Abstract
Summary
1. A two thousand-fold increase in resistance to amethopterin has been induced in L. citrovorum. Since growth was slow at this high concentration of amethopterin, the culture was maintained on a medium with 400 times the concentration of amethopterin tolerated by the parent culture. 2. This amethopterin-fast variant has been maintained in the above medium for more than 5 months without any observed physiological or morphological changes.
Get full access to this article
View all access options for this article.