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41.
Aging exacerbates damage and delays repair of alveolar epithelia following influenza viral pneumonia
Lu Yin Dahai Zheng Gino V Limmon Nicola HN Leung Shuoyu Xu Jagath C Rajapakse Hanry Yu Vincent TK Chow Jianzhu Chen 《Respiratory research》2014,15(1)
Background
Influenza virus infection causes significantly higher levels of morbidity and mortality in the elderly. Studies have shown that impaired immunity in the elderly contributes to the increased susceptibility to influenza virus infection, however, how aging affects the lung tissue damage and repair has not been completely elucidated.Methods
Aged (16–18 months old) and young (2–3 months old) mice were infected with influenza virus intratracheally. Body weight and mortality were monitored. Different days after infection, lung sections were stained to estimate the overall lung tissue damage and for club cells, pro-SPC+ bronchiolar epithelial cells, alveolar type I and II cells to quantify their frequencies using automated image analysis algorithms.Results
Following influenza infection, aged mice lose more weight and die from otherwise sub-lethal influenza infection in young mice. Although there is no difference in damage and regeneration of club cells between the young and the aged mice, damage to alveolar type I and II cells (AT1s and AT2s) is exacerbated, and regeneration of AT2s and their precursors (pro-SPC-positive bronchiolar epithelial cells) is significantly delayed in the aged mice. We further show that oseltamivir treatment reduces virus load and lung damage, and promotes pulmonary recovery from infection in the aged mice.Conclusions
These findings show that aging increases susceptibility of the distal lung epithelium to influenza infection and delays the emergence of pro-SPC positive progenitor cells during the repair process. Our findings also shed light on possible approaches to enhance the clinical management of severe influenza pneumonia in the elderly.Electronic supplementary material
The online version of this article (doi:10.1186/s12931-014-0116-z) contains supplementary material, which is available to authorized users. 相似文献42.
43.
Chaos game representation for comparison of whole genomes 总被引:1,自引:0,他引:1
Background
Chaos game representation of genome sequences has been used for visual representation of genome sequence patterns as well as alignment-free comparisons of sequences based on oligonucleotide frequencies. However the potential of this representation for making alignment-based comparisons of whole genome sequences has not been exploited. 相似文献44.
Ruo Xu David Cole Ted Asberom Tom Bara Chad Bennett Duane A. Burnett John Clader Martin Domalski William Greenlee Lynn Hyde Hubert Josien Hongmei Li Mark McBriar Brian McKittrick Andrew T. McPhail Dmitri Pissarnitski Li Qiang Murali Rajagopalan Thavalakulamgar Sasikumar Jing Su Zhiqiang Zhao 《Bioorganic & medicinal chemistry letters》2010,20(8):2591-2596
A novel series of tricyclic γ-secretase inhibitors was designed and synthesized via a conformational analysis of literature compounds. The preliminary results have shown that compounds in this new series have much improved in vitro potency and in vivo profiles. More importantly, they have greatly reduced Notch related toxicity that was associated with previous γ-secretase inhibitors. 相似文献
45.
Negi Sushant Jaswal Gaurav Dass Kali Mazumder Koushik Elumalai Sasikumar Roy Joy K. 《Reviews in Environmental Science and Biotechnology》2020,19(2):463-488
Reviews in Environmental Science and Bio/Technology - The depletion of fossil fuel reserves and greenhouse gas emissions led to limit the use of fossil fuels, including natural gas, coal, or... 相似文献
46.
Jin YY Cheng J Yang SH Meng L Palaniyandi SA Zhao XQ Suh JW 《Bioscience, biotechnology, and biochemistry》2011,75(5):910-913
S-Adenosyl-L-methionine (SAM) is one of the major methyl donors in all living organisms. The exogenous treatment with SAM leads to increased actinorhodin production in Streptomyces coelicolor A3(2). In this study, mutants from different stages of the AfsK-AfsR signal transduction cascade were used to test the possible target of SAM. SAM had no significant effect on actinorhodin production in afsK, afsR, afsS, or actII-open reading frame 4 (ORF4) mutant. This confirms that afsK plays a critical role in delivering the signal generated by exogenous SAM. The afsK-pHJL-KN mutant did not respond to SAM, suggesting the involvement of the C-terminal of AfsK in binding with SAM. SAM increased the in vitro autophosphorylation of kinase AfsK in a dose-dependent manner, and also abolished the effect of decreased actinorhodin production by a Ser/Thr kinase inhibitor, K252a. In sum, our results suggest that SAM activates actinorhodin biosynthesis in S. coelicolor M130 by increasing the phosphorylation of protein kinase AfsK. 相似文献
47.
