title: [Fibrillar actin in the nuclear apparatus of the ciliate Paramecium caudatum].
abstract: Due to their nuclear dualism, ciliates provide a good model for studying the role of actin in spatial organization and transcription activity of the nucleus. The actin in the nuclear apparatus of the ciliate Paramecium caudatum was studied using fluorescently labeled phalloiodin and indirect immunocytochemistry. Fibrillar actin was demonstrated in both of the nuclei. Actin was revealed in the chromatin areas, and was often associated with the periphery of the amplified nucleoli in the macronucleus. Redistribution of actin was observed depending on different physiological state of the cells. Stable infection of the macronulear with the intranuclear endobionts Holospora obtuse led to the loss of nuclear actin accompanied by significant nuclear fragility and redistribution of the phosphorylated form of the actin-binding protein cofilin. Spherical bodies resembling karyosphere were found in the macronuclear anlagen.
authors.forename: K A
authors.initials: KA
authors.lastname: Benken
authors.forename: E V
authors.initials: EV
authors.lastname: Sabaneeva
mesh_terms: D051339:Actin Depolymerizing Factors / Q000096:biosynthesis*; D000199:Actins / Q000096:biosynthesis*; D015153:Blotting, Western; D002466:Cell Nucleolus / Q000648:ultrastructure*; D002467:Cell Nucleus / Q000648:ultrastructure*; D002843:Chromatin / Q000648:ultrastructure; D042281:Holosporaceae / Q000502:physiology / Q000648:ultrastructure; D007150:Immunohistochemistry; D048648:Macronucleus / Q000648:ultrastructure*; D018613:Microscopy, Confocal; D048488:Paramecium caudatum / Q000502:physiology / Q000648:ultrastructure; D010590:Phalloidine / Q000031:analogs & derivatives / Q000032:analysis; D010766:Phosphorylation; D012235:Rhodamines / Q000032:analysis; D013559:Symbiosis
chemical_list: D051339:Actin Depolymerizing Factors; D000199:Actins; D002843:Chromatin; D012235:Rhodamines; D010590:Phalloidine; C041085:tetramethylrhodaminylphalloidine