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https://www.readbyqxmd.com/read/28432922/restricted-access-magnetic-core-mesoporous-shell-microspheres-with-c8-modified-interior-pore-walls-for-the-identification-of-20-s-protopanaxadiol-metabolites-in-rat-plasma-using-uplc-q-tof-ms-ms
#1
Jin Ling, Yingjia Yu, Jianan Feng, Changjiang Xu, Jiebing Jiang, Liping Wang, Jiakun Long, Yan Li, Gengli Duan
In the present study, a novel sample preparation method based on magnetic core-mesoporous shell microspheres with C8-modified interior pore walls (C8-Fe3O4@mSiO2) was established for the identification of 20(S)-protopanaxadiol (PPD) metabolites in rat plasma by UPLC-Q-TOF-MS/MS analysis. C8-Fe3O4@mSiO2 allowed selective extraction of PPD metabolites from rat plasma by excluding macromolecules in the plasma owing to size exclusion effect. Five extraction conditions including the amount of C8-Fe3O4@mSiO2 microspheres used, extraction time, elution solvents, elution volume, and elution time were investigated and optimized...
April 3, 2017: Journal of Chromatography. B, Analytical Technologies in the Biomedical and Life Sciences
https://www.readbyqxmd.com/read/28431964/microvillus-specific-protein-tyrosine-phosphatase-sap-1-plays-a-role-in-regulating-the-intestinal-paracellular-transport-of-macromolecules
#2
Shingo Mori, Noriyasu Kamei, Yoji Murata, Kozo Takayama, Takashi Matozaki, Mariko Takeda-Morishita
The stomach cancer associated protein tyrosine phosphatase 1 (SAP-1) is a receptor-type protein tyrosine phosphatase that is specifically expressed on the apical membrane of the intestinal epithelium. SAP-1 is known to maintain the balance of phosphorylation of proteins together with protein kinases, however, its biological function and impact on pharmacokinetics in the intestine remain unclear. The present study, therefore, aimed to clarify the relationship between SAP-1 and the intestinal absorption behaviors of typical transporter substrates and macromolecules...
April 18, 2017: Journal of Pharmaceutical Sciences
https://www.readbyqxmd.com/read/28431877/synthesis-and-evaluation-of-pyridinium-polyoxometalates-as-anti-hiv-1-agents
#3
Shunyi Wang, Wuji Sun, Qin Hu, Hong Yan, Yi Zeng
The unique properties of polyoxometalates, such as molecular polarity, redox potential, surface charge distribution, shape and acidity, influence their response of recognition to targeted biological macromolecules. By using PM-19 (K7PTi2W10O40) as a lead-compound, a series of novel pyridinium polyoxometalates (A7PTi2W10O40), which hadn't been reported in literatures, were designed and synthesized. The evaluation was conducted using the single-cycle pseudovirus infection assay (TZM-bl assay), CCK-8 method was used for determining the cytotoxicity...
April 8, 2017: Bioorganic & Medicinal Chemistry Letters
https://www.readbyqxmd.com/read/28430426/the-rosetta-all-atom-energy-function-for-macromolecular-modeling-and-design
#4
Rebecca Faye Alford, Andrew Leaver-Fay, Jeliazko R Jeliazkov, Matthew J O'Meara, Frank P DiMaio, Hahnbeom Park, Maxim V Shapovalov, P Douglas Renfrew, Vikram Khipple Mulligan, Kalli Kappel, Jason W Labonte, Michael Steven Pacella, Richard Bonneau, Philip Bradley, Roland L Dunbrack, Rhiju Das, David Baker, Brian Kuhlman, Tanja Kortemme, Jeffrey J Gray
Over the past decade, the Rosetta biomolecular modeling suite has informed diverse biological questions and engineering challenges ranging from interpretation of low-resolution structural data to design of nanomaterials, protein therapeutics, and vaccines. Central to Rosetta's success is the energy function: a model parameterized from small molecule and X-ray crystal structure data used to approximate the energy associated with each biomolecule conformation. This paper describes the mathematical models and physical concepts that underlie the latest Rosetta Energy Function, REF15...
April 21, 2017: Journal of Chemical Theory and Computation
https://www.readbyqxmd.com/read/28430138/nanomaterials-as-assisted-matrix-of-laser-desorption-ionization-time-of-flight-mass-spectrometry-for-the-analysis-of-small-molecules
#5
REVIEW
Minghua Lu, Xueqing Yang, Yixin Yang, Peige Qin, Xiuru Wu, Zongwei Cai
Matrix-assisted laser desorption/ionization (MALDI), a soft ionization method, coupling with time-of-flight mass spectrometry (TOF MS) has become an indispensible tool for analyzing macromolecules, such as peptides, proteins, nucleic acids and polymers. However, the application of MALDI for the analysis of small molecules (<700 Da) has become the great challenge because of the interference from the conventional matrix in low mass region. To overcome this drawback, more attention has been paid to explore interference-free methods in the past decade...
