Far-red illumination of plant leaves for a few seconds induces a delayed luminescence rise, or afterglow, that can be measured with the thermoluminescence technique as a sharp band peaking at around 40-45 degrees C. The afterglow band is attributable to a heat-induced electron flow from the stroma to the plastoquinone pool and the PSII centers. Using various Arabidopsis and tobacco mutants, we show here that the electron fluxes reflected by the afterglow luminescence follow the pathways of cyclic electron transport around PSI. In tobacco, the afterglow signal relied mainly on the ferredoxin-quinone oxidoreductase (FQR) activity while the predominant pathway responsible for the afterglow in Arabidopsis involved the NAD(P)H dehydrogenase (NDH) complex. The peak temperature T(m) of the afterglow band varied markedly with the light conditions prevailing before the TL measurements, from around 30 degrees C to 45 degrees C in Arabidopsis. These photoinduced changes in Tm followed the same kinetics and responded to the same light stimuli as the state 1-state 2 transitions. PSII-exciting light (leading to state 2) induced a downward shift while preillumination with far-red light (inducing state 1) caused an upward shift. However, the light-induced downshift was strongly inhibited in NDH-deficient Arabidopsis mutants and the upward shift was cancelled in plants durably acclimated to high light, which can perform normal state transitions. Taken together, our results suggest that the peak temperature of the afterglow band is indicative of regulatory processes affecting electron donation to the PQ pool which could involve phosphorylation of NDH. The afterglow thermoluminescence band provides a new and simple tool to investigate the cyclic electron transfer pathways and to study their regulation in vivo.
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http://dx.doi.org/10.1016/j.bbabio.2005.07.010 | DOI Listing |
Adv Sci (Weinh)
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Center for High-Pressure Science, State Key Laboratory of Metastable Materials Science and Technology, School of Science, Yanshan University, Qinhuangdao, 066004, China.
Oxygen usually exists in the form of diatomic molecules at ambient conditions. At high pressure, it undergoes a series of phase transitions from diatomic O to O cluster and ultimately dissociates into a polymeric O spiral chain structure. Intriguingly, the commonly found cyclic hexameric molecules in other group VIA elements (e.
View Article and Find Full Text PDFBiosensors (Basel)
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LABEL-Laboratório de Bioeletrônica e Eletroanalítica, Central Analítica Multidisciplinar, Universidade Federal do Amazonas, Manaus 69067-005, Amazonas, Brazil.
Biosensors harness biological materials as receptors linked to transducers, enabling the capture and transformation of primary biorecognition signals into measurable outputs. This study presents a novel carboxylation method for synthesizing carboxylated graphene (CG) under acidic conditions, enhancing biosensing capabilities. The characterization of the CG was performed using scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), Raman spectroscopy, thermogravimetric analysis (TGA), and X-ray diffraction (XRD).
View Article and Find Full Text PDFDent J (Basel)
January 2025
Department of Oral Rehabilitation, The Maurice and Gabriela Goldschleger School of Dental Medicine, Faculty of Medicine, Tel Aviv University, Tel Aviv 6997801, Israel.
: The success of treatment and prevention for secondary caries hinges significantly on the techniques employed in Class II composite restoration. Additionally, the location of the restored tooth within the oral cavity has emerged as a potential factor determining the quality of the restoration. A comprehensive understanding of these interrelated variables is crucial for advancing the efficacy and durability of dental composite restorations.
View Article and Find Full Text PDFACS Appl Mater Interfaces
January 2025
Key Laboratory of Green Chemical and Clean Energy Technology, School of Chemistry and Chemical Engineering, Guizhou University, Guiyang 550025, P. R. China.
Electron-induced effects, which are prevalent in adsorption and heterogeneous catalytic reactions, can significantly influence the state and uptake of adsorbates. Here, we demonstrate the in situ doping of electron-deficient boron into the backbone of chitosan-based porous carbon materials. Despite a reduction in specific surface area, the resulting boron-doped porous carbons (NBPCs) exhibit an enhanced CO adsorption performance, with sample NBPC-10 achieving CO adsorption capacities of 7.
View Article and Find Full Text PDFBMC Oral Health
January 2025
Department of Conservative Dentistry, School of Dentistry, Dental Research Institute, Dental and Life Science Institute, Pusan National University, Yangsan, Korea.
Background: This study compared the torsional resistance, bending stiffness, and cyclic fatigue resistances of different heat-treated NiTi files for minimally invasive instrumentation.
Methods: TruNatomy (TN) and EndoRoad (ER) file systems were compared with ProTaper Gold (PG). Torsional load, distortion angle, and bending stiffness were assessed using a custom device AEndoS, and toughness was calculated using the torsional data.
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