Iron Deficiency and the Metabolism of Tetrahymena pyriformis*

Abstract

SYNOPSIS. An iron deficiency was noted for Tetrahymena grown in a proteose‐peptone‐yeast extract medium. Thus, the addition of an iron chelate and glucose was found to give consistent and luxuriant growth, whereas a number of other additives, including sodium acetate, an inorganic salt mixture lacking iron, and vitamins were found to be without influence on growth rate or cellular yield. Iron‐deficient cells showed a marked reduction of oxidative capacity when suspended in a non‐nutrient medium as well as when supplied with oxidizable substrates. A 1 hour incubation of iron‐deficient Tetrahymena with iron chelate restored oxidative capacity only when the cells were suspended in a nutrient (peptone) medium. Growth of Tetrahymena in media autoclaved with salts resulted in cells with a larger volume but with no increase in oxidative capacity. The addition of 2,4‐dinitrophenol elevated respiration of cells suspended in a non‐nutrient medium, and of iron deficient cells suspended in the growth medium, suggesting that this compound increases the availability of iron or iron containing compounds, or by‐passes the limiting steps. Respiratory quotients were lowered by an iron deficiency and elevated when the cells were grown in the presence of iron and glucose. This suggests more complete utilization of the carbohydrate, possibly due to the activity of a number of enzymes known to be iron‐containing metalloproteins that are required for oxidative glucose dissimilation.

Dual capacity for nutrient uptake in tetrahymena importance of the oral uptake system for Fe and Cu uptake

“…We have confirmed for strain GL and inbred strain D of syngen 1 CONNER and CLINE'S observation for strain W that 2% proteose peptone broth, even though it allows transplantable growth indefinitely, is nutritionally deficient for Tetrahymena (4). Fe corrects that deficiency.…”

Cholesterol Inhibition of Pentacyclic Triterpenoid Biosynthesis in Tetrahymena pyriformis*†

“…Axenic cultures of Tetrahymena pyriformis W were maintained in a proteose peptone-based culture fluid and the cells were harvested by methods described previously (8,9). When the ciliate was grown with a cholesterol supplementation, an ethanolic solution of cholesterol was dispersed aseptically into culture fluid that has been previously autoclaved and reheated to 80 C. After the mixture had been cooled to 28 C, the seed culture of ciliates was added.…”

“…Tetrahymanol' (mg/500 ml) (pg/108 cells) 8 junction with cholesterol there was an accumulation of label in region IX-X. Squalene could not be detected by iodine or phosphomolybdic acid visualization when this region was replated on Silica Gel G plates and developed with 100% petroleum ether.…”

Studies of Membrane Formation in Tetrahymena pyriformis. I. Rates of Phospholipid Biosynthesis*

“…Approximately 3 X 10' cells were added from a stock culture to a 500-ml erlenmeyer flask containing 200 ml of a medium composed of 2 % proteose peptone, 0.5% dextrose, 0 . 2 z yeast extract, and 2 ml of 9 mM Fe3+-EDTA complex (Conner and Cline, 1964). Aeration was provided by a 4.5-cm long magnetic stirring bar turning at 200 rpm, and the temperature was constant at 22".…”