Cytoplasmic Changes in Rous Sarcoma Cells Cultivated in vitro.

Abstract

We have previously reported some nuclear alterations in Rous sarcoma cells grown in pure culture. 1 The following is a brief account of the cytoplasmic changes which are generally developed in Rous sarcoma cells cultivated in vitro.

The most outstanding changes take place in the central area of the cell. The cytoplasm of the central cell region at first takes on a cloudy appearance. Indefinite at first, this zone gradually becomes better defined and finally assumes a very sharp outline (Fig. 1). In general, the segregated central area is 3-6 times as large as the nucleus, is spherical in shape and always appears to be denser than the surrounding cytoplasm, but shows no pronounced structural peculiarities. In the first stage of its development the central area is always somewhat eosinophilic; in the more advanced stage of the segregation process its tinctorial characteristics become rather indefinite; with Giemsa it stains at times slightly red and at times slightly blue, and mostly in mixed tones. The nucleus lie almost invariably outside the central area; in binuclear cells the central area is situated between the two nuclei.

As the result of the segregation of the central cell region the sarcoma cell often appears to be built of two clearly distinct zones—central area and peripheral cytoplasm. The peripheral cytoplasm of the sarcoma cell involved is not only sharply marked off from the central region, but in itself present striking structural and behavioral peculiarities. It possesses the character of a flat membrane constantly changing in outline. The vigorous movement of this membrane never leads to significant displacement of the cell. Pseudopodia projected by these cells have a very unusual aspect (Fig. 2) They often appear as coarse rigid roads, which move in all directions on their base, as on a joint.