scholarly journals Interplay between differentially expressed enzymes contributes to light color acclimation in marineSynechococcus

2019 ◽  
Vol 116 (13) ◽  
pp. 6457-6462 ◽  
Author(s):  
Joseph E. Sanfilippo ◽  
Adam A. Nguyen ◽  
Laurence Garczarek ◽  
Jonathan A. Karty ◽  
Suman Pokhrel ◽  
...  
Keyword(s):  
Blue Light ◽  
Light Harvesting ◽  
Green Light ◽  
Cysteine Residue ◽  
Covalent Attachment ◽  
Critical Feature ◽  
Light Harvesting Complexes ◽  
Important Group ◽  
Chromatic Acclimation ◽  
Light Color

MarineSynechococcus, a globally important group of cyanobacteria, thrives in various light niches in part due to its varied photosynthetic light-harvesting pigments. ManySynechococcusstrains use a process known as chromatic acclimation to optimize the ratio of two chromophores, green-light–absorbing phycoerythrobilin (PEB) and blue-light–absorbing phycourobilin (PUB), within their light-harvesting complexes. A full mechanistic understanding of howSynechococcuscells tune their PEB to PUB ratio during chromatic acclimation has not yet been obtained. Here, we show that interplay between two enzymes named MpeY and MpeZ controls differential PEB and PUB covalent attachment to the same cysteine residue. MpeY attaches PEB to the light-harvesting protein MpeA in green light, while MpeZ attaches PUB to MpeA in blue light. We demonstrate that the ratio ofmpeYtompeZmRNA determines if PEB or PUB is attached. Additionally, strains encoding only MpeY or MpeZ do not acclimate. Examination of strains ofSynechococcusisolated from across the globe indicates that the interplay between MpeY and MpeZ uncovered here is a critical feature of chromatic acclimation for marineSynechococcusworldwide.

scholarly journals Two Cyanobacterial Photoreceptors Regulate Photosynthetic Light Harvesting by Sensing Teal, Green, Yellow, and Red Light

mBio ◽  
2016 ◽  
Vol 7 (1) ◽  
Author(s):  
Lisa B. Wiltbank ◽  
David M. Kehoe
Keyword(s):  
Absorption Maximum ◽  
Light Harvesting ◽  
Red Light ◽  
Green Light ◽  
Visible Spectrum ◽  
Color Discrimination ◽  
Fremyella Diplosiphon ◽  
Chromatic Acclimation ◽  
Light Color ◽  
Light Harvesting Antenna

ABSTRACT The genomes of many photosynthetic and nonphotosynthetic bacteria encode numerous phytochrome superfamily photoreceptors whose functions and interactions are largely unknown. Cyanobacterial genomes encode particularly large numbers of phytochrome superfamily members called cyanobacteriochromes. These have diverse light color-sensing abilities, and their functions and interactions are just beginning to be understood. One of the best characterized of these functions is the regulation of photosynthetic light-harvesting antenna composition in the cyanobacterium Fremyella diplosiphon by the cyanobacteriochrome RcaE in response to red and green light, a process known as chromatic acclimation. We have identified a new cyanobacteriochrome named DpxA that maximally senses teal (absorption maximum, 494 nm) and yellow (absorption maximum, 568 nm) light and represses the accumulation of a key light-harvesting protein called phycoerythrin, which is also regulated by RcaE during chromatic acclimation. Like RcaE, DpxA is a two-component system kinase, although these two photoreceptors can influence phycoerythrin expression through different signaling pathways. The peak responsiveness of DpxA to teal and yellow light provides highly refined color discrimination in the green spectral region, which provides important wavelengths for photosynthetic light harvesting in cyanobacteria. These results redefine chromatic acclimation in cyanobacteria and demonstrate that cyanobacteriochromes can coordinately impart sophisticated light color sensing across the visible spectrum to regulate important photosynthetic acclimation processes. IMPORTANCE The large number of cyanobacteriochrome photoreceptors encoded by cyanobacterial genomes suggests that these organisms are capable of extremely complex light color sensing and responsiveness, yet little is known about their functions and interactions. Our work uncovers previously undescribed cooperation between two photoreceptors with very different light color-sensing capabilities that coregulate an important photosynthetic light-harvesting protein in response to teal, green, yellow, and red light. Other cyanobacteriochromes that have been shown to interact functionally sense wavelengths of light that are close to each other, which makes it difficult to clearly identify their physiological roles in the cell. Our finding of two photoreceptors with broad light color-sensing capabilities and clearly defined physiological roles provides new insights into complex light color sensing and its regulation.

scholarly journals Molecular bases of an alternative dual-enzyme system for light color acclimation of marine Synechococcus cyanobacteria

