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https://www.readbyqxmd.com/read/28922753/effects-of-periodic-photoinhibitory-light-exposure-on-physiology-and-productivity-of-arabidopsis-plants-grown-under-low-light
#1
Yonglan Tian, Joanna Sacharz, Maxwell A Ware, Huayong Zhang, Alexander V Ruban
This work examined the long-term effects of periodic high light stress on photosynthesis, morphology, and productivity of low-light-acclimated Arabidopsis plants. Significant photoinhibition of Arabidopsis seedlings grown under low light (100 μmol photons m-2 s-1) was observed at the beginning of the high light treatment (three times a day for 30 min at 1800 μmol photons m-2 s-1). However, after 2 weeks of treatment, similar photosynthesis yields (Fv/Fm) to those of control plants were attained. The daily levels of photochemical quenching measured in the dark (qPd) indicated that the plants recovered from photoinhibition within several hours once transferred back to low light conditions, with complete recovery being achieved overnight...
July 10, 2017: Journal of Experimental Botany
https://www.readbyqxmd.com/read/28922537/encapsulation-of-isolated-luminophores-within-supramolecular-cages
#2
Marcel Handke, Takuji Adachi, Chunhua Hu, Michael D Ward
The sequestration of luminophores within supramolecular polyhedral compartments of a crystalline zeolite-like hydrogen-bonded framework illustrates a unique approach to limiting the self-quenching ordinarily exhibited at the high concentrations achievable in this framework. A range of differently sized luminescent guests, namely coumarin 1, coumarin 4, fluorescein, [Ru(bpy)3 ]Cl2 , and rhodamine B, can be encapsulated in amounts of up to one molecule per cage, equivalent to a concentration of 0.175 m, which is significantly higher than the concentration at which aggregation-induced quenching occurs in other media...
September 18, 2017: Angewandte Chemie
https://www.readbyqxmd.com/read/28921977/photoinduced-bimolecular-electron-transfer-in-ionic-liquids
#3
Boning Wu, Mark Maroncelli, Edward W Castner
The present work seeks to better understand the role of solute diffusion and solvation dynamics on bimolecular electron transfer in ionic liquids (ILs). Steady-state and time-resolved measurements of the reductive fluorescence quenching of five fluorophores ("F") by six quenchers ("Q"; electron donors) are reported in acetonitrile and two ionic liquids, 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)amide and trihexyl(tetradecyl)phosphonium bis(trifluoromethylsulfonyl)amide. Data were collected on 66 different F-Q-solvent systems, which span a 2...
September 18, 2017: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/28920988/fluorogenic-nir-probes-based-on-1-2-4-5-tetrazine-substituted-bf2-azadipyrromethenes
#4
Dan Wu, Donal F O'Shea
A series of 1,2,4,5-tetrazine integrated near infrared (NIR) fluorophores based on the BF2 azadipyrromethene (NIR-AZA) class has been synthesised and their ability to modulate emission from low to high in response to Diels-Alder cycloaditions has been assessed. Substituents on the tetrazine component of the probe (Cl, OMe, p-NO2C6H4O) were seen to strongly influence quantum yields, fluorescence enhancement factors, and rates of cycloadditions. Cycloadditions between tetrazine-NIR-AZA constructs and a strained alkyne substrate were seen to be highly efficient in organic or aqueous solutions and in gels with high fluorescence enhancements of up to 48-fold observed...
September 18, 2017: Chemical Communications: Chem Comm
https://www.readbyqxmd.com/read/28920937/resolving-ultrafast-exciton-migration-in-organic-solids-at-the-nanoscale
#5
Samuel B Penwell, Lucas D S Ginsberg, Rodrigo Noriega, Naomi S Ginsberg
Effectiveness of molecular-based light harvesting relies on transport of excitons to charge-transfer sites. Measuring exciton migration, however, has been challenging because of the mismatch between nanoscale migration lengths and the diffraction limit. Instead of using bulk substrate quenching methods, here we define quenching boundaries all-optically with sub-diffraction resolution, thus characterizing spatiotemporal exciton migration on its native nanometre and picosecond scales. By transforming stimulated emission depletion microscopy into a time-resolved ultrafast approach, we measure a 16-nm migration length in poly(2,5-di(hexyloxy)cyanoterephthalylidene) conjugated polymer films...
