Protein Phosphatase 2A Catalytic Subunit α Plays a MyD88-Dependent,Central Role in the Gene-Specific Regulation of Endotoxin Tolerance

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Highlights? PP2Ac is constitutively activated and targets MyD88 in LPS-tolerized macrophages ? Constitutively active PP2Ac shifts a proinflammatory MyD88 to its prosurvival mode ? Constitutively active PP2Ac reprograms gene-specific chromatin modification landscape ? Constitutively active PP2Ac broadly defines ET at both signaling and epigenetic levels     

Combining Nature‐Inspired,Graphene‐Wrapped Flexible Electrodes with Nanocomposite Polymer Electrolyte for Asymmetric Capacitive Energy Storage

Two kinds of free‐standing electrodes, reduced graphene oxide (rGO)‐wrapped Fe‐doped MnO₂ composite (G‐MFO) and rGO‐wrapped hierarchical porous carbon microspheres composite (G‐HPC) are fabricated using a frozen lake‐inspired, bubble‐assistance method. This configuration fully enables utilization of the synergistic effects from both components, endowing the materials to be excellent electrodes for flexible and lightweight electrochemical capacitors. Moreover, a nonaqueous HPC‐doped gel polymer electrolyte (GPE‐HPC) is employed to broad voltage window and improve heat resistance. A fabricated asymmetric supercapacitor based on G‐MFO cathode and G‐HPC anode with GPE‐HPC electrolyte achieves superior flexibility and reliability, enhanced energy/power density, and outstanding cycling stability. The ability to power light‐emitting diodes also indicates the feasibility for practical use. Therefore, it is believed that this novel design may hold great promise for future flexible electronic devices.     

Effect of Mn toxicity on morphological and physiological changes in two <Emphasis Type="Italic">Populus cathayana</Emphasis> populations originating from different habitats

The cuttings of Populus cathayana were exposed to four different manganese (Mn) concentrations (0, 0.1, 0.5 and 1 mM) in a greenhouse to investigate the toxicity of Mn and the detoxifying responses of woody plants. Two contrasting populations of P. cathayana, which were from wet and dry climate regions in western China, respectively, were examined in our study. The results showed that high concentration of Mn caused significant decrease in shoot height, biomass accumulation, and leaf number and leaf areas. Injuries to the anatomical features of leaves were also found as the reduced thickness of palisade and spongy parenchyma, the decreased density in the conducting tissue and the collapse and split in the meristematic tissue in the central vein. Moreover, Mn treatments caused the accumulation of hydrogen peroxide (H₂O₂), and then resulted in oxidative stress indicated by the oxidation of proteins and DNA. Many physiological responses were employed to cope with the toxicity of Mn, including the increase in the contents of non-protein thiol (NP-SH), phytochelatins (PCs) and phenolics compounds and the stimulated activities of guaiacol peroxidase (GPX) and polyphenol oxidase (PPO) for the chelation of Mn and for the antioxidation of reactive oxygen species. The population from dry climate habitat showed a lower leaf concentration of Mn, higher contents of the chelators, and higher activities of GPX and PPO than did the wet climate population at the same Mn treatment, thereby possessing a superior Mn tolerance. In both populations, most of the Mn was accumulated in the shoot, which is favorable regarding phytoremediation.     

Internalization of CD40 regulates its signal transduction in vascular endothelial cells

The CD40 ligand (CD40L)-CD40 dyad can ignite proinflammatory and procoagulatory activities of the vascular endothelium in the pathogenesis and progression of atherosclerosis. Besides being expressed on the activated CD4(+) T cell surface (mCD40L), the majority of circulating CD40L reservoir (sCD40L) in plasma is released from stimulated platelets. It remains debatable which form of CD40L triggers endothelial inflammation. Here, we demonstrate that the agonistic antibody of CD40 (G28.5), which mimics the action of sCD40L, induces rapid endocytosis of CD40 independent of TRAF2/3/6 binding while CD40L expressed on the surface of HEK293A cells captures CD40 at the cell conjunction. Forced internalization of CD40 by constitutively active mutant of Rab5 preemptively activates NF-kappaB pathway, suggesting that CD40 was able to form an intracellular signal complex in the early endosomes. Internalized CD40 exhibits different patterns of TRAF2/3/6 recruitment and Akt phosphorylation from the membrane anchored CD40 complex. Finally, mCD40L but not sCD40L induces the upregulation of proinflammatory cytokines and cell adhesion factors in the primary human vascular endothelial cells in vitro, although both forms of CD40L activate NF-kappaB pathway. These results therefore may help understand the molecular mechanism of CD40L signaling that contributes to the pathophysiology of atherosclerosis.     

