keyword
MENU ▼
Read by QxMD icon Read
search

oligomer

keyword
https://www.readbyqxmd.com/read/28335581/biosynthesis-of-oligomeric-anthocyanins-from-grape-skin-extracts
#1
Jin-Woo Hwang, Sithranga Boopathy Natarajan, Yon-Suk Kim, Eun-Kyung Kim, Jae Woong Lee, Sang-Ho Moon, Byong-Tae Jeon, Pyo-Jam Park
We synthesized oligomeric anthocyanins from grape skin-derived monomeric anthocyanins such as anthocyanidin and proanthocyanidin by a fermentation technique using Aspergillus niger, crude enzymes and glucosidase. The biosyntheses of the oligomeric anthocyanins carried out by the conventional method using Aspergillus niger and crude enzymes were confirmed by ESI-MS. The molecular weight of the synthesized anthocyanin oligomers was determined using MALDI-MS. The yield of anthocyanin oligomers using crude enzymes was higher than that of the synthesis using Aspergillus fermentation...
March 21, 2017: Molecules: a Journal of Synthetic Chemistry and Natural Product Chemistry
https://www.readbyqxmd.com/read/28334501/unravelling-a-direct-role-for-polysaccharide-%C3%AE-strands-in-the-higher-order-structure-of-physical-hydrogels
#2
Anja Rüther, Aurelien Forget, Anjan Roy, Carolina Carballo, Florian Mießmer, Rina K Dukor, Laurence A Nafie, Christian Johannessen, V Prasad Shastri, Steffen Lüdeke
The mechanical properties of agarose-derived hydrogels depend on the scaffolding of the polysaccharide network. To identify and quantify such higher order structure, we applied Raman optical activity (ROA)-a spectroscopic technique that is highly sensitive toward carbohydrates-on native agarose and chemically modified agarose in the gel phase for the first time. By spectral global fitting, we isolated features that change as a function of backbone carboxylation (28, 40, 50, 60, 80, and 93 %) from other features that remain unchanged...
March 23, 2017: Angewandte Chemie
https://www.readbyqxmd.com/read/28332821/chiral-plasmonic-nanochains-via-the-self-assembly-of-gold-nanorods-and-helical-glutathione-oligomers-facilitated-by-cetyltrimethylammonium-bromide-micelles
#3
Jun Lu, Yi-Xin Chang, Ning-Ning Zhang, Ying Wei, Ai-Ju Li, Jia Tai, Yao Xue, Zhao-Yi Wang, Yang Yang, Li Zhao, Zhong-Yuan Lu, Kun Liu
Gold nanorods are excellent anisotropic building blocks for plasmonic chiral nanostructures. The near-infrared plasmonic band of nanorods makes them highly desirable for biomedical applications such as chiral bioimaging and sensing, in which a strong circular dichroism (CD) signal is required. Chiral assemblies of gold nanorods induced by self-associating peptides are especially attractive for this purpose as they exhibit plasmonic-enhanced chiroptical activity. Here, we showed that the presence of cetyltrimethylammonium bromide (CTAB) micelles in a gold nanorod solution promoted the self-association of l-/d-glutathione (GSH) and significantly enhanced the chirality of the resulting plasmonic nanochains...
March 23, 2017: ACS Nano
https://www.readbyqxmd.com/read/28332150/dynamic-nature-of-presenilin1-%C3%AE-secretase-implication-for-alzheimer-s-disease-pathogenesis
#4
REVIEW
Katarzyna Marta Zoltowska, Oksana Berezovska
Presenilin 1 (PS1) is a catalytic component of the γ-secretase complex, responsible for the intramembraneous cleavage of more than 90 type I transmembrane proteins, including Alzheimer's disease (AD)-related amyloid precursor protein (APP). The γ-secretase-mediated cleavage of the APP C-terminal membrane stub leads to the production of various amyloid β (Aβ) species. The assembly of Aβ into neurotoxic oligomers, which causes synaptic dysfunction and neurodegeneration, is influenced by the relative ratio of the longer (Aβ42/43) to shorter Aβ (Aβ40) peptides...
