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Cao T, Bai Y, Buschbeck P, Tan Q, Cantrell MB, Chen Y, Jiang Y, Liu RZ, Ries NK, Shi X, Sun Y, Ware MA, Yang F, Zhang H, Han J, Zhang L, Huang J, Lohr M, Peers G, Li X. An unexpected hydratase synthesizes the green light-absorbing pigment fucoxanthin. THE PLANT CELL 2023; 35:3053-3072. [PMID: 37100425 PMCID: PMC10396388 DOI: 10.1093/plcell/koad116] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/28/2022] [Revised: 04/05/2023] [Accepted: 04/06/2023] [Indexed: 06/19/2023]
Abstract
The ketocarotenoid fucoxanthin and its derivatives can absorb blue-green light enriched in marine environments. Fucoxanthin is widely adopted by phytoplankton species as a main light-harvesting pigment, in contrast to land plants that primarily employ chlorophylls. Despite its supreme abundance in the oceans, the last steps of fucoxanthin biosynthesis have remained elusive. Here, we identified the carotenoid isomerase-like protein CRTISO5 as the diatom fucoxanthin synthase that is related to the carotenoid cis-trans isomerase CRTISO from land plants but harbors unexpected enzymatic activity. A crtiso5 knockout mutant in the model diatom Phaeodactylum tricornutum completely lacked fucoxanthin and accumulated the acetylenic carotenoid phaneroxanthin. Recombinant CRTISO5 converted phaneroxanthin into fucoxanthin in vitro by hydrating its carbon-carbon triple bond, instead of functioning as an isomerase. Molecular docking and mutational analyses revealed residues essential for this activity. Furthermore, a photophysiological characterization of the crtiso5 mutant revealed a major structural and functional role of fucoxanthin in photosynthetic pigment-protein complexes of diatoms. As CRTISO5 hydrates an internal alkyne physiologically, the enzyme has unique potential for biocatalytic applications. The discovery of CRTISO5 illustrates how neofunctionalization leads to major diversification events in evolution of photosynthetic mechanisms and the prominent brown coloration of most marine photosynthetic eukaryotes.
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Affiliation(s)
- Tianjun Cao
- Key Laboratory of Growth Regulation and Translational Research of Zhejiang Province, School of Life Sciences, Westlake University, Hangzhou 310024, China
- Institute of Biology, Westlake Institute for Advanced Study, Hangzhou 310024, China
| | - Yu Bai
- Department of Biology, Colorado State University, Fort Collins, CO 80523, USA
| | - Paul Buschbeck
- Institut für Molekulare Physiologie, Johannes Gutenberg-University, 55099 Mainz, Germany
| | - Qiaozhu Tan
- Key Laboratory of Structural Biology of Zhejiang Province, School of Life Sciences, Westlake University, Hangzhou 310024, China
| | - Michael B Cantrell
- Department of Biology, Colorado State University, Fort Collins, CO 80523, USA
| | - Yinjuan Chen
- Key Laboratory of Precise Synthesis of Functional Molecules of Zhejiang Province, School of Science, Instrumentation and Service Center for Molecular Sciences, Westlake University, Hangzhou 310024, China
| | - Yanyou Jiang
- Key Laboratory of Growth Regulation and Translational Research of Zhejiang Province, School of Life Sciences, Westlake University, Hangzhou 310024, China
| | - Run-Zhou Liu
- Key Laboratory of Precise Synthesis of Functional Molecules of Zhejiang Province, School of Science, Westlake University, Hangzhou 310024, China
| | - Nana K Ries
- Institut für Molekulare Physiologie, Johannes Gutenberg-University, 55099 Mainz, Germany
| | - Xiaohuo Shi
- Key Laboratory of Precise Synthesis of Functional Molecules of Zhejiang Province, School of Science, Instrumentation and Service Center for Molecular Sciences, Westlake University, Hangzhou 310024, China
| | - Yan Sun
- College of Food and Pharmaceutical Sciences, Ningbo University, Ningbo 315211, China
| | - Maxwell A Ware
- Department of Biology, Colorado State University, Fort Collins, CO 80523, USA
| | - Fenghua Yang
- Key Laboratory of Structural Biology of Zhejiang Province, School of Life Sciences, Westlake University, Hangzhou 310024, China
| | - Huan Zhang
- Key Laboratory of Growth Regulation and Translational Research of Zhejiang Province, School of Life Sciences, Westlake University, Hangzhou 310024, China
- Institute of Biology, Westlake Institute for Advanced Study, Hangzhou 310024, China
| | - Jichang Han
- College of Food and Pharmaceutical Sciences, Ningbo University, Ningbo 315211, China
| | - Lihan Zhang
- Key Laboratory of Precise Synthesis of Functional Molecules of Zhejiang Province, School of Science, Westlake University, Hangzhou 310024, China
- Institute of Natural Sciences, Westlake Institute for Advanced Study, Hangzhou 310024, China
| | - Jing Huang
- Institute of Biology, Westlake Institute for Advanced Study, Hangzhou 310024, China
- Key Laboratory of Structural Biology of Zhejiang Province, School of Life Sciences, Westlake University, Hangzhou 310024, China
- Westlake Laboratory of Life Sciences and Biomedicine, Hangzhou 310024, China
| | - Martin Lohr
- Institut für Molekulare Physiologie, Johannes Gutenberg-University, 55099 Mainz, Germany
| | - Graham Peers
- Department of Biology, Colorado State University, Fort Collins, CO 80523, USA
| | - Xiaobo Li
- Key Laboratory of Growth Regulation and Translational Research of Zhejiang Province, School of Life Sciences, Westlake University, Hangzhou 310024, China
- Institute of Biology, Westlake Institute for Advanced Study, Hangzhou 310024, China
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2
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Cantrell M, Cano M, Sebesta J, Paddock T, Xiong W, Chou KJ, Yu J. Manipulation of glycogen and sucrose synthesis increases photosynthetic productivity in cyanobacteria. Front Microbiol 2023; 14:1124274. [PMID: 37275163 PMCID: PMC10233058 DOI: 10.3389/fmicb.2023.1124274] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2022] [Accepted: 05/05/2023] [Indexed: 06/07/2023] Open
Abstract
Photosynthetic productivity is limited by low energy conversion efficiency in naturally evolved photosynthetic organisms, via multiple mechanisms that are not fully understood. Here we show evidence that extends recent findings that cyanobacteria use "futile" cycles in the synthesis and degradation of carbon compounds to dissipate ATP. Reduction of the glycogen cycle or the sucrose cycle in the model cyanobacterium Synechocystis 6803 led to redirection of cellular energy toward faster growth under simulated outdoor light conditions in photobioreactors that was accompanied by higher energy charge [concentration ratio of ATP/(ATP + ADP)]. Such manipulation of energy metabolism may have potential in engineering microalgal chassis cells to increase productivity of biomass or target metabolites.
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3
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Ritchie RJ, Sma-Air S, Kongkawn C, Sawattawee J. Photosynthetic electron transport in pitcher plants (Nepenthes mirabilis). PHOTOSYNTHESIS RESEARCH 2023; 155:147-158. [PMID: 36414834 DOI: 10.1007/s11120-022-00987-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/18/2022] [Accepted: 11/14/2022] [Indexed: 06/16/2023]
Abstract
Pitcher plants (Nepenthes sp.) are insectivorous angiosperm plants with modified leaves known as pitchers best known as acting as traps for insects. Pitcher plants are typically found under boggy conditions under both forest cover and open areas with very poor nutrient status, particularly N-status. The pitchers have low photosynthetic activity. The Chl a content of the pitcher tissue of both Nepenthes mirabilis (green and red) varieties was very low. Chl b/a ratios of the green variety phyllodes (lamina) and pitchers were ≈ 0.24 to 0.29. In the red variety, the mature phyllodes had a Chl b/a ratio ≈ 0.28 but both the pitchers and the young phyllodes had Chl b/a ratios of nearly 0.5. Photosynthetic electron transport (ETR) was measured using PAM technology. Phyllodes of both varieties showed photoinhibition at supra-optimal irradiances [Nepenthes mirabilis (green variety), Eopt ≈ 200-250 µmol photon m-2 s-1; red variety, Eopt ≈ 100-150 µmol photon m-2 s-1]. Pitchers had low optimum irradiances (Eopt ≈ 40-90 µmol photon m-2 s-1). Maximum ETR (ETRmax) of phyllodes of both varieties was low (ETRmax ≈ 50 µmol e- g-1 Chl a s-1); ETRmax was higher for pitchers on a Chl a basis (ETRmax ≈ 80-100 µmol e- g-1 Chl a s-1); a consequence of their low Chl a content on a surface area basis. ETRmax of cut disks of phyllodes did not respond strongly to incubation in NH4+, glutamate or aspartate as N-sources but did respond positively to added urea.
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Affiliation(s)
- Raymond J Ritchie
- Faculty of Technology and Environment, Prince of Songkla University in Phuket, Kathu, Phuket, 83120, Thailand.
- Andaman Environment and Natural Disaster Research Centre, Prince of Songkla University in Phuket, Kathu, Phuket, 83120, Thailand.
| | - Suhailar Sma-Air
- Faculty of Technology and Environment, Prince of Songkla University in Phuket, Kathu, Phuket, 83120, Thailand
- Andaman Environment and Natural Disaster Research Centre, Prince of Songkla University in Phuket, Kathu, Phuket, 83120, Thailand
| | - Chaturong Kongkawn
- Faculty of Technology and Environment, Prince of Songkla University in Phuket, Kathu, Phuket, 83120, Thailand
| | - Jinda Sawattawee
- Faculty of Technology and Environment, Prince of Songkla University in Phuket, Kathu, Phuket, 83120, Thailand
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Zepernick BN, Niknejad DJ, Stark GF, Truchon AR, Martin RM, Rossignol KL, Paerl HW, Wilhelm SW. Morphological, physiological, and transcriptional responses of the freshwater diatom Fragilaria crotonensis to elevated pH conditions. Front Microbiol 2022; 13:1044464. [PMID: 36504786 PMCID: PMC9732472 DOI: 10.3389/fmicb.2022.1044464] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2022] [Accepted: 11/07/2022] [Indexed: 11/27/2022] Open
Abstract
Harmful algal blooms (HABs) caused by the toxin-producing cyanobacteria Microcystis spp., can increase water column pH. While the effect(s) of these basified conditions on the bloom formers are a high research priority, how these pH shifts affect other biota remains understudied. Recently, it was shown these high pH levels decrease growth and Si deposition rates in the freshwater diatom Fragilaria crotonensis and natural Lake Erie (Canada-US) diatom populations. However, the physiological mechanisms and transcriptional responses of diatoms associated with these observations remain to be documented. Here, we examined F. crotonensis with a set of morphological, physiological, and transcriptomic tools to identify cellular responses to high pH. We suggest 2 potential mechanisms that may contribute to morphological and physiological pH effects observed in F. crotonensis. Moreover, we identified a significant upregulation of mobile genetic elements in the F. crotonensis genome which appear to be an extreme transcriptional response to this abiotic stress to enhance cellular evolution rates-a process we have termed "genomic roulette." We discuss the ecological and biogeochemical effects high pH conditions impose on fresh waters and suggest a means by which freshwater diatoms such as F. crotonensis may evade high pH stress to survive in a "basified" future.
