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González-Dávila M, Maldonado MT, González AG, Guo J, González-Santana D, Martel A, Santana-Casiano JM. Cu transport and complexation by the marine diatom Phaeodactylum tricornutum: Implications for trace metal complexation kinetics in the surface ocean. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 919:170752. [PMID: 38340864 DOI: 10.1016/j.scitotenv.2024.170752] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/26/2023] [Revised: 01/30/2024] [Accepted: 02/04/2024] [Indexed: 02/12/2024]
Abstract
Elucidating whether dissolved Cu uptake is kinetically or thermodynamically controlled, and the effects of speciation on Cu transport by phytoplankton will allow better modeling of the fate and impact of dissolved Cu in the ocean. To address these questions, we performed Cu physiological and physicochemical experiments using the model diatom, Phaeodactylum tricornutum, grown in natural North Atlantic seawater (0.44 nM Cu). Using competitive ligand equilibration-cathodic stripping voltammetry (CLE-CSV), we measured two organic ligand types released by P. tricornutum to bind Cu (L1 and L2) at concentrations of ~0.35 nM L1 and 1.3 nM L2. We also established the presence of two putative Cu-binding sites at the cell surface of P. tricornutum (S1 and S2) with log K differing by ~5 orders of magnitude (i.e., 12.9 vs. 8.1) and cell surface densities by 9-fold. Only the high-affinity binding sites, S1, exhibit reductase activity. Using voltammetric kinetic measurements and a theoretical kinetic model, we calculated the forward and dissociation rate constants of L1 and S1. Complementary 67Cu uptake experiments identified a high- and a low-affinity Cu uptake system in P. tricornutum, with half-saturation constant (Km) of 154 nM and 2.63 μM dissolved Cu, respectively. In the P. tricornutum genome, we identified a putative high-affinity Cu transporter (PtCTR49224) and a putative ZIP-like, low-affinity Cu transporter (PtZIP49400). PtCTR49224 has high homology to Homo sapiens hCTR1, which depending on the accessibility to extracellular reducing agents, the hCTR1 itself is involved in the reduction of Cu2+ to Cu+ before internalization. We combined these physiological and physicochemical data to calculate the rate constants for the internalization of Cu, and established that while the high-affinity Cu uptake system (S1) is borderline between a kinetically or thermodynamically controlled system, the low-affinity Cu transporters, S2, is thermodynamically-controlled. We revised the inverse relationship between the concentrations of inorganic complexes of essential metals (i.e., Ni, Fe, Co, Zn, Cd, Mn and Cu) in the mixed layer and the formation rate constant of metal transporters in phytoplankton, highlighting the link between the chemical properties of phytoplankton metal transporters and the availability and speciation of trace metals in the surface ocean.
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Affiliation(s)
- Melchor González-Dávila
- Instituto de Oceanografía y Cambio Global, IOCAG, Universidad de Las Palmas de Gran Canaria, ULPGC, Spain.
| | - Maria T Maldonado
- Department of Earth, Ocean, and Atmospheric Sciences, University of British Columbia Vancouver, BC, Canada.
| | - Aridane G González
- Instituto de Oceanografía y Cambio Global, IOCAG, Universidad de Las Palmas de Gran Canaria, ULPGC, Spain.
| | - Jian Guo
- Department of Earth, Ocean, and Atmospheric Sciences, University of British Columbia Vancouver, BC, Canada.
| | - David González-Santana
- Instituto de Oceanografía y Cambio Global, IOCAG, Universidad de Las Palmas de Gran Canaria, ULPGC, Spain.
| | - Antera Martel
- Banco Español de Algas, Instituto de Oceanografía y Cambio Global, IOCAG, Universidad de Las Palmas de Gran Canaria, ULPGC, Spain.