April 21, 2017: Nanomaterials
https://www.readbyqxmd.com/read/28429501/formation-of-macromolecules-in-wheat-gluten-starch-mixtures-during-twin-screw-extrusion-effect-of-different-additives
#6
Kaiqiang Wang, Cheng Li, Bingzhi Wang, Wen Yang, Shuizhong Luo, Yanyan Zhao, Shaotong Jiang, Dongdong Mu, Zhi Zheng
BACKGROUND: Wheat gluten comprises a good quality and inexpensive vegetable protein with an ideal amino acid composition. To expand the potential application of wheat gluten in the food industry, the effect of different additives on the physicochemical and structural properties of wheat gluten/starch mixtures during twin-screw extrusion was investigated. RESULTS: Macromolecules were observed to form in wheat gluten/starch mixtures during twin-screw extrusion, which may be ascribed to the formation of new disulfide bonds and non-covalent interactions, as well as Maillard reaction products...
April 21, 2017: Journal of the Science of Food and Agriculture
https://www.readbyqxmd.com/read/28429287/protective-effect-of-selenoprotein-x-against-oxidative-stress-induced-cell-apoptosis-in-human-hepatocyte-lo2-cells-via-the-p38-pathway
#7
Jia-Yong Tang, Ai-Hua He, Gang Jia, Guang-Mang Liu, Xiao-Ling Chen, Jing-Yi Cai, Hai-Ying Shang, Jin-Qiu Liao, Hua Zhao
Oxidative stress, as mediated by ROS (reactive oxygen species), is a significant factor in initiating the cells damaged by affecting cellular macromolecules and impairing their biological functions; SelX, a selenoprotein also known as MsrB1 belonging to the methionine sulfoxide reductase (Msr) family, is the redox repairing enzyme and involved in redox-related functions. In order to more precisely analyze the relationship between oxidative stress, cell oxidative damage, and SelX, we stably overexpressed porcine Selx full-length cDNA in human normal hepatocyte (LO2) cells...
April 20, 2017: Biological Trace Element Research
https://www.readbyqxmd.com/read/28429156/crystallization-and-preliminary-x-ray-diffraction-analysis-of-a-mammal-inositol-1-3-4-5-6-pentakisphosphate-2-kinase
#8
Elsa Franco-Echevarría, Julia Sanz-Aparicio, Nathalie Troffer-Charlier, Arnaud Poterszman, Beatriz González
Inositol 1,3,4,5,6-pentakisphosphate 2-kinase (IP5 2-K) is an enzyme that catalyses the formation of phytic acid (IP6) from IP5 and ATP. In mammals, IP6 is involved in multiple events such as DNA repair and mRNA edit and it is the precursor of inositol pyrophosphates, emerging compounds shown to have an essential role in apoptosis. In addition, IP5 2-K have functions in cells independently of its catalytic activity, for example in rRNA biogenesis. We pursue the structure determination of a mammal IP5 2-K by Protein Crystallography...
April 21, 2017: Protein Journal
https://www.readbyqxmd.com/read/28428974/perspective-a-toolbox-for-protein-structure-determination-in-physiological-environment-through-oriented-2d-ordered-site-specific-immobilization
#9
M Altissimo, M Kiskinova, R Mincigrucci, L Vaccari, C Guarnaccia, C Masciovecchio
Revealing the structure of complex biological macromolecules, such as proteins, is an essential step for understanding the chemical mechanisms that determine the diversity of their functions. Synchrotron based X-ray crystallography and cryo-electron microscopy have made major contributions in determining thousands of protein structures even from micro-sized crystals. They suffer from some limitations that have not been overcome, such as radiation damage, the natural inability to crystallize a number of proteins, and experimental conditions for structure determination that are incompatible with the physiological environment...