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Affiliation(s)
| | - David J. Niknejad
- Department of Microbiology, University of Tennessee, Knoxville, TN, United States
| | - Gwendolyn F. Stark
- Department of Microbiology, University of Tennessee, Knoxville, TN, United States
| | - Alexander R. Truchon
- Department of Microbiology, University of Tennessee, Knoxville, TN, United States
| | - Robbie M. Martin
- Department of Microbiology, University of Tennessee, Knoxville, TN, United States
| | - Karen L. Rossignol
- Institute of Marine Sciences, University of North Carolina at Chapel Hill, Morehead City, NC, United States
| | - Hans W. Paerl
- Institute of Marine Sciences, University of North Carolina at Chapel Hill, Morehead City, NC, United States
| | - Steven W. Wilhelm
- Department of Microbiology, University of Tennessee, Knoxville, TN, United States
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Antosiak A, Šulčius S, Malec P, Tokodi N, Łobodzińska A, Dziga D. Cyanophage infections reduce photosynthetic activity and expression of CO 2 fixation genes in the freshwater bloom-forming cyanobacterium Aphanizomenon flos-aquae. HARMFUL ALGAE 2022; 116:102215. [PMID: 35710200 DOI: 10.1016/j.hal.2022.102215] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/23/2021] [Revised: 02/20/2022] [Accepted: 02/25/2022] [Indexed: 06/15/2023]
Abstract
Cyanobacteria play a significant role in ecosystem functioning as photosynthetic and CO2 fixing microorganisms. Whether and to what extent cyanophages alter these carbon and energy cycles in their cyanobacterial hosts is still poorly understood. In this study, we investigated changes in photosynthetic activity (PSII), expression of genes associated with the light phase of photosynthesis (psbA, petA, ndhK) and carbon metabolism (rbcL, zwf) as well as intracellular ATP and NADHP concentrations in freshwater bloom-forming filamentous cyanobacterium Aphanizomenon flos-aquae infected by cyanophage vB_AphaS-CL131. We found that PSII activity and expression level of rbcL genes, indicating potential for CO2 fixation, had decreased in response to cyanophage adsorption and DNA injection. During the period of viral DNA replication and assembly, PSII performance and gene expression remained at this decreased level and did not change significantly, indicating lack of transcriptional shutdown by the cyanophage. Combined, these observations suggest that although there is little to no interference between cyanophage DNA replication, host transcription and cellular metabolism, A. flos-aquae underwent a physiological state-shift toward lower efficiency of carbon and energy cycling. This further suggest potential cascading effect for co-occurring non-infected members of the microbial community.
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Affiliation(s)
- Adam Antosiak
- Laboratory of Metabolomics, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Gronostajowa 7, 30387 Krakow, Poland.
| | - Sigitas Šulčius
- Laboratory of Algology and Microbial Ecology, Nature Research Centre, Akademijos str. 2, 08412 Vilnius, Lithuania.
| | - Przemysław Malec
- Department of Plant Physiology and Biochemistry, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Gronostajowa 7, 30387 Krakow, Poland.
| | - Nada Tokodi
- Laboratory of Metabolomics, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Gronostajowa 7, 30387 Krakow, Poland; Department of Biology and Ecology, University of Novi Sad, Faculty of Sciences, Trg Dositeja Obradovića 3, 21000 Novi Sad, Serbia.
| | - Antonia Łobodzińska
- Laboratory of Metabolomics, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Gronostajowa 7, 30387 Krakow, Poland.
| | - Dariusz Dziga
- Laboratory of Metabolomics, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Gronostajowa 7, 30387 Krakow, Poland.
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6
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Chlorophyll Fluorescence Imaging as a Tool for Evaluating Disease Resistance of Common Bean Lines in the Western Amazon Region of Colombia. PLANTS 2022; 11:plants11101371. [PMID: 35631796 PMCID: PMC9143997 DOI: 10.3390/plants11101371] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/06/2022] [Revised: 05/19/2022] [Accepted: 05/20/2022] [Indexed: 11/24/2022]
Abstract
The evaluation of disease resistance is considered an important aspect of phenotyping for crop improvement. Identification of advanced lines of the common bean with disease resistance contributes to improved grain yields. This study aimed to determine the response of the photosynthetic apparatus to natural pathogen infection by using chlorophyll (Chla) fluorescence parameters and their relationship to the agronomic performance of 59 common bean lines and comparing the photosynthetic responses of naturally infected vs. healthy leaves. The study was conducted over two seasons under acid soil and high temperature conditions in the western Amazon region of Colombia. A disease susceptibility index (DSI) was developed and validated using chlorophyll a (Chla) fluorescence as a tool to identify Mesoamerican and Andean lines of common bean (Phaseolus vulgaris L.) that are resistant to pathogens. A negative effect on the functional status of the photosynthetic apparatus was found with the presence of pathogen infection, a situation that allowed the identification of four typologies based on the DSI values ((i) moderately resistant; (ii) moderately susceptible; (iii) susceptible; and (iv) highly susceptible). Moderately resistant lines, five of them from the Mesoamerican gene pool (ALB 350, SMC 200, BFS 10, SER 16, SMN 27) and one from the Andean gene pool (DAB 295), allocated a higher proportion of energy to photochemical processes, which increased the rate of electron transfer resulting in a lower sensitivity to disease stress. This photosynthetic response was associated with lower values of DSI, which translated into an increase in the accumulation of dry matter accumulation in different plant organs (leaves, stem, pods and roots). Thus, DSI values based on chlorophyll fluorescence response to pathogen infection could serve as a phenotyping tool for evaluating advanced common bean lines. Six common bean lines (ALB 350, BFS 10, DAB 295, SER 16, SMC 200 and SMN 27) were identified as less sensitive to disease stress under field conditions in the western Amazon region of Colombia, and these could serve as useful parents for improving the common bean for multiple stress resistance.
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7
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Depth optimization of inclined thin layer photobioreactor for efficient microalgae cultivation in high turbidity digestate. ALGAL RES 2021. [DOI: 10.1016/j.algal.2021.102509] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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8
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Wang L, Liu J, Filipiak M, Mungunkhuyag K, Jedynak P, Burczyk J, Fu P, Malec P. Fast and efficient cadmium biosorption by Chlorella vulgaris K-01 strain: The role of cell walls in metal sequestration. ALGAL RES 2021. [DOI: 10.1016/j.algal.2021.102497] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
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9
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Chuka-ogwude D, Nafisi M, Vadiveloo A, Taher H, Bahri PA, Moheimani NR. Effect of medium recycling, culture depth, and mixing duration on D. salina growth. ALGAL RES 2021. [DOI: 10.1016/j.algal.2021.102495] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
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10
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Cheregi O, Engelbrektsson J, Andersson MX, Strömberg N, Ekendahl S, Godhe A, Spetea C. Marine microalgae for outdoor biomass production-A laboratory study simulating seasonal light and temperature for the west coast of Sweden. PHYSIOLOGIA PLANTARUM 2021; 173:543-554. [PMID: 33826748 DOI: 10.1111/ppl.13412] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/13/2020] [Revised: 03/22/2021] [Accepted: 03/26/2021] [Indexed: 06/12/2023]
Abstract
At Nordic latitudes, year-round outdoor cultivation of microalgae is debatable due to seasonal variations in productivity. Shall the same species/strains be used throughout the year, or shall seasonal-adapted ones be used? To elucidate this, a laboratory study was performed where two out of 167 marine microalgal strains were selected for intended cultivation at the west coast of Sweden. The two local strains belong to Nannochloropsis granulata (Ng) and Skeletonema marinoi (Sm142). They were cultivated in photobioreactors and compared in conditions simulating variations in light and temperature of a year divided into three growth seasons (spring, summer and winter). The strains grew similarly well in summer (and also in spring), but Ng produced more biomass (0.225 vs. 0.066 g DW L-1 day-1 ) which was more energy rich (25.0 vs. 16.6 MJ kg-1 DW). In winter, Sm142 grew faster and produced more biomass (0.017 vs. 0.007 g DW L-1 day-1 ), having similar energy to the other seasons. The higher energy of the Ng biomass is attributed to a higher lipid content (40 vs. 16% in summer). The biomass of both strains was richest in proteins (65%) in spring. In all seasons, Sm142 was more effective in removing phosphorus from the cultivation medium (6.58 vs. 4.14 mg L-1 day-1 in summer), whereas Ng was more effective in removing nitrogen only in summer (55.0 vs. 30.8 mg L-1 day-1 ). Our results suggest that, depending on the purpose, either the same or different local species can be cultivated, and are relevant when designing outdoor studies.
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Affiliation(s)
- Otilia Cheregi
- Department of Biological and Environmental Sciences, University of Gothenburg, Gothenburg, Sweden
| | - Johan Engelbrektsson
- Department of Chemistry, Biomaterials and Textiles, RISE Research Institutes of Sweden AB, Gothenburg, Sweden
| | - Mats X Andersson
- Department of Biological and Environmental Sciences, University of Gothenburg, Gothenburg, Sweden
| | - Niklas Strömberg
- Department of Chemistry, Biomaterials and Textiles, RISE Research Institutes of Sweden AB, Gothenburg, Sweden
| | - Susanne Ekendahl
- Department of Chemistry, Biomaterials and Textiles, RISE Research Institutes of Sweden AB, Gothenburg, Sweden
| | - Anna Godhe
- Department of Marine Sciences, University of Gothenburg, Gothenburg, Sweden
| | - Cornelia Spetea
- Department of Biological and Environmental Sciences, University of Gothenburg, Gothenburg, Sweden
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11
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Alsiyabi A, Brown B, Immethun C, Long D, Wilkins M, Saha R. Synergistic experimental and computational approach identifies novel strategies for polyhydroxybutyrate overproduction. Metab Eng 2021; 68:1-13. [PMID: 34464732 DOI: 10.1016/j.ymben.2021.08.008] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Revised: 07/28/2021] [Accepted: 08/25/2021] [Indexed: 11/28/2022]
Abstract
Polyhydroxybutyrate (PHB) is a sustainable bioplastic produced by bacteria that is a potential replacement for conventional plastics. This study delivers an integrated experimental and computational modeling approach to decipher metabolic factors controlling PHB production and offers engineering design strategies to boost production. In the metabolically robust Rhodopseudomonas palustris CGA009, PHB production significantly increased when grown on the carbon- and electron-rich lignin breakdown product p-coumarate (C9H8O3) compared to virtually no PHB titer from acetate (C2H3NaO2). The maximum yield did not improve further when grown on coniferyl alcohol (C10H12O3), but comparison of the PHB profiles showed that coniferyl alcohol's higher carbon content resulted in a higher rate of PHB production. Combined experimental results revealed that cytoplasmic space may be a limiting factor for maximum PHB titer. In order to obtain a systems-level understanding of factors driving PHB yield, a model-driven investigation was performed. The model yielded several engineering design strategies including utilizing reduced, high molecular weight substrates that bypass the thiolase reaction (phaA). Based on these strategies, utilization of butyrate was predicted and subsequently validated to produce PHB. Model analysis also explained why nitrogen starvation was not essential for PHB production and revealed that renewable and abundant lignin aromatics are ideal candidates for PHB production. Most importantly, the generality of the derived design rules allows them to be applied to any PHB-producing microbe with similar metabolic features.
