatty acids): 16:0 (25.8), i17:0 (19.3), ai17:0 (13.5), 16:1∆5 (8.8), i17:1∆5 (6.8), 5,6-methylene 16:0 (5.2), i16:0 (4.4), 18:0 (3.6), 18:1∆5 (3.2).