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Electron Microscopy of the Nuclear Apparatus of Urostyla grandis, A Hypotrichous Ciliate
Author(s) -
INABA FUMIE,
SUGANUMA YOSHIKO
Publication year - 1966
Publication title -
the journal of protozoology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.067
H-Index - 77
eISSN - 1550-7408
pISSN - 0022-3921
DOI - 10.1111/j.1550-7408.1966.tb01884.x
Subject(s) - ciliate , electron microscope , materials science , biology , optics , physics , paleontology
SYNOPSIS. A description is given of the interphase nuclear apparatus of Urostyla grandis , which has many macronuclei and a few micronuclei. The macronucleus is bounded by a typical double envelope. Chromatinic material in the macronucleus forms a large, irregular network composed of threads up to 500 mμ in thickness which are thicker than those in the macronuclei of most ciliates. The nucleoli are round bodies about 1–2 μ in diameter and are embedded in the matrix enclosed in chromatin threads. The micronucleus is bounded by a double, porous envelope similar to that of the macronucleus. Chromatinic material in the micronucleus forms a small network of comparatively thin threads, 60–80 mμ thick. At high magnifications, both the chromatin threads in the macronucleus and in the micronucleus appear to be composed of fine twisted fibrils about 10 mμ thick. The reorganization band which traverses each macronucleus in the late interphase is divided into two zones: the forward zone consists of fine, twisted fibrils 30 mμ thick formed by pairs of parallel fibrils each 10 mμ thick. The rear zone consists of small chromatin bodies and thin threads, both 80 mμ in diameter, consisting of fine fibrils 10 mμ thick. Reorganized chromatin threads appear to be thin spiral threads 80–130 mμ thick in striking contrast to the thick threads of 100–500 mμ diameter composing the large, irregular network observed in the early interphase macronucleus.