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The evaluation of college physical education (PE) teaching quality is an indispensable part of the teaching process. Building a scientific, comprehensive, reasonable and effective evaluation system is crucial to improving the quality of college PE classroom teaching. This process is not easy, and requires long-term efforts and persistence. The PE teaching quality evaluation in Colleges and Universities is frequently viewed as the multiple attribute decision making (MADM) issue. In such paper, Taxonomy method is designed for MADM under double-valued neutrosophic sets (DVNSs). First, the score function of DVNSs and Criteria Importance Through Intercriteria Correlation (CRITIC) method is used to derive the attribute weights. Second, then, the optimal choice is obtained through calculating the smallest double-valued neutrosophic number (DVNN) development attribute values from the DVNN positive ideal solution (DVNNPIS). Finally, a numerical example for PE teaching quality evaluation is given to illustrate the built method.

With the advancement of technology, new problems and challenges also follow, among which the more serious problem is media forgery. Forged media information brings a lot of inconvenience to life. It is difficult to distinguish the truth from the false. In this article, various types of forgery are listed and elaborated with a focus on the copy-move forgery category, the study and research involving copy-move forgery(CMF) detection techniques using the Local Binary Pattern (LBP) are presented. The technical review of recent state-of-the-art LBP-based is provided.

Under physiological conditions, Bacillus fastidious uricase (BFU) activity shows negligible lagging phase before the exponential decrease; mutants are thus designed for long lagging phases before exponential activity decreases. On homodimer surface of BFU (4R8X.pdb), the last fragment ANSEYVAL at the C-terminus forms a loop whose Y319 is H-bonded by the buried D257 in the same monomer. Within 1.5 nm from the α-carboxyl group of the last leucine (L322), E30, K26, D257, R258, E311, K312 and E318 from the same monomer plus D126 and K127 from a monomer of the other homodimer generate an electrostatic interaction network. Within 1.5 nm from Y319, D307 and R310 in the same monomer interact with ionized residues around the inter-chain β-sheet in the same homodimer. Mutagenesis of Y319R is designed to strengthen the original interactions and concomitantly generate new electrostatic attractions between homodimers. Under physiological conditions, the mutant V144A/Y319R showed an approximately 4 week lagging phase before the exponential activity decrease, an apparent half-life of activity nearly three folds of mutant V144A, but comparable activity. The introduction of ionizable residues into the C-terminus contacting the other homodimer for additional and/or stronger electrostatic attractions between homodimers may be a universal approach to thermostable mutants of uricases.

The gut-microbiota-brain axis is the most important complex and bidirectional pathway between the gastrointestinal tract and the central nervous system. This study investigated the potential of microbe-induced gut-to-brain signaling to modulate the effect of stress on depressive-like behavior, intestinal barrier, and neuroinflammation. Result showed that fecal microbiota transplantation increased the consumption of sucrose solutions and decreased the immobility time in forced swimming test. This treatment also increased Firmicutes and decreased Bacteroidetes and Desulfobacterota at phylum levels; reduced the loss of villi and epithelial cells; suppressed the inflammatory cell infiltration in the ileum; increased the expression of ZO-1, occludin; protected the mucosal layer function; and suppressed the high levels of inflammasomes (NLRP3, ASC, caspase-1, and IL-1β) in rat brain. In summary, fecal microbiota transplantation improves the depressive-like behavior, alters the gut microbiota imbalance, and alleviates the intestinal tract inflammation, intestinal mucosa disruption, and neuroinflammation in rats induced by chronic unpredictable mild stress.

Multifunctional oxide thin films exhibit a broad palette of properties, such as ferroelectricity, piezoelectricity, dielectricity, superconductivity, and metal-insulator transition (MIT); therefore...

