Could photosynthesis function on Proxima Centauri b?

2017 ◽  
Vol 17 (2) ◽  
pp. 147-176 ◽  
Author(s):  
Raymond J. Ritchie ◽  
Anthony W.D. Larkum ◽  
Ignasi Ribas
Keyword(s):  
Photosynthetic Bacteria ◽  
Rhodopseudomonas Palustris ◽  
Oxygenic Photosynthesis ◽  
Anoxygenic Photosynthesis ◽  
Gross Photosynthesis ◽  
Light Regimes ◽  
Photosynthetic Organisms ◽  
Near Ir ◽  
Acaryochloris Marina ◽  
Blastochloris Viridis

AbstractCould oxygenic and/or anoxygenic photosynthesis exist on planet Proxima Centauri b? Proxima Centauri (spectral type – M5.5 V, 3050 K) is a red dwarf, whereas the Sun is type G2 V (5780 K). The light regimes on Earth and Proxima Centauri b are compared with estimates of the planet's suitability for Chlorophylla(Chla) and Chld-based oxygenic photosynthesis and for bacteriochlorophyll (BChl)-based anoxygenic photosynthesis. Proxima Centauri b has low irradiance in the oxygenic photosynthesis range (400–749 nm: 64–132 µmol quanta m−2s−1). Much larger amounts of light would be available for BChl-based anoxygenic photosynthesis (350–1100 nm: 724–1538 µmol quanta m−2s−1). We estimated primary production under these light regimes. We used the oxygenic algaeSynechocystisPCC6803,Prochlorothrix hollandica,Acaryochloris marina,Chlorella vulgaris,Rhodomonassp. andPhaeodactylum tricornutumand the anoxygenic photosynthetic bacteriaRhodopseudomonas palustris(BChla),Afifella marina(BChla),Thermochromatium tepidum(BChla),Chlorobaculum tepidum(BChla + c) andBlastochloris viridis(BChlb) as representative photosynthetic organisms. Proxima Centauri b has only ≈3% of the PAR (400–700 nm) of Earth irradiance, but we found that potential gross photosynthesis (Pg) on Proxima Centauri b could be surprisingly high (oxygenic photosynthesis: earth ≈0.8 gC m−2h−1; Proxima Centauri b ≈0.14 gC m−2h−1). The proportion of PAR irradiance useable by oxygenic photosynthetic organisms (the sum of Blue + Red irradiance) is similar for the Earth and Proxima Centauri b. The oxygenic photic zone would be only ≈10 m deep in water compared with ≈200 m on Earth. ThePgof an anoxic Earth (gC m−2h−1) is ≈0.34–0.59 (land) and could be as high as ≈0.29–0.44 on Proxima Centauri b. 1 m of water does not affect oxygenic or anoxygenic photosynthesis on Earth, but on Proxima Centauri b oxygenicPgis reduced by ≈50%. Effective elimination of near IR limitsPgby photosynthetic bacteria (<10% of the surface value). The spectrum of Proxima Centauri b is unfavourable for anoxygenic aquatic photosynthesis. Nevertheless, a substantial aerobic or anaerobic ecology is possible on Proxima Centauri b. Protocols to recognize the biogenic signature of anoxygenic photosynthesis are needed.

scholarly journals Brief review of phototrophs in the Crimean hypersaline lakesand lagoons: diversity, ecological role, the possibility of using

2017 ◽  
Vol 2 (2) ◽  
pp. 80-85 ◽  
Author(s):  
N. V. Shadrin ◽  
E. V. Anufriieva ◽  
S. N. Shadrina
Keyword(s):  
Secondary Metabolites ◽  
Oxygenic Photosynthesis ◽  
Green Bacteria ◽  
Ecological Role ◽  
Anoxygenic Photosynthesis ◽  
Adaptive Mechanisms ◽  
Different Types ◽  
Extreme Habitats

Widespread, including in Crimea, hypersaline waters are among the most extreme habitats of the planet. The need to adapt organisms to living in polyextreme environment has led to the development of a variety of adaptive mechanisms with a synthesis of unique secondary metabolites, which makes organisms dwelling hypersaline waters very promising to use them in different areas of biotechnology and aquaculture. There are three groups of phototrophs using different types of phototrophy in the Crimean hypersaline waters: oxygenic photosynthesis (cyanobacteria, microalgae, and plants), anoxygenic photosynthesis (purple and green bacteria) and proton bacteriorhodopsin pump (archaea). Diversity and roles of these groups in the Crimean lakes and lagoons as well as some perspectives of their practical use are discussed.

