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71.
72.
Seong Ji Woo Youngmi Kim Harry Jung Jae Jun Lee Ji Young Hong 《International journal of molecular sciences》2022,23(6)
Extracellular matrix production by pleural mesothelial cells in response to Mycobacterium tuberculosis contributes to tuberculous fibrosis. NOX4 is involved in the pathogenesis of tuberculous fibrosis. In this study, we evaluated whether NOX4 gene-targeting microRNAs showed protective effects in tuberculosis fibrosis. TargetScan prediction software was used to identify candidate microRNAs that bind the 3′ UTRs of NOX4, and microRNA-148a (miR-148a) was selected as the best miRNA candidate. A repressed and forced expression assay in Met5A cells was performed to investigate the causal relationship between miR-148a and NOX4. The role of miR-148a in tuberculous pleural fibrosis was studied using a murine model of Mycobacterium bovis bacillus Calmette–Guérin (BCG) pleural infection. Heat-killed M. tuberculosis (HKMT) induces NOX4 and POLDIP2 expression. We demonstrated the inhibitory effect of miR-148a on NOX4 and POLDIP2 expression. The increased expression of miR-148a suppressed HKMT-induced collagen-1A synthesis in PMC cells. In the BCG pleurisy model, miR-148a significantly reduced fibrogenesis and epithelial mesenchymal transition. High levels of miR-148a in tuberculous pleural effusion can be interpreted as a self-limiting homeostatic response. Our data indicate that miR-148a may protect against tuberculous pleural fibrosis by regulating NOX4 and POLDIP2. 相似文献
73.
Afroditi Kastrenopoulou Kyriakos E. Kypreos Nicholaos I. Papachristou Stavros Georgopoulos Ioulia Mastora Ioanna Papadimitriou-Olivgeri Argyro Spentzopoulou Dragana Nikitovic Vassilios Kontogeorgakos Harry C. Blair Dionysios J. Papachristou 《International journal of molecular sciences》2022,23(9)
In the present study, we studied the effect of apolipoprotein A-1 (APOA1) on the spatial and molecular characteristics of bone marrow adipocytes, using well-characterized ApoA1 knockout mice. APOA1 is a central regulator of high-density lipoprotein cholesterol (HDL-C) metabolism, and thus HDL; our recent work showed that deficiency of APOA1 increases bone marrow adiposity in mice. We found that ApoA1 deficient mice have greatly elevated adipocytes within their bone marrow compared to wild type counterparts. Morphologically, the increased adipocytes were similar to white adipocytes, and displayed proximal tibial-end localization. Marrow adipocytes from wild type mice were significantly fewer and did not display a bone-end distribution pattern. The mRNA levels of the brown/beige adipocyte-specific markers Ucp1, Dio2, Pat2, and Pgc1a; and the expression of leptin were greatly reduced in the ApoA1 knock-out in comparison to the wild-type mice. In the knock-out mice, adiponectin was remarkably elevated. In keeping with the close ties of hematopoietic stem cells and marrow adipocytes, using flow cytometry we found that the elevated adiposity in the ApoA1 knockout mice is associated with a significant reduction in the compartments of hematopoietic stem cells and common myeloid, but not of the common lymphoid, progenitors. Moreover, the ‘beiging’-related marker osteopontin and the angiogenic factor VEGF were also reduced in the ApoA1 knock-out mice, further supporting the notion that APOA1—and most probably HDL-C—regulate bone marrow microenvironment, favoring beige/brown adipocyte characteristics. 相似文献
74.
M. E. Henry Bergmann Tatiana Iourtchouk Johanna Rollin 《Journal of Applied Electrochemistry》2011,41(9):1109-1123
Bromide electrolysis was carried out on laboratory-scale cells in the range of 1–1,005 mg [Br−] dm−3 using boron-doped diamond (BDD) anodes. These studies were part of fundamental research activities on drinking water electrolysis
for disinfection. Synthetic water systems were mostly used in the experiments, which varied the temperature between 5 and
30 °C, the current density between 50 and 700 A m−2, and the rotation rate of the rotating anode between 100 and 500 rpm (laminar regime). Hypobromite and bromate were found
as by-products, as expected. Bromite was not detected. Higher bromate levels were formed at higher current density, but no
clear relationship was observed between bromate concentration and the rotation rate or temperatures between 5 and 30 °C. Bromate
yields higher than 90% were found at higher charge passed. Perbromate was found as a new potential synthesis or disinfection
by-product (DBP), but no perbromate was detected at the lowest bromide concentrations and under drinking water conditions.
The perbromate yield was about 1%, and somewhat lower when bromate was used as a starting material instead of bromide. At
a temperature of 5 °C more perbromate was detected compared with experiments at 20°. Approximately 20 times more perchlorate
was formed compared with perbromate formation in the presence of chloride ions of equimolar concentration. State of mechanistic
considerations is presented and a mechanism for perbromate formation is proposed. The reaction from bromate to perbromate
was found to be limited that is in contrast to the earlier studied chlorate-to-perchlorate conversion. In the measured concentration
range, reduction processes at the mixed oxide cathode showed a much higher impact on the resulting concentration for perbromate
than for bromate. 相似文献
75.
76.
