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Caddell D, Langenfeld NJ, Eckels MJH, Zhen S, Klaras R, Mishra L, Bugbee B, Coleman-Derr D. Photosynthesis in rice is increased by CRISPR/Cas9-mediated transformation of two truncated light-harvesting antenna. Front Plant Sci 2023; 14:1050483. [PMID: 36743495 PMCID: PMC9893291 DOI: 10.3389/fpls.2023.1050483] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/21/2022] [Accepted: 01/09/2023] [Indexed: 06/18/2023]
Abstract
Plants compete for light partly by over-producing chlorophyll in leaves. The resulting high light absorption is an effective strategy for out competing neighbors in mixed communities, but it prevents light transmission to lower leaves and limits photosynthesis in dense agricultural canopies. We used a CRISPR/Cas9-mediated approach to engineer rice plants with truncated light-harvesting antenna (TLA) via knockout mutations to individual antenna assembly component genes CpSRP43, CpSRP54a, and its paralog, CpSRP54b. We compared the photosynthetic contributions of these components in rice by studying the growth rates of whole plants, quantum yield of photosynthesis, chlorophyll density and distribution, and phenotypic abnormalities. Additionally, we investigated a Poales-specific duplication of CpSRP54. The Poales are an important family that includes staple crops such as rice, wheat, corn, millet, and sorghum. Mutations in any of these three genes involved in antenna assembly decreased chlorophyll content and light absorption and increased photosynthesis per photon absorbed (quantum yield). These results have significant implications for the improvement of high leaf-area-index crop monocultures.
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Affiliation(s)
- Daniel Caddell
- Plant Gene Expression Center, United States Department of Agriculture - Agricultural Research Service (USDA ARS), Albany, CA, United States
- Plant and Microbial Biology Department, University of California at Berkeley, Berkeley, CA, United States
| | - Noah J. Langenfeld
- Department of Plants, Soils, and Climate, Utah State University, Logan, UT, United States
| | - Madigan JH. Eckels
- Department of Plants, Soils, and Climate, Utah State University, Logan, UT, United States
| | - Shuyang Zhen
- Department of Horticultural Sciences, Texas A&M University, College Station, TX, United States
| | - Rachel Klaras
- Plant and Microbial Biology Department, University of California at Berkeley, Berkeley, CA, United States
| | - Laxmi Mishra
- Plant and Microbial Biology Department, University of California at Berkeley, Berkeley, CA, United States
| | - Bruce Bugbee
- Department of Plants, Soils, and Climate, Utah State University, Logan, UT, United States
| | - Devin Coleman-Derr
- Plant Gene Expression Center, United States Department of Agriculture - Agricultural Research Service (USDA ARS), Albany, CA, United States
- Plant and Microbial Biology Department, University of California at Berkeley, Berkeley, CA, United States
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Gjini M, Velten C, Brodin P, Tang J, Tome W, Zhen S, Guha C, Kabarriti R. Association between Liver Imaging Changes after Liver SBRT as Estimated by Area under the Dynamic Contrast-Enhanced MRI Curve and Changes in Global Liver Function. Int J Radiat Oncol Biol Phys 2022. [DOI: 10.1016/j.ijrobp.2022.07.425] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
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3
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Zhen S, van Iersel MW, Bugbee B. Photosynthesis in sun and shade: the surprising importance of far-red photons. New Phytol 2022; 236:538-546. [PMID: 35832002 DOI: 10.1111/nph.18375] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/01/2022] [Accepted: 07/07/2022] [Indexed: 06/15/2023]
Abstract
The current definition of photosynthetically active radiation includes only photons from 400 up to 700 nm, despite evidence of the synergistic interaction between far-red photons and shorter-wavelength photons. The synergy between far-red and shorter-wavelength photons has not been studied in sunlight under natural conditions. We used a filter to remove photons above 700 nm to quantify the effects on photosynthesis in diverse species under full sun, medium light intensity and vegetation shade. Far-red photons (701 to 750 nm) in sunlight are used efficiently for photosynthesis. This is especially important for leaves in vegetation shade, where far-red photons can be > 50% of the total incident photons between 400 and 750 nm. Far-red photons accounted for 24-25% of leaf gross photosynthesis (Pgross ) in a C3 and a C4 species when sunlight was filtered through a leaf, and 10-14% of leaf Pgross in a tree and an understory species in deep shade. Accounting for the photosynthetic activity of far-red photons is critical for accurate measurement and modeling of photosynthesis at single leaf, canopy and ecosystem scales. This, in turn, is crucial in understanding crop productivity, the global carbon cycle and climate change impacts on agriculture and ecosystems.