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Affiliation(s)
- Adil Alsiyabi
- Department of Chemical and Biomolecular Engineering, University of Nebraska-Lincoln, Lincoln, NE, 68588, USA
| | - Brandi Brown
- Department of Biological Systems Engineering, University of Nebraska-Lincoln, Lincoln, NE, 68583, USA
| | - Cheryl Immethun
- Department of Chemical and Biomolecular Engineering, University of Nebraska-Lincoln, Lincoln, NE, 68588, USA
| | - Dianna Long
- Department of Biological Systems Engineering, University of Nebraska-Lincoln, Lincoln, NE, 68583, USA
| | - Mark Wilkins
- Department of Biological Systems Engineering, University of Nebraska-Lincoln, Lincoln, NE, 68583, USA; Industrial Agricultural Products Center, University of Nebraska-Lincoln, Lincoln, NE, 68583, USA; Department of Food Science and Technology, University of Nebraska-Lincoln, Lincoln, NE, 68588, USA
| | - Rajib Saha
- Department of Chemical and Biomolecular Engineering, University of Nebraska-Lincoln, Lincoln, NE, 68588, USA.
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12
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Lewis VR, Farrell AD, Umaharan P, Lennon AM. Genetic variation in high light responses of Theobroma cacao L. accessions. Heliyon 2021; 7:e07404. [PMID: 34307928 PMCID: PMC8258650 DOI: 10.1016/j.heliyon.2021.e07404] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2021] [Revised: 05/07/2021] [Accepted: 06/22/2021] [Indexed: 10/27/2022] Open
Abstract
Cacao (Theobroma cacao L.) is a shade-tolerant tree species, but in recent years it has increasingly been cultivated under full sun conditions in an orchard system where photoinhibition is likely. Here we investigate the extent of photoinhibition in 17 cacao accessions from a range of genetic groups, growing under high light conditions. The ability of the photosynthetic systems to respond to high light was assessed using chlorophyll fluorescence parameters (diurnal F v /F m and instantaneous light response curves), and differences in photosynthetic pigment content were compared using biochemical assays. Damage due to photoinhibition was assessed using electrolyte leakage, lipid peroxidation, and reactive oxygen species scavenging systems were compared using biochemical assays (for APX, CAT and SOD). There was significant variation between the 17 accessions for photosynthetic parameters, although in all cases the light saturation points were well below the midday light levels. Light acclimation of photosynthetic pigments was evident and variation in the total chlorophyll to total carotenoid ratio was significantly correlated with electrolyte leakage. Significant genetic variation was observed across the 17 accessions in the activities of CAT, APX and SOD. Across all accessions, photoprotection appeared to be restricted by the ability of leaves to generate SOD. Significant negative correlations were observed between SOD activity and both APX activity and electrolyte leakage, while significant positive correlations were observed between electrolyte leakage and both APX and CAT activity. Accessions with higher light saturation points, as well as high carotenoid and high SOD concentrations were able to tolerate the moderately high light, however, none of the accessions were clearly superior to the commonly grown Amelonado accession. The results imply that screening for SOD activity, total carotenoid content and light saturation point can aid in selection of genotypes with better tolerance to high light.
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Affiliation(s)
- Vernessa R Lewis
- Department of Life Sciences, Faculty of Science and Technology, The University of the West Indies, St. Augustine Campus, College Road, Trinidad and Tobago
| | - Aidan D Farrell
- Department of Life Sciences, Faculty of Science and Technology, The University of the West Indies, St. Augustine Campus, College Road, Trinidad and Tobago
| | - Pathmanathan Umaharan
- Cocoa Research Centre, The University of the West Indies, St. Augustine Campus, Trinidad and Tobago
| | - Adrian M Lennon
- Department of Life Sciences, Faculty of Science and Technology, The University of the West Indies, St. Augustine Campus, College Road, Trinidad and Tobago
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13
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Sma-Air S, Ritchie RJ. Spectrofluorometric Insights into the Application of PAM Fluorometry in Photosynthetic Research. Photochem Photobiol 2021; 97:991-1000. [PMID: 33704805 DOI: 10.1111/php.13413] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Revised: 02/22/2021] [Accepted: 03/08/2021] [Indexed: 11/29/2022]
Abstract
Although pulse amplitude modulation (PAM) fluorometry has revolutionized photosynthetic studies, Photosynthetic Electron Transport Rate (ETR) cannot be measured using PAM technology in some organisms. We compare in vivo absorbance information on a selection of photosynthetic organisms using an integrating sphere spectrophotometry on a variety of oxygenic and nonoxygenic photo-organisms and provide fluorescence data to help in understanding why PAM technology is unsuccessful on some organisms, particularly cyanobacteria. The study includes anoxygenic photosynthetic bacteria: Afifella marina, Rhodopseudomonas palustris and Thermochromatium which are all RC-2 type photosynthetic bacteria (Bacteriochlorophyll a or BChl a) which are known to have measureable delayed fluorescence, Yield and hence measureable ETR. The common unicellular green alga, Chlorella sp (Chl a + b) uses the same primary photosynthetic pigments as vascular plants. Comparisons are made to some other representative oxygenic unicellular organisms: Trebouxia (Chlorophyta, Chl a + b), Chaetoceros (a diatom, Chl a + c1 c2 ) and the unusual cyanobacterium Acaryochloris marina which has Chl d + a but uses Chl d as its primary photosynthetic pigment. Synechococcus R-2 (Cyanobacteria) has only Chl a. Its fluorescence is outside the range normally used for measuring photosynthesis using PAM technology: delayed fluorescence is not readily detectable.
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Affiliation(s)
- Suhailar Sma-Air
- ANED (Andaman Environment and Natural Disaster Research Centre), Faculty of Technology and Environment, Prince of Songkla University-Phuket, Phuket, Thailand
| | - Raymond J Ritchie
- ANED (Andaman Environment and Natural Disaster Research Centre), Faculty of Technology and Environment, Prince of Songkla University-Phuket, Phuket, Thailand
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Seasonal Photoacclimation and Vulnerability Patterns in the Brown Macroalga Lessonia spicata (Ochrophyta). WATER 2020. [DOI: 10.3390/w13010006] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Fluctuations in solar radiation are one of the key factors affecting productivity and survival in habitat forming coastal macroalgae, in this regard, photoacclimation has a direct impact on the vulnerability and the capacity of seaweed to withstand, for instance, radiation excess. Here, we study ecophysiological responses through photosynthetic activity measurements under time-dependent (one year) fluctuations in solar radiation in the brown macroalga L. spicata. The responses presented seasonal patterns, with an increase in photosynthetic capacity during summer, expressed in greater maximal electron transport rate (ETRmax) and diminished thermal dissipation (NPQmax). Moreover, we studied photoprotective compounds (phenolic compounds) and total antioxidant capacity, which demonstrated an increase during periods of high solar radiation. In addition, content of photosynthetic pigment (Chla, Chlc and Carotenoids) increased under greater solar irradiance. The L. spicata can accumulate as reservoir photoprotective and antioxidant substances to withstand periods of high solar irradiance. All ecophysiological and biochemical responses in L. spicata indicate high photoacclimation and low vulnerability in the species, especially during with greater levels of solar irradiance.
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A relook into plant wilting: observational evidence based on unsaturated soil-plant-photosynthesis interaction. Sci Rep 2020; 10:22064. [PMID: 33328549 PMCID: PMC7744524 DOI: 10.1038/s41598-020-78893-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2020] [Accepted: 11/20/2020] [Indexed: 11/09/2022] Open
Abstract
Permanent wilting point (PWP) is generally used to ascertain plant resistance against abiotic drought stress and designated as the soil water content (θ) corresponding to soil suction (ψ) at 1500 kPa obtained from the soil water retention curve. Determination of PWP based on only pre-assumed ψ may not represent true wilting condition for soils with contrasting water retention abilities. In addition to ψ, there is a need to explore significance of additional plant parameters (i.e., stomatal conductance and photosynthetic status) in determining PWP. This study introduces a new framework for determining PWP by integrating plant leaf response and ψ during drought. Axonopus compressus were grown in two distinct textured soils (clayey loam and silty sand), after which drought was initiated till wilting. Thereafter, ψ and θ within the root zone were measured along with corresponding leaf stomatal conductance and photosynthetic status. It was found that coarse textured silty sand causes wilting at much lower ψ (≈ 300 kPa) than clayey loam (≈ 1600 kPa). Plant response to drought was dependent on the relative porosity and mineralogy of the soil, which governs the ease at which roots can grow, assimilate soil O2, and uptake water. For clay loam, the held water within the soil matrix does not facilitate easy root water uptake by relatively coarse root morphology. Contrastingly, fine root hair formation in silty sand facilitated higher plant water uptake and doubled the plant survival time.
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Adjustments of the photosynthetic unit and compensation mechanisms of tolerance to high ammonia concentration in Chlorella sp. grown in food waste digestate. ALGAL RES 2020. [DOI: 10.1016/j.algal.2020.102106] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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17
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Metabolomics for early detection of stress in freshwater alga Poterioochromonas malhamensis exposed to silver nanoparticles. Sci Rep 2020; 10:20563. [PMID: 33239722 PMCID: PMC7689461 DOI: 10.1038/s41598-020-77521-0] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2020] [Accepted: 11/12/2020] [Indexed: 12/13/2022] Open
Abstract
Silver nanoparticles (AgNPs) are one of the most used engineered nanomaterials. Despite progress in assessing their environmental implications, knowledge gaps exist concerning the metabolic perturbations induced by AgNPs on phytoplankton, essential organisms in global biogeochemical cycles and food-web dynamics. We combine targeted metabolomics, biouptake and physiological response studies to elucidate metabolic perturbations in alga Poterioochromonas malhamensis induced by AgNPs and dissolved Ag. We show time-dependent perturbation of the metabolism of amino acids, nucleotides, fatty acids, tricarboxylic acids, photosynthesis and photorespiration by both Ag-treatments. The results suggest that dissolved Ag ions released by AgNPs are the major toxicity driver; however, AgNPs internalized in food vacuoles contributed to the perturbation of amino acid metabolism, TCA cycle and oxidative stress. The metabolic perturbations corroborate the observed physiological responses. We highlight the potential of metabolomics as a tool for understanding the molecular basis for these metabolic and physiological changes, and for early detection of stress.
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18
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A fluorescence-based approach to screen for productive chemically mutagenized strains of Desmodesmus armatus. ALGAL RES 2020. [DOI: 10.1016/j.algal.2020.102028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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19
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Perera-Castro AV, Waterman MJ, Turnbull JD, Ashcroft MB, McKinley E, Watling JR, Bramley-Alves J, Casanova-Katny A, Zuniga G, Flexas J, Robinson SA. It Is Hot in the Sun: Antarctic Mosses Have High Temperature Optima for Photosynthesis Despite Cold Climate. FRONTIERS IN PLANT SCIENCE 2020; 11:1178. [PMID: 32922412 PMCID: PMC7457050 DOI: 10.3389/fpls.2020.01178] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/20/2020] [Accepted: 07/21/2020] [Indexed: 05/05/2023]
Abstract
The terrestrial flora of Antarctica's frozen continent is restricted to sparse ice-free areas and dominated by lichens and bryophytes. These plants frequently battle sub-zero temperatures, extreme winds and reduced water availability; all influencing their ability to survive and grow. Antarctic mosses, however, can have canopy temperatures well above air temperature. At midday, canopy temperatures can exceed 15°C, depending on moss turf water content. In this study, the optimum temperature of photosynthesis was determined for six Antarctic moss species: Bryum pseudotriquetrum, Ceratodon purpureus, Chorisodontium aciphyllum, Polytrichastrum alpinum, Sanionia uncinata, and Schistidium antarctici collected from King George Island (maritime Antarctica) and/or the Windmill Islands, East Antarctica. Both chlorophyll fluorescence and gas exchange showed maximum values of electron transport rate occurred at canopy temperatures higher than 20°C. The optimum temperature for both net assimilation of CO2 and photoprotective heat dissipation of three East Antarctic species was 20-30°C and at temperatures below 10°C, mesophyll conductance did not significantly differ from 0. Maximum mitochondrial respiration rates occurred at temperatures higher than 35°C and were lower by around 80% at 5°C. Despite the extreme cold conditions that Antarctic mosses face over winter, the photosynthetic apparatus appears optimised to warm temperatures. Our estimation of the total carbon balance suggests that survival in this cold environment may rely on a capacity to maximize photosynthesis for brief periods during summer and minimize respiratory carbon losses in cold conditions.
