A new simple method for quantification and locating P and N reserves in microalgal cells based on energy-filtered transmission electron microscopy (EFTEM) elemental maps
Abstract:We established a new simple approach to study phosphorus (P) and nitrogen (N) reserves at subcellular level potentially applicable to various types of cells capable of accumulating P- and/or N-rich inclusions. Here, we report on using this approach for locating and assessing the abundance of the P and N reserves in microalgal and cyanobacterial cells. The approach includes separation of the signal from P- or N-rich structures from noise on the energy-filtered transmission electron microscopy (EFTEM) P- or N-ma… Show more
“…The reserve structures were represented by regularly distributed moderately ample α-granules (glycogen), β-granules (lipid droplets), and polyhydroxybutyrate (PHB) granules. On the periphery of the PHB granules close to the nucleoid, and in the interthylakoid space, the electron-dense granules were located, identified by their EDX spectra as P-containing inclusions (PolyP) [ 48 ]. The granules of cyanophycin were small (0.015 ± 0.001 μm 2 on an average) and encountered on less than 60% of the studied cell sections ( Figure 6 ).…”
Section: Resultsmentioning
confidence: 99%
“…PCC 7118 in transit from P starvation to ample P conditions. We also complemented the traditional transmission electron microscopy (TEM) with analytical TEM, providing reliable information on the subcellular distribution of P-rich inclusions [ 48 ], including polyphosphate formed after the refeeding of P-starving cells [ 58 ]. We leveraged these data to search for specific acclimations to ample P conditions.…”