Abstract
H. J. Busse, P. Kampfer, ERB. Moore, J. Nuutinen, I. V. Tsitko, EBM. Denner, L. Vauterin, M. Valens, R. Rossello-Mora and M. S. Salkinoja-Salonen
Institut fur Mikrobiologie und Genetik, Universitat Wien, A-1030 Wien, Austria
Four aerobic, Gram-negative bacterial strains isolated from kaolin slurry used in the production of paper were subjected to a polyphasic analysis and characterization to determine their taxonomic position. Analysis of the 16S rDNA sequences of the four strains revealed that they represent a new lineage within the gamma-Proteobacteria, related to the genera Xanthomonas, Pseudoxanthomonas, Stenotrophomonas, Luteimonas, Xylella and Rhodanobacter. Analysis of the quinone system, the polyamines, the fatty acids and the polar lipids revealed a combination of characteristics that is unique and not described for the phylogenetic relatives. The four strains contain a ubiquinone Q-8, spermidine as the major polyamine, diphosphatidylglycerol, phosphatidylglycerol and phosphatidylethanolamine as the predominant polar lipids, and a fatty acid profile with predominantly iso-branched fatty acids. The G+C content of the genomic DNA was determined to be within the narrow range 67.1--68.7 mol%. Determination of DNA relatedness, as well as riboprint band patterns and amplified fragment length polymorphism profiles, clearly demonstrated that the four strains are members of a single species. Antibiotic-susceptibility patterns were identical for the four strains. Although showing a high degree of similarites in physiological and biochemical patterns, each of the four strains could be distinguished from the others on the basis of a few biochemical characteristics. On the basis of the estimates of phylogenetic relationships derived from the 16S rDNA sequence analyses, the observed chemotaxonomic characteristics and other phenotypic traits, a new genus, Thermomonas gen. nov., and species, Thermomonas haemolytica sp. nov., are proposed for the strains A50-7-3(T) (=DSM 13605(T)=LMG 19653(T)), B 50-7-1 (=DSM 13598=LMG 19655), D50-7-1 (=DSM 13610=LMG 19656) and B50-8-1 (=DSM 13599=LMG 19654), with strain A50-7-3(T) as the type strain.