Clonal Development of the True Slime Mould, Didymium nigripes

SUMMARY: Didymium nigripes has been grown in two-membered cultures with Aerobacter aerogenes as its bacterial associate. All phases of the developmental cycle were observed, including spore germination, myxamoeboid growth, plasmodium formation and growth, and fruiting. Both spores and myxamoebae have regularly yielded clonal populations displaying normal development terminating with the appearance of fruits. Efficiency of plating determinations showed that spores and myxamoebae were 100 % viable under the proper conditions. Greatly decreased spore viability was encountered when plasmodia were permitted to fruit in the presence of the metabolic products of their bacterial associate. Plasmodium formation was inhibited by the presence of 2 % (w/v) glucose or 0·2 % (w/v) brucine. However, the myxamoebae grew normally under these conditions.