The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
Michael Kuhl - One of the best experts on this subject based on the ideXlab platform.
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substantial Near Infrared Radiation driven photosynthesis of chlorophyll f containing cyanobacteria in a natural habitat
eLife, 2020Co-Authors: Michael Kuhl, Erik Trampe, Maria Mosshammer, Michael Johnson, Anthony W D Larkum, Klaus Koren, Nielsulrik FrigaardAbstract:Far-red absorbing chlorophylls are constitutively present as chlorophyll (Chl) d in the cyanobacterium Acaryochloris marina, or dynamically expressed by synthesis of Chl f, red-shifted phycobiliproteins and minor amounts of Chl d via far-red light photoacclimation in a range of cyanobacteria, which enables them to use Near-Infrared-Radiation (NIR) for oxygenic photosynthesis. While the biochemistry and molecular physiology of Chl f-containing cyanobacteria has been unraveled in culture studies, their ecological significance remains unexplored and no data on their in situ activity exist. With a novel combination of hyperspectral imaging, confocal laser scanning microscopy, and nanoparticle-based O2 imaging, we demonstrate substantial NIR-driven oxygenic photosynthesis by endolithic, Chl f-containing cyanobacteria within natural beachrock biofilms that are widespread on (sub)tropical coastlines. This indicates an important role of NIR-driven oxygenic photosynthesis in primary production of endolithic and other shaded habitats.
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substantial Near Infrared Radiation driven photosynthesis of chlorophyll f containing cyanobacteria in a natural habitat
bioRxiv, 2019Co-Authors: Michael Kuhl, Erik Trampe, Maria Mosshammer, Michael Johnson, Anthony W D Larkum, Klaus KorenAbstract:Abstract Far-red absorbing chlorophylls are constitutively present as Chl d in the cyanobacterium Acaryochloris marina, or dynamically expressed by synthesis of Chl f and red-shifted phycobilins via far-red light photoacclimation in a range of cyanobacteria, which enables them to use Near-Infrared-Radiation (NIR) for oxygenic photosynthesis. While the biochemistry and molecular physiology of Chl f-containing cyanobacteria has been unraveled in culture studies, their ecological significance remains unexplored and no data on their in situ activity exist. With a novel combination of hyperspectral imaging, confocal laser scanning microscopy, and nanoparticle-based O2 imaging, we demonstrate substantial NIR-driven oxygenic photosynthesis by endolithic, Chl f-containing cyanobacteria within natural beachrock biofilms that are widespread on (sub)tropical coastlines. This indicates an important role of NIR-driven oxygenic photosynthesis in primary production of endolithic and other shaded habitats. Impact statement Cyanobacteria with chlorophyll f show substantial Near-Infrared Radiation-driven photosynthesis in intertidal habitats.
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biofilm growth and Near Infrared Radiation driven photosynthesis of the chlorophyll d containing cyanobacterium acaryochloris marina
Applied and Environmental Microbiology, 2012Co-Authors: Lars Behrendt, Michael Kuhl, Anthony W D Larkum, Verena Schrameyer, Klaus Qvortrup, Luisa Lundin, Soren J SorensenAbstract: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 O2 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 Ek(saturating irradiance)>250mol photons m 2 s 1 for blue light but no clear saturation at 365 mol photons m 2 s 1 for NIR. The maximal gross photosynthesis rates in the aggregates were 1,272mol O2mg Chld 1 h 1 (NIR) and1,128mol O2mg Chl d 1 h 1 (VIS). The photosynthetic efficiency () values were higher in NIR-irradiated cells [(268 0.29)10 6 m 2 mg Chld 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 2conditions ranging from anoxia to hyperoxia, explaining its presence in natural niches with similar environmental conditions.
Klaus Koren - One of the best experts on this subject based on the ideXlab platform.