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Affiliation(s)
- Shuyang Zhen
- Department of Horticultural Sciences, Texas A&M University, College Station, TX, 77843, USA
| | - Marc W van Iersel
- Department of Horticulture, University of Georgia, Athens, GA, 30602, USA
| | - Bruce Bugbee
- Department of Plants, Soils and Climate, Utah State University, Logan, UT, 84341, USA
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Kang S, Kim JE, Zhen S, Kim J. Mild-Intensity UV-A Radiation Applied Over a Long Duration Can Improve the Growth and Phenolic Contents of Sweet Basil. Front Plant Sci 2022; 13:858433. [PMID: 35519818 PMCID: PMC9062229 DOI: 10.3389/fpls.2022.858433] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/20/2022] [Accepted: 03/28/2022] [Indexed: 06/14/2023]
Abstract
UV-A radiation (320-400 nm) is an abiotic stressor that may be used to enhance the production of beneficial secondary metabolites in crops such as leafy vegetables. However, tradeoffs between enhanced phytochemical contents and overall growth/yield reductions have been reported. The responses varied depending on the UV-A intensity, spectral peak, exposure time, species, and varieties. We quantified the changes in growth, morphology, photosynthesis, and phenolic contents of sweet basil grown under a base red/blue/green LED light with four supplemental UV-A intensity treatments (0, 10, 20, and 30 W·m-2) in an indoor environment over 14 days. The objective was to determine whether UV-A radiation could be utilized to improve both yield and quality of high-value sweet basil in a controlled production environment. Biomass harvested at 14 days after treatment (DAT) was highest under mild-intensity UV-A treatment of 10 W·m-2 and lowest under high-intensity UV-A treatment of 30 W·m-2. The total leaf area and the number of leaves were significantly lower under the 30 W·m-2 treatment than under the 10 and 20 W·m-2 treatments at 14 DAT. The maximum quantum efficiency of photosystem II (PSII) for photochemistry (Fv/Fm ) showed a gradual decrease under the 20 and 30 W·m-2 treatments from 3 to 14 DAT, whereas Fv/Fm remained relatively constant under the 0 and 10 W·m-2 treatments over the entire 14 days. The leaf net photosynthesis rate showed a significant decrease of 17.4% in the 30 W·m-2 treatment compared to that in the 10 W·m-2 treatment at 14 DAT. Phenolic contents (PAL enzyme activity, total phenolic concentration, and antioxidant capacity) were the highest under the 20 W·m-2 treatment, followed by the 10, 30, and 0 W·m-2 treatments. Overall, our results indicate that the biomass production and accumulation of beneficial phenolic compounds in sweet basil varied depending on the intensity and duration of UV-A application. Mild UV-A radiation (10-20 W·m-2) can be a beneficial stressor to improve sweet basil yield and quality over relatively long-term cultivation.
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Affiliation(s)
- Seonghwan Kang
- Department of Horticultural Sciences, Texas A&M University, College Station, TX, United States
| | - Jo Eun Kim
- Department of Horticultural Biotechnology, Korea University, Seoul, South Korea
| | - Shuyang Zhen
- Department of Horticultural Sciences, Texas A&M University, College Station, TX, United States
| | - Jongyun Kim
- Department of Plant Biotechnology, Korea University, Seoul, South Korea
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Kusuma P, Westmoreland FM, Zhen S, Bugbee B. Photons from NIR LEDs can delay flowering in short-day soybean and Cannabis: Implications for phytochrome activity. PLoS One 2021; 16:e0255232. [PMID: 34314454 PMCID: PMC8315492 DOI: 10.1371/journal.pone.0255232] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2021] [Accepted: 07/12/2021] [Indexed: 11/19/2022] Open
Abstract
Photons during the dark period delay flowering in short-day plants (SDP). Red photons applied at night convert phytochromes to the active far-red absorbing form (Pfr), leading to inhibition of flowering. Far-red photons (greater than 700 nm) re-induce flowering when applied after a pulse of red photons during the dark period. However, far-red photons at sufficiently high intensity and duration delay flowering in sensitive species. Mechanistically, this response occurs because phytochrome-red (Pr) absorbance is not zero beyond 700 nm. We applied nighttime photons from near infrared (NIR) LEDs (peak 850 nm) over a 12 h dark period. Flowering was delayed in Glycine max and Cannabis sativa (two photosensitive species) by 3 and 12 days, respectively, as the flux of photons from NIR LEDs was increased up to 83 and 116 μmol m-2 s-1. This suggests that long wavelength photons from NIR LEDs can activate phytochromes (convert Pr to Pfr) and thus alter plant development.
