Aging of plasmodial heterokaryons in Didymium iridis

Summary

Isogenic diploid plasmodia of different ages were produced by crossing clonal gamete populations of the myxomycete Didymium iridis. These plasmodia were then used to produce “age” heterokaryons to study the timing of death in comparison to the senescence of the two original homokaryons. A majority of the age heterokaryons died concurrently with the oldest nuclear component which indicates that the control of aging may be a “dominant” or active process in the true slime molds. Age heteroplasmons using transfilter contact between two plasmodia across 1 μ pore size Nucleopore membrane filters were also produced which indicates that senescence may not be a cytoplasmic infectious particle.