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Mitosis in the Rhizopod Lesquereusia spiralis
Author(s) -
STUMP ALEX B.
Publication year - 1959
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.1550-7408.1959.tb03949.x
Subject(s) - telophase , anaphase , nucleus , prophase , mitosis , metaphase , microbiology and biotechnology , biology , interphase , spindle apparatus , phragmoplast , nuclear membrane , anatomy , biophysics , cell division , meiosis , chromosome , cell cycle , genetics , cell , gene
SYNOPSIS. The interphase nucleus of Lesquereusia spiralis , a testate rhizopod, 20–25 μ in diameter, contains 40–50 endosomes and a diffuse granular reticulum. Onset of nuclear division is marked by a cessation of pseudopod activity. Prophase changes include increase in size of the nucleus, disappearance of the endosomes except the peripheral ones, formation of 175–200 chromosomes from the reticulum, and the appearance of spindle fibers. By the end of prophase a well formed equatorial plate is present. The metaphase nucleus is slightly smaller and elongated; the chromosomes remain distinct. In anaphase the nucleus continues to elongate along the polar axis; the chromosomes apparently split lengthwise and polar caps appear. The nucleus elongates further so that by telophase it has become hour‐glass shaped. The spindle fibers are now twisted. Separation of the nuclei takes place in the neck region. The nuclear membrane is unbroken during the process and peripheral endosomes are present at all stages. Total time for mitosis averages 45 minutes.