The effect of ultracentrifuging on Paramecium, with special reference to recovery and macronuclear reorganization

摘要: Paramecium caudatum becomes much elongated upon centrifuging at 21,000 times gravity. The chromatin is sometimes forced from the achromatic matrix of macronucleus. materials in cell are redistributed according to their relative specific gravities as follows: At centrifugal end cell, crystals, layer fluid, micronucleus and macronuclear chromatin, food vacuoles neutral red inclusions, macronucleus, endoplasm with large clear alveoli, fat, centripetal cell. contracting vacuole displaced but not feeding canals or pore. In some cases may be extruded Animals which survive regain usual shape disturbed return distribution rapidly. Sometimes crystals remain compact masses so passed daughter cells fission. two components macronucleus do fuse regenerates an matrix, division somewhat delayed. old persists over a long time interferes division. have no divide, amicronucleate races been established. Apparently necessary for survival P. caudatum; absence replacement occurs micronucleus. membrane temporary.