[Effect of hyperthermia on protein synthesis in monolayer and suspension cultures of mouse L cells]. / Effekt gipertermii na sintez belkov v monosloinoi i suspenzionnoi kul'turakh kletok myshi L.

Changes in protein synthesis that occurred under the influence of heat shock (HS) in monolayer (L929) and suspension (LS) mouse cell cultures were studied. The rates of protein synthesis determined as 35S-methionine incorporations were seen reduced from the initial level up to 40-60 and 6-13% after HS at 42 and 44 degrees C, respectively. Simultaneously the rate of actin and tubulin syntheses decreased, the decrease being more pronounced in LS cells. According to electrophoresis and autoradiography data, after hyperthermia both the cell cultures were able to synthesize heat shock proteins (HSP), primarily HSP70. After a 40 min HS towards L929 and LS cells at 43 degrees C, the shares of their HSP70 bands in the total label loaded on the gel constituted, resp., 8.8 and 5.4%. The data suggest that L929 cells, with their synthetic activity lower than in LS cells, appear more resistant to HS and are able eventually to synthesize larger amounts of HSP70, compared to the latter.

[Actin and tubulin synthesis in monolayer and suspension cultures of murine L cells]. / Sintez aktina i tubulina v monosloinoi i suspenzionnoi kul'turakh kletok myshi L.

The rates of total protein, actin and tubulin synthesis were studied for monolayer (L-929) and suspension (LS) cultures of mouse L cell. Data on pulse 34S-label incorporation into the cellular protein pool show that LS characterized by a short cell cycle have, comparatively to L-929, higher rates of protein synthesis and phosphorylation. According to PAGE data, the level of actin and tubulin synthesis in suspension line exceeds that in monolayer one. The correlation between growth conditions, biosynthetic parameters and dynamics of cytoskeleton is discussed.

[Expression of heat-shock proteins in neuroblastoma cells differing genetically in thermal sensitivity]. / Ekspressiia belkov teplovogo shoka v kletkakh neiroblastomy, geneticheski razlichaiushchikhsia po termochuvstvitel'nosti.

Electrophoretic analysis of cell proteins of 3 mouse neuroblastoma strains differing in thermostability has shown that a distinctive feature of one of the strains (stable to the action of temperature at 44 degrees C) is the accumulation under normal conditions (37 degrees C) of heat shock protein with the molecular mass of 70 kD. Such accumulation of the specific protein does not take place in cells of the thermosensitive strain, stable to temperature of 40 degrees C.