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https://www.readbyqxmd.com/read/29144759/degree-of-unsaturation-and-backbone-orientation-of-amphiphilic-macromolecules-influence-local-lipid-properties-in-large-unilamellar-vesicles
#1
Kathryn E Uhrich, Alysha Moretti, Bin Zhang, Bernice Lee, Meenakshi Dutt
Liposomes have become increasingly common in the delivery of bioactive agents due to their ability to encapsulate hydrophobic and hydrophilic drugs with excellent biocompatibility. While commercial liposome formulations improve bioavailability of otherwise quickly eliminated or insoluble drugs, tailoring formulation properties for specific uses has become a focus of liposome research. Here, we report the design, synthesis, and characterization of two series of amphiphilic macromolecules (AMs), consisting of acylated polyol backbones conjugated to poly(ethylene glycol) (PEG) that can serve as the sole additives to stabilize and control hydrophilic molecule release rates from distearoyl-phosphatidylcholine- (DSPC-) based liposomes...
November 16, 2017: Langmuir: the ACS Journal of Surfaces and Colloids
https://www.readbyqxmd.com/read/29144302/fouling-mitigation-in-anaerobic-membrane-bioreactors-using-fluidized-resin-beads
#2
B Düppenbecker, J Behnisch, M Engelhart, P Cornel
This study focuses on the use of fluidized resin beads to mitigate fouling during ultrafiltration (UF) of the effluent of an anaerobic bioreactor. Two different module configurations were tested: A fluidized bed of resin beads was generated in a tubular UF membrane, and a hollow fiber (HF) UF membrane was submerged into a fluidized bed, respectively. During filtration of anaerobically treated synthetic wastewater using the tubular module, fluidized resin beads with a diameter of 0.5-0.71 mm did not show any beneficial effect...
November 2017: Water Science and Technology: a Journal of the International Association on Water Pollution Research
https://www.readbyqxmd.com/read/29144019/pegylated-precision-segments-based-on-sequence-defined-thiolactone-oligomers
#3
Sensu Celasun, Filip E Du Prez, Hans G Börner
A straightforward access route to multifunctional block copolymers, combining a poly(ethylene glycol) (PEG) block and a monodisperse segment with discrete monomer sequence based on thiolactone chemistry, is described. Exploiting an inverse conjugation strategy on a PEG preloaded poly(styrene) synthesis resin enables the convenient introduction of a predefined PEG-block at the α-terminus of thiolactone-based sequence-defined oligomers. Reaction conditions for the stepwise, submonomer synthesis at polar solid supports are optimized, using sequential synthesis on a model resin that enables to isolate and determine the purity of the oligomer segments by liquid chromatography-electrospray ionization mass spectrometry analysis...
November 16, 2017: Macromolecular Rapid Communications
https://www.readbyqxmd.com/read/29143948/label-free-nmr-based-dissociation-kinetics-determination
#4
Pablo Trigo-Mouriño, Christian Griesinger, Donghan Lee
Understanding the dissociation of molecules is the basis to modulate interactions of biomedical interest. Optimizing drugs for dissociation rates is found to be important for their efficacy, selectivity, and safety. Here, we show an application of the high-power relaxation dispersion (RD) method to the determination of the dissociation rates of weak binding ligands from receptors. The experiment probes proton RD on the ligand and, therefore, avoids the need for any isotopic labeling. The large ligand excess eases the detection significantly...
November 16, 2017: Journal of Biomolecular NMR
https://www.readbyqxmd.com/read/29143522/mmp-2-sensitive-ha-end-conjugated-poly-amidoamine-dendrimers-via-click-reaction-to-enhance-drug-penetration-into-solid-tumor
#5
Min Han, Ming-Yi Huang-Fu, Wang-Wei Guo, Ningning Guo, Jiejian Chen, Huina Liu, Zhiqi Xie, Mengting Lin, Qichun Wei, Jianqing Gao
Currently, the limited tumor penetration of nanoparticles remains a major challenge of cancer nanomedicine. Herein, we propose a size-shrinkable, drug delivery system based on a polysaccharide-modified dendrimer with tumor microenvironment responsiveness for the first time to our knowledge, which was formed by conjugating the terminal glucose of hyaluronic acid (HA) to the superficial amidogen of poly(amidoamine) (PAMAM), using a matrix metalloproteinase-2 (MMP-2)-cleavable peptide (PLGLAG) via click reaction...