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Hu Y, Ji J, Cheng H, Luo R, Zhang J, Li W, Wang X, Zhang J, Yao Y. The miR408a-BBP-LAC3/CSD1 module regulates anthocyanin biosynthesis mediated by crosstalk between copper homeostasis and ROS homeostasis during light induction in Malus plants. J Adv Res 2023; 51:27-44. [PMID: 36371057 PMCID: PMC10491975 DOI: 10.1016/j.jare.2022.11.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2022] [Revised: 10/19/2022] [Accepted: 11/06/2022] [Indexed: 11/11/2022] Open
Abstract
INTRODUCTION The expression of miR408 is affected by copper (Cu) conditions and positively regulates anthocyanin biosynthesis in Arabidopsis. However, the underlying mechanisms by which miR408 regulates anthocyanin biosynthesis mediated by Cu homeostasis and reactive oxygen species (ROS) homeostasis remain unclear in Malus plants. OBJECTIVES Our study aims to elucidate how miR408a and its target, basic blue protein (BBP) regulate Cu homeostasis and ROS homeostasis, and anthocyanin biosynthesis in Malus plants. METHODS The roles of miR408a and its target BBP in regulating anthocyanin biosynthesis, Cu homeostasis, and ROS homeostasis were mainly identified in Malus plants. RESULTS We found that the BBP protein interacted with the copper-binding proteins LAC3 (laccase) and CSD1 (Cu/Zn SOD superoxide dismutase), indicating a potential crosstalk between Cu homeostasis and ROS homeostasis might be mediated by miR408 to regulate the anthocyanin accumulation. Further studies showed that overexpressing miR408a or suppressing BBP transiently significantly increased the expression of genes related to Cu binding and Cu transport, leading to anthocyanin accumulation under light induction in apple fruit and Malus plantlets. Consistently, opposite results were obtained when repressing miR408a or overexpressing BBP. Moreover, light induction significantly increased the expression of miR408a, CSD1, and LAC3, but significantly reduced the BBP expression, resulting in increased Cu content and anthocyanin accumulation. Furthermore, excessive Cu significantly increased the anthocyanin accumulation, accompanied by reduced expression of miR408a and Cu transport genes, and upregulated expression of Cu binding proteins including BBP, LAC3, and CSD1 to maintain the Cu homeostasis and ROS homeostasis in Malus plantlets. CONCLUSION Our findings provide new insights into the mechanism by which the miR408a-BBP-LAC3/CSD1 module perceives light and Cu signals regulating Cu and ROS homeostasis, ultimately affecting anthocyanin biosynthesis in Malus plants.
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Affiliation(s)
- Yujing Hu
- Beijing Advanced Innovation Center for Tree Breeding by Molecular Design, Beijing University of Agriculture, Beijing 102206, China; College of Plant Science and Technology, Beijing University of Agriculture, Beijing 102206, China; Beijing Key Laboratory for Agricultural Application and New Technique, Beijing 102206, China
| | - Jiayi Ji
- Beijing Advanced Innovation Center for Tree Breeding by Molecular Design, Beijing University of Agriculture, Beijing 102206, China; College of Plant Science and Technology, Beijing University of Agriculture, Beijing 102206, China; Beijing Key Laboratory for Agricultural Application and New Technique, Beijing 102206, China; Beijing Forestry University, China
| | - Hao Cheng
- Beijing Advanced Innovation Center for Tree Breeding by Molecular Design, Beijing University of Agriculture, Beijing 102206, China; College of Plant Science and Technology, Beijing University of Agriculture, Beijing 102206, China; Beijing Key Laboratory for Agricultural Application and New Technique, Beijing 102206, China
| | - Rongli Luo
- Beijing Advanced Innovation Center for Tree Breeding by Molecular Design, Beijing University of Agriculture, Beijing 102206, China; College of Plant Science and Technology, Beijing University of Agriculture, Beijing 102206, China; Beijing Key Laboratory for Agricultural Application and New Technique, Beijing 102206, China
| | - Jie Zhang
- Beijing Advanced Innovation Center for Tree Breeding by Molecular Design, Beijing University of Agriculture, Beijing 102206, China; College of Plant Science and Technology, Beijing University of Agriculture, Beijing 102206, China; Beijing Key Laboratory for Agricultural Application and New Technique, Beijing 102206, China
| | - Wenjing Li
- Beijing Advanced Innovation Center for Tree Breeding by Molecular Design, Beijing University of Agriculture, Beijing 102206, China; College of Plant Science and Technology, Beijing University of Agriculture, Beijing 102206, China; Beijing Key Laboratory for Agricultural Application and New Technique, Beijing 102206, China
| | - Xingsui Wang
- Beijing Advanced Innovation Center for Tree Breeding by Molecular Design, Beijing University of Agriculture, Beijing 102206, China; College of Plant Science and Technology, Beijing University of Agriculture, Beijing 102206, China; Beijing Key Laboratory for Agricultural Application and New Technique, Beijing 102206, China
| | - Jie Zhang
- Beijing Advanced Innovation Center for Tree Breeding by Molecular Design, Beijing University of Agriculture, Beijing 102206, China; College of Plant Science and Technology, Beijing University of Agriculture, Beijing 102206, China; Beijing Key Laboratory for Agricultural Application and New Technique, Beijing 102206, China.
