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Mohamed Naguib, Tara L Schiller, Daniel J Keddie
The synthesis of a range of alkyl esters (methyl, n-butyl, and n-decyl) prepared via Steglich esterification of the thermodynamically controlled exo, exo Diels-Alder adduct of furfuryl alcohol and maleic anhydride is reported. Subsequent ring-opening metathesis polymerization of these bio-derivable tricyclic oxanorbornene analogs delivers polymers with targeted molar mass and low molar mass dispersity. The polymerizations are rapid with complete monomer conversion achieved within 15 min. Significantly, the presence of the cyclic lactone at the bridgehead of these monomers leads to polymers with high regioregularity (>85% head-to-tail) and high stereoregularity (>75% trans)...
January 15, 2018: Macromolecular Rapid Communications
Hiroyuki Suga, Taichi Iwai, Masahiro Shimizu, Kie Takahashi, Yasunori Toda
An efficient method for the generation of an oxidopyrylium ylide from 6-acetoxy-6-acetoxymethyl-2H-pyran-3(6H)-one using a Pd catalyst and [5+2] cycloadditions of the resulting ylide are described. Among substituted styrene derivatives as dipolarophiles, electron-rich styrenes showed higher yield (up to 80%). The [5+2] cycloaddition reactions can also be applied to exo-methylene cyclic compounds, and an improved method for the synthesis of polygalolide intermediate has been demonstrated.
January 15, 2018: Chemical Communications: Chem Comm
Shao-Hua Wu, Biao Zhang, Fang-Fang Wang, Zhen-Zhen Mi, Jian-Jun Sun
A sensitive and selective electrochemical Hg2+ sensor was developed based on T-Hg2+-T structure and exonuclease (Exo) III -assisted target recycling amplification at heated gold disk electrode (HAuDE). First, a DNA signal probe P1 was for the first time designed and labeled with ferrocene (Fc) near the attached SH-5'-end, so as to shorten the distance between Fc and the electrode and enhance the initial current of Fc compared with that labeled at the 3'-end far from the electrode. Then the signal amplification was achieved by Exo III-assisted Hg2+ recycling...
January 5, 2018: Biosensors & Bioelectronics
D Marques, A Miranda, A G Silva, P R T Munro, P A A DE Beule
Some implementations of interference microscopy imaging use digital holographic measurements of complex scattered fields to reconstruct three-dimensional refractive index maps of weakly scattering, semi-transparent objects, frequently encountered in biological investigations. Reconstruction occurs through application of the object scattering potential which assumes an isotropic refractive index throughout the object. Here, we demonstrate that this assumption can in some circumstances be invalid for biological imaging due to the presence of lipid-induced optical anisotropy...
January 11, 2018: Journal of Microscopy
Thomas Friedrich Fässler, Felix Geitner, Christoph Wallach
The reaction of [(Ge9{Si(TMS)3}2PtBu2)]- with NHCMesCuCl yields [(Ge9{Si(TMS)3}2)(tBu2P)]Cu(NHCMes) (1), which is a new derivative of the recently reported monomeric zwitterionic tetrel cluster compounds [(Ge9{Si(TMS)3}2)(tBu2P)]M(NHCDipp) (M: Cu, Ag, Au). By contrast, the reaction of the same anion [(Ge9{Si(TMS)3}2PtBu2)]- with the more labile copper phosphine complex Cy3PCuCl leads to the formation of [Ge9{Si(TMS)3}2{(tBu)2PCu}2Ge9{Si(TMS)3}2] (2) which is a neutral dimeric twofold-bridged [Ge9] cluster compound, with the exo-bonded phosphine substituent being involved in the cluster bridging...
January 11, 2018: Chemistry: a European Journal
Hisashi Yagi, Asako Fujise, Narumi Itabashi, Takashi Ohshiro
Alginate, which is an anionic polysaccharide, is widely distributed in the cell wall of brown algae. Alginate and the products of its degradation (oligosaccharides) are used in stabilizers, thickeners, and gelling agents, especially in the food industry. The degradation of alginate generally involves a combination of several alginate lyases (exo-type, endo-type, and oligoalginate lyase). Enhancing the efficiency of the production of alginate degradation products may require the identification of novel alginate lyases with unique characteristics...
January 8, 2018: Journal of Biochemistry
Kenji Hagiwara, Kana Kurihara, Masakazu Honma, Junichiro Yamamoto, Fumikazu Shinohara
Nucleic acid medicine is the next-generation therapeutic modality for refractory diseases with its unique mode of action as an alternative to traditional therapies. A nucleic acid delivery system targeted to liver was validated clinically; however, the delivery system of nucleic acids targeting solid tumors following systemic administration is not efficient enough for clinical use. In this study, we first utilized an antisense oligonucleotide (ASO) and polyethylene glycol (PEG) in one-to-one conjugation (PEG-ASO) at the endo-position of the ASO (endo-PEG-ASO)...