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substantial Near Infrared Radiation driven photosynthesis of chlorophyll f containing cyanobacteria in a natural habitat
eLife, 2020Co-Authors: Michael Kuhl, Erik Trampe, Maria Mosshammer, Michael Johnson, Anthony W D Larkum, Klaus Koren, Nielsulrik FrigaardAbstract:Far-red absorbing chlorophylls are constitutively present as chlorophyll (Chl) d in the cyanobacterium Acaryochloris marina, or dynamically expressed by synthesis of Chl f, red-shifted phycobiliproteins and minor amounts of Chl d via far-red light photoacclimation in a range of cyanobacteria, which enables them to use Near-Infrared-Radiation (NIR) for oxygenic photosynthesis. While the biochemistry and molecular physiology of Chl f-containing cyanobacteria has been unraveled in culture studies, their ecological significance remains unexplored and no data on their in situ activity exist. With a novel combination of hyperspectral imaging, confocal laser scanning microscopy, and nanoparticle-based O2 imaging, we demonstrate substantial NIR-driven oxygenic photosynthesis by endolithic, Chl f-containing cyanobacteria within natural beachrock biofilms that are widespread on (sub)tropical coastlines. This indicates an important role of NIR-driven oxygenic photosynthesis in primary production of endolithic and other shaded habitats.
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substantial Near Infrared Radiation driven photosynthesis of chlorophyll f containing cyanobacteria in a natural habitat
bioRxiv, 2019Co-Authors: Michael Kuhl, Erik Trampe, Maria Mosshammer, Michael Johnson, Anthony W D Larkum, Klaus KorenAbstract:Abstract Far-red absorbing chlorophylls are constitutively present as Chl d in the cyanobacterium Acaryochloris marina, or dynamically expressed by synthesis of Chl f and red-shifted phycobilins via far-red light photoacclimation in a range of cyanobacteria, which enables them to use Near-Infrared-Radiation (NIR) for oxygenic photosynthesis. While the biochemistry and molecular physiology of Chl f-containing cyanobacteria has been unraveled in culture studies, their ecological significance remains unexplored and no data on their in situ activity exist. With a novel combination of hyperspectral imaging, confocal laser scanning microscopy, and nanoparticle-based O2 imaging, we demonstrate substantial NIR-driven oxygenic photosynthesis by endolithic, Chl f-containing cyanobacteria within natural beachrock biofilms that are widespread on (sub)tropical coastlines. This indicates an important role of NIR-driven oxygenic photosynthesis in primary production of endolithic and other shaded habitats. Impact statement Cyanobacteria with chlorophyll f show substantial Near-Infrared Radiation-driven photosynthesis in intertidal habitats.
Natalia I Afanasyeva - One of the best experts on this subject based on the ideXlab platform.
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a novel mitochondrial signaling pathway activated by visible to Near Infrared Radiation
Photochemistry and Photobiology, 2004Co-Authors: Tiina I Karu, Ludmila V Pyatibrat, Natalia I AfanasyevaAbstract:Abstract The number of cells attached to glass substratum increases if HeLa cell suspension is irradiated with monochromatic visible-to-Near Infrared Radiation before plating (the action spectrum with maxima at 619, 657, 675, 700, 740, 760, 800, 820, 840 and 860 nm). Treating of cell suspension with sodium azide (2 × 10−5 M), sodium nitroprusside (5 × 10−5 M), ouabain (1 × 10−6 M) or amiloride (1.7 × 10−5 M) before irRadiation significantly modifies the spectrum of cell attachment enhancement. A light-induced mitochondrial signaling pathway can be regulated by small ligands directly binding to the catalytic center of cytochrome c oxidase (N3, NO) as well as by chemicals specifically binding to plasma membrane enzymes (ouabain, amiloride). The comparative analysis of action spectra allows the conclusions that first, CuA and CuB chromophores of cytochrome c oxidase could be involved as photoacceptors and second, various signaling pathways (reaction channels) between cytochrome c oxidase and cell attachment ...
