Nitrogen and Sulfur Starvation of the Cyanobacterium Synechococcus 6301 An Ultrastructural, Morphometrical, and Biochemical Comparison

Abstract

The effects of nitrogen and sulfur limitation on various cellular parameters of the cyanobac-terium Synechococcus 6301 were studied by electron microscopy, morphometry and biochemical methods. Nitrate and sulfate starvation for 70 h results in a massive glycogen accumulation in parallel to a loss of soluble protein and chlorophyll. Phycobilisomes disappear prior to the degradation of photosynthetic membranes. For sulfate-starved cells a formation of “storage granules” (poly-P-hydroxy-butyric acid) is typical which amount up to 10% of the cell volume. The composition of polar lipids is simple: Equal parts of C 16:0 and C 16:1 are present under all nutritional conditions; their amount is directly correlated with the total cellular membrane area as determined by morphometry. Nitrate starved cells regenerate almost completely in structure and composition within 9 h after nitrate supplementation. Regeneration of sulfate starved cells is retarded; in spite of significant synthesis of phycocyanin within 9 h the cells still exhibit marked signs of starvation. © 1986, Verlag der Zeitschrift für Naturforschung