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Taraknath Mandal, Ronald G Larson
Using fully atomistic and coarse-grained (CG) molecular dynamics (MD) simulations, we report, for the first time, the self-assembly of initially randomly dispersed dodecyl-β-d-maltoside (DDM) surfactants into a striped cylindrical micelle (SCM) with lamellae of surfactant heads and tails alternating along the cylindrical axis, with both heads and tails in contact with the water. By changing the interaction strength of the head group with water relative to itself, we find that such micelles are most likely for head groups with marginal solubility in the water solvent...
March 22, 2018: Soft Matter
Perali Ramu Sridhar, B C Venkatesh, Shaik Kalesha, Chalapala Sudharani
The first total synthesis of a structurally diverse mixed ligand siderophore, gobichelin B produced by Streptomyces sp. NRRL F-4415, is reported. The systematic assembly of the building blocks to synthesize Gob-B 1st half and Gob-B 2nd half and subsequent coupling of these two fragments followed by global deprotection using Pearlman's catalyst led to the isolation of gobichelin B in excellent yield and purity.
March 22, 2018: Organic & Biomolecular Chemistry
Jianchang Xu, Shuangqing Sun, Zhikun Wang, Shiyuan Peng, Songqing Hu, Lijuan Zhang
Dissipative particle dynamics (DPD) simulation is used to study the effect of pH on the morphological transition in micelles assembled from dirhamnolipids (diRLs), and analyze the pH-driven mechanism and influence factors of micellar surface patterns. At pH < 4.0, various multilayer structures with homogeneous surface patterns are observed, whereas diRLs can self-assemble into novel anisotropic morphologies with phase-separated surface patterns at pH > 7.4, such as patchy spherical micelles, rod-like micelles with helical surface patterns and a lamellar phase with anisotropic surface patterns...
March 22, 2018: Physical Chemistry Chemical Physics: PCCP
Aristeidis Papagiannopoulos, Maria Karayianni, Stergios Pispas, Aurel Radulescu
The complexation of lysozyme with aggregates from two triblock amphiphilic polyelectrolytes of the same blocks but different topologies and block molar masses, namely PS-b-SCPI-b-PEO and SCPI-b-PS-b-PEO, is investigated by scattering and spectroscopy methods. Light scattering reveals that the interaction with lysozyme causes shrinkage of the self-assembled nanoparticles in the case of the hydrophobic-polyelectrolyte-hydrophilic sequence. In the polyelectrolyte-hydrophobic-hydrophilic sequence, the opposite trend is observed...
March 22, 2018: Soft Matter
Seokho Kim, Do Hyoung Kim, Jinho Choi, Hojin Lee, Sun-Young Kim, Jung Woon Park, Dong Hyuk Park
We report the growth and nanoscale luminescence characteristics of 8-hydroxyquinolinato aluminum (Alq₃) with a crystalline hexagonal column morphology. Pristine Alq₃ nanoparticles (NPs) were prepared using a conventional reprecipitation method. Crystal hexagonal columns of Alq₃ were grown by using a surfactant-assisted self-assembly technique as an adjunct to the aforementioned reprecipitation method. The formation and structural properties of the crystalline and non-crystalline Alq₃ NPs were analyzed with scanning electron microscopy and X-ray diffraction...
March 22, 2018: Materials
Elena Khazina, Oliver Weichenrieder
LINE-1 (L1) is an autonomous retrotransposon, which acted throughout mammalian evolution and keeps contributing to human genotypic diversity, genetic disease and cancer. L1 encodes two essential proteins: L1ORF1p, a unique RNA-binding protein, and L1ORF2p, an endonuclease and reverse transcriptase. L1ORF1p contains an essential, but rapidly evolving N-terminal portion, homo-trimerizes via a coiled coil and packages L1RNA into large assemblies. Here, we determined crystal structures of the entire coiled coil domain of human L1ORF1p...
March 22, 2018: ELife
Lu Xu, Gordon Bosiljevac, Kyle Yu, Yi Y Zuo
Langmuir monolayer self-assembled at the air-water interface represents an excellent model for studying phase transition and lipid polymorphism in two dimensions. Compared to numerous studies of phospholipid phase transitions induced by isothermal compression, there are very scarce reports on two-dimensional phase transitions induced by isobaric heating. This is mainly due to technical difficulties of continuously regulating temperature variations while maintaining a constant surface pressure in a classical Langmuir-type film balance...
