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The pyrrolysyl-tRNA synthetase (PylRS) facilitates the cotranslational installation of the 22nd amino acid pyrrolysine. Owing to its tolerance for diverse amino acid substrates, and its orthogonality in multiple organisms, PylRS has emerged as a major route to install noncanonical amino acids into proteins in living cells. Recently, a novel class of PylRS enzymes was identified in a subset of methanogenic archaea. Enzymes within this class (ΔPylSn) lack the N-terminal tRNA-binding domain that is widely conserved amongst PylRS enzymes, yet remain active and orthogonal in bacteria and eukaryotes. In this study, we use biochemical and in vivo UAG-readthrough assays to characterize the aminoacylation efficiency and substrate spectrum of a ΔPylSn class PylRS from the archaeon Candidatus Methanomethylophilus alvus. We show that, compared with the full-length enzyme from Methanosarcina mazei, the Ca. M. alvus PylRS displays reduced aminoacylation efficiency but an expanded amino acid substrate spectrum. To gain insight into the evolution of ΔPylSn enzymes, we performed molecular phylogeny using 156 PylRS and 105 pyrrolysine tRNA (tRNAPyl) sequences from diverse archaea and bacteria. This analysis suggests that the PylRS.tRNAPyl pair diverged before the evolution of the three domains of life, placing an early limit on the evolution of the Pyl-decoding trait. Furthermore, our results document the coevolutionary history of PylRS and tRNAPyl and reveal the emergence of tRNAPyl sequences with unique A73 and U73 discriminator bases. The orthogonality of these tRNAPyl species with the more common G73-containing tRNAPyl will enable future efforts to engineer PylRS systems for further genetic code expansion. [ABSTRACT FROM AUTHOR]

Multi-energy complementary power generation mode has become the theme of modern power grid construction. In response to the requirements of the national multi-energy strategy, the operation mode of hydropower units will inevitably change frequently, resulting in unpredictable hydraulic unstable flow phenomena (such as the blade passage vortex, the vortex rope in the draft tube, etc.) which will reduce the hydraulic performance of units and may lead to strong vibration of units, and even threaten the safe operation of units and even power stations in severe cases. In order to study the effect of the blade passage vortex and the vortex rope in the draft tube on the hydraulic losses under the part load conditions, the sliding mesh method and SST k-ω turbulence model are adopted. The blade passage vortex and the vortex rope in the draft tube captured by the latest Liutex vortex identification method undergo a contrastive analysis with the hydraulic loss of internal flow based on the entropy production theory. The results indicate that compared with the results in the references, the results of the research are verified accurate; under different upstream flow conditions, the proportion of the hydraulic losses of the spiral casing is small and has no obvious changes; the shock and stall phenomena, the dynamic-static interference, the relatively high flow velocity gradient, and the streamwise vortices in the guide vane domain are the main factors that cause the increase of entropy production; a large number of the blade passage vortices, the fluid-impact blades, and the tip leakage vortices are the main causing factors of the hydraulic losses in the runner; and the various shapes of the vortex rope in the draft tube can lead to the dramatic increase of the hydraulic losses of the draft tube as the opening decreases, and the hydraulic losses of the draft tube account for the largest proportion, followed by that of the runner. At the designed flow rate, the hydraulic loss of draft tube is 0.58 m, accounting for 50% of the total channel hydraulic loss, and that of runner is 0.38 m, accounting for 32.6% of the total channel hydraulic loss. When the flow rate drops to 55% of the designed flow rate, the hydraulic loss of draft tube is 1.95 m, accounting for 68% of the whole channel, and that of runner is 0.70 m, accounting for 24.4% of the whole channel. [ABSTRACT FROM AUTHOR]

