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Schmitt FJ, Hüls A, Moldenhauer M, Friedrich T. How electron tunneling and uphill excitation energy transfer support photochemistry in Halomicronema hongdechloris. PHOTOSYNTHESIS RESEARCH 2024; 159:273-289. [PMID: 38198121 DOI: 10.1007/s11120-023-01064-4] [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: 05/31/2023] [Accepted: 11/13/2023] [Indexed: 01/11/2024]
Abstract
Halomicronema hongdechloris, the first cyanobacterium reported to produce the red-shifted chlorophyll f (Chl f) upon acclimation to far-red light, demonstrates remarkable adaptability to diverse light conditions. The photosystem II (PS II) of this organism undergoes reversible changes in its Chl f content, ranging from practically zero under white-light culture conditions to a Chl f: Chl a ratio of up to 1:8 when exposed to far-red light (FRL) of 720-730 nm for several days. Our ps time- and wavelength-resolved fluorescence data obtained after excitation of living H. hongdechloris cells indicate that the Soret band of a far-red (FR) chlorophyll involved in charge separation absorbs around 470 nm. At 10 K, the fluorescence decay at 715-720 nm is still fast with a time constant of 165 ps indicating an efficient electron tunneling process. There is efficient excitation energy transfer (EET) from 715-720 nm to 745 nm with the latter resulting from FR Chl f, which mainly functions as light-harvesting pigment upon adaptation to FRL. From there, excitation energy reaches the primary donor in the reaction center of PS II with an energetic uphill EET mechanism inducing charge transfer. The fluorescence data are well explained with a secondary donor PD1 represented by a red-shifted Chl a molecule with characteristic fluorescence around 715 nm and a more red-shifted FR Chl f with fluorescence around 725 nm as primary donor at the ChlD1 or PD2 position.
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Affiliation(s)
- Franz-Josef Schmitt
- Department of Physics, Martin-Luther-Universität Halle-Wittenberg, Von-Danckelmann-Platz 3, 06120, Halle (Saale), Germany.
| | - Anne Hüls
- Department of Bioenergetics, Institute of Chemistry PC 14, Technische Universität Berlin, Straße des 17. Juni 135, 10623, Berlin, Germany
| | - Marcus Moldenhauer
- Department of Bioenergetics, Institute of Chemistry PC 14, Technische Universität Berlin, Straße des 17. Juni 135, 10623, Berlin, Germany
| | - Thomas Friedrich
- Department of Bioenergetics, Institute of Chemistry PC 14, Technische Universität Berlin, Straße des 17. Juni 135, 10623, Berlin, Germany
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2
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Discovery of Chlorophyll d: Isolation and Characterization of a Far-Red Cyanobacterium from the Original Site of Manning and Strain (1943) at Moss Beach, California. Microorganisms 2022; 10:microorganisms10040819. [PMID: 35456869 PMCID: PMC9029297 DOI: 10.3390/microorganisms10040819] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2022] [Revised: 04/09/2022] [Accepted: 04/11/2022] [Indexed: 11/17/2022] Open
Abstract
We have isolated a chlorophyll-d-containing cyanobacterium from the intertidal field site at Moss Beach, on the coast of Central California, USA, where Manning and Strain (1943) originally discovered this far-red chlorophyll. Here, we present the cyanobacterium’s environmental description, culturing procedure, pigment composition, ultrastructure, and full genome sequence. Among cultures of far-red cyanobacteria obtained from red algae from the same site, this strain was an epiphyte on a brown macroalgae. Its Qyin vivo absorbance peak is centered at 704–705 nm, the shortest wavelength observed thus far among the various known Acaryochloris strains. Its Chl a/Chl d ratio was 0.01, with Chl d accounting for 99% of the total Chl d and Chl a mass. TEM imagery indicates the absence of phycobilisomes, corroborated by both pigment spectra and genome analysis. The Moss Beach strain codes for only a single set of genes for producing allophycocyanin. Genomic sequencing yielded a 7.25 Mbp circular chromosome and 10 circular plasmids ranging from 16 kbp to 394 kbp. We have determined that this strain shares high similarity with strain S15, an epiphyte of red algae, while its distinct gene complement and ecological niche suggest that this strain could be the closest known relative to the original Chl d source of Manning and Strain (1943). The Moss Beach strain is designated Acaryochloris sp. (marina) strain Moss Beach.
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3
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Simkin AJ, Kapoor L, Doss CGP, Hofmann TA, Lawson T, Ramamoorthy S. The role of photosynthesis related pigments in light harvesting, photoprotection and enhancement of photosynthetic yield in planta. PHOTOSYNTHESIS RESEARCH 2022; 152:23-42. [PMID: 35064531 DOI: 10.1007/s11120-021-00892-6] [Citation(s) in RCA: 45] [Impact Index Per Article: 22.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/25/2021] [Accepted: 12/13/2021] [Indexed: 05/06/2023]
Abstract
Photosynthetic pigments are an integral and vital part of all photosynthetic machinery and are present in different types and abundances throughout the photosynthetic apparatus. Chlorophyll, carotenoids and phycobilins are the prime photosynthetic pigments which facilitate efficient light absorption in plants, algae, and cyanobacteria. The chlorophyll family plays a vital role in light harvesting by absorbing light at different wavelengths and allowing photosynthetic organisms to adapt to different environments, either in the long-term or during transient changes in light. Carotenoids play diverse roles in photosynthesis, including light capture and as crucial antioxidants to reduce photodamage and photoinhibition. In the marine habitat, phycobilins capture a wide spectrum of light and have allowed cyanobacteria and red algae to colonise deep waters where other frequencies of light are attenuated by the water column. In this review, we discuss the potential strategies that photosynthetic pigments provide, coupled with development of molecular biological techniques, to improve crop yields through enhanced light harvesting, increased photoprotection and improved photosynthetic efficiency.
