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https://www.readbyqxmd.com/read/28941406/theoretical-study-on-the-anomeric-effect-in-%C3%AE-substituted-tetrahydropyrans-and-piperidines
#1
Francisco A Martins, Josué M Silla, Matheus P Freitas
Conformational effects, including some controversial examples, have been reported in this work for 2-substituted tetrahydropyrans and piperidines, and for the respective protonated compounds [substituent = F, OH, OCH3, NH2, NHCH3 and N(CH3)2]. Hyperconjugation plays a major role in most cases, either due to endo or exo-anomeric interactions, especially when nitrogen is the electron donor to an antiperiplanar σ* orbital. This interaction also seems to contribute for the Perlin and reverse fluorine Perlin-like effects, which are related to the relative magnitude of (1)JC,H and (1)JC,F coupling constants, respectively, in axial and equatorial conformers...
September 15, 2017: Carbohydrate Research
https://www.readbyqxmd.com/read/28934733/exosomes-from-human-induced-pluripotent-stem-cell-derived-mesenchymal-stromal-cells-hipsc-mscs-protect-liver-against-hepatic-ischemia-reperfusion-injury-via-activating-sphingosine-kinase-and-sphingosine-1-phosphate-signaling-pathway
#2
Yingdong Du, Dawei Li, Conghui Han, Haoyu Wu, Longmei Xu, Ming Zhang, Jianjun Zhang, Xiaosong Chen
BACKGROUND/AIMS: This study aimed to evaluate the effects of exosomes produced by human-induced pluripotent stem cell-derived mesenchymal stromal cells (hiPSC-MSCs-Exo) on hepatic ischemia-reperfusion (I/R) injury, as well as the underlying mechanisms. METHODS: Exosomes derived from hiPSC-MSCs were isolated and characterized both biochemically and biophysically. hiPSC-MSCs-Exo were injected systemically into a murine ischemia/reperfusion injury model via the inferior vena cava, and then the therapeutic effects were evaluated...
September 21, 2017: Cellular Physiology and Biochemistry
https://www.readbyqxmd.com/read/28934497/systematic-analysis-of-dna-crosslink-repair-pathways-during-development-and-aging-in-caenorhabditis-elegans
#3
David M Wilson, Matthias Rieckher, Ashley B Williams, Björn Schumacher
DNA interstrand crosslinks (ICLs) are generated by endogenous sources and chemotherapeutics, and pose a threat to genome stability and cell survival. Using Caenorhabditis elegans mutants, we identify DNA repair factors that protect against the genotoxicity of ICLs generated by trioxsalen/ultraviolet A (TMP/UVA) during development and aging. Mutations in nucleotide excision repair (NER) components (e.g. XPA-1 and XPF-1) imparted extreme sensitivity to TMP/UVA relative to wild-type animals, manifested as developmental arrest, defects in adult tissue morphology and functionality, and shortened lifespan...
September 19, 2017: Nucleic Acids Research
https://www.readbyqxmd.com/read/28933544/conformational-dynamics-and-exchange-kinetics-of-n-formyl-and-n-acetyl-groups-substituting-3-amino-3-6-dideoxy-%C3%AE-d-galactopyranose-a-sugar-found-in-bacterial-o-antigen-polysaccharides
#4
Olof Engström, Hani Mobarak, Jonas Ståhle, Göran Widmalm
Three dimensional shape and conformation of carbohydrates are important factors in molecular recognition events and the N-acetyl group of a monosaccharide residue can function as a conformational gatekeeper whereby it influences the overall shape of the oligosaccharide. NMR spectroscopy and quantum mechanics (QM) calculations are used herein to investigate both the conformational preferences and the dynamic behavior of N-acetyl and N-formyl substituents of 3-amino-3,6-dideoxy-α-D-galactopyranose, a sugar and substitution patterns found in bacterial O-antigen polysaccharides...
September 21, 2017: Journal of Physical Chemistry. B
https://www.readbyqxmd.com/read/28933535/development-of-visible-light-induced-photoelectrochemical-platform-based-on-cyclometalated-iridium-iii-complex-for-bioanalysis
#5
Chunxiang Li, Weisen Lu, Ming Zhu, Bo Tang
The performance of the photoelectrochemical (PEC) bioanalysis relies closely on the properties of the usedphotoactive species. In this study, a visible-light induced PEC active species, [(C6)2Ir(dcbpy)]+PF6- (C6 = coumarin 6, dcbpy = 2,2'-bipyridine-4,4'-dicarboxylic acid) was prepared based on C6 with the stronger absorbance in the visible region. The as-prepared complex was characterized by 1H NMR,UV-visible absorption and cyclic voltammetry. It exhibits intense absorption in visible region at 480 nm with a molar extinction coefficient (ε) of more 40000 M-1cm-1, which is approximately twice that of Ru(bpy)32+...