An effective method for determination of multiple residues of phenoxy acid herbicides in cereals was developed. A QuEChERS (quick, easy, cheap, effective, rugged, and safe) technique coupled with high-performance liquid chromatography–tandem mass spectrometry (HPLC-MS/MS) was optimized for the analysis of phenoxy acid herbicides in rice, corn, and wheat. The limits of detection in the experiment were 0.0500 μg/kg for 4-(2,4-dichlorophenoxy)acetic acid, (4-chloro-2-methylphenoxy)acetic acid, (2,4,5-trichlorophenoxy)acetic acid, and 2-(2,4-dichlorophenoxy)propionic acid and 0.300 μg/kg for 4-(2,4-dichlorophenoxy)butyric acid and 3,6-dichloro-2-methoxybenzoic acid. The relative standard deviation of intraday and interday precision for the six phenoxy acid herbicides was less than 6.61%, and accuracy was 96.3 to 107%. Extraction recovery for phenoxy acid herbicides was 73.8 to 115%, with relative standard deviations of less than 12.1% at three spiking levels (1.00, 4.00, and 20.0 μg/kg). These results indicate that QuEChERS sample preparation with HPLC-MS/MS analysis is a rapid, reliable, highly sensitive, and specific tool for the determination of phenoxy acid herbicide residues in cereals. [ABSTRACT FROM AUTHOR]

Puerarin is an isoflavone derived from the Chinese medical herb of Radix puerariae (kudzu root), and has been widely used in the treatment for ischemic stroke in China. However, its underlying pharmacological mechanisms are still not understood. This study was to investigate the efficacy of puerarin on autophagy in the ischemic penumbra after cerebral stroke. A model of cerebral stroke in Sprague-Dawley rats was prepared by middle cerebral artery occlusion (MCAO); rats were then randomly divided into 5 groups: MCAO + Pue group (rats were treated with puerarin), MCAO + Pue + Tat-Beclin-1 group (rats were administrated with both puerarin and autophagy inducer Tat-Beclin-1), MCAO + Tat-Beclin-1 group (rats were treated with Tat-Beclin-1), MCAO + saline group (rats were administrated with the same volume of physiological saline), and sham surgery group. The autophagy levels in infarct penumbra were evaluated by western blotting, real-time PCR and immunofluorescence 14 days after the insult. Meanwhile, the neurological deficit score, brain water content and infarct volume were assessed. The results illustrated that the cerebral infarct volume, cerebral edema and neurological deficiency were significantly alleviated by puerarin treatment. Western blotting and the quantitative PCR revealed that the autophagy level in the penumbra was markedly reduced by puerarin administration. However, these effects of puerarin could be counteracted by Tat-Beclin-1. Additionally, double immunofluorescence showed that neuronal autophagy was markedly attenuated by puerarin treatment, whereas astrocytic autophagy was only mildly reduced. Our study suggests that puerarin could confer a neuroprotection against cerebral ischemia, and this biological function is associated with attenuating autophagy in neurons but not in astrocytes. [ABSTRACT FROM AUTHOR]

Background & Aims: Wnt signaling regulates hepatic function and nutrient homeostasis. However, little is known about the roles of β-catenin in cellular respiration or mitochondria of hepatocytes. Methods: We investigated β-catenin''s role in the metabolic function of hepatocytes under homeostatic conditions and in response to metabolic stress using mice with hepatocyte-specific deletion of β-catenin and their wild-type littermates, given either saline (sham) or ethanol (as a model of binge drinking and acute ethanol intoxication). Results: Under homeostatic conditions, β-catenin-deficient hepatocytes demonstrated mitochondrial dysfunctions that included impairments to the tricarboxylic acid cycle and oxidative phosphorylation (OXPHOS) and decreased production of adenosine triphosphate (ATP). There was no evidence for redox imbalance or oxidative cellular injury in the absence of metabolic stress. In mice with β-catenin-deficient hepatocytes, ethanol intoxication led to significant redox imbalance in the hepatocytes and further deterioration in mitochondrial function that included reduced OXPHOS, fatty acid oxidation (FAO), and ATP production. Ethanol feeding significantly increased liver steatosis and oxidative damage, compared with wild-type mice, and disrupted the ratio of nicotinamide adenine dinucleotide. β-catenin-deficient hepatocytes also had showed disrupted signaling of Sirt1/peroxisome proliferator-activated receptor-α signaling. Conclusions: β-catenin has an important role in the maintenance of mitochondrial homeostasis, regulating ATP production via the tricarboxylic acid cycle, OXPHOS, and fatty acid oxidation; β-catenin function in these systems is compromised under conditions of nutrient oxidative stress. Reagents that alter Wnt-β-catenin signaling might be developed as a useful new therapeutic strategy for treatment of liver disease. [Copyright &y& Elsevier]