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Affiliation(s)
- Andrew J Simkin
- School of Biosciences, University of Kent, Canterbury, CT2 7NJ, United Kingdom
| | - Leepica Kapoor
- School of Bio Sciences and Technology, Vellore Institute of Technology, Vellore, 632014, Tamil Nadu, India
| | - C George Priya Doss
- School of Bio Sciences and Technology, Vellore Institute of Technology, Vellore, 632014, Tamil Nadu, India
| | - Tanja A Hofmann
- OSFC, Scrivener Drive, Pinewood, Ipswich, IP8 3SU, United Kingdom
| | - Tracy Lawson
- School of Life Sciences, University of Essex, Wivenhoe Park, Colchester, CO4 3SQ, United Kingdom
| | - Siva Ramamoorthy
- School of Bio Sciences and Technology, Vellore Institute of Technology, Vellore, 632014, Tamil Nadu, India.
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4
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Elias E, Liguori N, Saga Y, Schäfers J, Croce R. Harvesting Far-Red Light with Plant Antenna Complexes Incorporating Chlorophyll d. Biomacromolecules 2021; 22:3313-3322. [PMID: 34269578 PMCID: PMC8356222 DOI: 10.1021/acs.biomac.1c00435] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2021] [Revised: 06/28/2021] [Indexed: 11/28/2022]
Abstract
Increasing the absorption cross section of plants by introducing far-red absorbing chlorophylls (Chls) has been proposed as a strategy to boost crop yields. To make this strategy effective, these Chls should bind to the photosynthetic complexes without altering their functional architecture. To investigate if plant-specific antenna complexes can provide the protein scaffold to accommodate these Chls, we have reconstituted the main light-harvesting complex (LHC) of plants LHCII in vitro and in silico, with Chl d. The results demonstrate that LHCII can bind Chl d in a number of binding sites, shifting the maximum absorption ∼25 nm toward the red with respect to the wild-type complex (LHCII with Chl a and b) while maintaining the native LHC architecture. Ultrafast spectroscopic measurements show that the complex is functional in light harvesting and excitation energy transfer. Overall, we here demonstrate that it is possible to obtain plant LHCs with enhanced far-red absorption and intact functional properties.
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Affiliation(s)
- Eduard Elias
- Department
of Physics and Astronomy and Institute for Lasers, Life and Biophotonics,
Faculty of Sciences, VU University Amsterdam, De Boelelaan 1081, 1081 HV Amsterdam, The Netherlands
| | - Nicoletta Liguori
- Department
of Physics and Astronomy and Institute for Lasers, Life and Biophotonics,
Faculty of Sciences, VU University Amsterdam, De Boelelaan 1081, 1081 HV Amsterdam, The Netherlands
| | - Yoshitaka Saga
- Department
of Physics and Astronomy and Institute for Lasers, Life and Biophotonics,
Faculty of Sciences, VU University Amsterdam, De Boelelaan 1081, 1081 HV Amsterdam, The Netherlands
- Department
of Chemistry, Faculty of Science and Engineering, Kindai University, Higashi-Osaka 577-8502, Osaka, Japan
| | - Judith Schäfers
- Department
of Physics and Astronomy and Institute for Lasers, Life and Biophotonics,
Faculty of Sciences, VU University Amsterdam, De Boelelaan 1081, 1081 HV Amsterdam, The Netherlands
| | - Roberta Croce
- Department
of Physics and Astronomy and Institute for Lasers, Life and Biophotonics,
Faculty of Sciences, VU University Amsterdam, De Boelelaan 1081, 1081 HV Amsterdam, The Netherlands
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5
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Oetama VSP, Pentzold S, Boland W. The fate of chlorophyll in phytophagous insects goes beyond nutrition. Z NATURFORSCH C 2021; 76:1-9. [PMID: 32887212 DOI: 10.1515/znc-2020-0060] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2020] [Accepted: 08/03/2020] [Indexed: 12/13/2022]
Abstract
Chlorophyll (Chl) is a natural compound that is found in all autotrophic plants. Since phytophagous insects ingest the photosynthetically active material with the plant leaves, the question arises if and how herbivores deal with Chl and its degradation products. Here we review findings on Chl degradation in phytophagous insects and highlight the role of these ubiquitous plant metabolites for plant-feeding insects. Due to the anaerobic gut of many insects, the degradation is limited to the removal of the peripheral substituents, while the tetrapyrrole core remains intact. Proteins, such as red fluorescent protein, P252 (a novel 252-kDa protein), and chlorophyllide binding protein have been reported to occur in the insect gut and might be indirectly connected to Chl degradation. Besides of an nutritional value, e.g., by taking up Mg2+ ions or by sequestration of carbon from the phytol side chain, the Chl degradation products may serve the insect, after binding to certain proteins, as antimicrobial, antifungal, and antiviral factors. The protein complexes may also confer protection against reactive oxygen species. The antibiotic potential of proteins and degradation products does not only benefit phytophagous insects but also human being in medical application of cancer treatment for instance. This review highlights these aspects from a molecular, biochemical, and ecological point of view.
