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Chromosome orientation and behavior during prometaphase of mitosis in PtK1 rat kangaroo cells were investigated by cinémicrography and electron microscopy. The first chromosome movements occur soon after the nuclear envelope begins to break down in the region near each pole. Initial chromosome behavior is primarily determined by the distance from the(More)
The nucleotide sequence of a 2.4 kb Dral-EcoRV fragment of pColD-CA23 DNA was determined. The segment of DNA contained the colicin D structural gene (cda) and the colicin D immunity gene (cdi). From the nucleotide sequence it was deduced that colicin D had a molecular weight of 74,683 D and that the immunity protein had a molecular weight of 10,057 D. The(More)
Myxamebas of Polysphondylium violaceum were grown in liquid medium and processed for electron microscopy. Mitosis is characterized by a persistent nuclear envelope, ring-shaped extranuclear spindle pole bodies (SPBs), a central spindle spatially separated from the chromosomal microtubules, well-differentiated kinetochores, and dispersion of the nucleoli.(More)
The antitubulin fungicide benomyl suppressed the linear growth of Neurospora crassa wild type strain St. Lawrence 74 at micromolar concentrations. The rate of germination of macroconidia was not affected. Macroconidia exposed to 1.7 microM benomyl for 5 h formed multiple germ tubes. When germlings incubated for 4 h were exposed to 1.7 microM benomyl for 3(More)
Amebae of D. discoideum on coverslips were fixed in situ with glutaraldehyde and permeabilized with Triton X-100. Of six antibodies tested, only a monoclonal antibody to yeast tubulin consistently gave bright fluorescence. Counterstaining with DAPI facilitated the identification of interphase and mitotic stages. Most microtubules (MTs) in interphase amebae(More)
We studied mitosis in vegetative amebae of Dictyostelium discoideum by phase-contrast microscopy of live and flat-embedded cells, by time-lapse microcinematography, and by electron microscopy of ultrathin sections. The mean time from early prophase to the end of cytokinesis was 10 min 32 s (range: 6 min 23 s to 15 min 40 s). The start of anaphase divided(More)
Ten mitotic spindles from Dictyostelium discoideum have been studied by electron microscopy of serial sections. We have used computer graphics to track individual microtubules (MTs) in three dimensions and to compare seven spindles at different stages of anaphase and telophase. The central spindle of early anaphase is formed by the interdigitation of two(More)
Expression of genes involved in nikkomycin production in Streptomyces tendae was investigated by two-dimensional gel electrophoresis of cellular proteins. Ten gene products (P1-P10) were identified that were synthesized when nikkomycin was produced; these proteins were not detected in non-producing mutants. N-terminal sequences of six of the 10 proteins(More)