Abstract: The evaluation of the effect of ecological restoration project is studied in this paper. Taking Qilihai wetland as a case, a comprehensive evaluation model based on System Dynamics (SD) is proposed. Firstly, the evaluation index system is established according to the actual situation of the wetland ecological restoration project, and the weight of each index can be calculated by Analytic Hierarchy Process (AHP). Then the simulation model based on SD is constructed, so the value of each evaluation index before and after the implementation of the project can be obtained. Finally, the comprehensive evaluation index before and after the project can be obtained with the weighted average method. The results show the model is effective and applicable. [Copyright &y& Elsevier]

Abstract: Purpose: Although a physiologic relationship between intestinal mucosal integrity and hepatic function has been previously described, the effect of primary liver disease on intestinal mucosal homeostasis has not been previously well documented. In the current study, we studied the effects of chronic liver injury as a primary injury on enterocyte turnover (proliferation and apoptosis) in a mouse model. Methods: The liver toxin 3,5-diethoxycarbonyl-1,4-dihydrocollidine (DDC)-enriched diet was used to induce chronic cholestatic liver injury in mice. Livers and intestine were harvested after 3 weeks of dietary treatment of histologic analysis and a determination of cell proliferation (immunohistochemistry for Ki67), or apoptosis (immunohistochemistry for caspase-3), as well as a determination of Wnt/β-catenin signaling activity. Results: All DDC-fed animals exhibited histologic evidence of liver damage that was associated with the expansion of atypical ductal proliferation near the periportal areas and increased oxidative stress. In the intestine, DDC-induced liver damage was associated with decreased villus height, decreased enterocyte proliferation, and increased cell apoptosis compared with control animals. There was also evidence for decreased β-catenin expression by immunostaining in crypt and villus cells of DDC-fed mice compared with control animals. Conclusion: Primary liver injury and cholestasis is associated with intestinal mucosal hypoplasia. Decreased cell proliferation and increased cell apoptosis may be responsible for decreased intestinal epithelial cell mass. The observed decrease in cell turnover is accompanied by an alteration in Wnt/β-catenin signaling. [Copyright &y& Elsevier]

Background & Aims: Keratins 8 and 18 (K8/K18) are important hepatoprotective proteins. Animals expressing K8/K18 mutants show a marked susceptibility to acute/subacute liver injury. K8/K18 variants predispose to human end-stage liver disease and associate with fibrosis progression during chronic hepatitis C infection. We sought direct evidence for a keratin mutation–related predisposition to liver fibrosis using transgenic mouse models because the relationship between keratin mutations and cirrhosis is based primarily on human association studies. Methods: Mouse hepatofibrosis was induced by carbon tetrachloride (CCl4) or thioacetamide. Nontransgenic mice, or mice that over express either human Arg89-to-Cys (R89C mice) or wild-type K18 (WT mice) were used. The extent of fibrosis was evaluated by quantitative real-time reverse-transcription polymerase chain reaction of fibrosis-related genes, liver hydroxyproline measurement, and Picro-Sirius red staining and collagen immunofluorescence staining. Results: Compared with control animals, CCl4 led to similar liver fibrosis but increased injury in K18 R89C mice. In contrast, thioacetamide caused more severe liver injury and fibrosis in K18 R89C as compared with WT and nontransgenic mice and resulted in increased messenger RNA levels of collagen, tissue inhibitor of metalloproteinase 1, matrix metalloproteinase 2, and matrix metalloproteinase 13. Analysis in nontransgenic mice showed that thioacetamide and CCl4 have dramatically different molecular expression responses involving cytoskeletal and chaperone proteins. Conclusions: Over expression of K18 R89C predisposes transgenic mice to thioacetamide- but not CCl4-induced liver fibrosis. Differences in the keratin mutation–associated fibrosis response among the 2 models raise the hypothesis that keratin variants may preferentially predispose to fibrosis in unique human liver diseases. Findings herein highlight distinct differences in the 2 widely used fibrosis models. [Copyright &y& Elsevier]

