Transmission electron micrographs of intermediate <i>H. pluvialis</i> cells.

<p><b>A</b>. General ultrastructure. <b>B</b>. High-magnification view of astaxanthin oil droplets. <b>C</b>. Partial degradation of thylakoids (arrow). <b>D</b>. High-magnification view of thylakoid degradation (arrows). C, chloroplast; CW, cell wall; N, nucleus; OD; oil droplet; P, pyrenoid; SC, starch capsule; SG, starch grain. Scale bars in A and B–D: 5 µm and 1 µm, respectively.</p>