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https://www.readbyqxmd.com/read/29775879/catalytic-degradation-of-organophosphorous-nerve-agent-simulants-by-polymer-beads-graphene-oxide-with-organophosphorus-hydrolase-like-activity-based-on-rational-design-of-functional-bimetallic-nuclear-ligand
#1
Xuejuan Ma, Lin Zhang, Mengfan Xia, Xiaohong Zhang, Yaodong Zhang
The degradation of organophosphorous nerve agents is of primary concern due to the severe toxicity of these agents. Based on the active center of organophosphorus hydrolase (OPH), a bimetallic nuclear ligand, (5-vinyl-1,3-phenylene)bis(di(1H-imidazol-2-yl) methanol) (VPIM), was designed and synthesized, which contains four imidazole groups to mimic the four histidines at OPH active center. By grafting VPIM on graphene oxide (GO) surface via polymerization, the VPIM-polymer beads@GO was produced. The obtained OPH mimics has an impressive activity in dephosphorylation reactions (turnover frequency (TOF) towards paraoxon: 2...
May 15, 2018: Journal of Hazardous Materials
https://www.readbyqxmd.com/read/29775857/enzyme-free-homogeneous-electrochemical-biosensor-for-dna-assay-using-toehold-triggered-strand-displacement-reaction-coupled-with-host-guest-recognition-of-fe-3-o-4-sio-2-%C3%AE-cd-nanocomposites
#2
Jingjing Jiang, Xinyi Lin, Dong Ding, Guowang Diao
Taking advantages of the toehold-triggered strand displacement reaction (TSDR) and host-guest interaction of β-cyclodextrin (β-CD), a facile enzyme-free and homogeneous electrochemical sensing strategy was designed for the sensitive assay of target DNA using Fe3 O4 @SiO2 @β-CD nanocomposites and ferrocene-labeled hairpin DNA (H-1) as the capture and electrochemical probes, respectively. Upon addition of target molecule, the initiated TSDR process induced the conformational change of H-1, and subsequently stimulated the dynamic assembly of assist probes (A-1 and A-2) to generate H-1:A-1:A-2 duplex along with the release of target sequence...
April 17, 2018: Biosensors & Bioelectronics
https://www.readbyqxmd.com/read/29775713/enhancement-of-catalytic-activity-and-thermostability-of-a-thermostable-cellobiohydrolase-from-chaetomium-thermophilum-by-site-directed-mutagenesis
#3
Chao Han, Weiguang Li, Chengyao Hua, Fengqing Sun, Pengsheng Bi, Qunqing Wang
Enzymatic saccharification of lignocellulosic biomass is increasingly applied in agricultural and industrial applications. Nevertheless, low performance in the extreme environment severely prevents the utilization of commercial enzyme preparations. To obtain cellobiohydrolases with improved catalytic activity and thermostability, structure-based rational design was performed based on a thermostable cellobiohydrolase CtCel6 from Chaetomium thermophilum. In the present study, four conserved and noncatalytic residue substitutions were generated via site-directed mutagenesis...
May 15, 2018: International Journal of Biological Macromolecules
https://www.readbyqxmd.com/read/29775653/atomic-structure-of-a-rationally-engineered-gene-delivery-vector-aav2-5
#4
Matthew Burg, Claire Rosebrough, Lauren M Drouin, Antonette Bennett, Mario Mietzsch, Paul Chipman, Robert McKenna, Duncan Sousa, Mark Potter, Barry Byrne, R Jude Samulski, Mavis Agbandje-McKenna
AAV2.5 represents the first structure-guided in-silico designed Adeno-associated virus (AAV) gene delivery vector. This engineered vector combined the receptor attachment properties of AAV serotype 2 (AAV2) with the muscle tropic properties of AAV1, and exhibited an antibody escape phenotype because of a modified antigenic epitope. To confirm the design, the structure of the vector was determined to a resolution of 2.78 Å using cryo-electron microscopy and image reconstruction. The structure of the major viral protein (VP), VP3, was ordered from residue 219 to 736, as reported for other AAV structures, and the five AAV2...
May 15, 2018: Journal of Structural Biology
https://www.readbyqxmd.com/read/29775652/advances-and-prospects-of-bacillus-subtilis-cellular-factories-from-rational-design-to-industrial-applications
#5
REVIEW
Yang Gu, Xianhao Xu, Yaokang Wu, Tengfei Niu, Yanfeng Liu, Jianghua Li, Guocheng Du, Long Liu
Bacillus subtilis is the most characterized gram-positive bacterium that has significant attributes, such as growing well on cheap carbon sources, possessing clear inherited backgrounds, having mature genetic manipulation methods, and exhibiting robustness in large-scale fermentations. Till date, B. subtilis has been identified as attractive hosts for the production of recombinant proteins and chemicals. By applying various systems and synthetic biology tools, the productivity features of B. subtilis can be thoroughly analyzed and further optimized via metabolic engineering...
