Introducing Highly Redox‐Active Atomic Centers into Insertion‐Type Electrodes for Lithium‐Ion Batteries

The development of alternative anode materials with higher volumetric and gravimetric capacity allowing for fast delithiation and, even more important, lithiation is crucial for next‐generation lithium‐ion batteries. Herein, the development of a completely new active material is reported, which follows an insertion‐type lithiation mechanism, metal‐doped CeO₂. Remarkably, the introduction of carefully selected dopants, herein exemplified for iron, results in an increase of the achievable capacity by more than 200%, originating from the reduction of the dopant to the metallic state and additional space for the lithium ion insertion due to a significant off‐centering of the dopant atoms in the crystal structure, away from the original Ce site. In addition to the outstanding performance of such materials in high‐power lithium‐ion full‐cells, the selective reduction of the iron dopant under preservation of the crystal structure of the host material is expected to open up a new field of research.     

The relative controls of temperature and soil moisture on the start of carbon flux phenology and net ecosystem production in two alpine meadows on the Qinghai-Tibetan Plateau

在温带和寒冷地区,春季植被物候的变化普遍受温度影响。然而,在寒冷地区的干旱/半干旱生态系统中,温度对物候的影响仍难以捉摸,因为土壤水分状况有调节物候的重要作用。利用生长度日(growing degree day, GDD)和生长季节指数(growing season index, GSI)模型,对最低温度(minimum daily temperature, T_min)与土壤水分(daily soil moisture, SM)进行耦合,探索热量需求和水文气候交互作用对青藏高原(QTP)两个不同降水状况的高寒草甸生态系统碳吸收期开始日期(start of carbon uptake period, SCUP)和净生态系统初级生产力(net ecosystem productivity, NEP)的影响。其中,一种是水分限制的高寒草原草甸生态系统,另一种是温度限制的高寒灌丛草甸生态系统。GDD模型和GSI模型与SCUP明显相关联：在湿润的高寒灌丛草甸生态系统中,SCUP对生长季前GDD和GSI的变化同样敏感;而在半干旱高寒草原草甸生态系统中,与GDD相比,SCUP对生长季前GSI的变化更敏感。这些不同模式表明,限制SCUP的气候因子由温度和水分有效性的平衡来决定。在湿润的高寒草甸生态系统中,在不受干旱胁迫的情况下,较高的SCUP温度敏感性可以最大化热效益,正如观察到的SCUPs与GDD模型模拟具有较高的线性相关系数(R²)和AIC。而在半干旱的草原化草甸中,较高的SCUP水分敏感性可以最大化水分效益,正如观测到的SCUPs与GSI模型模拟具有较高的R²和AIC。此外,虽然在高寒灌丛草甸生态系统中SCUPs由GDD决定,但两个高寒草甸生态系统NEP均受累积GSI控制。本研究重点强调湿润和半干旱高寒草甸生态系统水文气候交互作用对春季碳通量物候和植被生产力的影响;揭示半干旱地区高寒草甸生态系统物候和碳平衡模型中应该包括温度和水分条件。这些结果对改善植被物候模型具有重要意义,从而加深我们对将来植被物候、生产力和气候变化相互作用的理解。     

西藏大花红景天RcCATs与RcSODs基因克隆及功能分析

为探究过氧化氢酶(CAT)和超氧化物歧化酶(SOD)基因家族成员在西藏大花红景天高原恶劣生境适应性中的作用,利用生物信息学和qRT-PCR技术对其RcCATs和RcSODs基因家族成员的序列和表达模式进行了分析,并构建RcCAT和RcSOD1的pYES2.0表达载体与pGBKT7诱饵载体,分别进行了酵母胁迫分析和拟南芥酵母文库中互作蛋白的筛选。结果显示:(1)大花红景天中共有2条RcCAT基因,3条RcSOD基因和1条Cu/Zn SOD铜伴侣基因RcCCS。生物信息学分析显示上述基因的氨基酸序列与其同源基因具有较高的相似性(66.37%～94.51%),且均没有跨膜结构域,亚细胞位置预测RcCATs位于过氧化物酶体,RcSODs和RcCCS位于细胞质或线粒体。(2)qRT-PCR结果显示6个基因在根、茎、叶三个器官中均有表达且主要在叶片中表达,低温胁迫和植物激素ABA对基因表达量的影响显著。(3)酵母胁迫结果显示异源表达RcCAT和RcSOD1基因的阳性酵母菌株在冷、热、盐、碱、重金属和H₂O₂胁迫下的细胞活力均比pYES2.0空载菌株高。(4)通过酵母双杂交共筛选到4个与RcCAT互作明显的基因AtbHLH121(AT3G19860)、AtCPCK2(AT2G23070)、AtGRP4(AT5G50750)和AtRAPTOR1B(AT3G08850),3个与RcSOD1互作明显的基因AtEMB(AT5G11890)、AtMBP2(AT1G52030)和AtRH8(AT4G00660)。综上结果表明,大花红景天能够通过RcCATs和RcSODs基因广泛参与调控其生长发育、胁迫响应等代谢途径来适应高原恶劣的环境。     