March 22, 2018: Langmuir: the ACS Journal of Surfaces and Colloids
Ravit Malishev, Razan Abbasi, Raz Jelinek, Liraz Chai
Biofilms are aggregates of cells that form surface-associated communities. The cells in a biofilm are interconnected with an extracellular matrix, a network that is made mostly of polysaccharides, proteins and sometimes nucleic acids. Some extracellular matrix proteins form fibers, often termed functional amyloids or amyloid-like fibrils, to differentiate their constructive function from disease-related amyloid fibers. Recent studies of functional amyloid assembly have neglected their interaction with membranes, despite their native assembly in a cellular environment...
March 22, 2018: Biochemistry
Izar Capel Berdiell, Stuart L Warriner, Malcolm A Halcrow
Silver(i) complexes of 2,4,6-tri(pyrazol-1-yl)pyridine (tpp), 2,4,6-tri(pyrazol-1-yl)pyrimidine (tpym), 2,4,6-tri(pyrazol-1-yl)-1,3,5-triazine (tpt) and 2,4-di(pyrazol-1-yl)-1,3,5-triazine (bpt) are reported. Dinuclear [Ag2(μ-tpp)2(MeCN)2][BF4]2·2MeCN and [Ag2(μ-tpym)2(MeCN)2][BF4]2 are formed from approximately planar [AgL(NCMe)]+ (L = tpp or bpym) centres, which dimerise via apical interactions to the pendant pyrazolyl donor on each ligand. Two polymeric solvatomorph phases [Ag2(μ-tpp)2][BF4]2·nMeNO2 were obtained by crystallising AgBF4 and tpp from nitromethane solution...
March 22, 2018: Dalton Transactions: An International Journal of Inorganic Chemistry
Jasmin C Athas, Catherine P Nguyen, Shailaa Kummar, Srinivasa R Raghavan
The spontaneous folding of flat gel films into tubes is an interesting example of self-assembly. Typically, a rectangular film folds along its short axis when forming a tube; folding along the long axis has been seen only in rare instances when the film is constrained. Here, we report a case where the same free-swelling gel film folds along either its long or short axis depending on the concentration of a solute. Our gels are sandwiches (bilayers) of two layers: a passive layer of cross-linked N,N'-dimethylyacrylamide (DMAA) and an active layer of cross-linked DMAA that also contains chains of the biopolymer alginate...
March 22, 2018: Soft Matter
Srinivas Mushnoori, Kassandra Schmidt, Vikas Nanda, Meenakshi Dutt
Harnessing the self-assembly of peptide sequences has demonstrated great promise in the domain of creating high precision shape-tunable biomaterials. The unique properties of peptides allow for a building block approach to material design. In this study, self-assembly of mixed systems encompassing two peptide sequences with identical hydrophobic regions and distinct polar segments is investigated. The two peptide sequences are diphenylalanine and phenylalanine-asparagine-phenylalanine. The study examines the impact of molecular composition (namely, the total peptide concentration and the relative tripeptide concentration) on the morphology of the self-assembled hybrid biological material...
March 22, 2018: Organic & Biomolecular Chemistry
Achim Link, Christof Sparr
While aromatic hydrocarbons are ubiquitous in organic chemistry, they are typically not associated with chirality and stereoisomerism. Due to the planarity and symmetry of simple arenes, methods to assemble aromatic rings are not routinely considered for the stereoselective synthesis of chiral compounds. The aim of this tutorial review is to contrast this common perception with the counterintuitive circumstance that stereoselective arene formation offers a means to stereoselectively prepare an exceptional range of chiral aromatic structures...
March 22, 2018: Chemical Society Reviews
Bohui Xu, Yan Xu, Gaoxing Su, Hongyan Zhu, Li Zong
Successful delivery of small interfering RNA (siRNA) into the cytoplasm of target cells relies on biocompatible and efficient vectors. In this study, a novel multifunctional core/shell nanoparticle [CS-SS-9R/BSA-c(RGDyK)] was developed to effectively deliver siVEGF to hepatocellular carcinoma cells (Bel-7402 cells). To improve the gene payload and transfection efficiency, a positively charged inner core (CS-SS-9R) was constructed by grafting nona-arginine (9R) onto chitosan (CS) using disulfide bonds. The negatively charged outer shell [BSA-c(RGDyK)] assembled on the surface of inner core by electrostatic forces that shielded high cationic charges and provided improved targeting...