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Affiliation(s)
- Vincensius S P Oetama
- Department of Bioorganic Chemistry, Max Planck Institute for Chemical Ecology, Hans-Knvll-Stra_e 8, 07745 Jena, Germany
| | - Stefan Pentzold
- Department of Bioorganic Chemistry, Max Planck Institute for Chemical Ecology, Hans-Knvll-Stra_e 8, 07745 Jena, Germany.,Friedrich Schiller University Jena, University Hospital, Am Klinikum 1, 07747 Jena, Germany
| | - Wilhelm Boland
- Department of Bioorganic Chemistry, Max Planck Institute for Chemical Ecology, Hans-Knvll-Stra_e 8, 07745 Jena, Germany
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6
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7
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Harvesting far-red light: Functional integration of chlorophyll f into Photosystem I complexes of Synechococcus sp. PCC 7002. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2020; 1861:148206. [DOI: 10.1016/j.bbabio.2020.148206] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/22/2020] [Revised: 04/01/2020] [Accepted: 04/14/2020] [Indexed: 11/18/2022]
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8
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Spectral Diversity Metrics for Detecting Oil Pollution Effects on Biodiversity in the Niger Delta. REMOTE SENSING 2019. [DOI: 10.3390/rs11222662] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Biodiversity monitoring in the Niger delta has become pertinent in view of the incessant spillages from oil production activities and the socio-economic impact of these spillages on the inhabitants who depend on the resources for their livelihood. Conventional methods of post-impact assessments are expensive, time consuming, and cause damage to the environment, as they often require the removal of affected samples/specimens for laboratory analysis. Remote sensing offers the opportunity to track biodiversity changes from space while using the spectral variability hypothesis (SVH). The SVH proposes that the species diversity of a sampled area is linearly correlated with the variability of spectral reflectance of the area. Several authors have tested the SVH on various land cover types and spatial scales; however, the present study evaluated the validity of the SVH against the backdrop of oil pollution impact on biodiversity while using vascular plant species as surrogates. Species richness and diversity indices were computed from vegetation data collected from polluted and non-polluted transects. Spectral metrics that were derived from Sentinel 2 bands and broadband vegetation indices (BVIs) using various algorithms, including averages, spread, dimension reduction, and so on, were assessed for their ability to estimate vascular plants species richness and diversity. The results showed significant differences in vegetation characteristics of polluted and control transects (H = 76.05, p-value = <0.05 for abundance and H = 170.03, p-value < 0.05 for richness). Spectral diversity metrics correlated negatively with species data on polluted transects and positively on control transects. The metrics computed using Sentinel 2A bands and vegetation indices proved to be sensitive to changes in vegetation characteristics following oil pollution. The most robust relationship was observed between the metrics and indices on control transects, whereas the weakest relationships were observed on polluted transects. Index-wise, the Simpson’s diversity index regressed better with spectral metrics (R2 > 0.5), whereas the Chao-1 richness index regressed the least (R2 < 0.5). The strength of the relationship resulted in successfully estimating species richness and diversity values of investigated transects, thereby enhancing biodiversity monitoring over time and space.
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9
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Far-Red Light Acclimation for Improved Mass Cultivation of Cyanobacteria. Metabolites 2019; 9:metabo9080170. [PMID: 31430925 PMCID: PMC6724174 DOI: 10.3390/metabo9080170] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2019] [Revised: 08/13/2019] [Accepted: 08/15/2019] [Indexed: 01/31/2023] Open
Abstract
Improving mass cultivation of cyanobacteria is a goal for industrial biotechnology. In this study, the mass cultivation of the thermophilic cyanobacterium Chlorogloeopsis fritschii was assessed for biomass production under light-emitting diode white light (LEDWL), far-red light (FRL), and combined white light and far-red light (WLFRL) adaptation. The induction of chl f was confirmed at 24 h after the transfer of culture from LEDWL to FRL. Using combined light (WLFRL), chl f, a, and d, maintained the same level of concentration in comparison to FRL conditions. However, phycocyanin and xanthophylls (echinone, caloxanthin, myxoxanthin, nostoxanthin) concentration increased 2.7–4.7 times compared to LEDWL conditions. The productivity of culture was double under WLFRL compared with LEDWL conditions. No significant changes in lipid, protein, and carbohydrate concentrations were found in the two different light conditions. The results are important for informing on optimum biomass cultivation of this species for biomass production and bioactive product development.
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10
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Schmitt FJ, Campbell ZY, Bui MV, Hüls A, Tomo T, Chen M, Maksimov EG, Allakhverdiev SI, Friedrich T. Photosynthesis supported by a chlorophyll f-dependent, entropy-driven uphill energy transfer in Halomicronema hongdechloris cells adapted to far-red light. PHOTOSYNTHESIS RESEARCH 2019; 139:185-201. [PMID: 30039357 DOI: 10.1007/s11120-018-0556-2] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/21/2018] [Accepted: 07/09/2018] [Indexed: 06/08/2023]
Abstract
The phototrophic cyanobacterium Halomicronema hongdechloris shows far-red light-induced accumulation of chlorophyll (Chl) f, but the involvement of the pigment in photosynthetic energy harvesting by photosystem (PS) II is controversially discussed. While H. hongdechloris contains negligible amounts of Chl f in white-light culture conditions, the ratio of Chl f to Chl a is reversibly changed up to 1:8 under illumination with far-red light (720-730 nm). We performed UV-Vis absorption spectroscopy, time-integrated and time-resolved fluorescence spectroscopy for the calculation of decay-associated spectra (DAS) to determine excitation energy transfer (EET) processes between photosynthetic pigments in intact H. hongdechloris filaments. In cells grown under white light, highly efficient EET occurs from phycobilisomes (PBSs) to Chl a with an apparent time constant of about 100 ps. Charge separation occurs with a typical apparent time constant of 200-300 ps from Chl a. After 3-4 days of growth under far-red light, robust Chl f content was observed in H. hongdechloris and EET from PBSs reached Chl f efficiently within 200 ps. It is proposed based on mathematical modeling by rate equation systems for EET between the PBSs and PSII and subsequent electron transfer (ET) that charge separation occurs from Chl a and excitation energy is funneled from Chl f to Chl a via an energetically uphill EET driven by entropy, which is effective because the number of Chl a molecules coupled to Chl f is at least eight- to tenfold larger than the corresponding number of Chl f molecules. The long lifetime of Chl f molecules in contact to a tenfold larger pool of Chl a molecules allows Chl f to act as an intermediate energy storage level, from which the Gibbs free energy difference between Chl f and Chl a can be overcome by taking advantage from the favorable ratio of degeneracy coefficients, which formally represents a significant entropy gain in the Eyring formulation of the Arrhenius law. Direct evidence for energetically uphill EET and charge separation in PSII upon excitation of Chl f via anti-Stokes fluorescence in far-red light-adapted H. hongdechloris cells was obtained: Excitation by 720 nm laser light resulted in robust Chl a fluorescence at 680 nm that was distinctly temperature-dependent and, notably, increased upon DCMU (3-(3,4-dichlorophenyl)-1,1-dimethylurea) treatment in far-red light-adapted cells. Thus, rather than serving as an excitation energy trap, Chl f in far-red light-adapted H. hongdechloris cells is directly contributing to oxygenic photosynthesis at PSII.
