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https://www.readbyqxmd.com/read/28822320/bio-active-maneonenes-and-isomaneonene-from-the-red-alga-laurencia-obtusa
#1
Nahed O Bawakid, Walied M Alarif, Ali I Ismail, Mohamed E El-Hefnawy, Khalid O Al-Footy, Sultan S Al-Lihaibi
Three previously undescribed compounds, maneonenes and isomaneonene derivatives; in addition to five known compounds, two cuparene, one chamigrene, and two cis-maneonenes were isolated from the Red Sea red alga Laurencia obtusa. The chemical structures of all unknown metabolites were characterized employing spectroscopic methods and then were further confirmed by single crystal X-ray analysis. Jeddahenyne A has C-5-C-12 etheric linkage and C-13-C-14 carbon-carbon double bond; Jeddahenyne B has in addition to the aforementioned etheric linkage a C-13 carbonyl function and absence of halogenation, unusual features for the maneonenes while 12-debromo-12-methoxy isomaneonene A shows unrecorded methoxylation at C-12...
August 16, 2017: Phytochemistry
https://www.readbyqxmd.com/read/28822076/studies-of-the-benzopyran-class-of-selective-cox-2-inhibitors-using-3d-qsar-and-molecular-docking
#2
Dharmendra K Yadav, Saloni, Praveen Sharma, Sanjeev Misra, Harpreet Singh, Ricardo L Mancera, Kang Kim, Cheongyun Jang, Mi-Hyun Kim, Horacio Pérez-Sánchez, Eun Ha Choi, Surendra Kumar
The Gaussian-based 3D-QSAR studies for 58 selective COX-2 (cyclooxygenase-2) inhibitors belonging to benzopyran chemical class were performed. Partial least squares analysis produced statistically significant model with (R training(2)  = 0.866) and predictability (Q training(2)  = 0.66, Q test(2)  = 0.846). The 3D-QSAR model includes steric, electrostatic, hydrophobic, and hydrogen bond acceptor field indicators, whereas the potential field contributions indicate that the steric and hydrophobic features of the molecules play an important role in governing their biological activity...
August 18, 2017: Archives of Pharmacal Research
https://www.readbyqxmd.com/read/28822069/characterization-of-ofloxacin-interaction-with-mutated-a91v-quinolone-resistance-determining-region-of-dna-gyrase-in-mycobacterium-leprae-through-computational-simulation
#3
J Nisha, V Shanthi
Mycobacterium leprae, the causal agent of leprosy is non-cultivable in vitro. Thus, the assessment of antibiotic activity against Mycobacterium leprae depends primarily upon the time-consuming mouse footpad system. The GyrA protein of Mycobacterium leprae is the target of the antimycobacterial drug, Ofloxacin. In recent times, the GyrA mutation (A91V) has been found to be resistant to Ofloxacin. This phenomenon has necessitated the development of new, long-acting antimycobacterial compounds. The underlying mechanism of drug resistance is not completely known...
August 18, 2017: Cell Biochemistry and Biophysics
https://www.readbyqxmd.com/read/28821823/highly-efficient-up-conversion-luminescence-in-er-3-yb-3-co-doped-na5lu9f32-single-crystals-by-vertical-bridgman-method
#4
Shinan He, Haiping Xia, Jianli Zhang, Yongsheng Zhu, Baojiu Chen
Er(3+)/Yb(3+) co-doped Na5Lu9F32 single crystals with different concentrations of Yb(3+) ions were prepared to investigate their phase structure, up-conversion (UC) properties and mechanism of UC luminescence by Bridgman method. Under 980 nm near-infrared (NIR) excitation, three sharp UC emission bands topping at green ~525 nm, ~548 nm and red ~669 nm were obtained in Er(3+)/Yb(3+) doped Na5Lu9F32 single crystals which are attributing to the transitions of (2)H11/2 → (4)I15/2, (4)S3/2 → (4)I15/2 and (4)F9/2 → (4)I15/2, respectively...
August 18, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28821766/protein-composition-analysis-of-polyhedra-matrix-of-bombyx-mori-nucleopolyhedrovirus-bmnpv-showed-powerful-capacity-of-polyhedra-to-encapsulate-foreign-proteins
#5
Zhong-Jian Guo, Meng-Han Yu, Xian-Yun Dong, Wei-Li Wang, Ting Tian, Xian-Yin Yu, Xu-Dong Tang
Polyhedra can encapsulate other proteins and have potential applications as protein stabilizers. The extremely stable polyhedra matrix may provide a platform for future engineered micro-crystal devices. However, the protein composition of the polyhedra matrix remains largely unknown. In this study, the occlusion-derived virus (ODV)-removed BmNPV polyhedra matrix fraction was subjected to SDS-PAGE and then an LC-ESI-MS/MS analysis using a Thermo Scientific Q Exactive mass spectrometer. In total, 28 host and 91 viral proteins were identified...