Background/Aims: Keratin-8 (KRT8)–null mice develop spontaneous colitis and predisposition to liver injury. Human studies show that some KRT8 variants predispose to end-stage liver disease and progression and suggest that such variants might associate with UC or CD. We asked whether mutations in KRT8 or KRT19, the major intestinal keratins, are associated with UC/CD. Methods: Exonic regions of the KRT8/KRT19 genes were polymerase chain reaction–amplified using genomic DNA from 2 independent groups. Group I included 91 unrelated patients with CD, 93 unrelated patients with UC, and 70 unrelated/unaffected volunteers. KRT8 variants were also tested with pyrosequencing in Group II that included 682 independent nuclear families with both parents and at least 1 CD/UC-affected offspring and 273 unaffected controls. Both cohorts were enriched for familial IBD. Results: In Group I, KRT19 variants were identified in CD/UC patients within the promoter and exons 1+2, with similar mutation frequencies in the control/CD/UC groups. In contrast, 16 of 184 CD+UC patients harbored KRT8 heterozygous variants involving Gly62-to-Cys and Arg341-to-His and a novel Arg341-to-Cys, which were noted in 4 volunteers (Arg341-to-His) and correlated with extensive UC (P = .005). One family with unaffected parents had 3 pediatric-affected siblings with severe disease, 2 of whom are compound heterozygous (Gly62-to-Cys/Arg341-to-His). However, there was no significant departure from random transmission of the 3 alleles in Group II IBD families. Conclusions: KRT8 and KRT19 variants are not overtransmitted or associated with familial IBD, although a potential role in sporadic IBD cannot be excluded. A novel but rare keratin-8 Arg341-to-Cys is identified in IBD patients. [Copyright &y& Elsevier]

Intermediate filament proteins (IFs) maintain cell and tissue integrity, based on evidence of their polymerization and mechanical properties, abundance and disease-associated phenotypes. This ‘traditional’ function is now augmented by organelle-related and protein-targeting roles. Mitochondrial location and function depend on intact IFs, as demonstrated for desmin, keratins and neurofilaments. Golgi positioning is regulated by several IFs, and endosomal/lysosomal protein distribution by vimentin. IFs dramatically affect nuclear function and shape and play a role in subcellular and membrane targeting of proteins. These functions have been noted in tissues but in some cases only in cell culture. The IF-related organelle-specific and protein-targeting roles, which are likely interrelated, provide functions beyond cell scaffolding and integrity and contribute to the cytoprotective and tissue-specific functions of IF proteins. [Copyright &y& Elsevier]

Background & Aims: Ischemia and reperfusion injury are common causes of oxidative tissue damage associated with many liver diseases and hepatic surgery. The Wnt–β-catenin signaling pathway is an important regulator of hepatic development, regeneration, and carcinogenesis. However, the role of Wnt signaling in the hepatocellular response to ischemia-reperfusion (I/R) injury has not been determined. Methods: Hepatic injury following ischemia or I/R was investigated in hepatocyte-specific, β-catenin–deficient mice, as well as Wnt1-overexpressing and wild-type (control) mice. Results: Wnt–β-catenin signaling was affected by the cellular redox balance in hepatocytes. Following ischemia or I/R, mice with β-catenin–deficient hepatocytes were significantly more susceptible to liver injury. Conversely, mice that overexpressed Wnt1 in hepatocytes were resistant to hepatic I/R injury. Hypoxia inducible factor (HIF)-1α signaling was reduced in β-catenin–deficient liver but increased in hepatocytes that overexpressed Wnt1 under hypoxia and following I/R, indicating an interaction between β-catenin and HIF-1α signaling in the liver. The mechanism by which Wnt signaling protects against liver injury involves the role of β-catenin as a transcriptional coactivator of HIF-1α signaling, which promotes hepatocyte survival under hypoxic conditions. Conclusions: Cellular redox balance affects Wnt–β-catenin signaling, which protects against hypoxia and I/R injury. These findings might be used to develop strategies for protection of hepatocytes, regeneration of liver, and inhibition of carcinogenesis. [ABSTRACT FROM AUTHOR]

