title: Macronuclear response of Paramaecium multimicronucleatum to L-lysine.
abstract: A strain of Paramaecium multimicronucleatum was exposed to a medium containing L-lysine; the concentrations of the amino acid were 0.1%, 0.5% and 1.0% for different sets of experiments. In these two latter concentrations, the macronucleus of the ciliate broke down into innumerable small fragments, the microspheres. The micro-nuclei remained inert. The microspheres left the body of paramaecium as cell-free, self-duplicating entities constituted of DNA and RNA and enveloped by a protein coat. They had no nuclear membrane and they resembled the prokaryotes. Grown in culture medium with 0.1% horse serum, the microspheres transformed into small amoebae having typical eukaryotic features. These amoebae maintained a typical cyst-trophic cycle during the successive sub-cultures; they had no similarity with the paramaecia.
mesh_terms: D000818:Animals; D002467:Cell Nucleus / Q000187:drug effects; D004247:DNA / Q000378:metabolism; D008239:Lysine / Q000494:pharmacology*; D010247:Paramecium / Q000187:drug effects* / Q000254:growth & development / Q000378:metabolism; D012313:RNA / Q000378:metabolism
chemical_list: D012313:RNA; D004247:DNA; D008239:Lysine