September 21, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28933481/bowl-shaped-deformation-in-a-planar-aromatic-polycycle-upon-reduction-li-and-na-separated-dianions-of-the-aromatic-polycycle-5-6-11-12-di-o-phenylene-tetracene
#6
T Wombacher, R Goddard, C W Lehmann, J J Schneider
Herein we report the synthesis and crystal structures of three light alkali metal salts of the dianion of the polycyclic aromatic hydrocarbon 5,6:11,12-di-o-phenylenetetracene (LDOPT). The compounds are obtained by reaction of LDOPT with an excess of lithium or sodium metal in different O-donor solvents (DME, diglyme) and crystallize as naked, solvated-cation separated dianions exhibiting no interaction between the alkali metal ion and the aromatic π-system of LDOPT. Depending on the aprotic etheral solvent and the hardness of the alkaline metal agent a significant structural perturbation of the conjugated carbon framework of LDOPT is observed resulting in a bowl shaped curvature of the anionic π-perimeter, in contrast to its fully planar neutral state...
September 21, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
https://www.readbyqxmd.com/read/28933167/tunable-cyclization-strategy-for-the-synthesis-of-zizaene-allo-cedrane-seco-kaurane-and-seco-atesane-type-skeletons
#7
Qianqian Yang, Wenjing Ma, Gaopeng Wang, Wenli Bao, Xiaoshu Dong, Xuefeng Liang, Lizhi Zhu, Chi-Sing Lee
A versatile Lewis acid-mediated cyclization strategy has been developed for selectively establishing zizaene-, allo-cedrane-, seco-kaurane-, and seco-atesane-type skeletons. The zizaene- and seco-atesane-type skeletons can be obtained in a cascade manner, which involves Diels-Alder reaction of cyclic enones with bis-silyloxy dienes and carbocyclization of yne-enolates through Lewis acid dependent 5- or 6-exo-dig modes. This cyclization strategy was also employed for the core synthesis of tashironin.
September 21, 2017: Organic Letters
https://www.readbyqxmd.com/read/28931213/a-review-on-the-efficacy-and-toxicity-of-different-doxorubicin-nanoparticles-for-targeted-therapy-in-metastatic-breast-cancer
#8
REVIEW
Ayman Shafei, Wesam El-Bakly, Ahmed Sobhy, Omar Wagdy, Ahmed Reda, Omar Aboelenin, Amr Marzouk, Khalil El Habak, Randa Mostafa, Mahmoud A Ali, Mahmoud Ellithy
In metastatic breast cancer (MBC), the conventional doxorubicin (DOX) has various problems due to lack of selectivity with subsequent therapeutic failure and adverse effects. DOX- induced cardiotoxicity is a major problem that necessitates the presence of new forms to decrease the risk of associated morbidity. Nanoparticles (NPs) are considered an important approach to selectively increase drug accumulation inside tumor cells and thus decreasing the associated side effects. Tumor cells develop resistance to chemotherapeutic agents through multiple mechanisms, one of which is over expression of efflux transporters...
September 16, 2017: Biomedicine & Pharmacotherapy, Biomédecine & Pharmacothérapie
https://www.readbyqxmd.com/read/28926719/exosomes-derived-from-embryonic-stem-cells-inhibit-doxorubicin-and-inflammation-induced-pyroptosis-in-muscle-cells
#9
Zahra Tavakoli Dargani, Reetu Singla, Taylor Johnson, Rakesh C Kukreja, Dinender Kumar Singla
Doxorubicin (Dox) is an effective anticancer drug. Unfortunately, it causes cardio and muscle toxicity due to increased oxidative stress and inflammation; however, it remains unknown whether Dox induces "pyroptosis"- an inflammation mediated cell death. We investigated whether Dox induces pyroptosis in mouse soleus muscle (Sol 8) cells in vitro and to show the protective effect of embryonic stem cells-exosomes (ES-exos) on pyroptosis. Doxorubicin and inflammation induced in vitro model was generated. Pyroptosis was confirmed using immunohistochemistry and western blotting of putative markers caspase-1, IL1β and pro-inflammatory cytokine IL-18...
September 19, 2017: Canadian Journal of Physiology and Pharmacology
https://www.readbyqxmd.com/read/28923132/characterization-of-environmental-pseudomonas-aeruginosa-using-multilocus-sequence-typing-scheme
#10
Júlia Radó, Edit Kaszab, Tünde Petrovics, Judit Pászti, Balázs Kriszt, Sándor Szoboszlay
PURPOSE: The objectives of this study were to examine environmental (hydrocarbon degrading) Pseudomonas aeruginosa isolates with Multilocus Sequence Typing (MLST) and to determine their relevant features, such as serotype, virulence genes, biofilm forming ability and hydrocarbon degrading capacity. METHODOLOGY: The diversity of environmental isolates was assessed with an MLST scheme. Investigation of virulence determinants included serotyping, hemolytic activity test and the detection of virulence genes exoS, exoY, exoT, exoU, exoA...
