Celastrol prevents cadmium‐induced neuronal cell death via targeting JNK and PTEN‐Akt/mTOR network

Cadmium (Cd), a toxic environmental contaminant, induces neurodegenerative diseases. Celastrol, a plant‐derived triterpene, has shown neuroprotective effects in various disease models. However, little is known regarding the effect of celastrol on Cd‐induced neurotoxicity. Here, we show that celastrol protected against Cd‐induced apoptotic cell death in neuronal cells. This is supported by the findings that celastrol strikingly attenuated Cd‐induced viability reduction, morphological change, nuclear fragmentation, and condensation, as well as activation of caspase‐3 in neuronal cells. Concurrently, celastrol remarkably blocked Cd‐induced phosphorylation of c‐Jun N‐terminal kinase (JNK), but not extracellular signal‐regulated kinases 1/2 and p38, in neuronal cells. Inhibition of JNK by SP600125 or over‐expression of dominant negative c‐Jun potentiated celastrol protection against Cd‐induced cell death. Furthermore, pre‐treatment with celastrol prevented Cd down‐regulation of phosphatase and tensin homolog deleted on chromosome 10 (PTEN) and activation of phosphoinositide 3′‐kinase/protein kinase B (Akt)/mammalian target of rapamycin (mTOR) signaling in neuronal cells. Over‐expression of wild‐type PTEN enhanced celastrol inhibition of Cd‐activated Akt/mTOR signaling and cell death in neuronal cells. The findings indicate that celastrol prevents Cd‐induced neuronal cell death via targeting JNK and PTEN‐Akt/mTOR network. Our results strongly suggest that celastrol may be exploited for the prevention of Cd‐induced neurodegenerative disorders.

     

Alleviation of the detrimental effect of water deficit on wheat (Triticum aestivum L.) growth by an indole acetic acid-producing endophytic fungus

Plant and Soil - Endophytic fungi colonization is an eco-friendly strategy to respond to environmental stresses and confer tolerance to the host plant. Here, the responses of wheat plant inoculated...     

Ruthenium Triazine Composite: A Good Match for Increasing Hydrogen Evolution Activity through Contact Electrification

The development of Pt‐free catalysts for the alkaline hydrogen evolution reaction (HER), which is widely used in industrial scale water‐alkali electrolyzers, remains a contemporary and pressing challenge. Ruthenium (Ru) has excellent water‐dissociation abilities and could be an alternative water splitting catalyst. However, its large hydrogen binding energy limits HER activity. Here, a new approach is proposed to boost the HER activity of Ru through uniform loading of Ru nanoparticles on triazine‐ring (C₃N₃)‐doped carbon (triNC). The composite (Ru/triNC) exhibits outstanding HER activity with an ultralow overpotential of ≈2 mV at 10 mA cm^?2; thereby making it the best performing electrocatalyst hitherto reported for alkaline HER. The calculated metal mass activity of Ru/triNC is >10 and 15 times higher than that of Pt/C and Pt/triNC. Both theoretical and experimental studies reveal that the triazine‐ring is a good match for Ru to weaken the hydrogen binding on Ru through interfacial charge transfer via increased contact electrification. Therefore, Ru/triNC can provide the optimal hydrogen adsorption free energy (approaching zero), while maintaining the strong water‐dissociation activity. This study provides a new avenue for designing highly efficient and stable electrocatalysts for water splitting.     

Mutant plant viruses with cell binding motifs provide differential adhesion strengths and morphologies

The ability of Tobacco mosaic virus (TMV) to tolerate various amino acid insertions near its carboxy terminus is well-known. Typically these inserts are based on antigenic sequences for vaccine development with plant viruses as carriers. However, we determined that the structural symmetries and the size range of the viruses could also be modeled to mimic the extracellular matrix proteins by inserting cell-binding sequences to the virus coat protein. The extracellular matrix proteins play important roles in guiding cell adhesion, migration, proliferation, and stem cell differentiation. Previous studies with TMV demonstrated that the native and phosphate-modified virus particles enhanced stem cell differentiation toward bone-like tissues. Based on these studies, we sought to design and screen multiple genetically modified TMV mutants with reported cell adhesion sequences to expand the virus-based tools for cell studies. Here, we report the design of these mutants with cell binding amino acid motifs derived from several proteins, the stabilities of the mutants against proteases during purification and storage, and a simple and rapid functional assay to quantitatively determine adhesion strengths by centrifugal adhesion assay. Among the mutants, we found that cells on TMV expressing RGD motifs formed filopodial extensions with weaker attachment profiles, whereas the cells on TMV expressing collagen I mimetic sequence displayed little spreading but higher attachment strengths.     

