The Journal of Medical Microbiology, Vol 12, Issue 1 83-97, Copyright © 1979 by Society for General Microbiology
The effect of 5-fluorocytosine on the blastospores and hyphae of Candida albicans
A. Polak and W. H. Wain
In Candida albicans the continued increase in dry weight, in cell volume
and in hyphal length during 5FC treatment is mainly due to increased amount
of carbohydrate despite the decreased amounts of nucleic acids.
Incorporation studies with 32PO4 (for RNA) in C. albicans and with
3H-thymidine-monophosphate (for DNA) in a thymidine-utilising strain of
Saccharomyces cerevisiae have shown that the decreased amounts of nucleic
acids were due to an inhibition of synthesis of RNA and DNA by 5FC.
Nuclear-staining techniques on the hyphal phase of C. albicans showed that
5FC inhibits nuclear division. The changes in amounts of protein during 5FC
treatment do not wholly explain the changes in cell size although
14C-histidine incorporation experiments showed that protein synthesis
continued in the presence of 5FC. 14C-glucose incorporation in the presence
of 5FC showed an initial accelerated synthesis of carbohydrate with a
maintained level of synthesis after 16 h. This abnormal pattern of
synthesis correlates with the increase in amount of carbohydrate and in
cell size and hyphal elongation. 5FC inhibits DNA synthesis, and all
manifestations of unbalanced growth that culminate in the cell volume
changes appear to be a consequence of that inhibition.
