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Title: Simultaneous quantum yield measurements of carbon uptake and oxygen evolution in microalgal cultures

Abstract

The photosynthetic quantum yield (Φ), defined as carbon fixed or oxygen evolved per unit of light absorbed, is a fundamental but rarely determined biophysical parameter. A method to estimate Φ for both net carbon uptake and net oxygen evolution simultaneously can provide important insights into energy and mass fluxes. Here we present details for a novel system that allows quantification of carbon fluxes using pH oscillation and simultaneous oxygen fluxes by integration with a membrane inlet mass spectrometer. The pHOS system was validated using Phaeodactylum tricornutum cultured with continuous illumination of 110 μmole quanta m -2 s -1 at 25°C. Furthermore, simultaneous measurements of carbon and oxygen flux using the pHOS-MIMS and photon flux based on spectral absorption were carried out to explore the kinetics of Φ in P. tricornutum during its acclimation from low to high light (110 to 750 μmole quanta m -2 s -1). Comparing results at 0 and 24 hours, we observed strong decreases in cellular chlorophyll a (0.58 to 0.21 pg cell -1), Fv/Fm (0.71 to 0.59) and maximum Φ CO2 (0.019 to 0.004) and Φ O2 (0.028 to 0.007), confirming the transition toward high light acclimation. The Φ time-series indicated a non-synchronized acclimation responsemore » between carbon uptake and oxygen evolution, which has been previously inferred based on transcriptomic changes for a similar experimental design with the same diatom that lacked physiological data. The integrated pHOS-MIMS system can provide simultaneous carbon and oxygen measurements accurately, and at the time-resolution required to resolve high-resolution carbon and oxygen physiological dynamics.« less

Authors:
ORCiD logo [1];  [1];  [2];  [3];  [4];  [4];  [4];  [1];  [4]
  1. Univ. of California, San Diego, CA (United States). Scripps Inst. of Oceanography; J. Craig Venter Inst., La Jolla, CA (United States)
  2. Univ. of California, San Diego, CA (United States). Scripps Inst. of Oceanography; Smithsonian Tropical Research Inst., Apartado (Panama)
  3. J. Craig Venter Inst., La Jolla, CA (United States)
  4. Univ. of California, San Diego, CA (United States). Scripps Inst. of Oceanography
Publication Date:
Research Org.:
Univ. of California, San Diego, CA (United States); J. Craig Venter Inst., La Jolla, CA (United States)
Sponsoring Org.:
USDOE; Gordon and Betty Moore Foundation (GBMF)
OSTI Identifier:
1454903
Alternate Identifier(s):
OSTI ID: 1499884
Grant/Contract Number:  
EE0003373; SC0008593
Resource Type:
Published Article
Journal Name:
PLoS ONE
Additional Journal Information:
Journal Volume: 13; Journal Issue: 6; Journal ID: ISSN 1932-6203
Publisher:
Public Library of Science
Country of Publication:
United States
Language:
English
Subject:
59 BASIC BIOLOGICAL SCIENCES

Citation Formats

Du, Niu, Gholami, Pardis, Kline, David I., DuPont, Christopher L., Dickson, Andrew G., Mendola, Dominick, Martz, Todd, Allen, Andrew E., and Mitchell, B. Greg. Simultaneous quantum yield measurements of carbon uptake and oxygen evolution in microalgal cultures. United States: N. p., 2018. Web. doi:10.1371/journal.pone.0199125.
Du, Niu, Gholami, Pardis, Kline, David I., DuPont, Christopher L., Dickson, Andrew G., Mendola, Dominick, Martz, Todd, Allen, Andrew E., & Mitchell, B. Greg. Simultaneous quantum yield measurements of carbon uptake and oxygen evolution in microalgal cultures. United States. doi:10.1371/journal.pone.0199125.
Du, Niu, Gholami, Pardis, Kline, David I., DuPont, Christopher L., Dickson, Andrew G., Mendola, Dominick, Martz, Todd, Allen, Andrew E., and Mitchell, B. Greg. Tue . "Simultaneous quantum yield measurements of carbon uptake and oxygen evolution in microalgal cultures". United States. doi:10.1371/journal.pone.0199125.
@article{osti_1454903,
title = {Simultaneous quantum yield measurements of carbon uptake and oxygen evolution in microalgal cultures},
author = {Du, Niu and Gholami, Pardis and Kline, David I. and DuPont, Christopher L. and Dickson, Andrew G. and Mendola, Dominick and Martz, Todd and Allen, Andrew E. and Mitchell, B. Greg},
abstractNote = {The photosynthetic quantum yield (Φ), defined as carbon fixed or oxygen evolved per unit of light absorbed, is a fundamental but rarely determined biophysical parameter. A method to estimate Φ for both net carbon uptake and net oxygen evolution simultaneously can provide important insights into energy and mass fluxes. Here we present details for a novel system that allows quantification of carbon fluxes using pH oscillation and simultaneous oxygen fluxes by integration with a membrane inlet mass spectrometer. The pHOS system was validated using Phaeodactylum tricornutum cultured with continuous illumination of 110 μmole quanta m-2 s-1 at 25°C. Furthermore, simultaneous measurements of carbon and oxygen flux using the pHOS-MIMS and photon flux based on spectral absorption were carried out to explore the kinetics of Φ in P. tricornutum during its acclimation from low to high light (110 to 750 μmole quanta m-2 s-1). Comparing results at 0 and 24 hours, we observed strong decreases in cellular chlorophyll a (0.58 to 0.21 pg cell-1), Fv/Fm (0.71 to 0.59) and maximum ΦCO2 (0.019 to 0.004) and ΦO2 (0.028 to 0.007), confirming the transition toward high light acclimation. The Φ time-series indicated a non-synchronized acclimation response between carbon uptake and oxygen evolution, which has been previously inferred based on transcriptomic changes for a similar experimental design with the same diatom that lacked physiological data. The integrated pHOS-MIMS system can provide simultaneous carbon and oxygen measurements accurately, and at the time-resolution required to resolve high-resolution carbon and oxygen physiological dynamics.},
doi = {10.1371/journal.pone.0199125},
journal = {PLoS ONE},
number = 6,
volume = 13,
place = {United States},
year = {2018},
month = {6}
}

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record
DOI: 10.1371/journal.pone.0199125

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