May 15, 2018: Metabolic Engineering
https://www.readbyqxmd.com/read/29775221/reagent-induced-asymmetric-induction-in-addition-reaction-of-reduced-glutathione-onto-bis-mannich-chalcones
#6
Aline Bernardes, Giulio D C D'Oliveira, Aneta Silezin, Mónika Kuzma, Szilárd Molnár, Caridad Noda Pérez, Pál Perjési
The stereochemistry of non-enzyme catalyzed nucleophilic addition of GSH to 4'-hydroxychalcone 1 and its bis-Mannich derivative 2 was investigated at different pH values (pH 3.2, 6.1, 7.4, and 8.0). The stereochemical outcome of the reactions was evaluated by HPLC-UV-Vis method. Under strongly acidic conditions (pH 3.2), an unexpected diastereoselective addition of GSH onto the bis-Mannich derivative 2 was observed. Such a selectivity could not be observed in the similar reaction of 2 with N-acetylcysteine...
May 18, 2018: Archiv der Pharmazie
https://www.readbyqxmd.com/read/29775043/designing-a-dy-2-single-molecule-magnet-with-two-well-differentiated-relaxation-processes-by-using-a-nonsymmetric-bis-bidentate-bipyrimidine-n-oxide-ligand-a-comparison-with-mononuclear-counterparts
#7
Ismael F Díaz-Ortega, Juan Manuel Herrera, Daniel Aravena, Eliseo Ruiz, Tulika Gupta, Gopalan Rajaraman, H Nojiri, Enrique Colacio
Herein we report a dinuclear [(μ-mbpymNO){(tmh)3 Dy}2 ] (1) single-molecule magnet (SMM) showing two nonequivalent DyIII centers, which was rationally prepared from the reaction of Dy(tmh)3 moieties (tmh = 2,2,6,6-tetramethyl-3,5-heptanedionate) and the asymmetric bis-bidentate bridging ligand 4-methylbipyrimidine (mbpymNO). Depending on whether the DyIII ions coordinate to the N^O or N^N bidentate donor sets, the DyIII sites present a NO7 ( D2 d geometry) or N2 O6 ( D4 d ) coordination sphere. As a consequence, two different thermally activated magnetic relaxation processes are observed with anisotropy barriers of 47...
May 18, 2018: Inorganic Chemistry
https://www.readbyqxmd.com/read/29774973/aromaticity-and-antiaromaticity-in-zintl-clusters
#8
Zhong-Ming Sun, Chao Liu, Ivan A Popov, Alexander Boldyrev, Zhongfang Chen
Originally, the concepts of aromaticity and antiaromaticity were introduced to explain the stability and reactivity of unsaturated organic compounds. Since then, they have been extended to other species with delocalized electrons including various saturated systems, organometallic compounds, and even inorganic clusters and molecules. In this review, we focus on the most recent progress of using these concepts to guide experimental synthesis and rationalize geometrical and electronic structures of a particular family of polyanions composed of Group 14 and 15 elements, namely Zintl clusters...
May 18, 2018: Chemistry: a European Journal
https://www.readbyqxmd.com/read/29774895/rational-design-of-a-neutral-ph-functional-and-stable-organic-photocathode
#9
Laia Francàs, Eric Burns, Ludmilla Steier, Hyojung Cha, Lluís Solà-Hernández, Xiaoe Li, Pabitra Shakya Tuladhar, Roger Bofill, Jordi García-Antón, Xavier Sala, James R Durrant
In this work we lay out design guidelines for catalytically more efficient organic photocathodes achieving stable hydrogen production in neutral pH. We propose an organic photocathode architecture employing a NiO hole selective layer, a PCDTBT:PCBM bulk heterojunction, a compact TiO2 electron selective contact and a RuO2 nanoparticle catalyst. The role of each layer is discussed in terms of durability and function. With this strategically designed organic photocathode we obtain stable photocurrent densities for over 5 h and discuss routes for further performance improvement...
May 18, 2018: Chemical Communications: Chem Comm
https://www.readbyqxmd.com/read/29774819/midurethral-slings
#10
Joao P Zambon, Catherine Ann Matthews, Gopal H Badlani
Urinary incontinence (UI) is a common symptom affecting almost one-third of adult women. UI can occur because of hypermobility or intrinsic sphincter deficiency of the urethra. Regardless its etiology, it is associated with poor quality of life and most of the incontinent women develop symptoms such as anxiety, depression, and social isolation over time. The synthetic midurethral sling (MUS) was first introduced in 1995 and quickly became the gold standard treatment for women with stress UI because of intrinsic sphincter deficiency and/or urethral hypermobility...
