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Vítek P, Klem K. Raman imaging monitors the time-resolved response of A. thaliana to the artificial inhibition of PSII. Spectrochim Acta A Mol Biomol Spectrosc 2023; 291:122276. [PMID: 36623348 DOI: 10.1016/j.saa.2022.122276] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2022] [Revised: 12/20/2022] [Accepted: 12/22/2022] [Indexed: 06/17/2023]
Abstract
The short-term (0-96 h) response of A. thaliana to the oxidative stress induced by PSII inhibitor metribuzin was examined using Raman spectroscopy. Whole leaves of wildtype (WT, Col-0) and ros1 mutant were scanned and changes in carotenoids were examined. Strong differences in Raman intensity distributions between WT and ros1 were observed. A stronger decrease of carotenoid v1(C=C) band intensity across the leaf was observed in ros1 after 48 h of exposure to metribuzin. It can be assumed that higher sensitivity to oxidative stress in ros1 mutant results in significantly faster degradation of carotenoids.
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Affiliation(s)
- P Vítek
- Global Change Research Institute of the Czech Academy of Sciences, Bělidla 4a, 603 00 Brno, Czech Republic.
| | - K Klem
- Global Change Research Institute of the Czech Academy of Sciences, Bělidla 4a, 603 00 Brno, Czech Republic.
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2
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Hussain MI, Reigosa MJ. Secondary Metabolites, Ferulic Acid and p-Hydroxybenzoic Acid Induced Toxic Effects on Photosynthetic Process in Rumex acetosa L. Biomolecules 2021; 11:biom11020233. [PMID: 33562880 PMCID: PMC7915730 DOI: 10.3390/biom11020233] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2020] [Revised: 01/30/2021] [Accepted: 02/02/2021] [Indexed: 11/26/2022] Open
Abstract
The elimination of broadleaf weeds from agricultural fields has become an urgent task in plant and environment protection. Allelopathic control is considered a potential approach because of its exclusive and ecological safety measures. Plant secondary metabolites also called allelochemicals are released from plant leaves, roots, stem, bark, flowers and play significant roles in soil rhizosphere signaling, chemical ecology, and plant defense. The present study was carried out to evaluate the impact of two allelochemicals; ferulic acid (FA) and p-hydroxybenzoic acid (pHBA) on photosynthetic characteristics; Fv/Fm: efficiency of photosystem II photochemistry in the dark-adapted state; ΦPSII: photosynthetic quantum yield; NPQ, non-photochemical quenching; qP, photochemical quenching, and photon energy dissipation (1−qP)/NPQ in Rumex acetosa following 6 days exposure. R. acetosa seedlings were grown in perlite culture, irrigated with Hoagland solution and treated with allelopathic compounds FA and pHBA and were evaluated against the photosynthetic attributes. Both compounds behaved as potent inhibitors of photosynthetic traits such as Fv/Fm, ΦPSII, qP, and NPQ in R. acetosa. Photon energy dissipation (1−qP)/NPQ increased significantly from days 3 to 6. Higher dissipation of absorbed energy indicates the inactivation state of reaction centers and their inability to effectively use the absorbed energy in photosynthesis. These results indicated the potential allelopathic application of FA and pHBA for control of broadleaf weed, Rumex acetosa.
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Affiliation(s)
- M. Iftikhar Hussain
- Department of Plant Biology and Soil Science, Faculty of Biology, University of Vigo, Campus Lagoas-Marcosende, 36310 Vigo, Spain;
- CITACA, Agri-Food Research and Transfer Cluster, Campus da Auga, University of Vigo, 32004 Ourense, Spain
- Correspondence:
| | - Manuel J. Reigosa
- Department of Plant Biology and Soil Science, Faculty of Biology, University of Vigo, Campus Lagoas-Marcosende, 36310 Vigo, Spain;
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3
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Thomas MC, Flores F, Kaserzon S, Reeks TA, Negri AP. Toxicity of the herbicides diuron, propazine, tebuthiuron, and haloxyfop to the diatom Chaetoceros muelleri. Sci Rep 2020; 10:19592. [PMID: 33177549 PMCID: PMC7658992 DOI: 10.1038/s41598-020-76363-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Accepted: 10/23/2020] [Indexed: 01/16/2023] Open
Abstract
Conventional photosystem II (PSII) herbicides applied in agriculture can pose significant environmental risks to aquatic environments. In response to the frequent detection of these herbicides in the Great Barrier Reef (GBR) catchment area, transitions towards 'alternative' herbicides are now widely supported. However, water quality guideline values (WQGVs) for alternative herbicides are lacking and their potential ecological impacts on tropical marine species are generally unknown. To improve our understanding of the risks posed by some of these alternative herbicides on marine species under tropical conditions, we tested the effects of four herbicides on the widely distributed diatom Chaetoceros muelleri. The PSII herbicides diuron, propazine, and tebuthiuron induced substantial reductions in both 24 h effective quantum yields (ΔF/Fm') and 3-day specific growth rates (SGR). The effect concentrations, which reduced ΔF/Fm' by 50% (EC50), ranged from 4.25 µg L-1 diuron to 48.6 µg L-1 propazine, while the EC50s for SGR were on average threefold higher, ranging from 12.4 µg L-1 diuron to 187 µg L-1 tebuthiuron. Our results clearly demonstrated that inhibition of ΔF/Fm' in PSII is directly linked to reduced growth (R2 = 0.95) in this species, further supporting application of ΔF/Fm' inhibition as a valid bioindicator of ecological relevance for PSII herbicides that could contribute to deriving future WQGVs. In contrast, SGR and ΔF/Fm' of C. muelleri were nonresponsive to the non-PSII herbicide haloxyfop at the highest concentration tested (4570 µg L-1), suggesting haloxyfop does not pose a risk to C. muelleri. The toxicity thresholds (e.g. no effect concentrations; NECs) identified in this study will contribute to the derivation of high-reliability marine WQGVs for some alternative herbicides detected in GBR waters and support future assessments of the cumulative risks of complex herbicide mixtures commonly detected in coastal waters.
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Affiliation(s)
- Marie C Thomas
- Australian Institute of Marine Science, Townsville, QLD, 4810, Australia.
| | - Florita Flores
- Australian Institute of Marine Science, Townsville, QLD, 4810, Australia
| | - Sarit Kaserzon
- Queensland Alliance for Environmental Health Sciences (QAEHS), The University of Queensland, Woolloongabba, QLD, 4102, Australia
| | - Timothy A Reeks
- Queensland Alliance for Environmental Health Sciences (QAEHS), The University of Queensland, Woolloongabba, QLD, 4102, Australia
| | - Andrew P Negri
- Australian Institute of Marine Science, Townsville, QLD, 4810, Australia
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Forini MML, Antunes DR, Cavalcante LAF, Pontes MS, Biscalchim ÉR, Sanches AO, Santiago EF, Fraceto LF, Grillo R. Fabrication and Characterization of a Novel Herbicide Delivery System with Magnetic Collectability and Its Phytotoxic Effect on Photosystem II of Aquatic Macrophyte. J Agric Food Chem 2020; 68:11105-11113. [PMID: 32915575 DOI: 10.1021/acs.jafc.0c03645] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
The use of nano- and microparticles as a release system for agrochemicals has been increasing in agricultural sector. However, the production of eco-friendly and smart carriers that can be easily handled in the environment is still a challenge for this technology. In this context, we have developed a biodegradable release system for the herbicide atrazine with magnetic properties. Herein, we investigated the (a) physicochemical properties of the atrazine-loaded magnetic poly(ε-caprolactone) microparticles (MPs:ATZ), (b) in vitro release kinetic profile of the herbicide, and (c) phytotoxicity toward photosynthesis in the aquatic fern Azolla caroliniana. The encapsulation efficiency of the herbicide in the MPs:ATZ was ca. 69%, yielding spherical microparticles with a diameter of ca. 100 μm, a sustained-release profile, and easily manipulated with an external magnetic field. Also, phytotoxicity issues showed that the MPs:ATZ maintained their herbicidal activity via inhibition of PSII, showing lower toxicity compared with the nonencapsulated ATZ at 0.01 and 0.02 μmol·L-1. Therefore, this technology may conveniently promote a novel magnetic controlled release of the herbicide ATZ (with the potential to be collected from a watercourse) and act as a nutrient boost to the nontarget plant, with good herbicidal activity and reduced risk to the environment.
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Affiliation(s)
- Mariana M L Forini
- Department of Physics and Chemistry, School of Engineering, São Paulo State University (UNESP), Ilha Solteira, SP 15385-000, Brazil
| | - Débora R Antunes
- Department of Physics and Chemistry, School of Engineering, São Paulo State University (UNESP), Ilha Solteira, SP 15385-000, Brazil
| | - Luiz A F Cavalcante
- Department of Physics and Chemistry, School of Engineering, São Paulo State University (UNESP), Ilha Solteira, SP 15385-000, Brazil
| | - Montcharles S Pontes
- Natural Resources Program, Center for Natural Resources Studies (CERNA), Mato Grosso do Sul State University (UEMS), Dourados, Mato Grosso do Sul 79804-970, Brazil
| | - Érica R Biscalchim
- Department of Physics and Chemistry, School of Engineering, São Paulo State University (UNESP), Ilha Solteira, SP 15385-000, Brazil
| | - Alex O Sanches
- Department of Physics and Chemistry, School of Engineering, São Paulo State University (UNESP), Ilha Solteira, SP 15385-000, Brazil
| | - Etenaldo F Santiago
- Natural Resources Program, Center for Natural Resources Studies (CERNA), Mato Grosso do Sul State University (UEMS), Dourados, Mato Grosso do Sul 79804-970, Brazil
| | - Leonardo F Fraceto
- Department of Environmental Engineering, Institute of Science and Technology (ICTS), São Paulo State University (UNESP), Sorocaba, SP 18087-180, Brazil
| | - Renato Grillo
- Department of Physics and Chemistry, School of Engineering, São Paulo State University (UNESP), Ilha Solteira, SP 15385-000, Brazil
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McMurray LS, Preston C, Vandenberg A, Mao D, Bett KE, Paull JG. Induced novel psbA mutation (Ala 251 to Thr) in higher plants confers resistance to PSII inhibitor metribuzin in Lens culinaris. Pest Manag Sci 2019; 75:1564-1570. [PMID: 30632275 DOI: 10.1002/ps.5328] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/08/2018] [Revised: 01/08/2019] [Accepted: 01/08/2019] [Indexed: 06/09/2023]
Abstract
BACKGROUND Weed competition is a major limitation to worldwide lentil (Lens culinaris Medik.) production in part due to limited effective safe herbicide options. Metribuzin is a photosystem II inhibiting herbicide that provides broad spectrum weed control, however it causes excessive injury in lentil. Dose response analysis of photosystem II inhibiting herbicides and DNA sequencing of the psbA chloroplast gene occurred to quantify the spectrum and mechanism of herbicide resistance in two ethyl-methanesulfonate (EMS) induced mutant lentils. RESULTS Compared to susceptible parent PBA Flash, the level of metribuzin resistance was 33-fold for mutant M043 and 10-fold for M009. No improvement in resistance occurred in either mutant to bromoxynil, diuron, bromacil and atrazine herbicides. Nucleotide sequencing of the psbA gene of both mutants identified a substitution at position 751 compared to PBA Flash. The resulting deduced amino acid sequence indicated an Ala251 Thr substitution as being most likely responsible for the high level of metribuzin resistance. CONCLUSIONS The Ala251 Thr substitution discovered in this study is unique in mutagenized higher plants and the first report of an induced psbA target site mutation in higher plants. This target site metribuzin resistance is likely to have a significant impact on lentil production in Australia and worldwide. © 2019 Society of Chemical Industry.