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a novel mitochondrial signaling pathway activated by visible to Near Infrared Radiation
Photochemistry and Photobiology, 2004Co-Authors: Tiina I Karu, Ludmila V Pyatibrat, Natalia I AfanasyevaAbstract:The number of cells attached to glass substratum increases if HeLa cell suspension is irradiated with monochromatic visible-to-Near Infrared Radiation before plating (the action spectrum with maxima at 619, 657, 675, 700, 740, 760, 800, 820, 840 and 860 nm). Treating of cell suspension with sodium azide (2 x 10(-5) M), sodium nitroprusside (5 x 10(-5) M), ouabain (1 x 10(-6) M) or amiloride (1.7 x 10(-5) M) before irRadiation significantly modifies the spectrum of cell attachment enhancement. A light-induced mitochondrial signaling pathway can be regulated by small ligands directly binding to the catalytic center of cytochrome c oxidase (N(3), NO) as well as by chemicals specifically binding to plasma membrane enzymes (ouabain, amiloride). The comparative analysis of action spectra allows the conclusions that first, Cu(A) and Cu(B) chromophores of cytochrome c oxidase could be involved as photoacceptors and second, various signaling pathways (reaction channels) between cytochrome c oxidase and cell attachment regulation are at work.
Xiaoying Wang - One of the best experts on this subject based on the ideXlab platform.
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Near Infrared Radiation rescues mitochondrial dysfunction in cortical neurons after oxygen glucose deprivation
Metabolic Brain Disease, 2015Co-Authors: Ning Liu, Jianhua Zhao, Thomas Mccarthy, Clark E Tedford, Xiaoying WangAbstract:Near Infrared Radiation (NIR) is known to penetrate and affect biological systems in multiple ways. Recently, a series of experimental studies suggested that low intensity NIR may protect neuronal cells against a wide range of insults that mimic diseases such as stroke, brain trauma and neurodegeneration. However, the potential molecular mechanisms of neuroprotection with NIR remain poorly defined. In this study, we tested the hypothesis that low intensity NIR may attenuate hypoxia/ischemia-induced mitochondrial dysfunction in neurons. Primary cortical mouse neuronal cultures were subjected to 4 h oxygen-glucose deprivation followed by reoxygenation for 2 h, neurons were then treated with a 2 min exposure to 810-nm NIR. Mitochondrial function markers including MTT reduction and mitochondria membrane potential were measured at 2 h after treatment. Neurotoxicity was quantified 20 h later. Our results showed that 4 h oxygen-glucose deprivation plus 20 h reoxygenation caused 33.8 ± 3.4 % of neuron death, while NIR exposure significantly reduced neuronal death to 23.6 ± 2.9 %. MTT reduction rate was reduced to 75.9 ± 2.7 % by oxygen-glucose deprivation compared to normoxic controls, but NIR exposure significantly rescued MTT reduction to 87.6 ± 4.5 %. Furthermore, after oxygen-glucose deprivation, mitochondria membrane potential was reduced to 48.9 ± 4.39 % of normoxic control, while NIR exposure significantly ameliorated this reduction to 89.6 ± 13.9 % of normoxic control. Finally, NIR significantly rescued OGD-induced ATP production decline at 20 min after NIR. These findings suggest that low intensity NIR can protect neurons against oxygen-glucose deprivation by rescuing mitochondrial function and restoring neuronal energetics.
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Near Infrared Radiation protects against oxygen glucose deprivation induced neurotoxicity by down regulating neuronal nitric oxide synthase nnos activity in vitro
Metabolic Brain Disease, 2015Co-Authors: Ning Liu, Thomas Mccarthy, Clark E Tedford, Yunneng Jizhang, Xiaoying WangAbstract:Near Infrared Radiation (NIR) has been shown to be neuroprotective against neurological diseases including stroke and brain trauma, but the underlying mechanisms remain poorly understood. In the current study we aimed to investigate the hypothesis that NIR may protect neurons by attenuating oxygen-glucose deprivation (OGD)-induced nitric oxide (NO) production and modulating cell survival/death signaling. Primary mouse cortical neurons were subjected to 4 h OGD and NIR was applied at 2 h reoxygenation. OGD significantly increased NO level in primary neurons compared to normal control, which was significantly ameliorated by NIR at 5 and 30 min post-NIR. Neither OGD nor NIR significantly changed neuronal nitric oxide synthase (nNOS) mRNA or total protein levels compared to control groups. However, OGD significantly increased nNOS activity compared to normal control, and this effect was significantly diminished by NIR. Moreover, NIR significantly ameliorated the neuronal death induced by S-Nitroso-N-acetyl-DL-penicillamine (SNAP), a NO donor. Finally, NIR significantly rescued OGD-induced suppression of p-Akt and Bcl-2 expression, and attenuated OGD-induced upregulation of Bax, BAD and caspase-3 activation. These results suggest NIR may protect against OGD at least partially through reducing NO production by down-regulating nNOS activity, and modulating cell survival/death signaling.
