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A non-culture approach was used to study the archaeal diversity in Lake Elmenteita, Kenya. Five different sampling points were selected randomly within the lake. Wet sediments and water samples were collected from each sampling point. In addition, dry mud cake was collected from three points where the lake had dried. DNA was extracted from these samples and the 16S rRNA genes were amplified using primers described to be Domain-specific for Archaea. Eleven clone libraries were constructed using PCR-amplified 16S rRNA genes. A total of 1,399 clones were picked and analysed via ARDRA. 170 ARDRA patterns were unique and the respective clones were selected for sequencing. 149 clones gave analysable sequences. BLAST analysis showed that 49 belong to the Domain Archaea while the others were either chimera or affiliated to eukaryotic taxa. Comparative sequence analysis of archaeal clones affiliated them to a wide range of genera. The order Halobacteriales was represented by members of the genera Natronococcus, Halovivax, Halobiforma, Halorubrum, and Halalkalicoccus. The highest percentage (46%) of the clones, however, belonged to uncultured members of the Domain Archaea in the order Halobacteriales. The results show that the archaeal diversity in the lake could be higher than previously reported.

The great increase in the abundance and phylogenetic diversity of Flavobacterium spp. within a few hundred meters downstream of the discharge site of the Westerhöfer Bach, a hardwater rivulet, raised the question whether adjacent soil may serve as a reservoir of bacteria not detected in discharge water. To address this question, denaturing gradient gel electrophoresis (DGGE) analyses of the V3 region of Flavobacterium 16S rRNA genes were performed on DNA from nine soil samples and five rivulet sites. The resulting patterns were tested for the significance of differences between the sampling habitats using the nonparametric analysis of similarities and multidimensional scaling procedures. Even though both habitats were sampled in two consecutive years DGGE patterns of soil and downstream water samples showed significant overlap (R = 0.614). Sequencing of 57 DGGE bands resulted in 30 different sequences, which, on the basis of BLAST analyses, were between 96% and 100% similar to published clone, DGGE, and strain sequences from a wide range of different habitats. Forty-five percent of the highly similar sequences included those of isolates from the Westerhöfer Bach, while the other sequences were more closely related to clones and cultures from other habitats, especially agricultural soil. Based on these results we suggest that the increase in flavobacterial strain diversity and abundance in the rivulet may originate from soil microflora.

Bacterial strain BF36T, isolated from the biofilm of a tufa deposit in a hard water rivulet, was characterized by a polyphasic taxonomic approach. Cells of these organisms were Gram-negative, motile, nonpigmented, rod-shaped, non-endospore-forming, and facultatively anaerobic. Cells, organized in loose consortia, were coated by a massive slime layer. Phylogenetic analyses using 16S rRNA gene sequences showed that strain BF36T was a member of the family Enterobacteriaceae, class Gammaproteobacteria, displaying a moderate degree of relationship (96.5% sequence similarity) to Sodalis glossinidius and "Sodalis pallipedes," intracellular symbionts of the tsetse fly Glossinis morsitans morsitans. Dendrograms of relationship generated by different algorithms consistently grouped isolate BF36T with Sodalis glossinidius, Pragia fontium, Budvicia aquatica, Serratia rubideae, and Brenneria spp (94.7-95.8% similarity) which also share many common metabolic properties. Differences between strain BF36T and Sodalis glossinidius DSM 13495T are seen in motility and in the pattern of substrates utilized. Membership to the family was also confirmed by a fatty acid profile consisting of major amounts of C16:0)and C16:1omega7, by the presence of isoprenoids of the ubiquinone Q8 and menaquinone MK8 types and a DNA G + C content of 54.2 mol%. The decision to classify strain BF36T into a new genus Biostraticola gen. nov. is based on its distant phylogenetic position as compared to any other representative of the family and the significant phenotypic differences to its nearest phylogenetic neighbor, Sodalis glossinidius. BF36T represents the type species, for which the name Biostraticola tofi sp. nov. is proposed. The type strain is BF36T (DSM 19580T; CIP109699T).

A single strain, designated BF49(T), was isolated from a biofilm of a tufa deposit from the Westerhöfer rivulet, Lower Saxony, Germany. The G+C content of the genomic DNA of strain BF49(T) was 69 mol% and the predominant ubiquinone was Q-8. Major fatty acids were C(16:1)omega7c/15 iso 2OH and C(16:0). Comparative 16S rRNA gene sequence analysis indicated that the isolate was placed within the genus Methylibium, class Betaproteobacteria, distantly related to the type strain Methylibium petroleiphilum LMG 22953(T) (97.4% similarity), Methylibium fulvum Gsoil 322(T )(96%), and Methylibium aquaticum IMCC1728(T )(95.7%). On the basis of phylogenetic and phenotypic distinctness we propose a novel species, Methylibium subsaxonicum sp. nov., with strain BF49(T) (DSM 19570(T), CIP 109700(T)) as the type strain.