Low sperm motility is one of the main causes of male infertility. Cystic fibrosis transmembrane conductance regulator (CFTR, an anion channel protein) is related to the progressive motility of sperm. CFTR disruptor CFTRinh-172 or forskolin (FSK) in this study were used to treat human sperm separately, and the rates of sperm autophagy and progressive motility, mitochondrial membrane potential (MMP) and ATP concentration, and the expression levels of related factors were detected to explore their relationship. It was showed that sperms treated with CFTRinh-172 or FSK reduced the levels of cAMP, CFTR and PKA, but increased sperm autophagy rate, expression levels of AMPK and LC3B. However, reactive oxygen species content had no significant difference. It was indicated that low level of CFTR performed with cAMP and its downstream effectors such as PKA and AMPK to regulate mitochondrial structure and function, leading to increased autophagy rate and reduced vitality of sperm.
Jie HuHan LiuChaoyan OuLiangzhao LiuLinfeng MoXuming LiangYonghua He
Tetracycline repressor(TetR)family regulators(TFRs)are the largest group of DNA-binding transcription factors and are widely distributed in bacteria and archaea.TFRs play vital roles in controlling the expression of various genes and regulating diverse physiological processes.Recently,a TFR protein Pseudomonas virulence regulator A(PvrA),was identified from Pseudomonas aeruginosa as the transcriptional activator of genes involved in fatty acid utilization and bacterial virulence.Here,we show that PvrA can simultaneously bind to multiple pseudo-palindromic sites and upregulate the expression levels of target genes.Cryo-electron microscopy(cryo-EM)analysis indicates the simultaneous DNA recognition mechanism of PvrA and suggests that the bound DNA fragments consist of a distorted B-DNA double helix.The crystal structure and functional analysis of PvrA reveal a hinge region that secures the correct domain motion for recognition of the promiscuous promoter.Additionally,our results showed that mutations disrupting the regulatory hinge region have differential effects on biofilm formation and pyocyanin biosynthesis,resulting in attenuated bacterial virulence.Collectively,these findings will improve the understanding of the relationship between the structure and function of the TetR family and provide new insights into the mechanism of regulation of P.aeruginosa virulence.
The ethanol oxidation reaction(EOR)is crucial in direct alcohol fuel cells and chemical production.However,the electro-oxidation of ethanol molecules to produce acetaldehyde and carbon monoxide can poison the active sites of nanocatalysts,resulting in reduced performance and posing challenges in achieving high activity and selectivity for ethanol oxidation.In this study,we employed a dynamic seed-mediated method to precisely modify highly dispersed Ru sites onto well-defined Pd nanocrystals.The oxyphilic Ru sites serve as"OH valves",regulating water dissociation,while the surrounding Pd atomic arrangements control electronic states for the oxidation dehydrogenation of carbonaceous intermediates.Specifically,Ru0.040@Pd nanocubes(Ru:Pd=0.04 at.%),featuring(100)facets in Ru-Pd4 configurations,demonstrate an outstanding mass activity of 6.53 A·mgPd^(-1) in EOR under alkaline conditions,which is 6.05 times higher than that of the commercial Pd/C catalyst(1.08 A·mgPd-1).Through in-situ experiments and theoretical investigations,we elucidate that the hydrophilic Ru atoms significantly promote the dynamic evolution of H_(2)O dissociation into OHads species,while the electron redistribution from Ru to adjacent Pd concurrently adjusts the selective oxidation of C_(2) intermediates.This host-guest interaction accelerates the subsequent oxidation of carbonaceous intermediates(CH_(3)CO_(ads))to acetate,while preventing the formation of toxic*CHx and*CO species,which constitutes the rate-determining step.
Zhihe XiaoYueguang ChenRenjie WuYuwei HeChunfeng ShiLeyu Wang
The mixing effectiveness of the airflow between the inner and outer bypass inlets of a Rear Variable-Area Bypass Injector(RVABI)is the key to the afterburner performance of variable cycle engines.This paper describes an optimized RVABI design based on an alternating area regulator to improve the velocity/temperature uniformity of the incoming flow at the afterburner.Compared with a classical RVABI,numerical simulations show that the proposed alternating RVABI performs better in terms of thermal mixing efficiency and total pressure loss in different variable cycle engine modes.Both the increasing air contact area between the inner and outer bypass of alternating structure RVABI,and a larger streamwise vortex in the inner bypass inlet due to the proposed alternating lobe structure in the RVABI contribute to the significantly increase of mixing effectiveness.Besides,the alternating regulator induces strong streamwise vortex,which helps to improve the airflow mixing with its vortex-induced velocity.The interaction between the streamwise vortex and azimuthal vortex further promises the velocity/temperature uniformity after the RVABI.With the increase of alternating lobe’s height ratio,the covering area of the streamwise vortex and the azimuthal vortex is enlarged,which further enhances the thermal mixing efficiency of the RVABI.This design gives an insight into the future design and optimization of RVABI.
Runfu LIUZhenyao LIHuiliu ZHANGQixing WANGYue HUANGYancheng YOU