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Affiliation(s)
- Franz-Josef Schmitt
- Institute of Chemistry PC 14, Technical University of Berlin, Straße des 17. Juni 135, 10623, Berlin, Germany.
| | - Züleyha Yenice Campbell
- Institute of Chemistry PC 14, Technical University of Berlin, Straße des 17. Juni 135, 10623, Berlin, Germany
| | - Mai Vi Bui
- Institute of Chemistry PC 14, Technical University of Berlin, Straße des 17. Juni 135, 10623, Berlin, Germany
| | - Anne Hüls
- Institute of Chemistry PC 14, Technical University of Berlin, Straße des 17. Juni 135, 10623, Berlin, Germany
| | - Tatsuya Tomo
- Department of Biology, Faculty of Science, Tokyo University of Science, Kagurazaka 1-3, Shinjuku‑Ku, Tokyo, 162‑8601, Japan
| | - Min Chen
- School of Life and Environmental Sciences, University of Sydney, Sydney, NSW, 2006, Australia
| | - Eugene G Maksimov
- Department of Biophysics, Faculty of Biology, Lomonosov Moscow State University, Leninskye Gory 1, bld. 24, Moscow, Russian Federation, 119991
| | - Suleyman I Allakhverdiev
- Faculty of Biology, M.V. Lomonosov Moscow State University, Moscow, Russian Federation, 119992
- Bionanotechnology Laboratory, Institute of Molecular Biology and Biotechnology, Azerbaijan National Academy of Sciences, Matbuat Avenue 2a, 1073, Baku, Azerbaijan
- Moscow Institute of Physics and Technology, Institutsky Lane 9, Dolgoprudny, Moscow Region, Russian Federation, 141700
- Controlled Photobiosynthesis Laboratory, Institute of Plant Physiology, Russian Academy of Sciences, Botanicheskaya Street 35, Moscow, Russian Federation, 127276
- Institute of Basic Biological Problems, Russian Academy of Sciences, Pushchino, Moscow Region, Russian Federation, 142290
| | - Thomas Friedrich
- Institute of Chemistry PC 14, Technical University of Berlin, Straße des 17. Juni 135, 10623, Berlin, Germany.
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11
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Chen Q, Arents J, Schuurmans JM, Ganapathy S, de Grip WJ, Cheregi O, Funk C, dos Santos FB, Hellingwerf KJ. Combining retinal-based and chlorophyll-based (oxygenic) photosynthesis: Proteorhodopsin expression increases growth rate and fitness of a ∆PSI strain of Synechocystis sp. PCC6803. Metab Eng 2019; 52:68-76. [DOI: 10.1016/j.ymben.2018.11.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2018] [Revised: 11/09/2018] [Accepted: 11/10/2018] [Indexed: 11/28/2022]
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12
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Kume A, Akitsu T, Nasahara KN. Why is chlorophyll b only used in light-harvesting systems? JOURNAL OF PLANT RESEARCH 2018; 131:961-972. [PMID: 29992395 PMCID: PMC6459968 DOI: 10.1007/s10265-018-1052-7] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/08/2018] [Accepted: 06/13/2018] [Indexed: 05/09/2023]
Abstract
Chlorophylls (Chl) are important pigments in plants that are used to absorb photons and release electrons. There are several types of Chls but terrestrial plants only possess two of these: Chls a and b. The two pigments form light-harvesting Chl a/b-binding protein complexes (LHC), which absorb most of the light. The peak wavelengths of the absorption spectra of Chls a and b differ by c. 20 nm, and the ratio between them (the a/b ratio) is an important determinant of the light absorption efficiency of photosynthesis (i.e., the antenna size). Here, we investigated why Chl b is used in LHCs rather than other light-absorbing pigments that can be used for photosynthesis by considering the solar radiation spectrum under field conditions. We found that direct and diffuse solar radiation (PARdir and PARdiff, respectively) have different spectral distributions, showing maximum spectral photon flux densities (SPFD) at c. 680 and 460 nm, respectively, during the daytime. The spectral absorbance spectra of Chls a and b functioned complementary to each other, and the absorbance peaks of Chl b were nested within those of Chl a. The absorption peak in the short wavelength region of Chl b in the proteinaceous environment occurred at c. 460 nm, making it suitable for absorbing the PARdiff, but not suitable for avoiding the high spectral irradiance (SIR) waveband of PARdir. In contrast, Chl a effectively avoided the high SPFD and/or high SIR waveband. The absorption spectra of photosynthetic complexes were negatively correlated with SPFD spectra, but LHCs with low a/b ratios were more positively correlated with SIR spectra. These findings indicate that the spectra of the photosynthetic pigments and constructed photosystems and antenna proteins significantly align with the terrestrial solar spectra to allow the safe and efficient use of solar radiation.