The rotational isomeric state model was employed to provide a better understanding of the role of chain microstructure on the conformational behavior of homogeneous ethylene-1-olefin copolymers. The chain microstructure was assembled in accordance with the copolymerization theory using a set of conditional probabilities in direct relation to the reactivity ratios and the feed compositions of the comonomers. The catalytic inversion influence on the tacticity of the polymeric microstructure was also taken into account by considering the replication probability during the Monte Carlo simulation. Statistical weight factors of the rotational isomeric states were evaluated using molecular dynamics runs of the various homopolymers according to the earlier work of Mattice et al. Probability distribution surfaces constructed by the integration of the molecular dynamics trajectories of sufficient length to sample all of the conformational space indicated the increase of the probability of g±t joint states at the expense of g±g± pairs with the increase in the side chain length of the 1-olefin comonomers. It was also indicated that this behavior had a maximum around poly(1-butene)/poly(1-hexene) with an apparent reversal in case of poly(1-octene) due to the side chain crowding, which forces the chain to favor more of the g±g± joint states. The characteristic ratios calculated for the copolymers on the basis of the rotational isomeric state model also indicated the increased extension of the polymer backbone with the increase in the side chain length. The lower characteristic ratio calculated for the octene polymers may, in fact, explain the experimental observation that poly(1-octene) has a lower melting point than those of other poly(1-olefin)s of shorter side chains. A complete account of the role of tacticity on the characteristic ratio and the radial distribution function is also given. 相似文献
77.
This paper presents further results and extensions of our previous point defect model for time-dependent growth of passive oxide films on metal surfaces. Specifically, by accounting for vacancies as material species rather than just holes in the oxide lattice, the model incorporates more plausible expressions for interfacial reactions and associated kinetic rate expressions. We use the model to explore the general effects of varying metal valence and electrolyte pH on passive film growth. Furthermore, we examine key assumptions concerning the thickness dependence of the electric field within the film. When the electric field inside the film remains constant and the rate constant for oxygen vacancy production varies with applied potential, the model predicts trends in thickness versus potential in reasonable agreement with experimental data for a variety of metal/metal oxide systems. This represents a considerable improvement upon the previous ‘high-field’ form of the model which assumed rate constants independent of potential and electric field in the film varying with thickness. 相似文献
78.
Daniela Boettger Holger Bergmann Barbara Kuehn Dr. Ekaterina Shelest Prof. Dr. Christian Hertweck 《Chembiochem : a European journal of chemical biology》2012,13(16):2363-2373
Fungal hybrid enzymes consisting of a polyketide synthase (PKS) and a nonribosomal peptide synthetase (NRPS) module are involved in the biosynthesis of a vast array of ecologically and medicinally relevant natural products. Whereas a dozen gene clusters could be assigned to the requisite PKS–NRPS pathways, the programming of the multifunctional enzymes is still enigmatic. Through engineering and heterologously expressing a chimera of PKS (lovastatin synthase, LovB) and NRPS (cytochalasin synthase, CheA) in Aspergillus terreus, we noted the potential incompatibility of a fungal highly reducing PKS (hrPKS) with the NRPS component of fungal PKS–NRPS hybrids. To rationalize the unexpected outcome of the gene fusion experiments, we conducted extensive bioinformatic analyses of fungal PKS–NRPS hybrids and LovB‐type PKS. From motif studies and the function of the engineered chimeras, a noncanonical function of C‐terminal condensation (C) domains in truncated PKS–NRPS homologues was inferred. More importantly, sequence alignments and phylogenetic trees revealed an evolutionary imprint of the PKS–NRPS domains, which reflect the evolutionary history of the entire megasynthase. Furthermore, a detailed investigation of C and adenylation (A) domains provides support for a scenario in which not only the A domain but also the C domain participates in amino acid selection. These findings shed new light on the complex code of this emerging class of multifunctional enzymes and will greatly facilitate future combinatorial biosynthesis and pathway engineering approaches towards natural product analogues. 相似文献
79.
A number of polyphosphazenes with negatively charged β‐alanine (β‐Ala) and γ‐amino butyric acid (GABA) side groups were synthesized and studied for their ability to initiate the growth of hydroxyapatite (HAp) during exposure to simulated body fluid (SBF). All the polymers were hydrolytically sensitive, with the final hydrolysis rate dependent on the specific active side groups (GABA > β‐Ala). These systems also underwent extensive mineralization, with calcium phosphate deposited across their entire surface during exposure to SBF (up to 115 wt % gain after 4 weeks). This degree of deposition is a major advance over previously reported polyphosphazene systems, which underwent a maximum of 27 wt % gain after immersion in SBF for 4 weeks. The extent of mineralization over the surface was monitored using environmental scanning electron microscopy (ESEM) coupled with energy dispersive X‐ray spectroscopy (EDS). In addition, X‐ray diffraction (XRD) was used to determine the identity of the mineralized material. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41741. 相似文献
80.
Dr. Thomas Hauch Fenger Prof. Dr. Harry Brumer 《Chembiochem : a European journal of chemical biology》2015,16(4):575-583
A series of N‐bromoacetylglycosylamines and bromoketone C‐glycosides were synthesised from complex xyloglucan oligosaccharide (XyGO) scaffolds as specific active‐site affinity labels for endo‐xyloglucanases. Compounds based on XXXG (Xyl3Glc4) and XLLG (Xyl3Glc4Gal2) oligosaccharides exhibited strikingly higher affinities and higher rates of irreversible inhibition than known cellobiosyl and new lactosyl disaccharide congeners when tested with endo‐xyloglucanases from two distinct glycoside hydrolase (GH) families. Intact‐protein mass spectrometry indicated that inactivation with XyGO derivatives generally resulted in a 1:1 labelling stoichiometry. Together, these results indicate that XyGO‐based affinity reagents have significant potential as inhibitors and proteomic reagents for the identification and analysis of diverse xyloglucan‐active enzymes in nature, to facilitate industrial enzyme applications. 相似文献