Somatic nuclear division in the sporidia of Ustilago violacea. II. Observations on living cells with phase-contrast and fluorescence microscopy

1974 ◽  
Vol 20 (5) ◽  
pp. 739-746 ◽  
Author(s):  
N. H. Poon ◽  
A. W. Day
Keyword(s):  
Fluorescence Microscopy ◽  
Acridine Orange ◽  
Phase Contrast ◽  
Nuclear Division ◽  
Spindle Pole Body ◽  
Time Lapse ◽  
Spindle Pole ◽  
Living Cells ◽  
Pole Body ◽  
Orange Fluorescence

Somatic nuclear division in living cells is described under both phase-contrast and acridine orange fluorescence microscopy. The observations confirm a previous description of the division in fixed cells stained with acetic orcein. Acridine orange at the optimum concentration of 75–250 mg/liter complete medium clearly differentiated the nucleolus, chromatinic granules, nucleoplasm, and spindle pole body, as well as indicating changes in RNA content in the cytoplasm during budding. Acridine orange fluorescence was identical in both living and fixed cells. The fluorescence of the spindle pole body indicated that it contains DNA, which may initiate RNA synthesis. Time-lapse phase-contrast observations confirmed that neither the fixation technique nor acridine orange or acetic orcein staining caused noticeable artefacts during division, and provided indisputable evidence for the sequencing of stages. Estimates from the time-lapse observations indicated that the division is quite slow (about 45 min) and that 'prophase' takes about 12 min, 'metaphase' 5 min, and 'anaphase–telophase' about 28 min.

scholarly journals Nuf2, a spindle pole body-associated protein required for nuclear division in yeast.

1994 ◽  
Vol 125 (4) ◽  
pp. 853-866 ◽  
Author(s):  
M A Osborne ◽  
G Schlenstedt ◽  
T Jinks ◽  
P A Silver
Keyword(s):  
Nuclear Division ◽  
Spindle Pole Body ◽  
Coiled Coil ◽  
Temperature Shift ◽  
Spindle Pole ◽  
Temperature Sensitive ◽  
Yeast Saccharomyces Cerevisiae ◽  
Culture Cells ◽  
Pole Body ◽  
Associated Proteins

The NUF2 gene of the yeast Saccharomyces cerevisiae encodes an essential 53-kd protein with a high content of potential coiled-coil structure similar to myosin. Nuf2 is associated with the spindle pole body (SPB) as determined by coimmunofluorescence with known SPB proteins. Nuf2 appears to be localized to the intranuclear region and is a candidate for a protein involved in SPB separation. The nuclear association of Nuf2 can be disrupted, in part, by 1 M salt but not by the detergent Triton X-100. All Nuf2 can be removed from nuclei by 8 M urea extraction. In this regard, Nuf2 is similar to other SPB-associated proteins including Nufl/SPC110, also a coiled-coil protein. Temperature-sensitive alleles of NUF2 were generated within the coiled-coil region of Nuf2 and such NUF2 mutant cells rapidly arrest after temperature shift with a single undivided or partially divided nucleus in the bud neck, a shortened mitotic spindle and their DNA fully replicated. In sum, Nuf2 is a protein associated with the SPB that is critical for nuclear division. Anti-Nuf2 antibodies also recognize a mammalian 73-kd protein and display centrosome staining of mammalian tissue culture cells suggesting the presence of a protein with similar function.

scholarly journals Pachytene arrest and other meiotic effects of the start mutations in Saccharomyces cerevisiae.

Genetics ◽  
1989 ◽  
Vol 123 (1) ◽  
pp. 29-43 ◽  
Author(s):  
E O Shuster ◽  
B Byers
Keyword(s):  
Cell Division ◽  
Nuclear Division ◽  
Spindle Pole Body ◽  
Mitotic Cell ◽  
Spindle Pole ◽  
Mitotic Cell Cycle ◽  
Chromosomal Dna ◽  
Pole Body ◽  
Vegetative Cycle