September 19, 2017: Journal of Medical Microbiology
https://www.readbyqxmd.com/read/28919985/human-tumor-derived-exosomes-tex-regulate-treg-functions-via-cell-surface-signaling-rather-than-uptake-mechanisms
#11
Laurent Muller, Patricia Simms, Chang-Sook Hong, Michael I Nishimura, Edwin K Jackson, Simon C Watkins, Theresa L Whiteside
Tumor-derived exosomes (TEX) are ubiquitously present in the tumor microenvironment and plasma of cancer patients. TEX carry a cargo of multiple stimulatory and inhibitory molecules and deliver them to recipient cells, serving as a communication network for the tumor. The mechanisms TEX use for delivering messages to recipient cells were evaluated using PKH26-labeled TEX produced by cultured human tumor cells, exosomes produced by dendritic cells-derived exosomes (DEX), or exosomes isolated from plasma of cancer patients (EXO)...
2017: Oncoimmunology
https://www.readbyqxmd.com/read/28919421/exosomes-derived-from-human-umbilical-cord-blood-mesenchymal-stem-cells-stimulates-rejuvenation-of-human-skin
#12
Yoon-Jin Kim, Sae Mi Yoo, Hwan Hee Park, Hye Jin Lim, Yu-Lee Kim, Seunghee Lee, Kyung-Sun Kang, Kwang-Won Seo
Human umbilical cord blood-derived mesenchymal stem cells (UCB-MSCs) play an important role in cutaneous wound healing, and recent studies suggested that MSC-derived exosomes activate several signaling pathways, which are conducive in wound healing and cell growth. In this study, we investigated the roles of exosomes that are derived from USC-CM (USC-CM Exos) in cutaneous collagen synthesis and permeation. We found that USC-CM has various growth factors associated with skin rejuvenation. Our in vitro results showed that USC-CM Exos integrate in Human Dermal Fibroblasts (HDFs) and consequently promote cell migration and collagen synthesis of HDFs...
September 14, 2017: Biochemical and Biophysical Research Communications
https://www.readbyqxmd.com/read/28918582/removal-of-endrin-and-dieldrin-isomeric-pesticides-through-stereoselective-adsorption-behavior-on-the-graphene-oxide-magnetic-nanoparticles
#13
Kamlesh Shrivas, Archana Ghosale, Nidhi Nirmalkar, Arti Srivastava, Sunil Kumar Singh, Sandip S Shinde
A novel stereoselective removal behavior of isomeric endrin and dieldrin pesticides from sample solution is demonstrated using nanocomposite of graphene oxide (GO) and iron oxide (Fe3O4) magnetic nanoparticles (MNPs). The removal efficiency of endrin and dieldrin was found higher when GO-MNPs was used as a separating probe than the individual use of GO and MNPs. The removal efficiency of both the pesticides was found to be more favorable when the dosage amount of GO-MNPs was 30 mg for 30-min contact time with pH 4...
September 16, 2017: Environmental Science and Pollution Research International
https://www.readbyqxmd.com/read/28916320/exosomes-carring-gag-env-of-alv-j-possess-negative-effect-on-immunocytes
#14
Guihua Wang, Zhenzhen Wang, Pingping Zhuang, Xiaomin Zhao, Ziqiang Cheng
J subgroup avian leukosis virus (ALV-J) is an exogenous retrovirus of avian. A key feature of ALV-J infection is leading to severe immunosuppressive characteristic of diseases. Viral components of retrovirus were reported closely associated with immunosuppression, and several similarities between exosomes and retrovirus preparations have lead to the hypotheses of retrovirus hijacker exosomes pathway. In this study, we purified exosomes from DF-1 cells infected and uninfected by ALV-J. Electron microscopy and mass spectrometry (MS) analysis showed that ALV-J not only increased the production of exosomes from ALV-J infected DF-1 cells (Exo-J) but also stimulated some proteins expression, especially ALV-J components secreted in exosomes...