Background Hepatitis B virus (HBV) causes acute and chronic infection in the clinic. Hepatocellular carcinoma (HCC) is closely linked to HBV infection. Serum Golgi protein 73 (GP73) increases during HBV infection. However, the role of GP73 during HBV infection and the occurrence of HBV-related HCC is still poorly understood. Methods The underlying role of HBV-induced GP73 in regulating HCC development was investigated in this study. GP73 expression in HBV-related clinical HCC tissues and in HBV-infected hepatoma cells and primary human hepatocytes was evaluated by immunohistochemistry, ELISAs, Western blotting and quantitative real-time PCR (qRT-PCR) analysis. Tumorigenicity of GP73 overexpressed cells was detected by flow cytometry, qRT-PCR, xenograft nude mouse analyses and sphere formation assays. The effects of GP73 and HBV infection on host innate immune responses in hepatocytes were further investigated by Western blotting and qRT-PCR analysis. Results Initially, we confirmed that HBV-positive HCC tissues had significantly higher expression of GP73. Ectopic expression of the HBV gene could induce GP73 expression in primary human hepatocytes and hepatoma cells in vitro. In addition, we discovered that GP73 promotes HCC in both normal liver cells and hepatoma cells. We also found that ectopic expression of HBV genes increases GP73 expression, suppressing the host's innate immune responses in hepatocytes. Conclusions Our results demonstrate that HBV facilitates HCC development by activating GP73 to repress the host's innate immune response. This study adds to our understanding of the pathogenesis of HBV infection-induced HCC. The findings also provide preclinical support for GP73 as a potential HCC prevention or treatment target.

Emerging evidence suggests that the microbiota-gut-brain axis affects a variety of complex behaviors, including social, emotional, and depressive-like behaviors. Peyer's patches (PPs), a well-characterized gut-associated lymphoid tissue, are the entry site for luminal antigens and the initiation site for antigen-specific immune responses. However, few studies have explored the composition of lymphoid tissue-resident commensal bacteria (LRCs) in stress-associated disorders. Male C57BL/6 mice exposed to chronic social stress were analyzed for microbiome on the interior of PPs and changes in inflammation. Susceptible mice (SUS) exhibited a composition of bacteria inside PPs that was distinct from that of control (CON) and resilient (RES) mice, including an increase in Candidatus Arthromitus (SFB) and a decrease in Lactobacillus. The CD4+ CD25+ Foxp3+ T cells were significantly reduced in SUS mice. Relative mRNA levels of IL-2 were significantly reduced in SUS mice, and the mRNA levels of Bcl-6, IFN-γ, IL-6, and the IgA protein levels in the ileum were significantly increased. Moreover, in the prefrontal cortex of SUS mice, IL-6 and TNF-α were increased, whereas IL-10 was decreased. The correlational analyses revealed that social interaction ratio was negatively correlated with SFB and positively associated with Lactobacillus and four other candidate protective organisms. These results pointed the possibility that the changes in the LRCs induced by chronic social defeat stress were ultimately associated with the inflammation of the brain and exacerbation of depressive-like behaviors.

Nanoscale phase mixtures in transition-metal oxides (TMOs) often render these materials susceptible to external stimuli (electric field, mechanical stress, etc.), which can lead to rich functional properties and device applications. Here, direct observation and multifield manipulation of a nanoscale mixture of brownmillerite SrFeO

The outbreak of COVID-19, caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections, spread across hosts from humans to animals, transmitting particularly effectively in mink. How SARS-CoV-2 selects and evolves in the host, and the differences in the evolution of different animals are still unclear. To analysis the mutation and codon usage bias of SARS-CoV-2 in infected humans and animals. The SARS-CoV-2 sequence in mink (Mink-SARS2) and binding energy with receptor were calculated compared with human. The relative synonymous codon usage of viral encoded gene was analyzed to characterize the differences and the evolutionary characteristics. A synonymous codon usage analysis showed that SARS-CoV-2 is optimized to adapt in the animals in which it is currently reported, and all of the animals showed decreased adaptability relative to that of humans, except for mink. The neutrality plot showed that the effect of natural selection on different SARS-CoV-2 sequences is stronger than mutation pressure. A binding affinity analysis indicated that the spike protein of the SARS-CoV-2 variant in mink showed a greater preference for binding with the mink receptor ACE2 than with the human receptor, especially as the mutation Y453F and N501T in Mink-SARS2 lead to improvement of binding affinity for mink receptor. In summary, mutations Y453F and N501T in Mink-SARS2 lead to improvement of binding affinity with mink receptor, indicating possible natural selection and current host adaptation. Monitoring the variation and codon bias of SARS-CoV-2 provides a theoretical basis for tracing the epidemic, evolution and cross-species spread of SARS-CoV-2.

