Influence of extract from shoots of Taxus baccata var. elegantissima on ultrastructure and tubulin cytoskeleton of meristematic cells of Allium cepa L. roots

We investigated the influence of extract from Taxus baccata var. Elegantissima (TbE) shoots in 1:8 dilution, containing paclitaxel in concentration of 81,6 µg/g fresh mass on ultrastructure and tubulin cytoskeleton of meristematic cells of Allium cepa L. root tips. Incubation time 3, 6, 12 and 24 h was followed with postincubation in water for 12 and 24 h. During shorter incubation (till 12 h) the surface of the cell nuclei decreased and chromatin became condensed (in comparison to control) but after 24 h the average surface increased and chromatin condensation decreased. In the course of incubation the average size of plastids and vacuoles increased. Moreover, after treatment mitochondria and plastids showed degradation of ultrastructure, which was reversed after 12 h of postincubation. Immunocytochemical assays demonstrated that in the course of incubation in the ThE extract, the tubulin cytoskeleton became partially disorganised. In most interphase cells, cortical microtubules (MTs) lost their oval transverse orientation. The preprophase band (PPB) position in the cell was often asymmetrical. The MTs array of the karyokinetic spindle and phragmoplast was also disturbed. These alterations were completely reversed during postincubation.

Download Full-text

The preprophase band: possible involvement in the formation of the cell wall

Journal of Cell Science ◽

10.1242/jcs.22.2.403 ◽

1976 ◽

Vol 22 (2) ◽

pp. 403-411 ◽

Cited By ~ 1

Author(s):

M.J. Packard ◽

S.M. Stack

Keyword(s):

Cell Wall ◽

Allium Cepa ◽

Cell Walls ◽

Preprophase Band ◽

Adjacent Cell ◽

Root Tips ◽

Meristematic Cells ◽

Narrow Region ◽

The Matrix

Numerous vesicles were observed among the microtubules of the “preprophase” band in prophase cells from root tips of Allium cepa. The content of these vesicles looks similar to the matrix of adjacent cell walls, and these vesicles often appear to be involved in exocytosis. In addition, the cell walls perpendicular to the plane of (beneath) the preprophase band are often differentially thickened compared to the walls lying parallel to the plane of the band. Our interpretation of these observations is that the preprophase band may direct or channel vesicles containing precursors of the cell wall to localized regions of wall synthesis. The incorporation of constituents of the cell wall into a narrow region defined by the position of the preprophase band may be a mechanism that ensures unidirecitonal growth of meristematic cells.

Download Full-text

Loss of Microtubules in the Interphase Cells of Onion (Allium cepa L.) Root Tips from the Cell Cortex and Their Appearance in the Cytoplasm after Treatment with Cycloheximide

PLANT PHYSIOLOGY ◽

10.1104/pp.104.1.281 ◽

1994 ◽

Vol 104 (1) ◽

pp. 281-284 ◽

Cited By ~ 20

Author(s):

Y. Mineyuki ◽

H. Iida ◽

Y. Anraku

Keyword(s):

Allium Cepa ◽

Cell Cortex ◽

Root Tips ◽

Allium Cepa L ◽

Interphase Cells

Download Full-text

Antimitotic effect, G2/M accumulation, chromosomal and ultrastructure changes in meristematic cells of Allium cepa L. root tips treated with the extract from Rhodiola rosea roots

Caryologia ◽

10.1080/00087114.2003.10589343 ◽

2003 ◽

Vol 56 (3) ◽

pp. 337-351 ◽

Cited By ~ 29

Author(s):

Agnieszka Majewska ◽

Ewa Wolska ◽

Elwira Śliwińska ◽

Mirosława Furmanowa ◽

Natalia Urbańska ◽

...

Keyword(s):

Allium Cepa ◽

Rhodiola Rosea ◽

Root Tips ◽

Meristematic Cells ◽

Allium Cepa L ◽

Antimitotic Effect

Download Full-text

Actin in the preprophase band of Allium cepa.

