In situ analysis of sulfate-reducing bacteria related to Desulfocapsa thiozymogenes in the chemocline of meromictic Lake Cadagno (Switzerland)

Comparative sequence analysis of a 16S rRNA gene clone library from the che mocline of the meromictic Lake Cadagno (Switzerland) retrieved two clusters of sequences resembling sulfate-reducing bacteria within the family Desulf ovibrionaceae. In situ hybridization showed that, similar to sulfate-reduci ng bacteria of the family Desulfobacteriaceae, bacteria of one cluster with similarity values to the closest cultured relatives of between 92.6 and 93 .1% resembled free cells or cells loosely attached to other cells or debris . Bacteria of the second cluster closely related to Desulfocapsa thiozymoge nes DSM7269 with similarity values between 97.9 and 98.4% were generally as sociated with aggregates of different small celled phototrophic sulfur bact eria, suggesting a potential interaction between the two groups of bacteria .