SARS-CoV-2 infection, which is the cause of the COVID-19 pandemic, has expanded across various animal hosts, and the virus can be transmitted particularly efficiently in minks. It is still not clear how SARS-CoV-2 is selected and evolves in its hosts, or how mutations affect viral fitness. In this report, sequences of SARS-CoV-2 isolated from human and animal hosts were analyzed, and the binding energy and capacity of the spike protein to bind human ACE2 and the mink receptor were compared. Codon adaptation index (CAI) analysis indicated the optimization of viral codons in some animals such as bats and minks, and a neutrality plot demonstrated that natural selection had a greater influence on some SARS-CoV-2 sequences than mutational pressure. Molecular dynamics simulation results showed that the mutations Y453F and N501T in mink SARS-CoV-2 could enhance the binding of the viral spike to the mink receptor, indicating the involvement of these mutations in natural selection and viral fitness. Receptor binding analysis revealed that the mink SARS-CoV-2 spike interacted more strongly with the mink receptor than the human receptor. Tracking the variations and codon bias of SARS-CoV-2 is helpful for understanding the fitness of the virus in virus transmission, pathogenesis, and immune evasion.

Strain engineering has been widely applied to tune the performance of oxide thin film based devices. To precisely regulate the strain state of the thin film, nevertheless, still remains a challenging task. Herein, we demonstrate that the uniaxial strain along the c-axis of epitaxial SrCoO2.5 (SCO) (001) thin film can be continuously controlled by low-energy helium (He) irradiation (5 keV), leading to noticeable enhancement in resistive switching (RS) performance. All the irradiated SCO thin films exhibit out-of-plane tensile strain due to the implanted He interstitials in the lattice, and the strain increases linearly from 0.447% to 2.785% as the ion fluence increases from 1 × 1014 to 1 × 1015 ion/cm2. Although all the irradiated SCO-based devices follow similar conductive filaments mechanism as the pristine device, the performance shows a volcano shape dependence on the irradiation fluence. The device subjected to irradiation of 1 × 1014 ion/cm2 shows the optimal performance with the highest ON/OFF ratio and good endurance. Such dependence of RS behavior on irradiation-induced uniaxial strain is attributed to the widely observed nonlinear dependence of oxygen migration on the elastic tensile strain. Our results provide an effective strategy to regulate the strain states and the correlating functionality of oxide thin films.

Data in this article are associated with the research article "Ampholytic ion-exchange materials coated with small zwitterion for high-efficacy purification of ionizable soluble biomacromolecules" (Rao et al., 2018) [1]. This article provided data on how to design ampholytic ion-exchange material (AIEM) for the purification of ionizable soluble biomacromolecules for both high activity yields and favorable homogeneity, with two uricases as protein models and a plasmid as DNA model. Data were made publicly available for further analyses.

