Somatic mitosis in haploid and diploid strains of Cochliobolus sativus

1974 ◽  
Vol 52 (7) ◽  
pp. 1561-1568 ◽  
Author(s):  
H. C. Huang ◽  
R. D. Tinline
Keyword(s):  
Nuclear Division ◽  
Spindle Pole Body ◽  
Metaphase Plate ◽  
Spindle Pole ◽  
Cochliobolus Sativus ◽  
Haploid Number ◽  
Diploid Strain ◽  
Spindle Poles ◽  
Pole Body ◽  
Partial Synchrony

From examination of living and doubly stained nuclei, somatic nuclear division in a haploid and a diploid strain of Cochliobolus sativus resembles conventional mitosis in that a metaphase-plate-like configuration and an associated fusiform spindle were present. However, a spindle pole body located at the spindle poles, the nucleolus, and presumably, the nuclear envelope persisted throughout the division cycle. During division, chromosomes contracted and the spindle elongated. At anaphase, lagging chromosomes were invariably observed.Within multinucleate cells there was variation in the degree of synchrony of nuclear division. Most, however, showed partial synchrony with the gradient direction basipetal in the diploid, acropetal in the haploid. Diploid and haploid nuclei also differed in size, in the size of spindle, number and probably in the size of chromatinic elements, and sometimes in the number of nucleoli. The haploid number of chromosomes appears to be six to eight.

Ultrastructure of somatic mitosis in a diploid strain of the plant pathogenic fungus Cochliobolus sativus

1975 ◽  
Vol 53 (4) ◽  
pp. 403-414 ◽  
Author(s):  
H. C. Huang ◽  
R. D. Tinline ◽  
L. C. Fowke
Keyword(s):  
Nuclear Envelope ◽  
Ultrastructural Study ◽  
Pathogenic Fungus ◽  
Spindle Pole Body ◽  
Spindle Pole ◽  
Cochliobolus Sativus ◽  
Diploid Strain ◽  
Interphase Nuclei ◽  
Pole Body ◽  
Spindle Microtubules

An ultrastructural study of mitosis in a diploid strain of Cochliobolus sativus showed the event to be intranuclear. Two nucleoli occasionally were present in interphase nuclei. During division the spindle pole body peripheral to the nuclear envelope divided; spindle microtubules radiated into the nucleoplasm from the amorphous granular region abutting the nuclear envelope beneath the bodies; chromosomes condensed at prophase, approached the equatorial plane at metaphase, and moved asynchronously at anaphase; single microtubules appeared attached to kinetochore-like structures. At telophase, nuclei exhibited maximal elongation; fissures of the nuclear envelope appeared in the interzonal region; the nucleolus dispersed. The polar nuclear areas became new daughter nuclei with nucleoli.

scholarly journals Conservative Duplication of Spindle Poles during Meiosis in Saccharomyces cerevisiae

2001 ◽  
Vol 183 (7) ◽  
pp. 2372-2375 ◽  
Author(s):  
Andreas Wesp ◽  
Susanne Prinz ◽  
Gerald R. Fink
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Spindle Pole Body ◽  
Spindle Pole ◽  
Spore Formation ◽  
Wild Type ◽  
Body Distribution ◽  
Spindle Poles ◽  
Pole Body ◽  
Spindle Pole Bodies ◽  
Type Strains

ABSTRACT During sporulation in diploid Saccharomyces cerevisiae, spindle pole bodies acquire the so-called meiotic plaque, a prerequisite for spore formation. Mpc70p is a component of the meiotic plaque and is thus essential for spore formation. We show here that MPC70/mpc70 heterozygous strains most often produce two spores instead of four and that these spores are always nonsisters. In wild-type strains, Mpc70p localizes to all four spindle pole bodies, whereas in MPC70/mpc70 strains Mpc70p localizes to only two of the four spindle pole bodies, and these are always nonsisters. Our data can be explained by conservative spindle pole body distribution in which the two newly synthesized meiosis II spindle pole bodies of MPC70/mpc70 strains lack Mpc70p.

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.