March 22, 2017: Molecular Neurobiology
https://www.readbyqxmd.com/read/28330937/raft-based-sphingomyelin-interactions-revealed-by-new-fluorescent-sphingomyelin-analogs
#5
Masanao Kinoshita, Kenichi G N Suzuki, Nobuaki Matsumori, Misa Takada, Hikaru Ano, Kenichi Morigaki, Mitsuhiro Abe, Asami Makino, Toshihide Kobayashi, Koichiro M Hirosawa, Takahiro K Fujiwara, Akihiro Kusumi, Michio Murata
Sphingomyelin (SM) has been proposed to form cholesterol-dependent raft domains and sphingolipid domains in the plasma membrane (PM). How SM contributes to the formation and function of these domains remains unknown, primarily because of the scarcity of suitable fluorescent SM analogs. We developed new fluorescent SM analogs by conjugating a hydrophilic fluorophore to the SM choline headgroup without eliminating its positive charge, via a hydrophilic nonaethylene glycol linker. The new analogs behaved similarly to the native SM in terms of their partitioning behaviors in artificial liquid order-disorder phase-separated membranes and detergent-resistant PM preparations...
March 22, 2017: Journal of Cell Biology
https://www.readbyqxmd.com/read/28330719/nicotinamide-mononucleotide-inhibits-jnk-activation-to-reverse-alzheimer-disease
#6
Zhiwen Yao, Wenhao Yang, Zhiqiang Gao, Peng Jia
Amyloid-β (Aβ) oligomers have been accepted as major neurotoxic agents in the therapy of Alzheimer's disease (AD). It has been shown that the activity of nicotinamide adenine dinucleotide (NAD+) is related with the decline of Aβ toxicity in AD. Nicotinamide mononucleotide (NMN), the important precursor of NAD+, is produced during the reaction of nicotinamide phosphoribosyl transferase (Nampt). This study aimed to figure out the potential therapeutic effects of NMN and its underlying mechanisms in APPswe/PS1dE9 (AD-Tg) mice...
March 18, 2017: Neuroscience Letters
https://www.readbyqxmd.com/read/28328018/abundance-correction-for-mass-discrimination-effects-in-polymer-mass-spectra
#7
Martin S Engler, Sarah Crotty, Markus J Barthel, Christian Pietsch, Ulrich S Schubert, Sebastian Böcker
RATIONALE: Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOFMS) is frequently used to analyze homo- and copolymers, i.e. for computing copolymer fingerprints. However, the oligomer abundances are influenced by mass discrimination, i.e. mass- and composition-dependent ionization. We have developed a computational method to correct the abundance bias caused by the mass discrimination. METHODS: MALDI-TOFMS in combination with computational methods was used to investigate three random copolymers with different ratios of styrene and isoprene...
May 30, 2016: Rapid Communications in Mass Spectrometry: RCM
https://www.readbyqxmd.com/read/28327181/soluble-oligomeric-amyloid-%C3%AE-induces-calcium-dyshomeostasis-that-precedes-synapse-loss-in-the-living-mouse-brain
#8
Michal Arbel-Ornath, Eloise Hudry, Josiah R Boivin, Tadafumi Hashimoto, Shuko Takeda, Kishore V Kuchibhotla, Steven Hou, Carli R Lattarulo, Arianna M Belcher, Naomi Shakerdge, Pariss B Trujillo, Alona Muzikansky, Rebecca A Betensky, Bradley T Hyman, Brian J Bacskai
BACKGROUND: Amyloid-β oligomers (oAβ) are thought to mediate neurotoxicity in Alzheimer's disease (AD), and previous studies in AD transgenic mice suggest that calcium dysregulation may contribute to these pathological effects. Even though AD mouse models remain a valuable resource to investigate amyloid neurotoxicity, the concomitant presence of soluble Aβ species, fibrillar Aβ, and fragments of amyloid precursor protein (APP) complicate the interpretation of the phenotypes. METHOD: To explore the specific contribution of soluble oligomeric Aβ (oAβ) to calcium dyshomeostasis and synaptic morphological changes, we acutely exposed the healthy mouse brain, at 3 to 6 months of age, to naturally occurring soluble oligomers and investigated their effect on calcium levels using in vivo multiphoton imaging...