For the purification of soluble proteins and nucleic acids through ion-exchange, the ampholytic ion-exchange materials (AIEMs) were designed, which possessed both short aliphatic carboxyl and short aliphatic amines/imidazole at optimized ratios on solid supports coated with high density of small zwitterions; under optimized conditions, the soluble ionizable biomacromolecules were adsorbed on those AIEMs via electrostatic attractions and eluted effectively through electrostatic repulsions. As the proof-of-concept, magnetic submicron particles bearing short aliphatic carboxyl and the coats of small zwitterion served as the starting solid supports, which were conjugated with lysine alone, or with lysine plus glycine or N,N‑dimethylethylenediamine, to yield magnetic AIEMs whose surfaces possessed zero net charges at different pH. Such magnetic AIEMs exhibited ideal efficacy to release acid red 13 as an anion at the elution pH optimized for strong electrostatic repulsions; those magnetic AIEMs were proven absorbing under optimized conditions for the purification of soluble proteins stable at pH close to their isoelectric points and solid-phase extraction of nucleic acids in applicable biological mixtures. Therefore, the designed AIEMs are promising for the high-efficacy purification of ionizable soluble biomacromolecules.

Under physiological conditions, Bacillus fastidious uricase (BFU) activity shows negligible lagging phase before the exponential decrease; mutants are thus designed for long lagging phases before exponential activity decreases. On homodimer surface of BFU (4R8X.pdb), the last fragment ANSEYVAL at the C-terminus forms a loop whose Y319 is H-bonded by the buried D257 in the same monomer. Within 1.5 nm from the α-carboxyl group of the last leucine (L322), E30, K26, D257, R258, E311, K312 and E318 from the same monomer plus D126 and K127 from a monomer of the other homodimer generate an electrostatic interaction network. Within 1.5 nm from Y319, D307 and R310 in the same monomer interact with ionized residues around the inter-chain β-sheet in the same homodimer. Mutagenesis of Y319R is designed to strengthen the original interactions and concomitantly generate new electrostatic attractions between homodimers. Under physiological conditions, the mutant V144A/Y319R showed an approximately 4 week lagging phase before the exponential activity decrease, an apparent half-life of activity nearly three folds of mutant V144A, but comparable activity. The introduction of ionizable residues into the C-terminus contacting the other homodimer for additional and/or stronger electrostatic attractions between homodimers may be a universal approach to thermostable mutants of uricases.

Summary Ferroelectric synapses using polarization switching (a purely electronic switching process) to induce analog conductance change have attracted considerable interest. Here, we propose ferroelectric photovoltaic (FePV) synapses that use polarization-controlled photocurrent as the readout and thus have no limitations on the forms and thicknesses of the constituent ferroelectric and electrode materials. This not only makes FePV synapses easy to fabricate but also reduces the depolarization effect and hence enhances the polarization controllability. As a proof-of-concept implementation, a Pt/Pb(Zr0.2Ti0.8)O3/LaNiO3 FePV synapse is facilely grown on a silicon substrate, which demonstrates continuous photovoltaic response modulation with good controllability (small nonlinearity and write noise) enabled by gradual polarization switching. Using photovoltaic response as synaptic weight, this device exhibits versatile synaptic functions including long-term potentiation/depression and spike-timing-dependent plasticity. A simulated FePV synapse-based neural network achieves high accuracies (>93%) for image recognition. This study paves a new way toward highly controllable and silicon-compatible synapses for neuromorphic computing., Graphical Abstract, Highlights • Switchable ferroelectric photovoltaic (FePV) effect is used for synaptic application • Tunable photovoltaic response is enabled by gradual polarization switching • Versatile synaptic functions and high image recognition accuracy are achieved • The FePV synapses are facilely grown on silicon substrates, Circuit Systems; Electrical Engineering; Semiconductor Manufacturing; Materials Science; Devices

