Summary Marine photosynthesis is largely driven by cyanobacteria, namely S ynechococcus and P rochlorococcus . Genes encoding for photosystem ( PS ) I and II reaction centre proteins are found in cyanophages and are believed to increase their fitness. Two viral PSI gene arrangements are known, psaJF→ C →A→ B → K → E → D and psaD→ C →A→ B . The shared genes between these gene cassettes and their encoded proteins are distinguish...

Summary The high genomic G+C group of Actinobacteria possesses a variety of physiological and metabolic properties, and exhibits diverse lifestyles and ecological distribution. In recent years, Actinobacteria have been found to frequently dominate samples obtained from freshwater samples. Furthermore, phylogenetic analyses have shown that 16S rRNA genes from uncultured actinobacterial freshwater samples cluster in four distinc...