January 10, 2018: Journal of Biomaterials Science. Polymer Edition
Masato Harada, Shuma Kato, Ryosuke Haraguchi, Shin-Ichi Fukuzawa
The Cu(MeCN)4PF6/DTBM-Segphos complex catalyzed the highly diastereo- and enantioselective 1,3-dipolar cycloaddition of azomethine ylides with benzo[b]thiophene sulfones with the usual regiochemistry to give single isomers of the exo-cycloadducts in good yields. In contrast, the AgOAc/ThioClickFerrophos complex catalyzed the reaction with atypical regiochemistry to give the endo-cycloadducts as major products with excellent enantioselectivities. Thus, the choice of chiral metal complex enabled the regio- and stereoselective synthesis of chiral fused sulfolanes...
January 9, 2018: Chemistry: a European Journal
Romain Duvert, Sarah Gebeile-Chauty
INTRODUCTION: Replacing impression by intraoral camera is a paradigm shift. However no in vivo independent studies have compared the accuracy of analog impressions with three systems of digital impression. Are digital recordings precise enough for our orthodontic practices? MATERIALS AND METHODS: Five impressions of the maxillary and mandibular arch of the same subject were conducted in vinylpolysiloxane, cast in plaster type IV then scanned by a laboratory scanner (VPS group)...
December 2017: L' Orthodontie Française
Peter Redder
Correct balance between bacterial RNA degradation and synthesis is essential for controlling expression level of all RNAs. The RNA polymerase, which performs the RNA synthesis, is highly conserved across the bacterial domain. However, this is surprisingly not the case for the RNA degradation machinery, which is composed of different subunits and performs different enzymatic reactions, depending on the organism. In Escherichia coli, the RNA decay is performed by the degradosome complex, which forms around the membrane-associated endoribonuclease RNase E, and is stable enough to be purified without falling apart...
January 5, 2018: Wiley Interdisciplinary Reviews. RNA
Tomasz Bogiel, Aleksander Deptuła, Joanna Kwiecińska-Piróg, Małgorzata Prażyńska, Agnieszka Mikucka, Eugenia Gospodarek-Komkowska
Pseudomonas aeruginosa rods are one of the most commonly isolated microorganisms from clinical specimens, usually responsible for nosocomial infections. Antibiotic-resistant P. aeruginosa strains may present reduced expression of virulence factors. This fact may be caused by appropriate genome management to adapt to changing conditions of the hospital environment. Virulence factors genes may be replaced by those crucial to survive, like antimicrobial resistance genes. The aim of this study was to evaluate, using PCR, the occurrence of exoenzyme S-coding gene (exoS) in two distinct groups of P...
December 4, 2017: Polish Journal of Microbiology
Ting-Lei Tao, Feng-Jie Cui, Xiao-Xiao Chen, Wen-Jing Sun, Da-Ming Huang, Jinsong Zhang, Yan Yang, Di Wu, Wei-Min Liu
BACKGROUND: Mushroom showed pellet, clump and/or filamentous mycelial morphologies during submerged fermentation. Addition of microparticles including Talc (magnesium silicate), aluminum oxide and titanium oxide could control mycelial morphologies to improve mycelia growth and secondary metabolites production. Here, effect of microparticle Talc (45 μm) addition on the mycelial morphology, fermentation performance, monosaccharide compositions of polysaccharides and enzymes activities associated with polysaccharide synthesis in G...
January 6, 2018: Microbial Cell Factories
Yudie Sun, Pai Peng, Ruiyan Guo, Huihui Wang, Tao Li
A variety of nucleic acid amplification techniques have been integrated into different detection methods to promote the development of sensitive and convenient analysis of nucleic acids. However, it is still in urgent need to develop amplified nucleic acid biosensors for the analysis of susceptible gene and even distinguishing single-base mismatched DNA in complex biological samples. Benefiting from the achieved detection strategies, here we boost isothermal nucleic acid amplification by resorting to enzyme amplification, and combine this two-stage amplification method with surface-enhanced Raman spectroscopy (SERS) to develop a signal-on nucleic acid detection platform...
December 29, 2017: Biosensors & Bioelectronics
Pietro Ridone, Stephan L Grage, Amrutha Patkunarajah, Andrew R Battle, Anne S Ulrich, Boris Martinac
The level of fatty acid saturation in phospholipids is a crucial determinant of the biophysical properties of the lipid bilayer. Integral membrane proteins are sensitive to changes of their bilayer environment such that their activities and localization can be profoundly affected. When incorporated into phospholipids of mammalian cells, poly-unsaturated fatty acids (PUFAs) determine the mechanical properties of the bilayer thereby affecting several membrane-associated functions such as endo- and exo-cytosis and ion channel/membrane receptor signalling cascades...
