Chlorophyll catabolites in conditioned media of green microalga Desmodesmus subspicatus

Abstract

Although the appearance of coloured chlorophyll degradation products of higher plants is well known, knowledge about such compounds produced and released particularly by planktonic algae is still limited. Colourless conditioned media (CM) obtained from autotrophic cultures of unicellular green alga Desmosdemus subspicatus turn red after acidification. The accumulation of red pigments in the medium and the growth rate of algae were inversely correlated. The red, crude solution isolated from CM by dialysis and ion exchange chromatography, and next purified by means of high-performance liquid chromatography, appeared to be a mixture of three compounds with characteristic UV/VIS absorption maxima near 330 and 505 nm. Electrospray ionization (ESI) mass spectrometry analysis revealed that the molecular mass of the most polar and most abundant compound was 637 Da and molecular masses of two other ones were 641 and 607 Da. Addition of 15 N isotope to the culture medium and subsequent mass spectrometry measurements revealed the occurrence of four nitrogen atoms per each molecule. The data suggest that red pigments isolated from algal-conditioned media are chlorophyll degradation compounds, the production of which depends on light intensity, and are released mainly during the stationary phase of growth.

Exploiting microalgal competition ability to acquire nitrogen and light

“…2011; Grabski et al . 2016). Further, the evaluation of the effect of cell size on the nitrogen assimilation suggested that large cells show greater ability to store nutrients (Stolte & Riegman 1997; Litchman et al .…”

“…The activity of a plasma membrane cytochrome oxidase generated a H + gradient which serves as a pump to extrude the extra salt out of the cells under high Na + environment. Rai and Gaur (2001) Alkaline Hamm and Smetacek (2007) Size adaptation Phytoplankton As cell size increase, competitive ability decreases for nitrogen and phosphorus Edwards et al (2011) or chlorophyll degradation products released by both Nannochloropsis and Dunaliella (Grabski et al 2016;Misra et al 2016). This observation raises the hypothesis that the exudation might result from the drastic metabolic reorganization occurring in the cell wall in order to adapt to stressful conditions (Jinkerson et al 2011;Grabski et al 2016).…”

“…Rai and Gaur (2001) Alkaline Hamm and Smetacek (2007) Size adaptation Phytoplankton As cell size increase, competitive ability decreases for nitrogen and phosphorus Edwards et al (2011) or chlorophyll degradation products released by both Nannochloropsis and Dunaliella (Grabski et al 2016;Misra et al 2016). This observation raises the hypothesis that the exudation might result from the drastic metabolic reorganization occurring in the cell wall in order to adapt to stressful conditions (Jinkerson et al 2011;Grabski et al 2016). Further, the evaluation of the effect of cell size on the nitrogen assimilation suggested that large cells show greater ability to store nutrients (Stolte & Riegman 1997;Litchman et al 2007;Malerba et al 2016).…”

Chlorophyll Oxidative Metabolism During the Phototrophic and Heterotrophic Growth of Scenedesmus obliquus

“…A very close relationship has been always suggested between the chlorophyll catabolic pathway in chlorophytes and in higher plants [26], which is not unlikely assuming the phylogenetic relationship between both taxonomic groups. In fact, open chlorophyll catabolites with similar structures to those of phyllobilins have been identified in Chlorella [26,27] or in Desmodesmus subpicatus [28]. In parallel, chlorophylls are subjected to an oxidative metabolism [29,30].…”

“…In fact, open chlorophyll catabolites with similar structures to those of phyllobilins have been identified in Chlorella [26,27] or in Desmodesmus subpicatus [28]. In parallel, chlorophylls are subjected to an oxidative metabolism [29,30].…”