March 21, 2017: Molecular Neurodegeneration
https://www.readbyqxmd.com/read/28326729/-study-of-human-leucine-rich-amelogenin-peptide-and-its-regulation-of-mineralization-by-cryogenic-transmission-electron-microscopy
#9
Tian Kun, Feng Xiaoyun, Du Qin, Liao Chuhang, Ren Xiaohua
OBJECTIVE: Recombinant human leucine-rich amelogenin peptide (LRAP) was studied by cryogenic transmission electron microscopy (TEM); evaluation focused on its self-assembly and crystal growth in vitro. METHODS: Human LRAP was recombined through prokaryotic expression vector pCold-SUMO and transformed into Escherichia coli BL21plys to acquire purified proteins. Cryogen TEM recorded assembly and self-assembling of LRAP from pH 3.5 to pH 8.0, and the hydroxyapatite crystal growth in the mixture of LRAP protein solution and artificial saliva was observed using TEM and selected area electron diffraction...
February 1, 2017: Hua Xi Kou Qiang Yi Xue za Zhi, Huaxi Kouqiang Yixue Zazhi, West China Journal of Stomatology
https://www.readbyqxmd.com/read/28325834/structural-model-of-dodecameric-heat-shock-protein-hsp21-flexible-n-terminal-arms-interact-with-client-proteins-while-c-terminal-tails-maintain-the-dodecamer-and-chaperone-activity
#10
Gudrun Rutsdottir, Johan Härmark, Yoran Weide, Hans Hebert, Morten Ib Rasmussen, Sven Wernersson, Michal Respondek, Mikael Akke, Peter Højrup, Philip J B Koeck, Christopher A G Söderberg, Cecilia Emanuelsson
Small heat shock proteins (sHsps) prevent aggregation of thermosensitive client proteins in a first line of defense against cellular stress. The mechanisms by which they perform this function have been hard to define due to limited structural information; currently there is only one high-resolution structure of a plant sHsp published, of the cytosolic Hsp16.9. We took interest in Hsp21, a chloroplast-localized sHsp crucial for plant stress resistance, which has even longer N-terminals arms than Hsp16.9, with a functionally important and conserved methionine-rich motif...
March 21, 2017: Journal of Biological Chemistry
https://www.readbyqxmd.com/read/28325311/improved-fluorescent-labeling-of-chitin-oligomers-chitinolytic-properties-of-acidic-mammalian-chitinase-under-somatic-tissue-ph-conditions
#11
Satoshi Wakita, Masahiro Kimura, Naoki Kato, Akinori Kashimura, Shunsuke Kobayashi, Naoto Kanayama, Misa Ohno, Shotaro Honda, Masayoshi Sakaguchi, Yasusato Sugahara, Peter O Bauer, Fumitaka Oyama
Acidic mammalian chitinase (AMCase) has been implicated in various pathophysiological conditions including asthma, allergic inflammation and food processing. AMCase is most active at pH 2.0, and its activity gradually decreases to up to pH 8. Here we analyzed chitin degradation by AMCase in weak acidic to neutral conditions by fluorophore-assisted carbohydrate electrophoresis established originally for oligosaccharides analysis. We found that specific fragments with slower-than-expected mobility as defined by chitin oligosaccharide markers were generated at pH 5...
