UV protecting pigment of the terrestrial cyanobacterium Tolypothrix byssoidea

Abstract

Summary Absorption spectra of methanolic extracts of the terrestrial cyanobacterium, Tolypothrix byssoidea , isolated from rock surfaces exposed to bright sunlight and grown under fluorescent light showed prominent absorption at 260, 330 and 384 nm in the UV range of the spectrum. The organism was able to survive and retain the absorption peaks at 260 and 384 nm even after 24 h of UV-C irradiation. In contrast, a Tolypothrix sp. isolated from rice fields could not survive 30 min of similar UV irradiation and did not show absorption at 384 nm. The isolated sheath fraction of T. byssoidea absorbed strongly in the near-UV-blue region of the spectrum. The pigment absorbing at 384 nm reflects an adaptive strategy of terrestrial cyanobacteria to cope with damaging short-wavelength solar radiation.