portrait

Description:

Portrait of Euglena sanguinea (probably synonymous with E. rubra and some other red euglenae). This species has numerous red granules containing astaxanthin among other carotenoids scattered in the cytoplasm. The granules, which may provide protection of cell structures from UV-B radiation, concentrate in a central mass under low light conditions (as seen in this image) and disperse in bright light. The cell is has a blunt point posteriorly and a broadly rounded anterior. The large stigma (mid-anterior in this image) has the same coloration as the red cytoplasmic granules. The plastids are elongate, thin and tend to parallel the fine pellicular striations. The flagellum is about body length. Cells are flexible but not highly metabolic. The nucleus is seen in the posterior 1/3 in this image. Small paramylon grains of various shapes are scattered through the cytoplasm. Swimming is slow with rotation around the long axis. Cells often appear to glide on the substrate. From stagnant fresh water with abundant rotting vegetation near Boise, Idaho. DIC optics.