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https://www.readbyqxmd.com/read/29165865/mimicking-class-ib-mn2-ribonucleotide-reductase-a-mnii2-complex-and-its-reaction-with-superoxide
#1
Adriana Magherusan, Ang Zhou, Erik Farquhar, Max Garcia Melchor, Brendan Twamley, Lawrence Que, Aidan Richard McDonald
Class Ib RNRs require superoxide anion (O2*-), rather than dioxygen (O2), to access a high-valent Mn2 oxidant. Complex 1 ([Mn2(O2CCH3)(N-Et-HPTB)](ClO4)2, N-Et-HPTB = N,N,N',N'-tetrakis(2-(1-ethylbenzimidazolyl))-2-hydroxy-1,3-diaminopropane) was synthesised in high yield (90%). 1 was reacted with O2*- at -40 °C resulting in the formation of a metastable species (2). 2 displayed electronic absorption features (λmax = 460, 610 nm) typical of a Mn-peroxide species, and a 29 line EPR signal typical of a MnIIMnIII entity...
November 22, 2017: Angewandte Chemie
https://www.readbyqxmd.com/read/29164821/cytotoxic-triterpenoids-from-roots-of-actinidia-chinensis
#2
Liu-Bin Wei, Si-Yuan Ma, Hong-Xing Liu, Chu-Sheng Huang, Na Liao
Phytochmical investigation of roots of Actinidia chinensis PLANCH led to the isolation triterpenoids 1 - 16, including a new compound 2α,3α,23,24-tetrahydroxyurs-12,20(30)-dien-28-oic acid (1). Their structures were identified on the basis of spectroscopic analysis, including 1D- and 2D-NMR, HR-ESI mass spectrometry, and by comparison with the literatures. The cytotoxicities of triterpenoids 1 - 16 against a panel of cultured human cancer cell lines (HepG2, A549, MCF-7, SK-OV-3, and HeLa) were evaluated. The new compound 1 exhibited moderate antitumor activities with IC50 values of 19...
November 21, 2017: Chemistry & Biodiversity
https://www.readbyqxmd.com/read/29164282/analysis-of-bronopol-2-bromo-2-nitropropan-1-3-diol-residues-in-rice-oryza-sativa-l-by-spe-using-bond-elut-plexa-and-liquid-chromatography-tandem-mass-spectrometry
#3
Shuang-Shuang Chai, Mei-Ling Qin, You-Ning Ma, Huan-Huan Gao, Qiao He, Han-Tong Zhang
A novel method has been developed for the direct, sensitive, and rapid detection of bronopol in rice using a simple solid-phase extraction (SPE) procedure followed by liquid chromatography-tandem mass spectrometry (LC-MS/MS), with electrospray ionization (ESI). Bronopol was stable under acidic conditions, and an acidic environment was thus needed before sample loading to ensure the stability of bronopol. Rice extracts containing bronopol were pretreated using a hydrophilic-lipophilic balanced (Bond Elut Plexa) cartridge to reduce the matrix effect...
November 21, 2017: Analytical and Bioanalytical Chemistry
https://www.readbyqxmd.com/read/29161816/a-rapid-and-efficient-desulfonation-method-for-the-analysis-of-glucosinolates-by-high-resolution-liquid-chromatography-coupled-with-quadrupole-time-of-flight-mass-spectrometry
#4
Jashbir Singh, Guddadarangavvanahal Jayaprakasha, Bhimanagouda S Patil
The goal of our present research was to develop a simple and rapid method for the quantitation of desulfoglucosinolates (desulfoGLS) without using column chromatography. The proposed method involves extraction, concentration, incubation of glucosinolates with sulfatase enzyme, and HPLC analysis. Identification of desulfoGLS in green kohlrabi was performed by LC-HR-ESI-QTOF-MS in positive ionization mode. A total 11 desulfoGLS were identified with neoglucobrassicin (3.32±0.05 µmol/g DW) as the predominant indolyl, whereas progoitrin and sinigrin were the major aliphatic desulfoGLS...