May 15, 2017: Carbohydrate Polymers
https://www.readbyqxmd.com/read/28323849/bis-sulfosuccinimidyl-suberate-bs3-crosslinking-analysis-of-the-behavior-of-amyloid-%C3%AE-peptide-in-solution-and-in-phospholipid-membranes
#12
Jing-Ming Shi, Jie Pei, En-Qi Liu, Lin Zhang
The structure and state of amyloid-β peptide (Aβ) oligomers often need to be checked by reliable experimental methods. Electrophoresis is a commonly applied measurement method. However, due to the presence of detergents, oligomers are easily broken during electrophoresis, which makes it very hard to accurately assess Aβ aggregate states. In the current study, bis(sulfosuccinimidyl) suberate (BS3) was used to cross-link Aβ1-42 oligomers prior to electrophoresis. When compared to a previously reported Aβ cross-linking agent, glutaraldehyde, it was quite apparent that BS3 is more suitable for detecting intra-membrane Aβ oligomers and extra-membrane Aβ oligomers states...
2017: PloS One
https://www.readbyqxmd.com/read/28323518/synthesis-crystallization-and-preliminary-crystallographic-analysis-of-a-52-nucleotide-dna-2-ome-rna-oligomer-mimicking-10-23-dnazyme-in-the-complex-with-a-substrate
#13
Rafał Dolot, Milena Sobczak, Barbara Mikołajczyk, Barbara Nawrot
A 52-nucleotide DNA/2'-OMe-RNA oligomer mimicking 10-23 DNAzyme in the complex with its substrate was synthesized, purified and crystallized by the hanging-drop method using 0.8 M sodium potassium tartrate as a precipitant. A data set to 1.21 Å resolution was collected from a monocrystal at 100 K using synchrotron radiation on a beamline BL14.1 at BESSY. The crystal belonged to the P21 group with unit-cell a = 49.42, b = 24.69, c = 50.23, β = 118.48.
March 21, 2017: Nucleosides, Nucleotides & Nucleic Acids
https://www.readbyqxmd.com/read/28321603/similarities-and-differences-of-copper-and-zinc-cations-binding-to-biologically-relevant-peptides-studied-by-vibrational-spectroscopies
#14
Alicia Schirer, Youssef El Khoury, Peter Faller, Petra Hellwig
GHK and DAHK are biological peptides that bind both copper and zinc cations. Here we used infrared and Raman spectroscopies to study the coordination modes of both copper and zinc ions, at pH 6.8 and 8.9, correlating the data with the crystal structures that are only available for the copper-bound form. We found that Cu(II) binds to deprotonated backbone (amidate), the N-terminus and N(π) of the histidine side chain, in both GHK and DAHK, at pH 6.8 and 8.9. The data for the coordination of zinc at pH 6.8 points to two conformers including both nitrogens of a histidine residue...
March 20, 2017: Journal of Biological Inorganic Chemistry: JBIC
https://www.readbyqxmd.com/read/28321220/adjusted-particle-size-eliminates-the-need-of-linkage-of-antigen-and-adjuvants-for-appropriated-t-cell-responses-in-virus-like-particle-based-vaccines
#15
Ariane C Gomes, Anna Flace, Philippe Saudan, Franziska Zabel, Gustavo Cabral-Miranda, Aadil El Turabi, Vania Manolova, Martin F Bachmann
Since the discovery of the first virus-like particle (VLP) derived from hepatitis B virus in 1980 (1), the field has expanded substantially. Besides successful use of VLPs as safe autologous virus-targeting vaccines, the powerful immunogenicity of VLPs has been also harnessed to generate immune response against heterologous and even self-antigens (2-4). Linking adjuvants to VLPs displaying heterologous antigen ensures simultaneous delivery of all vaccine components to the same antigen-presenting cells. As a consequence, antigen-presenting cells, such as dendritic cells, will process and present the antigen displayed on VLPs while receiving costimulatory signals by the VLP-incorporated adjuvant...
2017: Frontiers in Immunology
https://www.readbyqxmd.com/read/28320942/egf-and-nrg-induce-phosphorylation-of-her3-erbb3-by-egfr-using-distinct-oligomeric-mechanisms
#16
Bettina van Lengerich, Christopher Agnew, Elias M Puchner, Bo Huang, Natalia Jura
Heteromeric interactions between the catalytically impaired human epidermal growth factor receptor (HER3/ERBB3) and its catalytically active homologs EGFR and HER2 are essential for their signaling. Different ligands can activate these receptor pairs but lead to divergent signaling outcomes through mechanisms that remain largely unknown. We used stochastic optical reconstruction microscopy (STORM) with pair-correlation analysis to show that EGF and neuregulin (NRG) can induce different extents of HER3 clustering that are dependent on the nature of the coexpressed HER receptor...