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Affiliation(s)
- Larn S McMurray
- School of Agriculture, Food and Wine, The University of Adelaide, Adelaide, South Australia, Australia
- South Australian Research and Development Institute, Clare, South Australia, Australia
| | - Christopher Preston
- School of Agriculture, Food and Wine, The University of Adelaide, Adelaide, South Australia, Australia
| | - Albert Vandenberg
- Department of Plant Sciences/Crop Development Centre, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
| | - Dili Mao
- South Australian Research and Development Institute, Clare, South Australia, Australia
| | - Kirstin E Bett
- Department of Plant Sciences/Crop Development Centre, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
| | - Jeffrey G Paull
- School of Agriculture, Food and Wine, The University of Adelaide, Adelaide, South Australia, Australia
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Shitov AV, Terentyev VV, Zharmukhamedov SK, Rodionova MV, Karacan M, Karacan N, Klimov VV, Allakhverdiev SI. Is carbonic anhydrase activity of photosystem II required for its maximum electron transport rate? Biochim Biophys Acta Bioenerg 2018; 1859:292-299. [PMID: 29410217 DOI: 10.1016/j.bbabio.2018.01.009] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/08/2018] [Accepted: 01/26/2018] [Indexed: 01/05/2023]
Abstract
It is known, that the multi-subunit complex of photosystem II (PSII) and some of its single proteins exhibit carbonic anhydrase activity. Previously, we have shown that PSII depletion of HCO3-/CO2 as well as the suppression of carbonic anhydrase activity of PSII by a known inhibitor of α‑carbonic anhydrases, acetazolamide (AZM), was accompanied by a decrease of electron transport rate on the PSII donor side. It was concluded that carbonic anhydrase activity was required for maximum photosynthetic activity of PSII but it was not excluded that AZM may have two independent mechanisms of action on PSII: specific and nonspecific. To investigate directly the specific influence of carbonic anhydrase inhibition on the photosynthetic activity in PSII we used another known inhibitor of α‑carbonic anhydrase, trifluoromethanesulfonamide (TFMSA), which molecular structure and physicochemical properties are quite different from those of AZM. In this work, we show for the first time that TFMSA inhibits PSII carbonic anhydrase activity and decreases rates of both the photo-induced changes of chlorophyll fluorescence yield and the photosynthetic oxygen evolution. The inhibitory effect of TFMSA on PSII photosynthetic activity was revealed only in the medium depleted of HCO3-/CO2. Addition of exogenous HCO3- or PSII electron donors led to disappearance of the TFMSA inhibitory effect on the electron transport in PSII, indicating that TFMSA inhibition site was located on the PSII donor side. These results show the specificity of TFMSA action on carbonic anhydrase and photosynthetic activities of PSII. In this work, we discuss the necessity of carbonic anhydrase activity for the maximum effectiveness of electron transport on the donor side of PSII.
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Affiliation(s)
- Alexandr V Shitov
- Institute of Basic Biological Problems, Russian Academy of Sciences, Institutskaya Street 2, Pushchino, Moscow Region 142290, Russia.
| | - Vasily V Terentyev
- Institute of Basic Biological Problems, Russian Academy of Sciences, Institutskaya Street 2, Pushchino, Moscow Region 142290, Russia
| | - Sergey K Zharmukhamedov
- Institute of Basic Biological Problems, Russian Academy of Sciences, Institutskaya Street 2, Pushchino, Moscow Region 142290, Russia; Controlled Photobiosynthesis Laboratory, Institute of Plant Physiology, Russian Academy of Sciences, Botanicheskaya Street 35, Moscow 127276, Russia
| | - Margarita V Rodionova
- Controlled Photobiosynthesis Laboratory, Institute of Plant Physiology, Russian Academy of Sciences, Botanicheskaya Street 35, Moscow 127276, Russia
| | - Mehmet Karacan
- Gazi University, Science Faculty, Department of Chemistry, 06500 Ankara, Turkey
| | - Nurcan Karacan
- Gazi University, Science Faculty, Department of Chemistry, 06500 Ankara, Turkey
| | - Vyacheslav V Klimov
- Institute of Basic Biological Problems, Russian Academy of Sciences, Institutskaya Street 2, Pushchino, Moscow Region 142290, Russia
| | - Suleyman I Allakhverdiev
- Institute of Basic Biological Problems, Russian Academy of Sciences, Institutskaya Street 2, Pushchino, Moscow Region 142290, Russia; Controlled Photobiosynthesis Laboratory, Institute of Plant Physiology, Russian Academy of Sciences, Botanicheskaya Street 35, Moscow 127276, Russia; Department of Plant Physiology, Faculty of Biology, M.V. Lomonosov Moscow State University, Leninskie Gory 1-12, Moscow 119991, Russia; Moscow Institute of Physics and Technology, Institutsky lane 9, Dolgoprudny, Moscow Region 141700, Russia; Institute of Molecular Biology and Biotechnology, Azerbaijan National Academy of Sciences, Matbuat Avenue 2a, Baku 1073, Azerbaijan.
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7
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Magyar M, Sipka G, Kovács L, Ughy B, Zhu Q, Han G, Špunda V, Lambrev PH, Shen JR, Garab G. Rate-limiting steps in the dark-to-light transition of Photosystem II - revealed by chlorophyll-a fluorescence induction. Sci Rep 2018; 8:2755. [PMID: 29426901 DOI: 10.1038/s41598-41018-21195-41592] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2017] [Accepted: 01/31/2018] [Indexed: 05/28/2023] Open
Abstract
Photosystem II (PSII) catalyses the photoinduced oxygen evolution and, by producing reducing equivalents drives, in concert with PSI, the conversion of carbon dioxide to sugars. Our knowledge about the architecture of the reaction centre (RC) complex and the mechanisms of charge separation and stabilisation is well advanced. However, our understanding of the processes associated with the functioning of RC is incomplete: the photochemical activity of PSII is routinely monitored by chlorophyll-a fluorescence induction but the presently available data are not free of controversy. In this work, we examined the nature of gradual fluorescence rise of PSII elicited by trains of single-turnover saturating flashes (STSFs) in the presence of a PSII inhibitor, permitting only one stable charge separation. We show that a substantial part of the fluorescence rise originates from light-induced processes that occur after the stabilisation of charge separation, induced by the first STSF; the temperature-dependent relaxation characteristics suggest the involvement of conformational changes in the additional rise. In experiments using double flashes with variable waiting times (∆τ) between them, we found that no rise could be induced with zero or short ∆τ, the value of which depended on the temperature - revealing a previously unknown rate-limiting step in PSII.
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Affiliation(s)
- Melinda Magyar
- Institute of Plant Biology, Biological Research Centre, Hungarian Academy of Sciences, Temesvári körút 62, H-6726, Szeged, Hungary
| | - Gábor Sipka
- Institute of Plant Biology, Biological Research Centre, Hungarian Academy of Sciences, Temesvári körút 62, H-6726, Szeged, Hungary
| | - László Kovács
- Institute of Plant Biology, Biological Research Centre, Hungarian Academy of Sciences, Temesvári körút 62, H-6726, Szeged, Hungary
| | - Bettina Ughy
- Institute of Plant Biology, Biological Research Centre, Hungarian Academy of Sciences, Temesvári körút 62, H-6726, Szeged, Hungary
| | - Qingjun Zhu
- Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany the Chinese Academy of Sciences, Beijing, 100093, China
| | - Guangye Han
- Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany the Chinese Academy of Sciences, Beijing, 100093, China
| | - Vladimír Špunda
- Department of Physics, Faculty of Science, University of Ostrava, Chittussiho 10, CZ-710 00, Ostrava, Czech Republic
- Global Change Research Institute, Czech Academy of Sciences, Bělidla 986/4a, 603 00, Brno, Czech Republic
| | - Petar H Lambrev
- Institute of Plant Biology, Biological Research Centre, Hungarian Academy of Sciences, Temesvári körút 62, H-6726, Szeged, Hungary
| | - Jian-Ren Shen
- Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany the Chinese Academy of Sciences, Beijing, 100093, China
- Research Institute for Interdisciplinary Science and Graduate School of Natural Science and Technology, Okayama University, 1-1, Naka 3-chome, Tsushima, Okayama, 700-8530, Japan
| | - Győző Garab
- Institute of Plant Biology, Biological Research Centre, Hungarian Academy of Sciences, Temesvári körút 62, H-6726, Szeged, Hungary.
- Department of Physics, Faculty of Science, University of Ostrava, Chittussiho 10, CZ-710 00, Ostrava, Czech Republic.
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Pedroso RM, Al-Khatib K, Alarcón-Reverte R, Fischer AJ. A psbA mutation (Val219 to Ile) causes resistance to propanil and increased susceptibility to bentazon in Cyperus difformis. Pest Manag Sci 2016; 72:1673-1680. [PMID: 26929096 DOI: 10.1002/ps.4267] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/10/2015] [Revised: 02/18/2016] [Accepted: 02/22/2016] [Indexed: 06/05/2023]
Abstract
BACKGROUND Propanil-resistant (R) Cyperus difformis populations were recently confirmed in California rice fields. To date, propanil resistance in other weed species has been associated with enhanced aryl acylamidase (AAA)-mediated propanil conversion into 3,4-dichloroaniline. Our objectives were to determine the level of propanil resistance and cross-resistance to other PSII inhibitors in C. difformis lines, and to elucidate the mechanism of propanil resistance. RESULTS The propanil-R line had a 14-fold propanil resistance and increased resistance to bromoxynil, diuron and metribuzin, but not to atrazine. The R line, however, displayed a fourfold increased susceptibility to bentazon. Interestingly, susceptible (S) plants accumulated more 3,4-dichloroaniline and were more injured by propanil and carbaryl (AAA-inhibitor) applications than R plants, suggesting that propanil metabolism is not the resistance mechanism. psbA gene sequence analysis indicated a valine-219-isoleucine (Val219 Ile) amino acid exchange in the propanil-R chloroplast D1 protein. CONCLUSION The D1 Val219 Ile modification in C. difformis causes resistance to propanil, diuron, metribuzin and bromoxynil but increased susceptibility to bentazon, suggesting that the Val219 residue participates in binding of these herbicides. This is the first report of a higher plant exhibiting target-site propanil resistance. Tank mixing of bentazon and propanil, where permitted, can control both propanil-R and propanil-S C. difformis and prevent the spread of the resistant phenotype. © 2016 Society of Chemical Industry.
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Affiliation(s)
- Rafael M Pedroso
- Department of Plant Sciences, University of California, Davis, CA, USA
| | - Kassim Al-Khatib
- Department of Plant Sciences, University of California, Davis, CA, USA
| | | | - Albert J Fischer
- Department of Plant Sciences, University of California, Davis, CA, USA
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9
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Huang W, Yang YJ, Zhang JL, Hu H, Zhang SB. PSI photoinhibition is more related to electron transfer from PSII to PSI rather than PSI redox state in Psychotria rubra. Photosynth Res 2016; 129:85-92. [PMID: 27236700 DOI: 10.1007/s11120-016-0275-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/17/2015] [Accepted: 05/14/2016] [Indexed: 05/07/2023]
Abstract
Although it has been believed that wild-type plants are capable of protecting photosystem I (PSI) under high light, our previous study indicates that PSI is sensitive to high light in the shade-established tree species Psychotria rubra. However, the underlying physiological mechanisms are unclear. In this study, we examined the roles of electron transfer from PSII to PSI and PSI redox state in PSI photoinhibition in P. rubra by treatments with lincomycin (Lin), diuron (DCMU), and methyl viologen (MV). After exposure to 2000 μmol photons m(-2) s(-1) for 2 h, PSI activity decreased by 35, 29, 3, and 49 % in samples treated with H2O, Lin, DCMU, and MV, respectively. Meanwhile, the MV-treated samples showed higher P700 oxidation ratio than the H2O-treated samples, suggesting the PSI photoinhibition under high light was accompanied by high levels of P700 oxidation ratio. PSI photoinhibition was alleviated in the DCMU-treated samples but was accelerated in the MV-treated samples, suggesting that PSI photoinhibition in P. rubra was mainly controlled by electron transfer from PSII to PSI. Taking together, PSI photoinhibition is more related to electron transfer from PSII to PSI rather than PSI redox state in P. rubra, which is different from the mechanisms of PSI photoinhibition in Arabidopsis thaliana and cucumber.
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Affiliation(s)
- Wei Huang
- Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla, 666303, Yunnan, China
- Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, 650201, Yunnan, China
| | - Ying-Jie Yang
- Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, 650201, Yunnan, China
| | - Jiao-Lin Zhang
- Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla, 666303, Yunnan, China
| | - Hong Hu
- Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, 650201, Yunnan, China
| | - Shi-Bao Zhang
- Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, 650201, Yunnan, China.