scholarly journals The effects of Rhodopseudomonas palustris PSB06 and CGA009 with different agricultural applications on rice growth and rhizosphere bacterial communities

AMB Express ◽  
2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Luyun Luo ◽  
Pei Wang ◽  
Zhongying Zhai ◽  
Pin Su ◽  
Xinqiu Tan ◽  
...  
Keyword(s):  
Treatment Group ◽  
Bacterial Communities ◽  
Photosynthetic Bacteria ◽  
Rhodopseudomonas Palustris ◽  
Rice Seedling ◽  
Seedling Stage ◽  
Rice Rhizosphere ◽  
Rice Growth ◽  
Agricultural Applications ◽  
Rhizosphere Bacterial Communities

Abstract In recent years, the photosynthetic bacteria have been used widely in agriculture, but the effects of different agricultural applications on crop rhizosphere microorganism and crops are lack. In this study, we provide new insights into the structure and composition of the rice root-associated microbiomes as well as the effect on crop of the Rhodopseudomonas palustris(R. palustris) PSB06 and CGA009 at the rice seedling stage with seed immersion and root irrigation. Compare with CK group, the length of stem, the peroxidase (POD), and superoxide dismutase (SOD) activities in PSB06 treatment group was significantly higher, while the length of stem in CGA009 treatment group was significantly higher. The POD and SOD activities in CGA009 treatment groups only were higher slightly than the CK group. In the study, the dominant phyla were Proteobacteria (51.95–61.66%), Bacteroidetes (5.40–9.39%), Acidobacteria (4.50–10.52%), Actinobacteria (5.06–8.14%), Planctomycetes (2.90–4.48%), Chloroflexi (2.23–5.06%) and Firmicutes (2.38–7.30%), accounted for 87% bacterial sequences. The principal coordinate analysis (pCoA) and mantel results showed the two application actions of R. palustris CGA009 and PSB06 had significant effects on rice rhizosphere bacterial communities (p < 0.05). The PSB06 can significantly promote the rice growth and enhance stress resistance of rice at the seedling stage, while the R. palustris CGA009 has no significant effect on rice. Dissimilarity test and canonical correspondence analysis (CCA) results showed that the TN and pH were the key factors affecting rice rhizosphere bacterial community in the seedling stage. This study will provide some guidance advices for the study of the microecological regulation of photosynthetic bacteria on crops.

scholarly journals Lysine Propionylation is a Widespread Post-Translational Modification Involved in Regulation of Photosynthesis and Metabolism in Cyanobacteria

2019 ◽  
Vol 20 (19) ◽  
pp. 4792 ◽  
Author(s):  
Mingkun Yang ◽  
Hui Huang ◽  
Feng Ge
Keyword(s):  
Large Fraction ◽  
Bioinformatic Analysis ◽  
High Light ◽  
Site Directed Mutagenesis ◽  
Oxygenic Photosynthesis ◽  
Post Translational Modification ◽  
Functional Studies ◽  
Photosynthetic Organisms ◽  
Model Combining ◽  
And Function

Lysine propionylation is a reversible and widely distributed post-translational modification that is known to play a regulatory role in both eukaryotes and prokaryotes. However, the extent and function of lysine propionylation in photosynthetic organisms remains unclear. Cyanobacteria are the most ancient group of Gram-negative bacteria capable of oxygenic photosynthesis, and are of great importance to global carbon and nitrogen cycles. Here, we carried out a systematic study of lysine propionylaiton in cyanobacteria where we used Synechocystis sp. PCC 6803 (Synechocystis) as a model. Combining high-affinity anti-propionyllysine pan antibodies with high-accuracy mass spectrometry (MS) analysis, we identified 111 unique lysine propionylation sites on 69 proteins in Synechocystis. Further bioinformatic analysis showed that a large fraction of the propionylated proteins were involved in photosynthesis and metabolism. The functional significance of lysine propionylation on the enzymatic activity of fructose-1,6-bisphosphatase (FbpI) was studied by site-directed mutagenesis and biochemical studies. Further functional studies revealed that the propionylation level of subunit II of photosystem I (PsaD) was obviously increased after high light (HL) treatment, suggesting that propionylation may be involved in high light adaption in Synechocystis. Thus, our findings provide novel insights into the range of functions regulated by propionylation and reveal that reversible propionylation is a functional modification with the potential to regulate photosynthesis and carbon metabolism in Synechocystis, as well as in other photosynthetic organisms.