Tiina I Karu - One of the best experts on this subject based on the ideXlab platform.
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a novel mitochondrial signaling pathway activated by visible to Near Infrared Radiation
Photochemistry and Photobiology, 2004Co-Authors: Tiina I Karu, Ludmila V Pyatibrat, Natalia I AfanasyevaAbstract:Abstract The number of cells attached to glass substratum increases if HeLa cell suspension is irradiated with monochromatic visible-to-Near Infrared Radiation before plating (the action spectrum with maxima at 619, 657, 675, 700, 740, 760, 800, 820, 840 and 860 nm). Treating of cell suspension with sodium azide (2 × 10−5 M), sodium nitroprusside (5 × 10−5 M), ouabain (1 × 10−6 M) or amiloride (1.7 × 10−5 M) before irRadiation significantly modifies the spectrum of cell attachment enhancement. A light-induced mitochondrial signaling pathway can be regulated by small ligands directly binding to the catalytic center of cytochrome c oxidase (N3, NO) as well as by chemicals specifically binding to plasma membrane enzymes (ouabain, amiloride). The comparative analysis of action spectra allows the conclusions that first, CuA and CuB chromophores of cytochrome c oxidase could be involved as photoacceptors and second, various signaling pathways (reaction channels) between cytochrome c oxidase and cell attachment ...
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a novel mitochondrial signaling pathway activated by visible to Near Infrared Radiation
Photochemistry and Photobiology, 2004Co-Authors: Tiina I Karu, Ludmila V Pyatibrat, Natalia I AfanasyevaAbstract:The number of cells attached to glass substratum increases if HeLa cell suspension is irradiated with monochromatic visible-to-Near Infrared Radiation before plating (the action spectrum with maxima at 619, 657, 675, 700, 740, 760, 800, 820, 840 and 860 nm). Treating of cell suspension with sodium azide (2 x 10(-5) M), sodium nitroprusside (5 x 10(-5) M), ouabain (1 x 10(-6) M) or amiloride (1.7 x 10(-5) M) before irRadiation significantly modifies the spectrum of cell attachment enhancement. A light-induced mitochondrial signaling pathway can be regulated by small ligands directly binding to the catalytic center of cytochrome c oxidase (N(3), NO) as well as by chemicals specifically binding to plasma membrane enzymes (ouabain, amiloride). The comparative analysis of action spectra allows the conclusions that first, Cu(A) and Cu(B) chromophores of cytochrome c oxidase could be involved as photoacceptors and second, various signaling pathways (reaction channels) between cytochrome c oxidase and cell attachment regulation are at work.
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photobiological modulation of cell attachment via cytochrome c oxidase
Photochemical and Photobiological Sciences, 2004Co-Authors: Tiina I Karu, Ludmila V Pyatibrat, G S KalendoAbstract:The number of cells attached to glass substrates increases if HeLa cell suspensions are irradiated with monochromatic visible-to-Near Infrared Radiation (600–860 nm, 52 J m−2) prior to plating. The well-structured relationship between this biological response and the Radiation wavelength (action spectrum with maxima at 620, 680, 760, and 820 nm) suggests the existence of a photoacceptor responsible for the enhancement of attachment (presumably cytochrome c oxidase, the terminal enzyme of the respiratory chain) and, secondly, the existence of signaling pathways between the mitochondria, the plasma membrane, and the nucleus of the cell. Treating the cell suspension with ouabain (a Na+, K+-ATPase inhibitor), amiloride (an inhibitor of N+/H+ exchangers), or sodium azide (a cytochrome c oxidase inhibitor) prior to irRadiation significantly modifies the action spectrum of cell attachment enhancement. The action of the chemicals under study also depends on their concentration and Radiation fluence. Our results point to the existence of at least three signaling pathways (reaction channels) relating together the cell attachment, the respiratory chain, and the Na+, K+-ATPase and N+/H+ exchanger activities.