脓毒症急性肾损伤患者血液净化时机选择对治疗期间微循环系统的影响研究

目的:探究脓毒症急性肾损伤患者血液净化时机选择对治疗期间微循环系统的影响。方法:选取2016年2月～2017年2月期间来我院治疗的脓毒症急性肾损伤患者200例作为研究对象,依据急性肾损伤的诊断和分级(RIFLE)标准将脓毒症急性肾损伤患者分为1期(A组,n=56)、2期(B组,n=70)、3期(C组,n=74),所有患者皆采取连续性肾脏替代疗法。观察不同时期治疗前后微循环的变化。结果:三组脓毒症急性肾损伤患者在性别、年龄、空腹血糖浓度、急性生理功能和慢性健康状况(APACHE)评分、体温、心率指标上差异无统计学意义(P0.05);治疗后,A组患者微血管流动指数低于B组和C组,而灌注血管比例、灌注血管密度及总血管密度显著高于B组和C组(P0.05);A组患者血液流态积分、襻周状态积分、管襻形态积分及总积分显著低于B组和C组(P0.05),而襻顶血管直径显著大于B组和C组(P0.05)。结论:在RLFLE诊断标准1期对脓毒症急性肾损伤患者实施血液净化,可以明显地改善治疗效果,促进微循环系统的恢复。     

采用稳定碳同位素法分析白羊草在不同干旱胁迫下的水分利用效率

本研究以黄土高原乡土草种白羊草(Bothriochloa ischaemum(L.)Keng.)为研究对象,采用盆栽控制实验,比较白羊草在3个水分处理(CK80%FC、MS60%FC和SS 40%FC)下的生物量积累和分配模式、瞬时水分利用效率(WUE)、不同部位(新叶、老叶、茎、细根、粗根)的稳定碳同位素组成(δ~(13)C)和碳同位素分辨率(Δ~(13)C)及其相互关系,以及干旱胁迫下影响水分利用效率的主导环境因子。结果表明:1)重度干旱胁迫显著降低植物整体生物量,显著增加根冠比和细根生物量比例;2)随着干旱胁迫加剧,白羊草各器官的δ~(13)C均呈上升趋势,Δ~(13)C呈减小趋势,SS处理不同器官δ~(13)C和Δ~(13)C没有显著差异,CK和MS处理的各器官δ~(13)C均值表现分别为细根粗根老叶新叶茎、细根新叶老叶粗根茎,CK和MS处理Δ~(13)C的值总体呈根叶茎。3)新叶的δ~(13)CNL和Δ~(13)CNL与WUE的相关系数均最大,说明利用稳定碳同位素方法测定白羊草水分利用效率具有可行性。4)不同水分处理的WUE的主导影响因子不同,CK、MS、SS水分处理WUE分别受到叶面温度、大气水汽压亏缺和空气温度的影响最大。为采用稳定碳同位素方法指示白羊草水分利用效率可行性及阐明植物的胁迫响应机制提供理论依据。     

锁定接骨板治疗肱骨近端骨折

目的:探讨锁定钢板治疗肱骨近端骨折的临床疗效。方法:2005年3月～2010年3月应用锁定钢板(包括肱骨近端锁定钢板或肱骨近端锁定内固定系统)治疗肱骨近端骨折43例,按Neer分型2部分骨折20例,3部分骨折19例,4部分骨折4例。随访评定包括X线片、Neer肩关节功能评分标准。结果:43例患者获得平均14.2个月(9～21个月)临床随访,骨折全部愈合,愈合平均时间10.4周(8～12周)。根据Neer肩关节功能评分标准:优19例,良19例,可5例,优良率88.4%。结论:锁定钢板治疗肱骨近端骨折具有手术创伤小、操作方便、固定可靠的优点,允许早期功能锻炼,疗效满意。     

双钩巢粉虱产卵分泌物的化学成分

双钩巢粉虱Paraleyrodes pseudonaranjae Martin原产于南美洲,现已分布于美国的佛罗里达、夏威夷和中国的香港、广东、广西、海南等地.这种粉虱的产卵方式与螺旋粉虱Aleurodicus disperses Russell等相似,卵粒以白色的分泌物覆盖.本文采用气相色谱/质谱联用技术研究了双钩巢...