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Affiliation(s)
- Paul Kusuma
- Department of Plants Soils and Climate, Crop Physiology Laboratory, Utah State University, Logan, UT, United States of America
| | - F. Mitchell Westmoreland
- Department of Plants Soils and Climate, Crop Physiology Laboratory, Utah State University, Logan, UT, United States of America
| | - Shuyang Zhen
- Department of Horticultural Sciences, Texas A&M University, College Station, TX, United States of America
| | - Bruce Bugbee
- Department of Plants Soils and Climate, Crop Physiology Laboratory, Utah State University, Logan, UT, United States of America
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Zhen S, van Iersel M, Bugbee B. Why Far-Red Photons Should Be Included in the Definition of Photosynthetic Photons and the Measurement of Horticultural Fixture Efficacy. Front Plant Sci 2021; 12:693445. [PMID: 34239530 PMCID: PMC8258408 DOI: 10.3389/fpls.2021.693445] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/11/2021] [Accepted: 05/20/2021] [Indexed: 05/27/2023]
Affiliation(s)
- Shuyang Zhen
- Department of Horticultural Sciences, Texas A&M University, College Station, TX, United States
| | - Marc van Iersel
- Department of Horticulture, University of Georgia, Athens, GA, United States
| | - Bruce Bugbee
- Department of Plants, Soils and Climate, Utah State University, Logan, UT, United States
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Zhen S, Bugbee B. Steady-state stomatal responses of C 3 and C 4 species to blue light fraction: Interactions with CO 2 concentration. Plant Cell Environ 2020; 43:3020-3032. [PMID: 32929764 DOI: 10.1111/pce.13888] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/22/2020] [Accepted: 09/09/2020] [Indexed: 06/11/2023]
Abstract
Blue light induced stomatal opening has been studied by applying a short pulse (~5 to 60 s) of blue light to a background of saturating photosynthetic red photons, but little is known about steady-state stomatal responses. Here we report stomatal responses to blue light at high and low CO2 concentrations. Steady-state stomatal conductance (gs ) of C3 plants increased asymptotically with increasing blue light to a maximum at 20% blue (120 μmol m-2 s-1 ). This response was consistent from 200 to 800 μmol mol-1 atmospheric CO2 (Ca ). In contrast, blue light induced only a transient stomatal opening (~5 min) in C4 species above a Ca of 400 μmol mol-1 . Steady-state gs of C4 plants generally decreased with increasing blue intensity. The net photosynthetic rate of all species decreased above 20% blue because blue photons have lower quantum yield (moles carbon fixed per mole photons absorbed) than red photons. Our findings indicate that photosynthesis, rather than a blue light signal, plays a dominant role in stomatal regulation in C4 species. Additionally, we found that blue light affected only stomata on the illuminated side of the leaf. Contrary to widely held belief, the blue light-induced stomatal opening minimally enhanced photosynthesis and consistently decreased water use efficiency.
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Affiliation(s)
- Shuyang Zhen
- Crop Physiology Laboratory, Department of Plants Soils and Climate, Utah State University, Logan, Utah, USA
| | - Bruce Bugbee
- Crop Physiology Laboratory, Department of Plants Soils and Climate, Utah State University, Logan, Utah, USA
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8
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Zhen S, Bugbee B. Steady-state stomatal responses of C 3 and C 4 species to blue light fraction: Interactions with CO 2 concentration. Plant Cell Environ 2020; 43:1259-1272. [PMID: 32929764 DOI: 10.1111/pce.13730] [Citation(s) in RCA: 67] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/23/2019] [Revised: 01/21/2020] [Accepted: 01/22/2020] [Indexed: 05/22/2023]
Abstract
Blue light induced stomatal opening has been studied by applying a short pulse (~5 to 60 s) of blue light to a background of saturating photosynthetic red photons, but little is known about steady-state stomatal responses. Here we report stomatal responses to blue light at high and low CO2 concentrations. Steady-state stomatal conductance (gs ) of C3 plants increased asymptotically with increasing blue light to a maximum at 20% blue (120 μmol m-2 s-1 ). This response was consistent from 200 to 800 μmol mol-1 atmospheric CO2 (Ca ). In contrast, blue light induced only a transient stomatal opening (~5 min) in C4 species above a Ca of 400 μmol mol-1 . Steady-state gs of C4 plants generally decreased with increasing blue intensity. The net photosynthetic rate of all species decreased above 20% blue because blue photons have lower quantum yield (moles carbon fixed per mole photons absorbed) than red photons. Our findings indicate that photosynthesis, rather than a blue light signal, plays a dominant role in stomatal regulation in C4 species. Additionally, we found that blue light affected only stomata on the illuminated side of the leaf. Contrary to widely held belief, the blue light-induced stomatal opening minimally enhanced photosynthesis and consistently decreased water use efficiency.