scholarly journals Evolutionary ecology during the rise of dioxygen in the Earth's atmosphere

2008 ◽  
Vol 363 (1504) ◽  
pp. 2651-2664 ◽  
Author(s):  
Norman H Sleep ◽  
Dennis K Bird
Keyword(s):  
Ferrous Iron ◽  
Evolutionary Ecology ◽  
Granitic Rocks ◽  
Oxygenic Photosynthesis ◽  
Ridge Axis ◽  
Anoxygenic Photosynthesis ◽  
Arc Volcanism ◽  
Oxidized Iron ◽  
Mid Ocean Ridge ◽  
Ocean Ridge

Pre-photosynthetic niches were meagre with a productivity of much less than 10 −4 of modern photosynthesis. Serpentinization, arc volcanism and ridge-axis volcanism reliably provided H 2 . Methanogens and acetogens reacted CO 2 with H 2 to obtain energy and make organic matter. These skills pre-adapted a bacterium for anoxygenic photosynthesis, probably starting with H 2 in lieu of an oxygen ‘acceptor’. Use of ferrous iron and sulphide followed as abundant oxygen acceptors, allowing productivity to approach modern levels. The ‘photobacterium’ proliferated rooting much of the bacterial tree. Land photosynthetic microbes faced a dearth of oxygen acceptors and nutrients. A consortium of photosynthetic and soil bacteria aided weathering and access to ferrous iron. Biologically enhanced weathering led to the formation of shales and, ultimately, to granitic rocks. Already oxidized iron-poor sedimentary rocks and low-iron granites provided scant oxygen acceptors, as did freshwater in their drainages. Cyanobacteria evolved dioxygen production that relieved them of these vicissitudes. They did not immediately dominate the planet. Eventually, anoxygenic and oxygenic photosynthesis oxidized much of the Earth's crust and supplied sulphate to the ocean. Anoxygenic photosynthesis remained important until there was enough O 2 in downwelling seawater to quantitatively oxidize massive sulphides at mid-ocean ridge axes.

scholarly journals Photosynthetic apparatus of purple bacteria

2002 ◽  
Vol 35 (1) ◽  
pp. 1-62 ◽  
Author(s):  
Xiche Hu ◽  
Thorsten Ritz ◽  
Ana Damjanović ◽  
Felix Autenrieth ◽  
Klaus Schulten
Keyword(s):  
Photosynthetic Bacteria ◽  
Higher Plants ◽  
Purple Bacteria ◽  
Photosynthetic Apparatus ◽  
Excitation Transfer ◽  
Oxygenic Photosynthesis ◽  
Photosynthetic Reaction Centers ◽  
Primary Charge Separation ◽  
Photosynthetic Membrane ◽  
Light Harvesting Complexes

1. Introduction 22. Structure of the bacterial PSU 52.1 Organization of the bacterial PSU 52.2 The crystal structure of the RC 92.3 The crystal structures of LH-II 112.4 Bacteriochlorophyll pairs in LH-II and the RC 132.5 Models of LH-I and the LH-I-RC complex 152.6 Model for the PSU 173. Excitation transfer in the PSU 183.1 Electronic excitations of BChls 22 3.1.1 Individual BChls 22 3.1.2 Rings of BChls 22 3.1.2.1 Exciton states 22 3.1.3 Effective Hamiltonian 24 3.1.4 Optical properties 25 3.1.5 The effect of disorder 263.2 Theory of excitation transfer 29 3.2.1 General theory 29 3.2.2 Mechanisms of excitation transfer 32 3.2.3 Approximation for long-range transfer 34 3.2.4 Transfer to exciton states 353.3 Rates for transfer processes in the PSU 37 3.3.1 Car→BChl transfer 37 3.3.1.1 Mechanism of Car→BChl transfer 39 3.3.1.2 Pathways of Car→BChl transfer 40 3.3.2 Efficiency of Car→BChl transfer 40 3.3.3 B800-B850 transfer 44 3.3.4 LH-II→LH-II transfer 44 3.3.5 LH-II→LH-I transfer 45 3.3.6 LH-I→RC transfer 45 3.3.7 Excitation migration in the PSU 46 3.3.8 Genetic basis of PSU assembly 494. Concluding remarks 535. Acknowledgments 556. References 55Life as we know it today exists largely because of photosynthesis, the process through which light energy is converted into chemical energy by plants, algae, and photosynthetic bacteria (Priestley, 1772; Barnes, 1893; Wurmser, 1925; Van Niel, 1941; Clayton & Sistrom, 1978; Blankenship et al. 1995; Ort & Yocum, 1996). Historically, photosynthetic organisms are grouped into two classes. When photosynthesis is carried out in the presence of air it is called oxygenic photosynthesis (Ort & Yocum, 1996). Otherwise, it is anoxygenic (Blankenship et al. 1995). Higher plants, algae and cyanobacteria perform oxygenic photosynthesis, which involves reduction of carbon dioxide to carbohydrate and oxidation of water to produce molecular oxygen. Some photosynthetic bacteria, such as purple bacteria, carry out anoxygenic photosynthesis that involves oxidation of molecules other than water. In spite of these differences, the general principles of energy transduction are the same in anoxygenic and oxygenic photosynthesis (Van Niel, 1931, 1941; Stanier, 1961; Wraight, 1982; Gest, 1993). The primary processes of photosynthesis involve absorption of photons by light-harvesting complexes (LHs), transfer of excitation energy from LHs to the photosynthetic reaction centers (RCs), and the primary charge separation across the photosynthetic membrane (Sauer, 1975; Knox, 1977; Fleming & van Grondelle, 1994; van Grondelle et al. 1994). In this article, we will focus on the anoxygenic photosynthetic process in purple bacteria, since its photosynthetic system is the most studied and best characterized during the past 50 years.