August 18, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28821723/structural-and-developmental-expression-of-ss-riok-2-an-rio-protein-kinase-encoding-gene-of-strongyloides-stercoralis
#6
Wei-Qiang Lei, James B Lok, Wang Yuan, Yue-Zhou Zhang, Jonathan D Stoltzfus, Robin B Gasser, Si-Yuan He, Huan Zhou, Rui Zhou, Jun-Long Zhao, Min Hu
RIO kinases are essential atypical protein kinases in diverse prokaryotic and eukaryotic organisms, playing significant roles in yeast and humans. However, little is known about their functions in parasitic nematodes. In the present study, we have isolated and characterized the full-length cDNA, gDNA and a putative promoter of a RIOK-2 protein kinase (Ss-RIOK-2) encoding gene (Ss-riok-2) from Strongyloides stercoralis, a medically important parasitic nematode (Order Rhabditida). A three-dimensional structure (3D) model of Ss-RIOK-2 was generated using the Chaetomium thermophilum RIOK-2 protein kinase (Ct-RIOK-2) crystal structure 4GYG as a template...
August 18, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28821720/structural-basis-for-the-broad-substrate-specificity-of-the-human-tyrosylprotein-sulfotransferase-1
#7
Shinnosuke Tanaka, Toshiaki Nishiyori, Hidetaka Kojo, Reo Otsubo, Moe Tsuruta, Katsuhisa Kurogi, Ming-Cheh Liu, Masahito Suiko, Yoichi Sakakibara, Yoshimitsu Kakuta
Tyrosylprotein sulfotransferases (TPSTs) are enzymes that catalyze post-translational tyrosine sulfation of proteins. In humans, there are only two TPST isoforms, designated TPST1 and TPST2. In a previous study, we reported the crystal structure of TPST2, which revealed the catalytic mechanism of the tyrosine sulfation reaction. However, detailed molecular mechanisms underlying how TPSTs catalyse a variety of substrate proteins with different efficiencies and how TPSTs catalyze the sulfation of multiple tyrosine residues in a substrate protein remain unresolved...
August 18, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28821550/crystal-structure-of-the-tetr-family-repressor-alkx-from-dietzia-sp-dq12-45-1b-implicated-in-biodegradation-of-n-alkanes
#8
Jie-Liang Liang, Yuan Gao, Zheng He, Yong Nie, Meng Wang, Jing-Hong JiangYang, Xuejun C Zhang, Wen-Sheng Shu, Xiao-Lei Wu
n-Alkanes are ubiquitous in nature and are widely used by microorganisms as carbon sources. Alkane hydroxylation by alkane monooxygenases is a critical step in the aerobic biodegradation of n-alkanes, which plays important roles in natural alkane attenuation and is used in industrial and environmental applications. The alkane oxidation operon, alkW1-alkX, in an alkane-degrading strain Dietzia sp. DQ12-45-1b, is negatively auto-regulated by the TetR family repressor, AlkX, via a product positive feedback mechanism...
August 18, 2017: Applied and Environmental Microbiology
https://www.readbyqxmd.com/read/28821431/bacillus-thuringiensis-cyt2aa2-binding-on-lipid-cholesterol-bilayer-depends-on-protein-concentration-and-time
#9
Sudarat Tharad, Alberto Moreno-Cencerrado, Öykü Üzülmez, Boonhiang Promdonkoy, Jose L Toca-Herrera
Bacillus thuringiensis is a bacterium known for its bioinsecticide properties. Besides Cry toxins, B. thuringiensis also produces cytolytic proteins (Cyt) that show toxicity against dipteran insect larvae. Two different models have been proposed in order to explain the interaction mechanism of the cytolytic protein Cyt2Aa2 on lipid membranes: pore-forming and detergent-like action. Here we report on the interaction of Cyt2Aa2 with lipid/cholesterol bilayers at early stage as a function of protein concentration...
August 15, 2017: Biochemical and Biophysical Research Communications
https://www.readbyqxmd.com/read/28821151/flexibility-of-backbone-fibrils-in-%C3%AE-chitin-crystals-with-different-degree-of-acetylation
#10
Zechuan Yu, Denvid Lau
Acetyl groups are backbone outreaches that enhance inter-fibril connection in chitin and chitosan fibril bundle. Removal of acetyl groups affects flexibility of chitosan fibril bundle, thereby affecting mechanical strength of chitosan-based products. Understandings of relationship between degree of acetylation and flexibility of chitin fibril bundle conduce to optimization of synthetic chitin materials. Here, the relationship is examined by performing molecular dynamics simulations. Coiling of chitin and chitosan fibril bundle with different degree of acetylation is observed and flexibility of fibrils is measured...