Heterologous gene silencing induced by tobacco rattle virus (TRV) is efficient for pursuing functional genomics studies in woody plants

Virus-induced gene silencing (VIGS) is an effective tool for studying the functions of plant genes, but only a few VIGS vectors available for woody plants were reported so far. Here we present an effective heterologous VIGS system in woody plants based on tobacco rattle virus (TRV) vectors. We first tested whether the TRV-vector can be directly applied to infect woody plant species, such as Vernicia fordii, Populus tomentosa Carr. and Camellia oleifera. The results revealed that TRV-mediated VIGS could be effectively elicited in V. fordii, weakly in P. tomentosa Carr., but not in C. oleifera. TRV-based VIGS vectors with heterologous phytoene desaturase (PDS) sequences from various woody plant species silenced successfully the endogenous PDS gene in Nicotina benthamiana and V. fordii. The photobleached leaf phenotype of silenced plants significantly correlated with the down-regulation of endogenous PDS as compared with controls. To further confirm the reliability of VIGS in V. fordii, we also isolated the cloroplastos alterados 1 gene from P. tomentosa Carr., and the silencing pheotypes of albino leaves were observed in V. fordii 2 weeks after inoculation using a heterologous TRV-based VIGS system. Taken together, we have successfully developed an Agrobacterium-mediated VIGS assay in V. fordii and demonstrated that V. fordii as a heterologous VIGS system provides a valuable tool for functional genomic analysis in woody plant species.     

The Short-Term Effects of Exercise on Intraocular Pressure,Choroidal Thickness and Axial Length

Purpose

To explore ocular changes in healthy people after exercise.

Methods

Twenty five volunteers underwent exercise for 15 minutes on a treadmill. Measurements of choroidal thickness, intraocular pressure (IOP), ocular biometry, and blood pressure were taken before and after exercise. Enhanced Depth Imaging optical coherence tomography (EDI-OCT) was used to measure choroidal thickness at the fovea. Intraocular pressure (IOP) was measured by Goldmann applanation tonometry. Ocular biometric measures were collected using A scan ultrasound. Blood pressure was measured concurrently with the acquisition of the scans.

Results

Twenty five volunteers (25 eyes) with a mean age of 25.44±3.25 years were measured. There was a significant increase in systolic and diastolic pressure after exercise (P<0.05). The IOP showed a significant decrease after exercise (P<0.05). However there was no significant difference in the mean choroidal thickness, ocular axial length, anterior chamber depth, lens thickness, or vitreous length before and after exercise measurements (P>0.05).

Conclusion

There was a significant decrease in IOP from exercise without a change in choroidal thickness and ocular biometric measures. IOP and choroidal thickness were not correlated, suggesting that the IOP decrease from exercise is not due to changes in choridal thickness.     

Penicillin-binding proteins and cell wall composition in beta-lactam-sensitive and -resistant strains of Staphylococcus sciuri

A close homologue of the acquired Staphylococcus aureus mecA gene is present as a native gene in Staphylococcus sciuri. We determined the patterns of penicillin-binding proteins (PBPs) and the peptidoglycan compositions of several S. sciuri strains to explore the functions of this mecA homologue, named pbpD, in its native S. sciuri environment. The protein product of pbpD was identified as PBP4 with a molecular mass of 84 kDa, one of the six PBPs present in representatives of each of three subspecies of S. sciuri examined. PBP4 had a low affinity for nafcillin, reacted with a monoclonal antibody raised against S. aureus PBP2A, and was greatly overproduced in oxacillin-resistant clinical isolate S. sciuri SS37 and to a lesser extent in resistant laboratory mutant K1M200. An additional PBP inducible by oxacillin and corresponding to S. aureus PBP2A was identified in another oxacillin-resistant clinical isolate, S. sciuri K3, which harbors an S. aureus copy of mecA. Oxacillin resistance depended on the overtranscribed S. sciuri pbpD gene in strains SS37 and K1M200, while the resistance of strain K3 depended on the S. aureus copy of mecA. Our data provide evidence that both S. aureus mecA and S. sciuri pbpD can function as resistance determinants in either an S. aureus or an S. sciuri background and that the protein products of these genes, S. aureus PBP2A and S. sciuri PBP4, can participate in the biosynthesis of peptidoglycan, the muropeptide composition of which depends on the bacterium “hosting” the resistance gene.