METABOLIC IMAGING OF FRAGILARIOPSIS CYLINDRUS IN POLAR NIGHT CONDITIONS USING FULL FIELD OPTICAL TRANSMISSION TOMOGRAPHY (FFOTT)

FFOTT is a non-invasive non-destructive method of imaging that was found promising for a broad range of applications. We applied FFOTT to compare intracellular dynamic signals, a proxy for cellular metabolic activity. We investigated the metabolic changes associated with the transition from and towards polar night in the polar diatom Fragilariopsis cylindrus, grown under continuous illumination or kept in darkness for six weeks. Our results revealed a tenfold signal decrease in darkness and a rapid signal recovery upon re-illumination. Photosynthetic performance was assessed in parallel. Biovolume determinations allowed the computation of the metabolic rates of F. cylindrus grown under both light and dark conditions, which were compared to the optical signal variations.