View in EDS

Utilization of inorganic carbon by the coccolithophorid Emiliania huxleyi (Lohmann) Kamptner.

Saved in:
Bibliographic Details
Title: Utilization of inorganic carbon by the coccolithophorid Emiliania huxleyi (Lohmann) Kamptner.
Authors: Nimer, N. A.1, Dixon, C. K.2, Merrett, M. J.1
Source: New Phytologist. Jan1992, Vol. 120 Issue 1, p153-158. 6p.
Subjects: Photosynthesis, Oxygen, Biological transport, Hydrophobic surfaces, Carbon, Dynamics
Abstract: Inorganic carbon-dependent photosynthetic oxygen evolution was saturated at a photon flux density of 100 μmol m-1s-1 for air-grown cells of a low calcifying strain of Emiliania huxleyi (Lohmann) Kamptner. Measurement of photosynthetic oxygen evolution at constant inorganic carbon concentration but varying pH showed that exogenous bicarbonate was not a major carbon source for photosynthesis. At pH 8.0 the concentration of dissolved inorganic carbon (DIC) required for the half-maximal rate of photosynthetic O2 evolution (K0.6 [DIC]) was 2.86 mM; the rate of non-enzymic dehydration of HCO3 greatly exceeding the rate of CO2. fixation. Carbon dioxide uptake occurs by diffusive entry as shown by the K0.5 [DIC]) of 12.5 μM at pH 5.0. Bicarbonate uptake, measured by the silicone-oil-layer centrigual filtering technique, did not show Michaelis-Menten type kinetics. The electrical membrane potential difference was determined from the distribution of the lipophilic cation retra[³H]phenylphosphonium (TPP) between cells and the media. Cells grown at pH 8.0 exhibited a negative membrane potential (inside of cell relative to outside) of about -60 mV. [ABSTRACT FROM AUTHOR]
Copyright of New Phytologist is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
Database: Engineering Source
Description
Abstract:<em>Inorganic</em> carbon-dependent photosynthetic oxygen evolution was saturated at a photon flux density of 100 μmol m-1s-1 for air-grown cells of a low calcifying strain of <em>Emiliania huxleyi</em> (Lohmann) Kamptner. Measurement of photosynthetic oxygen evolution at constant inorganic carbon concentration but varying pH showed that exogenous bicarbonate was not a major carbon source for photosynthesis. At pH 8.0 the concentration of dissolved inorganic carbon (DIC) required for the half-maximal rate of photosynthetic O2 evolution (<em>K</em>0.6 [DIC]) was 2.86 mM; the rate of non-enzymic dehydration of HCO3 greatly exceeding the rate of CO2. fixation. Carbon dioxide uptake occurs by diffusive entry as shown by the <em>K</em>0.5 [DIC]) of 12.5 μM at pH 5.0. Bicarbonate uptake, measured by the silicone-oil-layer centrigual filtering technique, did not show Michaelis-Menten type kinetics. The electrical membrane potential difference was determined from the distribution of the lipophilic cation retra[³H]phenylphosphonium (TPP) between cells and the media. Cells grown at pH 8.0 exhibited a negative membrane potential (inside of cell relative to outside) of about -60 mV. [ABSTRACT FROM AUTHOR]
ISSN:0028646X
DOI:10.1111/j.1469-8137.1992.tb01068.x