Abstract Mutations in the Start class of cell division cycle genes (CDC28, CDC36 and CDC39) define the point in the G1 phase of the vegetative cycle at which the cell becomes committed to completing another round of cell division. Genetic, cytological and biochemical data demonstrate that these mutations cause meiotic cells to become arrested at pachytene following completion of both chromosomal DNA replication and spindle pole body (SPB) duplication. In contrast these mutations have previously been found to cause arrest of the mitotic cell cycle prior to either of these landmark events, so the role of the Start genes in these events during vegetative growth must be indirect. Our observations are consistent with the hypothesis that CDC28, CDC36 and CDC39 are required for irreversible commitment to nuclear division in both the mitotic and meiotic pathways. CDC28 was additionally found to be required for the SPB separation that precedes spindle formation in preparation for the second meiotic division. Cytological and genetic analyses of this requirement revealed both that such separation may fail independently at either SPB and that ascospore formation can proceed independently of SPB separation.

scholarly journals Nep98p Is a Component of the Yeast Spindle Pole Body and Essential for Nuclear Division and Fusion

2002 ◽  
Vol 278 (11) ◽  
pp. 9938-9943 ◽  
Author(s):  
Shuh-ichi Nishikawa ◽  
Yumiko Terazawa ◽  
Takeshi Nakayama ◽  
Aiko Hirata ◽  
Tadashi Makio ◽  
...  
Keyword(s):  
Nuclear Division ◽  
Spindle Pole Body ◽  
Spindle Pole ◽  
Pole Body

scholarly journals Saccharomyces cerevisiaeCells with Defective Spindle Pole Body Outer Plaques Accomplish Nuclear Migration via Half-Bridge–organized Microtubules

1998 ◽  
Vol 9 (5) ◽  
pp. 977-991 ◽  
Author(s):  
Arndt Brachat ◽  
John V. Kilmartin ◽  
Achim Wach ◽  
Peter Philippsen
Keyword(s):  
Fluorescent Protein ◽  
Spindle Pole Body ◽  
Time Lapse ◽  
Nuclear Migration ◽  
Spindle Pole ◽  
Microtubule Organizing Center ◽  
Multinucleated Cells ◽  
Pole Body ◽  
Cytoplasmic Microtubules ◽  
Low Efficiency

Cnm67p, a novel yeast protein, localizes to the microtubule organizing center, the spindle pole body (SPB). Deletion ofCNM67 (YNL225c) frequently results in spindle misorientation and impaired nuclear migration, leading to the generation of bi- and multinucleated cells (40%). Electron microscopy indicated that CNM67 is required for proper formation of the SPB outer plaque, a structure that nucleates cytoplasmic (astral) microtubules. Interestingly, cytoplasmic microtubules that are essential for spindle orientation and nuclear migration are still present in cnm67Δ1 cells that lack a detectable outer plaque. These microtubules are attached to the SPB half- bridge throughout the cell cycle. This interaction presumably allows for low-efficiency nuclear migration and thus provides a rescue mechanism in the absence of a functional outer plaque. AlthoughCNM67 is not strictly required for mitosis, it is essential for sporulation. Time-lapse microscopy ofcnm67Δ1 cells with green fluorescent protein (GFP)-labeled nuclei indicated that CNM67 is dispensable for nuclear migration (congression) and nuclear fusion during conjugation. This is in agreement with previous data, indicating that cytoplasmic microtubules are organized by the half-bridge during mating.

Ultrastructure of sporulation in the Hemiascomycetes Ascoidea corymbosa, A. rubescens, Cephaloascus fragrans, and Saccharomycopsis capsularis

1979 ◽  
Vol 57 (11) ◽  
pp. 1259-1284 ◽  
Author(s):  
M. L. Ashton ◽  
P. B. Moens
Keyword(s):  
Nuclear Division ◽  
Spindle Pole Body ◽  
Spindle Pole ◽  
Taxonomic Position ◽  
Serial Sections ◽  
Pole Body

Sporulation in four species belonging to three different families of the Hemiascomycetes is described from serial sections. The results show that in each species the formation of the ascospore wall is initiated at a specialized spindle pole body. Spore delimitation proceeds concurrently with the last nuclear division in the ascus. The findings support the taxonomic position that these species belong to a group that includes the yeasts but that is distinct from the Euascomycetes.

