Concerning the role of mitochondria in cryptobiosis

The metabolic characteristics of the mitochondria of Agaricus bisporus are altered in the zygote by specific inhibitors that permit them to retain structural integrity in the dormant spore and enable them to initiate energy production, with apparent protein synthesis and replication during the initial phase of germination. The insensitivity of the earliest events of germination to selective cytoplasmic and nuclear inhibitors characterizes this as a transient period of unusual mitochondrial autonomy. To define the intrinsic metabolic potentials of the organelle and its role in cryptobiosis, mitochondria were fractionated aseptically from presporulating zygotes and were placed in dialysis chambers surrounded by nutrient media at 15 C. For periods through 48 hours, the isolated mitochondria manifested the capacity to incorporate labeled amino acids linearly into proteins and retained stable electrophoretic protein profiles for more than 5 days. They maintained fine structural integrity for at least 10 days, some developed septational membranes, and they increased numerically. These metabolic activities were dependent upon a nutrient substrate.