Premium
PHOSPHATE METABOLISM IN BLUE‐GREEN ALGAE. II. CHANGES IN PHOSPHATE DISTRIBUTION DURING STARVATION AND THE “POLYPHOSPHATE OVERPLUS” PHENOMENON IN PLECTONEMA BORYANUM
Author(s) -
SickoGoad Linda,
Jensen Thomas E.
Publication year - 1976
Publication title -
american journal of botany
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.218
H-Index - 151
eISSN - 1537-2197
pISSN - 0002-9122
DOI - 10.1002/j.1537-2197.1976.tb11800.x
Subject(s) - polyphosphate , phosphate , phosphorus , algae , biology , metabolism , biochemistry , cell wall , botany , chemistry , organic chemistry
Physiological aspects of phosphate utilization by the blue‐green alga Plectonema boryanum were studied. It was found that the external phosphate concentration influenced the distribution of phosphorus‐containing compounds in the cell. Culturing the alga in concentrations of 10, 100, and 1000 mg PO 4 /l resulted in increases in the level of acid‐soluble and acid‐insoluble polyphosphates. The values reported for 100 and 1000 mg PO 4 /l were the same, indicating that the cells were able to assimilate and utilize only fixed amounts of phosphates. The total phosphorus value for these cells was calculated to be 6.5 μg P per 10 6 cells. Culturing the alga in 1 mg PO 4 /l led to a decrease in phosphate concentration of all cell fractions. Cells grown in the absence of phosphate for 5 days had total cell phosphorus levels of 0.76 μg P per 10 6 cells. Cells in culture for two months or longer were found to have total cell phosphorus levels of 0.73 μg P per 10 6 cells. This was determined to be the minimum cell phosphorus level limiting growth. Transfer of cells from either culture condition to a medium containing phosphate led to an “overplus” phenomenon. This overplus phenomenon was characterized by increases in all cellular phosphorus fractions. The most dramatic increase was found in both the acid‐soluble and acid‐insoluble polyphosphates. These fractions often increased by more than an order of magnitude. The greatest phosphate uptake occurred within 1 hr of transfer of phosphate‐starved cells into a medium containing a known amount of phosphate and is essentially complete at 4 hr. The total cell phosphorus levels for uptake never increased beyond 18.9 μg per 10 6 cells.