September 12, 2017: Microbial Pathogenesis
https://www.readbyqxmd.com/read/28914450/changes-in-composition-and-content-of-food-derived-peptide-in-human-blood-after-daily-ingestion-of-collagen-hydrolysate-for-4-weeks
#15
Yasutaka Shigemura, Asahi Suzuki, Mihoko Kurokawa, Yosio Sato, Kenji Sato
BACKGROUND: daily ingestion of collagen hydrolysate improves skin and joint conditions. It has been speculated that the beneficial effects are exerted by food-derived hydroxyproline (Hyp) peptides, which are detected in human blood after single ingestions. In the present study, to investigate the detailed relationship of the beneficial effects of Hyp-peptides, we examined the concentrations of Hyp-peptides in human blood before and after daily ingestion. RESULTS: Hyp-peptides increased to a maximum level at 1 h after ingestion and reverted to their initial levels within 24 h during daily ingestion...
September 15, 2017: Journal of the Science of Food and Agriculture
https://www.readbyqxmd.com/read/28911122/data-exploration-quality-control-and-statistical-analysis-of-chip-exo-nexus-experiments
#16
Rene Welch, Dongjun Chung, Jeffrey Grass, Robert Landick, Sündüz Keles
ChIP-exo/nexus experiments rely on innovative modifications of the commonly used ChIP-seq protocol for high resolution mapping of transcription factor binding sites. Although many aspects of the ChIP-exo data analysis are similar to those of ChIP-seq, these high throughput experiments pose a number of unique quality control and analysis challenges. We develop a novel statistical quality control pipeline and accompanying R/Bioconductor package, ChIPexoQual, to enable exploration and analysis of ChIP-exo and related experiments...
September 6, 2017: Nucleic Acids Research
https://www.readbyqxmd.com/read/28904411/structural-and-functional-properties-biosynthesis-and-patenting-trends-of-bacterial-succinoglycan-a-review
#17
REVIEW
Urmi Halder, Aparna Banerjee, Rajib Bandopadhyay
The exopolysaccharide succinoglycan is produced mainly by a large number of soil microbes of Agrobacterium, Rhizobium or Pseudomonas genera etc. Structural properties of succinoglycan are unique in terms of its thermal stability and superior viscosifying property. Unlike the other highly commercialized bacterial exopolysaccharides like dextran or xanthan, mass scale application of succinoglycan has not been that much broadly explored yet. Bacterial succinoglycan is found suitable as a viscosifying and emulsifying agent in food industry, in gravel packing or fluid-loss control agent etc...
September 2017: Indian Journal of Microbiology
https://www.readbyqxmd.com/read/28902995/anion-%C3%AF-catalysis-on-fullerenes
#18
Javier López-Andarias, Antonio Frontera, Stefan Matile
Anion-π interactions on fullerenes are about as poorly explored as the use of fullerenes in catalysis. However, strong exchange-correlation contributions and the localized π holes on their surface promise unique selectivities. To elaborate on this promise, tertiary amines are attached nearby. Dependent on their positioning, the resulting stabilization of anionic transition states on fullerenes is shown to accelerate disfavored enolate addition and exo Diels-Alder reactions enantioselectively. The found selectivities are consistent with computational simulations, particularly concerning the discrimination of differently planarized and charge-delocalized enolate tautomers by anion-π interactions...
September 13, 2017: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/28901773/transformation-of-the-b-ring-to-the-c-ring-of-bryostatins-by-csp-3-h-amination-and-z-to-e-isomerization
#19
Ji Lu, Yuebao Zhang, WenYu Yang, Qianyou Guo, Lu Gao, Zhenlei Song
An interesting approach to transform the B ring of bryostatins to the C ring has been developed. The key tactics of the approach feature an intramolecular Csp(3)-H bond amination to form spirocyclic hemiaminal, which undergoes ring opening to afford the C ring found in bryostatin 17. The subsequent epoxidation/oxidation sequence results in Z to E isomerization of the exo-cyclic enoate, delivering the common precursor, which could be transformed into the C ring found in bryostatins 1, 2, 4-9, 12, 14, and 15.
September 13, 2017: Organic Letters
https://www.readbyqxmd.com/read/28894941/evolutionary-coincidence-of-adaptive-changes-in-exuperantia-and-the-emergence-of-bicoid-in-cyclorrhapha-diptera
#20
Janaina Lima de Oliveira, Iderval Silva Sobrinho-Junior, Samira Chahad-Ehlers, Reinaldo Alves de Brito
The great radiation in the infraorder Cyclorrhapha involved several morphological and molecular changes, including important changes in anterior egg development. During Drosophila oogenesis, exuperantia (exu) is critical for localizing bicoid (bcd) messenger RNA (mRNA) to the anterior region of the oocyte. Because it is phylogenetically older than bcd, which is exclusive to Cyclorrhapha, we hypothesize that exu has undergone adaptive changes to enable this new function. Although exu has been well studied in Drosophila, there is no functional or transcriptional information about it in any other Diptera...
September 11, 2017: Development Genes and Evolution
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