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10
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Copin PJ, Chèvre N. Modelling the effects of pulse exposure of several PSII inhibitors on two algae. Chemosphere 2015; 137:70-77. [PMID: 26011414 DOI: 10.1016/j.chemosphere.2015.05.035] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/06/2015] [Revised: 05/11/2015] [Accepted: 05/12/2015] [Indexed: 06/04/2023]
Abstract
Subsequent to crop application and during precipitation events, herbicides can reach surface waters in pulses of high concentrations. These pulses can exceed the Annual Average Environmental Quality Standards (AA-EQS), defined in the EU Water Framework Directive, which aims to protect the aquatic environment. A model was developed in a previous study to evaluate the effects of pulse exposure for the herbicide isoproturon on the alga Scenedesmus vacuolatus. In this study, the model was extended to other substances acting as photosystem II inhibitors and to other algae. The measured and predicted effects were equivalent when pulse exposure of atrazine and diuron were tested on S. vacuolatus. The results were consistent for isoproturon on the alga Pseudokirchneriella subcapitata. The model is thus suitable for the effect prediction of phenylureas and triazines and for the algae used: S. vacuolatus and P. subcapitata. The toxicity classification obtained from the dose-response curves (diuron>atrazine>isoproturon) was conserved for the pulse exposure scenarios modelled for S. vacuolatus. Toxicity was identical for isoproturon on the two algae when the dose-response curves were compared and also for the pulse exposure scenarios. Modelling the effects of any pulse scenario of photosystem II inhibitors on algae is therefore feasible and only requires the determination of the dose-response curves of the substance and growth rate of unexposed algae. It is crucial to detect the longest pulses when measurements of herbicide concentrations are performed in streams because the model showed that they principally affect the cell density inhibition of algae.
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Affiliation(s)
- Pierre-Jean Copin
- Institut des dynamiques de la surface terrestre (IDYST), Faculté des Géosciences et de l'Environment, Université de Lausanne, Géopolis, Quartier Mouline, CH-1015 Lausanne, Switzerland.
| | - Nathalie Chèvre
- Institut des dynamiques de la surface terrestre (IDYST), Faculté des Géosciences et de l'Environment, Université de Lausanne, Géopolis, Quartier Mouline, CH-1015 Lausanne, Switzerland.
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Wilkinson AD, Collier CJ, Flores F, Mercurio P, O’Brien J, Ralph PJ, Negri AP. A miniature bioassay for testing the acute phytotoxicity of photosystem II herbicides on seagrass. PLoS One 2015; 10:e0117541. [PMID: 25674791 PMCID: PMC4326278 DOI: 10.1371/journal.pone.0117541] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2014] [Accepted: 12/12/2014] [Indexed: 11/19/2022] Open
Abstract
Photosystem II (PSII) herbicides have been detected in nearshore tropical waters such as those of the Great Barrier Reef and may add to the pressure posed by runoff containing sediments and nutrients to threatened seagrass habitats. There is a growing number of studies into the potential effects of herbicides on seagrass, generally using large experimental setups with potted plants. Here we describe the successful development of an acute 12-well plate phytotoxicity assay for the PSII herbicide Diuron using isolated Halophila ovalis leaves. Fluorescence images demonstrated Diuron affected the entire leaf surface evenly and responses were not influenced by isolating leaves from the plant. The optimum exposure duration was 24 h, by which time the inhibition of effective quantum yield of PSII (∆F/F(m)') was highest and no deterioration of photosystems was evident in control leaves. The inhibition of ∆F/F(m)' by Diuron in isolated H. ovalis leaves was identical to both potted and hydroponically grown plants (with leaves remaining attached to rhizomes), indicating similar reductions in photosynthetic activity in these acute well-plate assays. The sensitivity of the assay was not influenced by irradiance (range tested 40 to 400 μmol photons m(-2) s(-1)). High irradiance, however, caused photo-oxidative stress in H. ovalis and this generally impacted in an additive or sub-additive way with Diuron to damage PSII. The bioassay using isolated leaves is more rapid, uses far less biological material and does not rely on specialised aquarium facilities in comparison with assays using potted plants. The development and validation of this sensitive bioassay will be useful to reliably screen and monitor the phytotoxicity of existing and emerging PSII herbicides and contribute to risk assessments and water quality guideline development in the future.
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Affiliation(s)
- Adam D. Wilkinson
- College of Marine and Environmental Sciences, James Cook University, Townsville, Queensland, Australia
- Australian Institute of Marine Science, Townsville, Queensland, Australia
| | - Catherine J. Collier
- College of Marine and Environmental Sciences, James Cook University, Townsville, Queensland, Australia
- Centre for Tropical Water & Aquatic Ecosystem Research (TropWATER), James Cook University, Cairns, Queensland, Australia
| | - Florita Flores
- Australian Institute of Marine Science, Townsville, Queensland, Australia
| | - Phil Mercurio
- Australian Institute of Marine Science, Townsville, Queensland, Australia
- School of Medicine, University of Queensland and National Research Centre for Environmental Toxicology, Coopers Plains, Queensland, Australia
| | - Jake O’Brien
- School of Medicine, University of Queensland and National Research Centre for Environmental Toxicology, Coopers Plains, Queensland, Australia
| | - Peter J. Ralph
- Plant Functional Biology and Climate Change Cluster (C3), University of Technology, Sydney, New South Wales, Australia
| | - Andrew P. Negri
- Australian Institute of Marine Science, Townsville, Queensland, Australia
- * E-mail:
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12
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Scoma A, Durante L, Bertin L, Fava F. Acclimation to hypoxia in Chlamydomonas reinhardtii: can biophotolysis be the major trigger for long-term H2 production? New Phytol 2014; 204:890-900. [PMID: 25103459 DOI: 10.1111/nph.12964] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/2014] [Accepted: 07/04/2014] [Indexed: 05/10/2023]
Abstract
In anaerobiosis, the microalga Chlamydomonas reinhardtii is able to produce H2 gas. Electrons mainly derive from mobilization of internal reserves or from water through biophotolysis. However, the exact mechanisms triggering this process are still unclear. Our hypothesis was that, once a proper redox state has been achieved, H2 production is eventually observed. To avoid nutrient depletion, which would result in enhanced fermentative pathways, we aimed to induce long-lasting H2 production solely through a photosynthesis : respiration equilibrium. Thus, growing cells were incubated in Tris Acetate Phosphate (TAP) medium under low light and high chlorophyll content. After a 250-h acclimation phase, a 350-h H2 production phase was observed. The light-to-H2 conversion efficiency was comparable to that given in some reports operating under sulphur starvation. Electron sources were found to be water, through biophotolysis, and proteins, particularly through photofermentation. Nonetheless, a substantial contribution from acetate could not be ruled out. In addition, photosystem II (PSII) inhibition by 3-(3,4-dichlorophenyl)-1,1-dimethylurea (DCMU) showed that it actively contributed to maintaining a redox balance during cell acclimation. In appropriate conditions, PSII may represent the major source of reducing power to feed the H2 evolution process, by inducing and maintaining an ideal excess of reducing power.
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Affiliation(s)
- Alberto Scoma
- Department of Civil, Chemical, Environmental and Materials Engineering (DICAM), School of Engineering and Architecture, Alma Mater Studiorum, University of Bologna, Via U. Terracini 28, I-40131, Bologna, Italy
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13
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Magnucka EG, Pietr SJ, Kozubek A, Zarnowski R. Various effects of the photosystem II--inhibiting herbicides on 5-n-alkylresorcinol accumulation in rye seedlings. Pestic Biochem Physiol 2014; 116:56-62. [PMID: 25454521 DOI: 10.1016/j.pestbp.2014.09.015] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/05/2014] [Revised: 08/05/2014] [Accepted: 09/29/2014] [Indexed: 06/04/2023]
Abstract
The effect of three PSII-inhibiting herbicides, lenacil, linuron, and pyrazon, on the accumulation of 5-n-alkylresorcinols in rye seedlings (Secale cereale L.) grown under various light and thermal conditions was studied. All used chemicals increased resorcinolic lipid content in both green and etiolated plants grown at 29 °C. At 22 °C pyrazon and lenacil decreased the content of alkylresorcinols in plants kept in the darkness and increased their amount in the light-grown seedlings. In turn, level of resorcinolic lipids was decreased by linuron in both etiolated and green plants. At the lowest tested temperature lenacil enhanced production of alkylresorcinols only in etiolated rye seedlings, whereas the light-independent stimulatory action of pyrazon on alkylresorcinol accumulation in rye grown at 15 °C was observed. Additionally, only the latter did not exert a negative effect on rye seedling growth under any of tested conditions. Compared with respective controls, the herbicides used also markedly modified the qualitative pattern of resorcinolic homologs. Interestingly, the observed changes generally favored the enhanced antifungal activity of these compounds. Our study provides novel information on the influence of PSII inhibitors on alkylresorcinol metabolism in rye seedlings. The unquestionable achievement of this work is the observation that low dose of pyrazon mainly stimulated both growth and alkylresorcinol synthesis in rye seedlings, a non-target plant. Moreover, our experimental work showed unambiguously that the observed pyrazon-driven accumulation and homolog pattern modification of alkylresorcinols dramatically improved the resistance of winter rye to infections caused by Rhizoctonia cerealis.
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Affiliation(s)
- Elżbieta G Magnucka
- Agricultural Microbiology Lab, Department of Plant Protection, Wroclaw University of Environmental and Life Sciences, Grunwaldzka 53, 50-375 Wroclaw, Poland.
| | - Stanisław J Pietr
- Agricultural Microbiology Lab, Department of Plant Protection, Wroclaw University of Environmental and Life Sciences, Grunwaldzka 53, 50-375 Wroclaw, Poland
| | - Arkadiusz Kozubek
- Lipids and Liposomes Lab, Faculty of Biotechnology, University of Wroclaw, F. Joliot-Curie 14a, 50-383 Wroclaw, Poland
| | - Robert Zarnowski
- Department of Medicine, Section of Infectious Diseases, University of Wisconsin-Madison, 4125 Microbial Sciences Building, 1550 Linden Dr., Madison, WI 53706, USA
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14
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Karacan MS, Zharmukhamedov SK, Mamaş S, Kupriyanova EV, Shitov AV, Klimov VV, Özbek N, Özmen Ü, Gündüzalp A, Schmitt FJ, Karacan N, Friedrich T, Los DA, Carpentier R, Allakhverdiev SI. Screening of novel chemical compounds as possible inhibitors of carbonic anhydrase and photosynthetic activity of photosystem II. J Photochem Photobiol B 2014; 137:156-67. [PMID: 24418071 DOI: 10.1016/j.jphotobiol.2013.12.002] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/27/2013] [Accepted: 12/05/2013] [Indexed: 12/28/2022]
Abstract
Thirty novel chemical compounds were designed and synthesized expecting that they would be possible inhibitors. From this number eleven were organic bases, twenty-four were their organic derivatives and fourteen were metal complexes. Screening of these chemicals by their action on photosynthetic electron transfer (PET) and carbonic anhydrase (CA) activity (CAA) of photosystem II (PSII), α-CA, as well as β-CA was done. Several groups were revealed among them. Some of them are capable to suppress either one, two, three, or even all of the measured activities. As example, one of the Cu(II)-phenyl sulfonylhydrazone complexes (compound 25) suppresses CAA of α-CA by 88%, CAA of β-CA by 100% inhibition; CAA of PSII by 100% and the PSII photosynthetic activity by 66.2%. The Schiff base compounds (12, 15) and Cu(II)-phenyl sulfonylhydrazone complexes (25, 26) inhibited the CAA and PET of PSII significantly. The obtained data indicate that the PSII donor side is a target of the inhibitory action of these agents. Some physico- or electrochemical properties such as diffusion coefficient, number of transferred electrons, peak potential and heterogeneous standard rate constants of the compounds were determined in nonaqueous media. pKa values were also determined in nonaqueous and aqueous media. Availability in the studied group of novel chemical agents possessing different inhibitory activity allow in future to isolate the "active part" in the structure of the inhibitors responsible for different inhibitory mechanisms, as well as to determine the influence of side substituters on its inhibitory efficiency.
