An Unusual Phycocyanobilin-containing Phycoerythrin of Several Bluish-colored, Acrochaetioid, Freshwater Red Algal Species

Résumé du livre

The reproductive biology and phycobiliproteins of four different culture isolates of the freshwater algae Audouinella and 'Chantransia' were investigated.'Chantransia' sp. (3585/UTEX 2623) and Audouinella macrospora (Wood) Sheath et Burkholder (3394,3395) from California and Minnesota reproduced only by monospores. However, A. macrospora (3603/Necchi 1) reproduced by monosporangia that formed successive generations of the Audouinella phase, and Batrachospermum shoots developed from the basal and erect systems. The major light-harvesting phycobiliprotein in all of these isolates was a phycocyanobilin-containing phycoerythrin not previously detected in red algae or cyanobacteria. As in the commonly found R- and B-phycoerythrins, Audouinella phycoerythrin had a native molecular mass of ~ 240,000 and was made up of Alfa, Beta, and Gamma subunits. Audouinella phycoerythrin carried two phycoerythrobilins on the Alfa subunit; one phycourobilin, one phycoerythrobilin, and one phycocyanobilin on the Beta subunit; and one phycourobilin and two phycoerythrobilins on the Gamma subunit. With excitation at 495, 563, or 603 nm, the fluorescence emission peak of Audouinella phycoerythrin was at 626 nm, showing that phycocyanobilin was the terminal energy acceptor.