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Affiliation(s)
- Atsushi Kume
- Faculty of Agriculture, Kyushu University, 6-10-1 Hakozaki, Higashi-ku, Fukuoka, 812-8581, Japan.
| | - Tomoko Akitsu
- Faculty of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, 305-8572, Japan
| | - Kenlo Nishida Nasahara
- Faculty of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, 305-8572, Japan
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13
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Takizawa K, Minagawa J, Tamura M, Kusakabe N, Narita N. Red-edge position of habitable exoplanets around M-dwarfs. Sci Rep 2017; 7:7561. [PMID: 28790357 PMCID: PMC5548919 DOI: 10.1038/s41598-017-07948-5] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2016] [Accepted: 07/07/2017] [Indexed: 11/09/2022] Open
Abstract
One of the possible signs of life on distant habitable exoplanets is the red-edge, which is a rise in the reflectivity of planets between visible and near-infrared (NIR) wavelengths. Previous studies suggested the possibility that the red-edge position for habitable exoplanets around M-dwarfs may be shifted to a longer wavelength than that for Earth. We investigated plausible red-edge position in terms of the light environment during the course of the evolution of phototrophs. We show that phototrophs on M-dwarf habitable exoplanets may use visible light when they first evolve in the ocean and when they first colonize the land. The adaptive evolution of oxygenic photosynthesis may eventually also use NIR radiation, by one of two photochemical reaction centers, with the other center continuing to use visible light. These “two-color” reaction centers can absorb more photons, but they will encounter difficulty in adapting to drastically changing light conditions at the boundary between land and water. NIR photosynthesis can be more productive on land, though its evolution would be preceded by the Earth-type vegetation. Thus, the red-edge position caused by photosynthetic organisms on habitable M-dwarf exoplanets could initially be similar to that on Earth and later move to a longer wavelength.
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Affiliation(s)
- Kenji Takizawa
- Astrobiology Center, National Institutes of Natural Sciences, 2-21-1 Osawa, Mitaka, Tokyo, 181-8588, Japan.,National Institute for Basic Biology, National Institutes of Natural Sciences, 38 Nishigonaka, Myodaiji, Okazaki, Aichi, 444-8585, Japan
| | - Jun Minagawa
- National Institute for Basic Biology, National Institutes of Natural Sciences, 38 Nishigonaka, Myodaiji, Okazaki, Aichi, 444-8585, Japan
| | - Motohide Tamura
- Astrobiology Center, National Institutes of Natural Sciences, 2-21-1 Osawa, Mitaka, Tokyo, 181-8588, Japan.,Department of Astronomy, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan.,National Astronomical Observatory of Japan, National Institutes of Natural Sciences, 2-21-1 Osawa, Mitaka, Tokyo, 181-8588, Japan
| | - Nobuhiko Kusakabe
- Astrobiology Center, National Institutes of Natural Sciences, 2-21-1 Osawa, Mitaka, Tokyo, 181-8588, Japan.,National Astronomical Observatory of Japan, National Institutes of Natural Sciences, 2-21-1 Osawa, Mitaka, Tokyo, 181-8588, Japan
| | - Norio Narita
- Astrobiology Center, National Institutes of Natural Sciences, 2-21-1 Osawa, Mitaka, Tokyo, 181-8588, Japan. .,Department of Astronomy, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan. .,National Astronomical Observatory of Japan, National Institutes of Natural Sciences, 2-21-1 Osawa, Mitaka, Tokyo, 181-8588, Japan.
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14
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Badshah SL, Mabkhot Y, Al-Showiman SS. Photosynthesis at the far-red region of the spectrum in Acaryochloris marina. Biol Res 2017; 50:16. [PMID: 28526061 PMCID: PMC5438491 DOI: 10.1186/s40659-017-0120-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2016] [Accepted: 04/05/2017] [Indexed: 11/21/2022] Open
Abstract
Acaryochloris marina is an oxygenic cyanobacterium that utilizes far-red light for photosynthesis. It has an expanded genome, which helps in its adaptability to the environment, where it can survive on low energy photons. Its major light absorbing pigment is chlorophyll d and it has α-carotene as a major carotenoid. Light harvesting antenna includes the external phycobilin binding proteins, which are hexameric rods made of phycocyanin and allophycocyanins, while the small integral membrane bound chlorophyll binding proteins are also present. There is specific chlorophyll a molecule in both the reaction center of Photosystem I (PSI) and PSII, but majority of the reaction center consists of chlorophyll d. The composition of the PSII reaction center is debatable especially the role and position of chlorophyll a in it. Here we discuss the photosystems of this bacterium and its related biology.
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Affiliation(s)
- Syed Lal Badshah
- Department of Chemistry, Islamia College University Peshawar, Peshawar, 25120, Khyber Pakhtunkhwa, Pakistan.
- Department of Biochemistry, Abdul Wali Khan University Mardan, Mardan, 23200, Pakhtunkhwa, Pakistan.
| | - Yahia Mabkhot
- Department of Chemistry, College of Science, King Saud University, Riyad, Saudi Arabia.
| | - Salim S Al-Showiman
- Department of Chemistry, College of Science, King Saud University, Riyad, Saudi Arabia.
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Allakhverdiev SI, Kreslavski VD, Zharmukhamedov SK, Voloshin RA, Korol'kova DV, Tomo T, Shen JR. Chlorophylls d and f and Their Role in Primary Photosynthetic Processes of Cyanobacteria. BIOCHEMISTRY (MOSCOW) 2017; 81:201-12. [PMID: 27262189 DOI: 10.1134/s0006297916030020] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The finding of unique Chl d- and Chl f-containing cyanobacteria in the last decade was a discovery in the area of biology of oxygenic photosynthetic organisms. Chl b, Chl c, and Chl f are considered to be accessory pigments found in antennae systems of photosynthetic organisms. They absorb energy and transfer it to the photosynthetic reaction center (RC), but do not participate in electron transport by the photosynthetic electron transport chain. However, Chl d as well as Chl a can operate not only in the light-harvesting complex, but also in the photosynthetic RC. The long-wavelength (Qy) Chl d and Chl f absorption band is shifted to longer wavelength (to 750 nm) compared to Chl a, which suggests the possibility for oxygenic photosynthesis in this spectral range. Such expansion of the photosynthetically active light range is important for the survival of cyanobacteria when the intensity of light not exceeding 700 nm is attenuated due to absorption by Chl a and other pigments. At the same time, energy storage efficiency in photosystem 2 for cyanobacteria containing Chl d and Chl f is not lower than that of cyanobacteria containing Chl a. Despite great interest in these unique chlorophylls, many questions related to functioning of such pigments in primary photosynthetic processes are still not elucidated. This review describes the latest advances in the field of Chl d and Chl f research and their role in primary photosynthetic processes of cyanobacteria.
