Cells of different ploidy are often present together in Cryptococcus neoformans strains.
We examined the ploidy of C. neoformans strains using both laser scanning cytometry and a fluorescence microscope equipped with a photomultiplier. Haploid strains consisted of normal-sized cells with a haploid DNA amount. In the cell population there were also large-sized cells with a diploid DNA amount. These large cells in haploid strains were isolated using a Skerman micromanipulator, cultivated, and were able to generate diploid clones. Even after only 3-5 transfers on slants, haploid cells were present in all the diploid clones examined. Conversely, haploid clones obtained by single-cell-isolation of normal-sized cells from haploid strains were also shown to contain diploid cells after 3-5 transfers. Fresh haploid isolates from the environment similarly contained diploid cells after 3-5 transfers. Thus, a cellular ploidy shift was shown to occur widely in C. neoformans strains.
Research Center for Pathogenic Fungi & Microbial Toxicoses, Chiba University, 1-8-1 Inohana, Chuo-ku, Chiba 260-8673, Japan.
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Hata
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Ohkusu
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Aoki
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Ito-Kuwa
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Pienthaweechai
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Takeo
D003455:Cryptococcus neoformans / Q000166:cytology*; D004271:DNA, Fungal / Q000032:analysis; D008856:Microscopy, Fluorescence; D011003:Ploidies
D004271:DNA, Fungal