2021 ◽  
Vol 118 (9) ◽  
pp. e2019715118
Author(s):  
Théophile Grébert ◽  
Adam A. Nguyen ◽  
Suman Pokhrel ◽  
Kes Lynn Joseph ◽  
Morgane Ratin ◽  
...  
Keyword(s):  
Blue Light ◽  
Critical Role ◽  
Green Light ◽  
Ecological Niches ◽  
Light Harvesting Complexes ◽  
Α Subunit ◽  
Type Iv ◽  
Light Color ◽  
Relationship Of ◽  
Molecular Bases

Marine Synechococcus cyanobacteria owe their ubiquity in part to the wide pigment diversity of their light-harvesting complexes. In open ocean waters, cells predominantly possess sophisticated antennae with rods composed of phycocyanin and two types of phycoerythrins (PEI and PEII). Some strains are specialized for harvesting either green or blue light, while others can dynamically modify their light absorption spectrum to match the dominant ambient color. This process, called type IV chromatic acclimation (CA4), has been linked to the presence of a small genomic island occurring in two configurations (CA4-A and CA4-B). While the CA4-A process has been partially characterized, the CA4-B process has remained an enigma. Here we characterize the function of two members of the phycobilin lyase E/F clan, MpeW and MpeQ, in Synechococcus sp. strain A15-62 and demonstrate their critical role in CA4-B. While MpeW, encoded in the CA4-B island and up-regulated in green light, attaches the green light-absorbing chromophore phycoerythrobilin to cysteine-83 of the PEII α-subunit in green light, MpeQ binds phycoerythrobilin and isomerizes it into the blue light-absorbing phycourobilin at the same site in blue light, reversing the relationship of MpeZ and MpeY in the CA4-A strain RS9916. Our data thus reveal key molecular differences between the two types of chromatic acclimaters, both highly abundant but occupying distinct complementary ecological niches in the ocean. They also support an evolutionary scenario whereby CA4-B island acquisition allowed former blue light specialists to become chromatic acclimaters, while former green light specialists would have acquired this capacity by gaining a CA4-A island.

scholarly journals The Molecular Mechanisms of Photoactivation of Orange Carotenoid Protein Revealed by Molecular Dynamics

2020 ◽  
Author(s):  
Mattia Bondanza ◽  
Lorenzo Cupellini ◽  
Pietro Faccioli ◽  
Benedetta Mennucci
Keyword(s):  
Structural Changes ◽  
Molecular Mechanisms ◽  
Light Harvesting ◽  
Experimental Studies ◽  
Green Light ◽  
Enhanced Sampling ◽  
Light Harvesting Complexes ◽  
Effective Combination ◽  
Large Conformational Change ◽  
Orange Carotenoid Protein

Light-harvesting in photosynthesis is accompanied by photoprotective processes. In cyanobacteria, the photoprotective role is played by a specialized complex, the Orange Carotenoid Protein which is activated by strong blue-green light. This photoactivation involves a unique series of structural changes which terminate with an opening of the complex into two separated domains, one of which acts as a quencher for the light-harvesting complexes. Many experimental studies have tried to reveal the molecular mechanisms through which the energy absorbed by the carotenoid finally leads to the large conformational change of the complex. Here for the first time, these mechanisms are revealed by simulating at atomistic level the whole dynamics of the complex through an effective combination of enhanced sampling techniques. On the basis of our findings, we can conclude that the carotenoid does not act as a spring that, releasing its internal strain, induces the dissociation, as it was previously proposed but as a "latch" locking together the two domains. The photochemically triggered displacement of the carotenoid breaks this balance, allowing the complex to dissociate. <br>

scholarly journals The Molecular Mechanisms of Photoactivation of Orange Carotenoid Protein Revealed by Molecular Dynamics

2020 ◽  
Author(s):  
Mattia Bondanza ◽  
Lorenzo Cupellini ◽  
Pietro Faccioli ◽  
Benedetta Mennucci
Keyword(s):  
Structural Changes ◽  
Molecular Mechanisms ◽  
Light Harvesting ◽  
Experimental Studies ◽  
Green Light ◽  
Enhanced Sampling ◽  
Light Harvesting Complexes ◽  
Effective Combination ◽  
Large Conformational Change ◽  
Orange Carotenoid Protein

Light-harvesting in photosynthesis is accompanied by photoprotective processes. In cyanobacteria, the photoprotective role is played by a specialized complex, the Orange Carotenoid Protein which is activated by strong blue-green light. This photoactivation involves a unique series of structural changes which terminate with an opening of the complex into two separated domains, one of which acts as a quencher for the light-harvesting complexes. Many experimental studies have tried to reveal the molecular mechanisms through which the energy absorbed by the carotenoid finally leads to the large conformational change of the complex. Here for the first time, these mechanisms are revealed by simulating at atomistic level the whole dynamics of the complex through an effective combination of enhanced sampling techniques. On the basis of our findings, we can conclude that the carotenoid does not act as a spring that, releasing its internal strain, induces the dissociation, as it was previously proposed but as a "latch" locking together the two domains. The photochemically triggered displacement of the carotenoid breaks this balance, allowing the complex to dissociate. <br>

scholarly journals Chromatic Acclimation in Cyanobacteria: A Diverse and Widespread Process for Optimizing Photosynthesis