November 22, 2017: Journal of Agricultural and Food Chemistry
https://www.readbyqxmd.com/read/29161811/coordination-structure-and-fragmentation-chemistry-of-the-tripositive-lanthanide-thio-diglycolamide-complexes
#5
Xiuting Chen, Qingnuan Li, Yu Gong
Tripositive Ln(TMTDA)33+ complexes (Ln = La-Lu except Pm, TMTDA= tetramethyl 3-thio-diglycolamide) were observed in the gas phase by electrospray ionization (ESI) of LnCl3 and TMTDA mixtures. Collision induced dissociation (CID) was employed to investigate their fragmentation chemistry, which revealed the influence of metal center as well as ligand on the ligated complexes. Ln(TMTDA)2(TMTDA-45)3+ resulting from Ccarbonyl-N bond cleavage of TMTDA and hydrogen transfer was the major CID product for all Ln(TMTDA)33+ except Eu(TMTDA)33+ which predominantly formed charge reducing product EuII(TMTDA)22+ via electron transfer from TMTDA to Eu3+...
November 22, 2017: Journal of Physical Chemistry. A
https://www.readbyqxmd.com/read/29161005/esi-ms-for-microsized-bioparticles
#6
Abdil Ozdemir, Jung-Lee Lin, Mustafa Gulfen, Szu-Hsueh Lai, Chun-Jen Hsiao, Nelson Gee-Con Chen, Chung-Hsuan Chen
An ESI ion trap mass spectrometer was designed for high throughput and rapid mass analysis of large bio-particles. Mass calibration of the instrument was performed using commercially available polystyrene micro-particles, and the selected sizes of the polystyrene (PS) particles were approximately 3 to 15 µm, which is consistent with the size of the cancer cells selected for this work. It provides the analysis of micro-sized inorganic and bioparticles. Different sizes of MCF-7 breast cancer cells (8 to 15 µm) were used in this study...
November 21, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/29160873/low-oxidation-state-silicon-clusters-synthesis-and-structure-of-nhc-dipp-cu-%C3%AE-4-si9-3
#7
Felix S Geitner, Thomas F Fässler
The reaction of NHC(Dipp)CuCl with the silicide phases A12Si17 (A: K, K/Rb, Rb) in NH3(l) yields [NHC(Dipp)Cu(η(4)-Si9)](3-) (1) as only the third example of a substituted [Si9] cluster. The corresponding salts A3[A(2.2.2-crypt)]3[NHC(Dipp)Cu(η(4)-Si9)]2·26NH3 (A: K (1a), K/Rb (1b), Rb (1c)) crystallize isostructurally in the space group P1[combining macron] and have been characterized by single crystal structure determination. ESI-MS and NMR experiments reveal that the anion [NHC(Dipp)Cu(η(4)-Si9)](3-) can also be transferred to pyridine or acetonitrile solutions at low temperature...
November 21, 2017: Chemical Communications: Chem Comm
https://www.readbyqxmd.com/read/29160111/new-cytotoxic-sesquiterpene-lactones-from-achillea-cretica-l-growing-in-tunisia
#8
Fayçal Hichri, Mansour Znati, Jalloul Bouajila, Hichem Ben Jannet
The phytochemical study of Achillea cretica growing in Tunisia led to the isolation of two novel sesquiterpene lactones, which have been designated achicretin 1 and achicretin 2. Their chemical structures were further confirmed by mass spectroscopy (ESI-MS) and by extensive application of one- and two-dimensional NMR spectroscopy. The isolated compounds were tested for their cytotoxic activity against four human cancer cell lines, IGROV-1, OVCAR-3, MCF-7, and HCT-116 using the MTT assay. It has been found that achicretin 2 exhibited more potent inhibitory activity with IC50 = values of 14...