September 18, 2017: Nature Materials
https://www.readbyqxmd.com/read/28920855/pfma-a-novel-quorum-quenching-n-acylhomoserine-lactone-acylase-from-pseudoalteromonas-flavipulchra
#6
Na Liu, Min Yu, Youbin Zhao, Jingguang Cheng, Ke An, Xiao-Hua Zhang
Many bacteria, such as Proteobacteria, Cyanobacteria and Bacteroidetes, use N-acylhomoserine lactones (AHLs) as quorum-sensing (QS) signal molecules for communication. Enzymatic degradation of AHLs, such as AHL acylase and AHL lactonase, can degrade AHLs (quorum quenching, QQ) to attenuate or disarm the virulence of pathogens. QQ is confirmed to be common in marine bacterial communities. Many genes encoding AHL acylases are found in marine bacteria and metagenomic collections, but only a few of these have been characterized in detail...
September 18, 2017: Microbiology
https://www.readbyqxmd.com/read/28920667/warm-white-light-emitting-diode-based-on-a-dye-loaded-metal-organic-framework-for-fast-white-light-communication
#7
Zhiye Wang, Zi Wang, Bangjiang Lin, Xuefu Hu, YunFeng Wei, Cankun Zhang, Bing An, Cheng Wang, Wenbin Lin
A dye@metal-organic framework (MOF) hybrid was used as a phosphor in a white light emitting diode (WLED) for fast visible-light communication (VLC). The white light was generated from a combination of blue emission of the 9,10-dibenzoate anthracene (DBA) linkers and yellow emission of the encapsulated Rhodamine B molecules. The MOF structure not only prevents dye molecules from aggregation-induced quenching, but also efficiently transfers energy to the dye for dual emission. This light-emitting material shows emission lifetimes of 1...
September 18, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28920422/dual-activator-codoped-upconversion-nanoprobe-with-core-multishell-structure-for-in-vitro-and-in-vivo-detection-of-hydroxyl-radical
#8
Xin-Yue Song, Jiayu Zhang, Zihong Yue, Zonghua Wang, Zhihong Liu, Shusheng Zhang
Monitoring the fluctuation of hydroxyl radical (•OH) in the body can serve as an effective tool for the prediction of relative diseases, which, however, is highly challenging due to its short lifetime, high reactivity and extremely low concentration. Sandwich structured lanthanide-doped upconversion nanoparticles (UCNPs) exhibit unique luminescence properties and great prospects in bioimaging. Nonetheless, their rather low luminescence efficiency and intensity are serious limitations for their application...
September 18, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28919648/optical-imaging-of-large-gyroid-grains-in-block-copolymer-templates-by-confined-crystallization
#9
Raphael Dehmel, James A Dolan, Yibei Gu, Ulrich Wiesner, Timothy D Wilkinson, Jeremy J Baumberg, Ullrich Steiner, Bodo D Wilts, Ilja Gunkel
Block copolymer (BCP) self-assembly is a promising route to manufacture functional nanomaterials for applications from nanolithography to optical metamaterials. Self-assembled cubic morphologies cannot, however, be conveniently optically characterized in the lab due to their structural isotropy. Here, the aligned crystallization behavior of a semicrystalline-amorphous polyisoprene-b-polystyrene-b-poly(ethylene oxide) (ISO) triblock terpolymer was utilized to visualize the grain structure of the cubic microphase-separated morphology...
August 22, 2017: Macromolecules
https://www.readbyqxmd.com/read/28919529/acetylation-of-lysine-residues-in-apomyoglobin-structural-changes-amyloid-fibrillation-and-role-of-surface-charge
#10
Mehrnaz Azami-Movahed, Ali Akbar Meratan, Atiyeh Ghasemi, Azadeh Ebrahim-Habibi, Mohsen Nemat-Gorgani
Post-translational modifications play important roles in conformational properties and aggregation propensities of different peptides and proteins. In the present study, we have investigated the effects of acetylation of lysine residues on the structure and aggregation properties of apomyoglobin (apoMb).All of the 19 lysine residues were modified. Far-, near-UV CD, intrinsic and acrylamide quenching fluorescence studies indicated that acetylation significantly influences conformation of apoMb by altering both its secondary and tertiary structures...