2019 ◽  
Vol 73 (1) ◽  
pp. 407-433 ◽  
Author(s):  
Joseph E. Sanfilippo ◽  
Laurence Garczarek ◽  
Frédéric Partensky ◽  
David M. Kehoe
Keyword(s):  
Molecular Mechanisms ◽  
Light Harvesting ◽  
Solar Spectrum ◽  
Ambient Light ◽  
Molecular Processes ◽  
Comprehensive Overview ◽  
Chromatic Acclimation ◽  
Sense And Respond ◽  
Light Color

Chromatic acclimation (CA) encompasses a diverse set of molecular processes that involve the ability of cyanobacterial cells to sense ambient light colors and use this information to optimize photosynthetic light harvesting. The six known types of CA, which we propose naming CA1 through CA6, use a range of molecular mechanisms that likely evolved independently in distantly related lineages of the Cyanobacteria phylum. Together, these processes sense and respond to the majority of the photosynthetically relevant solar spectrum, suggesting that CA provides fitness advantages across a broad range of light color niches. The recent discoveries of several new CA types suggest that additional CA systems involving additional light colors and molecular mechanisms will be revealed in coming years. Here we provide a comprehensive overview of the currently known types of CA and summarize the molecular details that underpin CA regulation.

scholarly journals Three cyanobacteriochromes work together to form a light color-sensitive input system for c-di-GMP signaling of cell aggregation

2015 ◽  
Vol 112 (26) ◽  
pp. 8082-8087 ◽  
Author(s):  
Gen Enomoto ◽  
Ni-Ni-Win ◽  
Rei Narikawa ◽  
Masahiko Ikeuchi
Keyword(s):  
Blue Light ◽  
Green Light ◽  
Cell Aggregation ◽  
Ambient Light ◽  
Diguanylate Cyclase ◽  
Signaling Specificity ◽  
Input System ◽  
Aggregation Response ◽  
Large Numbers ◽  
Light Color

Cyanobacteriochromes (CBCRs) are cyanobacterial photoreceptors that have diverse spectral properties and domain compositions. Although large numbers of CBCR genes exist in cyanobacterial genomes, no studies have assessed whether multiple CBCRs work together. We recently showed that the diguanylate cyclase (DGC) activity of the CBCR SesA from Thermosynechococcus elongatus is activated by blue-light irradiation and that, when irradiated, SesA, via its product cyclic dimeric GMP (c-di-GMP), induces aggregation of Thermosynechococcus vulcanus cells at a temperature that is suboptimum for single-cell viability. For this report, we first characterize the photobiochemical properties of two additional CBCRs, SesB and SesC. Blue/teal light-responsive SesB has only c-di-GMP phosphodiesterase (PDE) activity, which is up-regulated by teal light and GTP. Blue/green light-responsive SesC has DGC and PDE activities. Its DGC activity is enhanced by blue light, whereas its PDE activity is enhanced by green light. A ΔsesB mutant cannot suppress cell aggregation under teal-green light. A ΔsesC mutant shows a less sensitive cell-aggregation response to ambient light. ΔsesA/ΔsesB/ΔsesC shows partial cell aggregation, which is accompanied by the loss of color dependency, implying that a nonphotoresponsive DGC(s) producing c-di-GMP can also induce the aggregation. The results suggest that SesB enhances the light color dependency of cell aggregation by degrading c-di-GMP, is particularly effective under teal light, and, therefore, seems to counteract the induction of cell aggregation by SesA. In addition, SesC seems to improve signaling specificity as an auxiliary backup to SesA/SesB activities. The coordinated action of these three CBCRs highlights why so many different CBCRs exist.

scholarly journals Light color acclimation is a key process in the global ocean distribution of Synechococcus cyanobacteria

2018 ◽  
Vol 115 (9) ◽  
pp. E2010-E2019 ◽  
Author(s):  
Théophile Grébert ◽  
Hugo Doré ◽  
Frédéric Partensky ◽  
Gregory K. Farrant ◽  
Emmanuel S. Boss ◽  
...  
Keyword(s):  
Blue Light ◽  
Niche Partitioning ◽  
Green Light ◽  
Environmental Parameters ◽  
Global Ocean ◽  
Marker Genes ◽  
Type Iv ◽  
Complex Interactions ◽  
Wide Range ◽  
Light Color

