The mineral composition of chlorella pyrenoidosa grown in culture media containing varying concentrations of calcium, magnesium, potassium, and sodium

Abstract

The inorganic composition of living cells is regulated by a selective a h -r p t i o n process which undoubtedly is intimately associated with metabolism. The mineral environment, however, may influence the absorption of electrolytes by effecting a shift in metabolism itself (Steward and Preston, '41), or, as recent data seem to indicate, by direct chemical interaction of environmental cations with cellular constituents. A systematic study of the relationship of the electrolytic environment to the chemical composition of living organisms reveals the degree to which the surrounding medium may determine the concentration of intra-cellular mineral elements.Chlorella pyrenoidosa is found in most naturally occurring bodies of fresh water. Consequently this unicellular algal cell can adjust to a considerable variation in its mineral environment. This paper reports a study of the extent to which the amount of calcium, magnesium, potassium, sodium and phosphorus in this plant cell varies as the concentration of the various cations in the culture medium are altered. MATERIALS AND METHODSThe original cultures of Chlorella pyrenoidosa were obtained in 1937 from the laboratory of C. B. Van Niel. The strain was isolated and identified by Dr. Robert Emerson.Pure stocks of Chlorella pyrenoidosa were maintained on washed agar slants enriched by Detmer's inorganic medium. For tests of purity of the stocks, streaks were made from time to time on agar slants containing, in addition to Detmer's medium, glucose and peptone added in concentrations of 2% and 0.5% respectively. On such a substrate bacterial or mold contaminants became apparent through their rapid overgrowth of the Chlorella. The mass culture method developed by Ketchum and Redfield ( '38) for marine diatoms has been further refined and adapted to the growth of Chlorella. The cultures are grown in large Pyrex bottles containing 10 or 12 liters of Detmer 's medium of the following composition :

The Absorption of Inorganic Ions by Chlorella pyrenoidosa.

“…In comparing the values reported in this paper with those of others it was noted that our values for calcium and iron agree with those found in the literature (8,11,13). Our values for phosphorus are, however, 10 to 100 times those reported by Scott (11,12,13), but they are within the range of 1 to 4 times those reported for bean plant leaves (3). No explanation, other than a difference in method, is immediately apparent for the difference between our results and those of Scott.…”

“…The procedure of a single wash of the cells with a solution of the nutrient under study was then arbitrarily adopted as one which would give most accurate values for elemental content within the cell structure. In comparing the values reported in this paper with those of others it was noted that our values for calcium and iron agree with those found in the literature (8,11,13). Our values for phosphorus are, however, 10 to 100 times those reported by Scott (11,12,13), but they are within the range of 1 to 4 times those reported for bean plant leaves (3).…”

“…Scott (11) has reported that the ratio of uptake of calcium and magnesium by Chlorella depends upon the ratio of these two elements in the nutrient solution. Scott (12) has also studied the behavior of phosphatedeficient cells during a restoration period when adequate phosphate was supplied to the nutrient medium.…”

Inhibitory Effects of Phytoplankton upon the Feeding of Daphnia Magna with Reference to Growth, Reproduction, and Survival

“…Algae were cultured in 10-liter batches in Pyrex jugs illuminated by water-cooled, immersed neon U-tubes and aerated with 5% C02, as described by Scott (1943). Smaller, 500-ml.…”

The effect of carbon on algal growth—Its relationship to eutrophication

“…Lake Tahoe, although perhaps experiencing some enrichment, is still one of the lesser productive natural water bodies in the world. Scott (1943), Spoehr and Milner (1949), Ketchum and Redfield (1949) Edmondson (1970) has presented the chemical and biological changes that occurred when secondary effluent was diverted from Lake Washington producing major changes in nutrient input. Approximately three years following the diversions, the lake has improved markedly as evidenced by the reduction in chlorophyll in surface phytoplankton and transparency of the lake.…”