Fig. 2

Autophagic recycling of cellular material. A The autophagosomes that are diagnostic of autophagy are vesicles with double-layered membranes (arrows) and are produced by stretches of endoplasmic reticulum membranes (arrowheads). B Autophagosomes sequester cytoplasmic components including glycogen (arrowhead) and C mitochondria that are then delivered to vacuoles in gongylidium bulbs for further degradation. D–E Vacuolar expansion is mediated by fusion of autophagosomes that lose their outer membrane once they fuse with the vacuole. These single-membraned autophagic bodies are vesicles that can be seen inside the vacuole prior to their degradation (arrowhead). Images acquired by TEM (A–C), phase contrast microscopy (D) and confocal microscopy stained with dextran-Alexa Fluor 647 (E). Scale bars A–C = 500 nm, D–E = 20 μm