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Affiliation(s)
- Mehmet Sayım Karacan
- Gazi University, Science Faculty, Department of Chemistry, 06500 Ankara, Turkey.
| | - Sergei K Zharmukhamedov
- Institute of Basic Biological Problems, Russian Academy of Sciences, Institutskaya Street 2, Pushchino, Moscow Region 142290, Russia
| | - Serhat Mamaş
- Gazi University, Science Faculty, Department of Chemistry, 06500 Ankara, Turkey
| | - Elena V Kupriyanova
- Institute of Plant Physiology, Russian Academy of Sciences, Botanicheskaya Street 35, Moscow 127276, Russia
| | - Alexandr V Shitov
- Institute of Basic Biological Problems, Russian Academy of Sciences, Institutskaya Street 2, Pushchino, Moscow Region 142290, Russia
| | - Vyacheslav V Klimov
- Institute of Basic Biological Problems, Russian Academy of Sciences, Institutskaya Street 2, Pushchino, Moscow Region 142290, Russia
| | - Neslihan Özbek
- Ahi Evran University, Dept. of Primary Educ. Fac. Of Educ., 40100 Kırsehir, Turkey
| | - Ümmühan Özmen
- Gazi University, Science Faculty, Department of Chemistry, 06500 Ankara, Turkey
| | - Ayla Gündüzalp
- Gazi University, Science Faculty, Department of Chemistry, 06500 Ankara, Turkey
| | - Franz-Josef Schmitt
- Technical University of Berlin, Institute of Chemistry Sekr. PC 14, Max-Volmer-Laboratory of Biophysical Chemistry, Straβe des 17. Juni 135, D-10623 Berlin, Germany
| | - Nurcan Karacan
- Gazi University, Science Faculty, Department of Chemistry, 06500 Ankara, Turkey
| | - Thomas Friedrich
- Technical University of Berlin, Institute of Chemistry Sekr. PC 14, Max-Volmer-Laboratory of Biophysical Chemistry, Straβe des 17. Juni 135, D-10623 Berlin, Germany
| | - Dmitry A Los
- Institute of Plant Physiology, Russian Academy of Sciences, Botanicheskaya Street 35, Moscow 127276, Russia
| | - Robert Carpentier
- Department de Chimie, Biochimie et Physique, Université du Quebec à Trois Rivières, 3351 Boulevard des Forges, C.P. 500, Québec G9A 5H7, Canada
| | - Suleyman I Allakhverdiev
- Institute of Basic Biological Problems, Russian Academy of Sciences, Institutskaya Street 2, Pushchino, Moscow Region 142290, Russia; Institute of Plant Physiology, Russian Academy of Sciences, Botanicheskaya Street 35, Moscow 127276, Russia.
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15
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Baxter L, Brain R, Rodriguez-Gil JL, Hosmer A, Solomon K, Hanson M. Response of the green alga Oophila sp., a salamander endosymbiont, to a PSII-inhibitor under laboratory conditions. Environ Toxicol Chem 2014; 33:1858-1864. [PMID: 24782078 DOI: 10.1002/etc.2629] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/04/2014] [Revised: 03/20/2014] [Accepted: 04/28/2014] [Indexed: 06/03/2023]
Abstract
In a rare example of autotroph-vertebrate endosymbiosis, eggs of the yellow-spotted salamander (Ambystoma maculatum) are colonized by a green alga (Oophila sp.) that significantly enhances salamander development. Previous studies have demonstrated the potential for impacts to the salamander embryo when growth of the algae is impaired by exposure to herbicides. To further investigate this relationship, the authors characterized the response of the symbiotic algae (Oophila sp.) alone to the photosystem II (PSII) inhibitor atrazine under controlled laboratory conditions. After extraction of the alga from A. maculatum eggs and optimization of culturing conditions, 4 toxicity assays (96 h each) were conducted. Recovery of the algal population was also assessed after a further 96 h in untreated media. Average median effective concentration (EC50) values of 123 µg L(-1) (PSII yield), 169 µg L(-1) (optical density), and 299 µg L(-1) (growth rate) were obtained after the 96-h exposure. Full recovery of exposed algal populations after 96 h in untreated media was observed for all endpoints, except for optical density at the greatest concentration tested (300 µg L(-1) ). Our results show that, under laboratory conditions, Oophila sp. is generally less sensitive to atrazine than standard test species. Although conditions of growth in standard toxicity tests are not identical to those in the natural environment, these results provide an understanding of the tolerance of this alga to PSII inhibitors as compared with other species.
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Affiliation(s)
- Leilan Baxter
- Centre for Toxicology, University of Guelph, Guelph, Ontario, Canada
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16
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Varejão JOS, Barbosa LCA, Varejão EVV, Maltha CRA, King-Díaz B, Lotina-Hennsen B. Cyclopent-4-ene-1,3-diones: a new class of herbicides acting as potent photosynthesis inhibitors. J Agric Food Chem 2014; 62:5772-5780. [PMID: 24912105 DOI: 10.1021/jf5014605] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
In a recent paper, we reported the synthesis and photosynthesis-inhibitory activity of a series of analogues of rubrolides. From quantitative structure-activity relationship (QSAR) studies, we found that the most efficient compounds are those having higher ability to accept electrons. On the basis of those findings, we directed our effort to synthesize new analogues bearing a strong electron-withdrawing group (nitro) in the benzylidene ring and evaluate their effects on photosynthesis. However, the employed synthetic approach led to novel cyclopent-4-ene-1,3-diones as major products. Here, we report the synthesis and mechanism of action of such cyclopent-4-ene-1,3-diones as a new class of photosynthesis inhibitors. These compounds block the electron transport at the QB level by interacting at the D1 protein at the reducing side of Photosystem II and act as Hill reaction inhibitors, with higher activity than the corresponding rubrolides. To the best of our knowledge, this is the first report on the photosynthesis inhibitory activity of cyclopentenediones.
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Affiliation(s)
- Jodieh O S Varejão
- Department of Chemistry, Federal University of Viçosa , Avenida Peter Henry Rolfs, s/n, 36570-000 Viçosa, Minas Gerais, Brazil
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17
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Thiel H, Varrelmann M. Identification of a new PSII target site psbA mutation leading to D1 amino acid Leu218 Val exchange in the Chenopodium album D1 protein and comparison to cross-resistance profiles of known modifications at positions 251 and 264. Pest Manag Sci 2014; 70:278-285. [PMID: 23576399 DOI: 10.1002/ps.3556] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/17/2012] [Revised: 03/20/2013] [Accepted: 04/09/2013] [Indexed: 06/02/2023]
Abstract
BACKGROUND Resistance of Chenopodium album to triazinones and triazines can be caused by two amino acid exchanges, serine-264-glycine (Ser(264) Gly) and alanine-251-valine (Ala(251) Val), in the chloroplast D1 protein. This paper describes the identification of a biotype with a leucine-218-valine (Leu(218) Val) switch found in German sugar beet fields with unsatisfactory weed control. A greenhouse experiment has been performed to compare the resistance profile of the newly identified biotype with biotypes that carry the Ser(264) Gly and Ala(251) Val mutations. RESULTS Application rate-response curves obtained from the greenhouse experiment showed that the Leu(218) Val exchange induced significant resistance against the triazinones but not against terbuthylazine. The level of resistance against the triazinones was higher in the Ser(264) Gly and Ala(251) Val biotypes compared with the Leu(218) Val biotype. All biotypes tested were more resistant to metribuzin than to metamitron. Following terbuthylazine treatment, Ser264 Gly displayed a high level of resistance, Ala(251) Val showed moderate resistance. A PCR-RFLP assay for Ser(264) Gly has been extended to include detection of Ala251 Val and Leu(218) Val mutations. CONCLUSION The D1 Leu(218) Val substitution in C. album confers significant resistance to triazinones. This suggests that Leu(218) Val is involved in the binding of triazinones. First establishment of the resistance profiles of the three psbA mutations suggests that these mutations have been independently selected.
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Affiliation(s)
- Heike Thiel
- Institute of Sugar Beet Research, Department of Phytopathology, Holtenser Landstrasse 77, D-37079, Göttingen, Germany
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18
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Cutulle MA, Armel GR, Brosnan JT, Best MD, Kopsell DA, Bruce BD, Bostic HE, Layton DS. Synthesis and evaluation of heterocyclic analogues of bromoxynil. J Agric Food Chem 2014; 62:329-36. [PMID: 24354444 DOI: 10.1021/jf404209d] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
One attractive strategy to discover more active and/or crop-selective herbicides is to make structural changes to currently registered compounds. This strategy is especially appealing for those compounds with limited herbicide resistance and whose chemistry is accompanied with transgenic tools to enable herbicide tolerance in crop plants. Bromoxynil is a photosystem II (PSII) inhibitor registered for control of broadleaf weeds in several agronomic and specialty crops. Recently at the University of Tennessee-Knoxville several analogues of bromoxynil were synthesized including a previously synthesized pyridine (2,6-dibromo-5-hydroxypyridine-2-carbonitrile sodium salt), a novel pyrimidine (4,6-dibromo-5-hydroxypyrimidine-2-carbonitrile sodium salt), and a novel pyridine N-oxide (2,6-dibromo-1-oxidopyridin-1-ium-4-carbonitrile). These new analogues of bromoxynil were also evaluated for their herbicidal activity on soybean (Glycine max), cotton (Gossypium hirsutum), redroot pigweed (Amaranthus retroflexus), velvetleaf (Abutilon theophrasti), large crabgrass (Digitaria sanguinalis), and pitted morningglory ( Ipomoea lacunose ) when applied at 0.28 kg ha(-1). A second study was conducted on a glyphosate-resistant weed (Amaranthus palmeri) with the compounds being applied at 0.56 kg ha(-1). Although all compounds were believed to inhibit PSII by binding in the quinone binding pocket of D1, the pyridine and pyridine-N-oxide analogues were clearly more potent than bromoxynil on Amaranthus retroflexus. However, application of the pyrimidine herbicide resulted in the least injury to all species tested. These variations in efficacy were investigated using molecular docking simulations, which indicate that the pyridine analogue may form a stronger hydrogen bond in the pocket of the D1 protein than the original bromoxynil. A pyridine analogue was able to control the glyphosate-resistant Amaranthus palmeri with >80% efficacy. The pyridine analogues of bromoxynil showed potential to have a different weed control spectrum compared to bromoxynil. A pyridine analogue of bromoxynil synthesized in this research controlled several weed species greater than bromoxynil itself, potentially due to enhanced binding within the PSII binding pocket. Future research should compare this analogue to bromoxynil using optimized formulations at higher application rates.
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Affiliation(s)
- Matthew A Cutulle
- Department of Plant Sciences, University of Tennessee , Knoxville, Tennessee 37996, United States
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Abstract
Photosynthetic organisms and isolated photosystems are of interest for technical applications. In nature, photosynthetic electron transport has to work efficiently in contrasting environments such as shade and full sunlight at noon. Photosynthetic electron transport is regulated on many levels, starting with the energy transfer processes in antenna and ending with how reducing power is ultimately partitioned. This review starts by explaining how light energy can be dissipated or distributed by the various mechanisms of non-photochemical quenching, including thermal dissipation and state transitions, and how these processes influence photoinhibition of photosystem II (PSII). Furthermore, we will highlight the importance of the various alternative electron transport pathways, including the use of oxygen as the terminal electron acceptor and cyclic flow around photosystem I (PSI), the latter which seem particularly relevant to preventing photoinhibition of photosystem I. The control of excitation pressure in combination with the partitioning of reducing power influences the light-dependent formation of reactive oxygen species in PSII and in PSI, which may be a very important consideration to any artificial photosynthetic system or technical device using photosynthetic organisms.
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Nath K, Poudyal RS, Eom JS, Park YS, Zulfugarov IS, Mishra SR, Tovuu A, Ryoo N, Yoon HS, Nam HG, An G, Jeon JS, Lee CH. Loss-of-function of OsSTN8 suppresses the photosystem II core protein phosphorylation and interferes with the photosystem II repair mechanism in rice (Oryza sativa). Plant J 2013; 76:675-86. [PMID: 24103067 DOI: 10.1111/tpj.12331] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/03/2013] [Revised: 08/07/2013] [Accepted: 09/02/2013] [Indexed: 05/10/2023]
Abstract
STN8 kinase is involved in photosystem II (PSII) core protein phosphorylation (PCPP). To examine the role of PCPP in PSII repair during high light (HL) illumination, we characterized a T-DNA insertional knockout mutant of the rice (Oryza sativa) STN8 gene. In this osstn8 mutant, PCPP was significantly suppressed, and the grana were thin and elongated. Upon HL illumination, PSII was strongly inactivated in the mutants, but the D1 protein was degraded more slowly than in wild-type, and mobilization of the PSII supercomplexes from the grana to the stromal lamellae for repair was also suppressed. In addition, higher accumulation of reactive oxygen species and preferential oxidation of PSII reaction center core proteins in thylakoid membranes were observed in the mutants during HL illumination. Taken together, our current data show that the absence of STN8 is sufficient to abolish PCPP in osstn8 mutants and to produce all of the phenotypes observed in the double mutant of Arabidopsis, indicating the essential role of STN8-mediated PCPP in PSII repair.