| | - Yuncong Yao
- Beijing Advanced Innovation Center for Tree Breeding by Molecular Design, Beijing University of Agriculture, Beijing 102206, China; College of Plant Science and Technology, Beijing University of Agriculture, Beijing 102206, China; Beijing Key Laboratory for Agricultural Application and New Technique, Beijing 102206, China.
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Huapaya K, Echeveste P. Physiological responses of Humboldt current system diatoms to Fe and Cu co-limitation. MARINE ENVIRONMENTAL RESEARCH 2023; 187:105937. [PMID: 36958199 DOI: 10.1016/j.marenvres.2023.105937] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/18/2022] [Revised: 02/26/2023] [Accepted: 02/28/2023] [Indexed: 06/18/2023]
Abstract
Diatoms account for ∼20% of global primary production, often limited by the availability of Fe and other trace nutrients such as Cu. The present study examined the role of both metals in the physiology of two diatoms isolated from the Humboldt Currents System, the centric Chaetoceros c.f. dicipiens and the pennate Nitzschia c.f. draveillensis. Under Fe limitation, a decrease in specific growth rates and sizes of both species was observed, especially in Chaetoceros. However, regarding different photosynthetic parameters, Nitzschia was more impacted. The increase in Cu concentrations improved the physiology of both diatoms, mostly of Chaetoceros. When grown in mixed cultures and under co-limiting conditions, both species remained competive due to morphological advantages (i.e., lower cell size). These results may suggest that the increase of Cu under Fe limitation benefited C. c.f. dicipiens over N. c.f. draveillensis.
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Affiliation(s)
- Katiuska Huapaya
- Instituto de Ciencias Naturales Alexander von Humboldt, Facultad de Ciencias Del Mar y Recursos Biológicos, Universidad de Antofagasta, Antofagasta, Chile.
| | - Pedro Echeveste
- Instituto de Ciencias Naturales Alexander von Humboldt, Facultad de Ciencias Del Mar y Recursos Biológicos, Universidad de Antofagasta, Antofagasta, Chile; Instituto Milenio de Oceanografía, Chile
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Long M, Lelong A, Bucciarelli E, Le Grand F, Hégaret H, Soudant P. Physiological adaptation of the diatom Pseudo-nitzschia delicatissima under copper starvation. MARINE ENVIRONMENTAL RESEARCH 2023; 188:105995. [PMID: 37087845 DOI: 10.1016/j.marenvres.2023.105995] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/04/2023] [Revised: 04/10/2023] [Accepted: 04/11/2023] [Indexed: 05/03/2023]
Abstract
In the open ocean and particularly in iron (Fe)-limited environment, copper (Cu) deficiency might limit the growth of phytoplankton species. Cu is an essential trace metal used in electron-transfer reactions, such as respiration and photosynthesis, when bound to specific enzymes. Some phytoplankton species, such as the diatom Pseudo-nitzschia spp. can cope with Cu starvation through adaptative strategies. In this study, we investigated the physiological strategies of the marine diatom P. delicatissima against Cu starvation. Compared to the control, Cu starvation inhibited growth by 35%, but did not induce any excess mortality. Despite the bottleneck measured in the electron flow of the photosynthetic chain, cells of P. delicatissima conserved their photosynthesis ability. This photosynthesis maintenance was accompanied by structural changes of membranes, where pigments and lipid composition were strongly modified. Diatoms also strongly modified their metabolism, by redirecting their C allocation to energy storage under the form of triglycerides. By maintaining essential metabolic functions and storing energy under the form of lipids, these physiological adaptations might be a strategy enabling this diatom to later bloom under the return of favorable nutritional condition.
