Reclassification of thermophylic methane-oxidizing bacteria with the use of sequence-analysis of 16S rRNA genes

• Published in: Mikrobiolohichnyĭ zhurnal (Kiev, Ukraine : 1993) Vol. 68; no. 1; p. 3
• Main Authors: Romanovskaia, V A, Rokitko, P V, Shilin, S O, Malashenko, Iu R
• Format: Journal Article
• Language: Russian
• Published: Ukraine 01-01-2006
• Subjects: Genes, Bacterial; Methanobacteriaceae - classification; Methanobacteriaceae - genetics; Phylogeny; RNA, Bacterial - genetics; RNA, Ribosomal, 16S - genetics; Sequence Analysis, RNA; Species Specificity
• ISSN: 1028-0987

The authors have performed sequence-analysis of 16S rRNA genes of thermophylic methane-oxidizing bacteria UCM B-3026, UCM B-3032, UCM B-3109, UCM B-3014 which were isolated from sludge pond of different regions in Ukraine and deposited at Ukrainian Collection of Microorganisms (UCM) as Methylococcus thermophilus and "M. gracilis". A comparative analysis of 16S rRNA gene sequences of the studied bacteria with those sequences of various strains of bacteria in the GenBank databases has shown that the level of similarity of the strains UCM B-3026, UCM B-3032, UCM B-3109 with Methylocaldum szegediense was 98.0-98.7%, strain UCM B-3014 with Methylocaldum gracile--99.1%, that allows to relate them to these species. As to other species of the genus Methylocaldum, these strains had a lower level of similarity (94.8-97.2 %) and with Methylococcus thermophilus ACM 3585T (= IMV-B-3037T = UCM B-3037T)--less than 90%. Thus, the strains UCM B-3026, UCM B-3032, UCM-3109 were reclassified as Methylocaldum szegediense, strain UCM B-3014--as Methylocaldum gracile. When constructing phylogenetic tree based on the comparison of 16S rRNA genes with the use of various algorithms realized in the packages of programs Tree View (version 1.5.2) and ClastalX (version 1.81) certain clusters have formed genera Methylocaldum, Methylococcus and Methylomonas. Genera Methylobacter and Methylomicrobium have formed three clusters, one of the clusters contained two species of Methylobacter and two species of Methylomicrobium. Apparently, the taxonomy of genera Methylobacter and Methylomicrobium is to be specified.