November 16, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/29142018/terahertz-dictating-the-frequency-of-life-do-macromolecular-vibrational-modes-impose-thermal-limitations-on-terrestrial-life
#6
Kieran Hand, Edwin Yates
Conditions on exoplanets include elevated temperatures and pressures. The response of carbon-based biological macromolecules to such conditions is then relevant to the viability of life. The capacity of proteins and ribozymes to catalyse reactions or bind receptors, and nucleic acids to convey information, depends on them sampling different conformational states. These are determined by macromolecular vibrational states, or phonon modes, accessible using terahertz (THz: 10(12)Hz) absorption spectroscopy. THz spectra of biological macromolecules exhibit broad absorption at approximately 6 THz (equating to approx...
November 2017: Journal of the Royal Society, Interface
https://www.readbyqxmd.com/read/29141585/transcriptome-analysis-in-petals-and-leaves-of-chrysanthemums-with-different-chlorophyll-levels
#7
Akemi Ohmiya, Katsutomo Sasaki, Kenji Nashima, Chihiro Oda-Yamamizo, Masumi Hirashima, Katsuhiko Sumitomo
BACKGROUND: Chlorophylls (Chls) are magnesium-containing tetrapyrrole macromolecules responsible for the green color in plants. The Chl metabolic pathway has been intensively studied and nearly all the enzymes involved in the pathway have been identified and characterized. Synthesis and activity of these enzymes are tightly regulated in tissue- and developmental stage-specific manners. Leaves contain substantial amounts of Chls because Chls are indispensable for photosynthesis. In contrast, petals generally contain only trace amounts of Chls, which if present would mask the bright petal color...
November 15, 2017: BMC Plant Biology
https://www.readbyqxmd.com/read/29141425/macromolecules-with-amphiphilic-monomer-units-at-interface-of-two-immiscible-liquids
#8
A A Glagoleva, V V Vasilevskaya
The adsorption of macromolecules with amphiphilic monomer units at the liquid-liquid interface was studied. The amphiphilic structure of monomer units with groups selectively interacting with α and β liquids was described by the A-graft-B dumbbell model. The calculations were performed for the symmetrical interaction of A and B groups with liquids, different selectivity parameters ξ and degree of polymerization N. The simulations indicate a three-step adsorption scenario, including non-adsorbed, weak and strong localization states...
November 14, 2017: Journal of Chemical Physics
https://www.readbyqxmd.com/read/29141043/lateral-migration-of-electrospun-hydrogel-nanofilaments-in-an-oscillatory-flow
#9
Sylwia Pawłowska, Paweł Nakielski, Filippo Pierini, Izabela K Piechocka, Krzysztof Zembrzycki, Tomasz A Kowalewski
The recent progress in bioengineering has created great interest in the dynamics and manipulation of long, deformable macromolecules interacting with fluid flow. We report experimental data on the cross-flow migration, bending, and buckling of extremely deformable hydrogel nanofilaments conveyed by an oscillatory flow into a microchannel. The changes in migration velocity and filament orientation are related to the flow velocity and the filament's initial position, deformation, and length. The observed migration dynamics of hydrogel filaments qualitatively confirms the validity of the previously developed worm-like bead-chain hydrodynamic model...
2017: PloS One
https://www.readbyqxmd.com/read/29140677/synthesis-of-multi-au-nanoparticles-embedded-mesoporous-silica-microspheres-as-self-filtering-and-reusable-substrates-for-sers-detection
#10
Miao Chen, Wen Luo, Zhimin Zhang, Ranhao Wang, Yuqiu Zhu, Hua Yang, Xiaoqing Chen
Surface-enhanced Raman scattering (SERS) based biosensing in biological fluids is constrained by nonspecific macromolecules adsorptions and disposable property of the SERS substrate. Here, novel multi-Au nanoparticles-embedded mesoporous silica microspheres (AuNPs/mSiO2) was prepared using a one-pot method, which served as reliable substrates for SERS enhancement associated with salient features of self-filtering ability and reusability. The fabrication and physical characterization of AuNPs/mSiO2 microspheres were discussed, and SERS activity of this novel substrates was investigated by using 4-mercaptobenzoic acid (4-MBA) as Raman probe...