March 22, 2018: Journal of Drug Targeting
Jia-Li Liu, Zhi-Ling Tang, Jia-Qi Zhang, Yaqin Chai, Ying Zhuo, Ruo Yuan
The electrochemiluminescence (ECL) properties of polycyclic aromatic hydrocarbons (PAHs) are excellent on account of the high photoluminescence quantum yield. However, the poor solubility and radical instability of PAHs in the aqueous solution severely restricted the further biological application. Here, 9,10 - diphenylanthracene (DPA) nano blocks (NBs) with good dispersibility and stability in aqueous solution were prepared according to morphology-controlled technology employing water-soluble polymers as a protectant...
March 22, 2018: Analytical Chemistry
Matthaeus Schwarz-Schilling, Aurore Dupin, Fabio Chizzolini, Swati Krishnan, Sheref Mansy, Friedrich C Simmel
Molecular complexes composed of RNA molecules and proteins are promising multifunctional nanostructures for a wide variety of applications in biological cells or in artificial cellular systems. In this study, we systematically address some of the challenges associated with the expression and assembly of such hybrid structures using cell-free gene expression systems. As a model structure, we investigated a pRNA-derived RNA scaffold functionalized with four distinct aptamers, three of which bind to proteins - streptavidin and two fluorescent proteins - while one binds the small molecule dye malachite green (MG)...
March 22, 2018: Nano Letters
Mei-Chun Chen, Wan-Yu Chen, Wan-Yu Tsui, Guey-Ling Chang, Ming-Ying Hong
BACKGROUND & PROBLEMS: The return-to-treatment rate is an important indicator of treatment outcome and care effectiveness in cancer patients. The return-to-treatment rates for patients at National Taiwan University Hospital (NTUH) in 2011 and 2012 were 38.5% and 33.3%, respectively. In order to improve the quality of care that is provided to patients, we reviewed NTUH's current clinical case management protocols for handling patients who refused treatment and then identified and resolved the potential problems in these protocols...
April 2018: Hu Li za Zhi the Journal of Nursing
Dustin C Hancks
Chromothripsis is a mutational event driven by tens to hundreds of double-stranded DNA breaks which occur in a single event between a limited number of chromosomes. Following chromosomal shattering, DNA fragments are stitched together in a seemingly random manner resulting in complex genomic rearrangements including sequence shuffling, deletions, and inversions of varying size. This genomic catastrophe has been observed in cancer genomes and the genomes of patients harboring developmental and congenital defects...
2018: Methods in Molecular Biology
Yuanli Luo, Daiwen Dong, Yu Su, Xuyi Wang, Yumei Peng, Jiang Peng, Changyong Zhou
Mustard clubroot, caused by Plasmodiophora brassicae, is a serious disease that affects Brassica juncea var. tumida Tsen, a mustard plant that is the raw material for a traditional fermented food manufactured in Chongqing, China. In our laboratory, we screened the antagonistic bacteria Zhihengliuella aestuarii against P. brassicae. To better understand the biocontrol mechanism, three transcriptome analyses of B. juncea var. tumida Tsen were conducted using Illumina HiSeq 4000, one from B. juncea only inoculated with P...
March 22, 2018: Functional & Integrative Genomics
Chaoyang Chen, Chongran Sun, Yi-Rui Wu
A wild-type solventogenic strain Clostridium diolis WST, isolated from mangrove sediments, was characterized to produce high amount of butanol and acetone with negligible level of ethanol and acids from glucose via a unique acetone-butanol (AB) fermentation pathway. Through the genomic sequencing, the assembled draft genome of strain WST is calculated to be 5.85 Mb with a GC content of 29.69% and contains 5263 genes that contribute to the annotation of 5049 protein-coding sequences. Within these annotated genes, the butanol dehydrogenase gene (bdh) was determined to be in a higher amount from strain WST compared to other Clostridial strains, which is positively related to its high-efficient production of butanol...
March 21, 2018: Current Microbiology
Sean F Gilmore, Timothy S Carpenter, Helgi I Ingólfsson, Sandra K G Peters, Paul T Henderson, Craig D Blanchette, Nicholas O Fischer
Nanolipoprotein particles (NLPs) are reconstituted high-density lipoproteins, consisting of a phospholipid bilayer stabilized by an apolipoprotein scaffold protein. This class of nanoparticle has been a vital tool in the study of membrane proteins, and in recent years has been increasingly used for in vivo applications. Previous work demonstrated that the composition of the lipid bilayer component affects the stability of these particles in serum solutions. In the current study, NLPs assembled with phosphatidylcholine lipids featuring different acyl chain structures were systematically tested to understand the effect that lipid composition has on NLP stability in both neat serum and cell culture media supplemented with 10% serum by volume...
March 22, 2018: Nanoscale
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