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Affiliation(s)
- Alicia V. Perera-Castro
- Department of Biology, Universitat de les Illes Balears, INAGEA, Palma de Mallorca, Spain
- Centre for Sustainable Ecosystem Solutions, School of Earth, Atmosphere and Life Sciences, University of Wollongong, Wollongong, NSW, Australia
| | - Melinda J. Waterman
- Centre for Sustainable Ecosystem Solutions, School of Earth, Atmosphere and Life Sciences, University of Wollongong, Wollongong, NSW, Australia
| | - Johanna D. Turnbull
- Centre for Sustainable Ecosystem Solutions, School of Earth, Atmosphere and Life Sciences, University of Wollongong, Wollongong, NSW, Australia
| | - Michael B. Ashcroft
- Centre for Sustainable Ecosystem Solutions, School of Earth, Atmosphere and Life Sciences, University of Wollongong, Wollongong, NSW, Australia
| | - Ella McKinley
- School of Biological Sciences, The University of Adelaide, Adelaide, SA, Australia
| | - Jennifer R. Watling
- School of Biological Sciences, The University of Adelaide, Adelaide, SA, Australia
- Manchester Metropolitan University, Manchester, United Kingdom
| | - Jessica Bramley-Alves
- Centre for Sustainable Ecosystem Solutions, School of Earth, Atmosphere and Life Sciences, University of Wollongong, Wollongong, NSW, Australia
| | - Angelica Casanova-Katny
- Laboratorio de Ecofisiología Vegetal y Cambio Climático y Núcleo de Estudios Ambientales (NEA), Facultad de Recursos Naturales, Universidad Católica de Temuco, Temuco, Chile
| | - Gustavo Zuniga
- Facultad de Química y Biología, Universidad de Santiago de Chile, Santiago, Chile
| | - Jaume Flexas
- Department of Biology, Universitat de les Illes Balears, INAGEA, Palma de Mallorca, Spain
| | - Sharon A. Robinson
- Centre for Sustainable Ecosystem Solutions, School of Earth, Atmosphere and Life Sciences, University of Wollongong, Wollongong, NSW, Australia
- Global Challenges Program, University of Wollongong, Wollongong, NSW, Australia
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Sma-Air S, Ritchie RJ. Photosynthesis in a Vanda sp orchid with Photosynthetic Roots. JOURNAL OF PLANT PHYSIOLOGY 2020; 251:153187. [PMID: 32505060 DOI: 10.1016/j.jplph.2020.153187] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/25/2020] [Revised: 04/30/2020] [Accepted: 05/02/2020] [Indexed: 06/11/2023]
Abstract
PAM fluorometry showed that the orchid Vanda sp (Gaud ex Pfitzers, Vandeae) had photosynthetic electron transport yields in leaves reaching ≈ 0.617 ± 0.262 at midday. Yield decayed exponentially as irradiance increased (Y½ = 128 ± 12.4 μmol photon m-2 s-1). Optimum irradiance (Eopt) for ETR (Photosynthetic Electron Transport Rate) was ≈ 369 ± 23.3 μmol photon m-2 s-1; the maximum photosynthetic ETR (ETRmax) (on a Chl a basis) ≈ 97.6 ± 3.76 μmol e-g-1 Chl a s-1. Rapid light curves exhibited classic photoinhibition at high irradiances: Vanda sp is a shade plant. Photosynthetic kinetics was strongly diurnal with minimal Eopt and ETRmax in the early morning, reaching a maximum at midday and decreasing in the afternoon. The aerial roots were normally photosynthetically dormant but rapidly activated when wet (homiochlorophyllous) then becoming dormant again after drying. Wet roots deliberately incubated under moist conditions had photosynthetic light curves comparable to leaves (Ymax ≈0.332, Y½ = ≈ 78.3 ± 27.8 μmol photons m-2 s-1, Eopt ≈ 278 μmol photons m-2 s-1 and ETRmax ≈ 317 ± 86.9 μmol e-g-1 Chl a s-1): wetting for only 15 min activated photosynthesis. Leaves showed a small degree of diurnal cycling of titratable acid but acid was accumulated in the early morning, not at night, this is a type of CAM-cycling. Titratable acid was low at sunrise (≈ 54.1 μmol H+g-1 FW), but increased until about 9 a.m. (≈ 137 μmol H+g-1 FW) and then gradually decreased over the course of the day.
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Affiliation(s)
- Suhailar Sma-Air
- Tropical Plant Biology Unit, Faculty of Technology and Environment, Prince of Songkla University - Phuket, Kathu, Phuket 83120, Thailand.
| | - Raymond J Ritchie
- Tropical Plant Biology Unit, Faculty of Technology and Environment, Prince of Songkla University - Phuket, Kathu, Phuket 83120, Thailand.
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21
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Webb JP, van Keulen M, Wong SKS, Hamley E, Nwoba E, Moheimani NR. Light spectral effect on a consortium of filamentous green algae grown on anaerobic digestate piggery effluent (ADPE). ALGAL RES 2020. [DOI: 10.1016/j.algal.2019.101723] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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22
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Hak K, Ritchie RJ, Dummee V. Bioaccumulation and physiological responses of the Coontail, Ceratophyllum demersum exposed to copper, zinc and in combination. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2020; 189:110049. [PMID: 31812820 DOI: 10.1016/j.ecoenv.2019.110049] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/07/2019] [Revised: 11/29/2019] [Accepted: 12/02/2019] [Indexed: 06/10/2023]
Abstract
Ceratophyllum demersum is a submerged aquatic angiosperm which is fast growing in contaminated water. This plant has no roots and so takes up nutrients from the water column without the complicating factor of differential shoot/root uptake of nutrients. This study aimed to compare the bioaccumulative capacities of Cu, Zn and their combination by C. demersum and physiological responses (growth, chlorophyll content, and photosynthetic rate) of C. demersum to Cu and Zn. Additionally, pulse amplitude modulation (PAM) technology and integrating sphere spectrometer were applied to detect copper and zinc toxicity effects on the light reactions of photosynthesis C. demersum is an aquatic plant that could be a good accumulator of Cu and Zn in actual solution in the water column. Additionally, RGR (relative growth rate) and chlorophyll content of C. demersum show that toxic effects of Cu or Zn increased over time. Cu and Zn effects manifested themselves more slowly than expected: at least 5 to 10 d were needed for noticeable effects both macroscopically (physical appearance), biochemical (chlorophyll content) and from measurements of photosynthesis using Pulse Amplitude Modulation (PAM) fluorometry. Moreover, the combination of Cu and Zn caused more toxic effect than either Cu or Zn separately. Whole plant scans using an integrating sphere spectrophotometer showed that Cu, Zn and Zn + Cu toxicity effects could be identified from spectral scans but were not specific enough for Cu, Zn and Zn + Cu toxicity to be distinguished from one another.
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Affiliation(s)
- Kosal Hak
- Interdisciplinary Graduate School of Earth System Science and Andaman Natural Disaster Management, Prince of Songkla University, Phuket Campus, Kathu, Phuket, 83120, Thailand.
| | - Raymond J Ritchie
- Faculty of Technology and Environment, Prince of Songkla University, Phuket Campus, Kathu, Phuket, 83120, Thailand.
| | - Vipawee Dummee
- Faculty of Technology and Environment, Prince of Songkla University, Phuket Campus, Kathu, Phuket, 83120, Thailand.
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Rahman A, Kumar S, Bafana A, Dahoumane SA, Jeffryes C. Individual and Combined Effects of Extracellular Polymeric Substances and Whole Cell Components of Chlamydomonas reinhardtii on Silver Nanoparticle Synthesis and Stability. Molecules 2019; 24:molecules24050956. [PMID: 30857177 PMCID: PMC6429613 DOI: 10.3390/molecules24050956] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2019] [Revised: 02/28/2019] [Accepted: 03/04/2019] [Indexed: 12/20/2022] Open
Abstract
The fresh water microalga Chlamydomonas reinhardtii bioreduced Ag⁺ to silver nanoparticles (AgNPs) via three biosynthetic routes in a process that could be a more sustainable alternative to conventionally produced AgNPs. The AgNPs were synthesized in either the presence of whole cell cultures, an exopolysaccharide (EPS)-containing cell culture supernatant, or living cells that had been separated from the EPS-containing supernatant and then washed before being suspended again in fresh media. While AgNPs were produced by all three methods, the washed cultures had no supernatant-derived EPS and produced only unstable AgNPs, thus the supernatant-EPS was shown to be necessary to cap and stabilize the biogenic AgNPs. TEM images showed stable AgNPs were mostly spherical and showed a bimodal size distribution about the size ranges of 3.0 ± 1.3 nm and 19.2 ± 5.0 nm for whole cultures and 3.5 ± 0.6 nm and 17.4 ± 2.6 nm for EPS only. Moreover, selected area electron diffraction pattern of these AgNPs confirmed their polycrystalline nature. FTIR of the as-produced AgNPs identified polysaccharides, polyphenols and proteins were responsible for the observed differences in the AgNP stability, size and shape. Additionally, Raman spectroscopy indicated carboxylate and amine groups were bound to the AgNP surface.
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Affiliation(s)
- Ashiqur Rahman
- Nanobiomaterials and Bioprocessing Laboratory (NABLAB), Dan F. Smith Department of Chemical Engineering, Lamar University, Beaumont, TX 77710, USA.
| | - Shishir Kumar
- Nanobiomaterials and Bioprocessing Laboratory (NABLAB), Dan F. Smith Department of Chemical Engineering, Lamar University, Beaumont, TX 77710, USA.
| | - Adarsh Bafana
- Nanobiomaterials and Bioprocessing Laboratory (NABLAB), Dan F. Smith Department of Chemical Engineering, Lamar University, Beaumont, TX 77710, USA.
| | - Si Amar Dahoumane
- School of Biological Sciences and Engineering, Yachay Tech University, Hacienda San José s/n, San Miguel de Urcuquí 100119, Ecuador.
| | - Clayton Jeffryes
- Nanobiomaterials and Bioprocessing Laboratory (NABLAB), Dan F. Smith Department of Chemical Engineering, Lamar University, Beaumont, TX 77710, USA.
- Center for Advances in Water & Air Quality, Lamar University, 211 Redbird Ln, Box 10888, Beaumont, TX 77710-0088, USA.