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Affiliation(s)
- Shuyang Zhen
- Crop Physiology Laboratory, Department of Plants Soils and Climate, Utah State University, Logan, Utah, USA
| | - Bruce Bugbee
- Crop Physiology Laboratory, Department of Plants Soils and Climate, Utah State University, Logan, Utah, USA
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9
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Zhen S, Bugbee B. Substituting Far-Red for Traditionally Defined Photosynthetic Photons Results in Equal Canopy Quantum Yield for CO 2 Fixation and Increased Photon Capture During Long-Term Studies: Implications for Re-Defining PAR. Front Plant Sci 2020; 11:581156. [PMID: 33014004 PMCID: PMC7516038 DOI: 10.3389/fpls.2020.581156] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/08/2020] [Accepted: 08/31/2020] [Indexed: 05/27/2023]
Abstract
Far-red photons regulate shade avoidance responses and can have powerful effects on plant morphology and radiation capture. Recent studies have shown that far-red photons (700 to 750 nm) efficiently drive photosynthesis when added to traditionally defined photosynthetic photons (400-700 nm). But the long-term effects of far-red photons on canopy quantum yield have not yet been determined. We grew lettuce in a four-chamber, steady-state canopy gas-exchange system to separately quantify canopy photon capture, quantum yield for CO2 fixation, and carbon use efficiency. These measurements facilitate a mechanistic understanding of the effect of far-red photons on the components of plant growth. Day-time photosynthesis and night-time respiration of lettuce canopies were continuously monitored from seedling to harvest in five replicate studies. Plants were grown under a background of either red/blue or white light, each background with or without 15% (50 μmol m-2 s-1) of far-red photons substituting for photons between 400 and 700 nm. All four treatments contained 31.5% blue photons, and an equal total photon flux from 400 to 750 nm of 350 μmol m-2 s-1. Both treatments with far-red photons had higher canopy photon capture, increased daily carbon gain (net photosynthesis minus respiration at night), and 29 to 31% more biomass than control treatments. Canopy quantum yield was similar among treatments (0.057 ± 0.002 mol of CO2 fixed in gross photosynthesis per mole of absorbed photons integrated over 400 to 750 nm). Carbon use efficiency (daily carbon gain/gross photosynthesis) was also similar for mature plants (0.61 ± 0.02). Photosynthesis increased linearly with increasing photon capture and had a common slope among all four treatments, which demonstrates that the faster growth with far-red photon substitution was caused by enhanced photon capture through increased leaf expansion. The equivalent canopy quantum yield among treatments indicates that the absorbed far-red photons were equally efficient for photosynthesis when acting synergistically with the 400-700 nm photons.
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Zhen S, Haidekker M, van Iersel MW. Far-red light enhances photochemical efficiency in a wavelength-dependent manner. Physiol Plant 2019; 167:21-33. [PMID: 30203475 DOI: 10.1111/ppl.12834] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2018] [Revised: 09/04/2018] [Accepted: 09/07/2018] [Indexed: 05/21/2023]
Abstract
Linear electron transport depends on balanced excitation of photosystem I and II. Far-red light preferentially excites photosystem I (PSI) and can enhance the photosynthetic efficiency when combined with light that over-excites photosystem II (PSII). The efficiency of different wavelengths of far-red light exciting PSI was quantified by measuring the change in quantum yield of PSII (ΦPSII ) of lettuce (Lactuca sativa) under red/blue light with narrowband far-red light added (from 678 to 752 nm, obtained using laser diodes). The ΦPSII of lettuce increased with increasing wavelengths of added light from 678 to 703 nm, indicating longer wavelengths within this region are increasingly used more efficiently by PSI than by PSII. Adding 721 nm light resulted in similar ΦPSII as adding 703 nm light, but ΦPSII tended to decrease as wavelength increased from 721 to 731 nm, likely due to decreasing absorptance and low photon energy. Adding 752 nm light did not affect ΦPSII . Leaf chlorophyll fluorescence light response measurements showed lettuce had higher ΦPSII under halogen light (rich in far-red) than under red/blue light (which over-excites PSII). Far-red light is more photosynthetically active than commonly believed, because of its synergistic interaction with light of shorter wavelengths.
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Affiliation(s)
- Shuyang Zhen
- Department of Horticulture, University of Georgia, Athens, GA, 30602, USA
| | - Mark Haidekker
- College of Engineering, University of Georgia, Athens, GA, 30602, USA
| | - Marc W van Iersel
- Department of Horticulture, University of Georgia, Athens, GA, 30602, USA
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11
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Soundararajan M, Ledbetter R, Kusuma P, Zhen S, Ludden P, Bugbee B, Ensign SA, Seefeldt LC. Phototrophic N 2 and CO 2 Fixation Using a Rhodopseudomonas palustris-H 2 Mediated Electrochemical System With Infrared Photons. Front Microbiol 2019; 10:1817. [PMID: 31474945 PMCID: PMC6705187 DOI: 10.3389/fmicb.2019.01817] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2018] [Accepted: 07/23/2019] [Indexed: 11/13/2022] Open
Abstract
A promising approach for the synthesis of high value reduced compounds is to couple bacteria to the cathode of an electrochemical cell, with delivery of electrons from the electrode driving reductive biosynthesis in the bacteria. Such systems have been used to reduce CO2 to acetate and other C-based compounds. Here, we report an electrosynthetic system that couples a diazotrophic, photoautotrophic bacterium, Rhodopseudomonas palustris TIE-1, to the cathode of an electrochemical cell through the mediator H2 that allows reductive capture of both CO2 and N2 with all of the energy coming from the electrode and infrared (IR) photons. R. palustris TIE-1 was shown to utilize a narrow band of IR radiation centered around 850 nm to support growth under both photoheterotrophic, non-diazotrophic and photoautotrophic, diazotrophic conditions with growth rates similar to those achieved using broad spectrum incandescent light. The bacteria were also successfully cultured in the cathodic compartment of an electrochemical cell with the sole source of electrons coming from electrochemically generated H2, supporting reduction of both CO2 and N2 using 850 nm photons as an energy source. Growth rates were similar to non-electrochemical conditions, revealing that the electrochemical system can fully support bacterial growth. Faradaic efficiencies for N2 and CO2 reduction were 8.5 and 47%, respectively. These results demonstrate that a microbial-electrode hybrid system can be used to achieve reduction and capture of both CO2 and N2 using low energy IR radiation and electrons provided by an electrode.