Alcohol intake is associated with myocardial contractile dysfunction and apoptosis although the precise mechanism is unclear. This study was designed to examine the effect of the cytochrome P450 enzyme CYP2E1 inhibition on ethanol-induced cardiac dysfunction. Adult male mice were fed a 4% ethanol liquid or pair-fed control diet for 6weeks. Following 2weeks of diet feeding, a cohort of mice started to receive the CYP2E1 inhibitor diallyl sulfide (100 mg/kg/d, i.p.) for the remaining feeding duration. Cardiac function was assessed using echocardiographic and IonOptix systems. Western blot analysis was used to evaluate CYP2E1, heme oxygenase-1 (HO-1), iNOS, the intracellular Ca2+ regulatory proteins sarco(endo)plasmic reticulum Ca2+-ATPase, Na+ㅡCa2+ exchanger and phospholamban, pro-apoptotic protein cleaved caspase-3, Bax, c-Jun-NH2-terminal kinase (JNK) and apoptosis signal-regulating kinase (ASK-1). Ethanol led to elevated levels of CYP2E1, iNOS and phospholamban, decreased levels of HO-1 and Na+ㅡCa2+ exchanger, cardiac contractile and intracellular Ca2+ defects, cardiac fibrosis, overt O2− production, and apoptosis accompanied with increased phosphorylation of JNK and ASK-1, the effects were significantly attenuated or ablated by diallyl sulfide. Inhibitors of JNK and ASK-1 but not HO-1 inducer or iNOS inhibitor obliterated ethanol-induced cardiomyocyte contractile dysfunction, substantiating a role for JNK and ASK-1 signaling in ethanol-induced myocardial injury. Taken together, these findings suggest that ethanol metabolism through CYP2E1 may contribute to the pathogenesis of alcoholic cardiomyopathy including myocardial contractile dysfunction, oxidative stress and apoptosis, possibly through activation of JNK and ASK-1 signaling. [ABSTRACT FROM AUTHOR]

Abstract: Organic Rankine Cycle (ORC) is a promising technology for converting the low-grade energy to electricity. This paper presents an investigation on the parameter optimization and performance comparison of the fluids in subcritical ORC and transcritical power cycle in low-temperature (i.e. 80–100°C) binary geothermal power system. The optimization procedure was conducted with a simulation program written in Matlab using five indicators: thermal efficiency, exergy efficiency, recovery efficiency, heat exchanger area per unit power output (APR) and the levelized energy cost (LEC). With the given heat source and heat sink conditions, performances of the working fluids were evaluated and compared under their optimized internal operation parameters. The optimum cycle design and the corresponding operation parameters were provided simultaneously. The results indicate that the choice of working fluid varies the objective function and the value of the optimized operation parameters are not all the same for different indicators. R123 in subcritical ORC system yields the highest thermal efficiency and exergy efficiency of 11.1% and 54.1%, respectively. Although the thermal efficiency and exergy efficiency of R125 in transcritical cycle is 46.4% and 20% lower than that of R123 in subcritical ORC, it provides 20.7% larger recovery efficiency. And the LEC value is relatively low. Moreover, 22032L petroleum is saved and 74,019kg CO2 is reduced per year when the LEC value is used as the objective function. In conclusion, R125 in transcritical power cycle shows excellent economic and environmental performance and can maximize utilization of the geothermal. It is preferable for the low-temperature geothermal ORC system. R41 also exhibits favorable performance except for its flammability. [Copyright &y& Elsevier]