title: A cell-cycle-phase-specific mutant of amoeba.
abstract: The treatment of Amoeba indica with ethylmethanesulphonate (EMS) at early S, late S and late G2 phases of the cell cycle leads to the production of mini amoeba cells in the G2 period. Among them, only a few of the mini cells that originated from EMS treatment at early S phase have been found to be viable and to give rise to stable clones. These mini amoebae show stable and altered characteristic features in cell size, structure, membrane properties, cell-cycle timing and the patterns of macromolecular syntheses as compared to the parental cells. It is suggested that the mini amoeba cell is a size mutant that has a cell-cycle-phase-specific origin. The finding is discussed in relation to preferential mutagenic action involving the functional state of DNA leading to the production of viable mutant amoebae.
mesh_terms: D000656:Amoeba / Q000187:drug effects / Q000378:metabolism / Q000502:physiology* / Q000648:ultrastructure; D000818:Animals; D002453:Cell Cycle; D002462:Cell Membrane / Q000648:ultrastructure; D002467:Cell Nucleus / Q000648:ultrastructure; D004247:DNA / Q000096:biosynthesis; D004721:Endoplasmic Reticulum / Q000648:ultrastructure; D005020:Ethyl Methanesulfonate / Q000494:pharmacology; D007399:Interphase / Q000187:drug effects; D008854:Microscopy, Electron; D009154:Mutation; D014176:Protein Biosynthesis
chemical_list: D004247:DNA; D005020:Ethyl Methanesulfonate