Structure of the 16 S ribosomal RNA of the thermophilic cyanobacterium Chlorogloeopsis HTF (‘Mastigocladus laminosus HTF’) strain PCC75 18, and phylogenetic analysis

The thermophilic cyanobacterial strain, PCC7518, originally identified as ‘Mu~tigocludus hminosus HTF’ does not show branchings or heterocysts.
The absence of branchings supports the later assignment to the genus Chlorogloeopsu. The absence of heterocysts may be the result of a mutation
because heterocysts were observed in the original isolate. Alternatively, contamination may have happened. To solve this problem, the 16 S rRNA
sequence was determined and used to infer a secondary structure model and build distance trees. The trees showed that strain PCC7518 belongs
to the cluster of heterocystous species and has most probably lost the abihty to produce heterocysts by mutation. It is only distantly related to
Chlorogloeopsis fritschii PCC67 18.