| Abstract: | Normal Paramecium tetraurelia cells stained with fluorescein-conjugated folate show intense fluorescence that can be reduced to near background autofluorescence with excess K2-folate, but not with excess KCl. Mutant d4–534, which is not attracted to folate and does not specifically bind 3H-folate, shows reduced fluorescence when stained. This method of monitoring specific folate binding to cells can be adapted to a microscale for rapid screening of clones since cells are routinely fixed and stained in microtiter wells. |