Background Evidence from previous studies has demonstrated that the gut-microbiota-brain axis is vital in regulating of behavior and neuroinflammation in the central nervous system. Considering the putative connection among gut microbiota, neural function, and behavior, the present study investigated the potential signaling of gut microbiota to modulate depression-like behaviors and neuroinflammation. Methods Rats showing depression-like behaviors induced by chronic unpredictable mild stress received fecal microbiota treatment or vehicle for 14 days, and alterations in behavior and neuroinflammation were assessed. ELISA, immunofluorescence staining and Western blot were used to analysis the activation of glial cells and NLRP3 inflammasome. Results Treatment with fecal microbiota transplantation ameliorated depression-like behaviors. 5-Hydroxytryptamine decreased in the chronic unpredictable mild stress rat model but significantly increased after fecal microbiota transplantation. The treatment with fecal microbiota transplantation decreased the production of IL-1β and TNF-α. Moreover, fecal microbiota transplantation administration suppressed the activation of Iba1 positive microglia cells and GFAP positive astrocytes cells and reduced the expression of NLRP3, ASC, Caspase-1, and IL-1β pathway in the prefrontal cortex and hippocampus. Conclusions Fecal microbiota transplantation can improve depression-like behaviors induced by chronic unpredictable mild stress. The anti-depression effects of fecal microbiota transplantation were associated with the suppressed activation of glial cells and NLRP3 inflammasome in the brain.

Background Alterations in bidirectional gut–brain interactions are believed to be involved in the pathogenesis of neuropsychiatric diseases. Considering the putative connections among gut microbiota, neural function, and behavior, this study investigated the potential of microbe-induced gut–to–brain signaling to modulate the impact of stress on depressive-like behaviors and serotonin metabolism. Methods Depression-susceptible mice induced by chronic social defeat stress received oral treatment of either Lactobacillus reuteri 3 (L. reuteri 3) or vehicle for 28 days, and alterations in behavior and serotonin metabolism were assessed. 16S rRNA sequencing and gas chromatograph were employed to analyze the gut microbiota community and short-chain fatty acids (SCFAs). Results Treatment with L. reuteri 3 ameliorated depressive-like behaviors, suppressed the increase in the relative abundances of Clostridiales and Adlercreutzia, improved the decrease in abundances of Lactobacillus, Allobaculum, and Sutterella induced by stress, and significantly increased the proportion of Bifidobacterium. L. reuteri 3 reduced the acetate and total SCFAs levels in the depression group. Blood and colon 5-HT were decreased in depressive-like mice but were significantly ameliorated after L. reuteri 3 treatment. Moreover, L. reuteri 3 administration increased the expression of enzymes involved in serotonin biosynthesis but suppressed that of the enzymes involved in tryptophan metabolism along the kynurenine pathway in colon and prefrontal cortex. Conclusions Despite the complexity of the gut microbiota, exposure to a single microbial strain L. reuteri 3 can protect against depressive-like behaviors induced by chronic social defeat stress. The anti-depressive effects of L. reuteri 3 were associated with improved gut microbiota and serotonin metabolism.

Distinct from the conductive filament-type counterparts, the interface-type resistive switching (RS) devices are electroforming-free and exhibit bidirectionally continuous conductance changes, making them promising candidates as analog synapses. While the interface-type RS devices typically operate through the interfacial oxygen migration, materials which can tolerate a wide range of oxygen non-stoichiometry and possess high oxygen mobility are therefore demanded. SrFeOx (SFO), which can easily transform between a conductive, oxygenated perovskite SrFeO3 (PV-SFO) phase and an insulating, oxygen-vacancy-rich brownmillerite SrFeO2.5 (BM-SFO) phase under electric field, emerges as a suitable material. Herein, an interface-type RS device is ingeniously structured by two epitaxial SFO layers: a PV-SFO matrix layer and an ultrathin BM-SFO interfacial layer, aiming to leverage the oxygen migration-induced interfacial BM-PV phase transformation to realize the gradual conductance modulation. Experimentally, the fabricated device exhibits electroforming-free, analog memristive behavior. This device also emulates essential synaptic functions, including excitatory postsynaptic current, paired-pulse facilitation, transition from short-term memory to long-term memory, spike-timing-dependent plasticity, and potentiation/depression. A simulated neural network built from the SFO-based synapses achieves accuracies above 88% for image recognition. This work provides a novel approach to use the SFO family of topotactic materials for developing analog synapses as building blocks for neuromorphic computing circuits.

