Absorptio Spectrum<i>in vivo</i>of the Blue Pigment ‘Marennine’ of the Pennate Diatom<i>Navicula ostrearia</i>Bory

Abstract

Biological and environmental conditions affect the intracellular contents of the diatom Navicula ostrearia Bory. Thus this alga has the peculiarity of synthesizing marennine, a blue-green pigment of an undefined chemical nature. The present study deals with a cytophotometric method permitting identification of the pigment in vivo, by its characteristic extinction spectrum: there is a sharp extinction peak at 623 nm. Culture medium coloured blue-green by marennine also absorbs red light but there is no peak at 623 nm, only a broad maximum at about 663 nm, because the aqueous solution is certainly a mixture of the blue pigment and other water-soluble algal products. Nevertheless, it seems possible that marennine may be a similar biliprotein pigment whose precise molecular structure needs to be determined.