November 15, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/29138775/microsecond-resolved-single-molecule-fret-time-series-measurements-based-on-the-line-confocal-optical-system-combined-with-hybrid-photodetectors
#11
Hiroyuki Oikawa, Takumi Takahashi, Supawich Kamonprasertsuk, Satoshi Takahashi
Single-molecule (sm) fluorescence time series measurements based on the line confocal optical system are a powerful strategy for the investigation of the structure, dynamics, and heterogeneity of biological macromolecules. This method enables the detection of more than several thousands of fluorescence photons per millisecond from single fluorophores, implying that the potential time resolution for measurements of the fluorescence resonance energy transfer (FRET) efficiency is 10 μs. However, the necessity of using imaging photodetectors in the method limits the time resolution in the FRET efficiency measurements to approximately 100 μs...
November 15, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/29138396/polo-like-kinase-1-coordinates-biosynthesis-during-cell-cycle-progression-by-directly-activating-pentose-phosphate-pathway
#12
Xiaoyu Ma, Lin Wang, De Huang, Yunyan Li, Dongdong Yang, Tingting Li, Fudong Li, Linchong Sun, Haoran Wei, Kun He, Fazhi Yu, Debiao Zhao, Lan Hu, Songge Xing, Zhaoji Liu, Kui Li, Jing Guo, Zhenye Yang, Xin Pan, Ailing Li, Yunyu Shi, Junfeng Wang, Ping Gao, Huafeng Zhang
Two hallmarks for cancer cells are the accelerated cell cycle progression as well as the altered metabolism, however, how these changes are coordinated to optimize the growth advantage for cancer cells are still poorly understood. Here we identify that Polo-like kinase 1 (Plk1), a key regulator for cell mitosis, plays a critical role for biosynthesis in cancer cells through activating pentose phosphate pathway (PPP). We find that Plk1 interacts with and directly phosphorylates glucose-6-phosphate dehydrogenase (G6PD)...
November 15, 2017: Nature Communications
https://www.readbyqxmd.com/read/29137994/role-of-osmolytes-in-protein-folding-and-aggregation-in-cells-and-its-applications-in-biotechnology
#13
REVIEW
Gulam Rabbani
Nature has selected osmolytes to protect intracellular macromolecules against denaturing stress conditions. These molecules are accumulated in the intracellular environment at considerably high concentrations. In general, osmolytes are known to stabilize proteins. Osmolytes are small naturally occurring compound that are utilized as chemical chaperones by changing the environmental condition in diseased cellular stress state. Osmolytes are present in different organisms, including microorganisms, animals and plants...
November 11, 2017: International Journal of Biological Macromolecules
https://www.readbyqxmd.com/read/29137243/ionising-radiation-increases-permeability-of-endothelium-through-adam10-mediated-cleavage-of-ve-cadherin
#14
Sylwia Kabacik, Ken Raj
The association between ionising radiation (IR) exposure and risk of cardiovascular diseases (CVD) is well documented, but the underlying mechanism is still poorly understood. As atherosclerotic plaques are the most common cause of CVD, we investigated the effects of IR on one of the critical parameters for atherosclerotic plaque formation - endothelium permeability to macromolecules. We used endothelial cells from human coronary artery as a model of the endothelial layer. Our results show that exposure of this endothelial layer to IR increased its permeability to macromolecules of various sizes in a dose-dependent manner...
October 10, 2017: Oncotarget
https://www.readbyqxmd.com/read/29135299/oxygen-free-biochemistry-the-putative-chn-foundation-for-exotic-life-in-a-hydrocarbon-world
#15
Kong-Peng Lv, Lucy Norman, Yi-Liang Li
Since Earth's biochemistry is carbon-based and water-borne, the main strategies for searching for life elsewhere are "follow the carbon" and "follow the water." Recently, however, there is a growing focus on the prospect that putative exotic life on other planets could rely on unearthly biochemistries. Here, we hypothesize a novel oxygen-free organic chemistry for supporting potential exotic biosystems, which is named CHN biochemistry. This oxygen-free CHN biochemistry starts from simple oxygen-free species (including hydrocarbons, hydrogen cyanide, and nitriles) and produces a range of functional macromolecules that may function in similar ways to terran macromolecules, such as sugars (cyanosugars), acids (cyanoacids), amino acids (amino cyanoacids), and nucleobases (cyanonucleobases)...