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Affiliation(s)
- Mathangi Soundararajan
- Department of Chemistry and Biochemistry, Utah State University, Logan, UT, United States
| | - Rhesa Ledbetter
- Department of Biological Sciences, Idaho State University, Pocatello, ID, United States
| | - Paul Kusuma
- Department of Plant, Soils and Climate, Utah State University, Logan, UT, United States
| | - Shuyang Zhen
- Department of Plant, Soils and Climate, Utah State University, Logan, UT, United States
| | - Paul Ludden
- Department of Biology, Southern Methodist University, Dallas, TX, United States
| | - Bruce Bugbee
- Department of Plant, Soils and Climate, Utah State University, Logan, UT, United States
| | - Scott A Ensign
- Department of Chemistry and Biochemistry, Utah State University, Logan, UT, United States
| | - Lance C Seefeldt
- Department of Chemistry and Biochemistry, Utah State University, Logan, UT, United States
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Zhen S, van Iersel MW. Far-red light is needed for efficient photochemistry and photosynthesis. J Plant Physiol 2017; 209:115-122. [PMID: 28039776 DOI: 10.1016/j.jplph.2016.12.004] [Citation(s) in RCA: 70] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2016] [Revised: 12/12/2016] [Accepted: 12/13/2016] [Indexed: 05/20/2023]
Abstract
The efficiency of monochromatic light to drive photosynthesis drops rapidly at wavelengths longer than 685nm. The photosynthetic efficiency of these longer wavelengths can be improved by adding shorter wavelength light, a phenomenon known as the Emerson enhancement effect. The reverse effect, the enhancement of photosynthesis under shorter wavelength light by longer wavelengths, however, has not been well studied and is often thought to be insignificant. We quantified the effect of adding far-red light (peak at 735nm) to red/blue or warm-white light on the photosynthetic efficiency of lettuce (Lactuca sativa). Adding far-red light immediately increased quantum yield of photosystem II (ΦPSII) of lettuce by an average of 6.5 and 3.6% under red/blue and warm-white light, respectively. Similar or greater increases in ΦPSII were observed after 20min of exposure to far-red light. This longer-term effect of far-red light on ΦPSII was accompanied by a reduction in non-photochemical quenching of fluorescence (NPQ), indicating that far-red light reduced the dissipation of absorbed light as heat. The increase in ΦPSII and complementary decrease in NPQ is presumably due to preferential excitation of photosystem I (PSI) by far-red light, which leads to faster re-oxidization of the plastoquinone pool. This facilitates reopening of PSII reaction centers, enabling them to use absorbed photons more efficiently. The increase in ΦPSII by far-red light was associated with an increase in net photosynthesis (Pn). The stimulatory effect of far-red light increased asymptotically with increasing amounts of far-red. Overall, our results show that far-red light can increase the photosynthetic efficiency of shorter wavelength light that over-excites PSII.
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Affiliation(s)
- Shuyang Zhen
- Department of Horticulture, University of Georgia, 1111 Miller Plant Science Building, Athens, GA 30602, USA.
| | - Marc W van Iersel
- Department of Horticulture, University of Georgia, 1111 Miller Plant Science Building, Athens, GA 30602, USA.