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Affiliation(s)
- Krishna Nath
- Department of Molecular Biology, Pusan National University, Busan, 609-735, Korea; Department of New Biology, Daegu Gyeongbuk Institute of Science and Technology, Daegu, 711-873, Korea
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Prosser RS, Brain RA, Hosmer AJ, Solomon KR, Hanson ML. Assessing sensitivity and recovery of field-collected periphyton acutely exposed to atrazine using PSII inhibition under laboratory conditions. Ecotoxicology 2013; 22:1367-1383. [PMID: 24043588 DOI: 10.1007/s10646-013-1123-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 08/28/2013] [Indexed: 06/02/2023]
Abstract
Periphyton communities are an integral component of freshwater ecosystems and the desire to include data from toxicity testing with these organisms for ecological risk assessment is growing. This study developed sampling, storage, and exposure methods for the consistent and effective characterization of acute response and recovery of field-derived periphyton to photosystem II (PSII) inhibiting herbicides, particularly atrazine. Pulse amplitude modulated fluorometry was used to assess PSII quantum yield. For the method development phase, periphyton samples were collected from lotic and lentic systems in the Guelph, Ontario, Canada area during the summer of 2011. Following method development, native periphyton communities from three agricultural streams from the midwestern U.S. were sampled and exposed to atrazine (10-320 μg/L) and assessed for inhibition of PSII quantum yield (from 2 up to 24 h) and subsequent recovery upon cessation of exposure (up to 48 h post-exposure). Sensitivity to atrazine (EC10 and EC50 values) varied slightly (typically less than twofold difference) by site, date of sampling, and exposure interval. Only the highest initial test concentrations (160 or 320 μg/L) demonstrated greater than ~5% inhibition at 48 h post-exposure; however all other test concentrations recovered to within 5% of control levels, typically within 24 h. The rapid physiological recovery of periphyton communities upon atrazine removal supports the conclusion that acute exposure will not likely result in significant or sustained impacts on either structure or function of periphyton in lotic ecosystems. For ecological risk assessment, this suggests the current approach of relying on direct effects data for the most sensitive single species alone may result in overly conservative estimates of potential effects, especially for complex communities of primary producers.
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Affiliation(s)
- Ryan S Prosser
- School of Environmental Sciences, University of Guelph, Guelph, ON, Canada,
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Booij P, Sjollema SB, Leonards PEG, de Voogt P, Stroomberg GJ, Vethaak AD, Lamoree MH. Extraction tools for identification of chemical contaminants in estuarine and coastal waters to determine toxic pressure on primary producers. Chemosphere 2013; 93:107-114. [PMID: 23751123 DOI: 10.1016/j.chemosphere.2013.04.095] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2012] [Revised: 04/24/2013] [Accepted: 04/29/2013] [Indexed: 06/02/2023]
Abstract
The extent to which chemical stressors affect primary producers in estuarine and coastal waters is largely unknown. However, given the large number of legacy pollutants and chemicals of emerging concern present in the environment, this is an important and relevant issue that requires further study. The purpose of our study was to extract and identify compounds which are inhibitors of photosystem II activity in microalgae from estuarine and coastal waters. Field sampling was conducted in the Western Scheldt estuary (Hansweert, The Netherlands). We compared four different commonly used extraction methods: passive sampling with silicone rubber sheets, polar organic integrative samplers (POCIS) and spot water sampling using two different solid phase extraction (SPE) cartridges. Toxic effects of extracts prepared from spot water samples and passive samplers were determined in the Pulse Amplitude Modulation (PAM) fluorometry bioassay. With target chemical analysis using LC-MS and GC-MS, a set of PAHs, PCBs and pesticides was determined in field samples. These compound classes are listed as priority substances for the marine environment by the OSPAR convention. In addition, recovery experiments with both SPE cartridges were performed to evaluate the extraction suitability of these methods. Passive sampling using silicone rubber sheets and POCIS can be applied to determine compounds with different structures and polarities for further identification and determination of toxic pressure on primary producers. The added value of SPE lies in its suitability for quantitative analysis; calibration of passive samplers still needs further investigation for quantification of field concentrations of contaminants.
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Affiliation(s)
- Petra Booij
- Institute for Environmental Studies, VU University, De Boelelaan 1087, 1081 HV Amsterdam, The Netherlands.
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Belatik A, Hotchandani S, Carpentier R. Inhibition of the water oxidizing complex of photosystem II and the reoxidation of the quinone acceptor QA- by Pb2+. PLoS One 2013; 8:e68142. [PMID: 23861859 PMCID: PMC3701646 DOI: 10.1371/journal.pone.0068142] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2013] [Accepted: 05/24/2013] [Indexed: 11/28/2022] Open
Abstract
The action of the environmental toxic Pb(2+) on photosynthetic electron transport was studied in thylakoid membranes isolated from spinach leaves. Fluorescence and thermoluminescence techniques were performed in order to determine the mode of Pb(2+) action in photosystem II (PSII). The invariance of fluorescence characteristics of chlorophyll a (Chl a) and magnesium tetraphenylporphyrin (MgTPP), a molecule structurally analogous to Chl a, in the presence of Pb(2+) confirms that Pb cation does not interact directly with chlorophyll molecules in PSII. The results show that Pb interacts with the water oxidation complex thus perturbing charge recombination between the quinone acceptors of PSII and the S2 state of the Mn4Ca cluster. Electron transfer between the quinone acceptors QA and QB is also greatly retarded in the presence of Pb(2+). This is proposed to be owing to a transmembrane modification of the acceptor side of the photosystem.
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Affiliation(s)
- Ahmed Belatik
- Groupe de Recherche en Biologie Végétale, Université du Québec à Trois-Rivières, Trois-Rivières, Québec, Canada
| | - Surat Hotchandani
- Groupe de Recherche en Biologie Végétale, Université du Québec à Trois-Rivières, Trois-Rivières, Québec, Canada
| | - Robert Carpentier
- Groupe de Recherche en Biologie Végétale, Université du Québec à Trois-Rivières, Trois-Rivières, Québec, Canada
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Shibaeva TG, Markovskaia EF. [Growth and development of cucumber Cucumis sativus L. in the prereproductive period under long photoperiods]. ACTA ACUST UNITED AC 2013; 44:101-9. [PMID: 23785847 DOI: 10.7868/s0475145013020092] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
When plants are grown in a greenhouse, an increase in the photoperiod, as well as continuous lighting, is one of the ways to improve plant productivity and energy savings. However, a number of crops under long photoperiods develop signs of light damage to leaves, and productivity is reduced. We studied the effect of the photoperiod (8, 12, 16, 20, and 24 h) and photon flux densities (60, 120, and 160 micromol/m2 with PAR) on cucumber plants Cucumis sativus L. in a prereproductive period. We show that the response of the cucumber plants to a photoperiod duration of more than 20 h, including continuous lighting, depending on the plant age and lighting conditions, may include epinastic reaction of the leaves, activation of a mechanism of nonphotochemical chlorophyll fluorescence quenching, and/or reversible photoinhibition of a reaction center of photosystem II, development of reversible chlorosis, reduction of a light-harvesting complex, and increase in the content of carotenoids. Reaction of immature and virginile plants to long photoperiods was different, which highlights the need for experimental separation of the prereproductive period of development in terms of age states and consideration of this when preparing programs of cultivation.
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Millaleo R, Reyes-Díaz M, Alberdi M, Ivanov AG, Krol M, Hüner NPA. Excess manganese differentially inhibits photosystem I versus II in Arabidopsis thaliana. J Exp Bot 2013; 64:343-54. [PMID: 23183256 PMCID: PMC3528040 DOI: 10.1093/jxb/ers339] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
The effects of exposure to increasing manganese concentrations (50-1500 µM) from the start of the experiment on the functional performance of photosystem II (PSII) and photosystem I (PSI) and photosynthetic apparatus composition of Arabidopsis thaliana were compared. In agreement with earlier studies, excess Mn caused minimal changes in the PSII photochemical efficiency measured as F(v)/F(m), although the characteristic peak temperature of the S(2/3)Q(B) (-) charge recombinations was shifted to lower temperatures at the highest Mn concentration. SDS-PAGE and immunoblot analyses also did not exhibit any significant change in the relative abundance of PSII-associated polypeptides: PSII reaction centre protein D1, Lhcb1 (major light-harvesting protein of LHCII complex), and PsbO (OEC33, a 33 kDa protein of the oxygen-evolving complex). In addition, the abundance of Rubisco also did not change with Mn treatments. However, plants grown under excess Mn exhibited increased susceptibility to PSII photoinhibition. In contrast, in vivo measurements of the redox transients of PSI reaction centre (P700) showed a considerable gradual decrease in the extent of P700 photooxidation (P700(+)) under increased Mn concentrations compared to control. This was accompanied by a slower rate of P700(+) re-reduction indicating a downregulation of the PSI-dependent cyclic electron flow. The abundance of PSI reaction centre polypeptides (PsaA and PsaB) in plants under the highest Mn concentration was also significantly lower compared to the control. The results demonstrate for the first time that PSI is the major target of Mn toxicity within the photosynthetic apparatus of Arabidopsis plants. The possible involvement mechanisms of Mn toxicity targeting specifically PSI are discussed.
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Affiliation(s)
- R. Millaleo
- Programa de Doctorado en Ciencias de Recursos Naturales, Universidad de La Frontera, Temuco, Chile
| | - M. Reyes-Díaz
- Departamento de Ciencias Químicas y Recursos Naturales; Facultad de Ingeniería, Ciencias y Administración, Universidad de La Frontera,Temuco, Chile
- Center of Plant, Soil Interaction and Natural Resources Biotechnology, Scientific and Technological Bioresource Nucleus (BIOREN-UFRO), Universidad de La Frontera, Temuco, Chile
| | - M. Alberdi
- Departamento de Ciencias Químicas y Recursos Naturales; Facultad de Ingeniería, Ciencias y Administración, Universidad de La Frontera,Temuco, Chile
- Center of Plant, Soil Interaction and Natural Resources Biotechnology, Scientific and Technological Bioresource Nucleus (BIOREN-UFRO), Universidad de La Frontera, Temuco, Chile
| | - A. G. Ivanov
- Department of Biology and The Biotron Centre for Experimental Climate Change Research, Western University, London, Ontario, N6A 5B7, Canada
| | - M. Krol
- Department of Biology and The Biotron Centre for Experimental Climate Change Research, Western University, London, Ontario, N6A 5B7, Canada
| | - N. P. A. Hüner
- Department of Biology and The Biotron Centre for Experimental Climate Change Research, Western University, London, Ontario, N6A 5B7, Canada
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Perreault F, Oukarroum A, Melegari SP, Matias WG, Popovic R. Polymer coating of copper oxide nanoparticles increases nanoparticles uptake and toxicity in the green alga Chlamydomonas reinhardtii. Chemosphere 2012; 87:1388-94. [PMID: 22445953 DOI: 10.1016/j.chemosphere.2012.02.046] [Citation(s) in RCA: 109] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2011] [Revised: 01/24/2012] [Accepted: 02/19/2012] [Indexed: 05/25/2023]
Abstract
Copper oxide nanoparticles (CuO NPs) are frequently used in a polymer-coated form, to be included in paints or fabrics for antimicrobial properties. Their application in antifouling paints may lead to the contamination of aquatic ecosystems. However, the toxicological risk of NPs in the environment is hard to evaluate due to a lack of knowledge on the mechanisms of NP interaction with biological systems. In this study, we investigated the effect of polymer coating on CuO NP toxicity in the green alga Chlamydomonas reinhardtii by comparing bare and polymer-coated CuO NPs prepared from the same CuO nanopowder. Both CuO NP suspensions were toxic to C. reinhardtii after 6 h treatment to concentrations of 0.005-0.04 g L(-1). Bare and polymer-coated CuO NPs induced a decrease of Photosystem II activity and the formation of reactive oxygen species. Polymer-coated CuO NP was found to be more toxic than the uncoated CuO NP. The higher toxicity of CS-CuO NP was mainly associated with the increased capacity of polymer-coated CuO NP to penetrate the cell compared to bare CuO NPs. These results indicates that the high toxicity of polymer-coated CuO NPs in algal cells results of intracellular interactions between NPs and the cellular system.
