Stress Responsive Gene for UV-A in Marine Cyanobacterium Oscillatoria sp

Abstract

Recently, we have isolated a new type of UV-A resistant marine cyanobacteria Oscillatoria sp. which grow under UV A irradiation and produce bioputerin as an UV-A absorbing pigment (Matsunaga et al., 1993). This pigment was related to the pterine pigments found in butterfly wings UV-A sensitive isolates did not produce significant levels of this chromophore. UV-A radiation was very effective in eliciting biopterin glucoside synthesis, in which intracellular level of biopterin glucoside was correlated with the intensity of UV-A. These results suggested that biopterin glucoside may protect the cyanobacterium from adverse effects of UV-A irradiation. Furthermore, the effect of an UV-A light intensity on cell growth, biopterin glucoside production and photosynthetic activity was investigated (Wachi et al., 1995). The marine Oscillatoria sp. NKPB 091600 could grow at UV-A intensities of up to 800 µW·cm ⁻² and could grow at 300 µW·cm ⁻² as well as in the absence of UV-A irradiation. The photosynthetic activity of pre-cultured cells with UV-A was protected well from UV-A induced inhibition. It was demonstrated that a rapid increase in bioterin glucoside content was observed after 10 hr under UV-A radiation.