Chromosome Analysis and Amitotic Nuclear Division in &lt;i&gt;Nitella axillaris&lt;/i&gt;

Roberts, G. W.; Chen, James C. W.

doi:10.1508/cytologia.40.151

Cited by 4 publications

(3 citation statements)

References 9 publications

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“…The present is the first report of the ultrastructure of amitotic nuclei in corticating cells in Charales. The ultrastructure of amitotic nuclei in corticating cells is similar to those occurring in axial cells of Chara and Nitella (Barton 1967;Pickett-Heaps 1967;Roberts & Chen 1975;Ca ´ceres & Parodi 1985;Parodi & Ca ´ceres 1991;Foissner & Wasteneys 2000; the present study not illustrated).…”

Section: Discussionsupporting

confidence: 75%

Amitosis, including nucleolar behaviour during fragmentation, in both axial and corticating cells of Chara contraria (Charales, Charophyta)

2007

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The results from the present study indicate that in Chara contraria the morphology of amitotic resting nuclei and amitosis depend essentially on the cell type as well to on some extent on the age and development of the cells. Young axial cells of principal axes and branches exhibited C-shaped resting nuclei. During amitosis nuclei initially stretched out and became helical shaped, and they then divided themselves into two similar C-shaped nuclei that remained close to each other. The nucleolar material gradually merged together to eventually form a central nucleolus, which adopted the curving of the nucleus. Spindle-shaped resting nuclei with numerous and irregularly distributed ovoid nucleolar structures were also observed. They duplicated their length during amitosis, underwent a constriction in the middle portion, and finally broke obliquely giving rise to two daughter nuclei, both with similar size. Young corticating cells exhibited initially ovoid nuclei. Then, they gradually stretched out concomitantly with the extension of the cells, giving rise to worm-shaped nuclei that bent irregularly and eventually divided themselves by constriction in portions of different sizes. The ultrastructure of amitotic nuclei in corticating cells was studied. The nuclear envelope remained intact in dividing nuclei. In section, resting nuclei exhibited numerous, small nucleolar profiles homogeneously distributed. In dividing nuclei, in contrast, few, large nucleolar profiles occupied the middle portion of the nucleus. Bundles of 3-66 tubular elements c. 20 nm in diameter ran approximately parallel to the long axis of the nucleus. Tubules were made of circular subunits c. 2 nm in diameter in cross section, and frequently they contacted nucleolar profiles and the inner membrane of the nuclear envelope.

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Section: Discussionsupporting

confidence: 75%

Amitosis, including nucleolar behaviour during fragmentation, in both axial and corticating cells of Chara contraria (Charales, Charophyta)

2007

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“…Obviously, a regulatory mechanism operated to keep the cytoplasm/nucleus ratio constant . This regulatory mechanism might be equivalent to that found during naturally occurring amitosis (26,33,36); it is probably a "means of increasing the nuclear surface and DNA content" (33) .…”

Section: Mechanism Of Multinucleation and Its Physiological Meaningmentioning

confidence: 71%

Formation of multinuclear cells induced by dimethyl sulfoxide: inhibition of cytokinesis and occurrence of novel nuclear division in Dictyostelium cells.

Fukui¹

1980

The Journal of Cell Biology

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Our previous studies showed that 10% dimethyl sulfoxide (DMSO) induces the formation of actin microfilament bundles in the cell nucleus together with the dislocation of cortical microfilaments from the plasma membrane . The present study investigated the effects of DMSO on diverse activities mediated by cellular microfilaments as the second step toward assessing potential differences between nuclear and cytoplasmic actins of Dictyostelium mucoroides. DMSO was found to reversibly inhibit cell-to-glass as well as cell-to-cell adhesion, cell locomotion, and cell multiplication, whereas cytoplasmic streaming and phagocytosis were not obviously inhibited .Also, 5% DMSO inhibited cytokinesis but did not totally inhibit cell growth thus leading to the development of giant cells more than 10 times larger than normal cells. Transmission electron microscopy using serial thin sections showed the occurrence of multinucleation in the DMSO-induced giant cells. After the removal of DMSO, the giant multinuclear cells underwent multiple cytoplasmic cleavage producing normal-sized mononuclear cells.The nuclear division in the DMSO-induced giant cells was unique in that no spindle microtubules were formed, and vesicles appeared inside the nucleus forming a transverse partition of the nuclear envelope . The presence of actin filaments in those nuclei was demonstrated by a binding study with skeletal muscle myosin subfragment-1, and their possible involvement in this mode of nuclear division is discussed .Since Ryser (30) first found microfilaments in the nuclei of Physarum polycephalum, considerable evidence showing the localization of actin in the cell nucleus has accumulated. Ultrastructural studies have proven the existence of actin filaments in mitotic cell nuclei of crane fly (3) and locust (17) testes. Actin has also been identified in nuclear as well as chromosome nonhistone proteins in rat liver (8), P. polycephalum (19), and Dictyostelium discoideum (22). We found that dimethyl sulfoxide (DMSO) induces the formation of huge microfilament bundles of actin in the Dictyostelium nucleus (13). We have shown that this formation of nuclear bundles could also be induced in interphase nuclei of Amoeba proteus, HeLa cells

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“…Certaines catégories de cellules, telles les cellules intemodales du cladome et des phylloïdes, les stipulodes, les cellules spirales de l'oogone, etc. possèdent un noyau qui ne se divise pas par caryocinèse, mais par fragmentation (amitose) conduisant ainsi à la présence de cellules plurinucléées (Gavaudan et Cazalas, 1931 ;Shen, 1967;Roberts et Chen, 1975;Moutschen, 1977).…”

Section: -L'appareil Vegetatif Des Characeesunclassified

Recherches récentes sur les Charophycées: morphogenèse et reproduction sexuée

Guerlesquin¹

1987

Bulletin de la Société Botanique de France. Actualités Botaniqu

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Chromosome Analysis and Amitotic Nuclear Division in <i>Nitella axillaris</i>

Cited by 4 publications

References 9 publications

Amitosis, including nucleolar behaviour during fragmentation, in both axial and corticating cells of Chara contraria (Charales, Charophyta)

Amitosis, including nucleolar behaviour during fragmentation, in both axial and corticating cells of Chara contraria (Charales, Charophyta)

Formation of multinuclear cells induced by dimethyl sulfoxide: inhibition of cytokinesis and occurrence of novel nuclear division in Dictyostelium cells.

Recherches récentes sur les Charophycées: morphogenèse et reproduction sexuée

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