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
121
I I I .
S Y N T H E T I C M E D I A IN R E L A T I O N TO C E L L S
A N D T H E I R T O T A L E N V I R O N M E N T
A. A D A P T A T I O N OF CELLS T O , A N D S T A B I L I T Y OF
CELL STRAINS IN, S Y N T H E T I C M E D I A
A distinction is made between primary cultures, made from tissues
isolated directly from the organism, and established cell lines, which
have been maintained for a number of serial passages and are presumed
to be capable of transfer in perpetuity. It is a fact of common experience
that primary cultures can, under suitable conditions, be maintained
for periods of up to several months, but that only in a certain proportion of trials can repeated serial passages be made from them.
This fact has usually been explained in terms of an "adaptation" of
the cells to growth in vitro. Analogously, cultures maintained in serial
passage in biological media can often, but not at every attempt, be
transferred directly to maintenance in synthetic media. This also has
usually been attributed to an "adaptation" to the synthetic medium.
McQuilkin et al. (1957), who adapted N C T C clone 929 (strain-L)
cells to the defined medium N C T C 109, adopted fairly rigorous criteria
of successful adaptation, namely: (1) cessation of recognizable cellular
degeneration; (2) attainment of a relatively rapid proliferation rate,
allowing weekly serial subculture; and (3) survival for a minimum of
100 days and at least 10 transfer generations. The original adaptation,
which produced N C T C strain 2071, required about 6 months of careful
ad hoc treatment to bring the cultures through the "critical period"
into a condition in which they could be placed on a routine regimen.
In 56 other attempts to adapt these cells to N C T C 109, 42 failed and
4 series were lost in laboratory accidents. In the 10 successful adaptations,
technical improvements had reduced the "critical periods", even of
those with the most severe adaptational difficulties, to the range of
4-21 weeks. Once adapted to defined media, some, but not all, cell
There are, in short, no easy rules to guide him who aspires to design
a medium for the maintenance, growth or differentiation of a particular
tissue. He must build upon the experience of others. The whole of our
knowledge of enzymology, intermediary metabolism, endocrinology;
of synthetic and degradative pathways at all levels from the microsome
to the whole animal; of physico-chemical states and systems as they
apply to cells, surfaces and solutions; all these may be relevant to the
problem and should be drawn upon in any rational approach to synthetic medium formulation.
121
I I I .
S Y N T H E T I C M E D I A IN R E L A T I O N TO C E L L S
A N D T H E I R T O T A L E N V I R O N M E N T
A. A D A P T A T I O N OF CELLS T O , A N D S T A B I L I T Y OF
CELL STRAINS IN, S Y N T H E T I C M E D I A
A distinction is made between primary cultures, made from tissues
isolated directly from the organism, and established cell lines, which
have been maintained for a number of serial passages and are presumed
to be capable of transfer in perpetuity. It is a fact of common experience
that primary cultures can, under suitable conditions, be maintained
for periods of up to several months, but that only in a certain proportion of trials can repeated serial passages be made from them.
This fact has usually been explained in terms of an "adaptation" of
the cells to growth in vitro. Analogously, cultures maintained in serial
passage in biological media can often, but not at every attempt, be
transferred directly to maintenance in synthetic media. This also has
usually been attributed to an "adaptation" to the synthetic medium.
McQuilkin et al. (1957), who adapted N C T C clone 929 (strain-L)
cells to the defined medium N C T C 109, adopted fairly rigorous criteria
of successful adaptation, namely: (1) cessation of recognizable cellular
degeneration; (2) attainment of a relatively rapid proliferation rate,
allowing weekly serial subculture; and (3) survival for a minimum of
100 days and at least 10 transfer generations. The original adaptation,
which produced N C T C strain 2071, required about 6 months of careful
ad hoc treatment to bring the cultures through the "critical period"
into a condition in which they could be placed on a routine regimen.
In 56 other attempts to adapt these cells to N C T C 109, 42 failed and
4 series were lost in laboratory accidents. In the 10 successful adaptations,
technical improvements had reduced the "critical periods", even of
those with the most severe adaptational difficulties, to the range of
4-21 weeks. Once adapted to defined media, some, but not all, cell
There are, in short, no easy rules to guide him who aspires to design
a medium for the maintenance, growth or differentiation of a particular
tissue. He must build upon the experience of others. The whole of our
knowledge of enzymology, intermediary metabolism, endocrinology;
of synthetic and degradative pathways at all levels from the microsome
to the whole animal; of physico-chemical states and systems as they
apply to cells, surfaces and solutions; all these may be relevant to the
problem and should be drawn upon in any rational approach to synthetic medium formulation.