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Mayyas E, Vance S, Brown S, Liu J, Kim J, Zhen S, Devpura S, Ajlouni M, Salim S, Chetty I, Movsas B. WE-AB-207B-12: Prospective Study of the Relationship Between Dose-Volume Clinical Toxicity and Patient Reported Outcomes in Lung Cancer Patients Treated with SBRT. Med Phys 2016. [DOI: 10.1118/1.4957793] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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Wang X, Luo H, Wang J, Chen C, Cai Y, Zhen S, Zhou L, Zeng C. ASSA14-03-07 PrenatalLipopolysaccharideExposure Results in Dysfunction of Renal Dopamine D1Receptor in Offspring Rats. Heart 2015. [DOI: 10.1136/heartjnl-2014-307109.26] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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15
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Shi Z, Zhen S, Qi L, Zhou Y, Taylor A. Rice intake is inversely related to cardiovascular mortality among Chinese adults. Journal of Nutrition & Intermediary Metabolism 2014. [DOI: 10.1016/j.jnim.2014.10.090] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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Abstract
BCSC-1 is dramatically upregulated in CNE-2L2 human nasopharyngeal carcinoma cells with reduced malignancy (AS cells) and is proposed to be a candidate tumor suppressor gene. We therefore examined the effect of BCSC-1 expression on malignant behaviors of CNE-2L2 cells. Growth in vitro and tumorigenesis in nude mice of wild-type CNE-2L2 cells (W cells) were inhibited by ectopic BCSC-1, and those of AS cells were promoted by BCSC-1 suppression. The tumor suppressor function of BCSC-1 was further confirmed by a study showing that intratumor BCSC-1 injection caused growth suppression of the tumor from W cells inoculated in nude mice. Immunohistochemistry exhibited marked reduction of BCSC-1 expression in 11 of 39 human nasopharyngeal carcinoma specimens. Because BCSC-1 expression was as rich as that in normal cells in the rest of the carcinoma specimens and was poor in CNE-2L2 cells, HNE-1 human nasopharyngeal carcinoma cells with rich BCSC-1 expression were used as a control in the study. No effect of BCSC-1 transfection on growth of the cells was observed. The data suggest that BCSC-1 suppression might play roles in tumorigenesis of some nasopharyngeal carcinomas and that BCSC-1 might be a potential gene therapy target in nasopharyngeal carcinomas with poor BCSC-1 expression. Enhanced aggregation of cells together with increased E-cadherin and alpha-catenin expression and reduced Wnt signaling might be involved in the mechanisms of tumor suppressor function of BCSC-1.
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Affiliation(s)
- Y Q Zhou
- Department of Immunology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and School of Basic Medicine, Peking Union Medical College, Beijing, China
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Zhen S, Zakaria M, Wolfe A, Radovick S. Regulation of gonadotropin-releasing hormone (GnRH) gene expression by insulin-like growth factor I in a cultured GnRH-expressing neuronal cell line. Mol Endocrinol 1997; 11:1145-55. [PMID: 9212061 DOI: 10.1210/mend.11.8.9956] [Citation(s) in RCA: 50] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
A GnRH-expressing neuronal cell line (NLT) was used to determine whether insulin-like growth factor I (IGF-I) regulates GnRH gene expression. A receptor-binding assay demonstrated the expression of IGF-I receptors on NLT cells. Activation of IGF-I receptors induced the Ras/Raf-1/mitogen-activated protein kinase pathway and increased c-fos expression. NLT cells treated with IGF-I underwent cell proliferation and exhibited a growth-independent increase in mouse GnRH mRNA expression. In cells transfected with DNA constructs containing the human GnRH promoter, which includes a consensus AP-1 binding site fused to the luciferase reporter gene, a significant increase in reporter activities was induced by IGF-I, whereas mutation of this AP-1 site significantly reduced IGF-I-induced promoter activation. These results demonstrate that IGF-I serves as an important signal in the regulation of both human and rodent GnRH gene expression.
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Affiliation(s)
- S Zhen
- Division of Endocrinology, Children's Hospital, Harvard Medical School, Boston, Massachusetts 02115, USA
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Zhen S, Dunn IC, Wray S, Liu Y, Chappell PE, Levine JE, Radovick S. An alternative gonadotropin-releasing hormone (GnRH) RNA splicing product found in cultured GnRH neurons and mouse hypothalamus. J Biol Chem 1997; 272:12620-5. [PMID: 9139717 DOI: 10.1074/jbc.272.19.12620] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Gonadotropin-releasing hormone (GnRH) is encoded by the proGnRH gene which contains four exons and three introns. In this study, two immortalized GnRH-expressing cell lines (Gn11 and NLT) were characterized. The NLT and Gn11 cells, derived from a same brain tumor in a transgenic mouse, display neuronal morphology and neuron-specific markers. However, NLT cells secrete much higher levels of GnRH than Gn11 cells. To delineate the mechanism underlying this difference, reverse transcriptase-polymerase chain reaction and RNase protection assays were performed to examine proGnRH gene expression. While the mature proGnRH mRNA was predominately expressed in NLT cells, Gn11 cells express an abundant short transcript. Sequence analysis revealed that this short transcript contains exons 1, 3, and 4, but not exon 2, which encodes the GnRH decapeptide. RNase protection assays demonstrated that NLT cells express much higher levels of mature proGnRH mRNA than Gn11 cells. The lower level of GnRH secreting capacity in Gn11 cells is due, in part, to decreased expression of mature proGnRH mRNA. When proGnRH gene expression in the mouse brain was examined, the same short splicing variant was observed in the olfactory area and preoptic area-anterior hypothalamus. But the prevalent transcript in these regions was the mature proGnRH mRNA. In contrast, only the mature proGnRH mRNA was found in the caudal hypothalamus. These results suggest that alternative splicing may be one of the mechanisms regulating proGnRH gene expression in the animal brain.
