Isolation and Characterization of the Cytoplasmic Membranes from the Blue-Green Alga (Cyanobacterium)Anacystis nidulans

摘要

Cells of the blue-green alga (cyanobacterium)Anacyslis nidulanswere disintegrated, and their thylakoid membranes and cytoplasmic membranes were isolated by floatation centrifugation on a sucrose density gradient. Electron micrographs revealed that the cytoplasmic membranes formed single closed vesicles having diameters of 200–400 nm. These membranes contained xanthophylls as the major constituent pigments and rβ-carotene and chlorophyll a as very minor ones. The major peaks in their absorption spectra were due to carotenoids at 435, 455 and 487 nm, with a minor one due to chlorophyllaat 673 nm. These findings are consistent with the yellow color of the cytoplasmic membranes. The absorption spectrum of the membranes in the carotenoid region was markedly affected by temperature: with a decrease in temperature, the peaks at 455 and 487 nm diminished and a new peak appeared at 390