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Affiliation(s)
- Marc Long
- Univ Brest, CNRS, IRD, Ifremer, LEMAR, F-29280, Plouzane, France.
| | - Aurélie Lelong
- Univ Brest, CNRS, IRD, Ifremer, LEMAR, F-29280, Plouzane, France
| | - Eva Bucciarelli
- Univ Brest, CNRS, IRD, Ifremer, LEMAR, F-29280, Plouzane, France
| | | | - Hélène Hégaret
- Univ Brest, CNRS, IRD, Ifremer, LEMAR, F-29280, Plouzane, France
| | - Philippe Soudant
- Univ Brest, CNRS, IRD, Ifremer, LEMAR, F-29280, Plouzane, France
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Liu S, Storti M, Finazzi G, Bowler C, Dorrell RG. A metabolic, phylogenomic and environmental atlas of diatom plastid transporters from the model species Phaeodactylum. FRONTIERS IN PLANT SCIENCE 2022; 13:950467. [PMID: 36212359 PMCID: PMC9546453 DOI: 10.3389/fpls.2022.950467] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/22/2022] [Accepted: 09/02/2022] [Indexed: 06/16/2023]
Abstract
Diatoms are an important group of algae, contributing nearly 40% of total marine photosynthetic activity. However, the specific molecular agents and transporters underpinning the metabolic efficiency of the diatom plastid remain to be revealed. We performed in silico analyses of 70 predicted plastid transporters identified by genome-wide searches of Phaeodactylum tricornutum. We considered similarity with Arabidopsis thaliana plastid transporters, transcriptional co-regulation with genes encoding core plastid metabolic pathways and with genes encoded in the mitochondrial genomes, inferred evolutionary histories using single-gene phylogeny, and environmental expression trends using Tara Oceans meta-transcriptomics and meta-genomes data. Our data reveal diatoms conserve some of the ion, nucleotide and sugar plastid transporters associated with plants, such as non-specific triose phosphate transporters implicated in the transport of phosphorylated sugars, NTP/NDP and cation exchange transporters. However, our data also highlight the presence of diatom-specific transporter functions, such as carbon and amino acid transporters implicated in intricate plastid-mitochondria crosstalk events. These confirm previous observations that substrate non-specific triose phosphate transporters (TPT) may exist as principal transporters of phosphorylated sugars into and out of the diatom plastid, alongside suggesting probable agents of NTP exchange. Carbon and amino acid transport may be related to intricate metabolic plastid-mitochondria crosstalk. We additionally provide evidence from environmental meta-transcriptomic/meta- genomic data that plastid transporters may underpin diatom sensitivity to ocean warming, and identify a diatom plastid transporter (J43171) whose expression may be positively correlated with temperature.