July 2017: Structural Dynamics (Melville, N.Y.)
https://www.readbyqxmd.com/read/28426174/solid-phase-synthesis-of-a-seventh-generation-inverse-poly-amidoamine-dendrimer-importance-of-the-loading-ratio-on-the-resin
#10
Chai-Lin Kao, Adela Ya-Ting Huang, Hui-Ting Chen
Here, this study overcomes the current barriers to efficient solid-phase synthesis of high-generation dendrimers by decreasing the loading ratio on the resin. G7 inverse poly(amidoamine) dendrimer is now prepared, for the first time, through a solid-phase synthesis using only 50% of the available reactive sites and by choosing a large resin. This preparation takes only 15 d to afford highly pure product in 80% yield with precipitation being the only purification procedure used. The results clearly show the amount of the initial monomer loaded on the resin to be a vital factor for the ability to use solid-phase synthesis to produce large dendrimers...
April 20, 2017: Macromolecular Rapid Communications
https://www.readbyqxmd.com/read/28426159/open-microfluidic-gel-electrophoresis-rapid-and-low-cost-separation-and-analysis-of-dna-at-the-nanoliter-scale
#11
Ludwig Gutzweiler, Tobias Gleichmann, Laurent Tanguy, Peter Koltay, Roland Zengerle, Lutz Riegger
Gel electrophoresis is one of the most applied and standardized tools for separation and analysis of macromolecules and their fragments in academic research and in industry. In this work we present a novel approach for conducting on-demand electrophoretic separations of DNA molecules in open microfluidic (OM) systems on planar polymer substrates. The approach combines advantages of slab gel, capillary- & chip-based methods offering low consumable costs (<0.1 $) circumventing cost intensive microfluidic chip fabrication, short process times (5 minutes per analysis) and high sensitivity (4 ng/μl dsDNA) combined with reasonable resolution (17 bases)...
April 20, 2017: Electrophoresis
https://www.readbyqxmd.com/read/28425584/changes-in-ciap2-survivin-and-bimel-expression-characterize-the-switch-from-autophagy-to-apoptosis-in-prolonged-starvation
#12
A Hay-Koren, S Bialik, V Levin-Salomon, A Kimchi
BACKGROUND: Autophagy is a catabolic process involving the engulfment of cytoplasmic content within autophagosomes followed by their delivery to lysosomes. This process is a survival mechanism, enabling cells to cope with nutrient deprivation by degradation and recycling of macromolecules. Yet during continued stress such as prolonged starvation, a switch from autophagy to apoptosis is often detected. OBJECTIVE: In this work, we characterized the temporal dynamics of the transition from autophagy towards apoptosis with the aim of elucidating the molecular mechanism regulating the switch from survival autophagy to apoptotic cell death...
May 2017: Journal of Internal Medicine
https://www.readbyqxmd.com/read/28425498/a-new-phenomenon-sub-tg-solid-state-plasticity-induced-bonding-in-polymers
#13
Nikhil Padhye, David M Parks, Bernhardt L Trout, Alexander H Slocum
Polymer self-adhesion due to the interdiffusion of macromolecules has been an active area of research for several decades. Here, we report a new phenomenon of sub-Tg, solid-state, plasticity-induced bonding; where amorphous polymeric films were bonded together in a period of time on the order of a second in the solid-state at ambient temperatures, up to 60 K below their glass transition temperature (Tg), by subjecting them to active plastic deformation. Despite the glassy regime, the bulk plastic deformation triggered the requisite molecular mobility of the polymer chains, causing interpenetration across the interfaces held in contact...
April 20, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28424711/genomic-molecular-evolution-and-expression-analysis-of-genes-encoding-putative-classical-agps-lysine-rich-agps-and-ag-peptides-in-brassica-rapa
#14
Tianyu Han, Heng Dong, Jie Cui, Ming Li, Sue Lin, Jiashu Cao, Li Huang
Arabinogalactan proteins (AGPs) belong to a class of Pro/Hyp-rich glycoproteins and are some of the most complex types of macromolecules found in plants. In the economically important plant species, Brassica rapa, only chimeric AGPs have been identified to date. This has significantly limited our understanding of the functional roles of AGPs in this plant. In this study, 64 AGPs were identified in the genome of B. rapa, including 33 classical AGPs, 28 AG peptides and three lys-rich AGPs. Syntenic gene analysis between B...
2017: Frontiers in Plant Science
https://www.readbyqxmd.com/read/28424408/synthetic-lethality-of-glutaminolysis-inhibition-autophagy-inactivation-and-asparagine-depletion-in-colon-cancer
#15
Jiaqiu Li, Ping Song, Liyuan Zhu, Neelum Aziz, Qiyin Zhou, Yulong Zhang, Wenxia Xu, Lifeng Feng, Dingwei Chen, Xian Wang, Hongchuan Jin
Cancer cells reprogram metabolism to coordinate their rapid growth. They addict on glutamine metabolism for adenosine triphosphate generation and macromolecule biosynthesis. In this study, we report that glutamine deprivation retarded cell growth and induced prosurvival autophagy. Autophagy inhibition by chloroquine significantly enhanced glutamine starvation induced growth inhibition and apoptosis activation. Asparagine deprivation by L-asparaginase exacerbated growth inhibition induced by glutamine starvation and autophagy blockage...