As the fourth basic electronic component, the application fields of the memristive devices are diverse. The digital resistive switching with sudden resistance change is suitable for the applications of information storage, while the analog memristive devices with gradual resistance change are required in the neural system simulation. In this paper, a transparent device of ZnO films deposited by the magnetron sputtering on indium tin oxides (ITO) glass was firstly prepared and found to show typical analog memristive switching behaviors, including an I&ndash, V curve that exhibits a &lsquo, pinched hysteresis loops&rsquo, fingerprint. The conductive mechanism of the device was discussed, and the LTspice model was built to emulate the pinched hysteresis loops of the I&ndash, V curve. Based on the LTspice model and the Pavlov training circuit, a conditioned reflex experiment has been successfully completed both in the computer simulation and the physical analog circuits. The prepared device also displayed synapses-like characteristics, in which resistance decreased and gradually stabilized with time under the excitation of a series of voltage pulse signals.

Objective To develop an optimal inflammatory cell model from lipopolysaccharide (LPS)-stimulated phorbol ester (PMA)-differentiated THP-1 cells, and investigate its response to anti-inflammatory agent phosphodiesterase inhibitor rolipram. Methods THP-1 cells were differentiated by PMA and stimulated by LPS to release inflammatory factors in cell supernatants, like tumor necrosis factor α (TNF-α) and interleukin 6 (IL-6), which were detected by ELISA. The doses and durations of both PMA and LPS treatment were optimized to develop the inflammatory cell model. Rolipram was added along with LPS after PMA differentiation to assess the response of cells to the anti-inflammatory agent. Results THP-1 cells showed no significant differences in cell morphology between PMA treatment for 24 hours and for 48 hours, but significantly high levels of TNF-α and IL-6 were released under LPS treatment. TNF-α level increased significantly after the differentiation by PMA at 100 ng/mL in comparison with that at 50 ng/mL, and it increased in a LPS dose-depended manner untill a plateau at 0.2 μg/mL LPS; the secretion level of IL-6 increased remarkably when THP-1 cells were induced by PMA at 100 ng/mL and stimulated by LPS≥1 μg/mL. The inflammatory cell model made using PMA at 100 ng/mL and LPS at 0.5 μg/mL was more sensitive to the anti-inflammatory agent rolipram, compared with that by 0.1 μg/mL LPS. Conclusion PMA at 100 ng/mL was selected for the differentiation of THP-1 cells with the enhanced responsiveness to LPS stimulation; THP-1 cells by the induction of PMA at 100 ng/mL coupled with the stimulation of LPS at no less than 0.2 μg/mL was an optimal inflammatory cell model for significant secretion of TNF-α and IL-6, which was sensitive to the action of anti-inflammatory agents.

First-principles quantum mechanical/molecular mechanical (QM/MM)-free energy calculations have been performed to uncover how uricase catalyzes metabolic reactions of uric acid (UA), demonstrating that the entire reaction process of UA in uricase consists of two stages–oxidation followed by hydration. The oxidation consists of four steps: (1) chemical transformation from 8-hydroxyxythine to an anionic radical via a proton transfer along with an electron transfer, which is different from the previously proposed electron-transfer mechanism that involves a dianion intermediate (UA2−) during the catalytic reaction process; (2) proton transfer to the O2− anion (radical); (3) diradical recombination to form a peroxo intermediate; (4) dissociation of H2O2 to generate the dehydrourate. Hydration, for the most favorable pathway, is initiated by the nucleophilic attack of a water molecule on dehydrourate, along with a concerted proton transfer through residue Thr69 in the catalytic site. According to the calculated free energy profile, the hydration is the rate-determining step, and the corresponding free energy barrier of 16.2 kcal/mol is consistent with that derived from experimental kinetic data, suggesting that the computational insights into the catalytic mechanisms are reasonable. The mechanistic insights not only provide a mechanistic base for future rational design of uricase mutants with improved catalytic activity against uric acid as an improved enzyme therapy, but also are valuable for understanding a variety of other cofactor-free oxidase-catalyzed reactions involving an oxygen molecule.

