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Rapid patterning in 2‐D cultures of Dictyostelium cells and its relationship to zonal differentiation
Author(s) -
Hirano Takashi,
Sawai Satoshi,
Sawada Yasuji,
Maeda Yasuo
Publication year - 2000
Publication title -
development, growth and differentiation
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.864
H-Index - 66
eISSN - 1440-169X
pISSN - 0012-1592
DOI - 10.1046/j.1440-169x.2000.00541.x
Subject(s) - dictyostelium discoideum , border cells , oxidative phosphorylation , microbiology and biotechnology , chemistry , slime mold , biophysics , cellular differentiation , cell , biology , biochemistry , gene
Rapid patterning has been observed in confined 2‐D cultures of Dictyostelium discoideum Ax‐2 cells as an outer dark zone and a inner light zone. The width of outer zone was usually ~100 μm, irrespective of the size of cell masses under atmospheric conditions. The width of the outer zone, however, changed depending on external O 2 concentrations and reached up to 250 μm at 100% O 2 . A clear regional difference in tetramethyl rhodamine methyl ester (TMRM) staining was noticed between the outer zone and the inner zone: the inner zone was more strongly stained with TMRM than the outer zone, which faced the air. Using inhibitors of oxidative phosphorylation (dinitrophenol (DNP) or NaN 3 ) and a specific inhibitor of CN‐resistant respiration (benzohydroxamic acid (BHAM)), it has been demonstrated that the outer zone is basically formed by the O 2 threshold for oxidative phosphorylation, while the inner cells mainly perform cyanide‐resistant respiration. When cells around the early mound stage (just before prestalk and prespore differentiation) were cultured as 2‐D cell masses, ecmA ‐expressing cells (pstA cells), ecmB ‐expressing cells (pstB cells) and D19‐expressing cells (prespore; psp cells), arose in a position‐dependent manner in the outer zone. In the inner zone, cell motility seemed to be markedly impaired and neither prestalk nor prespore differentiation occurred. In addition, once‐differentiated prespore cells were found to dedifferentiate rapidly in the inner zone. The reason for dedifferentiation as well as for failure of cells to differentiate in the inner zone is discussed with reference to O 2 radicals.