126
C H A R I T Y W A Y M O U T H
At present, the conditions of stress attendant upon becoming established
in culture in synthetic media, as in supplemented media, probably
favour or produce cells with a different and perhaps more elaborate
nuclear apparatus than such somatic cells normally have in vivo. Only
further research will tell whether this is inevitable, or whether improvements in our understanding of cell nutrition will enable the
problem to be overcome and permit euploid cells to be regularly
cultivated.
One may conclude that there is an "adaptation" or selection of cells
for the synthetic media now in use, but that this state of affairs may be
largely a reflection of the imperfections of our knowledge, and consequently of our current media.
B. S Y N T H E T I C MEDIA FOR CELLS IN SUSPENSION
The plasma coagulum for a long time formed part of the accepted
medium for cell and tissue cultures, and was believed to be necessary
both for nutrition and for mechanical support. Only gradually was it
recognized that one of the main functions of plasma or serum was to
act as a "buffer", or protective cushion, to compensate for physical
and chemical inadequacies in the nutrient media. As the nutritional
requirements of cells were more fully met and more clearly defined,
and as supporting substrates other than plasma were introduced, the
need for this "cushion" has diminished but has not yet been entirely
and satisfactorily eliminated for cells grown in suspension. In stationary
cultures, where the cells grow relatively undisturbed and attached to
a substrate, conditions in the immediate micro-environment surrounding the cells are largely created by the cells themselves. Cells which
grow well in monolayer cultures in a fully synthetic medium normally
do not succeed in the same medium in suspension, agitation revealing
inadequacies which can only partly be overcome by more rigorous
control of the macro-environment. Successful suspension cultures still
for the most part depend on supplementation with 5-20 % serum,
though substitution of supposedly inert proteins, or of protective, nonmetabolizable, macromolecular materials (dextran, polyvinylpyrrolidone, methyl cellulose) can partly replace serum. Bryant et al. (1960)
were able to reduce, but not eliminate, serum for the growth of N C T C
clone 929 cells in medium N C T C 109, by addition of 0-1 °/o of 4000
CPS methylcellulose, and Swim and Parker (1960) grew uterine
fibroblasts in suspension in a serum-supplemented synthetic medium
in the presence of the adjuvant Pluronic F 68. Kuchler, Marlowe and
Merchant (1960) obtained successful growth in medium 199 supplemented with 0-5°/o peptone and 15 CPS methylcellulose over a wide
C H A R I T Y W A Y M O U T H
At present, the conditions of stress attendant upon becoming established
in culture in synthetic media, as in supplemented media, probably
favour or produce cells with a different and perhaps more elaborate
nuclear apparatus than such somatic cells normally have in vivo. Only
further research will tell whether this is inevitable, or whether improvements in our understanding of cell nutrition will enable the
problem to be overcome and permit euploid cells to be regularly
cultivated.
One may conclude that there is an "adaptation" or selection of cells
for the synthetic media now in use, but that this state of affairs may be
largely a reflection of the imperfections of our knowledge, and consequently of our current media.
B. S Y N T H E T I C MEDIA FOR CELLS IN SUSPENSION
The plasma coagulum for a long time formed part of the accepted
medium for cell and tissue cultures, and was believed to be necessary
both for nutrition and for mechanical support. Only gradually was it
recognized that one of the main functions of plasma or serum was to
act as a "buffer", or protective cushion, to compensate for physical
and chemical inadequacies in the nutrient media. As the nutritional
requirements of cells were more fully met and more clearly defined,
and as supporting substrates other than plasma were introduced, the
need for this "cushion" has diminished but has not yet been entirely
and satisfactorily eliminated for cells grown in suspension. In stationary
cultures, where the cells grow relatively undisturbed and attached to
a substrate, conditions in the immediate micro-environment surrounding the cells are largely created by the cells themselves. Cells which
grow well in monolayer cultures in a fully synthetic medium normally
do not succeed in the same medium in suspension, agitation revealing
inadequacies which can only partly be overcome by more rigorous
control of the macro-environment. Successful suspension cultures still
for the most part depend on supplementation with 5-20 % serum,
though substitution of supposedly inert proteins, or of protective, nonmetabolizable, macromolecular materials (dextran, polyvinylpyrrolidone, methyl cellulose) can partly replace serum. Bryant et al. (1960)
were able to reduce, but not eliminate, serum for the growth of N C T C
clone 929 cells in medium N C T C 109, by addition of 0-1 °/o of 4000
CPS methylcellulose, and Swim and Parker (1960) grew uterine
fibroblasts in suspension in a serum-supplemented synthetic medium
in the presence of the adjuvant Pluronic F 68. Kuchler, Marlowe and
Merchant (1960) obtained successful growth in medium 199 supplemented with 0-5°/o peptone and 15 CPS methylcellulose over a wide