The effects of high hydrostatic pressure upon cell division in Arbacia eggs

✍ Scribed by Marsland, Douglas A.

• Publisher: Wiley (John Wiley & Sons)
• Year: 1938
• Tongue: English
• Weight: 696 KB
• Volume: 12
• Category: Article
• ISSN: 0095-9898
• DOI: 10.1002/jcp.1030120105

✦ Synopsis

THREE FIGURES

Although much attention has been paid t o the problem of cell division, especially as it occurs in the cleaving eggs of marine animals, a clear conception of the factors which are involved is still lacking. Chambers ('19) has proposed that division results from the growth of the asters, which are conceived of as two spheres which possess a firmer consistency than the peripheral cytoplasm. Spek ('18) has considered that a surface tension differential, which develops between the equator and the poles, plays an important role in cleaving the cell, whereas Heiibrunn ( '28) is inclined to believe that the astral fibers exert a pull upon the surface membrane of the cell. Recently Schectman ('37) has contributed evidence indicating that the furrow results from the growth of a cortical layer of gelated protoplasm which extends inward from the equator, growing at the expense of the solated subcortical protoplasm. At present, therefore, it is not possible to decide whether the force which cleaves the cell results from surface tension, contraction, or sol-gel reactions, or from some other process or combination of processes.

It is interesting to note that Schechtman ('37) compares the intrusion of the cleavage furrow to the extrusion of a pseudopodium. This is in close agreement with the ideas expressed in a 'preliminary report (Marsland, '36) of the experiments which are described in this paper. Previously it was demonstrated that the sol-gel reactions which accompany the formation of a pseudopodium are greatly altered 57 ' From supplementary experiments upon the eggs of Paracentrotus lividus, in which the nuclei may be distinguished with certainty, it can be reported that two nuelei, lying almost in contact, are present i n eggs which have suffered a suppression of the first cleavage.