scholarly journals LATENT VIRAL INFECTION OF CELLS IN TISSUE CULTURE

1961 ◽  
Vol 113 (2) ◽  
pp. 271-281 ◽  
Author(s):  
John P. Bader ◽  
Herbert R. Morgan

A study of the metabolic requirements for the growth of psittacosis virus in L cells has been extended to the water-soluble vitamins. In a system in which a balanced salt solution was used to deplete the cells of their vitamin constituents, only thiamine was essential for psittacosis virus production. Extended depletion of cells with media deficient in specific vitamins demonstrated that pantothenate, niacin (niacinamide), pyridoxine (pyridoxal), and choline, in addition to thiamine, were essential for maximal growth of psittacosis virus. No requirement for biotin, inositol, folic acid, or riboflavin was demonstrated, although the possibility of incomplete vitamin depletion of the cells has not been eliminated. In most cases in which a specific vitamin requirement was shown the decreased yield of virus was correlated with a delay in the cytopathic effects produced in the cell cultures by psittacosis virus.

1957 ◽  
Vol 106 (1) ◽  
pp. 39-44 ◽  
Author(s):  
Herbert R. Morgan ◽  
John P. Bader

By maintaining L cells in a balanced salt solution of inorganic salts and glucose (BSS) for 2 days or more, they are rendered incapable of supporting the growth of psittacosis virus (6BC), though it infects such cells and is present intracellularly for as long as 3 days in a non-infectious phase. The addition of an enriched medium to such a culture of cells at any time up to 4 days after infection results in the appearance of infectious virus within these cells, which multiplies and is released from the cells, providing the entire period of exposure of such cells to the BSS does not exceed 6 days, following which the cells die. A latent infection with psittacosis virus in a non-infectious phase has been established in a pure line of cells which possess properties of malignancy.


1954 ◽  
Vol 32 (1) ◽  
pp. 306-318
Author(s):  
Raymond C. Parker ◽  
George M. Healy ◽  
Dorothy C. Fisher

The replicate culture assay procedures of Earle and his associates have been adapted for use in evaluating the effectiveness of synthetic media. For this purpose, use has also been made of Earle's L strain mouse cells. Washed and continuously stirred suspensions of these or similar strains of cells may be dispensed, with reasonable assurance of uniformity, into a series of replicate cultures, the number depending on the volume of the suspension and the capacity and effectiveness of the stirring and dispensing unit. For use with synthetic media, the original procedures for the preparation and care of the replicate cultures and for their subsequent treatment for the counting of isolated, stained nuclei have been modified considerably. This paper describes the procedures that were finally adopted and also describes a relatively simple screening procedure in which washed cell suspensions may be used to advantage in making preliminary assays of synthetic media and in testing the relative toxicity or growth stimulating effects of substances added to, or derived from, natural media.


1954 ◽  
Vol 32 (3) ◽  
pp. 306-318 ◽  
Author(s):  
Raymond C. Parker ◽  
George M. Healy ◽  
Dorothy C. Fisher

The replicate culture assay procedures of Earle and his associates have been adapted for use in evaluating the effectiveness of synthetic media. For this purpose, use has also been made of Earle's L strain mouse cells. Washed and continuously stirred suspensions of these or similar strains of cells may be dispensed, with reasonable assurance of uniformity, into a series of replicate cultures, the number depending on the volume of the suspension and the capacity and effectiveness of the stirring and dispensing unit. For use with synthetic media, the original procedures for the preparation and care of the replicate cultures and for their subsequent treatment for the counting of isolated, stained nuclei have been modified considerably. This paper describes the procedures that were finally adopted and also describes a relatively simple screening procedure in which washed cell suspensions may be used to advantage in making preliminary assays of synthetic media and in testing the relative toxicity or growth stimulating effects of substances added to, or derived from, natural media.


1967 ◽  
Vol 2 (4) ◽  
pp. 545-555
Author(s):  
M. J. GRIFFIN ◽  
R. P. COX

The mechanisms of substrate induction and L-cyst(e)ine repression of alkaline phosphatase were studied in tissue culture using an established African green monkey kidney cell line (BS-C-I). L-Cyst(e)ine repression and substrate induction are mutually antagonistic. Evidence is presented which suggests that the increase in alkaline phosphatase levels induced by mono-phosphate esters may in part be due to protection of the enzyme from cellular degradation, while L-cyst(e)ine is believed to act either by repressing the synthesis of the enzyme or by selectively increasing its catabolism.


Author(s):  
CHARLES V. BENTON ◽  
ROGER W. JOHNSON ◽  
ALBERT PERRY ◽  
W.I. JONES ◽  
GEORGE P. SHIBLEY

2000 ◽  
Vol 74 (3) ◽  
pp. 203-208 ◽  
Author(s):  
K. Buchmann ◽  
C.V. Nielsen ◽  
J. Bresciani

AbstractSkin responses of fish to various parasites have been shown to involve various immunologically competent cells producing factors which guide the reactions of epithelial cells. However, the present study has demonstrated that a monoculture of epithelial cells has the ability to encapsulate and partially degrade ectoparasites without involvement of leukocytes. The ectoparasitic monogeneanGyrodactylus derjavini was kept on a monolayer of Epithelioma Papulosum Cyprini (EPC) cells in 24-well multidishes supplied with tissue culture medium. Gyrodactylus derjavini did not reproduce but survived an incubation period of up to139 h in the system. Due to sterile conditions, dead gyrodactylids were not subjected to microbial degradation and remained intact for several weeks. However, at 40 days G. derjavini was overgrown by EPC-cells and became partly degraded during the following 15 days. Analysis of enzyme reactivity in EPC-cells showed reactions for ten enzymes including esterases, amidases, phosphatases and phosphohydrolases. No marked differences for the ten enzymes between cell cultures with and without the ectoparasites were found but it cannot be excluded that some of these enzymes took part in parasite degradation. The study showed the in vitro capability of epithelial cells to interact, encapsulate and degrade G. derjavini without the involvement of leukocytes. This response probably is non-specific and will not exclude that various immunocompetent cells and their products normally optimize and accelerate elimination of invading parasites in vivo.


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