Sivaganesh D Saravanakumar S Sivakumar V Sasikumar S NandhaGopal J Rajajeyaganthan Ramanathan 《Luminescence》2021,36(1):99-109
A high intensity 464 nm excitable ZnWO4:Eu3+ red‐emitting phosphor for warm white lighting applications was prepared using a solid‐state reaction method by varying the dopant Eu3+ concentration. Crystalline purity and phase identification was confirmed and revealed using powder X‐ray diffraction and Rietveld refinement analysis. The surface morphology of Zn1‐xEuxWO4 (x = 0, 0.01, 0.02, 0.03, 0.04 and 0.05) was examined using scanning electron microscopy (SEM) techniques. From SEM analysis, the ZnWO4:Eu3+ phosphor prepared at 1–3% molar Eu3+ concentrations exhibited a small pebble‐like morphology with a smooth surface. On increasing the molar concentration of Eu3+ to >3%, the pebble stone morphology disappeared and a large, smooth irregular polygon‐shaped granular‐like morphology was obtained. Of the higher mol% Eu3+, the 4% Eu3+‐doped ZnWO4 showed the best photoluminescence properties with high intensity and sharp excitation at 395 and 464 nm, followed by red emission centred at 615 nm with excellent CIE coordinates (x = 0.58 and y = 0.41) in the core red region. Elemental composition and chemical state analysis were carried out for the 4% Eu3+‐doped ZnWO4 phosphor using X‐ray photoelectron spectroscopy and energy dispersive X‐ray spectroscopy studies. Based on all the above analyses, the Eu3+‐doped ZnWO4 phosphor was found to be a very efficient red‐emitting phosphor under near‐UV light as well as under visible light excitation and could be used for white LED and field emissive displays applications. 相似文献
48.
ABSTRACT: BACKGROUND: Lignin is an integral component of the plant cell wall matrix but impedes the conversion of biomass into biofuels. The plasticity of lignin biosynthesis should permit the inclusion of new compatible phenolic monomers such as flavonoids into cell wall lignins that are consequently less recalcitrant to biomass processing. In the present study, epigallocatechin gallate (EGCG) was evaluated as a potential lignin bioengineering target for rendering biomass more amenable to processing for biofuel production. RESULTS: In vitro peroxidase-catalyzed polymerization experiments revealed that both gallate and pyrogallyl (B-ring) moieties in EGCG underwent radical cross-coupling with monolignols mainly by beta--O--4-type cross-coupling, producing benzodioxane units following rearomatization reactions. Biomimetic lignification of maize cell walls with a 3:1 molar ratio of monolignols and EGCG permitted extensive alkaline delignification of cell walls (72 to 92 %) that far exceeded that for lignified controls (44 to 62 %). Alkali-insoluble residues from EGCG-lignified walls yielded up to 34 % more glucose and total sugars following enzymatic saccharification than lignified controls. CONCLUSIONS: It was found that EGCG readily copolymerized with monolignols to become integrally cross-coupled into cell wall lignins, where it greatly enhanced alkaline delignification and subsequent enzymatic saccharification. Improved delignification may be attributed to internal trapping of quinone-methide intermediates to prevent benzyl ether cross-linking of lignin to structural polysaccharides during lignification, and to the cleavage of ester intra-unit linkages within EGCG during pretreatment. Overall, our results suggest that apoplastic deposition of EGCG for incorporation into lignin would be a promising plant genetic engineering target for improving the delignification and saccharification of biomass crops. 相似文献
49.
Ehsan Vaghefi Duane TK Malcolm Marc D Jacobs Paul J Donaldson 《Biomedical engineering online》2012,11(1):1-27
Background
It has been proposed that in the absence of a blood supply, the ocular lens operates an internal microcirculation system. This system delivers nutrients, removes waste products and maintains ionic homeostasis in the lens. The microcirculation is generated by spatial differences in membrane transport properties; and previously has been modelled by an equivalent electrical circuit and solved analytically. While effective, this approach did not fully account for all the anatomical and functional complexities of the lens. To encapsulate these complexities we have created a 3D finite element computer model of the lens.Methods
Initially, we created an anatomically-correct representative mesh of the lens. We then implemented the Stokes and advective Nernst-Plank equations, in order to model the water and ion fluxes respectively. Next we complemented the model with experimentally-measured surface ionic concentrations as boundary conditions and solved it.Results
Our model calculated the standing ionic concentrations and electrical potential gradients in the lens. Furthermore, it generated vector maps of intra- and extracellular space ion and water fluxes that are proposed to circulate throughout the lens. These fields have only been measured on the surface of the lens and our calculations are the first 3D representation of their direction and magnitude in the lens.Conclusion
Values for steady state standing fields for concentration and electrical potential plus ionic and fluid fluxes calculated by our model exhibited broad agreement with observed experimental values. Our model of lens function represents a platform to integrate new experimental data as they emerge and assist us to understand how the integrated structure and function of the lens contributes to the maintenance of its transparency. 相似文献50.