September 14, 2017: International Journal of Biological Macromolecules
https://www.readbyqxmd.com/read/28918220/synthesis-and-application-of-a-highly-selective-copper-ions-fluorescent-probe-based-on-the-coumarin-group
#11
Guangjie He, Xiangli Liu, Jinhe Xu, Liguo Ji, Linlin Yang, Aiying Fan, Songjun Wang, Qingzhi Wang
A highly selective copper ions fluorescent probe based on the coumarin-type Schiff base derivative 1 (probe) was produced by condensation reaction between coumarin carbohydrazide and 1H-indazole-3-carbaldehyde. The UV-vis spectroscopy showed that the maximum absorption peak of compound 1 appeared at 439nm. In the presence of Cu(2+) ions, the maximum peak decreased remarkably compared with other physiological important metal ions and a new absorption peak at 500nm appeared. The job's plot experiments showed that complexes of 1:2 binding mode were formed in CH3CN:HEPES (3:2, v/v) solution...
September 13, 2017: Spectrochimica Acta. Part A, Molecular and Biomolecular Spectroscopy
https://www.readbyqxmd.com/read/28918077/membrane-electro-oxidizer-a-new-hybrid-membrane-system-with-electrochemical-oxidation-for-enhanced-organics-and-fouling-control
#12
Naresh Mameda, Hyung-June Park, Kwang-Ho Choo
The synergistic combination of membrane filtration with advanced oxidation is of particular interest for next-generation wastewater treatment technologies. A membrane electro-oxidizer (MEO) hybridizing a submerged microfilter and an electrochemical cell was developed and investigated for tertiary treatment of secondary industrial (textile) wastewater effluent. Laboratory- and pilot-scale MEO systems were designed and evaluated for treatment efficiency and membrane fouling control. The MEO achieved substantial removal of color (50-90%), turbidity (>90%), and bacteria (>4 log) as well as chemical oxygen demand (13-31%) and 1,4-dioxane (∼25-53%)...
September 5, 2017: Water Research
https://www.readbyqxmd.com/read/28918054/rapid-and-sensitive-detection-of-breast-cancer-cells-in-patient-blood-with-nuclease-activated-probe-technology
#13
Sven Kruspe, David D Dickey, Kevin T Urak, Giselle N Blanco, Matthew J Miller, Karen C Clark, Elliot Burghardt, Wade R Gutierrez, Sneha D Phadke, Sukriti Kamboj, Timothy Ginader, Brian J Smith, Sarah K Grimm, James Schappet, Howard Ozer, Alexandra Thomas, James O McNamara, Carlos H Chan, Paloma H Giangrande
A challenge for circulating tumor cell (CTC)-based diagnostics is the development of simple and inexpensive methods that reliably detect the diverse cells that make up CTCs. CTC-derived nucleases are one category of proteins that could be exploited to meet this challenge. Advantages of nucleases as CTC biomarkers include: (1) their elevated expression in many cancer cells, including cells implicated in metastasis that have undergone epithelial-to-mesenchymal transition; and (2) their enzymatic activity, which can be exploited for signal amplification in detection methods...
September 15, 2017: Molecular Therapy. Nucleic Acids
https://www.readbyqxmd.com/read/28917845/influence-of-binding-mechanism-on-labeling-efficiency-and-luminous-properties-of-fluorescent-cellulose-nanocrystals
#14
Qijun Ding, Jinsong Zeng, Bin Wang, Wenhua Gao, Kefu Chen, Zhe Yuan, Jun Xu
Cellulose nanocrystals (CNCs) have excellent properties, such as reproducibility, low biodegradability and a large amount of reactive hydroxyl groups on the surface. This study focused on the labeling efficiency and fluorescent properties of the fluorescent labeling of CNCs by means of electrostatic adsorption and covalent bonding. The CNCs in the sample were approximately 94.76% successfully labeled with dyes, and the number of dye molecules adsorbed by per CNC was approximately 208 by electrostatic adsorption...
November 1, 2017: Carbohydrate Polymers
https://www.readbyqxmd.com/read/28917785/fluorescence-quenching-based-alkaline-phosphatase-activity-detection
#15
Yaqi Mei, Qiong Hu, Baojing Zhou, Yonghui Zhang, Minhui He, Ting Xu, Feng Li, Jinming Kong
Simple and fast detection of alkaline phosphatase (ALP) activity is of great importance for diagnostic and analytical applications. In this work, we report a turn-off approach for the real-time detection of ALP activity on the basis of the charge transfer induced fluorescence quenching of the Cu(BCDS)2(2-) (BCDS = bathocuproine disulfonate) probe. Initially, ALP can enzymatically hydrolyze the substrate ascorbic acid 2-phosphate to release ascorbic acid (AA). Subsequently, the AA-mediated reduction of the Cu(BCDS)2(2-) probe, which displays an intense photoluminescence band at the wavelength of 402nm, leads to the static quenching of fluorescence of the probe as a result of charge transfer...
