UV absorbing pigments in terrestrial cyanobacteria from various archaeological monuments of India

摘要

Absorption of the methanolic extracts (90 percent v/v) of 17 different cyanobacterial isolates from the exposed surfaces of several archaeologically important monuments of India was studied to findout the presence of UV sunscreen pigments in these organisms. All these organisms belonging to the genera Nostoc, Calothrix, Tolypothrix and Fischerella absorbed in the UV region of the spectrum in the wavelength range of 305-384 nm due to presence of mycosporine amino acid like substances (MAAs). Of these, eight species which possessed coloured sheath layers showed prominent absorption at 384 nm in the UV-A region of the spectrum. Presence of UV absorbing pigments in these terrestrial cyanobacteria is an adaptive strategy for their survival under solar UV radiation.