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Affiliation(s)
- François Perreault
- Department of Chemistry, University of Quebec in Montreal, Case Postal 8888, Succursale Centre-Ville, Montreal, QC, Canada H3C 3P8
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van Dam JW, Negri AP, Mueller JF, Altenburger R, Uthicke S. Additive pressures of elevated sea surface temperatures and herbicides on symbiont-bearing foraminifera. PLoS One 2012; 7:e33900. [PMID: 22439012 PMCID: PMC3306314 DOI: 10.1371/journal.pone.0033900] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2012] [Accepted: 02/20/2012] [Indexed: 11/18/2022] Open
Abstract
Elevated ocean temperatures and agrochemical pollution individually threaten inshore coral reefs, but these pressures are likely to occur simultaneously. Experiments were conducted to evaluate the combined effects of elevated temperature and the photosystem II (PSII) inhibiting herbicide diuron on several types of symbiotic algae (diatom, dinoflagellate or rhodophyte) of benthic foraminifera in hospite. Diuron was shown to evoke a direct effect on photosynthetic efficiency (reduced effective PSII quantum yield ΔF/F'(m)), while elevated temperatures (>30 °C, only 2 °C above current average summer temperatures) were observed to impact photosynthesis more indirectly by causing reductions in maximum PSII quantum yield (F(v)/F(m)), interpreted as photodamage. Additionally, elevated temperatures were shown to cause bleaching through loss of chlorophyll a in foraminifera hosting either diatoms or dinoflagellates. A significant linear correlation was found between reduced F(v)/F(m) and loss of chlorophyll a. In most cases, symbionts within foraminifera proved more sensitive to thermal stress in the presence of diuron (≥ 1 µg L(-1)). The mixture toxicity model of Independent Action (IA) described the combined effects of temperature and diuron on the photosystem of species hosting diatoms or dinoflagellates convincingly and in agreement with probabilistic statistics, so a response additive joint action can be assumed. We thus demonstrate that improving water quality can improve resilience of symbiotic phototrophs to projected increases in ocean temperatures. As IA described the observed combined effects from elevated temperature and diuron stress it may therefore be employed for prediction of untested mixtures and for assessing the efficacy of management measures.
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Affiliation(s)
- Joost W van Dam
- The University of Queensland, School of Biological Sciences, St Lucia, Australia.
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Perreault F, Matias MS, Oukarroum A, Matias WG, Popovic R. Okadaic acid inhibits cell growth and photosynthetic electron transport in the alga Dunaliella tertiolecta. Sci Total Environ 2012; 414:198-204. [PMID: 22134032 DOI: 10.1016/j.scitotenv.2011.10.045] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/18/2011] [Revised: 09/26/2011] [Accepted: 10/22/2011] [Indexed: 05/31/2023]
Abstract
Okadaic acid (OA), which is produced by several dinoflagellate species, is a phycotoxin known to induce a decrease of biomass production in phytoplankton. However, the mechanisms of OA cytotoxicity are still unknown in microalgae. In this study, we exposed the green microalga Dunaliella tertiolecta to OA concentrations of 0.05 to 0.5 μM in order to evaluate its effects on cell division, reactive oxygen species production and photosynthetic electron transport. After 72 h of treatment under continuous illumination, OA concentrations higher than 0.10 μM decreased culture cell density, induced oxidative stress and inhibited photosystem II electron transport capacity. OA effect in D. tertiolecta was strongly light dependent since no oxidative stress was observed when D. tertiolecta was exposed to OA in the dark. In the absence of light, the effect of OA on culture cell density and photosystem II activity was also significantly reduced. Therefore, light appears to have a significant role in the toxicity of OA in microalgae. Our results indicate that the site of OA interaction on photosynthetic electron transport is likely to be at the level of the plastoquinone pool, which can lead to photo-oxidative stress when light absorbed by the light-harvesting complex of photosystem II cannot be dissipated via photochemical pathways. These findings allowed for a better understanding of the mechanisms of OA toxicity in microalgae.
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Affiliation(s)
- François Perreault
- Department of Chemistry, Université du Québec à Montréal, 2101 Rue Jeanne Mance, Montréal, QC, Canada H2X 2J6
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Laviale M, Morin S, Créach A. Short term recovery of periphyton photosynthesis after pulse exposition to the photosystem II inhibitors atrazine and isoproturon. Chemosphere 2011; 84:731-4. [PMID: 21492903 DOI: 10.1016/j.chemosphere.2011.03.035] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2010] [Revised: 03/07/2011] [Accepted: 03/19/2011] [Indexed: 05/09/2023]
Abstract
Aquatic organisms are exposed to fluctuating concentrations of herbicides which contaminate rivers following their use for agricultural or domestic purposes. The development of sensitive bioanalytical tests enabling us not only to detect the effects of those pollutants but to take into account this pattern of exposure should improve the ecological relevance of river toxicity assessment. In this respect, the use of chlorophyll fluorescence measurements is a convenient way to probe the effect of photosystem II (PSII) inhibitors on primary producers. This study was devoted to validate the combined use of two fluorescence parameters, the effective and the optimal quantum yields of PSII photochemistry (Φ(PSII) and F(v)/F(m)), as reliable biomarkers of initial isoproturon (IPU) or atrazine (ATZ) toxicity to natural periphyton in a pulse exposition scenario. Φ(PSII) and F(v)/F(m) were regularly estimated during a 7 h-exposure to each pollutant (0-100 μM) and also later after being transferred in herbicide-free water (up to 36 h). Our results showed that IPU was more toxic than ATZ, but with effects reversible within 12 h. Moreover, these two similarly acting herbicides (i.e. same target site) presented contrasted short term recovery patterns, regarding the previous exposure duration.
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Krejci J, Ondruch V, Maly J, Stofik M, Krejcova D, Vranova H. High sensitivity biosensor measurement based on synchronous detection. J Photochem Photobiol B 2011; 102:192-199. [PMID: 21196122 DOI: 10.1016/j.jphotobiol.2010.12.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/06/2010] [Revised: 11/25/2010] [Accepted: 12/03/2010] [Indexed: 05/30/2023]
Abstract
The principle of synchronous detection (SD) has been applied to biosensor measurement. SD principle achieves significant increases in the signal to noise ratio, limit of detection and overall measurement robustness. Application of SD in biosensor measurement improves the analysis of the response and avoids the influence of interference/noise produced by stirring, electromagnetic effects and influence of parasitic currents. SD also enables the decomposition of signal to stimulation response and phenomena with long time of response. Second-order phenomena are identifiable in the signal. Linear statistical model was used to develop software for identification of the stimulation signal in the output current. SD was applied to the response signal of a Photosystem II complex (PSII) biosensor. PSII response to light stimulation follows first order kinetics. The inhibition kinetics of PSII has been studied. Kinetic constants of herbicide binding to PSII depend linearly on herbicide concentration and enable measurement of its concentration at low concentrations (linear range for diuron is 10⁻⁶ to 10⁻⁴ mM).
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Affiliation(s)
- J Krejci
- BVT Technologies a.s. Hudcova 78, CZ-612 00 Brno, Czech Republic.
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31
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Nijo N, Lundin B, Yoshioka M, Morita N, Yamamoto Y. Assay of photoinhibition and heat inhibition of photosystem II in higher plants. Methods Mol Biol 2011; 684:201-215. [PMID: 20960132 DOI: 10.1007/978-1-60761-925-3_17] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
When thylakoids of higher plant chloroplasts are exposed to excessive light or moderate heat stress, photosystem II reaction center-binding protein D1 is damaged. The photodamage of the D1 protein is caused by reactive oxygen species, mostly singlet oxygen, and also by endogenous cationic radicals generated by the photochemical reactions of photosystem II. Moreover, it was shown recently that the damage to the D1 protein by moderate heat stress is due to reactive oxygen species produced by lipid peroxidation near photosystem II. To maintain photosystem II activity, the oxidatively damaged D1 protein must be replaced by a newly synthesized copy, and thus degradation and removal of the photo- or heat-damaged D1 protein are essential for maintaining the viability of photosystem II. In this chapter, we describe the methods for assaying photoinhibition and heat inhibition of photosystem II in higher plant materials.
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Affiliation(s)
- Nobuyoshi Nijo
- Graduate School of Natural Science and Technology, Okayama University, Okayama, Japan
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Masojídek J, Souček P, Máchová J, Frolík J, Klem K, Malý J. Detection of photosynthetic herbicides: algal growth inhibition test vs. electrochemical photosystem II biosensor. Ecotoxicol Environ Saf 2011; 74:117-122. [PMID: 20828821 DOI: 10.1016/j.ecoenv.2010.08.028] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/24/2009] [Revised: 07/13/2009] [Accepted: 08/20/2010] [Indexed: 05/29/2023]
Abstract
We compared a novel PSII-biosensor assay with a standard algal growth inhibition test for detection of photosynthetic herbicides--diuron, atrazine and isoproturon in liquid samples. To evaluate the convenience and sensitivity, values of the parameters EC50 and LOD and the duration of assays were compared. The biosensor assay was made with an electrochemical biosensor toxicity analyser with immobilised Photosystem II (PSII) complex. Using the PSII-biosensor assay, higher sensitivity (LOD) to herbicides (10(-8)-10(-9)M) was achieved as compared to standard algal growth inhibition tests (about 10(-7)M). The results of both assays showed a good correlation as concerns their EC50 values while the interval of detectable concentrations is about twice wider for PSII-biosensor. A proposed measurement protocol includes the reference standard of phytotoxicity (RSP). The main advantage of the PSII-biosensor assay is that it can be completed in about 1h and is by 1-2 orders more sensitive than standard algal growth inhibition test, which takes 72 h.
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Affiliation(s)
- Jiří Masojídek
- Institute of Microbiology, Academy of Sciences of the Czech Republic, Opatovický mlýn, CZ-37981 Třeboň, Czech Republic.
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Porsbring T, Backhaus T, Johansson P, Kuylenstierna M, Blanck H. Mixture toxicity from photosystem II inhibitors on microalgal community succession is predictable by concentration addition. Environ Toxicol Chem 2010; 29:2806-13. [PMID: 20836067 DOI: 10.1002/etc.346] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/12/2010] [Revised: 04/16/2010] [Accepted: 07/21/2010] [Indexed: 05/11/2023]
Abstract
The typical pollution situation involves chemical mixtures, and assessing the risks of single chemicals one at a time is not sufficient. Concentration addition (CA) has been suggested as a predictive tool in mixture ecotoxicology. The accuracy of CA for mixtures of similarly acting chemicals has been demonstrated under relatively simple biological conditions in single-species tests. To consider the high diversity of interconnected species in ecosystems, one must evaluate CA on a community level of biological organization. We sampled marine periphyton communities from the west coast of Sweden and exposed them to photosystem II (PSII) inhibiting herbicides for 4 d in the SWIFT test, a semistatic, small-scale laboratory test. During this time, the communities went through an ecological succession, influenced by the toxicants in a concentration-dependent manner. Multidimensional scaling was used to assess similarities in the effects of two different sets of PSII inhibitors on pigment profiles, which reflects the taxonomic structure and the physiological status of the microalgal community. One mixture of structurally congeneric phenylureas and one mixture of non-congeneric PSII inhibitors were tested. All PSII inhibitors and their mixtures caused similar changes in the pigment profiles, demonstrating that they not only have a similar biochemical mechanism of action but also are similarly acting on a community level. Concentration addition accurately predicted the effects of both mixtures over the entire effect range. This demonstrates that chemical congenericity is not required for a high predictive power of CA. Instead, in perfect analogy to the situation in single-species tests, a similar mode of action is a sufficient prerequisite for a successful application of CA.
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Affiliation(s)
- Tobias Porsbring
- Department of Plant and Environmental Sciences, University of Gothenburg, Box 461, SE-40530 Göteborg, Sweden.
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Vermeirssen ELM, Hollender J, Bramaz N, van der Voet J, Escher BI. Linking toxicity in algal and bacterial assays with chemical analysis in passive samplers deployed in 21 treated sewage effluents. Environ Toxicol Chem 2010; 29:2575-2582. [PMID: 20853455 DOI: 10.1002/etc.311] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
A diverse mix of micropollutants, including pesticides, biocides, and pharmaceuticals, reaches the aquatic environment through treated sewage effluents. We sampled 21 final effluents with polar organic chemical integrative samplers (POCIS) and investigated to what extent chemical analyses of six photosystem II (PS-II) inhibitors and 12 other chemicals explain the toxic burdens quantified with two bioassays. Baseline toxicity equivalent concentrations (TEQ) were determined with a bacterial bioluminescence inhibition assay using Vibrio fischeri (baseline-TEQ(bacteria)) and by assessing toxicity on algal growth using Pseudokirchneriella subcapitata (baseline-TEQ(algae)). Inhibition PS-II was also determined with algae and expressed using diuron equivalent concentrations (DEQ(bio)). Concentrations of chemicals and toxicities varied appreciably between effluents, typically spanning two orders of magnitude. Across 21 independent effluents, a DEQ calculated by concentration addition of PS-II inhibitors (DEQ(chem)) proved a very good predictor of DEQ(bio); DEQ(chem) explained 65% of DEQ(bio). However, baseline-TEQ(bacteria,bio) correlated poorly with baseline-TEQ(algae,bio), because baseline-TEQ(algae) were strongly influenced by PS-II inhibitors. Using data on the 18 quantified compounds, and their estimated toxicities in the bacterial assay, we calculated a baseline-TEQ(bacteria,chem). With one exception, a site with a high load of diclofenac, less than 1% of baseline-TEQ(bacteria,bio) was explained by the analyzed chemicals. We conclude that for the analyses of final effluents, DEQ(bio) is a robust endpoint and useful screening tool for PS-II inhibitors; in the presence of herbicides, baseline-TEQ(bacteria,bio) proves a more robust measure of baseline toxicity than baseline-TEQ(algae,bio).