November 21, 2017: Journal of Asian Natural Products Research
https://www.readbyqxmd.com/read/29159333/new-phenazine-based-aie-probes-for-selective-detection-of-aluminium-iii-ions-in-presence-of-other-trivalent-metal-ions-in-living-cells
#9
Gopal Balamurugan, Sivan Velmathi, Natesan Thirumalaivasan, Shu Pao Wu
Phenazine fluorophore based imidazole derivatives (S1 and S2) were synthesized and sensor studies were carried out with various cations. Aggregation induced emission (AIE) was observed selectively for Al(3+) among other cations under study in case of both sensors. (1)H NMR titration supported the aggregation induced emission of S2 with Al(3+). ESI mass spectra successfully confirmed the aggregate formation. SEM images clearly showed the aggregation of receptor induced by Al(3+) in a flower-like fashion. AIE probe was successfully applied for bio-imaging of RAW264...
November 21, 2017: Analyst
https://www.readbyqxmd.com/read/29158700/x-ray-crystallographic-and-validated-hptlc-analysis-of-the-biomarker-chromone-glucoside-schumanniofioside-a-isolated-from-acalypha-fruticosa-growing-in-saudi-arabia
#10
Areej M Al-Taweel, Ghada A Fawzy, Shagufta Perveen, Perwez Alam, Ali A El Gamal
A chromone glucoside 2-methyl-5,7-dihydroxychromone 5-O-β-D-glucopyranoside (schumanniofioside A, compound 1) was isolated from the methanol extract of Acalypha fruticosa. The structure of compound 1 was fully assigned based on nuclear magnetic resonance (NMR) ((1)H, (13)C and 2D) spectra and electrospray ionization mass spectrum (ESI-MS) in addition to X-ray Crystallography. The molecules were packed in the crystal structure by eight intermolecular O-H⋯O and C-H⋯O interactions. The structure of compound 1 belongs to monoclinic, P21, a = 9...
November 2017: Saudi Pharmaceutical Journal: SPJ: the Official Publication of the Saudi Pharmaceutical Society
https://www.readbyqxmd.com/read/29157818/biological-characteristics-bioactive-components-and-antineoplastic-properties-of-sporoderm-broken-spores-from-wild-cordyceps-cicadae
#11
Yanfang Sun, Michael Wink, Pan Wang, Hongfei Lu, Hongxin Zhao, Hongtao Liu, Shixian Wang, Yang Sun, Zongsuo Liang
BACKGROUND: Cordyceps cicadae, an entomogenous fungus has been used as a dietary therapeutic in traditional Chinese medicine for several millennia, in the form of powders and decoction. However, wild C. cicadae is notably scarce. To date, there is still a lack of comprehensive and deep studies on the biological characteristics, chemical profiles and antineoplastic mechanisms of C. cicadae, especially its spores. AIM OF THE STUDY: This study aimed to identify wild C...
December 1, 2017: Phytomedicine: International Journal of Phytotherapy and Phytopharmacology
https://www.readbyqxmd.com/read/29157813/anti-inflammatory-and-antiviral-activities-of-cynanversicoside-a-and-cynanversicoside-c-isolated-from-cynanchun-paniculatum-in-influenza-a-virus-infected-mice-pulmonary-microvascular-endothelial-cells
#12
Panying Wei, Tao Zhang, Hong Dong, Qiaohong Chen, Xiang Mu, Ge Hu
BACKGROUND: Outbreaks of the influenza A virus (IAV) often occur in various avian and mammalian species, including humans, causing serious respiratory injury worldwide. Therapeutic actions are limited to vaccines and a few antiviral drugs. Combination antiviral compounds and anti-inflammatory modulators to control the propagation of viruses would be more efficient therapeutic strategies for infectious diseases. PURPOSE: This study was designed to isolate anti-inflammatory and antiviral compounds from Cynanchun paniculatum and elucidate their potential molecular mechanisms...