December 28, 2017: Journal of the Mechanical Behavior of Biomedical Materials
Michael L Newell, Gareth A Wallis, Angus M Hunter, Kevin D Tipton, Stuart D R Galloway
Carbohydrate (CHO) ingestion during exercise lasting less than three hours improves endurance exercise performance but there is still debate about the optimal dose. We utilised stable isotopes and blood metabolite profiles to further examine metabolic responses to CHO (glucose only) ingestion in the 20-64 g·h-1 range, and to determine the association with performance outcome. In a double-blind, randomized cross-over design, male cyclists (n = 20, mean ± SD, age 34 ± 10 years, mass 75.8 ± 9 kg, peak power output 394 ± 36 W, VO2max 62 ± 9 mL·kg-1·min-1) completed four main experimental trials...
January 3, 2018: Nutrients
Kang Zhang, Yunjun Shen, Jiyong Liu, Bernhard Spingler, Simon Duttwyler
The crystal structure of the deprotonated monocarba-closo-dodecaborate [12-CN-CB11H11]- is reported. This dianion, featuring a delocalized endohedral negative charge and an exo-cluster C-[Li] moiety, was used for the synthesis of ditopic ligands with the potential to form novel supramolecular frameworks.
January 4, 2018: Chemical Communications: Chem Comm
Nakanori Fujii, Hiroshi Hirata, Koji Ueno, Junichi Mori, Shintaro Oka, Kosuke Shimizu, Yoshihisa Kawai, Ryo Inoue, Yoshiaki Yamamoto, Hiroaki Matsumoto, Tomoyuki Shimabukuro, Koichi Udoh, Yoshinobu Hoshii, Rajvir Dahiya, Hideyasu Matsuyama
Exosome-miRNAs (exo-miR) have recently been identified as modulators of cancer progression and distant metastasis. We previously found that intracellular miR-224 is up-regulated and significantly related to cancer invasion and metastasis in clear cell renal cell carcinoma (ccRCC). We therefore investigated the role of exosome miR-224 in ccRCC and explored the interaction between intra- and extracellular miR-224 in renal cell carcinoma. To validate the method for isolating exosomes from blood samples or cell culture media, we examined exosome morphology using transmission electron microscope (TEM)...
December 15, 2017: Oncotarget
Elise E B LaDouceur, Brian G Murphy
Microsporidia are a diverse, parasitic phylum closely related to fungi. They infect a broad range of host species and tissues. This report describes microsporidiosis infection in a captive, wild-caught peppermint shrimp ( Lysmata spp.). The animal was found dead in its enclosure approximately 5 days after molting. Grossly, the skeletal musculature was diffusely swollen, opaque, and pale tan to white. Histologically, skeletal myofibers were replaced by large aggregates of sporophorous vesicles containing up to eight spores and earlier stages of sporogony...
December 2017: Journal of Zoo and Wildlife Medicine: Official Publication of the American Association of Zoo Veterinarians
Jean L Tan, Sin N Lau, Bryan Leaw, Hong P T Nguyen, Lois A Salamonsen, Mohamed I Saad, Siow T Chan, Dandan Zhu, Mirja Krause, Carla Kim, William Sievert, Euan M Wallace, Rebecca Lim
Idiopathic pulmonary fibrosis (IPF) is characterized by chronic inflammation, severe scarring, and stem cell senescence. Stem cell-based therapies modulate inflammatory and fibrogenic pathways by release of soluble factors. Stem cell-derived extracellular vesicles should be explored as a potential therapy for IPF. Human amnion epithelial cell-derived exosomes (hAEC Exo) were isolated and compared against human lung fibroblasts exosomes. hAEC Exo were assessed as a potential therapy for lung fibrosis. Exosomes were isolated and evaluated for their protein and miRNA cargo...
January 3, 2018: Stem Cells Translational Medicine
Amine Meliani, Florence Boisgerault, Zachary Fitzpatrick, Solenne Marmier, Christian Leborgne, Fanny Collaud, Marcelo Simon Sola, Severine Charles, Giuseppe Ronzitti, Alban Vignaud, Laetitia van Wittenberghe, Beatrice Marolleau, Fabienne Jouen, Sisareuth Tan, Olivier Boyer, Olivier Christophe, Alain R Brisson, Casey A Maguire, Federico Mingozzi
Results from clinical trials of liver gene transfer for hemophilia demonstrate the potential of the adeno-associated virus (AAV) vector platform. However, to achieve therapeutic transgene expression, in some cases high vector doses are required, which are associated with a higher risk of triggering anti-capsid cytotoxic T-cell responses. Additionally, anti-AAV preexisting immunity can prevent liver transduction even at low neutralizing antibody (NAb) titers. Here, we describe the use of exosome-associated AAV (exo-AAV) vectors as a robust liver gene delivery system that allows the therapeutic vector dose to be decreased while protecting from preexisting humoral immunity to the capsid...
October 24, 2017: Blood Advances
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