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Stimulation of Mitosis Following Fusion of Plasmodia in the Myxomycete Physarum polycephalum
Abstract
SUMMARY: Rapid fusion after contact between multinucleate, naturally synchronous plasmodia of the same strain of Physarum polycephalum was demonstrated by autoradiography. Fusion between plasmodia of equal size at the same stage in the mitotic cycle resulted in synchronous mitosis with a delay. This delay was slight if the nuclei were about to undergo mitosis at the time of fusion, but increased in a roughly linear fashion to about 4 h in plasmodia fused at an early stage in the mitotic cycle. Fusion between plasmodia at different stages in the mitotic cycle also resulted in synchronous mitosis, division of nuclei late in the cycle being delayed and of those early in the cycle being accelerated. When both plasmodia were in mid-interphase, the amount of acceleration was proportional to the difference in stages at the time of fusion, a 5 h phase difference giving about 3 h acceleration. However, non-synchronous mitosis resulted when a plasmodium about to undergo mitosis was fused with one earlier in the nuclear cycle, the nuclei in the former plasmodium presumably having reached a stage at which retardation could not occur.
- Accepted:
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© Society for General Microbiology, 1962