FN Archimer Export Format
PT J
TI Cell surface acid-base properties of the cyanobacterium Synechococcus: Influences of nitrogen source, growth phase and N:P ratios
BT 
   ALESSI, D. S.
   OWTTRIM, G. W.
   KENNEY, J. P. L.
   LALONDE, Stefan
   KONHAUSER, K. O.
AS 1:1,2;2:2;3:3;4:4;5:1;6:5;7:2;
FF 1:;2:;3:;4:;5:;6:;7:;
C1 Nankai Univ, Coll Environm Sci & Engn, Tianjin 300071, Peoples R China.
   Univ Alberta, Dept Earth & Atmospher Sci, Edmonton, AB T6G 2E3, Canada.
   Univ Alberta, Dept Biol Sci, Edmonton, AB T6G 2E9, Canada.
   Imperial Coll, Dept Earth Sci & Engn, London SW7 2AZ, England.
   CNRS, European Inst Marine Studies, Lab Domaines Ocean, UMR6538,UMR 6538, Brest, France.
C2 UNIV NANKAI, CHINA
   UNIV ALBERTA, CANADA
   UNIV ALBERTA, CANADA
   IMPERIAL COLL, UK
   CNRS, FRANCE
UM LGO
IF 4.609
TC 15
UR https://archimer.ifremer.fr/doc/00639/75069/88234.pdf
LA English
DT Article
DE ;Synechococcus;Marine cyanobacteria;FTIR;Potentiometric titrations;Cell surface reactivity;Nitrogen and phosphate limitation
AB The distribution of many trace metals in the oceans is controlled by biological uptake. Recently, Liu et al. (2015) demonstrated the propensity for a marine cyanobacterium to adsorb cadmium from seawater, suggesting that cell surface reactivity might also play an important role in the cycling of metals in the oceans. However, it remains unclear how variations in cyanobacterial growth rates and nutrient supply might affect the chemical properties of their cellular surfaces. In this study we used potentiometric titrations and Fourier Transform Infrared (FT-IR) spectrometry to profile the key metabolic changes and surface chemical responses of a Synechococcus strain, PCC 7002, during different growth regimes. This included testing various nitrogen (N) to phosphorous (P) ratios (both nitrogen and phosphorous dependent), nitrogen sources (nitrate, ammonium and urea) and growth stages (exponential, stationary, and death phase). FT-IR spectroscopy showed that varying the growth substrates on which Synechococcus cells were cultured resulted in differences in either the type or abundance of cellular exudates produced or a change in the cell wall components. Potentiometric titration data were modeled using three distinct proton binding sites, with resulting pKa values for cells of the various growth conditions in the ranges of 4.96-5.51 (pKa(1)), 6.67-7.42 (pKa(2)) and 8.13-9.95 (pKa(3)). According to previous spectroscopic studies, these pKa ranges are consistent with carboxyl, phosphoryl, and amine groups, respectively. Comparisons between the titration data (for the cell surface) and FT-IR spectra (for the average cellular changes) generally indicate (1) that the nitrogen source is a greater determinant of ligand concentration than growth phase, and (2) that phosphorus limitation has a greater impact on Synechococcus cellular and extracellular properties than does nitrogen limitation. Taken together, these techniques indicate that nutritional quality during cell growth can noticeably influence the expression of cell surface ligands and their measurable densities. Given that cell surface charge ultimately affects metal adsorption, our results suggest that the cycling of metals by Synechococcus cells in the oceans may vary regionally. 
PY 2016
PD AUG
SO Geochimica Et Cosmochimica Acta
SN 0016-7037
PU Pergamon-elsevier Science Ltd
VL 187
UT 000379737800009
BP 179
EP 194
DI 10.1016/j.gca.2016.05.023
ID 75069
ER

EF