December 1, 2017: Phytomedicine: International Journal of Phytotherapy and Phytopharmacology
https://www.readbyqxmd.com/read/29157810/camptothecin-producing-endophytic-bacteria-from-pyrenacantha-volubilis-hook-icacinaceae-a-possible-role-of-a-plasmid-in-the-production-of-camptothecin
#13
K N Soujanya, R Siva, P Mohana Kumara, Amitava Srimany, G Ravikanth, F A Mulani, T Aarthy, H V Thulasiram, T R Santhoshkumar, Karaba N Nataraja, R Uma Shaanker
BACKGROUND: Camptothecin (CPT), a quinoline alkaloid, is a potent inhibitor of eukaryotic topoisomerase I. Because of this property, several derivatives of CPT are used as chemotherapeutic agents. CPT is produced by several plant species belonging to the Asterid clade as well as by a number of endophytic fungal associates of these plants. In this study, we report the production of CPT by four bacterial endophytes and show the possible role of a plasmid in the biosynthesis of CPT. METHODS: Endophytic bacteria were isolated from leaves, stems and fruits of Pyrenacantha volubilis Hook...
December 1, 2017: Phytomedicine: International Journal of Phytotherapy and Phytopharmacology
https://www.readbyqxmd.com/read/29156586/in-depth-glyco-peptidomics-approach-reveals-unexpected-diversity-of-glycosylated-peptides-and-atypical-post-translational-modifications-in-dendroaspis-angusticeps-snake-venom
#14
Michel Degueldre, Julien Echterbille, Nicolas Smargiasso, Christian Damblon, Charlotte Gouin, Gilles Mourier, Nicolas Gilles, Edwin De Pauw, Loïc Quinton
Animal venoms represent a valuable source of bioactive peptides that can be derived into useful pharmacological tools, or even innovative drugs. In this way, the venom of Dendroaspis angusticeps (DA), the Eastern Green Mamba, has been intensively studied during recent years. It mainly contains hundreds of large toxins from 6 to 9 kDa, each displaying several disulfide bridges. These toxins are the main target of venom-based studies due to their valuable activities obtained by selectively targeting membrane receptors, such as ion channels or G-protein coupled receptors...
November 18, 2017: International Journal of Molecular Sciences
https://www.readbyqxmd.com/read/29156351/benzamide-porphyrins-with-directly-conjugated-and-distal-pyridyl-or-pyridinium-groups-substituted-to-the-porphyrin-macrocycles-study-of-the-photosensitising-abilities-as-inducers-of-apoptosis-in-cancer-cells-under-photodynamic-conditions
#15
Devashish Sengupta, Zeaul Hoque Mazumdar, Avinaba Mukherjee, Debdulal Sharma, Amit Kumar Halder, Samita Basu, Tarun Jha
Amphiphilic porphyrin photosensitisers (PSs) having combinations of directly substituted pyridyl group(s) at the meso-position of a porphyrin macrocycle, and/or indirectly linked pyridyl groups as benzamide derivatives are reported. The compounds 5,10,15,20-tetrakis-(4-pyridylbenzamide)porphyrin (A.2), 5,10,15,20-tetra[N-(pyridine-4-yl)benzamidium] porphyrin (A.3), 5-mono-(4-pyridyl)-10,15,20-tris-(4-pyridylbenzamide)porphyrin (B.2) and 5-mono-(4-methylpyridinium)-10,15,20-tris-(4-pyridiniumbenzamide)porphyrin (B...
November 13, 2017: Journal of Photochemistry and Photobiology. B, Biology
https://www.readbyqxmd.com/read/29155717/synthesis-of-high-purity-nonsymmetric-dialkylphosphinic-acid-extractants
#16
Junlian Wang, Meiying Xie, Xinyu Liu, Shengming Xu
We present the synthesis of (2,3-dimethylbutyl)(2,4,4'-trimethylpentyl)phosphinic acid as an example to demonstrate a method for the synthesis of high purity nonsymmetric dialkylphosphinic acid extractants. Low toxic sodium hypophosphite was chosen as the phosphorus source to react with olefin A (2,3-dimethyl-1-butene) to generate a monoalkylphosphinic acid intermediate. Amantadine was adopted to remove the dialkylphosphinic acid byproduct, as only the monoalkylphosphinic acid can react with amantadine to form an amantadine∙mono-alkylphosphinic acid salt, while the dialkylphosphinic acid cannot react with amantadine due to its large steric hindrance...
