Effect of Digitonin on Cellular Division: Digitonin mitosis

Olah, L. V.

doi:10.2307/2483368

“…

As previously reported, purified digitonin as a mitotic agent selectively dissocia tes formation of the mitotic spindle from the phragmoplast (Olah 1963(Olah , 1965Underbrink and Olah, 1963, 1965, 1968. Digitonin mitosis is characterized by a selectively suppressed spindle and development of a garbled phragmoplast which produces a geometrically upset, branched cell wall system associated with the restitut ing tetraploid nucleus.

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confidence: 86%

Effect of Digitonin on Cellular Division

Olah¹,

Bozzola²

1972

CYTOLOGIA

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As previously reported, purified digitonin as a mitotic agent selectively dissocia tes formation of the mitotic spindle from the phragmoplast (Olah 1963(Olah , 1965Underbrink and Olah, 1963, 1965, 1968. Digitonin mitosis is characterized by a selectively suppressed spindle and development of a garbled phragmoplast which produces a geometrically upset, branched cell wall system associated with the restitut ing tetraploid nucleus. This constant and characteristic association deserves further study. Extensive information concerning the chemical nature of the cell plate and wall system found in this substance was published earlier (Olah 1965).Mitotic figures in treated cells may be classified into two categories: 1) Cells with arrested metaphases identical to those found during colchicine metaphase, showing randomly scattered chromosomes and no trace of rudimentary spindle substance (Figs. 1-3). At anaphase, only cytoplasmic drifting seems to account for chromatidial movement. 2) Cells showing partial stathmokinetic effect charac terized by limited "polarized" movement forming groups of separated chromatids and/or chromosomes (Fig. 4).The problem of whether both types of cells are able to form nuclei with the associated phragmoplast material was investigated by determining the frequency of both types of cells, and comparing this with the frequency of tetraploid nuclei with and without associated phragmoplast substance. In addition, we: studied development, structure and birefringency of post-mitotic cell wall complexes in treated cells; studied the course of the second and subsequent divisions of cells which underwent one digitonin mitosis; investigated incorporation patterns of tritiated thymidine and uridine in treated cells and controls; studied the role of the nucleus involved with phragmoplast association; and compared the digitonin effect with functionally or structurally related substances as tomatin, digitalin, digitoxin, de oxycholate, and Tween 20 (a non-ionic detergent). Materials and methodsRoots of Allium sativum cloves aseptically grown in tap water or 0.5% agar water were treated with 0.25 and 0.50% purified digitonin (courtesy of Merck, Sharp, and Dohme, Inc.) for varying times. Rooted cloves were washed, centri fuged at 6,500 rpm, and recovered in sterile tap water or agar-water. Excised root tips were fixed with Helly, Navashin, Zenker, LaCour 2BE, and Farmer fluids.

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“…Light microscope studies indicated that the reason the cell wall is as sociated with post-mitotic nuclei is because the earlier cell plate initially forms in the hyaline substance which in turn develops among the chromo somes (Olah 1963(Olah , 1965. Electron microscope observations of cells with aberrant phragmoplasts and cell walls have substantiated the light microscope observations (Underbrink andOlah 1963, 1965).…”

Section: Observationsmentioning

confidence: 99%

“…The digitonin mitosis and other cytological effects induced by digitonin have been described (Olah 1963(Olah , 1965. The fine structure of many of the cellular anomalies produced by digitonin, including later stages of phragmoplast and cell plate development have been traced (Underbrink andOlah 1963, 1965).…”

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Effect of Digitonin on Cellular Division

Underbrink

¹

,

Olah²

1968

CYTOLOGIA

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“…The effect of this agent, a foaming saponin of steroid structure called digitonion, was studied on both optical and ultrastructural levels (Olah 1963, 1965, Under brink and Olah 1963, 1965. As a result, a new concept was proposed (Olah 1966).…”

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confidence: 99%