Abstract
Mycobacterium smegmatis required about 2 ug of Iron/ml and 0.4 ug of zinc/ml for full growth on Proskauer and Beck medium. If the concentration of either metal was decreased, growth slowed sooner than normally and the final yield was reduced. RNA (per g of insoluble N) fell at about the time of growth inhibition because of deficiencies of Fe, Zn, C or N, or of both C and N. RNA from metal-deficient cultures had a normal base composition. DNA (per g of N) increased when either C or N became deficient. In Zn deficiency there was no increase, and in Fe deficiency there was a slight fall. The bacteria decreased in size when C or N became deficient. The length of the bacteria increased several times during Fe deficiency and somewhat less in Zn deficiency. In Zn deficiency insoluble inorganic polyphosphate (per g of N) increased several-fold, suggesting that energy- and phosphate-us ing reactions were inhibited rather than respiration. In normal and in Fe deficient cultures the polyphosphate increase stopped after a short time, suggesting that energy-supplying reactions also were inhibited. In both metal deficiencies acid-labile acid-soluble phosphate (per g of N) fell about a day after growth inhibition, and acid-stable acid-soluble phosphate fell sooner. ATP (per g of N) fell in both normal and Fe deficient cultures at about the time of growth inhibition, suggesting a relative slowing of adenylic acid synthesis. In Zn-deficient cultures it remained high. The amount of pyridine nucleotides (per g of N) remained high in normal cultures. It fell early in Zn deficient and particularly in Fe-deficient cultures. Total lipids (per g of N) fell less in both metal-deficient cultures than in normal cultures, and phospholipids rose in metal deficiency. Insoluble N (per g dry wt.) rose slightly in normal and Fe-deficient cultures, and fell in Zn deficiency. Acid-soluble N (per g dry wt.) fell more rapidly than normal in both deficient cultures. In normal cultures coproporphyrin (per g of N) rose to a peak and then fell with increasing age. In N deficiency amounts were greatly increased. In early Zn deficiency amounts were higher, and in early Fe deficiency lower, than normal. At later stages amounts in both these cultures rose.