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24
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Modeling the impact of rotifer contamination on microalgal production in open pond, photobioreactor and thin layer cultivation systems. ALGAL RES 2019. [DOI: 10.1016/j.algal.2018.101398] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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25
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Anandraj A, White S, Mutanda T. Photosystem I fluorescence as a physiological indicator of hydrogen production in Chlamydomonas reinhardtii. BIORESOURCE TECHNOLOGY 2019; 273:313-319. [PMID: 30448683 DOI: 10.1016/j.biortech.2018.10.019] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/2018] [Revised: 10/05/2018] [Accepted: 10/06/2018] [Indexed: 06/09/2023]
Abstract
This study investigated the interrelations between hydrogen synthesis and Photosystem I electron transport rate in Chlamydomonas reinhardtii. The fluorescence of both photosystems (PS I and PS II) was monitored using a Dual Pulse Amplitude Modulated (PAM) Fluorometer. Hydrogen synthesis was induced by eliminating sulphur from the growth media (TAP-S). Multiple physiological parameters [rETR, Y (I), Y (II), NPQ, α, Fv/Fm and YI:YII] were recorded using the Dual PAM and correlated to hydrogen produced. There was a 66% increase in Photosystem I rETRmax during hydrogen production. A significant direct correlation existed between PS 1 rETRmax and hydrogen evolution values over the ten-day period (r = 0.895, p < 0.01) indicating that PS I can be considered as a driver of H2 production. Significant correlations between rETRmax of PS I and H2 evolution suggest a novel physiological indicator to monitor H2 production during the three critical phases identified in this study.
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Affiliation(s)
- Akash Anandraj
- Centre for Algal Biotechnology, Mangosuthu University of Technology, P.O. Box 12363, Jacobs, 4026 Durban, South Africa.
| | - Sarah White
- Centre for Algal Biotechnology, Mangosuthu University of Technology, P.O. Box 12363, Jacobs, 4026 Durban, South Africa
| | - Taurai Mutanda
- Centre for Algal Biotechnology, Mangosuthu University of Technology, P.O. Box 12363, Jacobs, 4026 Durban, South Africa
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Corbella M, Toa ZSD, Scholes GD, Luque FJ, Curutchet C. Determination of the protonation preferences of bilin pigments in cryptophyte antenna complexes. Phys Chem Chem Phys 2018; 20:21404-21416. [PMID: 30105318 DOI: 10.1039/c8cp02541j] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
The light-harvesting mechanisms of cryptophyte antenna complexes have attracted considerable attention due to their ability to exhibit maximal photosynthetic activity under very low-light conditions and to display several colors, as well as the observation of vibronic coherent features in their two-dimensional electronic spectra. However, detailed investigations on the interplay between the protein environment and their light-harvesting properties are hampered by the uncertainty related to the protonation state of the underlying bilin pigments. Here we study the protonation preferences of four types of bilin pigments including 15,16-dihydrobiliverdin (DBV), phycoerythrobilin (PEB), phycocyanobilin (PCB) and mesobiliverdin (MBV), which are found in phycoerythrin PE545 and phycocyanin PC577, PC612, PC630 and PC645 complexes. We apply quantum chemical calculations coupled to continuum solvation calculations to predict the intrinsic acidity of bilins in aqueous solution, and then combine molecular dynamics simulations with empirical pKa estimates to investigate the impact of the local protein environment on the acidity of the pigments. We also report measurements of the absorption spectra of the five complexes in a wide range of pH in order to validate our simulations and investigate possible changes in the light harvesting properties of the complexes in the range of physiological pH found in the lumen (pH ∼ 5-7). The results suggest a pKa > 7 for DBV and MBV pigments in the α polypeptide chains of PE545 and PC630/PC645 complexes, which are not coordinated to a negatively charged amino acid. For the other PEB, DBV and PCB pigments, which interact with a Glu or Asp side chain, higher pKa values (pKa > 8) are estimated. Overall, the results support a preferential population of the fully protonated state for bilins in cryptophyte complexes under physiological conditions regardless of the specific type of pigment and local protein environment.
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Affiliation(s)
- Marina Corbella
- Departament de Farmàcia i Tecnologia Farmacèutica i Fisicoquímica and Institut de Química Teòrica i Computacional (IQTCUB), Facultat de Farmàcia i Ciències de l'Alimentació, Universitat de Barcelona, Barcelona, Spain.
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Vadiveloo A, Moheimani N. Effect of continuous and daytime mixing on Nannochloropsis growth in raceway ponds. ALGAL RES 2018. [DOI: 10.1016/j.algal.2018.05.018] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
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28
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Huete-Ortega M, Okurowska K, Kapoore RV, Johnson MP, Gilmour DJ, Vaidyanathan S. Effect of ammonium and high light intensity on the accumulation of lipids in Nannochloropsis oceanica (CCAP 849/10) and Phaeodactylum tricornutum (CCAP 1055/1). BIOTECHNOLOGY FOR BIOFUELS 2018; 11:60. [PMID: 29541157 PMCID: PMC5844138 DOI: 10.1186/s13068-018-1061-8] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/04/2017] [Accepted: 02/23/2018] [Indexed: 06/09/2023]
Abstract
BACKGROUND Microalgae accumulate lipids when exposed to stressful conditions such as nutrient limitation that can be used to generate biofuels. Nitrogen limitation or deprivation is a strategy widely employed to elicit this response. However, this strategy is associated with a reduction in the microalgal growth, leading to overall poor lipid productivities. Here, we investigated the combined effect of a reduced source of nitrogen (ammonium) and super-saturating light intensities on the growth and induction of lipid accumulation in two model but diverse microalgal species, Phaeodactylum tricornutum and Nannochloropsis oceanica. We hypothesized that the lower energy cost of assimilating ammonium would allow the organisms to use more reductant power for lipid biosynthesis without compromising growth and that this would be further stimulated by the effect of high light (1000 µmol m-2 s-1) stress. We studied the changes in growth and physiology of both species when grown in culture media that either contained nitrate or ammonium as the nitrogen source, and an additional medium that contained ammonium with tungsten in place of molybdenum and compared this with growth in media without nitrogen. We focused our investigation on the early stages of exposure to the treatments to correspond to events relevant to induction of lipid accumulation in these two species. RESULTS At super-saturating light intensities, lipid productivity in P. tricornutum increased twofold when grown in ammonium compared to nitrogen free medium that increased further when tungsten was present in the medium in place of molybdenum. Conversely, N. oceanica growth and physiology was not compromised by the high light intensities used, and the use of ammonium had a negative effect on the lipid productivity, which was even more marked when tungsten was present. CONCLUSIONS Whilst the use of ammonium and super-saturating light intensities in P. tricornutum was revealed to be a good strategy for increasing lipid biosynthesis, no changes in the lipid productivity of N. oceanica were observed, under these conditions. Both results provide relevant direction for the better design of processes to produce biofuels in microalgae by manipulating growth conditions without the need to subject them to genetic engineering manipulation.
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Affiliation(s)
- María Huete-Ortega
- Department of Chemical and Biological Engineering, Advanced Biomanufacturing Centre, The University of Sheffield, Sir Robert Hadfield Building, Mappin Street, Sheffield, UK
- Department of Plant Sciences, University of Cambridge, Downing Street, Cambridge, UK
| | - Katarzyna Okurowska
- Department of Chemical and Biological Engineering, Advanced Biomanufacturing Centre, The University of Sheffield, Sir Robert Hadfield Building, Mappin Street, Sheffield, UK
| | - Rahul Vijay Kapoore
- Department of Chemical and Biological Engineering, Advanced Biomanufacturing Centre, The University of Sheffield, Sir Robert Hadfield Building, Mappin Street, Sheffield, UK
| | - Matthew P. Johnson
- Department of Molecular Biology and Biotechnology, The University of Sheffield, Firth Court, Western Bank, Sheffield, UK
| | - D. James Gilmour
- Department of Molecular Biology and Biotechnology, The University of Sheffield, Firth Court, Western Bank, Sheffield, UK
| | - Seetharaman Vaidyanathan
- Department of Chemical and Biological Engineering, Advanced Biomanufacturing Centre, The University of Sheffield, Sir Robert Hadfield Building, Mappin Street, Sheffield, UK
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Xie H, Yu M, Cheng X. Leaf non-structural carbohydrate allocation and C:N:P stoichiometry in response to light acclimation in seedlings of two subtropical shade-tolerant tree species. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2018; 124:146-154. [PMID: 29366973 DOI: 10.1016/j.plaphy.2018.01.013] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/11/2017] [Revised: 01/15/2018] [Accepted: 01/16/2018] [Indexed: 05/25/2023]
Abstract
UNLABELLED Light availability greatly affects plant growth and development. In shaded environments, plants must respond to reduced light intensity to ensure a regular rate of photosynthesis to maintain the dynamic balance of nutrients, such as leaf non-structural carbohydrates (NSCs), carbon (C), nitrogen (N) and phosphorus (P). To improve our understanding of the nutrient utilization strategies of understory shade-tolerant plants, we compared the variations in leaf NSCs, C, N and P in response to heterogeneous controlled light conditions between two subtropical evergreen broadleaf shade-tolerant species, Elaeocarpus sylvestris (E. sylvestris) and Illicium henryi (I. henryi). Light intensity treatments were applied at five levels (100%, 52%, 33%, 15% and 6% full sunlight) for 30 weeks to identify the effects of reduced light intensity on leaf NSC allocation patterns and leaf C:N:P stoichiometry characteristics. We found that leaf soluble sugar, starch and NSC concentrations in E. sylvestris showed decreasing trends with reduced light intensity, whereas I. henryi presented slightly increasing trends from 100% to 15% full sunlight and then significant decreases at extremely low light intensity (6% full sunlight). The soluble sugar/starch ratio of E. sylvestris decreased with decreasing light intensity, whereas that of I. henryi remained stable. Moreover, both species exhibited increasing trends in leaf N and P concentrations but limited leaf N:P and C:P ratio fluctuations with decreasing light intensity, revealing their adaptive strategies for poor light environments and their growth strategies under ideal light environments. There were highly significant correlations between leaf NSC variables and C:N:P stoichiometric variables in both species, revealing a trade-off in photosynthesis production between leaf NSC and carbon allocation. Thus, shade-tolerant plants readjusted their allocation of leaf NSCs, C, N and P in response to light acclimation. Redundancy analysis showed that leaf morphological features of both E. sylvestris and I. henryi affected their corresponding leaf nutrient traits. These results improve our understanding of the dynamic balance between leaf NSCs and leaf C, N and P components in the nutritional metabolism of shade-tolerant plants. KEY MESSAGE Two species of understory shade-tolerant plants responded differently to varying light intensities in terms of leaf non-structural carbohydrate allocation and the utilization of carbon, nitrogen and phosphorus to balance nutritional metabolism and adapt to environmental stress.
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Affiliation(s)
- Hongtao Xie
- National Research Station of Eastern China Coastal Forest Ecosystem, Research Institute of Subtropical Forestry, Chinese Academy of Forestry, Hangzhou, 311400, China.
| | - Mukui Yu
- National Research Station of Eastern China Coastal Forest Ecosystem, Research Institute of Subtropical Forestry, Chinese Academy of Forestry, Hangzhou, 311400, China
| | - Xiangrong Cheng
- National Research Station of Eastern China Coastal Forest Ecosystem, Research Institute of Subtropical Forestry, Chinese Academy of Forestry, Hangzhou, 311400, China.