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Affiliation(s)
- S I Allakhverdiev
- Timiryazev Institute of Plant Physiology, Russian Academy of Sciences, Moscow, 127276, Russia.
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16
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Knör G. Recent progress in homogeneous multielectron transfer photocatalysis and artificial photosynthetic solar energy conversion. Coord Chem Rev 2015. [DOI: 10.1016/j.ccr.2014.09.013] [Citation(s) in RCA: 58] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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17
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Itoh S, Ohno T, Noji T, Yamakawa H, Komatsu H, Wada K, Kobayashi M, Miyashita H. Harvesting Far-Red Light by Chlorophyll f in Photosystems I and II of Unicellular Cyanobacterium strain KC1. PLANT & CELL PHYSIOLOGY 2015; 56:2024-2034. [PMID: 26320210 DOI: 10.1093/pcp/pcv122] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/13/2015] [Accepted: 08/14/2015] [Indexed: 06/04/2023]
Abstract
Cells of a unicellular cyanobacterium strain KC1, which were collected from Japanese fresh water Lake Biwa, formed chlorophyll (Chl) f at 6.7%, Chl a' at 2.0% and pheophytin a at 0.96% with respect to Chl a after growth under 740 nm light. The far-red-acclimated cells (Fr cells) formed extra absorption bands of Chl f at 715 nm in addition to the major Chl a band. Fluorescence lifetimes were measured. The 405-nm laser flash, which excites mainly Chl a in photosystem I (PSI), induced a fast energy transfer to multiple fluorescence bands at 720-760 and 805 nm of Chl f at 77 K in Fr cells with almost no PSI-red-Chl a band. The 630-nm laser flash, which mainly excited photosystem II (PSII) through phycocyanin, revealed fast energy transfer to another set of Chl f bands at 720-770 and 810 nm as well as to the 694-nm Chl a fluorescence band. The 694-nm band did not transfer excitation energy to Chl f. Therefore, Chl a in PSI, and phycocyanin in PSII of Fr cells transferred excitation energy to different sets of Chl f molecules. Multiple Chl f forms, thus, seem to work as the far-red antenna both in PSI and PSII. A variety of cyanobacterial species, phylogenically distant from each other, seems to use a Chl f antenna in far-red environments, such as under dense biomats, in colonies, or under far-red LED light.
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Affiliation(s)
- Shigeru Itoh
- Center for Gene Research, Nagoya University, Furo-cho, Chikusa, Nagoya 464-8602, Japan
| | - Tomoki Ohno
- Graduate School of Human and Environmental Studies, Kyoto University, Kyoto 606-8501, Japan
| | - Tomoyasu Noji
- Department of Frontier Materials, Graduate School of Engineering, Nagoya Institute of Technology, Gokiso-cho, Showa, Nagoya 466-8555, Japan
| | - Hisanori Yamakawa
- Graduate School of Bioagricultural Sciences, Nagoya University, Furo-cho, Chikusa, Nagoya 464-8602, Japan
| | - Hirohisa Komatsu
- Division of Materials Science, Faculty of Pure and Applied Science, University of Tsukuba, Tsukuba, Ibaraki 305-8573, Japan
| | - Katsuhiro Wada
- Division of Materials Science, Faculty of Pure and Applied Science, University of Tsukuba, Tsukuba, Ibaraki 305-8573, Japan
| | - Masami Kobayashi
- Division of Materials Science, Faculty of Pure and Applied Science, University of Tsukuba, Tsukuba, Ibaraki 305-8573, Japan
| | - Hideaki Miyashita
- Graduate School of Human and Environmental Studies, Kyoto University, Kyoto 606-8501, Japan Graduate School of Global and Environmental Studies, Kyoto University, Kyoto 606-8501, Japan
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18
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Cotton CAR, Douglass JS, De Causmaecker S, Brinkert K, Cardona T, Fantuzzi A, Rutherford AW, Murray JW. Photosynthetic constraints on fuel from microbes. Front Bioeng Biotechnol 2015; 3:36. [PMID: 25853129 PMCID: PMC4364286 DOI: 10.3389/fbioe.2015.00036] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2015] [Accepted: 03/04/2015] [Indexed: 01/12/2023] Open
Affiliation(s)
| | | | | | | | - Tanai Cardona
- Department of Life Sciences, Imperial College London , London , UK
| | - Andrea Fantuzzi
- Department of Life Sciences, Imperial College London , London , UK
| | | | - James W Murray
- Department of Life Sciences, Imperial College London , London , UK
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Airs R, Temperton B, Sambles C, Farnham G, Skill S, Llewellyn C. Chlorophyllfand chlorophylldare produced in the cyanobacteriumChlorogloeopsis fritschiiwhen cultured under natural light and near-infrared radiation. FEBS Lett 2014; 588:3770-7. [DOI: 10.1016/j.febslet.2014.08.026] [Citation(s) in RCA: 74] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2014] [Revised: 08/20/2014] [Accepted: 08/20/2014] [Indexed: 11/26/2022]
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20
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Hou X, Raposo A, Hou HJM. Response of chlorophyll d-containing cyanobacterium Acaryochloris marina to UV and visible irradiations. PHOTOSYNTHESIS RESEARCH 2013; 117:497-507. [PMID: 24158260 DOI: 10.1007/s11120-013-9946-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/07/2013] [Accepted: 10/09/2013] [Indexed: 05/03/2023]
Abstract
We have previously investigated the response mechanisms of photosystem II complexes from spinach to strong UV and visible irradiations (Wei et al J Photochem Photobiol B 104:118-125, 2011). In this work, we extend our study to the effects of strong light on the unusual cyanobacterium Acaryochloris marina, which is able to use chlorophyll d (Chl d) to harvest solar energy at a longer wavelength (740 nm). We found that ultraviolet (UV) or high level of visible and near-far red light is harmful to A. marina. Treatment with strong white light (1,200 μmol quanta m(-2) s(-1)) caused a parallel decrease in PSII oxygen evolution of intact cells and in extracted pigments Chl d, zeaxanthin, and α-carotene analyzed by high-performance liquid chromatography, with severe loss after 6 h. When cells were irradiated with 700 nm of light (100 μmol quanta m(-2) s(-1)) there was also bleaching of Chl d and loss of photosynthetic activity. Interestingly, UVB radiation (138 μmol quanta m(-2) s(-1)) caused a loss of photosynthetic activity without reduction in Chl d. Excess absorption of light by Chl d (visible or 700 nm) causes a reduction in photosynthesis and loss of pigments in light harvesting and photoprotection, likely by photoinhibition and inactivation of photosystem II, while inhibition of photosynthesis by UVB radiation may occur by release of Mn ion(s) in Mn4CaO5 center in photosystem II.
