The specific amino acid requirements of a human carcinoma cell (Stain HeLa) in tissue culture

THE AMINO ACID REQUIREMENTS OF A PERMANENT STRAIN OF ALTERED UTERINE FIBROBLASTS (U12-705)

A permanent line of altered human fibroblasts, strain U12-705, was found to require arginine, cystine, glutamine, histidine, isoleucine, leucine, lysine, methionine, phenylalanine, tryptophan, tyrosine, and valine for growth in a defined medium supplemented with 2.5% (v/v) dialyzed chick embryo extract and 5% dialyzed horse serum. In the absence of any of the essential amino acids the cells not only fail to proliferate but undergo degenerative changes which increased with time. The omission of alanine, aspartic acid, glutamic acid, glycine, hydroxyproline, and proline either separately or collectively does not alter the rate of growth or result in changes in the appearance of the cells. Cysteine and glutathione are equally as effective as cystine in promoting the growth of U12-705. None of the D-enantiomorphs of the essential amino acids will effectively replace the corresponding L-isomer. Single D-amino acids are not inhibitory when added to the medium in 5 times the concentration of the L-amino acid. The minimum concentrations of essential amino acids which permit optimal proliferation under the conditions employed range from 0.005 to 0.5 mM. Essential amino acids with the exception of glutamine, isoleucine, leucine, threonine, and valine are toxic for U12-705 when employed at a concentration of 5 mM. Toxic manifestations vary with the amino acid and range from cytologic changes in the cells without a significant decrease in the growth rate to complete inhibition of growth and extensive cellular degeneration.

Growth characteristics of poliovirus in HeLa cells: nucleic acid metabolism

The RNA and DNA contents of the nucleus and cytoplasm of the HeLa cell were determined. The rates of incorporation of P(32) into the various nucleic acid fractions were established for the ordinary HeLa cell maintained under a set of standard conditions. The changes in the rates of incorporation of P(32) and in the amounts of RNA and DNA which occurred subsequent to infection with poliovirus were followed throughout the infectious cycle. These changes were correlated with the intracellular appearance of the newly formed virus. A net synthesis of RNA occurred in the cytoplasmic component of the cell. The increase was detectable 2 hours before the first appearance of demonstrable virus and reached a maximum (2.5 times normal) at 6 hours. Viral increase was not maximal before the 7th hour after infection.

The amino acid requirements of rabbit fibroblasts, strain RM3-56

Strain RM3-56 of rabbit fibroblasts was found to require arginine, cystine, glutamine, histidine, isoleucine, leucine, lysine, methionine, phenylalanine, serine, threonine, tryptophan, tyrosine, and valine for growth in a medium containing 2 per cent dialyzed serum as the only undefined component. The requirement for serine is less specific than that of the other 13 amino acids and it is partially replaced by glycine, or alanine, or by several combinations of so called accessory amino acids. The concentrations of essential amino acids which permit maximal proliferation range from 0.005 to 0.3 mM. Cystine, glutamine, lysine, tryptophan, tyrosine, valine are toxic at concentrations of 5 mM. The rate of proliferation of RM3-56 in a medium containing all 14 essential amino acids is increased significantly by the addition of alanine and to a lesser extent by the addition of aspartic and glutamic acids and glycine. A deficiency of cystine or glutamine results in cellular degeneration within 3 to 5 days, whereas the cells remain in good condition for 2 to 3 weeks in the absence of each of the remaining 12 essential amino acids. The results obtained with RM3-56 are compared with strains HeLa, L, and U12, whose amino acid requirements have been investigated under similar conditions.

