Carbon deprivation in a strain of Euglena gracilis results in marked ultrastructural changes. Paramylum granules disappear, massive vacuolization of the endoplasmic reticulum occurs, and whole areas of cytoplasm are segregated and sacrificed with the production of lysosomes. Nuclear changes are minimal and mitochondria appear normal unless starvation is prolonged. In spite of the severity of the changes, replenishment of the carbon source after 8 days of starvation results in complete reversal to a normal morphology, except perhaps for the persistence of lysosomal-like particles. Bizarre mitochondria are associated with the early stages of refeeding, but soon revert to normal. Paramylum granules are secreted directly by the membranes of the cisternae of the ER as a final stage of the recovery process.
ASJC Scopus subject areas
- Cell Biology