3. C O N S T R U C T I O N A N D USE OF S Y N T H E T I C M E D I A
103
supplementing synthetic media with biological media. Historically,
the emphasis changed gradually and, as defined media became more
and more complete, one could refer to the quantitatively less and less
important biological media as supplements to the synthetic medium.
During the period of development, the matter was largely one of
terminology and of the relative importance which individual investigators attached to the respective parts. When plasma, serum and tissue
extracts were the foundation of all tissue-culture media, and little was
understood of their composition or functions, Tyrode's or Pannett and
Compton's solutions were thought of as inert diluents rather than as
true nutrients. Baker (1929) and Vogelaar and Erlichman (1933) were
among the first to attempt to give more than a diluent role to their
synthetic or semi-synthetic supplements, and to show that a real
replacement of certain of the components of the biological media was
possible.
Still further progress in this direction was made by Fischer (1941,
1948) and his collaborators, who adopted the technique of depleting
the natural fluids of low molecular weight substances by dialysis, and
systematically replacing them with known mixtures of biologically
active nutrients. In this way the importance, in particular, of amino
acids was clearly established.
The gradual replacement of more and more of the biological material
by chemically defined solutions has led to defined media which require
no supplements at all. More courage might well be displayed in applying the present-day synthetic media, or at least the principles which they
represent, to the nutritional problems of a wider range of cells and tissues.
It is unfortunate that the literature contains many references to work
in which complicated synthetic media (e.g. Medium 199 or N C T C 109)
are used quite uncritically as supplements to media which are for the
most part biological. One suspects that a simple salt solution would
sometimes do just as well for the purpose.
D. B I O L O G I C A L M E D I A AS S U P P L E M E N T S TO
S Y N T H E T I C M E D I A
The apparent need of most cells for small amounts of extraneous
protein, in an otherwise protein-free environment, has proved very
intriguing. As adumbrated in the chapter on methods, several specific
proteins (Lieberman and Ove, 1957, 1958, 1959; Fisher, Puck and
Sato, 1958; Weiss, 1959a, b ) , notably those from foetal serum, or
proteins in general, have been demonstrated or supposed to promote
attachment of cells to substrates or to protect cells from an unfavourable
environment (e.g. Billen and Debrunner, 1960). The evidence has not
103
supplementing synthetic media with biological media. Historically,
the emphasis changed gradually and, as defined media became more
and more complete, one could refer to the quantitatively less and less
important biological media as supplements to the synthetic medium.
During the period of development, the matter was largely one of
terminology and of the relative importance which individual investigators attached to the respective parts. When plasma, serum and tissue
extracts were the foundation of all tissue-culture media, and little was
understood of their composition or functions, Tyrode's or Pannett and
Compton's solutions were thought of as inert diluents rather than as
true nutrients. Baker (1929) and Vogelaar and Erlichman (1933) were
among the first to attempt to give more than a diluent role to their
synthetic or semi-synthetic supplements, and to show that a real
replacement of certain of the components of the biological media was
possible.
Still further progress in this direction was made by Fischer (1941,
1948) and his collaborators, who adopted the technique of depleting
the natural fluids of low molecular weight substances by dialysis, and
systematically replacing them with known mixtures of biologically
active nutrients. In this way the importance, in particular, of amino
acids was clearly established.
The gradual replacement of more and more of the biological material
by chemically defined solutions has led to defined media which require
no supplements at all. More courage might well be displayed in applying the present-day synthetic media, or at least the principles which they
represent, to the nutritional problems of a wider range of cells and tissues.
It is unfortunate that the literature contains many references to work
in which complicated synthetic media (e.g. Medium 199 or N C T C 109)
are used quite uncritically as supplements to media which are for the
most part biological. One suspects that a simple salt solution would
sometimes do just as well for the purpose.
D. B I O L O G I C A L M E D I A AS S U P P L E M E N T S TO
S Y N T H E T I C M E D I A
The apparent need of most cells for small amounts of extraneous
protein, in an otherwise protein-free environment, has proved very
intriguing. As adumbrated in the chapter on methods, several specific
proteins (Lieberman and Ove, 1957, 1958, 1959; Fisher, Puck and
Sato, 1958; Weiss, 1959a, b ) , notably those from foetal serum, or
proteins in general, have been demonstrated or supposed to promote
attachment of cells to substrates or to protect cells from an unfavourable
environment (e.g. Billen and Debrunner, 1960). The evidence has not