Specific nuclear elimination in polyploid plasmodia of the slime mold Physarum polycephalum.
In growing plasmodia of the myxomycete Physarum polycephalum (G2-phase), three distinct classes of nuclei with a relative DNA content of 1x, 2x, and 4x are observed in the presumed haploid strain CL. The 2x and 4x species comprise up to 35% and 5% of the nuclei. Quantitative cytofluorometric studies of nuclei isolated in either G2- or S-phase or after FUDR treatment (G1 arrest) show that the three nuclear populations undergo a synchronous mitotic cycle and that the relative DNA content of the nuclear fractions in G-2 phase reflects the 2c, 4c, and 8c state. The heterogeneity of the nuclear population does, however, seem to be restricted to the growth phase. During a starvation period of 4 days that always preceeds sporulation (and also meiosis), the 4c nuclear population is reduced to 7%, 8c nuclei are no longer detected. These results suggest that a mechanism exists in Physarum for the selective detection and elimination of polyploid nuclei.
Werenskiold
A K
AK
Ludwig Institute for Cancer Research, Bern, Inselspital, Switzerland.
Schreckenbach
T
T
Valet
G
G
D002467:Cell Nucleus / Q000032:analysis / Q000648:ultrastructure*; D004261:DNA Replication / Q000187:drug effects; D004271:DNA, Fungal / Q000032:analysis; D005434:Flow Cytometry; D005467:Floxuridine / Q000494:pharmacology; D007399:Interphase; D008938:Mitosis; D010804:Physarum / Q000187:drug effects / Q000254:growth & development / Q000648:ultrastructure*; D011123:Polyploidy
D004271:DNA, Fungal; D005467:Floxuridine