April 5, 2017: Oncotarget
https://www.readbyqxmd.com/read/28423901/estimation-of-nanodiamond-surface-charge-density-from-zeta-potential-and-molecular-dynamics-simulations
#16
Zhenpeng Ge, Yi Wang
Molecular dynamics simulations of nanoparticles (NPs) are increasingly used to study their interactions with various biological macromolecules. Such simulations generally require detailed knowledge of the surface composition of the NP under investigation. Even for some well-characterized nanoparticles, however, this knowledge is not always available. An example is nanodiamond, a nanoscale diamond particle with surface dominated by oxygen-containing functional groups. In this work, we explore using the harmonic restraint method developed by Venable et al...
April 20, 2017: Journal of Physical Chemistry. B
https://www.readbyqxmd.com/read/28422082/molecular-imprinting-of-macromolecules-for-sensor-applications
#17
REVIEW
Yeşeren Saylan, Fatma Yilmaz, Erdoğan Özgür, Ali Derazshamshir, Handan Yavuz, Adil Denizli
Molecular recognition has an important role in numerous living systems. One of the most important molecular recognition methods is molecular imprinting, which allows host compounds to recognize and detect several molecules rapidly, sensitively and selectively. Compared to natural systems, molecular imprinting methods have some important features such as low cost, robustness, high recognition ability and long term durability which allows molecularly imprinted polymers to be used in various biotechnological applications, such as chromatography, drug delivery, nanotechnology, and sensor technology...
April 19, 2017: Sensors
https://www.readbyqxmd.com/read/28421460/flow-arrest-intra-arterial-delivery-of-small-tat-decorated-and-neutral-micelles-to-gliomas
#18
Juliane Nguyen, Shaolie S Hossain, Johann R N Cooke, Jason A Ellis, Michael B Deci, Charles W Emala, Jeffrey N Bruce, Irving J Bigio, Robert M Straubinger, Shailendra Joshi
The cell-penetrating trans-activator of transcription (TAT) is a cationic peptide derived from human immunodeficiency virus-1. It has been used to facilitate macromolecule delivery to various cell types. This cationic peptide is capable of crossing the blood-brain barrier and therefore might be useful for enhancing the delivery of drugs that target brain tumors. Here we test the efficiency with which relatively small (20 nm) micelles can be delivered by an intra-arterial route specifically to gliomas. Utilizing the well-established method of flow-arrest intra-arterial injection we compared the degree of brain tumor deposition of cationic TAT-decorated micelles versus neutral micelles...
April 18, 2017: Journal of Neuro-oncology
https://www.readbyqxmd.com/read/28418240/enzymatic-carbon-sulfur-bond-formation-in-natural-product-biosynthesis
#19
Kyle L Dunbar, Daniel H Scharf, Agnieszka Litomska, Christian Hertweck
Sulfur plays a critical role for the development and maintenance of life on earth, which is reflected by the wealth of primary metabolites, macromolecules, and cofactors bearing this element. Whereas a large body of knowledge has existed for sulfur trafficking in primary metabolism, the secondary metabolism involving sulfur has long been neglected. Yet, diverse sulfur functionalities have a major impact on the biological activities of natural products. Recent research at the genetic, biochemical, and chemical levels has unearthed a broad range of enzymes, sulfur shuttles, and chemical mechanisms for generating carbon-sulfur bonds...
April 18, 2017: Chemical Reviews
https://www.readbyqxmd.com/read/28417635/crystallization-of-amphiphilic-dna-c-stars
#20
Ryan A Brady, Nicholas J Brooks, Pietro Cicuta, Lorenzo Di Michele
Many emerging technologies require materials with well-defined three-dimensional nanoscale architectures. Production of these structures is currently underpinned by self-assembling amphiphilic macromolecules or engineered all-DNA building blocks. Both of these approaches produce restricted ranges of crystal geometries due to synthetic amphiphiles' simple shape and limited specificity, or the technical difficulties in designing space-filling DNA motifs with targeted shapes. We have overcome these limitations with amphiphilic DNA nanostructures, or "C-Stars", that combine the design freedom and facile functionalization of DNA-based materials with robust hydrophobic interactions...
April 20, 2017: Nano Letters
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