The Journal of Cell Biology ◽

10.1083/jcb.104.6.1515 ◽

1987 ◽

Vol 104 (6) ◽

pp. 1515-1519 ◽

Cited By ~ 87

Author(s):

B A Palevitz

Keyword(s):

Thin Layer ◽

Allium Cepa ◽

Colchicine Treatment ◽

Preprophase Band ◽

Fluorescence Microscope ◽

Root Tips ◽

Rhodamine Phalloidin ◽

Interphase Cells ◽

Triton X

F-actin has been identified in the preprophase band of Allium cepa. Cells attached to subbed slides were obtained from formaldehyde-fixed root tips digested in EGTA and Cellulysin. The air-dried cells were extracted in Triton X-100, treated with rhodamine-phalloidin, rinsed briefly in PBS, and viewed in the fluorescence microscope. Interphase cells contain a network of actin fibers that extends into all areas of the cytoplasm. During preprophase, the network is replaced by a band of fibers aligned in the position of the preprophase band. Colocalization of F-actin with rhodamine-phalloidin and microtubules with tubulin immunocytochemistry confirms that the two bands are coincident. The actin appears to comprise a thin layer of fibers next to the plasmalemma. Like the microtubule preprophase band, the actin band narrows as preprophase progresses and disappears by midprophase. Fluorescent actin bands are not seen in fixed cells pretreated with excess unlabeled phalloidin before staining. They are also absent in roots exposed to cytochalasins B and D before fixation, but preprophase band microtubules at all stages of aggregation are still present. Colchicine treatment leads to the loss of both preprophase band microtubules and actin. The possible function of preprophase band actin is discussed.

Download Full-text

Influence of extract from shoots of Taxus baccata var. 'Elegantissima' on mitotic activity of meristematic cells of Allium cepa L. roots

Acta Societatis Botanicorum Poloniae ◽

10.5586/asbp.2000.024 ◽

2014 ◽

Vol 69 (3) ◽

pp. 185-192 ◽

Cited By ~ 9

Author(s):

Agnieszka Majewska ◽

Mirosława Furmanowa ◽

Elwira Śliwińska ◽

Kazimierz Głowniak ◽

Joanna Guzewska ◽

...

Keyword(s):

Flow Cytometry ◽

Mitotic Activity ◽

Genetic Material ◽

Taxus Baccata ◽

Alcoholic Extract ◽

Root Tips ◽

Meristematic Cells ◽

Allium Cepa L ◽

G2 Phase ◽

Number Of Cells

We investigated the influence of different concentrations of alcoholic extract from young shoots of Taxus baccata var. 'Elegantissima' (TbE), containing paclitaxel (81.6 µg/g fresh mass), on mitotic activity and DNA content in meristematic ` cells of Allium cepn adventitious root tips. During 24 hours of incubation we obtained different level of inhibition of mitotic activity: ranging from slight changes (dilution 1:32), through complete inhibition reversible in postincubation (dilution 1:8), to whole inhibition irreversible in postincubation (dilution 1:4). Inhibition of mitotic activity was connected with an increase of prophases and metaphases and changes in morphology of chromosomes (thick chromosomes of prophases with diluted karyolymph and c-metaphases). During the experiment, the number of aberrations and micronuclei didn't increase but the number of cells with replicated DNA (4C) blocked in G2 phase was higher. This study was done by a flow cytometry method. The optimal concentration of the TbE extract, which inhibited mitotic activity, did not damage the genetic material (chromosomes) visibly.

Download Full-text

Telomere arrangement in differentiated interphase cells of Allium cepa: a function of chromosome arm lengths at anaphase–telophase

Canadian Journal of Genetics and Cytology ◽

10.1139/g83-072 ◽

1983 ◽

Vol 25 (5) ◽

pp. 478-486 ◽

Cited By ~ 6

Author(s):

Catharine P. Fussell

Keyword(s):

Nuclear Envelope ◽

Allium Cepa ◽

Interphase Nucleus ◽

Interphase Nuclei ◽

Meristematic Cells ◽

Differentiated Cells ◽

Allium Cepa L ◽

Interphase Cells ◽

Chromosome Arm ◽

Latitudinal Band

The arrangement of telomeres in eight types of differentiated Allium cepa L. interphase cells was studied to find whether the distribution pattern varies with differentiation as centromere distribution appears to in differentiated cells of mice and Triturus vulgaris L. The results show that telomere positions and groupings in A. cepa are essentially the same in differentiated and meristematic interphase nuclei; telomeres, which are roughly paired, are arranged in a telophase configuration along one side of the nucleus. Thus telomeres appear to maintain the same basic arrangement in differentiated and in meristematic cells. Comparison of chromosome arm lengths and interphase telomere positions suggests that interphase telomere arrangements are a function of chromosome arm lengths at the time the nuclear envelope forms. Such an arrangement would place homologous telomeres in the same latitudinal band of the interphase nucleus.

Download Full-text