October 15, 2017: Carbohydrate Polymers
https://www.readbyqxmd.com/read/28821101/cholesteric-film-of-cu-ii-doped-cellulose-nanocrystals-for-colorimetric-sensing-of-ammonia-gas
#11
Shidong Dai, Nana Prempeh, Dagang Liu, Yimin Fan, Mingyue Gu, Yu Chang
With the increasing demand of environmental monitoring for toxic and odorous ammonia gas it is desired to develop specific green, cost-effective and in situ passive colorimetric alternatives to current complex instrumentations. In this work, we designed an ammonia gas sensor based on cholesteric liquid crystal films of copper(II)-doped cellulose nanocrystals (CNCCu(II)) whose structure, optical and sensing properties were investigated. The hybrid films using the low doping Cu(II) as a color-tuning agent inherited the chiral nematic signature and optical activity of CNCs, suggesting a strong chelation between copper ions and negatively charged CNCs...
October 15, 2017: Carbohydrate Polymers
https://www.readbyqxmd.com/read/28821084/green-synthesis-of-oriented-xanthan-gum-graphene-oxide-hybrid-aerogels-for-water-purification
#12
Shunli Liu, Fang Yao, Olayinka Oderinde, Zhihong Zhang, Guodong Fu
Three-dimensional xanthan gum (XG)/graphene oxide (GO) hybrid aerogels were fabricated by ice crystal templating without using chemical modifiers. The hybrid aerogels were prepared by the stirring of xanthan gum-graphene oxide hybrid solution, followed by freezing at low temperature and finally by freeze-drying. The whole preparation could be completed within 12h without producing any contamination and thus considered a fast, simple, economical, and green method for aerogel fabrication. XG/GO hybrid aerogels possessed different hierarchical pore structures because of various freezing temperatures...
October 15, 2017: Carbohydrate Polymers
https://www.readbyqxmd.com/read/28821030/preparation-and-characterization-of-a-photocatalytic-antibacterial-material-graphene-oxide-tio2-bacterial-cellulose-nanocomposite
#13
Ling-Pu Liu, Xiao-Ning Yang, Li Ye, Dong-Dong Xue, Miao Liu, Shi-Ru Jia, Ying Hou, Li-Qiang Chu, Cheng Zhong
In this study, bacterial cellulose (BC) was used as a matrix to synthesize graphene oxide/Titanium dioxide (GOTiO2)-based hybrid materials. It was indicated by X-ray diffraction and selected area electron diffraction that the crystal structure of GOTiO2 was a mixed phase containing anatase and rutile. TiO2 nanoparticles were of 10-30nm diameters and densely anchored on graphene oxide sheets. Superior photocatalytic performance of the GOTiO2 was achieved under near UV excitation. The photocatalytic efficiency was optimized through controlling an appropriate calcined temperature...
October 15, 2017: Carbohydrate Polymers
https://www.readbyqxmd.com/read/28820940/polyoxometalate-cationic-cluster-and-%C3%AF-%C3%AE-cyclodextrin-from-primary-interactions-to-supramolecular-hybrid-materials
#14
Mhamad Aly Moussawi, Nathalie Leclerc-Laronze, Sébastien Floquet, Pavel A Abramov, Maxim Nailyevich Sokolov, Stephane Cordier, Anne Ponchel, Eric Monflier, Herve Bricout, David Landy, Mohamed Haouas, Jerome Marrot, Emmanuel Cadot
Herein, we report on a three-component supramolecular hybrid system built from specific recognition processes involving a Dawson type polyoxometalate [P2W18O62](6-,) a cationic electron-rich cluster {[Ta6Br12(H6O)6]@2CD}(2+) and γ-cyclodextrin. Investigations of such a class of materials have been conducted using bottom-up approach by studying the specific interactions between -CD and both types of inorganic units. Their ability to interact has been investigated in the solid state by single-crystal X-ray diffraction and in solution using multinuclear NMR methods (including DOSY, EXSY and COSY), ESI-mass and UV-vis spectroscopies, electrochemistry and ITC experiments...
August 18, 2017: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/28820900/secy-seca-fusion-protein-retains-the-ability-to-mediate-protein-transport
#15
Yasunori Sugano, Arata Furukawa, Osamu Nureki, Yoshiki Tanaka, Tomoya Tsukazaki
In bacteria, the membrane protein complex SecY/E/G and SecA ATPase are essential for protein translocation. About 30% of newly synthesized proteins in the cytosol are targeted to and translocated across the cytoplasmic membrane by the Sec factors. Although a number of single-molecule analyses and structural studies, including the crystal structure of SecYEG complexed with SecA, have been published, the underlying molecular mechanisms and the functional oligomer states remain elusive. In this study, we constructed a fusion protein SecY-SecA, which induces the formation of the SecY-A/SecE/SecG complex (SecYAEG), to enable investigation of the molecular mechanisms by advanced single-molecule analyses...