November 2017: Astrobiology
https://www.readbyqxmd.com/read/29134216/multiple-interaction-regulated-phase-transition-behavior-of-thermo-responsive-copolymers-containing-cationic-poly-ionic-liquid-s
#16
Yingna Zhang, Hui Tang, Peiyi Wu
The effect of multiple interactions including anion-macromolecule interaction, water-mediated ion-macromolecule interaction and hydrophobic interaction on the phase transition behaviors of random copolymers P(OEGMA-co-BVIm[X]) comprising oligo(ethylene glycol)methacrylate (OEGMA) and imidazolium-based ionic liquids is investigated in the present study. Temperature-variable (1)H NMR and FT-IR investigations demonstrated that the hydration of CH2 side chains in P(OEGMA-co-BVIm[SCN]) was enhanced due to the anion-dipole interaction between a chaotropic anion SCN(-) and CH2 groups, and dehydration of C[double bond, length as m-dash]O groups served as the driving force of phase transition...
November 14, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/29133178/lymphatic-vasculature-in-human-dural-superior-sagittal-sinus-implications-for-neurodegenerative-proteinopathies
#17
Naomi P Visanji, Anthony E Lang, David G Munoz
Recent reports have characterized functional lymphatic vessels, which drain both fluid and immune cells from the CSF to the deep cervical lymph nodes, lining the dural sinuses in mice. If conserved in the human brain these vessels could have profound implications for neuroinflammatory and neurodegenerative diseases. We provide evidence of the presence of lymphatic vessels in human dura obtained at autopsy, at the level of the superior sagittal sinus, in 4 individuals. Immunohistochemistry for the lymphatic vessel endothelial cell marker podoplanin revealed the widespread presence of multiple structures with a distinct lumen distributed throughout the superior sagittal sinus...
November 10, 2017: Neuroscience Letters
https://www.readbyqxmd.com/read/29133086/role-of-entanglement-concentration-in-dynamic-viscoelasticity-and-film-forming-property-of-cereal-starches
#18
Li Guo
Entanglement concentration (ce, w/v) means the onset of overlap and interpenetration of random-coil chains in a macromolecule solution. The effects of ce on the dynamic viscoelasticity and film-forming property of cereal starches were investigated. The results showed that ce affected significantly the ratio of crystalline to amorphous regions of normal rice starch, waxy rice starch, normal maize starch and wheat starch because the absorbance ratio (1047cm(-1)/1022cm(-1)) increased more obviously at concentrations increasing from 0...
November 10, 2017: International Journal of Biological Macromolecules
https://www.readbyqxmd.com/read/29132296/a-fragment-based-method-for-modeling-of-protein-segments-into-cryo-em-density-maps
#19
Jochen Ismer, Alexander S Rose, Johanna K S Tiemann, Peter W Hildebrand
BACKGROUND: Single-particle analysis of electron cryo-microscopy (cryo-EM) is a key technology for elucidation of macromolecular structures. Recent technical advances in hardware and software developments significantly enhanced the resolution of cryo-EM density maps and broadened the applicability and the circle of users. To facilitate modeling of macromolecules into cryo-EM density maps, fast and easy to use methods for modeling are now demanded. RESULTS: Here we investigated and benchmarked the suitability of a classical and well established fragment-based approach for modeling of segments into cryo-EM density maps (termed FragFit)...
November 13, 2017: BMC Bioinformatics
https://www.readbyqxmd.com/read/29131633/effect-of-the-helix-coil-transition-in-bovine-skin-gelatin-on-its-associative-phase-separation-with-lysozyme
#20
Yurij A Antonov, Irina Zhuravleva, Alexander Volodine, Paula Moldenaers, Ruth Cardinaels
It is known that the formation of electrostatic polyelectrolyte complexes can induce conformational changes in the interacting macromolecules. However, the opposite effect, namely, that of the helix-coil transition of one of the interacting polyelectrolytes on its associative phase separation with another polyelectrolyte and the possible phase transitions in such systems, has not been determined. Atomic force and confocal laser scanning microscopy, phase analysis, dynamic and electrophoretic light scattering, turbidimetry, absorption, and fluorescence measurements as well as differential scanning calorimetry and rheology were used to study the effect of the helix-coil transition in bovine skin gelatin (Gel) on its associative phase separation with hen egg white lysozyme (Lys) at different temperatures (18-40 °C) and various Lys/Gel weight ratios (0...
November 13, 2017: Langmuir: the ACS Journal of Surfaces and Colloids
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