The content and composition of phycobilisome pigments in cells of ancient viable cyanobacteria from Arctic permafrost

Comparative analysis of the absorption spectra of cells of four ancient cya nobacteria (Oscillatoria sp., Phormidium sp., Nostoc sp., and Anabaena sp.) from frozen lake sediments of the Holocene period revealed the presence of phycobiliproteins and carotenoids in their cells. The phycobilisomes were isolated; their absorption spectra and the second derivatives of the latter were recorded. The following phycobiliproteins were identified: C-phycoery thrin, phycocyanin, allophycocyanin, and allophycocyanin B. Cyanobacteria o f different orders (Oscillatoriales and Nostocales) differed considerably i n the contents of phycoerythrin and phycocyanin (relative to the chlorophyl l a content). Fluorescence spectra of intact and heat-denatured phycobiliso mes demonstrated energy migration between peripherally located phycobilipro teins and allophycocyanin B, the terminal acceptor of the excitation energy . No significant differences between the spectral characteristics of phycob ilisomes of ancient and modern cyanobacteria were revealed, which suggests high similarity of their structural and functional properties.