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Tramontin DP, Gressler PD, Rörig LR, Derner RB, Pereira-Filho J, Radetski CM, Quadri MB. Growth modeling of the green microalga Scenedesmus obliquus in a hybrid photobioreactor as a practical tool to understand both physical and biochemical phenomena in play during algae cultivation. Biotechnol Bioeng 2017; 115:965-977. [PMID: 29205724 DOI: 10.1002/bit.26510] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2017] [Revised: 11/13/2017] [Accepted: 11/28/2017] [Indexed: 11/08/2022]
Abstract
In recent years, numerous studies have justified the use of microalgae as a sustainable alternative for the generation of different types of fuels, food supplementation, and cosmetics, as well as bioremediation processes. To improve the cost/benefit ratio of microalgae mass production, many culture systems have been built and upgraded. Mathematical modeling the growth of different species in different systems has become an efficient and practical tool to understand both physical and biochemical phenomena in play during algae cultivation. In addition, growth modeling can guide design changes that lead to process optimization. In the present work, growth of the green microalga Scenedesmus obliquus was modeled in a hybrid photobioreactor that combines the characteristics of tubular photobioreactors (TPB) with thin-layer cascades (TLC). The system showed productivity greater than 8.0 g m-2 day-1 (dry mass) for CO2 -fed cultures, and the model proved to be an accurate representation of experimental data with R2 greater than 0.7 for all cases under variable conditions of temperature and irradiance to determine subsystem efficiency. Growth modeling also allowed growth prediction relative to the operating conditions of TLC, making it useful for estimating the system given other irradiance and temperature conditions, as well as other microalgae species.
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Affiliation(s)
- Deise P Tramontin
- Laboratório de Sistemas Porosos, UFSC, Universidade Federal de Santa Catarina, Florianópolis, Santa Catarina, Brazil
| | - Pablo D Gressler
- Laboratório de Ficologia, UFSC, Universidade Federal de Santa Catarina, Florianópolis, Santa Catarina, Brazil
| | - Leonardo R Rörig
- Laboratório de Ficologia, UFSC, Universidade Federal de Santa Catarina, Florianópolis, Santa Catarina, Brazil
| | - Roberto B Derner
- Laboratório de Cultivo de Algas, UFSC, Universidade Federal de Santa Catarina, Florianópolis, Santa Catarina, Brazil
| | - Jurandir Pereira-Filho
- Laboratório de Oceanografia Química, UNIVALI, Universidade do Vale do Itajaí, Itajaí, Santa Catarina, Brazil
| | - Claudemir M Radetski
- Laboratório de Remediação Ambiental, UNIVALI, Universidade do Vale do Itajaí, Itajaí, Santa Catarina, Brazil
| | - Marintho B Quadri
- Laboratório de Sistemas Porosos, UFSC, Universidade Federal de Santa Catarina, Florianópolis, Santa Catarina, Brazil
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Zhang R, Kong Z, Chen S, Ran Z, Ye M, Xu J, Zhou C, Liao K, Cao J, Yan X. The comparative study for physiological and biochemical mechanisms of Thalassiosira pseudonana and Chaetoceros calcitrans in response to different light intensities. ALGAL RES 2017. [DOI: 10.1016/j.algal.2017.08.026] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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A four state parametric model for the kinetics of the non-photochemical quenching in Photosystem II. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2017; 1858:854-864. [PMID: 28801049 DOI: 10.1016/j.bbabio.2017.08.004] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/27/2017] [Revised: 07/12/2017] [Accepted: 08/05/2017] [Indexed: 11/20/2022]
Abstract
The phenomenon of non-photochemical quenching (NPQ) was studied in spinach chloroplasts using pulse amplitude modulated (PAM) fluorometry. We present a new analysis method which describes the observed fluorescence quantum yield as the sum of the product of four different states of PSII and their corresponding quantum yields. These four distinct states are PSII in the quenched or unquenched state, and with its reaction center either open or closed depending upon the reduction of the QA site. With this method we can describe the dynamics of the NPQ induction and recovery as well as quantify the percentage of photoinactivated RC throughout the measurement. We show that after one cycle of quenching followed by a period of recovery, approximately 8-9% of the RC are photoinactivated, after two cycles of illumination this number becomes 15-17%. The recovery from the quenching appeared with rates of (50s)-1 and (1h)-1. The new analysis method presented here is flexible, allowing it to be applied to any type of PAM fluorometry protocol. The method allows to quantitatively compare qualitatively different PAM curves on the basis of statistically relevant fitting parameters and to quantify quenching dynamics and photoinactivation. Moreover, the results presented here demonstrate that the analysis of a single PAM fluorometry quenching experiment can already provide information on the relative quantum yield of the four different states of PSII for the intact chloroplasts - something no other form of spectroscopy could provide in a single measurement.
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Cantrell M, Peers G. A mutant of Chlamydomonas without LHCSR maintains high rates of photosynthesis, but has reduced cell division rates in sinusoidal light conditions. PLoS One 2017. [PMID: 28644828 PMCID: PMC5482440 DOI: 10.1371/journal.pone.0179395] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
The LHCSR protein belongs to the light harvesting complex family of pigment-binding proteins found in oxygenic photoautotrophs. Previous studies have shown that this complex is required for the rapid induction and relaxation of excess light energy dissipation in a wide range of eukaryotic algae and moss. The ability of cells to rapidly regulate light harvesting between this dissipation state and one favoring photochemistry is believed to be important for reducing oxidative stress and maintaining high photosynthetic efficiency in a rapidly changing light environment. We found that a mutant of Chlamydomonas reinhardtii lacking LHCSR, npq4lhcsr1, displays minimal photoinhibition of photosystem II and minimal inhibition of short term oxygen evolution when grown in constant excess light compared to a wild type strain. We also investigated the impact of no LHCSR during growth in a sinusoidal light regime, which mimics daily changes in photosynthetically active radiation. The absence of LHCSR correlated with a slight reduction in the quantum efficiency of photosystem II and a stimulation of the maximal rates of photosynthesis compared to wild type. However, there was no reduction in carbon accumulation during the day. Another novel finding was that npq4lhcsr1 cultures underwent fewer divisions at night, reducing the overall growth rate compared to the wild type. Our results show that the rapid regulation of light harvesting mediated by LHCSR is required for high growth rates, but it is not required for efficient carbon accumulation during the day in a sinusoidal light environment. This finding has direct implications for engineering strategies directed at increasing photosynthetic productivity in mass cultures.
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Affiliation(s)
- Michael Cantrell
- Department of Biology, Colorado State University, Fort Collins, CO, United States of America
| | - Graham Peers
- Department of Biology, Colorado State University, Fort Collins, CO, United States of America
- * E-mail:
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Abstract
Desertification is currently a major concern, and vast regions have already been devastated in the arid zones of many countries. Combined application of cyanobacteria with soil fixing chemicals is a novel method of restoring desertified areas. Three cyanobacteria, Nostoc sp. Vaucher ex Bornet & Flahault, Phormidium sp. Kützing ex Gomont and Scytonema arcangeli Bornet ex Flahault were isolated and tested in this study. Tacki-SprayTM (TKS7), which consists of bio-polysaccharides and tackifiers, was used as a soil fixing agent. In addition, superabsorbent polymer (SAP) was applied to the soil as a water-holding material and nutrient supplement. Application of cyanobacteria with superabsorbent polymer and TKS7 (CST) remarkably improved macro-aggregate stability against water and erodibility against wind after 12 months of inoculation when compared to the control soil. The mean weight diameter and threshold friction velocity of the CST treated soil were found to be 75% and 88% of those of the approximately 20-year-old natural cyanobacterial crust (N-BSC), respectively, while these values were 68% and 73% of those of the N-BSC soil after a single treatment of cyanobacteria alone (CY). Interestingly, biological activities of CST were similar to those of CY. Total carbohydrate contents, cyanobacterial biomass, microbial biomass, soil respiration, carbon fixation and effective quantum yield of CST treated soil were enhanced by 50–100% of the N-BSC, while those of control soil were negligible. Our results suggest that combined application of cyanobacteria with soil fixing chemicals can rapidly develop cyanobacterial crust formation in the field within 12 months. The physical properties and biological activities of the inoculated cyanobacterial crust were stable during the study period. The novel method presented herein serves as another approach for combating desertification in arid regions.
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Affiliation(s)
- Chan-Ho Park
- Korean Lichen Research Institute, Sunchon National University, 255 Jungang-Ro, Suncheon, Korea
| | - Xin Rong Li
- Cold and Arid Regions Environmental & Engineering Research Institute, Chinese Academy of Sciences, Lanzhou, China
| | - Yang Zhao
- Cold and Arid Regions Environmental & Engineering Research Institute, Chinese Academy of Sciences, Lanzhou, China
| | - Rong Liang Jia
- Cold and Arid Regions Environmental & Engineering Research Institute, Chinese Academy of Sciences, Lanzhou, China
| | - Jae-Seoun Hur
- Korean Lichen Research Institute, Sunchon National University, 255 Jungang-Ro, Suncheon, Korea
- * E-mail:
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Remmers IM, Martens DE, Wijffels RH, Lamers PP. Dynamics of triacylglycerol and EPA production in Phaeodactylum tricornutum under nitrogen starvation at different light intensities. PLoS One 2017; 12:e0175630. [PMID: 28403203 PMCID: PMC5389818 DOI: 10.1371/journal.pone.0175630] [Citation(s) in RCA: 54] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2017] [Accepted: 03/29/2017] [Indexed: 01/02/2023] Open
Abstract
Lipid production in microalgae is highly dependent on the applied light intensity. However, for the EPA producing model-diatom Phaeodactylum tricornutum, clear consensus on the impact of incident light intensity on lipid productivity is still lacking. This study quantifies the impact of different incident light intensities on the biomass, TAG and EPA yield on light in nitrogen starved batch cultures of P. tricornutum. The maximum biomass concentration and maximum TAG and EPA contents were found to be independent of the applied light intensity. The lipid yield on light was reduced at elevated light intensities (>100 μmol m-2 s-1). The highest TAG yield on light (112 mg TAG molph-1) was found at the lowest light intensity tested (60 μmol m-2 s-1), which is still relatively low to values reported in literature for other algae. Furthermore, mass balance analysis showed that the EPA fraction in TAG may originate from photosynthetic membrane lipids.