October 19, 2017: Journal of Visualized Experiments: JoVE
https://www.readbyqxmd.com/read/29155553/thiyl-radical-based-charge-tagging-enables-sterol-quantitation-via-mass-spectrometry
#17
Sarju Adhikari, Yu Xia
Inspired by the high reactivity and specificity of thiyl radicals toward alkenes, we have developed a new charge derivatization method to enable fast and quantitative analysis of sterols via electrospray ionization-mass spectrometry (ESI-MS). Thioglycolic acid (TGA), a commercially available compound, has been established as a highly efficient tagging reagent. Initiated from photochemical reactions, the thiyl radical derived from TGA abstracts an allylic hydrogen in the B ring of sterols, forming a radical intermediate which rapidly recombines with a second thiyl radical to produce the final tagged product...
November 22, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/29155199/physiochemical-and-functional-properties-of-tiger-puffer-takifugu-rubripes-skin-gelatin-as-affected-by-extraction-conditions
#18
Jinfeng Pan, Qi Li, Hui Jia, Lining Xia, Wengang Jin, Meijun Shang, Chang Xu, Xiuping Dong
The study investigated physiochemical and functional properties of gelatins from tiger puffer skin (GTPS) extracted with warm-water method at 45, 55 and 65°C for 3, 6 and 12h. GTPS45 exhibited strong γ-, β-, α1- and α2-chains, but they faded with the presence of fragments (<80 KDa) in other GTPS. As the increase of temperature and time, amide I and A were shifted to higher wavenumber and their amplitudes in GTPS65-12 decreased. Lightness declined while redness and yellowness were enhanced. Gel strength was in a range of 144...
November 16, 2017: International Journal of Biological Macromolecules
https://www.readbyqxmd.com/read/29154539/electrokinetic-removal-of-dodecyl-sulfate-micelles-from-digested-protein-samples-prior-to-electrospray-ionization-mass-spectrometry
#19
Ria Marni Tubaon, Paul Raymond Haddad, Joselito P Quirino
In proteomics, dodecyl sulfate (DS-) as sodium salt is commonly used in protein solubilization prior to tryptic digestion, but the presence of the DS- hampers the electrospray ionization mass spectrometric (ESI-MS) analysis. The development of DS- depletion techniques is therefore important especially when dealing with small samples where there could be poor sensitivity due to sample loss or dilution during sample preparation. Here, we present a simple and fast electrokinetic removal method of DS- from small volumes of peptide and digested protein samples prior to ESI-MS...
November 20, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/29154014/evaluation-of-sample-extracting-methods-of-fcsm-by-lactobacillus-acidophilus-based-on-a-uplc-q-tof-ms-global-metabolomics-analysis
#20
Yongqiang Wang, Wenju Zhang, Cunxi Nie, Cheng Chen, Xiaoyang Zhang, Jianhe Hu
The study of metabolomics requires extracting as many metabolites as possible from a biological sample. This study aimed to determine the optimal method for the extraction of metabolites from solid-state fermented cottonseed meal (FCSM). The UPLC-Q-TOF-MS global metabolomics technology was used to detect the metabolites in FCSM, and the extraction quantity and extraction efficiency of seven different extraction methods, specifically the WA, 50MeOH, 50MeOHB, 50MeCNB, 80MeOHB, 80MeOH and AMF methods were evaluated...
October 31, 2017: Brazilian Journal of Microbiology: [publication of the Brazilian Society for Microbiology]
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