Isolation and characterization of the cytoplasmic membranes from the blue green alga cyanobacterium anacystis nidulans
Omata, T.; Murata, N.
Plant and Cell Physiology 24(6): 1101-1112
Cells of the blue-green alga (cyanobacterium) A. nidulans were disintegrated, and their thylakoid membranes and cytoplasmic membranes were isolated by flotation 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 .beta.-carotene and chlorophyll a as 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 chlorophyll a at 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 nm.