New genus of Maltese microorganisms

A new genus and species of cyanobacteria, the most primitive photosynthetic microorganisms, has just been described and published in the European Journal of Phycology, one of the leading journals on the subject.

The paper is entitled ‘The Subaerophytic Cyanobacterium Oculatella subterranea (Oscillatoriales, Cyanophyceae) gen. et sp. nov: a cytomorphological and molecular description and is co-authored by Gabrielle Zammit, Daniela Billi and Patrizia Albertano.

These microorganisms are made up of very thin filaments of purple-red cells, about 2 μm in diameter. Each filament possesses a photosensitive orange spot at the tip, which contains a rhodopsin-like pigment. The purple-red colouration is due to the pigment phycoerythrin, which enables the cyanobacteria to carry out photosynthesis under low-light intensities.

Another feature, which confers an advantage to these microorganisms to survive in such an extreme environment, is the photosensitive tip on each filament, which permits them to glide towards the light. The figures show the purple-red colouration of the cyanobacteria isolated in culture and the autofluorescence of the trichomes under confocal laser scanning microscopy.

The seven strains included in this genus were isolated from phototrophic biofilms growing on wall paintings in ancient hypogea situated around Malta and Italy. The DNA of all strains was found to be very closely related and only distantly related to other established cyanobacterial groups. These strains have only been isolated from subterranean environments so far, and considering also this unique habitat and their particular ecology, the new genus and species Oculatella subterranea were proposed. The genus name Oculatella means “provided with a small eye”. The genus Oculatella is of common distribution in local hypogea.

Dr Zammit, postdoctoral researcher and the main author of this scientific paper, has recently joined the Laboratory of Molecular Genetics at the University of Malta as part of Professor Alex Felice’s team. The description of other new genera and species of cyanobacteria and microalgae is currently under way both from the genetic and metabolic aspect.