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Affiliation(s)
- Ilse M. Remmers
- Bioprocess Engineering & AlgaePARC, Wageningen University and Research, Wageningen, The Netherlands
- * E-mail:
| | - Dirk E. Martens
- Bioprocess Engineering & AlgaePARC, Wageningen University and Research, Wageningen, The Netherlands
| | - René H. Wijffels
- Bioprocess Engineering & AlgaePARC, Wageningen University and Research, Wageningen, The Netherlands
- Biosciences and Aquaculture, Nord University, Bodø, Norway
| | - Packo P. Lamers
- Bioprocess Engineering & AlgaePARC, Wageningen University and Research, Wageningen, The Netherlands
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Leboulanger C, Agogué H, Bernard C, Bouvy M, Carré C, Cellamare M, Duval C, Fouilland E, Got P, Intertaglia L, Lavergne C, Le Floc’h E, Roques C, Sarazin G. Microbial Diversity and Cyanobacterial Production in Dziani Dzaha Crater Lake, a Unique Tropical Thalassohaline Environment. PLoS One 2017; 12:e0168879. [PMID: 28045976 PMCID: PMC5207672 DOI: 10.1371/journal.pone.0168879] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2016] [Accepted: 12/07/2016] [Indexed: 11/18/2022] Open
Abstract
This study describes, for the first time, the water chemistry and microbial diversity in Dziani Dzaha, a tropical crater lake located on Mayotte Island (Comoros archipelago, Western Indian Ocean). The lake water had a high level of dissolved matter and high alkalinity (10.6-14.5 g L-1 eq. CO32-, i.e. 160-220 mM compare to around 2-2.5 in seawater), with salinity up to 52 psu, 1.5 higher than seawater. Hierarchical clustering discriminated Dziani Dzaha water from other alkaline, saline lakes, highlighting its thalassohaline nature. The phytoplankton biomass was very high, with a total chlorophyll a concentration of 524 to 875 μg chl a L-1 depending on the survey, homogeneously distributed from surface to bottom (4 m). Throughout the whole water column the photosynthetic biomass was dominated (>97% of total biovolume) by the filamentous cyanobacteria Arthrospira sp. with a straight morphotype. In situ daily photosynthetic oxygen production ranged from 17.3 to 22.2 g O2 m-2 d-1, consistent with experimental production / irradiance measurements and modeling. Heterotrophic bacterioplankton was extremely abundant, with cell densities up to 1.5 108 cells mL-1 in the whole water column. Isolation and culture of 59 Eubacteria strains revealed the prevalence of alkaliphilic and halophilic organisms together with taxa unknown to date, based on 16S rRNA gene analysis. A single cloning-sequencing approach using archaeal 16S rDNA gene primers unveiled the presence of diverse extremophilic Euryarchaeota. The water chemistry of Dziani Dzaha Lake supports the hypothesis that it was derived from seawater and strongly modified by geological conditions and microbial activities that increased the alkalinity. Dziani Dzaha has a unique consortium of cyanobacteria, phytoplankton, heterotrophic Eubacteria and Archaea, with very few unicellular protozoa, that will deserve further deep analysis to unravel its uncommon diversity. A single taxon, belonging to the genus Arthrospira, was found responsible for almost all photosynthetic primary production.
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Affiliation(s)
| | - Hélène Agogué
- UMR LIENSs, Centre National de la Recherche Scientifique, La Rochelle, France
| | - Cécile Bernard
- UMR MCAM, Muséum National d’Histoire Naturelle, Paris, France
| | - Marc Bouvy
- UMR MARBEC, Institut de Recherche pour le Développement, Sète-Montpellier, France
| | - Claire Carré
- UMR MARBEC, Institut de Recherche pour le Développement, Sète-Montpellier, France
| | - Maria Cellamare
- UMR MCAM, Muséum National d’Histoire Naturelle, Paris, France
| | - Charlotte Duval
- UMR MCAM, Muséum National d’Histoire Naturelle, Paris, France
| | - Eric Fouilland
- UMR MARBEC, Centre National de la Recherche Scientifique, Sète-Montpellier, France
| | - Patrice Got
- UMR MARBEC, Centre National de la Recherche Scientifique, Sète-Montpellier, France
| | - Laurent Intertaglia
- Observatoire Océanologique de Banyuls-sur-Mer, Université Pierre et Marie Curie, Banyuls-sur-Mer, France
| | - Céline Lavergne
- UMR LIENSs, Centre National de la Recherche Scientifique, La Rochelle, France
| | - Emilie Le Floc’h
- UMR MARBEC, Centre National de la Recherche Scientifique, Sète-Montpellier, France
| | - Cécile Roques
- UMR MARBEC, Centre National de la Recherche Scientifique, Sète-Montpellier, France
| | - Gérard Sarazin
- UMR7154 Institut de Physique du Globe de Paris, Université Paris Diderot, Paris, France
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Vadiveloo A, Moheimani N, Kosterink NR, Cosgrove J, Parlevliet D, Gonzalez-Garcia C, Lubián LM. Photosynthetic performance of two Nannochloropsis spp. under different filtered light spectra. ALGAL RES 2016. [DOI: 10.1016/j.algal.2016.08.014] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
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Ritchie RJ, Mekjinda N. Arsenic toxicity in the water weed Wolffia arrhiza measured using Pulse Amplitude Modulation Fluorometry (PAM) measurements of photosynthesis. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2016; 132:178-85. [PMID: 27318559 DOI: 10.1016/j.ecoenv.2016.06.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/06/2015] [Revised: 06/02/2016] [Accepted: 06/03/2016] [Indexed: 05/13/2023]
Abstract
Accumulation of arsenic in plants is a serious South-east Asian environmental problem. Photosynthesis in the small aquatic angiosperm Wolffia arrhiza is very sensitive to arsenic toxicity, particularly in water below pH 7 where arsenite (As (OH)3) (AsIII) is the dominant form; at pH >7 AsO4(2-) (As(V) predominates). A blue-diode PAM (Pulse Amplitude Fluorometer) machine was used to monitor photosynthesis in Wolffia. Maximum gross photosynthesis (Pgmax) and not maximum yield (Ymax) is the most reliable indicator of arsenic toxicity. The toxicity of arsenite As(III) and arsenate (H2AsO4(2-)) As(V) vary with pH. As(V) was less toxic than As(III) at both pH 5 and pH 8 but both forms of arsenic were toxic (>90% inhibition) at below 0.1molm(-3) when incubated in arsenic for 24h. Arsenite toxicity was apparent after 1h based on Pgmax and gradually increased over 7h but there was no apparent effect on Ymax or photosynthetic efficiency (α0).
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Affiliation(s)
- Raymond J Ritchie
- Tropical Plant Biology, Technology and Environment, Prince of Songkla University Phuket, Vichitsongkram Rd, Kathu, Phuket 83120, Thailand.
| | - Nutsara Mekjinda
- Chemi Nano Biotech, Department of Biotechnology, Faculty of Science, Mahidol University, Bangkok 10400, Thailand.
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Characterization of Co-Cultivation of Cyanobacteria on Growth, Productions of Polysaccharides and Extracellular Proteins, Nitrogenase Activity, and Photosynthetic Activity. Appl Biochem Biotechnol 2016; 181:340-349. [PMID: 27544771 DOI: 10.1007/s12010-016-2215-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2016] [Accepted: 08/12/2016] [Indexed: 10/21/2022]
Abstract
Cyanobacteria as biofertilizers are benefit to reduce the use of chemical fertilizers and reestablish the ecological system in soil. In general, several strains of cyanobacteria were involved in the biofertilizers. The co-cultivation of cyanobacteria were characterized on growth profile, production of polysaccharides and extracellular proteins, nitrogenase activity, and photosynthetic activity for three selected N2-fixing cyanobacteria, Anabaena cylindrica (B1611 and F243) and Nostoc sp. (F280). After eight-day culture, the highest dry weights were obtained in F280 pure culture and co-cultivation of B1611 and F280. Higher production of extracellular proteins and cell-bonding polysaccharides (CPS) were observed in co-cultivations compared with pure culture. The highest released polysaccharides (RPS) contents were obtained in pure culture of F280 and co-cultivation of F280 and F243. Galactose and glucose were major components of CPS and RPS in all samples. Trehalose was a specific component of RPS in F280 pure culture. Based on the monosaccharide contents of CPS and RPS, F280 was the dominant species in the related treatments of co-cultivation. The nitrogenase activities in all treatments exhibited a sharp rise at the late stage while a significant decrease existed when three cyanobacteria strains were mixed. Photosynthetic activities for all treatments were determined with rapid light curve, and the related parameters were estimated.
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Microalgae growth kinetic model based on the PSII quantum yield and its utilization in the operational curves construction. ALGAL RES 2016. [DOI: 10.1016/j.algal.2016.05.020] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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Baptista MS, Miller RJ, Halewood ER, Hanna SK, Almeida CMR, Vasconcelos VM, Keller AA, Lenihan HS. Impacts of Silver Nanoparticles on a Natural Estuarine Plankton Community. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2015; 49:12968-12974. [PMID: 26444256 DOI: 10.1021/acs.est.5b03285] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Potential effects of metal nanoparticles on aquatic organisms and food webs are hard to predict from the results of single-species tests under controlled laboratory conditions, and more realistic exposure experiments are rarely conducted. We tested whether silver nanoparticles (Ag NPs) had an impact on zooplankton grazing on their prey, specifically phytoplankton and bacterioplankton populations. If Ag NPs directly reduced the abundance of prey, thereby causing the overall rate of grazing by their predators to decrease, a cascading effect on a planktonic estuarine food web would be seen. Our results show that the growth rates of both phytoplankton and bacterioplankton populations were significantly reduced by Ag NPs at concentrations of ≥500 μg L(-1). At the same time, grazing rates on these populations tended to decline with exposure to Ag NPs. Therefore, Ag NPs did not cause a cascade of effects through the food web but impacted a specific trophic level. Photosynthetic efficiency of the phytoplankton was significantly reduced at Ag NPs concentrations of ≥500 μg L(-1). These effects did not occur at relatively low concentrations of Ag that are often toxic to single species of bacteria and other organisms, suggesting that the impacts of Ag NP exposure may not be apparent at environmentally relevant concentrations due to compensatory processes at the community level.
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Affiliation(s)
- Mafalda S Baptista
- CIIMAR/CIMAR, Centro Interdisciplinar de Investigação Marinha e Ambiental, Universidade do Porto , Porto, Portugal
| | | | | | | | - C Marisa R Almeida
- CIIMAR/CIMAR, Centro Interdisciplinar de Investigação Marinha e Ambiental, Universidade do Porto , Porto, Portugal
| | - Vitor M Vasconcelos
- CIIMAR/CIMAR, Centro Interdisciplinar de Investigação Marinha e Ambiental, Universidade do Porto , Porto, Portugal
- Departamento de Biologia, Faculdade de Ciências, Universidade do Porto , Porto, Portugal
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Ritchie RJ, Mekjinda N. Measurement of Photosynthesis Using PAM Technology in a Purple Sulfur BacteriumThermochromatium tepidum(Chromatiaceae). Photochem Photobiol 2015; 91:350-8. [DOI: 10.1111/php.12413] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Affiliation(s)
- Raymond J. Ritchie
- Tropical Plant Biology Unit; Faculty of Technology and Environment; Prince of Songkla University-Phuket; Kathu Thailand
| | - Nutsara Mekjinda
- Tropical Plant Biology Unit; Faculty of Technology and Environment; Prince of Songkla University-Phuket; Kathu Thailand
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Burnell OW, Connell SD, Irving AD, Watling JR, Russell BD. Contemporary reliance on bicarbonate acquisition predicts increased growth of seagrass Amphibolis antarctica in a high-CO2 world. CONSERVATION PHYSIOLOGY 2014; 2:cou052. [PMID: 27293673 PMCID: PMC4732469 DOI: 10.1093/conphys/cou052] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/09/2014] [Revised: 07/30/2014] [Accepted: 10/16/2014] [Indexed: 05/30/2023]
Abstract
Rising atmospheric CO2 is increasing the availability of dissolved CO2 in the ocean relative to HCO3 (-). Currently, many marine primary producers use HCO3 (-) for photosynthesis, but this is energetically costly. Increasing passive CO2 uptake relative to HCO3 (-) pathways could provide energy savings, leading to increased productivity and growth of marine plants. Inorganic carbon-uptake mechanisms in the seagrass Amphibolis antarctica were determined using the carbonic anhydrase inhibitor acetazolamide (AZ) and the buffer tris(hydroxymethyl)aminomethane (TRIS). Amphibolis antarctica seedlings were also maintained in current and forecasted CO2 concentrations to measure their physiology and growth. Photosynthesis of A. antarctica was significantly reduced by AZ and TRIS, indicating utilization of HCO3 (-)-uptake mechanisms. When acclimated plants were switched between CO2 treatments, the photosynthetic rate was dependent on measurement conditions but not growth conditions, indicating a dynamic response to changes in dissolved CO2 concentration, rather than lasting effects of acclimation. At forecast CO2 concentrations, seedlings had a greater maximum electron transport rate (1.4-fold), photosynthesis (2.1-fold), below-ground biomass (1.7-fold) and increase in leaf number (2-fold) relative to plants in the current CO2 concentration. The greater increase in photosynthesis (measured as O2 production) compared with the electron transport rate at forecasted CO2 concentration suggests that photosynthetic efficiency increased, possibly due to a decrease in photorespiration. Thus, it appears that the photosynthesis and growth of seagrasses reliant on energetically costly HCO3 (-) acquisition, such as A. antarctica, might increase at forecasted CO2 concentrations. Greater growth might enhance the future prosperity and rehabilitation of these important habitat-forming plants, which have experienced declines of global significance.
