| Strains bearing disruption of genes encoding other 5 ATPase subunits ( VMA 1 , VMA 2 , VMA 3 , and VMA 4 ) fail to grow on media supplemented with 100 mM CaCl 2 or 4 mM ZnCl 2 , media buffered to pH 7 . 5 , or media with a glycerol carbon source . ^^^ On the same types of media only a delta vph 1 delta stv 1 double disruption mutant has growth phenotypes equivalent to strains bearing a single disruption of the VMA 1 , VMA 2 , VMA 3 , and VMA 4 genes ; a delta vph 1 strain has only moderate growth inhibition while a delta stv 1 strain has wild type growth on the conditions listed above . ^^^ |