1 1 . M U C O P O L Y S A C C H A R I D E S IN T I S S U E C U L T U R E
375
C. M U C O P O L Y S A C C H A R I D E S A N D T H E C E L L S U R F A C E
Most investigations of the production of acid mucopolysaccharides
by cells in tissue culture have been concerned with analyses of the
material liberated into the culture medium, and few experiments have
been directed to an assessment of the relationship between hyaluronic
acid, or other mucopolysaccharides, and the cell itself. From a
limited number of experiments, Morris (1960) reported that a small
of lactic acid formation. It is possible that the fall in rate of production
may be associated with either deprivation of glucose, or reduction in
the p H of the medium. Both of these possibilities, however, are contrary
to the conclusions of Morris (1960), summarized in the preceding
section.
There are a number of conflicting reports of the ability of dispersed
cells in culture to produce acid mucopolysaccharides over long periods.
Castor (1959) has described the continued production of hyaluronic
acid by human synovial cells. Grossfeld (1959) and Morris and Godman
(1960) have also shown that under suitable cultural conditions, fibroblasts from a variety of sources may retain the ability to produce acid
mucopolysaccharides for some years. Other authors (Kling et al.,
1955; Hedberg and Moritz, 1958) conclude that the capacity for acid
mucopolysaccharide production may be lost during prolonged culture.
It has been suggested by Grossfeld (1959) that a decline in mucopolysaccharide production seen in replicate cultures of dermal fibroblasts
is due to a loss of differentiation, evidenced by the simultaneous development of a high glycolysis and a low respiration. A cessation of acid
mucopolysaccharide production was observed also by Daniel et al.
(1961) in long term cultures of rat dermal fibroblasts. These authors,
however, found that by repeated additions of small amounts of cobalt
chloride to the medium, the cells not only became "cobalt tolerant"
but also retained the ability to produce acid mucopolysaccharides,
even after termination of cobalt treatment. These cobalt-tolerant
cells showed increased glycolysis, lowered respiration and abnormal
cytology.
Kimura (1961) determined the production of hexosamine by Hela
and FL cells (the latter being a strain derived from the normal amnion
cell) and found the amount of the amino sugar liberated into the medium
to be correlated with the total amount of cells. The highest rate of
production, per cell, was in the earliest phase of the culture period.
The content of sialic acid in the medium, however, remained unchanged.
375
C. M U C O P O L Y S A C C H A R I D E S A N D T H E C E L L S U R F A C E
Most investigations of the production of acid mucopolysaccharides
by cells in tissue culture have been concerned with analyses of the
material liberated into the culture medium, and few experiments have
been directed to an assessment of the relationship between hyaluronic
acid, or other mucopolysaccharides, and the cell itself. From a
limited number of experiments, Morris (1960) reported that a small
of lactic acid formation. It is possible that the fall in rate of production
may be associated with either deprivation of glucose, or reduction in
the p H of the medium. Both of these possibilities, however, are contrary
to the conclusions of Morris (1960), summarized in the preceding
section.
There are a number of conflicting reports of the ability of dispersed
cells in culture to produce acid mucopolysaccharides over long periods.
Castor (1959) has described the continued production of hyaluronic
acid by human synovial cells. Grossfeld (1959) and Morris and Godman
(1960) have also shown that under suitable cultural conditions, fibroblasts from a variety of sources may retain the ability to produce acid
mucopolysaccharides for some years. Other authors (Kling et al.,
1955; Hedberg and Moritz, 1958) conclude that the capacity for acid
mucopolysaccharide production may be lost during prolonged culture.
It has been suggested by Grossfeld (1959) that a decline in mucopolysaccharide production seen in replicate cultures of dermal fibroblasts
is due to a loss of differentiation, evidenced by the simultaneous development of a high glycolysis and a low respiration. A cessation of acid
mucopolysaccharide production was observed also by Daniel et al.
(1961) in long term cultures of rat dermal fibroblasts. These authors,
however, found that by repeated additions of small amounts of cobalt
chloride to the medium, the cells not only became "cobalt tolerant"
but also retained the ability to produce acid mucopolysaccharides,
even after termination of cobalt treatment. These cobalt-tolerant
cells showed increased glycolysis, lowered respiration and abnormal
cytology.
Kimura (1961) determined the production of hexosamine by Hela
and FL cells (the latter being a strain derived from the normal amnion
cell) and found the amount of the amino sugar liberated into the medium
to be correlated with the total amount of cells. The highest rate of
production, per cell, was in the earliest phase of the culture period.
The content of sialic acid in the medium, however, remained unchanged.