Meiosis, septal pore architecture, and systematic position of the heterobasidiomycetous fern parasite Herpobasidium filicinum

1994 ◽  
Vol 72 (9) ◽  
pp. 1229-1242 ◽  
Author(s):  
Robert Bauer ◽  
Franz Oberwinkler
Keyword(s):  
Nuclear Division ◽  
Light And Electron Microscopy ◽  
Spindle Pole Body ◽  
Spindle Pole ◽  
Systematic Position ◽  
Pole Body ◽  
Phylogenetic Implications ◽  
Septal Pores ◽  
Unusual Type ◽  
Nuclear Features

Meiosis, spindle pole body cycle and septal pores in Herpobasidium filicinum were examined using light and electron microscopy and compared with findings in the Uredinales and other simple-pored heterobasidiomycetes. The septal pore apparatus in Herpobasidium filicinum is rustlike, and the nuclear characteristics are also similar but not identical to those found in the Uredinales. Some details, such as the spindle pole body behaviour at prophase, the presence of a complete wrapping of endoplasmic reticulum surrounding the nucleus during division, the extension of the spindle pole body into the cytoplasm during division, and the nucleolus behaviour, distinguish Herpobasidium filicinum from the rusts. On the other hand, nuclear division and spindle pole body characteristics in Herpobasidium filicinum show some features common with Cryptomycocolax abnorme. However, Herpobasidium filicinum shares more important nuclear features with Pachnocybe ferruginea, Eocronartium muscicola, Helicobasidium mompa, and Helicobasidium brebissonii than with the Uredinales or Cryptomycocolacales. Apart from the phylogenetic implications of the ultrastructural data, the most interesting observation in the present work is the unusual type of meiosis. No evidence for meiosis II was found in basidia of Herpobasidium filicinum. Instead, the genesis of the interphase I spindle pole body in Herpobasidium filicinum is essentially identical to the basidiomycetous postmeiotic and intermitotic spindle pole body duplication. Key words: Herpobasidium filicinum, heterobasidiomycetes, meiosis, septal pore, spindle pole body, ultrastructure.

Oscillatory nuclear movement in fission yeast meiotic prophase is driven by astral microtubules, as revealed by continuous observation of chromosomes and microtubules in living cells

1998 ◽  
Vol 111 (6) ◽  
pp. 701-712 ◽  
Author(s):  
D.Q. Ding ◽  
Y. Chikashige ◽  
T. Haraguchi ◽  
Y. Hiraoka
Keyword(s):  
Fission Yeast ◽  
Meiotic Prophase ◽  
Fluorescent Protein ◽  
Dynamic Instability ◽  
Spindle Pole Body ◽  
Spindle Pole ◽  
Living Cells ◽  
Continuous Observation ◽  
Nuclear Movement ◽  
Pole Body

Using a computerized fluorescence microscope system to observe fluorescently stained cellular structures in vivo, we have examined the dynamics of chromosomes and microtubules during the process of meiosis in the fission yeast Schizosaccharomyces pombe. Fission yeast meiotic prophase is characterized by a distinctive type of nuclear movement that is led by telomeres clustered at the spindle-pole body (the centrosome-equivalent structure in fungi): the nucleus oscillates back and forth along the cell axis, moving continuously between the two ends of the cell for some hours prior to the meiotic divisions. To obtain a dynamic view of this oscillatory nuclear movement in meiotic prophase, we visualized microtubules and chromosomes in living cells using jellyfish green fluorescent protein fused with alpha-tubulin and a DNA-specific fluorescent dye, Hoechst 33342, respectively. Continuous observation of chromosomes and microtubules in these cells demonstrated that the oscillatory nuclear movement is mediated by dynamic reorganization of astral microtubules originating from the spindle-pole body. During each half-oscillatory period, the microtubules extending rearward from the leading edge of the nucleus elongate to drive the nucleus to one end of the cell. When the nucleus reversed direction, its motion during the second half of the oscillation was not driven by the same microtubules that drove its motion during the first half, but rather by newly assembled microtubules. Reversible inhibition of nuclear movement by an inhibitor of microtubule polymerization, thiabendazole, confirmed the involvement of astral microtubules in oscillatory nuclear movement. The speed of the movement fluctuated within a range 0 to 15 micron/minute, with an average of about 5 microm/minute. We propose a model in which the oscillatory nuclear movement is mediated by dynamic instability and selective stabilization of astral microtubules.

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