Marine Synechococcus cyanobacteria are major contributors to global oceanic primary production and exhibit a unique diversity of photosynthetic pigments, allowing them to exploit a wide range of light niches. However, the relationship between pigment content and niche partitioning has remained largely undetermined due to the lack of a single-genetic marker resolving all pigment types (PTs). Here, we developed and employed a robust method based on three distinct marker genes (cpcBA, mpeBA, and mpeW) to estimate the relative abundance of all known Synechococcus PTs from metagenomes. Analysis of the Tara Oceans dataset allowed us to reveal the global distribution of Synechococcus PTs and to define their environmental niches. Green-light specialists (PT 3a) dominated in warm, green equatorial waters, whereas blue-light specialists (PT 3c) were particularly abundant in oligotrophic areas. Type IV chromatic acclimaters (CA4-A/B), which are able to dynamically modify their light absorption properties to maximally absorb green or blue light, were unexpectedly the most abundant PT in our dataset and predominated at depth and high latitudes. We also identified populations in which CA4 might be nonfunctional due to the lack of specific CA4 genes, notably in warm high-nutrient low-chlorophyll areas. Major ecotypes within clades I–IV and CRD1 were preferentially associated with a particular PT, while others exhibited a wide range of PTs. Altogether, this study provides important insights into the ecology of Synechococcus and highlights the complex interactions between vertical phylogeny, pigmentation, and environmental parameters that shape Synechococcus community structure and evolution.

scholarly journals Rangsangan Warna Cahaya terhadap Prosentase Karkas Ayam Kampung Super

2021 ◽  
Vol 4 (1) ◽  
pp. 73-78
Author(s):  
Idrus Umar
Keyword(s):  
Blue Light ◽  
White Light ◽  
Red Light ◽  
Green Light ◽  
Carcass Weight ◽  
Yellow Light ◽  
Average Value ◽  
Randomized Design ◽  
Completely Randomized Design ◽  
Light Color

The purpose of the study was to determine the effect of giving different colors of light on carcass percentage and carcass weight in Kampung Super chickens. The research design used was a completely randomized design (CRD). A total of 80 Kampung Super chickens were used in this study. The research treatments were P1 (white light color), P2 (yellow light color), P3 (green light color), P4 (red light color), P5 (blue light color). The results of the study of the highest carcass presentation were found in the treatment that was given red light with an average value of 62.455%. The highest carcass weight was found in the same treatment, which was given a red light with an average value of 674.75 g/head. The provision of different light colors did not have a significant effect on the carcass percentage and carcass weight of the finisher phase super free-range chicken. 

scholarly journals Artificial complementary chromatic acclimation gene expression system in Escherichia coli

2021 ◽  
Vol 20 (1) ◽  
Author(s):  
Dwi Ariyanti ◽  
Kazunori Ikebukuro ◽  
Koji Sode
Keyword(s):  
Gene Expression ◽  
Escherichia Coli ◽  
Light Exposure ◽  
Expression System ◽  
Red Light ◽  
Green Light ◽  
Light Illumination ◽  
Multiple Gene ◽  
Gene Expression System ◽  
Chromatic Acclimation

Abstract Background The development of multiple gene expression systems, especially those based on the physical signals, such as multiple color light irradiations, is challenging. Complementary chromatic acclimation (CCA), a photoreversible process that facilitates the control of cellular expression using light of different wavelengths in cyanobacteria, is one example. In this study, an artificial CCA systems, inspired by type III CCA light-regulated gene expression, was designed by employing a single photosensor system, the CcaS/CcaR green light gene expression system derived from Synechocystis sp. PCC6803, combined with G-box (the regulator recognized by activated CcaR), the cognate cpcG2 promoter, and the constitutively transcribed promoter, the PtrcΔLacO promoter. Results One G-box was inserted upstream of the cpcG2 promoter and a reporter gene, the rfp gene (green light-induced gene expression), and the other G-box was inserted between the PtrcΔLacO promoter and a reporter gene, the bfp gene (red light-induced gene expression). The Escherichia coli transformants with plasmid-encoded genes were evaluated at the transcriptional and translational levels under red or green light illumination. Under green light illumination, the transcription and translation of the rfp gene were observed, whereas the expression of the bfp gene was repressed. Under red light illumination, the transcription and translation of the bfp gene were observed, whereas the expression of the rfp gene was repressed. During the red and green light exposure cycles at every 6 h, BFP expression increased under red light exposure while RFP expression was repressed, and RFP expression increased under green light exposure while BFP expression was repressed. Conclusion An artificial CCA system was developed to realize a multiple gene expression system, which was regulated by two colors, red and green lights, using a single photosensor system, the CcaS/CcaR system derived from Synechocystis sp. PCC6803, in E. coli. The artificial CCA system functioned repeatedly during red and green light exposure cycles. These results demonstrate the potential application of this CCA gene expression system for the production of multiple metabolites in a variety of microorganisms, such as cyanobacteria.

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