Assembly and dynamics of an anastral:astral spindle: the meiosis II spindle of Drosophila oocytes

1998 ◽  
Vol 111 (17) ◽  
pp. 2487-2495 ◽  
Author(s):  
S.A. Endow ◽  
D.J. Komma
Keyword(s):  
De Novo ◽  
Spindle Pole Body ◽  
Spindle Pole ◽  
The Body ◽  
Central Spindle ◽  
Spindle Poles ◽  
Pole Body ◽  
Microtubule Motor ◽  
Gamma Tubulin ◽  
Meiosis I

The meiosis II spindle of Drosophila oocytes is distinctive in structure, consisting of two tandem spindles with anastral distal poles and an aster-associated spindle pole body between the central poles. Assembly of the anastral:astral meiosis II spindle occurs by reorganization of the meiosis I spindle, without breakdown of the meiosis I spindle. The unusual disk- or ring-shaped central spindle pole body forms de novo in the center of the elongated meiosis I spindle, followed by formation of the central spindle poles. gamma-Tubulin transiently localizes to the central spindle pole body, implying that the body acts as a microtubule nucleating center for assembly of the central poles. Localization of gamma-tubulin to the meiosis II spindle is dependent on the microtubule motor protein, Nonclaret disjunctional (Ncd). Absence of Ncd results in loss of gamma-tubulin localization to the spindle and destabilization of microtubules in the central region of the spindle. Assembly of the anastral:astral meiosis II spindle probably involves rapid reassortment of microtubule plus and minus ends in the center of the meiosis I spindle - this can be accounted for by a model that also accounts for the loss of gamma-tubulin localization to the spindle and destabilization of microtubules in the absence of Ncd.

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 ADY1, A Novel Gene Required for Prospore Membrane Formation at Selected Spindle Poles inSaccharomyces cerevisiae

2001 ◽  
Vol 12 (9) ◽  
pp. 2646-2659 ◽  
Author(s):  
Changchun Deng ◽  
William S. Saunders
Keyword(s):  
Meiotic Chromosome ◽  
Spindle Pole Body ◽  
Spindle Pole ◽  
Membrane Formation ◽  
Spindle Poles ◽  
Pole Body ◽  
Spindle Pole Bodies ◽  
Prospore Membrane ◽  
A Cell ◽  
Body Component

ADY1 is identified in a genetic screen for genes on chromosome VIII of Saccharomyces cerevisiae that are required for sporulation. ADY1 is not required for meiotic recombination or meiotic chromosome segregation, but it is required for the formation of four spores inside an ascus. In the absence of ADY1, prospore formation is restricted to mainly one or two spindle poles per cell. Moreover, the two spores in the dyads of the ady1 mutant are predominantly nonsisters, suggesting that the proficiency to form prospores is not randomly distributed to the four spindle poles in theady1 mutant. Interestingly, the meiosis-specific spindle pole body component Mpc54p, which is known to be required for prospore membrane formation, is localized predominantly to only one or two spindle poles per cell in the ady1 mutant. A partially functional Myc-Pfs1p is localized to the nucleus of mononucleate meiotic cells but not to the spindle pole body or prospore membrane. These results suggest that Pfs1p is specifically required for prospore formation at selected spindle poles, most likely by ensuring the functionality of all four spindle pole bodies of a cell during meiosis II.

Mitosis and septum formation in the basidiomycete Helicobasidium mompa

1986 ◽  
Vol 64 (1) ◽  
pp. 130-145 ◽  
Author(s):  
Timothy M. Bourett ◽  
David J. McLaughlin
Keyword(s):  
Endoplasmic Reticulum ◽  
Functional Significance ◽  
Spindle Pole Body ◽  
Spindle Pole ◽  
Multivesicular Bodies ◽  
Spindle Poles ◽  
Astral Microtubule ◽  
Pole Body ◽  
Helicobasidium Mompa ◽  
Spindle Elongation

Mitosis in clampless, dikaryotic hyphae of Helicobasidium mompa (Basidiomycota, Auriculariales sensu lato) was studied in apical and penultimate cells by correlating light microscopic and ultrastructural observations. Mitosis lasts about 10.5 min. In penultimate cells, mitosis occurs in the base of a branch whose initiation involves rupture of the wall. The extranuclear interphase spindle pole body contains two three-layered discs. Prophase is discerned by the polarization of the nucleus into a karyokinetic and a nucleolar region. During prometaphase, the spindle pole body discs move into the plane of the nuclear envelope where they occupy gaps. The spindle pole is enclosed by a cap of endoplasmic reticulum. At metaphase, nuclei lie side by side, the nucleolus resides in a nuclear evagination, and the spindle pole body discs are five layered. At anaphase, both chromatin to pole movement and extensive spindle elongation occur, astral microtubule populations reach a maximum, and multivesicular bodies aggregate at the spindle poles. Septa contain simple pores and form at the site previously occupied by the dividing nuclei. The results are compared with mitotic cycles in higher fungi and their evolutionary, phylogenetic, and functional significance is discussed.

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