Adhesion of L1210 cells to sulfonated styrene copolymer surfaces: imaging of F-actin AND alpha-actinin.

The static adhesion of living L1210 cells to sulfonated copolymer surfaces of different sulfonic group content and the actin cytoskeleton organization in the adhering cells were studied. The strength of the cell-substratum interaction was estimated by determining the relative number of cells remaining adherent despite experiencing a shearing force equal to 1.25 x 10(-11) N caused by the laminar flow of the medium. The cell-substratum interaction took place in a medium with or without serum. The distribution of F-actin and alpha-actinin in the adhering cells was determined in sequences of fluorescent images of cell optical slices with the use of a computer method of cell image analysis. It was shown that the surface sulfonic groups affect not only the rate and strength of cell-substratum adhesion but also the F-actin and alpha-actinin distribution (in the cell regions near the substratum surface) in cells adhering in the medium containing serum. These proteins, concentrated in the tips of microvilli, were observed as dots. The distinctness (discernibleness) and sizes of these dots depend on the surface content of sulfonic groups. F-actin is located at the periphery of the cells in cells adhering in the medium without serum and alpha-actinin is concentrated in small dots at the periphery and in the central part of the cells.

The method of moments as applied to the study of granulocytes' shape and movement.

The paper presents an approach to the quantitative analysis of the shape and motion of migrating granulocytes based on the method of moments. A computer image analysis system and a specially designed program were used. The following features of cells and cell locomotion have been calculated: the cell centre of gravity and its coordinates, the cell displacement, the main cell axis, the coefficient describing cell elongation and the parameters of cell orientation. In order to evaluate the above approach under various conditions, comparative experiments were performed using the media of different viscosity and various positions of the plane on which the granulocytes were migrating. The cell shape and locomotion parameters estimated in various series of experiments indicate that the method may be generally useful and is able to detect not only major features of cell shape and movement, but also their relatively slight variations. The experiments performed in basic (typical) conditions revealed that the main axis of the majority of cells (about 60%) does not deviate from the global direction of migration by an angle greater than 30 degrees; about 10% of cells move with the main axis perpendicular to this direction. The broader frontal part of granulocytes is directed forward with regard to the global movement direction in 58% of cells, whereas 28% of the cells move with the tail pointing forward. The results of joint analysis of the cell shape and motion have confirmed statistically some well known features of migrating granulocytes.(ABSTRACT TRUNCATED AT 250 WORDS)

Adhesive and motile properties of Lewis lung carcinoma LL2 lines.

The cell substrate adhesion of the Lewis lung carcinoma in vitro maintained sublines (LL2 basic line, WGA-resistant LL2-8, and Aleuria aurantia-resistant LL2-AAA) has been studied by a hydrodynamic method using various shearing forces generated by the medium flow. The force of adhesion of the LL2 cells is about 10(-12) N to 10(-11) N with statistically significant differences between various sublines: it is the highest for LL2-AAA cells, intermediate for LL2 cells and the smallest for LL2-8 cells. In another series of experiments the distribution of the number of single cells and multicellular aggregates in the suspensions of LL2 cells together with the effect of gravitational sedimentation were examined. When the LL2 cells are incubated in 37 degrees C they display active motile behaviour which consists in forming cell-surface extensions of various shapes and duration (from a few seconds to several minutes and more). The displacement of the whole cells (locomotion) has not been observed. The results of the study on adhesion and motility of LL2 cells are discussed from the point of view of their metastatic properties, cell-membrane structure and mechanisms of malignant invasion.