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Huang W, Zhang SB, Cao KF. Stimulation of cyclic electron flow during recovery after chilling-induced photoinhibition of PSII. Plant Cell Physiol 2010; 51:1922-8. [PMID: 20861006 DOI: 10.1093/pcp/pcq144] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
Although cyclic electron flow (CEF) is essential for repair of PSII, it is unclear whether the CEF is stimulated and what the role of stability of PSI is during the recovery. In order to explore these two questions, mature leaves of Dalbergia odorifera were treated with the chilling temperature of 4°C under a photosynthetic flux density (PFD) of 650 μmol m(-2) s(-1) for 2 h and then were transferred to 25°C under a PFD of 100 μmol m(-2) s(-1) for recovery. The maximum quantum yield of PSII (F(v)/F(m)), the maximum photo-oxidizable P700 (P(m)), the energy distribution in PSII and the redox state of P700 at 25°C under a PFD of 100 μmol m(-2) s(-1) were determined before and after chilling treatment and during subsequent recovery. We found that the CEF was significantly stimulated during the recovery after photodamage. There is a significant positive correlation between stimulation of CEF and photodamage of PSII during recovery. Our results indicated that CEF was significantly stimulated in order to enhance the synthesis of ATP for the fast repair of PSII. The stability of PSI activity favored the fast repair of PSII activity through stimulation of CEF.
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Affiliation(s)
- Wei Huang
- Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla, Yunnan 666303, PR China
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Thiel H, Kluth C, Varrelmann M. A new molecular method for the rapid detection of a metamitron-resistant target site in Chenopodium album. Pest Manag Sci 2010; 66:1011-1017. [PMID: 20730994 DOI: 10.1002/ps.1975] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
BACKGROUND Resistance to photosystem II inhibitors-triazines (atrazine) and triazinones (metamitron, metribuzin)-in Chenopodium album L. is caused by the serine 264 to glycine mutation in the D1 protein. This mutation has been detected in C. album collections from Belgium with unsatisfactory metamitron efficacy in the field and was confirmed in greenhouse resistance bioassays. Incomplete herbicide efficacy in practice can also be caused by reduced uptake due to environmental conditions. Hence, for reliable differentiation and resistance identification, a rapid method for mutation detection in the target gene psbA is required. RESULTS Dose-response curves obtained in herbicide greenhouse assays with metamitron-resistant and -susceptible reference biotypes showed that a dose of 2 L ha(-1) metamitron was suitable for discrimination. A psbA PCR-RFLP was developed, based on the presence of a FspBI restriction enzyme recognition site, covering D1 codon 264 in susceptible genotypes. A paper-based DNA extraction allowed direct processing of leaf samples already in the field. In order to detect the mutation even in mixed seed samples, a nested PCR-RFLP was also developed. CONCLUSION The method allows exhaustive surveys screening C. album leaf or seed samples for the occurrence of the D1 Ser264Gly mutation to confirm or disprove metamitron resistance in the case of unsatisfactory control.
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Affiliation(s)
- Heike Thiel
- Institute of Sugar Beet Research, Department of Phytopathology, Göttingen, Germany
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Knauer K, Leimgruber A, Hommen U, Knauert S. Co-tolerance of phytoplankton communities to photosynthesis II inhibitors. Aquat Toxicol 2010; 96:256-63. [PMID: 20004984 DOI: 10.1016/j.aquatox.2009.11.001] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/22/2009] [Revised: 10/31/2009] [Accepted: 11/03/2009] [Indexed: 05/10/2023]
Abstract
Natural variability in sensitivity and pollution induced community tolerance (PICT) to atrazine, isoproturon and diuron and a mixture of these three herbicides to natural algal assemblages in mesocosms was determined. The specificity of PICT was examined by evaluating co-tolerance pattern for these photosystem-II (PSII) inhibitors. Phytoplankton communities were constantly exposed to equipotent concentrations of atrazine, isoproturon, diuron namely the 30% hazard concentration (HC(30)) obtained from species sensitivity distributions and an equitoxic mixture (Sigma3 x 1/3 x HC(30) of each herbicide) for five weeks in outdoor mesocosms. Induction of tolerance to the various herbicides was investigated by photosynthetic efficiency measurements of the algal assemblages in short-term laboratory tests. The composition of the algal communities in the various treatments was determined and ordination techniques such as the principal component analysis (PCA) were applied to log-transformed data to compare the seasonal community structure development. Temporal variation in sensitivity of the control algal assemblage to atrazine and isoproturon, but less to diuron was observed. The results further demonstrated that the control communities were in general more sensitive than the treated ones over the whole period tested indicating an enhanced tolerance of pre-exposed phytoplankton in the mesocosms. Co-tolerance was also observed for atrazine pre-exposed algal community to isoproturon, however, not vise versa. A pre-exposure to diuron induced similar tolerance to all three herbicides. A pre-exposure to the mixture treatment also lead to tolerance to isoproturon and diuron, less to atrazine. Overall, the observed co-tolerance pattern indicates that co-tolerance was not comparable between the herbicides with strong similarity in their biochemical mode of action.
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Affiliation(s)
- Katja Knauer
- University of Basel, Program Sustainability Research, Basel, Switzerland.
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Murkowski A, Skórska E. Effect of (C6H5)3PbCl and (C6H5)3SnCl on delayed luminescence intensity, evolving oxygen and electron transport rate in photosystem II of Chlorella vulgaris. Bull Environ Contam Toxicol 2010; 84:157-160. [PMID: 19784804 DOI: 10.1007/s00128-009-9880-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2009] [Accepted: 09/17/2009] [Indexed: 05/28/2023]
Abstract
The effect of the organometallic compounds containing lead, (C6H5)3PbCl , and tin, (C6H5)3SnCl, on Chlorella green algae photosystem II was studied. Suspension of the algae treated with (C6H5)3SnCl at concentrations of 1.0 and 4.0 micromol dm(-3) for 22 h revealed a decrease in most physiological parameters studied, particularly in decasecond component of delayed chlorophyll luminescence, photosynthetic electron transport rate and diluted oxygen concentration, which implies an inhibition of photosynthetic electron transport as well as oxygen evolving system. On the other hand, (C6H5)3PbCl caused stronger inhibition than (C6H5)3SnCl, particularly in the higher concentration.
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Affiliation(s)
- Antoni Murkowski
- Department of Physics and Agrophysics, West Pomeranian University of Technology, Szczecin, Papieza Pawła VI no 3, 71-459, Szczecin, Poland
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Kuntzleman TS, Haddy A. Fluoride inhibition of photosystem II and the effect of removal of the PsbQ subunit. Photosynth Res 2009; 102:7-19. [PMID: 19633919 DOI: 10.1007/s11120-009-9469-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/19/2009] [Accepted: 07/06/2009] [Indexed: 05/28/2023]
Abstract
Photosystem II (PSII), the light-absorbing complex of photosynthesis that evolves oxygen, requires chloride for activation of the oxygen evolving complex (OEC). In this study, fluoride was characterized as an inhibitor of Cl(-)-activated oxygen evolution in higher plant PSII. It was confirmed to be primarily a competitive inhibitor in intact PSII, with Cl(-)-competitive inhibition constant K(i) = 2 mM and uncompetitive inhibition constant K'(1) = 79 mM. A pH dependence study showed that fluoride inhibition was more pronounced at lower pH values. In order to determine the location of the fluoride effect, PSII preparations lacking various amounts of the PsbQ subunit were prepared. The competitive F(-) inhibition constant and the Michaelis constant for Cl(-) activation increased with loss of the PsbQ subunit, while the uncompetitive F(-) inhibition constant was relatively insensitive to loss of PsbQ. The S(2) state EPR signals from PSII lacking PsbQ responded to Ca(2+) and Cl(-) removal and to F(-) treatment similar to intact PSII, with enhancement of the g = 4.1 signal and suppression of the multiline signal, but the effects were more pronounced in PSII lacking PsbQ. Together, these results support the interpretation that the PsbQ subunit has a role in retaining anions within the OEC.
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Affiliation(s)
- Thomas S Kuntzleman
- Department of Chemistry and Biochemistry, University of North Carolina at Greensboro, Greensboro, NC 27402, USA
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40
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Matorin DN, Osipov VA, Seĭfullina NK, Venediktov PS, Rubin AB. [Enhancement of methyl mercury toxicity on Chlorella vulgaris under light and cold stress]. Mikrobiologiia 2009; 78:362-368. [PMID: 19580160] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
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41
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Zhao Q, Liu S, Li Y, Wang Q. Design, synthesis, and biological activities of novel 2-cyanoacrylates containing oxazole, oxadiazole, or quinoline moieties. J Agric Food Chem 2009; 57:2849-2855. [PMID: 19271709 DOI: 10.1021/jf803632t] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
A series of novel 2-cyanoacrylates containing an oxazole, oxadiazole, or quinoline moiety were designed and synthesized, and their structures were characterized by (1)H NMR and elemental analysis (or high-resolution mass spectrometry). Their herbicidal activities against four weeds were evaluated, and the result indicated that some of the title compounds showed excellent herbicidal activities against rape and amaranth pigweed in postemergence treatment at a dose of 375 g/ha. Furthermore, most of these cyanoacrylates exhibited interesting plant growth regulatory activities.
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Affiliation(s)
- Qiqi Zhao
- State Key Laboratory of Elemento-Organic Chemistry, Research Institute of Elemento-Organic Chemistry, Nankai University, Tianjin 300071, People's Republic of China
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Knauert S, Dawo U, Hollender J, Hommen U, Knauer K. Effects of photosystem II inhibitors and their mixture on freshwater phytoplankton succession in outdoor mesocosms. Environ Toxicol Chem 2009; 28:836-845. [PMID: 19391680 DOI: 10.1897/08-135r.1] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/20/2008] [Accepted: 10/10/2008] [Indexed: 05/27/2023]
Abstract
Effects of three photosystem II inhibitors and of their mixture on a freshwater phytoplankton community were studied in outdoor mesocosms. Atrazine, isoproturon, and diuron were applied as 30% hazardous concentrations (HC30s) obtained from species-sensitivity distributions. Taking concentration addition into account, the mixture comprised one-third of the HC30 of each substance. Effects were investigated during a five-week period of constant concentrations and a five-month posttreatment period when the herbicides dissipated. Total abundance, species composition, and diversity and recovery of the community were evaluated. Ordination techniques, such as principal component analysis and principal response curve, were applied to compare the various treatments on the community level. The three herbicides stimulated comparable effects on total abundance and diversity of phytoplankton during the period of constant exposure because of the susceptibility of the dominant cryptophytes Chroomonas acuta and Cryptomonas erosa et ovata and the prasinophyte Nephroselmis cf. olivacea. Moreover, concentration addition described combined effects of atrazine, isoproturon, and diuron on total abundance and diversity in the constant-exposure period, because their mixture induced effects on abundance and diversity similar to those of the single substances. Principal component and principal response curve analyses revealed that the community structure of diuron- and isoproturon-treated phytoplankton recovered two weeks after constant exposure, which might be related to the fast dissipation of the phenylureas. Species compositions of mixture- and atrazine-treated communities were not comparable to that of the control community five months after the end of constant exposure. This might be explained by the slower dissipation of atrazine relative to the phenylureas and by differences in the species sensitivities, resulting in a different succession of phytoplankton.
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Affiliation(s)
- Stefanie Knauert
- Department of Environmental Sciences, University of Basel, Hebelstrasse 1, 4056 Basel, Switzerland.
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Sussman M, Mieog JC, Doyle J, Victor S, Willis BL, Bourne DG. Vibrio zinc-metalloprotease causes photoinactivation of coral endosymbionts and coral tissue lesions. PLoS One 2009; 4:e4511. [PMID: 19225559 PMCID: PMC2637982 DOI: 10.1371/journal.pone.0004511] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2008] [Accepted: 01/01/2009] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Coral diseases are emerging as a serious threat to coral reefs worldwide. Of nine coral infectious diseases, whose pathogens have been characterized, six are caused by agents from the family Vibrionacae, raising questions as to their origin and role in coral disease aetiology. METHODOLOGY/PRINCIPAL FINDINGS Here we report on a Vibrio zinc-metalloprotease causing rapid photoinactivation of susceptible Symbiodinium endosymbionts followed by lesions in coral tissue. Symbiodinium photosystem II inactivation was diagnosed by an imaging pulse amplitude modulation fluorometer in two bioassays, performed by exposing Symbiodinium cells and coral juveniles to non-inhibited and EDTA-inhibited supernatants derived from coral white syndrome pathogens. CONCLUSION/SIGNIFICANCE These findings demonstrate a common virulence factor from four phylogenetically related coral pathogens, suggesting that zinc-metalloproteases may play an important role in Vibrio pathogenicity in scleractinian corals.