Contrasting responses in the growth and energy utilization properties of sympatric Populus and Salix to different altitudes: implications for sexual dimorphism in Salicaceae

An interesting ecological and evolutionary puzzle arises from the observations of male‐biased sex ratios in genus Populus, whereas in the taxonomically related Salix, females are generally more dominant. In the present study, we combined results from a field investigation into the sex ratios of the Salicaceous species along an altitudinal gradient on Gongga Mountain, and a pot experiment by monitoring growth and energy utilization properties to elucidate the mechanisms governing sexual dimorphism. At middle altitudes 2000 and 2300 m, the sex ratios were consistent with a 1:1 equilibrium in sympatric Populus purdomii and Salix magnifica. However, at the lower and higher ends of the altitudinal gradient, skewed sex ratios were observed. For example, the male:female ratios were 1.33 and 2.36 in P. purdomii at 1700 and 2600 m respectively; for S. magnifica the ratio was 0.62 at 2600 m. At 2300 m, the pot‐grown seedlings of both species exhibited the highest biomass accumulation and total leaf area, simultaneously with the balanced sex ratios in the field. At 3300 m, the specific leaf area in male P. purdomii was 23.9% higher than that of females, which may be the morphological cause for the observed 19.3% higher nitrogen allocation to Rubisco, and 20.6% lower allocation to cell walls. As such, male P. purdomii showed a 32.9% higher foliar photosynthetic capacity, concomitant with a 12.0% lower construction cost. These properties resulted in higher photosynthetic nitrogen‐ and energy‐use efficiencies, and shorter payback time (24.4 vs 40.1 days), the time span that a leaf must photosynthesize to amortize the carbon investment. Our results thus suggested that male P. purdomii evolved a quicker energy‐return strategy. Consequently, these superior energy gain‐cost related traits and the higher total leaf area contributed to the higher growth rate and tolerance in stress‐prone environments, which might, in part, shed new light on the male‐biased sex ratios in Populus. However, no significant sexual difference was observed in S. magnifica for all the above parameters, thereby implying that the female‐biased sex ratios in Salix cannot be explained in terms of the energy‐use properties studied here.     

模拟根系分泌物输入对高寒退化草地土壤微生物残体的影响

微生物残体是稳定土壤碳库的重要来源,对退化生境碳的固持和积累具有重要意义。植物根系分泌物作为植物-土壤-微生物"交流"的媒介,是调控土壤微生物残体迁移转化的关键。因此,以极度退化草地土壤为对象,以氨基糖为标志物,模拟研究了不同氮浓度（低氮-LN：0.1 gN/kg;高氮-HN：0.2 gN/kg）和多样性（3种化合物、9种化合物）根系分泌物输入对土壤微生物残体的影响。结果表明：（1）根系分泌物输入可显著增加高寒退化草地土壤微生物残体含量,且主要由真菌残体贡献。其中高氮和低多样性处理增加最明显,微生物残体和真菌残体分别增加了101.14%,125.16%,而低氮和高多样性处理微生物残体和真菌残体仅增加了35.79%,33.51%。（2）根系分泌物的输入可增加土壤β-葡萄糖苷酶、土壤磷酸酶和过氧化物酶活性,促进微生物的生长,而降低β-N-乙酰氨基葡萄糖苷酶活性,减少微生物残体的分解。（3）回归分析结果显示,土壤微生物残体与土壤环境的C/N呈显著负相关,与微生物生物量C/N呈显著正相关。上述结果表明,在未来退化草地恢复中,可充分利用模拟根系分泌物输入的土壤固碳策略,即通过提高土壤氮的有效性,促进微生物的生长,加快代谢周转,进一步提高微生物残体含量。     

R753Q Polymorphism Inhibits Toll-like Receptor (TLR) 2 Tyrosine Phosphorylation,Dimerization with TLR6, and Recruitment of Myeloid Differentiation Primary Response Protein 88

The R753Q polymorphism in the Toll-IL-1 receptor domain of Toll-like receptor 2 (TLR2) has been linked to increased incidence of tuberculosis and other infectious diseases, but the mechanisms by which it affects TLR2 functions are unclear. Here, we studied the impact of the R753Q polymorphism on TLR2 expression, hetero-dimerization with TLR6, tyrosine phosphorylation, and recruitment of myeloid differentiation primary response protein (MyD) 88 and MyD88 adapter-like (Mal). Complementation of HEK293 cells with transfected WT or R753Q TLR2 revealed their comparable total levels and only minimal changes in cell surface expression of the mutant species. Notably, even a 100-fold increase in amounts of transfected R753Q TLR2 versus WT variant did not overcome the compromised ability of the mutant TLR2 to activate nuclear factor κB (NF-κB), indicating that a minimal decrease in cell surface levels of the R753Q TLR2 cannot account for the signaling deficiency. Molecular modeling studies suggested that the R753Q mutation changes the electrostatic potential of the DD loop and results in a discrete movement of the residues critical for protein-protein interactions. Confirming these predictions, biochemical assays demonstrated that R753Q TLR2 exhibits deficient agonist-induced tyrosine phosphorylation, hetero-dimerization with TLR6, and recruitment of Mal and MyD88. These proximal signaling deficiencies correlated with impaired capacities of the R753Q TLR2 to mediate p38 phosphorylation, NF-κB activation, and induction of IL-8 mRNA in transfected HEK293 cells challenged with inactivated Mycobacterium tuberculosis or mycobacterial components. Thus, the R753Q polymorphism renders TLR2 signaling-incompetent by impairing its tyrosine phosphorylation, dimerization with TLR6, and recruitment of Mal and MyD88.