Abstract:
PCR-based denaturing gradient gel electrophoresis (DGGE) analysis of 16S rRNA
gene fragments was used to identify the cyanobacterial phylotypes in sediments
and plankton of saline–alkaline and freshwater lakes of Kenya. The detection of the
aminotransferase domain located on modules mcyE and ndaF using specific
molecular markers confirmed the presence of potential toxin-producing cyanobacteria.
The eight nucleotide sequences obtained from DGGE bands were placed
in three divergent cyanobacterial clusters. Five nucleotide sequences were close to
members of the genera Anabaenopsis and Umezakia (Nostocales), two sequences fell
in the cluster with Arthrospira sp. (Oscillatoriales) and one sequence was related to
Chroococcidiopsis sp. (Pleurocapsales). The presence of the latter taxon was
demonstrated de novo in the investigated lakes. All nine attained nucleotide
sequences of the aminotransferase region belonged to the mcyE module. Five
sequences of the aminotransferase domain were included in the cluster having the
nucleotide sequence of Anabaena sp. but showed a separate lineage. Other four
aminotransferases were placed in the cluster represented by nucleotide sequence of
Microcystis aeruginosa. To our knowledge, this is the first report on molecular
detection of cyanobacterial phylotypes in sediments of African lakes and aminotransferase
domains for cyanotoxin production from sediment samples in general.