Objective— Our laboratory has previously demonstrated that 15-lipoxygenase (15-LO)/15-hydroxyeicosatetraenoic acid (15-HETE) is involved in hypoxic pulmonary arterial hypertension. Chronic hypoxia–induced vascular inflammation has been considered as an important stage in the development of pulmonary arterial hypertension. Here, we determined the contribution of 15-HETE in the hypoxia–induced pulmonary vascular inflammation. Approach and Results— Chronic hypoxia–induced monocyte/macrophage infiltration and the expressions of intercellular adhesion molecule-1 and vascular cell adhesion molecule-1 were analyzed in hypoxic rat model and cultured pulmonary arterial endothelium cells using immunochemistry methods. We found that monocyte/macrophage infiltration and the expressions of intercellular adhesion molecules under hypoxia were markedly inhibited by 15-HETE inhibitors or 15-LO1/2 small interfering RNA. In addition, exogenous 15-HETE enhanced the expression of both adhesion molecules in pulmonary arterial endothelium cells in a time-dependent manner. Hypoxia–induced 15-LO1/2 expression in rat pulmonary arterial endothelium cells was significantly abolished by nuclear factor-κB inhibitors. Meanwhile, nuclear factor-κB activity was enhanced prominently by the 15-LO1/2 product, 15-HETE, suggesting a positive feedback mechanism. Conclusions— Taken together, our results suggest that chronic hypoxia promotes monocyte infiltration into the vasculature and adhesion molecules upregulation in pulmonary arterial endothelium cells via a positive interaction between 15-LO/15-HETE and nuclear factor-κB. Our study revealed a novel mechanism underlying hypoxia–induced pulmonary arterial inflammation and suggested new therapeutic strategies targeting 15-LO/15-HETE and nuclear factor-κB in the treatment of pulmonary arterial hypertension.

Prior to the exponential decrease of activity of a uricase from Candida sp. during storage at 37 °C, there was a plateau period of about 4 days at pH 7.4, 12 days at pH 9.2, and about 22 days in the presence of 30 μM oxonate at pH 7.4 or 9.2, but no degradation of polypeptides and no activity of resolved homodimers. To reveal determinants of the plateau period, a dissociation model involving a serial of conformation intermediates of homotetramer were proposed for kinetic analysis of the thermoinactivation process. In the dissociation model, the roles of interior noncovalent interactions essential for homotetramer integrity were reflected by an equivalent number of the artificial weakest noncovalent interaction; to avoid covariance among parameters, the rate constant for disrupting the artificial weakest noncovalent interaction was fixed at the minimum for physical significance of other parameters; among thermoinactivation curves simulated by numerical integration with different sets of parameters, the one for least-squares fitting to an experimental one gave the solution. Results found that the equivalent number of the artificial weakest noncovalent interaction primarily determined the plateau period; kinetics rather than thermodynamics for homotetramer dissociation determined the thermoinactivation process. These findings facilitated designing thermostable uricase mutants.

Peroxisome proliferator activated receptor gamma coactivator 1α (PGC-1α) induced by hypoxia regulates mitochondrial biogenesis and oxidative stress. However, the potential role of PGC-1α in hypoxia-promoted proliferation of pulmonary arterial vascular smooth muscle cells (PASMCs) is completely unknown. In this study, we found that hypoxia significantly induced the expression of PGC-1α in cultured PASMCs and activated mitochondrial biogenesis through upregulation of nuclear respiratory factor-1 and mitochondria transcription factor A in a time-dependent manner. Knockdown of PGC-1α by siRNA abrogated hypoxia-induced PASMCs proliferation via the downregulation of PCNA, cyclinA, and cyclinE. Furthermore, we observed that PI3K/Akt signaling pathway was involved in hypoxia induced PGC-1α expression and PASMCs proliferation. Taken together, these datas reveal PGC-1α as the key regulator to mediate mitochondrial biogenesis and the proliferation of PASMCs at an early stage of hypoxic exposure. This process might bring to light a potential adaptive mechanism for PASMCs to minimize hypoxic damage and our novel findings provide new insight into the development of hypoxic pulmonary hypertension.

