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LUXURY PHOSPHATE UPTAKE AND VARIATION OF INTRACELLULAR METAL CONCENTRATIONS IN HETEROSIGMA AKASHIWO (RAPHIDOPHYCEAE) 1
Author(s) -
Watanabe MasatMaka,
Takamatsu Takejiro,
Kohata Kunio,
Kunugi Masayuki,
Kawashima Munetsugu,
Koyama Mutsuo
Publication year - 1989
Publication title -
journal of phycology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.85
H-Index - 127
eISSN - 1529-8817
pISSN - 0022-3646
DOI - 10.1111/j.1529-8817.1989.tb00247.x
Subject(s) - heterosigma akashiwo , intracellular , phosphate , biology , extracellular , polyphosphate , cell growth , cell , biochemistry , nuclear chemistry , biophysics , chemistry , nutrient , ecology , phytoplankton , algal bloom
The effectr of phosphate starvation and subsequent uptake on distribution and concentration of phosphate metabolic intermediates and metals were studied in Heterosigma akashiwo (Hada) Hada by 31 P‐NMR spectroscopy, neutron activation analysis and ESR spectroscopy. Excess orthophosphate (4.5 μM P i , as NaH 2 PO 4 ) added to a medium with P‐depleted H. akashiwo cells was rapidly taken up resulting in an increase in P cell quota (q p )from 68.2 to 99.6 fmol. cell‐ 1 in 2 h and to 156.3 fmol. cell‐ 1 in 6 h. After three days, q p approached about 190 fmol. cell −1 . Polyphosphate (PP i ) rapidly increased from 0 to 11.4 fmol· cell −1 in 2 h and to 24.7 fmol·cell −1 in 6 h. Diel variation of cell quota indicated that cellular P i increase was synchronized with cellular PP i decrease and vice versa. The average chain length of PP i increased from ca. 0 to ca. 10.2 phosphate residues in 2 h after addition of P i and one day later, from ca. 9.8 to ca. 12.5. The cell quota of Mn (q Mn ), and to a lesser extent Co, increased rapidly from 4.87 fg. cell −1 in the P‐ starved condition to 50.48 fg·cell −1 2 h afer addition of P i but decreased to 8.63 fg. Cell −1 by 6 h. Concentrations of Zn, As, Hf, Cu and sometimes Al, Mg, K, and Ca changed in a manner opposite to that of Mn and Co. The excretion of these cations, which was synchronized with the uptake of Mn and Co, may be important for a charge balancing in the cells. The ESR spectra showed that the high cellular Mn observed at 2 h after P addition was Mn 2+ which was taken up by the cells rather than adsorbed on the cell surface. These data combined with PP i data suggested that the behavior of q Mn is synchronized with the behavior of average chain length of PP i .