9. P R O T E I N M E T A B O L I S M IN C U L T U R E
303
B. C O M P A R A T I V E U T I L I Z A T I O N
Pasieka, Morton and Morgan (1956) studied the amino-acid metabolism of explants of embryonic chick heart-tissue cultivated in a
chemically defined medium. In their experiments, variations in aminoacid content of the medium were followed by paper chromatography
and the changes observed were expressed on a semi-quantitative basis
as slight, moderate or marked. Utilization of amino acids was greatest
during the period from the fourteenth to the twenty-fifth day of cultivation when large quantities of cystine, lysine, histidine and arginine
were removed from the medium. At the end of the culture period
(twenty-fifth to thirty-sixth days), there was no marked increase in the
amino-acid content of the medium, despite the fact that nearly half
of the cells showed signs of degeneration and a considerable reduction
in cell number had occurred as a result of cell death and autolysis.
The authors concluded that cell degeneration and death were not
accompanied by a large outpouring of amino acids into the medium.
It is possible, however, that such a release of amino acids was undetected
since it may have been masked by the utilization of amino acids by
the surviving cells, so that the total balance was unchanged.
The same workers have made a comparable paper-chromatographic
study on explants of chick embryonic kidney and liver (Pasieka et al.,
1958). Cystine, histidine, arginine, tyrosine, tryptophan, valine, isoleucine and leucine were utilized, while serine, glycine, threonine, alanine
and methionine were produced as with the heart tissue. Uptake of
lysine, aspartic acid, glutamic acid, proline, hydroxyproline and
phenylalanine varied between the different cultures. Chick embryonic
kidney showed a pattern resembling that of chick embryonic liver
except that a moderate uptake of proline occurred and no accumulation
of aspartic or glutamic acids could be detected.
Glutamine was found to increase in the medium during cultivation
of freshly explanted heart, kidney and liver from the embryonic chick,
while established cell strains that were largely of malignant origin
caused a marked decrease in the concentration of glutamine in the
medium (Pasieka and Morgan, 1959; Morgan and Pasieka, 1960).
In a quantitative study, Sinclair and Leslie (1959) noted that glutamine
was extensively or entirely removed from the culture medium during
growth of a number of cell types that included both short-term cultures
of human foetal lung and kidney cells and also cell lines of malignant
origin.
The amino-acid utilization of freshly isolated cells from the breast
muscle of the embryonic chick has been studied quantitatively by
means of ion-exchange chromatography (Lucy and Rinaldini, 1959).
303
B. C O M P A R A T I V E U T I L I Z A T I O N
Pasieka, Morton and Morgan (1956) studied the amino-acid metabolism of explants of embryonic chick heart-tissue cultivated in a
chemically defined medium. In their experiments, variations in aminoacid content of the medium were followed by paper chromatography
and the changes observed were expressed on a semi-quantitative basis
as slight, moderate or marked. Utilization of amino acids was greatest
during the period from the fourteenth to the twenty-fifth day of cultivation when large quantities of cystine, lysine, histidine and arginine
were removed from the medium. At the end of the culture period
(twenty-fifth to thirty-sixth days), there was no marked increase in the
amino-acid content of the medium, despite the fact that nearly half
of the cells showed signs of degeneration and a considerable reduction
in cell number had occurred as a result of cell death and autolysis.
The authors concluded that cell degeneration and death were not
accompanied by a large outpouring of amino acids into the medium.
It is possible, however, that such a release of amino acids was undetected
since it may have been masked by the utilization of amino acids by
the surviving cells, so that the total balance was unchanged.
The same workers have made a comparable paper-chromatographic
study on explants of chick embryonic kidney and liver (Pasieka et al.,
1958). Cystine, histidine, arginine, tyrosine, tryptophan, valine, isoleucine and leucine were utilized, while serine, glycine, threonine, alanine
and methionine were produced as with the heart tissue. Uptake of
lysine, aspartic acid, glutamic acid, proline, hydroxyproline and
phenylalanine varied between the different cultures. Chick embryonic
kidney showed a pattern resembling that of chick embryonic liver
except that a moderate uptake of proline occurred and no accumulation
of aspartic or glutamic acids could be detected.
Glutamine was found to increase in the medium during cultivation
of freshly explanted heart, kidney and liver from the embryonic chick,
while established cell strains that were largely of malignant origin
caused a marked decrease in the concentration of glutamine in the
medium (Pasieka and Morgan, 1959; Morgan and Pasieka, 1960).
In a quantitative study, Sinclair and Leslie (1959) noted that glutamine
was extensively or entirely removed from the culture medium during
growth of a number of cell types that included both short-term cultures
of human foetal lung and kidney cells and also cell lines of malignant
origin.
The amino-acid utilization of freshly isolated cells from the breast
muscle of the embryonic chick has been studied quantitatively by
means of ion-exchange chromatography (Lucy and Rinaldini, 1959).