The nutrition of animal tissues cultivated in vitro. IV. Amino acid requirements of chick embryonic heart fibroblasts

1. The amino acid requirements of freshly explanted chick embryonic heart tissues cultivated in completely synthetic media have been determined, employing a nutritional depletion technique. Arginine, histidine, lysine, tyrosine, tryptophan, phenylalanine, cystine, methionine, threonine, leucine, and valine were found to be essential. Serine, isoleucine, glycine, and glutamine were found to be non-essential. Glutamic acid, aspartic acid, alpha-alanine, proline, and hydroxyproline were found to be inhibitory in this test system. 2. A total amino acid level of approximately 100 mg. per cent was found to be optimal and DL-amino acids were found to be non-toxic, unless used in high concentrations. 3. A comparison has been made of the amino acid requirements of various types of tissue cultures, of the chick, and of man and certain differences in these requirements have been discussed.

[The antiviral action of threo-beta-phenylserine]

L-threo-phenylserine and esters of threo-phenylserine were the most active of a series of compounds tested against influenza A virus in tissue culture. Substitution of the beta-OH or alpha-NH(2) group abolished activity. The activity of phenylserine was reversed competitively by phenylalanine. Phenylserine did not act on free virus or on the adsorption of virus to host cells. It prevented virus growth if added during the first half of the latent period.Phenylalanine appears to be necessary for virus synthesis and can be supplied by phenylalanylglycine or glycylphenylalanine.Phenylserine had no significant activity against ectromelia infections in mice, even when the amino acid content of the livers had been depleted by starvation.

The nutrition of animal tissues cultivated in vitro. III. Use of a depletion technique for determining specific nutritional requirements

1. Cultivation of freshly explanted chick embryonic heart tissues in Hanks's salt solution for 3 to 4 days has been shown to create a general state of nutritional deficiency in the cultures. Provided the depletion is not prolonged beyond 4 days, the cultures subsequently revive and survive to a normal period in synthetic medium M 150. 2. Paper chromatographic studies on the culture medium have shown that the amino acid metabolism of the depleted cultures is restored to a normal pattern within a few days in medium M 150. 3. By the use of the nutritional deficiency technique, a coenzyme A requirement for this type of culture has been established. 4. The application of these findings to tissue cell nutrition and the possible hazards of using serum, or other uncharacterized additions, either to establish cultures, or as part of the experimental medium, are discussed.

The nutritional requirements for the propagation of poliomyelitis virus by the HeLa cell

Only minimal amounts of poliomyelitis virus were formed by HeLa cells placed in a medium free from glucose and glutamine, even if the medium contained an otherwise full complement of essential and non-essential amino acids, purines, pyrimidines, NB(4) (+), and serum protein. Conversely, within one log of the optimal yield of virus was formed by HeLa cells in a medium containing only glucose, glutamine, and salts, even if the cells had been starved in this medium for 12 hours prior to their inoculation. The presence of glucose alone caused an average 170-fold increase in viral output beyond the amounts formed by the glucose- and glutamine-depleted cells. The addition of glutamine alone caused an average 2000-fold increase; and the addition of both increased the viral formation 40,000-fold. Qualitatively similar results were obtained with unstarved cells, not previously depleted of glucose and glutamine. It follows that only a small proportion of HeLa cells are capable of forming virus unless either glucose or glutamine, or both, are present in the medium. The elaboration of virus was significantly delayed in media containing glucose but no glutamine. The absence of glucose and glutamine did not prevent the fixation of poliomyelitis virus by the cell. When these compounds were added to previously depleted cells even 6 hours after inoculation, and after the excess free virus had been removed by washing and by the addition of specific antiserum, normal amounts of virus were formed despite the degenerative changes caused by the previous glucose and glutamine deprivation. Possible functions of glucose and glutamine in the elaboration of virus are discussed in the text. Such factors other than glucose, glutamine, or salts (e.g. amino acids, purines, pyrimidines, vitamins, protein, or NH(4) (+)) as may be needed by HeLa cells for the propagation of poliomyelitis virus, need not be present in the medium and cannot be easily washed out of the cell. Even 12 hours' total deprivation of the cells in salt solution prior to inoculation only slightly decreased their virus-synthesizing capacity in a similarly deficient medium, provided only that adequate amounts of glucose and glutamine were retained.