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Affiliation(s)
- Shun Liu
- Institut de Biologie de l’Ecole Normale Supérieure (IBENS), Ecole Normale Supérieure, Centre National De La Recherche Scientifique (CNRS), Institut National De La Santé Et De La Recherche Médicale (INSERM), Université Paris Sciences et Lettres (PSL), Paris, France
- CNRS Research Federation for the study of Global Ocean Systems Ecology and Evolution, FR2022/Tara Oceans GOSEE, 3 rue Michel-Ange, Paris, France
| | - Mattia Storti
- Univ. Grenoble Alpes (UGA), Centre National Recherche Scientifique (CNRS), Commissariat Energie Atomique Energies Alternatives (CEA), Institut National Recherche Agriculture Alimentation Environnement (INRAE), Interdisciplinary Research Institute of Grenoble (IRIG), Laboratoire de Physiologie Cellulaire et Végétale (LPCV), Grenoble, France
| | - Giovanni Finazzi
- Univ. Grenoble Alpes (UGA), Centre National Recherche Scientifique (CNRS), Commissariat Energie Atomique Energies Alternatives (CEA), Institut National Recherche Agriculture Alimentation Environnement (INRAE), Interdisciplinary Research Institute of Grenoble (IRIG), Laboratoire de Physiologie Cellulaire et Végétale (LPCV), Grenoble, France
| | - Chris Bowler
- Institut de Biologie de l’Ecole Normale Supérieure (IBENS), Ecole Normale Supérieure, Centre National De La Recherche Scientifique (CNRS), Institut National De La Santé Et De La Recherche Médicale (INSERM), Université Paris Sciences et Lettres (PSL), Paris, France
- CNRS Research Federation for the study of Global Ocean Systems Ecology and Evolution, FR2022/Tara Oceans GOSEE, 3 rue Michel-Ange, Paris, France
| | - Richard G. Dorrell
- Institut de Biologie de l’Ecole Normale Supérieure (IBENS), Ecole Normale Supérieure, Centre National De La Recherche Scientifique (CNRS), Institut National De La Santé Et De La Recherche Médicale (INSERM), Université Paris Sciences et Lettres (PSL), Paris, France
- CNRS Research Federation for the study of Global Ocean Systems Ecology and Evolution, FR2022/Tara Oceans GOSEE, 3 rue Michel-Ange, Paris, France
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Copper Requirement and Acquisition by Marine Microalgae. Microorganisms 2022; 10:microorganisms10091853. [PMID: 36144455 PMCID: PMC9502191 DOI: 10.3390/microorganisms10091853] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2022] [Revised: 09/06/2022] [Accepted: 09/12/2022] [Indexed: 11/24/2022] Open
Abstract
Copper is a critical metal nutrient required by marine microalgae but may be toxic when supplied in excess. Maintaining an optimal intracellular Cu content is thus fundamentally necessary for microalgae and relies on cellular regulatory metabolisms and the process of Cu uptake that buffers the variation in environmental Cu availability. In this article the current progress in understanding the Cu requirements and acquisition mechanisms of marine microalgae is reviewed. Cu requirement by microalgae is primarily determined by the amount of Cu-dependent enzymes involved in cellular metabolisms and can be adjusted by Cu-sparing pathways. Decrease in metabolic Cu quotas caused a decline in the abundance of cuproenzymes and the dependent cellular metabolisms, and an induction of Cu acquisition pathways. Conventional models of Cu uptake describe the dependence of Cu uptake rate on free Cu2+ ions or kinetically labile species. A reductive, high-affinity Cu uptake system in marine microalgae is identified which enables cells to directly utilize organically complexed Cu, highlighting the importance of cell surface Cu reduction in the marine Cu cycle. This review provides new insights into Cu uptake models that may update the existing knowledge of Cu availability in the ocean.
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Pinseel E, Nakov T, Van den Berge K, Downey KM, Judy KJ, Kourtchenko O, Kremp A, Ruck EC, Sjöqvist C, Töpel M, Godhe A, Alverson AJ. Strain-specific transcriptional responses overshadow salinity effects in a marine diatom sampled along the Baltic Sea salinity cline. THE ISME JOURNAL 2022; 16:1776-1787. [PMID: 35383290 PMCID: PMC9213524 DOI: 10.1038/s41396-022-01230-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/04/2021] [Revised: 03/16/2022] [Accepted: 03/21/2022] [Indexed: 05/01/2023]
Abstract
The salinity gradient separating marine and freshwater environments represents a major ecological divide for microbiota, yet the mechanisms by which marine microbes have adapted to and ultimately diversified in freshwater environments are poorly understood. Here, we take advantage of a natural evolutionary experiment: the colonization of the brackish Baltic Sea by the ancestrally marine diatom Skeletonema marinoi. To understand how diatoms respond to low salinity, we characterized transcriptomic responses of acclimated S. marinoi grown in a common garden. Our experiment included eight strains from source populations spanning the Baltic Sea salinity cline. Gene expression analysis revealed that low salinities induced changes in the cellular metabolism of S. marinoi, including upregulation of photosynthesis and storage compound biosynthesis, increased nutrient demand, and a complex response to oxidative stress. However, the strain effect overshadowed the salinity effect, as strains differed significantly in their response, both regarding the strength and the strategy (direction of gene expression) of their response. The high degree of intraspecific variation in gene expression observed here highlights an important but often overlooked source of biological variation associated with how diatoms respond to environmental change.