scholarly journals Type II photosynthetic reaction center genes of avocado (Persea americana Mill.) bark microbial communities are dominated by aerobic anoxygenic Alphaproteobacteria

2020 ◽  
Author(s):  
Eneas Aguirre-von-Wobeser
Keyword(s):  
Microbial Communities ◽  
Reaction Center ◽  
Photosynthetic Reaction Center ◽  
Persea Americana ◽  
Algorithm Analysis ◽  
Tree Bark ◽  
Oxygenic Photosynthesis ◽  
Type Ii ◽  
Additional Energy ◽  
Anoxygenic Photosynthesis

AbstractThe tree bark environment is an important microbial habitat distributed worldwide on thrillions of trees. However, the microbial communities of tree bark are largely unknown, with most studies on plant aerial surfaces focused on the leaves. Recently, we presented a metagenomic study of bark microbial communities from avocado. In these communities, oxygenic and anoxygenic photosynthesis genes were very abundant, especially when compared to rhizospheric soil from the same trees. In this work, Evolutionary Placement Algorithm analysis was performed on metagenomic reads orthologous to the PufLM gene cluster, encoding for the bacterial type II photosynthetic reaction center. These photosynthetic genes were found affiliated to different groups of bacteria, mostly aerobic anoxygenic photosynthetic Alphaproteobacteria, including Sphingomonas, Methylobacterium and several Rhodospirillales. These results suggest that anoxygenic photosynthesis in avocado bark microbial communities functions primarily as additional energy source for heterotrophic growth. Together with our previous results, showing a large abundance of cyanobacteria in these communities, a picture emerges of the tree holobiont, where light penetrating the trees canopies and reaching the inner stems, including the trunk, is probably utilized by cyanobacteria for oxygenic photosynthesis, and the far-red light aids the growth of aerobic anoxygenic photosynthetic bacteria.

scholarly journals Regulation of electron transport is essential for photosystem I stability and plant growth

2019 ◽  
Author(s):  
Mattia Storti ◽  
Anna Segalla ◽  
Marco Mellon ◽  
Alessandro Alboresi ◽  
Tomas Morosinotto
Keyword(s):  
Electron Transport ◽  
Photosystem I ◽  
Nadh Dehydrogenase ◽  
Physcomitrella Patens ◽  
Electron Flow ◽  
Photosynthetic Electron Transport ◽  
Type I ◽  
Growth Reduction ◽  
Light Regimes ◽  
Photosynthetic Organisms

AbstractLife depends on the ability of photosynthetic organisms to exploit sunlight to fix carbon dioxide into biomass. Photosynthesis is modulated by pathways such as cyclic and pseudocyclic electron flow (CEF and PCEF). CEF transfers electrons from photosystem I to the plastoquinone pool according to two mechanisms, one dependent on proton gradient regulators (PGR5/PGRL1) and the other on the type I NADH dehydrogenase (NDH) complex. PCEF uses electrons from photosystem I to reduce oxygen; in several groups of photosynthetic organisms but not in angiosperms, it is sustained by flavodiiron proteins (FLVs). PGR5/PGRL1, NDH and FLVs are all active in the moss Physcomitrella patens, and mutants depleted in these proteins show phenotypes under specific light regimes. Here, we demonstrated that CEF and PCEF exhibit strong functional overlap and that when one protein component is depleted, the others can compensate for most of the missing activity. When multiple mechanisms are simultaneously inactivated, however, plants show damage to photosystem I and strong growth reduction, demonstrating that mechanisms for the modulation of photosynthetic electron transport are indispensable.

