[Bilayer agar cell cultures for studying cellular growth factors]. / Metod dvusloinykh agarovykh kul'tur kletok dlia izucheniia kletochnykh faktorov rosta.

The method for biological testing of growth factors (GF) produced by transformed cells is described. The method is suitable for studying the ability of donor cells to release GF that stimulate colony formation of test-cells. Donor cells and test-cells are placed into different semisolid agar layers and separated by intermediate agar layer. The method provides a much more efficient testing of GF biological activity than the use of conditioned cultural fluids of transformed cells. It permits the assessment of GF dialyzation and the role of donor cell proliferation in the production of GF.

[Bacterial adsorption on cultivated mammalian cells in conditions of mixed infection]. / Izuchenie adsorptsii bakterii na kul'tiviruemykh kletkakh mlekopitaiushchikh v usloviiakh smeshannoi infektsii.

The method based on the use of 3H-labeled bacteria was applied to study the relationship between the magnitude of uropathogenic E. coli strain adsorption on mammalian cells in vitro and preinfection of the latter ones with virus. The presence of measles virus in cell culture raised the adsorption level of bacteria. Meanwhile oncoviruses did not alter the adsorption level. The possibility of generalized alterations of the cell surface by virus infection is discussed.

[Biological properties of the Rous sarcoma virus isolated from transformed hamster cells]. / Biologicheskie svoistva virusa sarkomy Rausa, vydelennogo iz transformirovannykh kletok khomiachka.

Rous sarcoma virus (RSV) isolated from virogenic transformed hamster cells differed from the original Schmidt-Ruppin strain used to inoculate hamster embryo fibroblasts in the capacity to effectively transform mammalian cells, to multiply in these cells, in the reduced reproductive activity in chicken cells. These altered properties were relatively stable since they were retained in the first virus passages in chickens.

[Production of noninfectious virions of the Rous sarcoma virus by virogenic hamster cells]. / Produktsiia neinfektsionnykh virionov virusa sarkomy Rausa virogennymi khomiachkovymi kletkami.

Noninfectious virions morphologically identical with avian type C virus virions were produced in Rous sarcoma virus-transformed virogenic hamster cells. The population of the virions contained the major internal protein of avian oncornavirus. It is assumed that production of defective RSV virions occurred in the cells. The major internal protein of avian oncornaviruses was found to be incorporated into the virions containing in their membrane interspecies antigens of hamster oncornavirus produced spontaneously in the system under study. Thus, phenotypic mixing of avian and animal type C viruses in mammalian cells has first been observed.

[Characteristics of the type C virus produced by Rous sarcoma virus-transformed hamster cells]. / Kharakteristika virusa tipa C, produtsiruemogo khomiachkovymi kletkami, trasformirovannymi virusom sarkomy Rausa.

Production of hamster type C virus in Rous sarcoma virus-transformed hamster cells is described. This virus preparation was shown to contain the antigen of the major inner protein of avian type C viruses (p27). The population of virions produced by such cells consists of either of virions of two types (99%--99.9% virions type C of hamster and 0.1%--1% virions the core capsule of which is formed from Rous sarcoma virus p 27) or of virions phenotypically mixed with regard to the major inner protein. The latter possibility seems less likely.

[Relationship between Rous sarcoma virus production in golden hamster cells and the cell cycle]. / Sviaz' mezhdu produktsiei virusa sarkomy Rausa v kletkakh zolotistogo khomiachka i kletochnym tsiklom.

The axon terminals of neurosecretory cells, containing elementary granules of neurosecretory materials, have been described on the basis of light and electron microscopy. No allochthonous neurosecretory elements were found in the sinus gland. The discharge of the granules from some terminals of the sinus gland occur with the changed salinity of the environment. There is a great difference in the structure of the sinus gland when salinity is changed. The structure of the sinus gland and its modification under experimental conditions indicate a possibility of neurohormonal regulation of the hydromineral balance.

[Alterations of Rous virus and polyoma virus during their synthesis in the cells of unnatural hosts]. / Izmenenie virusa Rausa i virusa poliomy v protsesse ikh sinteza v kletkakh neprirodnykh khoziaev.

The line of human embryo fibroblasts transformed by Rous sarcoma virus (strain Schmidt-Ruppin) contained and produced Rous sarcoma virus; this was shown by the complement fixation test, immunofluorescent test, electron microscopy and labelling with 3H-uridine peak in sucrose gradient. Biological properties of the new synthesized virus differed from that of the parent Schmidt-Ruppin strain; the range of the sensitive cells and the protein envelope antigens altered in particular. Analogous results by the change of the viral biological properties produced in the unnatural host tissue were obtained for polioma virus synthesized in the human embryo fibroblasts transformed by this virus.