372
J. T. DINGLE AND M. WEBB
methylpentose (fucose) and 15-9% neuraminic acid. The presence of
keratosulphate has been demonstrated in calf bone (Meyer et al., 1956)
and inferred in the vertebrae ofthe 15-day embryonic chick (Lash and
Whitehouse, 1960).
It is unfortunate that greater use has not been made of embryonic
bone rudiments in organ culture, since this system seems promising
in the study of the relationship between the compositions and contents
of mucopolysaccharides and calcification. At present, although acid
mucopolysaccharides are assumed to be essential for calcification,
little is known about the function of these compounds in this process.
In animal experiments, injected
3 5
S 0 4
2 - is found to be concentrated
in bones in areas of active growth (Dziewiatkowski, 1951; Engfeldt,
Engstrom and Bostrom, 1954; Engfeldt and Hjertquist, 1954), whilst
Kent, Jowsey, Steddon, Oliver and Vaughan (1956), for example, in
a histological, autoradiographical and biochemical study of
3 5
S 0 4
2 -
incorporation into rabbit bone, obtained results consistent with the
hypothesis that two main series of biochemical processes operate
during calcification: (1) the synthesis of a sulphated organic matrix,
chondroitin sulphate, or closely allied substance; (2) the deposition
of inorganic ions in the ionic environment provided by the sulphated
mucopolysaccharides.
The work reported so far shows that acid mucopolysaccharides are
produced in culture by tissues from various sources. In summary,
tissue culture studies such as those of Grossfeld et al. (1957), Gaines
(1960) and Grossfeld (1961) implicate the synthetic activity of the
fibroblasts as the source of mucopolysaccharides. This has been confirmed with cultures of isolated fibroblasts by the work of Castor
(1957) and Morris (1960); in contrast HeLa cells, for example, do not
synthesize mucopolysaccharides (Lazzarini and Weissmann, 1960, but
cf. Kimura, 1961). Berenson et al. (1958) conclude that the embryonic
mesenchymal cell, the fibroblast, is the source of all known mucopolysaccharides, but Moore and Schoenberg (1959) consider that
endothelial cells (of the umbilical cord) may participate in the production of chondroitin sulphate. Dorfman and Schiller (1958) regard
differentiation in the fibroblast to result in the elaboration of specific
polysaccharides, i.e. the secretion of chondroitin sulphate-A by the
chondroblasts, and of hyaluronic acid by the cells of the synovial
membrane.
4. The Effect of Culture Conditions on the Production of Mucopolysaccharides
Probably the most important factor in determining the rate of
mucopolysaccharide formation in culture is the composition of the
medium, since, as Morris (1960) has shown, there is a direct relationship
J. T. DINGLE AND M. WEBB
methylpentose (fucose) and 15-9% neuraminic acid. The presence of
keratosulphate has been demonstrated in calf bone (Meyer et al., 1956)
and inferred in the vertebrae ofthe 15-day embryonic chick (Lash and
Whitehouse, 1960).
It is unfortunate that greater use has not been made of embryonic
bone rudiments in organ culture, since this system seems promising
in the study of the relationship between the compositions and contents
of mucopolysaccharides and calcification. At present, although acid
mucopolysaccharides are assumed to be essential for calcification,
little is known about the function of these compounds in this process.
In animal experiments, injected
3 5
S 0 4
2 - is found to be concentrated
in bones in areas of active growth (Dziewiatkowski, 1951; Engfeldt,
Engstrom and Bostrom, 1954; Engfeldt and Hjertquist, 1954), whilst
Kent, Jowsey, Steddon, Oliver and Vaughan (1956), for example, in
a histological, autoradiographical and biochemical study of
3 5
S 0 4
2 -
incorporation into rabbit bone, obtained results consistent with the
hypothesis that two main series of biochemical processes operate
during calcification: (1) the synthesis of a sulphated organic matrix,
chondroitin sulphate, or closely allied substance; (2) the deposition
of inorganic ions in the ionic environment provided by the sulphated
mucopolysaccharides.
The work reported so far shows that acid mucopolysaccharides are
produced in culture by tissues from various sources. In summary,
tissue culture studies such as those of Grossfeld et al. (1957), Gaines
(1960) and Grossfeld (1961) implicate the synthetic activity of the
fibroblasts as the source of mucopolysaccharides. This has been confirmed with cultures of isolated fibroblasts by the work of Castor
(1957) and Morris (1960); in contrast HeLa cells, for example, do not
synthesize mucopolysaccharides (Lazzarini and Weissmann, 1960, but
cf. Kimura, 1961). Berenson et al. (1958) conclude that the embryonic
mesenchymal cell, the fibroblast, is the source of all known mucopolysaccharides, but Moore and Schoenberg (1959) consider that
endothelial cells (of the umbilical cord) may participate in the production of chondroitin sulphate. Dorfman and Schiller (1958) regard
differentiation in the fibroblast to result in the elaboration of specific
polysaccharides, i.e. the secretion of chondroitin sulphate-A by the
chondroblasts, and of hyaluronic acid by the cells of the synovial
membrane.
4. The Effect of Culture Conditions on the Production of Mucopolysaccharides
Probably the most important factor in determining the rate of
mucopolysaccharide formation in culture is the composition of the
medium, since, as Morris (1960) has shown, there is a direct relationship