scholarly journals Photosynthetic performance in cyanobacteria with increased sulphide tolerance: an analysis comparing wild-type and experimentally derived strains

2021 ◽  
Author(s):  
Elena Martín-Clemente ◽  
Ignacio J. Melero-Jiménez ◽  
Elena Bañares-España ◽  
Antonio Flores-Moya ◽  
María J. García-Sánchez
Keyword(s):  
Resistance Mechanisms ◽  
Photosynthetic Performance ◽  
Oxygenic Photosynthesis ◽  
Wild Type ◽  
Sensitive Species ◽  
Anoxygenic Photosynthesis ◽  
In The Wild ◽  
Photosynthetic Machinery ◽  
Type Strains ◽  
Shed Light

AbstractSulphide is proposed to have influenced the evolution of primary stages of oxygenic photosynthesis in cyanobacteria. However, sulphide is toxic to most of the species of this phylum, except for some sulphide-tolerant species showing various sulphide-resistance mechanisms. In a previous study, we found that this tolerance can be induced by environmental sulphidic conditions, in which two experimentally derived strains with an enhanced tolerance to sulphide were obtained from Microcystis aeruginosa, a sensitive species, and Oscillatoria, a sulphide-tolerant genus. We have now analysed the photosynthetic performance of the wild-type and derived strains in the presence of sulphide to shed light on the characteristics underlying the increased tolerance. We checked whether the sulphide tolerance was a result of higher PSII sulphide resistance and/or the induction of sulphide-dependent anoxygenic photosynthesis. We observed that growth, maximum quantum yield, maximum electron transport rate and photosynthetic efficiency in the presence of sulphide were less affected in the derived strains compared to their wild-type counterparts. Nevertheless, in 14C photoincoporation assays, neither Oscillatoria nor M. aeruginosa exhibited anoxygenic photosynthesis using sulphide as an electron donor. On the other hand, the content of photosynthetic pigments in the derived strains was different to that observed in the wild-type strains. Thus, an enhanced PSII sulphide resistance appears to be behind the increased sulphide tolerance displayed by the experimentally derived strains, as observed in most natural sulphide-tolerant cyanobacterial strains. However, other changes in the photosynthetic machinery cannot be excluded.

scholarly journals Looking for life elsewhere: Photosynthesis and astrobiology

2014 ◽  
Vol 36 (6) ◽  
pp. 24-30 ◽  
Author(s):  
Nancy Y. Kiang
Keyword(s):  
Solar System ◽  
Energy Use ◽  
Atmospheric Oxygen ◽  
Oxygenic Photosynthesis ◽  
Spectral Features ◽  
Reaction Centre ◽  
Absorbance Spectrum ◽  
Stellar Spectrum ◽  
Chl A ◽  
Photosynthetic Organisms

Photosynthesis produces signs of life we can see from space: the absorbance spectrum of surface photosynthetic pigments and, with oxygenic photosynthesis, atmospheric oxygen. Since the first discovery of a planet in another solar system in 1989, there has been an explosion in the detection of exoplanets (over 1849 as of 7 November 2014) and we are getting ever closer to finding that Goldilocks planet that might harbour life. With telescope observations of these planets, oxygenic photosynthesis has been considered our most robust target ‘biosignature’ that would not appear on a lifeless planet. Since anoxygenic photosynthetic organisms do not produce unambiguously biogenic gases, there is interest in their pigments serving as spectral indicators of life. But will they look the same as on Earth, can we distinguish them from the abiotic, and what will dominate on another planet? Examples from Earth provide us with the potential to extrapolate some rules for photosynthesis to predict its signature on another planet, but there are yet things we must answer about life here to improve our confidence. In particular, given the combination of the available stellar spectrum and molecular constraints on photon energy use, can we predict the pigment spectral features that will dominate, which reductant will match, and what biogenic gases would result? We take clues from the diversity of anoxygenic photosynthetic metabolisms and three very recent examples of oxygenic photosynthesis utilizing other reaction centre (RC) chlorophylls in addition to chlorophyll a (Chl a).

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