January 1, 2018: Talanta
https://www.readbyqxmd.com/read/28917784/green-synthesis-of-graphitic-carbon-nitride-nanosheet-g-c3n4-and-using-it-as-a-label-free-fluorosensor-for-detection-of-metronidazole-via-quenching-of-the-fluorescence
#16
Amir Hatamie, Farzanh Marahel, Ali Sharifat
In this research, g-C3N4nanosheets were facilely fabricated by thermal polymerization and then exfoliated into ultrathin nanosheets through ultrasonication in water media. Low-cost C-N nanosheets prepared by melamine possessed a highly π-conjugated structure and fluorescence property. In the present study, the g-C3N4nanosheet was used as a switch-off fluorescence sensor for rapid and sensitive sensing of metronidazole in biological fluids. These nanosheets were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), and Fourier transform infrared (FTIR) spectroscopy...
January 1, 2018: Talanta
https://www.readbyqxmd.com/read/28917781/fluorescence-self-quenching-assay-for-the-detection-of-target-collagen-sequences-using-a-short-probe-peptide
#17
Linge Nian, Yue Hu, Caihong Fu, Chen Song, Jie Wang, Jianxi Xiao
The development of novel assays to detect collagen fragments is of utmost importance for diagnostic, prognostic and therapeutic decisions in various collagen-related diseases, and one essential question is to discover probe peptides that can specifically recognize target collagen sequences. Herein we have developed the fluorescence self-quenching assay as a convenient tool to screen the capability of a series of fluorescent probe peptides of variable lengths to bind with target collagen peptides. We have revealed that the targeting ability of probe peptides is length-dependent, and have discovered a relatively short probe peptide FAM-G(POG)8 capable to identify the target peptide...
January 1, 2018: Talanta
https://www.readbyqxmd.com/read/28917774/fret-on-lateral-flow-test-strip-to-enhance-sensitivity-for-detecting-cancer-biomarker
#18
Jidong Wang, Fengjing Cao, Songliang He, Yong Xia, Xinyu Liu, Wenxiao Jiang, Yangyang Yu, Huisheng Zhang, Wenwen Chen
Fluorescence resonance energy transfer (FRET) between fluorescein isothiocyanate (FITC) and gold nanoparticles (Au NPs) is introduced in the lateral flow strip to detect cancer biomarker CEA with the color and fluorescence dual-readout. Anti-CEA monoclonal antibody coated Au NPs were on the conjugate pad and FITC labelled antibody (FITC-Ab) for CEA was coated on the test line. All the reagents were general in the lateral flow strip or commercially available and no new materials or technique were involved, which make our proposal a more universal method and easier to operate...
January 1, 2018: Talanta
https://www.readbyqxmd.com/read/28917502/fluorescence-and-magnetic-nanocomposite-fe3o4-sio2-au-mnps-as-peroxidase-mimetics-for-glucose-detection
#19
Shajie Luo, Yaqin Liu, Hanbing Rao, Yanying Wang, Xianxiang Wang
In this paper, multifunction nanoparticles (MNPs), Fe3O4@SiO2@Au MNPs, with properties of superparamagnetism, fluorescence and peroxidase-like catalytic activity were synthesized in the aqueous phase. The synthesized composites were characterized by scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), powder diffraction (XRD), Fourier translation infrared spectrum (FT-IR) and fluorometer. The results show that the multifunctional nanomaterials have good magnetic and fluorescence properties...
September 13, 2017: Analytical Biochemistry
https://www.readbyqxmd.com/read/28916593/carnosic-acid-and-carnosol-two-major-antioxidants-of-rosemary-act-through-different-mechanisms
#20
Margot Loussouarn, Anja Krieger-Liszkay, Ljubica Svilar, Antoine Bily, Simona Birtic, Michel Havaux
Carnosic acid, a phenolic diterpene specific of the Lamiaceae family, is highly abundant in rosemary species. Despite numerous industrial and medicinal/pharmaceutical applications of its antioxidative features, this compound in planta and its antioxidant mechanism have received little attention, except a few studies of rosemary plants under natural conditions. In vitro analyses, using HPLC-UV and luminescence imaging, revealed that carnosic acid and its major oxidized derivative, carnosol, protect lipids from oxidation...
September 15, 2017: Plant Physiology
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