Divergent members of the bacterial division Verrucomicrobiales in a temperate freshwater lake

Bacterial diversity in the water column of a freshwater lake in the Netherlands was investigated by analysis of 16S rRNA gene sequences recovered through PCR amplification from total community DNA. Among 23 unique cloned sequences, two appeared to belong to the recently described bacterial division Verrucomicrobiales. One of the two sequences was most similar to a group of environmental clones that form a distinct lineage within the division. The other sequence was divergent (less than 85% similarity) from all 16S rRNA gene sequences, both from cultivated species and from environmental clones, known in this division to date. Analysis by denaturing gradient gel electrophoresis (DGGE) and sequencing of DNA recovered through excision from the DGGE gel showed that the two sequence types were present in the lake throughout the year