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Affiliation(s)
- S Zhen
- Department of Medicine, Division of Endocrinology, Children's Hospital, Harvard Medical School, Boston, Massachusetts 02115, USA
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Zakaria M, Dunn IC, Zhen S, Su E, Smith E, Patriquin E, Radovick S. Phorbol ester regulation of the gonadotropin-releasing hormone (GnRH) gene in GnRH-secreting cell lines: a molecular basis for species differences. Mol Endocrinol 1996; 10:1282-91. [PMID: 9121495 DOI: 10.1210/mend.10.10.9121495] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Phorbol ester 12-O-tetradecanoyl phorbol-13-acetate (TPA) regulation of the GnRH gene was studied in two mouse GnRH neuronal cell lines, Gn11 and NLT. TPA treatment of NLT cells grown in low serum conditions did not alter endogenous mouse GnRH mRNA levels, indicating that the endogenous mouse gene is not regulated by phorbol esters under these conditions. This result is confirmed in transfection studies in which TPA treatment did not change expression of a mouse GnRH-luciferase reporter gene construct. In contrast, TPA treatment stimulated expression of a human GnRH-luciferase reporter construct, correlating with the expression of the protoon-cogenes c-fos and c-jun. TPA stimulation of the human GnRH gene is mediated by a consensus AP-1 site located at -402 to -396 bp, TGACTCA, which specifically binds c-fos and c-jun in Gn11 and NLT cells and recombinant c-jun in gel mobility shift studies. In contrast, the rodent GnRH genes, when aligned for maximum homology, contain a DNA sequence with a 1-bp difference, TGTCTCA from the human gene. In gel mobility shift studies, this DNA sequence does not form a complex with Gn11 or NLT nuclear extract or with recombinant c-jun. This is the first demonstration of species-specific differences in phorbol ester regulation of GnRH gene transcription and could, in part, explain differences in reproductive function among mammals.
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Affiliation(s)
- M Zakaria
- Department of Medicine, Children's Hospital, Boston, Massachusetts, USA
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Zhen S, Gallo RV. The role of norepinephrine in mediating luteinizing hormone release in response to blockade of kappa-opioid receptors in the medial preoptic area. Brain Res 1995; 698:121-9. [PMID: 8581470 DOI: 10.1016/0006-8993(95)00874-p] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Our previous study [32] indicated that blockade of kappa-opioid receptors with nor-binaltorphimine (nor-BNI) in the medial preoptic area (MPOA) produced two different LH responses during midpregnancy in the rat: an increase in basal pulsatile LH secretion, followed in many cases by a larger and/or sustained increase in LH release. In the present study, two experiments were conducted to examine the role of norepinephrine (NE) in mediating these different LH responses. In experiment 1, the effects of NE synthesis inhibition with FLA-63 on nor-BNI induced LH secretion were examined. In 5 of 9 vehicle pretreated rats, nor-BNI perfusion in the MPOA produced only an increase in basal pulsatile LH secretion. In the remaining 4 animals blockade of MPOA kappa-receptors produced not only an increase in basal LH secretion, but also a large/sustained release of LH. Pretreatment with FLA-63 had no effect on the nor-BNI induced increase in basal pulsatile LH secretion, but completely prevented the occurrence of the large/sustained release of LH. The objective of experiment 2 was to determine whether any change in NE release occurred at the site of nor-BNI perfusion in rats showing this large/sustained increase in plasma LH levels, by measuring in vivo NE release at that site. No significant change in perfusate NE levels was observed during perfusion of the MPOA with nor-BNI alone or in combination with desipramine, a NE reuptake blocker, in rats that showed this type of LH response. These results demonstrate that while NE does not mediate the increase in basal pulsatile LH release produced by nor-BNI perfusion in the MPOA, it is essential for the large/sustained elevation in LH secretion seen in response to blockade of kappa-opioid receptors at this site. This latter type of LH secretory response is not, however, associated with an increase in NE release directly at the site of kappa-opioid receptor blockade in the MPOA in pregnant rats.