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Affiliation(s)
- Xuejing Hou
- Department of Chemistry and Biochemistry, University of Massachusetts Dartmouth, 285 Old Westport Road, North Dartmouth, MA, 02747, USA
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21
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Mauzerall D. Thermodynamics of primary photosynthesis. PHOTOSYNTHESIS RESEARCH 2013; 116:363-366. [PMID: 24037682 PMCID: PMC3825034 DOI: 10.1007/s11120-013-9919-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/03/2013] [Accepted: 08/27/2013] [Indexed: 06/02/2023]
Abstract
The thermodynamics of photosynthesis has been much discussed, but recent articles have pointed to some confusion on the subject. The aim of this review is to clarify a limited part of this state of affairs.
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Affiliation(s)
- D Mauzerall
- Rockefeller University, 1230 York Ave, New York, NY, 10065, USA,
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Loughlin P, Lin Y, Chen M. Chlorophyll d and Acaryochloris marina: current status. PHOTOSYNTHESIS RESEARCH 2013; 116:277-93. [PMID: 23615924 DOI: 10.1007/s11120-013-9829-y] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2013] [Accepted: 04/14/2013] [Indexed: 05/03/2023]
Abstract
The discovery of the chlorophyll d-containing cyanobacterium Acaryochloris marina in 1996 precipitated a shift in our understanding of oxygenic photosynthesis. The presence of the red-shifted chlorophyll d in the reaction centre of the photosystems of Acaryochloris has opened up new avenues of research on photosystem energetics and challenged the unique status of chlorophyll a in oxygenic photosynthesis. In this review, we detail the chemistry and role of chlorophyll d in photosynthesis and summarise the unique adaptations that have allowed the proliferation of Acaryochloris in diverse ecological niches around the world.
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Affiliation(s)
- Patrick Loughlin
- School of Biological Sciences (A08), University of Sydney, Sydney, NSW, 2006, Australia
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23
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Chisti Y. Constraints to commercialization of algal fuels. J Biotechnol 2013; 167:201-14. [DOI: 10.1016/j.jbiotec.2013.07.020] [Citation(s) in RCA: 510] [Impact Index Per Article: 46.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2013] [Revised: 07/12/2013] [Accepted: 07/12/2013] [Indexed: 01/01/2023]
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Photosystem trap energies and spectrally-dependent energy-storage efficiencies in the Chl d-utilizing cyanobacterium, Acaryochloris marina. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2013; 1827:255-65. [DOI: 10.1016/j.bbabio.2012.11.002] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/25/2012] [Revised: 10/08/2012] [Accepted: 11/02/2012] [Indexed: 12/27/2022]
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25
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Larkum AWD, Chen M, Li Y, Schliep M, Trampe E, West J, Salih A, Kühl M. A Novel Epiphytic Chlorophyll d-containing Cyanobacterium Isolated from a Mangrove-associated Red Alga. JOURNAL OF PHYCOLOGY 2012; 48:1320-1327. [PMID: 27009985 DOI: 10.1111/j.1529-8817.2012.01233.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/11/2011] [Accepted: 05/05/2012] [Indexed: 06/05/2023]
Abstract
A new habitat and a new chlorophyll (Chl) d-containing cyanobacterium belonging to the genus Acaryochloris are reported in this study. Hyperspectral microscopy showed the presence of Chl d-containing microorganisms in epiphytic biofilms on a red alga (Gelidium caulacantheum) colonizing the pneumato-phores of a temperate mangrove (Avicennia marina). The presence of Chl d was further proven by high performance liquid chromatography (HPLC)-based pigment analysis and by confocal imaging of cultured cells. Enrichment of mangrove biofilm samples under near-infrared radiation (NIR) yielded the new Acaryochloris sp. MPGRS1, which was closely related in terms of 16S rRNA gene sequence to an isolate from the hypertrophic Salton Sea, USA. The new isolate used Chl d as its major photopigment; Chl d and Chl a contents were ~98% and 1%-2% of total cellular chlorophyll, respectively. These findings expand the variety of ecological niches known to harbor Chl d-containing cyanobacteria and support our working hypothesis that such oxyphototrophs may be ubiquitous in habitats depleted of visible light, but with sufficient NIR exposure.
