Acclimation of a mesophilic cyanobacterium, Synechocystis sp. PCC 6803 to the growth temperature

摘要

Photosynthetic organisms usually experience large changes in environmental factors, such as temperature [Falk et al. 1996], light intensity or light quality [Pearcy et al. 1996]. Temperature is one of the most important factors, which control the enzymatic reaction including photosynthesis. Murata and his co-workers have investigated the acclimation mechanisms of mesophilic cyanobacteria to environmental temperatures and reported relationship between desaturation of fatty acid and acclimation to the temperature [e.g. Los etal. 1997]. They showed that turn over of the damaged D1 protein of photosystem II (PS II) become inhibited in the chilly temperatures when desaturation enzymes were destroyed [Kanervo et al. 1997]. However, the acclimation process to high temperature incyanobacteria is not well understood. We have reported the responses of photosynthetic systems in a thermophilic cyanobacterium to high temperature stress [Inoue et al. 2000]. In that report, it was shown that the PS II was most sensitive to high temperatures. In a more recent paper, we showed that the mesophilic cyanobacterium Synechocystis sp. PCC 6803 regulated both the initial photochemical activity of PS II and the oxygen-evolving activity so as to acclimate to high temperatures [Inoue et al. 2001]. It seems that this cyanobacterium acclimates to the surrounding temperature to maintain a certain rate of the PS II activity irrespective of the growth temperature.