March 20, 2017: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/28319851/-31-p-dephased-13-c-detected-redor-for-nmr-crystallography-at-natural-isotopic-abundance
#17
Alexander I Greenwood, Mary C Clay, Chad M Rienstra
Typically, the process of NMR-based structure determination relies on accurately measuring a large number of internuclear distances to serve as restraints for simulated annealing calculations. In solids, the rotational-echo double-resonance (REDOR) experiment is a widely used approach to determine heteronuclear dipolar couplings corresponding to distances usually in the range of 1.5-8Å. A challenge in the interpretation of REDOR data is the degeneracy of symmetric subunits in an oligomer or equivalent molecules in a crystal lattice, which produce REDOR trajectories that depend explicitly on two or more distances instead of one...
February 28, 2017: Journal of Magnetic Resonance
https://www.readbyqxmd.com/read/28319795/theoretical-study-of-thieno-thiophene-based-low-band-gap-copolymers-and-substituent-effect-on-the-optoelectronic-properties-of-them
#18
Mehri Javan Khoshkholgh, Mohammad Reza Abolhassani, Farah Marsusi
This paper studies donor-acceptor systems which incorporate benzodithiophene (BDT), benzodifuran (BDF) and benzodipyrrole (BDP) units as the electron-rich monomer with TT unit representing the electron-deficient monomer. This research is based on employing density functional theory (DFT) and time-dependent DFT (TD-DFT). The highest occupied molecular orbitals (HOMO) and the lowest unoccupied molecular orbitals (LUMO), HOMO-LUMO gaps and dihedral-angles of these copolymers were calculated using oligomer extrapolation technique and periodic boundary condition (PBC) method...
March 7, 2017: Spectrochimica Acta. Part A, Molecular and Biomolecular Spectroscopy
https://www.readbyqxmd.com/read/28318364/defective-retrograde-transport-impairs-autophagic-clearance-in-alzheimer-disease-neurons
#19
Prasad Tammineni, Qian Cai
Macroautophagy/autophagy plays a key role in cellular quality control by eliminating protein aggregates and damaged organelles, which is essential for the maintenance of neuronal homeostasis. Defective autophagy has been implicated in the pathogenesis of Alzheimer disease (AD). In AD brains, autophagic vacuoles (AVs) accumulate massively within dystrophic neurites. This raises a fundamental question as to whether impaired autophagic clearance contributes to AD-associated autophagic stress. We recently revealed that AD neurons display defective retrograde transport and accumulation of amphisomes predominantly in axons and presynaptic terminals...
February 28, 2017: Autophagy
https://www.readbyqxmd.com/read/28318253/aminyl-radical-generation-via-tandem-norrish-type-i-photocleavage-%C3%AE-fragmentation-independent-generation-and-reactivity-of-the-2-deoxyadenosin-n6-yl-radical
#20
Liwei Zheng, Markus Griesser, Derek A Pratt, Marc M Greenberg
Formal hydrogen atom abstraction from the nitrogen-hydrogen bonds in purine nucleosides produces reactive intermediates that are important in nucleic acid oxidation. Herein we describe an approach for the independent generation of the purine radical resulting from hydrogen atom abstraction from the N6-amine of 2'-deoxyadenosine (dA•). The method involves sequential Norrish Type I photocleavage of a ketone (7b) and β-fragmentation of the initially formed alkyl radical (8b) to form dA• and acetone. The formation of dA• was followed by laser flash photolysis, which yields a transient with λmax ≈ 340 nm and a broader weaker absorption centered at ∼560 nm...
March 20, 2017: Journal of Organic Chemistry
keyword
keyword
105483
1
2
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read
×

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"