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Affiliation(s)
- Anthony W D Larkum
- School of Biological Sciences (A08), University of Sydney, Sydney, NSW, 2006, Australia
| | - Min Chen
- School of Biological Sciences (A08), University of Sydney, Sydney, NSW, 2006, Australia
| | - Yaqiong Li
- School of Biological Sciences (A08), University of Sydney, Sydney, NSW, 2006, Australia
| | - Martin Schliep
- School of Biological Sciences (A08), University of Sydney, Sydney, NSW, 2006, Australia
| | - Erik Trampe
- Marine Biological Section, Department of Biology, University of Copenhagen, Strandpromenaden 5, Helsingør, DK-3000, Denmark
| | - John West
- School of Botany, University of Melbourne, Parkville, Victoria, 3024, Australia
| | - Anya Salih
- Confocal Bio-Imaging Facility, School of Science and Health, University of Western Sydney, Richmond, NSW, 2753, Australia
| | - Michael Kühl
- Marine Biological Section, Department of Biology, University of Copenhagen, Strandpromenaden 5, Helsingør, DK-3000, Denmark
- Plant Functional Biology and Climate Change Cluster, University of Technology Sydney, Ultimo, NSW, 2007, Australia
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26
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Hasan SS, Cramer WA. On rate limitations of electron transfer in the photosynthetic cytochrome b6f complex. Phys Chem Chem Phys 2012; 14:13853-60. [PMID: 22890107 DOI: 10.1039/c2cp41386h] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Considering information in the crystal structures of the cytochrome b(6)f complex relevant to the rate-limiting step in oxygenic photosynthesis, it is enigmatic that electron transport in the complex is not limited by the large distance, approximately 26 Å, between the iron-sulfur cluster (ISP) and its electron acceptor, cytochrome f. This enigma has been explained for the respiratory bc(1) complex by a crystal structure with a greatly shortened cluster-heme c(1) distance, leading to a concept of ISP dynamics in which the ISP soluble domain undergoes a translation-rotation conformation change and oscillates between positions relatively close to the cyt c(1) heme and a membrane-proximal position close to the ubiquinol electron-proton donor. Comparison of cytochrome b(6)f structures shows a variation in cytochrome f heme position that suggests the possibility of flexibility and motion of the extended cytochrome f structure that could entail a transient decrease in cluster-heme f distance. The dependence of cyt f turnover on lumen viscosity is consistent with a role of ISP - cyt f dynamics in determination of the rate-limiting step under conditions of low light intensity. Under conditions of low light intensity and proton electrochemical gradient present, for example, under a leaf canopy, it is proposed that a rate limitation of electron transport in the b(6)f complex may also arise from steric constraints in the entry/exit portal for passage of the plastoquinol and -quinone to/from its oxidation site proximal to the iron-sulfur cluster.
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Affiliation(s)
- S Saif Hasan
- Department of Biological Sciences, Hockmeyer Hall of Structural Biology, Purdue University, West Lafayette, IN 47907, USA
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Chen M, Li Y, Birch D, Willows RD. A cyanobacterium that contains chlorophyll f--a red-absorbing photopigment. FEBS Lett 2012; 586:3249-54. [PMID: 22796191 DOI: 10.1016/j.febslet.2012.06.045] [Citation(s) in RCA: 93] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2012] [Revised: 06/24/2012] [Accepted: 06/25/2012] [Indexed: 12/20/2022]
Abstract
A Chl f-containing filamentous cyanobacterium was purified from stromatolites and named as Halomicronema hongdechloris gen., sp. nov. after its phylogenetic classification and the morphological characteristics. Hongdechloris contains four main carotenoids and two chlorophylls, a and f. The ratio of Chl f to Chl a is reversibly changed from 1:8 under red light to an undetectable level of Chl f under white-light culture conditions. Phycobiliproteins were induced under white light growth conditions. A fluorescence emission peak of 748 nm was identified as due to Chl f. The results suggest that Chl f is a red-light inducible chlorophyll.
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Affiliation(s)
- Min Chen
- School of Biological Sciences (A08), University of Sydney, NSW 2006, Australia.
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28
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Hou X, Hou HJM. Roles of manganese in photosystem II dynamics to irradiations and temperatures. ACTA ACUST UNITED AC 2012. [DOI: 10.1007/s11515-012-1214-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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29
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Biofilm growth and near-infrared radiation-driven photosynthesis of the chlorophyll d-containing cyanobacterium Acaryochloris marina. Appl Environ Microbiol 2012; 78:3896-904. [PMID: 22467501 DOI: 10.1128/aem.00397-12] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The cyanobacterium Acaryochloris marina is the only known phototroph harboring chlorophyll (Chl) d. It is easy to cultivate it in a planktonic growth mode, and A. marina cultures have been subject to detailed biochemical and biophysical characterization. In natural situations, A. marina is mainly found associated with surfaces, but this growth mode has not been studied yet. Here, we show that the A. marina type strain MBIC11017 inoculated into alginate beads forms dense biofilm-like cell clusters, as in natural A. marina biofilms, characterized by strong O(2) concentration gradients that change with irradiance. Biofilm growth under both visible radiation (VIS, 400 to 700 nm) and near-infrared radiation (NIR, ∼700 to 730 nm) yielded maximal cell-specific growth rates of 0.38 per day and 0.64 per day, respectively. The population doubling times were 1.09 and 1.82 days for NIR and visible light, respectively. The photosynthesis versus irradiance curves showed saturation at a photon irradiance of E(k) (saturating irradiance) >250 μmol photons m(-2) s(-1) for blue light but no clear saturation at 365 μmol photons m(-2) s(-1) for NIR. The maximal gross photosynthesis rates in the aggregates were ∼1,272 μmol O(2) mg Chl d(-1) h(-1) (NIR) and ∼1,128 μmol O(2) mg Chl d(-1) h(-1) (VIS). The photosynthetic efficiency (α) values were higher in NIR-irradiated cells [(268 ± 0.29) × 10(-6) m(2) mg Chl d(-1) (mean ± standard deviation)] than under blue light [(231 ± 0.22) × 10(-6) m(2) mg Chl d(-1)]. A. marina is well adapted to a biofilm growth mode under both visible and NIR irradiance and under O(2) conditions ranging from anoxia to hyperoxia, explaining its presence in natural niches with similar environmental conditions.
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