May 2018: Journal of Endourology
https://www.readbyqxmd.com/read/29774742/dual-role-of-water-in-heterogeneous-catalytic-hydrolysis-of-sarin-by-zirconium-based-metal-organic-frameworks
#11
Mohammad R Momeni, Christopher J Cramer
Recent experimental studies on ZrIV-based metal-organic frameworks (MOFs) have shown the extraordinary effective-ness of these porous materials for the detoxification of phos-phorus-based chemical warfare agents (CWAs). However, pressing challenges remain with respect to characterizing these catalytic processes both at the molecular and crystalline lev-els. We here use theory to compare the reactivity of different zirconium-based MOFs for the catalytic hydrolysis of the CWA sarin, using both periodic and cluster modeling...
May 18, 2018: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/29774603/programmed-nanoparticle-loaded-nanoparticles-for-deep-penetrating-3d-cancer-therapy
#12
Jinhwan Kim, Changshin Jo, Won-Gwang Lim, Sungjin Jung, Yeong Mi Lee, Jun Lim, Haeshin Lee, Jinwoo Lee, Won Jong Kim
Tumors are 3D, composed of cellular agglomerations and blood vessels. Therapies involving nanoparticles utilize specific accumulations due to the leaky vascular structures. However, systemically injected nanoparticles are mostly uptaken by cells located on the surfaces of cancer tissues, lacking deep penetration into the core cancer regions. Herein, an unprecedented strategy, described as injecting "nanoparticle-loaded nanoparticles" to address the long-lasting problem is reported for effective surface-to-core drug delivery in entire 3D tumors...
May 18, 2018: Advanced Materials
https://www.readbyqxmd.com/read/29774332/tuning-the-molecular-weight-of-polymeric-amphiphiles-as-a-tool-to-access-micelles-with-a-wide-range-of-enzymatic-degradation-rates
#13
Gadi Slor, Nitsan Papo, Uri Hananel, Roey J Amir
Enyzme-responsive polymeric assemblies hold great potential for biomedical applications due to the over-expression of disease-associated enzymes, which can be utilized to activate such systems only in afflicted tissues. Herein we demonstrate that the overall molecular weight of polymeric amphiphiles, which have the same hydrophilic/hydrophobic ratio, can be tuned to create polymeric micelles with an extreme range of degradation rates. This approach expands the available set of molecular parameters that can be adjusted to tune the degradation rate of polymeric assemblies, paving new possibilities for rational design of polymeric systems with controlled degradation rates...
May 18, 2018: Chemical Communications: Chem Comm
https://www.readbyqxmd.com/read/29774078/targeting-intracellular-mmps-efficiently-inhibits-tumor-metastasis-and-angiogenesis
#14
Yaqi Lv, Xiangmei Zhao, Lidan Zhu, Sijia Li, Qingqing Xiao, Wei He, Lifang Yin
Treatment for metastatic cancer is a great challenge throughout the world. Commonly, directed inhibition of extracellular matrix metalloproteinases (MMPs) secreted by cancer cells can reduce metastasis. Here, a novel nanoplatform (HPMC NPs) assembled from hyaluronic acid (HA)-paclitaxel (PTX) prodrug and marimastat (MATT)/β-casein (CN) complexes was established to cure a 4T1 metastatic cancer model via targeting CD44 and intracellular, rather than extracellular, MMPs. Methods: HPMC NPs were prepared by assembling the complexes and prodrug under ultrasonic treatment, which the interaction between them was evaluated by förster resonance energy transfer, circular dichroism and fluorescence spectra...
2018: Theranostics
https://www.readbyqxmd.com/read/29774065/catalytic-hairpin-assembly-gel-assay-for-multiple-and-sensitive-microrna-detection
#15
Wenhao Dai, Jing Zhang, Xiangdan Meng, Jie He, Kai Zhang, Yu Cao, Dongdong Wang, Haifeng Dong, Xueji Zhang
As important modulators of gene expression, microRNAs (miRNAs) have been identified as promising biomarkers with powerful predictive value in diagnosis and prognosis for several diseases, especially for cancers. Here we report a facile, multiple and sensitive miRNA detection method that uses conventional gel electrophoresis and catalytic hairpin assembly (CHA) system without any complex nanomaterials or enzymatic amplification. Methods: In this study, three pairs of hairpin probes are rationally designed with thermodynamically and kinetically preferable feasibility for the CHA process...