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Affiliation(s)
- Eveline Pinseel
- Department of Biological Sciences, University of Arkansas, Fayetteville, AR, USA.
| | - Teofil Nakov
- Department of Biological Sciences, University of Arkansas, Fayetteville, AR, USA
| | - Koen Van den Berge
- Department of Statistics, University of California, Berkeley, CA, USA
- Department of Applied Mathematics, Computer Science and Statistics, Ghent University, Ghent, Belgium
- Bioinformatics Institute Ghent, Ghent University, Ghent, Belgium
| | - Kala M Downey
- Department of Biological Sciences, University of Arkansas, Fayetteville, AR, USA
| | - Kathryn J Judy
- Department of Biological Sciences, University of Arkansas, Fayetteville, AR, USA
| | - Olga Kourtchenko
- Department of Marine Sciences, University of Gothenburg, Gothenburg, Sweden
| | - Anke Kremp
- Leibniz-Institute for Baltic Sea Research Warnemünde, Rostock, Germany
| | - Elizabeth C Ruck
- Department of Biological Sciences, University of Arkansas, Fayetteville, AR, USA
| | - Conny Sjöqvist
- Environmental and Marine Biology, Åbo Akademi University, Åbo, Finland
| | - Mats Töpel
- Department of Marine Sciences, University of Gothenburg, Gothenburg, Sweden
| | - Anna Godhe
- Department of Marine Sciences, University of Gothenburg, Gothenburg, Sweden
| | - Andrew J Alverson
- Department of Biological Sciences, University of Arkansas, Fayetteville, AR, USA.
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Kong L, Price NM. Light Stimulates Copper-Limited Growth of an Oceanic Diatom by Increasing Cellular Copper(II) Reduction─A Rate-Determining Step in Copper Uptake. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2022; 56:9103-9111. [PMID: 35549243 DOI: 10.1021/acs.est.2c01479] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Uptake of Cu by Thalassiosira oceanica requires that Cu(II) is reduced to Cu(I) prior to transport across the cell membrane. The reduction step is mediated biochemically by cellular reductases active with a broad range of Cu chemical species. Here, we report on the cellular Cu(II) reduction and Cu(I) uptake of a diatom under saturating and subsaturating irradiance. An increase in growth irradiance, from 50 to 400 μmol photons m-2 s-1, increased the rate of extracellular Cu(II) reduction and steady-state Cu uptake. Under these conditions, Cu-limited cells acquired Cu more efficiently and maintained faster rates of growth than Cu-limited cells in low light. Pseudo-first-order reaction rate constants were about 70-fold faster for Cu(I) uptake than for Cu(II) reduction so that reduction was the rate-determining step in Cu acquisition. Accordingly, steady-state Cu uptake rates predicted from the reduction rate constants agreed well with measured rates of Cu uptake obtained from cultures growing at low nanomolar Cu concentrations. Transcript abundance of putative Cu(II) reductases followed a similar pattern to cupric reductase activity, increasing in Cu-limited cells and with increasing growth irradiance. The results are significant in showing Cu(II) reduction as the rate-determining step in Cu uptake: they suggest that biologically mediated Cu(II) reduction may be an important part of the Cu cycle in surface waters of the open sea.
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Affiliation(s)
- Liangliang Kong
- Department of Biology, McGill University, Montréal, Québec H3A 1B1, Canada
- College of Marine Life Science, Ocean University of China, Qingdao 266001, Shandong, China
| | - Neil M Price
- Department of Biology, McGill University, Montréal, Québec H3A 1B1, Canada
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