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Affiliation(s)
- Meir Sussman
- ARC Centre of Excellence for Coral Reef Studies, and School of Marine and Tropical Biology, James Cook University, Townsville, Queensland, Australia.
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Khandelwal A, Elvitigala T, Ghosh B, Quatrano RS. Arabidopsis transcriptome reveals control circuits regulating redox homeostasis and the role of an AP2 transcription factor. Plant Physiol 2008; 148:2050-8. [PMID: 18829981 PMCID: PMC2593674 DOI: 10.1104/pp.108.128488] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/28/2008] [Accepted: 09/26/2008] [Indexed: 05/18/2023]
Abstract
Sensors and regulatory circuits that maintain redox homeostasis play a central role in adjusting plant metabolism and development to changing environmental conditions. We report here control networks in Arabidopsis (Arabidopsis thaliana) that respond to photosynthetic stress. We independently subjected Arabidopsis leaves to two commonly used photosystem II inhibitors: high light (HL) and 3-(3,4-dichlorophenyl)-1,1-dimethylurea (DCMU). Microarray analysis of expression patterns during the period of redox adjustment to these inhibitors reveals that 20% and 8% of the transcriptome are under HL and DCMU regulation, respectively. Approximately 6% comprise a subset of genes common to both perturbations, the redox responsive genes (RRGs). A redox network was generated in an attempt to identify genes whose expression is tightly coordinated during adjustment to homeostasis, using expression of these RRGs under HL conditions. Ten subnetworks were identified from the network. Hierarchal subclustering of subnetworks responding to the DCMU stress identified novel groups of genes that were tightly controlled while adjusting to homeostasis. Upstream analysis of the promoters of the genes in these clusters revealed different motifs for each subnetwork, including motifs that were previously identified with responses to other stresses, such as light, dehydration, or abscisic acid. Functional categorization of RRGs demonstrated involvement of genes in many metabolic pathways, including several families of transcription factors, especially those in the AP2 family. Using a T-DNA insertion in one AP2 transcription factor (redox-responsive transcription factor 1 [RRTF1]) from the RRGs, we showed that the genes predicted to be within the subnetwork containing RRTF1 were changed in this insertion line (Deltarrtf1). Furthermore, Deltarrtf1 showed greater sensitivity to photosynthetic stress compared to the wild type.
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Affiliation(s)
- Abha Khandelwal
- Department of Biology , Washington University, St. Louis, Missouri 63130, USA
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Pan X, Deng C, Zhang D, Wang J, Mu G, Chen Y. Toxic effects of amoxicillin on the photosystem II of Synechocystis sp. characterized by a variety of in vivo chlorophyll fluorescence tests. Aquat Toxicol 2008; 89:207-13. [PMID: 18718680 DOI: 10.1016/j.aquatox.2008.06.018] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/28/2007] [Revised: 06/20/2008] [Accepted: 06/25/2008] [Indexed: 05/15/2023]
Abstract
Amoxicillin is one of the widely used antibiotics of environmental concern. This study shows that amoxicillin has toxic effects on the photosynthesis of Synechocystis sp. Its inhibitory effects on photosystem II (PSII) of Synechocystis sp. were investigated by using a variety of in vivo chlorophyll fluorescence tests. The inhibitory effects of amoxicillin on PSII activity of Synechocystis sp. are concentration-dependent. Amoxicillin exposure leads to slowing down of electron transport on both donor side and acceptor side and causes accumulation of P680(+). Q(A)(-) reoxidation test revealed that amoxicillin hinders electron transfer from Q(A)(-) to Q(B)/Q(B)(-) and more Q(A)(-) is oxidized through S(2)(Q(A)Q(B))(-) charge recombination. Analysis of PSII heterogeneity demonstrated that an exposure to amoxicillin increases the proportion of inactive PSII (PSII(X)) centers and the proportion of PSII centers with small antenna (PSIIbeta). These changes finally result in deterioration of full photosynthesis performance.
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Affiliation(s)
- Xiangliang Pan
- Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumuqi, 830011, PR China
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Knauert S, Escher B, Singer H, Hollender J, Knauer K. Mixture toxicity of three photosystem II inhibitors (atrazine, isoproturon, and diuron) toward photosynthesis of freshwater phytoplankton studied in outdoor mesocosms. Environ Sci Technol 2008; 42:6424-6430. [PMID: 18800510 DOI: 10.1021/es072037q] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Mixture toxicity of three herbicides with the same mode of action was studied in a long-term outdoor mesocosm study. Photosynthetic activity of phytoplankton as the direct target site of the herbicides was chosen as physiological response parameter. The three photosystem II (PSII) inhibitors atrazine, isoproturon, and diuron were applied as 30% hazardous concentrations (HC30), which we derived from species sensitivity distributions calculated on the basis of EC50 growth inhibition data. The respective herbicide mixture comprised 1/3 of the HC30 of each herbicide. Short-term laboratory experiments revealed that the HC30 values corresponded to EC40 values when regarding photosynthetic activity as the response parameter. In the outdoor mesocosm experiment, effects of atrazine, isoproturon, diuron and their mixture on the photosynthetic activity of phytoplankton were investigated during a five-week period with constant exposure and a subsequent five-month postexposure period when the herbicides dissipated. The results demonstrated that mixture effects determined at the beginning of constant exposure can be described by concentration addition since the mixture elicited a phytotoxic effect comparable to the single herbicides. Declining effects on photosynthetic activity during the experiment might be explained by both a decrease in water herbicide concentrations and by the induction of community tolerance.
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Affiliation(s)
- Stefanie Knauert
- Department of Environmental Sciences, University of Basel, 4056 Basel, Switzerland.
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Vallotton N, Lambertus Eggen RI, Escher BI, Krayenbühl J, Chèvre N. Effect of pulse herbicidal exposure on scenedesmus vacuolatus: a comparison of two photosystem II inhibitors. Environ Toxicol Chem 2008; 27:1399-1407. [PMID: 18220443 DOI: 10.1897/07-197.1] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/07/2007] [Accepted: 12/20/2007] [Indexed: 05/25/2023]
Abstract
Herbicide concentrations fluctuate in rivers following crop application and can reach high levels after rain events, yet the duration of these pulses is short. In the present study, we assessed the effect of atrazine and isoproturon pulse exposure on Scenedesmus vacuolatus (Chlorophyceae; strain 211-8b, Kessler) as well as the recovery in the postexposure period. We further explored whether the time-dependent toxicity is similar for herbicides inhibiting the photosystem II (PSII). The growth rate was assessed for different exposure durations, and in addition the inhibition of the effective quantum yield of PSII was measured to monitor the response at the target site. Atrazine and isoproturon did not have similar time-dependent effects on growth rate, despite their same primary mode of action on PSII. Atrazine was less toxic than isoproturon after 10 h of exposure, but the toxicity of both herbicides was similar after 48 h of exposure. However, both compounds inhibited the PSII effective quantum yield within 1 h following exposure. Similarly, the effective quantum yield recovered completely within 4 h after removal of the toxicants, leading to rapid recovery of algal growth. The rapid onset of effects of isoproturon on the growth of the alga during exposure suggests that a single pulse to this herbicide is likely to induce greater effects than an atrazine pulse at the same concentration, even if these effects are reversible. The information gained in the present study should support the effect assessment of sequential exposures as well as the risk evaluation of fluctuating herbicidal exposure.
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Affiliation(s)
- Nathalie Vallotton
- Eawag, Swiss Federal Institute of Aquatic Science and Technology, Duebendorf, Switzerland.
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48
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Abstract
Prochlorococcus and Synechococcus picocyanobacteria are dominant contributors to marine primary production over large areas of the ocean. Phytoplankton cells are entrained in the water column and are thus often exposed to rapid changes in irradiance within the upper mixed layer of the ocean. An upward fluctuation in irradiance can result in photosystem II photoinactivation exceeding counteracting repair rates through protein turnover, thereby leading to net photoinhibition of primary productivity, and potentially cell death. Here we show that the effective cross-section for photosystem II photoinactivation is conserved across the picocyanobacteria, but that their photosystem II repair capacity and protein-specific photosystem II light capture are negatively correlated and vary widely across the strains. The differences in repair rate correspond to the light and nutrient conditions that characterize the site of origin of the Prochlorococcus and Synechococcus isolates, and determine the upward fluctuation in irradiance they can tolerate, indicating that photoinhibition due to transient high-light exposure influences their distribution in the ocean.
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Affiliation(s)
- Christophe Six
- Mount Allison University, Sackville, New Brunswick, Canada
| | - Zoe V. Finkel
- Mount Allison University, Sackville, New Brunswick, Canada
| | | | - Douglas A. Campbell
- Mount Allison University, Sackville, New Brunswick, Canada
- * To whom correspondence should be addressed. E-mail:
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Veiga TAM, González-Vázquez R, Neto JO, Silva MFGF, King-Díaz B, Lotina-Hennsen B. Siderin from Toona ciliata (Meliaceae) as photosystem II inhibitor on spinach thylakoids. Arch Biochem Biophys 2007; 465:38-43. [PMID: 17568558 DOI: 10.1016/j.abb.2007.05.002] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2007] [Revised: 05/03/2007] [Accepted: 05/06/2007] [Indexed: 11/24/2022]
Abstract
Four natural products were isolated from plants of the Rutaceae and Meliaceae families and their effect on photosynthesis was tested. Siderin (1) inhibited both ATP synthesis and electron flow (basal, phosphorylating, and uncoupled) from water to methylviologen (MV); therefore, it acts as Hill reaction inhibitor in freshly lysed spinach thylakoids. Natural products 2-4 were inactive. Secondary metabolite 1 did not inhibit PSI electron transport. It inhibits partial reactions of PSII electron flow from water to 2,6-dichlorophenol indophenol (DCPIP), from water to sodium silicomolybdate, and partially inhibits electron flow from diphenylcarbazid (DPC) to DCPIP. These results established that the site of inhibition of 1 was at the donor and acceptor sides of PSII, between P(680) and Q(A). Chlorophyll a fluorescence measurements confirmed the behavior of the Toona ciliate coumarin 1 as P(680) to Q(A) inhibitor by the creation of silent centers. May be this is the mechanisms of action of 1 and is the way in which it develops a phytotoxic activity against photosynthesis.
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Affiliation(s)
- Thiago A M Veiga
- Departamento de Química, Universidade Federal de São Carlos (UFSCar), 13565-905, São Carlos, S.P., Brazil
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50
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Beauchemin R, Gauthier A, Harnois J, Boisvert S, Govindachary S, Carpentier R. Spermine and spermidine inhibition of photosystem II: Disassembly of the oxygen evolving complex and consequent perturbation in electron donation from TyrZ to P680+ and the quinone acceptors QA− to QB. Biochimica et Biophysica Acta (BBA) - Bioenergetics 2007; 1767:905-12. [PMID: 17511958 DOI: 10.1016/j.bbabio.2007.04.001] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/03/2006] [Revised: 03/30/2007] [Accepted: 04/05/2007] [Indexed: 11/17/2022]
Abstract
Polyamines are implicated in plant growth and stress response. However, the polyamines spermine and spermidine were shown to elicit strong inhibitory effects in photosystem II (PSII) submembrane fractions. We have studied the mechanism of this inhibitory action in detail. The inhibition of electron transport in PSII submembrane fractions treated with millimolar concentrations of spermine or spermidine led to the decline of plastoquinone reduction, which was reversed by the artificial electron donor diphenylcarbazide. The above inhibition was due to the loss of the extrinsic polypeptides associated with the oxygen evolving complex. Thermoluminescence measurements revealed that charge recombination between the quinone acceptors of PSII, QA and QB, and the S2 state of the Mn-cluster was abolished. Also, the dark decay of chlorophyll fluorescence after a single turn-over white flash was greatly retarded indicating a slower rate of QA- reoxidation.
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Affiliation(s)
- Rémy Beauchemin
- Groupe de recherche en Biologie Végétale, Université du Québec à Trois-Rivières, CP 500, Trois-Rivières (Québec), Canada G9A 5H7
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