2018: Theranostics
https://www.readbyqxmd.com/read/29774024/quantification-of-hla-dm-dependent-major-histocompatibility-complex-of-class-ii-immunopeptidomes-by-the-peptide-landscape-antigenic-epitope-alignment-utility
#16
Miguel Álvaro-Benito, Eliot Morrison, Esam T Abualrous, Benno Kuropka, Christian Freund
The major histocompatibility complex of class II (MHCII) immunopeptidome represents the repertoire of antigenic peptides with the potential to activate CD4+ T cells. An understanding of how the relative abundance of specific antigenic epitopes affects the outcome of T cell responses is an important aspect of adaptive immunity and offers a venue to more rationally tailor T cell activation in the context of disease. Recent advances in mass spectrometric instrumentation, computational power, labeling strategies, and software analysis have enabled an increasing number of stratified studies on HLA ligandomes, in the context of both basic and translational research...
2018: Frontiers in Immunology
https://www.readbyqxmd.com/read/29773873/therapeutic-nanoparticles-penetrate-leaves-and-deliver-nutrients-to-agricultural-crops
#17
Avishai Karny, Assaf Zinger, Ashima Kajal, Janna Shainsky-Roitman, Avi Schroeder
As the world population grows, there is a need for efficient agricultural technologies to provide global food requirements and reduce environmental toll. In medicine, nanoscale drug delivery systems grant improved therapeutic precision by overcoming biological barriers and enhancing drug targeting to diseased tissues. Here, we loaded nanoscale drug-delivery systems with agricultural nutrients, and applied them to the leaves of tomato plants. We show that the nanoparticles - liposomes composed of plant-derived lipids, penetrate the leaf and translocate in a bidirectional manner, distributing to other leaves and to the roots...
May 17, 2018: Scientific Reports
https://www.readbyqxmd.com/read/29773504/discovery-of-novel-20s-proteasome-inhibitors-by-rational-topology-based-scaffold-hopping-of-bortezomib
#18
Yulong Xu, Xicheng Yang, Yiyi Chen, Hao Chen, Huijiao Sun, Wei Li, Qiong Xie, Linqian Yu, Liming Shao
A series of structurally novel proteasome inhibitors 1-12 have been developed based rational topology-based scaffold hopping of bortezomib. Among these novel proteasome inhibitors, compound 10 represents an important advance due to the comparable proteasome-inhibitory activity (IC50  = 9.7 nM) to bortezomib (IC50  = 8.3 nM), the remarkably higher BEI and SEI values and the effectiveness in metabolic stability. Therefore, compound 10 provides an excellent lead suitable for further optimization.
May 9, 2018: Bioorganic & Medicinal Chemistry Letters
https://www.readbyqxmd.com/read/29773268/recent-therapeutic-advances-in-juvenile-idiopathic-arthritis
#19
REVIEW
Gabriella Giancane, Alessandra Alongi, Silvia Rosina, Jessica Tibaldi, Alessandro Consolaro, Angelo Ravelli
Over the past two decades, the management of juvenile idiopathic arthritis (JIA) has been revolutionized by the increased tendency toward early aggressive interventions and the availability of the novel biologic medications. In 2017, three novel randomized controlled trials have evaluated the effectiveness and tolerability of golimumab and tocilizumab in polyarticular JIA, and shown that methotrexate may increase and prolong the effect of intra-articular corticosteroid injection in children with oligoarthritis...
August 2017: Best Practice & Research. Clinical Rheumatology
https://www.readbyqxmd.com/read/29773073/metabolome-analysis-based-design-and-engineering-of-a-metabolic-pathway-in-corynebacterium-glutamicum-to-match-rates-of-simultaneous-utilization-of-d-glucose-and-l-arabinose
#20
Hideo Kawaguchi, Kumiko Yoshihara, Kiyotaka Y Hara, Tomohisa Hasunuma, Chiaki Ogino, Akihiko Kondo
BACKGROUND: L-Arabinose is the second most abundant component of hemicellulose in lignocellulosic biomass, next to D-xylose. However, few microorganisms are capable of utilizing pentoses, and catabolic genes and operons enabling bacterial utilization of pentoses are typically subject to carbon catabolite repression by more-preferred carbon sources, such as D-glucose, leading to a preferential utilization of D-glucose over pentoses. In order to simultaneously utilize both D-glucose and L-arabinose at the same rate, a modified metabolic pathway was rationally designed based on metabolome analysis...
May 17, 2018: Microbial Cell Factories
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