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Affiliation(s)
- S Zhen
- Department of Physiology and Neurobiology, University of Connecticut, Storrs 06269-4154, USA
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Yuqin M, Zhonglun Z, Zhen S, Bin M, Yanzhen Z, Chengxiang L, Yingyan W, Jiguang W. SO2-induced change of spectrum in low-level chemiluminescence from leaf of Populus tomentosa. Bull Environ Contam Toxicol 1995; 55:136-141. [PMID: 7663083 DOI: 10.1007/bf00212400] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Affiliation(s)
- M Yuqin
- Institute of Biophysics, Academia Sinica, Beijing, People's Republic of China
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Zhen S, Gallo RV. Lack of catecholamine involvement in the increased luteinizing hormone release due to blockade of kappa-opioid receptors in the medial basal hypothalamus during midpregnancy in the rat. Brain Res 1994; 642:178-84. [PMID: 8032878 DOI: 10.1016/0006-8993(94)90920-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Blockade of kappa-opioid receptors in the medial basal hypothalamus (MBH) with nor-binaltorphimine (nor-BNI) stimulates luteinizing hormone (LH) release during midpregnancy in the rat [48]. The objective of this study was to determine whether norepinephrine (NE) or dopamine (DA) mediates the LH response to blockade of MBH kappa-opioid receptors on days 13-17 of pregnancy in the rat. Two experiments were conducted. In the first, push-pull perfusion in conjunction with HPLC was used to monitor in vivo NE release in the MBH occurring in response to (a) artificial CSF followed by CSF containing nor-BNI (40 micrograms/h), (b) desipramine (DMI, a NE reuptake blocker, 10 microM) in CSF followed by DMI, and (c) DMI followed by DMI+nor-BNI. Blood samples were taken at 12 min intervals concurrent with push-pull perfusate samples. Plasma LH levels were determined by RIA. Nor-BNI significantly increased LH release compared to CSF alone, but perfusate NE was undetectable in either perfusion period. However, perfusion with CSF containing 100 mM K+ in these rats markedly increased perfusate NE levels, indicating noradrenergic nerve terminals were present at the perfusion sites in the MBH. Addition of DMI to the CSF significantly increased perfusate NE levels, but produced no change in LH release. Nor-BNI+DMI perfusion increased LH secretion similar to nor-BNI alone, but produced no additional increase in MBH perfusate NE levels compared to perfusion with DMI alone.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- S Zhen
- Department of Physiology and Neurobiology, University of Connecticut, Storrs 06269-4154
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Zhen S, Gallo RV. The effect of blockade of kappa-opioid receptors in the medial basal hypothalamus and medial preoptic area on luteinizing hormone release during midpregnancy in the rat. Endocrinology 1992; 131:1650-6. [PMID: 1327717 DOI: 10.1210/endo.131.4.1327717] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
The objective of this study was to determine if kappa-opioid receptors present in the medial preoptic area (MPOA) and medial basal hypothalamus (MBH) are involved in opioid peptide suppression of LH secretion during midpregnancy (day 13-16) in the rat. Nor-binaltorphimine (nor-BNI), a selective antagonist of brain kappa-opioid receptors, was applied directly to the MPOA or MBH for 3.5 h by means of push-pull perfusion. Nor-BNI perfusion in the MBH produced a dose-dependent increase in LH pulse frequency as well as increases in blood LH level. The effect on amplitude could not be determined, since too few pulses occurred in cerebrospinal fluid-treated control rats. Nor-BNI perfusion in the MPOA also increased LH pulse frequency. Moreover, in the majority (62%) of rats perfused with nor-BNI in the MPOA, the final 1.5 h of perfusion were unexpectedly characterized by an increase in LH that was of greater magnitude and more prolonged than an LH pulse and produced an elevation in blood LH levels. This delayed LH response did not occur in any rat perfused in the MBH. Perfusion with nor-BNI in the diagonal band of Broca had no significant effect on LH secretion. The LH responses observed during nor-BNI perfusion in the MPOA or MBH were not due to spread to the third ventricle and subsequent diffusion via the cerebrospinal fluid to another brain site, since perfusion with nor-BNI in an area of the ventral thalamus close to the third ventricle had no effect on LH release. These results provide support for the involvement of kappa-opioid receptor-mediated mechanisms in both the MPOA and MBH in the suppression of LH secretion during midgestation in the rat.
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Affiliation(s)
- S Zhen
- Department of Physiology and Neurobiology, University of Connecticut, Storrs 06269-4154
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Koo DS, Zhen S, Zhen ZD, Shi XW, Xiang SJ. Assessment of topical therapy of the burn wound with silver sulphadiazine after its use for 15 years in a burn unit. Burns 1989; 15:193-6. [PMID: 2757770 DOI: 10.1016/0305-4179(89)90182-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
A comparative study of patients receiving or not receiving topical applications of 1 per cent silver sulphadiazine cream as treatment for burn wounds has shown that the drug is still effective in significantly reducing the amount of bacterial contamination of burn wounds, even after 15 years of use in our Burn Unit. Consequently the overall mortality due to burn wound sepsis has been decreased in this Burn Unit.
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Affiliation(s)
- D S Koo
- Burn Unit, Rui Jin Hospital, Shanghai Second Medical Univeristy, China
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