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Affiliation(s)
- Owen W. Burnell
- School of Earth & Environmental Sciences, University of Adelaide, Adelaide, SA 5005, Australia
| | - Sean D. Connell
- School of Earth & Environmental Sciences, University of Adelaide, Adelaide, SA 5005, Australia
| | - Andrew D. Irving
- School of Medical and Applied Sciences, Central Queensland University, Bruce Highway, Rockhampton, QLD 4702, Australia
| | - Jennifer R. Watling
- School of Earth & Environmental Sciences, University of Adelaide, Adelaide, SA 5005, Australia
| | - Bayden D. Russell
- School of Earth & Environmental Sciences, University of Adelaide, Adelaide, SA 5005, Australia
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The epiphytic fern Elaphoglossum luridum (Fée) Christ. (Dryopteridaceae) from Central and South America: morphological and physiological responses to water stress. ScientificWorldJournal 2014; 2014:817892. [PMID: 25386618 PMCID: PMC4217239 DOI: 10.1155/2014/817892] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2014] [Revised: 09/03/2014] [Accepted: 09/17/2014] [Indexed: 11/17/2022] Open
Abstract
Elaphoglossum luridum (Fée) Christ. (Dryopteridaceae) is an epiphytic fern of the Atlantic Forest (Brazil). Anatomical and physiological studies were conducted to understand how this plant responds to water stress. The E. luridum frond is coriaceus and succulent, presenting trichomes, relatively thick cuticle, and sinuous cell walls in both abaxial and adaxial epidermis. Three treatments were analyzed: control, water deficit, and abscisic acid (ABA). Physiological studies were conducted through analysis of relative water content (RWC), photosynthetic pigments, chlorophyll a fluorescence, and malate content. No changes in RWC were observed among treatments; however, significant decreases in chlorophyll a content and photosynthetic parameters, including optimal irradiance (I opt) and maximum electron transport rate (ETRmax), were determined by rapid light curves (RLC). No evidence of crassulacean acid metabolism (CAM) pathway was observed in E. luridum in response to either water deficit or exogenous application of ABA. On the other hand, malate content decreased in the E. luridum frond after ABA treatment, seeming to downregulate malate metabolism at night, possibly through tricarboxylic acid (TCA) cycle regulation.
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Rovai AS, Barufi JB, Pagliosa PR, Scherner F, Torres MA, Horta PA, Simonassi JC, Quadros DPC, Borges DLG, Soriano-Sierra EJ. Photosynthetic performance of restored and natural mangroves under different environmental constraints. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2013; 181:233-241. [PMID: 23872046 DOI: 10.1016/j.envpol.2013.06.023] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/14/2013] [Revised: 06/06/2013] [Accepted: 06/09/2013] [Indexed: 06/02/2023]
Abstract
We hypothesized that the photosynthetic performance of mangrove stands restored by the single planting of mangroves species would be lowered due to residual stressors. The photosynthetic parameters of the vegetation of three planted mangrove stands, each with a different disturbance history, were compared to reference sites and correlated with edaphic environmental variables. A permutational analysis of variance showed significant interaction when the factors were compared, indicating that the photosynthetic parameters of the restoration areas differed from the reference sites. A univariate analysis of variance showed that all the photosynthetic parameters differed between sites and treatments, except for photosynthetic efficiency (αETR). The combination of environmental variables that best explained the variations observed in the photosynthetic performance indicators were Cu, Pb and elevation disruptions. Fluorescence techniques proved efficient in revealing important physiological differences, representing a powerful tool for rapid analysis of the effectiveness of initiatives aimed at restoring coastal environments.
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Affiliation(s)
- André Scarlate Rovai
- Universidade Federal de Santa Catarina, Departamento de Ecologia e Zoologia, Campus Universitário, Trindade, 88040-900 Florianópolis, SC, Brazil.
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Scherner F, Ventura R, Barufi JB, Horta PA. Salinity critical threshold values for photosynthesis of two cosmopolitan seaweed species: providing baselines for potential shifts on seaweed assemblages. MARINE ENVIRONMENTAL RESEARCH 2013; 91:14-25. [PMID: 22705176 DOI: 10.1016/j.marenvres.2012.05.007] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/24/2012] [Revised: 05/17/2012] [Accepted: 05/22/2012] [Indexed: 06/01/2023]
Abstract
Climate change has increased precipitation in several South American regions leading to higher freshwater inputs into marine systems with potential to cause salinity declines along the coast. The current salinity profile on the southern coast of Brazil was surveyed during four years providing a baseline of the current salinity pattern in the region. Additionally, the effects of salinity decreases on the photosynthesis of the seaweeds Ulva lactuca and Sargassum stenophyllum were investigated in laboratory. Seaweeds were cultured at salinities 5, 15 and 34 and at the mean winter and summer temperatures. Photosynthetic performance was measured following 24 and 96 h from the beginning of experiment. U. lactuca remained practically unaltered by low salinities while S. stenophyllum presented declines of important photosynthetic parameters. This is due to the different regulation abilities of energy distribution at the PSII of the two species. These differences have potential to lead to seaweed community shifts.
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Affiliation(s)
- Fernando Scherner
- Universidade Federal Rural de Pernambuco, Departamento de Biologia - Área de Botânica, Programa de Pós-Graduação em Botânica, R. Dom Manoel de Medeiros, s/n, Dois Irmãos, 52171-900 Recife, PE, Brazil.
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Ritchie RJ. The Use of Solar Radiation by the Photosynthetic Bacterium,Rhodopseudomonas palustris: Model Simulation of Conditions Found in a Shallow Pond or a Flatbed Reactor. Photochem Photobiol 2013; 89:1143-62. [DOI: 10.1111/php.12124] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2013] [Accepted: 06/24/2013] [Indexed: 11/29/2022]
Affiliation(s)
- Raymond J. Ritchie
- Tropical Plant Biology Unit; Faculty of Technology and Environment; Prince of Songkla University-Phuket; Kathu; Thailand
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Aguilera A. Eukaryotic organisms in extreme acidic environments, the río tinto case. Life (Basel) 2013; 3:363-74. [PMID: 25369810 PMCID: PMC4187173 DOI: 10.3390/life3030363] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2013] [Revised: 06/07/2013] [Accepted: 06/17/2013] [Indexed: 11/17/2022] Open
Abstract
A major issue in microbial ecology is to identify the limits of life for growth and survival, and to understand the molecular mechanisms that define these limits. Thus, interest in the biodiversity and ecology of extreme environments has grown in recent years for several reasons. Some are basic and revolve around the idea that extreme environments are believed to reflect early Earth conditions. Others are related to the biotechnological potential of extremophiles. In this regard, the study of extremely acidic environments has become increasingly important since environmental acidity is often caused by microbial activity. Highly acidic environments are relatively scarce worldwide and are generally associated with volcanic activity or mining operations. For most acidic environments, low pH facilitates metal solubility, and therefore acidic waters tend to have high concentrations of heavy metals. However, highly acidic environments are usually inhabited by acidophilic and acidotolerant eukaryotic microorganisms such as algae, amoebas, ciliates, heliozoan and rotifers, not to mention filamentous fungi and yeasts. Here, we review the general trends concerning the diversity and ecophysiology of eukaryotic acidophilic microorganims, as well as summarize our latest results on this topic in one of the largest extreme acidic rivers, Río Tinto (SW, Spain).
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Affiliation(s)
- Angeles Aguilera
- Astrobiology Center, Spanish Institute for Aerospace Technologies, Carretera de Ajalvir Km 4, Torrejón de Ardoz, 28850 Madrid, Spain.
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Solovchenko A, Solovchenko O, Khozin-Goldberg I, Didi-Cohen S, Pal D, Cohen Z, Boussiba S. Probing the effects of high-light stress on pigment and lipid metabolism in nitrogen-starving microalgae by measuring chlorophyll fluorescence transients: Studies with a Δ5 desaturase mutant of Parietochloris incisa (Chlorophyta, Trebouxiophyceae). ALGAL RES 2013. [DOI: 10.1016/j.algal.2013.01.010] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Comparison of photoacclimation in twelve freshwater photoautotrophs (chlorophyte, bacillaryophyte, cryptophyte and cyanophyte) isolated from a natural community. PLoS One 2013; 8:e57139. [PMID: 23526934 PMCID: PMC3602455 DOI: 10.1371/journal.pone.0057139] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2012] [Accepted: 01/21/2013] [Indexed: 11/19/2022] Open
Abstract
Different representative of algae and cyanobacteria were isolated from a freshwater habitat and cultivated in laboratory to compare their photoacclimation capacity when exposed to a wide range of light intensity and to understand if this factor may modify natural community dominance. All species successfully acclimated to all light intensities and the response of phytoplankton to increased light intensity was similar and included a decrease of most photosynthetic pigments accompanied by an increase in photoprotective pigment content relative to Chl a. Most species also decreased their light absorption efficiency on a biovolume basis. This decrease not only resulted in a lower fraction of energy absorbed by the cell, but also to a lower transfer of energy to PSII and PSI. Furthermore, energy funnelled to PSII or PSI was also rearranged in favour of PSII. High light acclimated organisms also corresponded to high non-photochemical quenching and photosynthetic electron transport reduction state and to a low Φ'M. Thus photoacclimation processes work toward reducing the excitation pressure in high light environment through a reduction of light absorption efficiency, but also by lowering conversion efficiency. Interestingly, all species of our study followed that tendency despite being of different functional groups (colonial, flagellated, different sizes) and of different phylogeny demonstrating the great plasticity and adaptation ability of freshwater phytoplankton to their light environment. These adjustments may explain the decoupling between growth rate and photosynthesis observed above photosynthesis light saturation point for all species. Even if some species did reach higher growth rate in our conditions and thus, should dominate in natural environment with respect to light intensity, we cannot exclude that other environmental factors also influence the population dynamic and make the outcome harder to predict.
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