2017: PloS One
https://www.readbyqxmd.com/read/28820596/processing-solvent-dependent-electronic-and-structural-properties-of-cesium-lead-triiodide-thin-films
#16
Alexandra J Ramadan, Luke A Rochford, Sarah Fearn, Henry J Snaith
Cesium lead triiodide (CsPbI3) is an attractive material for photovoltaic applications due to its appropriate band gap, strong optical absorption and high thermal stability. However, the perovskite phase suffers from moisture induced structural instability. Previous studies have utilized a range of solvent systems to establish the role of solvent choice in structural instabilities. Despite this, effects of different solvents on the electronic structure of this material have not been compared. We report substantial chemical and compositional differences in thin films of CsPbI3 prepared from a range of solvent systems...
August 18, 2017: Journal of Physical Chemistry Letters
https://www.readbyqxmd.com/read/28820255/discovery-of-a-potent-inhibitor-class-with-high-selectivity-towards-clostridial-collagenases
#17
Esther Schönauer, Andreas Martin Kany, Jörg Haupenthal, Kristina Hüsecken, Isabel Josephin Hoppe, Katrin Voos, Samir Yahiaoui, Brigitta Elsässer, Christian Ducho, Hans Brandstetter, Rolf W Hartmann
Secreted virulence factors like bacterial collagenases are conceptually attractive targets for fighting microbial infections. However, previous attempts to develop potent compounds against these metalloproteases failed to achieve selectivity against human metalloproteases such as MMPs. Using an SPR-based screening complemented with enzyme inhibition assays, we discovered an N-aryl mercaptoacetamide-based inhibitor scaffold that showed submicromolar affinities towards collagenase H (ColH) from the human pathogen Clostridium histolyticum...
August 18, 2017: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/28820205/a-comparative-study-of-c2h2-adsorption-properties-in-five-isomeric-copper-based-mofs-based-on-naphthalene-derived-diisophthalates
#18
Fengli Chen, Dongjie Bai, Donghao Jiang, Yao Wang, Yabing He
In this work, five positional isomeric ligands consisting of two peripheral isophthalate moieties attached to the central naphthyl core in different ways, namely, 5,5'-(naphthyl-1,3-diyl) diisophthalate (H4L1), 5,5'-(naphthyl-1,4-diyl) diisophthalate (H4L2), 5,5'-(naphthyl-1,5-diyl) diisophthalate (H4L3), 5,5'-(naphthyl-1,6-diyl) diisophthalate (H4L4) and 5,5'-(naphthyl-2,6-diyl) diisophthalate (H4L5), have been used to generate five copper-based MOF isomers. As revealed by single-crystal X-ray diffraction studies, they adopted two different types of topologies depending on the organic ligands: ssa topology for the MOFs ZJNU-71 and ZJNU-74 based on the ligands H4L1 and H4L4, respectively, and nbo topology for the MOFs ZJNU-72, ZJNU-73 and NOTT-103 derived from the ligands H4L2, H4L3 and H4L5, respectively...
August 18, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
https://www.readbyqxmd.com/read/28819970/chemical-selectivity-at-grain-boundary-dislocations-in-monolayer-mo1-xwxs2-transition-metal-dichalcogenides
#19
Ziqian Wang, Yuhao Shen, Shoucong Ning, Yoshikazu Ito, Pan Liu, Zheng Tang, Takeshi Fujita, Akihiko Hirata, Mingwei Chen
Grain boundaries (GBs) are unavoidable crystal defects in polycrystalline materials and significantly influence their properties. However, the structure and chemistry of GBs in 2D transition metal dichalcogenide alloys have not been well established. Here we report significant chemical selectivity of transition metal atoms at GB dislocation cores in Mo1-xWxS2 monolayers. Different from classical elastic field-driven dislocation segregation in bulk crystals, the chemical selectivity in the 2D crystals originates prominently from variation of atomic coordination numbers at dislocation cores...
August 18, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28819662/chiral-amplification-of-disodium-cromoglycate-chromonics-induced-by-a-codeine-derivative
#20
F Berride, E Troche-Pesqueira, G Feio, E J Cabrita, T Sierra, A Navarro-Vázquez, M M Cid
Chromonic liquid crystals (CLC) are lyotropic phases formed by discotic mesogens in water. Simple chiral dopants such as amino acids have been reported to turn chromonic liquid crystals into their cholesteric counterparts. Here we report a chirality amplification effect in the nematic phase of a 9 wt% disodium cromoglycate (DSCG) lyotropic liquid crystal (LLC) upon doping with a water-soluble codeine derivative. The transition on cooling the isotropic to the nematic phase showed the presence of homochiral spindle-shaped droplets (tactoids)...
August 18, 2017: Soft Matter
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