Epoxyeicosatrienoic acids (EETs), cytochrome P450-derived metabolites of arachidonic acid, are endogenously produced epoxides that act as substrates for the soluble epoxide hydrolase (sEH). Recent studies indicate that EETs increase the tension of rat pulmonary arteries (PAs), and inhibition of sEH augments hypoxic pulmonary vasoconstriction. However, the mechanisms underlying the proconstrictive effects of sEH inhibitors in pulmonary artery smooth muscle cells (PASMCs) are unclear. In the present study, we used a sEH inhibitor, 12-(3-hexylureido) dodec-8-enoic acid (8-HUDE), to examine the ionic mechanisms underlying the constriction of PAs. 8-HUDE increased the tension of rat PAs to 145% baseline in a manner which was effectively eliminated by 10 μmol/L glibenclamide, an inhibitor of ATP-sensitive K(+) (K(ATP)) channels. Whole cell currents of HEK cells transfected with Kir6.1 or SUR2B were activated by K(ATP) channel opener pinacidil, inhibited by K(ATP) channel inhibitor glibenclamide or inhibited by 8-HUDE in a concentration-dependent manner with an IC50 value of 40 uM. In addition, 8-HUDE inhibited the expression of Kir6.1 and SUR2B at both mRNA and protein level in rat PASMCs. These observations suggest that 8-HUDE exerts acute effects on K(ATP) channel activity as well as subacute effects through decreased channel expression, and these effects are, at least in part, via the Kir6.1/SUR2B channel.

Epoxyeicosatrienoic acids (EETs), cytochrome P450-derived metabolites of arachidonic acid, have been reported to increase intracellular calcium concentration in aortic vascular smooth muscle cells (SMCs). As EETs are labile, we synthesized a new stable urea EET analog with agonist and soluble epoxide hydrolase (sEH) inhibitor properties. We refer to this analog, 12-(3-hexylureido)dodec-8-enoic acid, as 8-HUDE. Measuring tension of vascular rings, intracellular calcium signaling by confocal laser scanning microscopy and gene expression by reverse-transcription-PCR and western blots, we examined the effects of 8-HUDE on pulmonary vascular tone and calcium signaling in rat pulmonary artery (PA) SMCs (PASMCs). 8-HUDE increased the tension of rat PAs to 145% baseline, whereas it had no effect on the tension of mesenteric arteries (MAs). The 8-HUDE-induced increase in vascular tone was abolished by removal of extracellular Ca(2+) or by pretreatment with either La(3+) or SKF96365, which are inhibitors of canonical transient receptor potential channels (TRPCs). Furthermore, 8-HUDE-evoked increases in [Ca(2+)](i) in PASMCs could be blunted by inhibition of TRPC with SKF96365, removal of extracellular calcium or depletion of intracellular calcium stores with caffeine, cyclopiazonic acid or 2-aminoethoxydiphenyl borate, but not by the voltage-activated calcium channel blocker nifedipine. In addition to immediate effects on calcium signaling, 8-HUDE upregulated the expression of TRPC1 and TRPC6 at both mRNA and protein levels in rat PASMCs, whereas it suppressed the expression of sEH. Our observations suggest that 8-HUDE increases PA vascular tone through increased release of calcium from intracellular stores, enhanced [Ca(2+)](i) influx in PASMCs through store-operated Ca(2+) channels and modulated the expression of TRPC and sEH proteins in a proconstrictive manner.