Molecular Characterization of Twenty-Five Marine Cyanobacteria Isolated from Coastal Regions of Ireland

Katie Shiels; Norma Browne; Fiona Donovan; Patrick Murray; Sushanta Kumar Saha

doi:10.3390/biology8030059

Molecular Characterization of Twenty-Five Marine Cyanobacteria Isolated from Coastal Regions of Ireland

Biology (Basel). 2019 Aug 7;8(3):59. doi: 10.3390/biology8030059.

Authors

Katie Shiels¹, Norma Browne¹, Fiona Donovan¹, Patrick Murray¹, Sushanta Kumar Saha²

Affiliations

¹ Shannon Applied Biotechnology Centre, Limerick Institute of Technology, Moylish Park, Limerick V94 E8YF, Ireland.
² Shannon Applied Biotechnology Centre, Limerick Institute of Technology, Moylish Park, Limerick V94 E8YF, Ireland. Sushanta.Saha@lit.ie.

Abstract

Twenty-five marine cyanobacteria isolated from Irish coasts were characterized based on their morphological characters and 16S rRNA gene sequence analysis. In addition, superoxide dismutase (SOD) and malate dehydrogenase (MDH) isoenzyme banding patterns were used to differentiate two morphologically ambiguous isolates. In this study, six new cyanobacteria-specific primers were designed, and a 16S rRNA gene of twenty-five morphologically diverse cyanobacteria was successfully PCR amplified (1198-1396 bps). Assembled 16S rRNA sequences were used both for a basic local alignment search tool (BLAST) analysis for genus-level identification and to generate a phylogenetic tree, which yielded two major clusters: One with morphologically homogenous cyanobacteria and the other with morphologically very diverse cyanobacteria. Kamptonema okenii and Tychonema decoloratum were isolated from a single field sample of Ballybunion and were originally identified as the same 'Oscillatoria sp.' based on preliminary morphological observations. However, an alignment of 16S rRNA gene sequences and SOD and MDH isoenzyme banding pattern analyses helped in differentiating the morphologically-indistinguishable 'Oscillatoria sp.'. Finally, after a re-evaluation of their morphological characters using modern taxonomic publications, the originally identified 'Oscillatoria sp.' were re-identified as Kamptonema okenii and Tychonema decoloratum, thus supporting the polyphasic approach of cyanobacteria characterization.

Keywords: 16S rRNA sequence; isoenzyme banding pattern; malate dehydrogenase (MDH); marine cyanobacteria; molecular characterization; morphology; superoxide dismutase (SOD).