γδT细胞免疫疗法的最新临床研究进展

γδT细胞是固有免疫系统中的效应细胞,这些细胞以MHC不受限制的方式发挥作用,使它们成为癌症免疫治疗的理想介质,近年来在过继性T细胞免疫疗法中越来越受欢迎。T细胞有两种类型,包括αβT细胞和γδT细胞。前者表达T细胞受体(TCR),该受体包含α链和β链的异二聚体。后者表达包含γ链和δ链异二聚体的TCR,通常不表达共受体CD4和CD8,平均占人类外周血T细胞的4%。γδT细胞是MHC非依赖性的,并已被发现识别多种配体分子,如BTN家族蛋白(BTN2A1/BTN3A1和BTNL3/BTNL8)、MHC相关蛋白。γδT细胞通过其TCR识别这些分子,并表达先天受体,如NKG2D、Toll样受体(TLRs)和CD16。γδT细胞在对抗感染性和肿瘤疾病中发挥重要作用,γδT细胞的免疫反应本质上偏向于I型免疫,I型免疫对感染细胞和肿瘤细胞产生强烈的细胞毒性作用(主要通过颗粒酶B和穿孔素),并导致IFN-γ产生增加。已有的研究表明,γδT细胞与癌症的良好预后呈正相关。这进一步支持了在癌症治疗中引入γδT细胞免疫疗法。

短期氮处理(缺氧处理)对采后猕猴桃贮藏过程中抗氧化能力和质膜完整性的影响

将猕猴桃用氮气处理6 h后,在（1±1）℃、相对湿度为95%～100%条件下贮藏35 d,最后在20℃下放置3 d,测定果实硬度、质膜透性、硫代巴比妥酸反应产物（TBARS）、过氧化氢含量、超氧阴离子生成速率、脂氧合酶（LOX）、超氧化物歧化酶（SOD）和过氧化物酶（POD）的活性。

An Influence of the Noise on the Imaging Algorithm in the Electrical Impedance Tomography

Electrical impedance tomography (EIT) reconstructs the internal impedance distribution of the body from electrical measurements on body surface. The algorithm research is one of the main problems of the EIT. This paper presents the MPSO-MNR Algorithm, which is formed by combining the Modified Particle Swarm Optimization (MPSO) with Modified Newton-Raphson algorithm (MNR), gives the reconstruction results of certain configurations and analyzes the influence of the noise on the MPSO-MNR algorithm in the EIT. The numerical results show that the MPSO-MNR algorithm can reconstruct the resistivity distribution within the certain iterations. With the moving of the target to the centre of 2-D solution domain and the increase of noise, the border of the reconstruction objects becomes vague, and the fitness value and the total error increase gradually.

A novel TNKS/USP25 inhibitor blocks the Wnt pathway to overcome multi-drug resistance in TNKS-overexpressing colorectal cancer

Modulating Tankyrases(TNKS),interactions with USP25 to promote TNKS degradation,rather than inhibiting their enzymatic activities,is emerging as an alternative/specific approach to inhibit the Wnt/β-catenin pathway.Here,we identified UAT-B,a novel neoantimycin analog isolated from Streptomyces conglobatus,as a small-molecule inhibitor of TNKS-USP25 protein-protein interaction(PPI)to overcome multi-drug resistance in colorectal cancer(CRC).The disruption of TNKS-USP25 complex formation by UAT-B led to a significant decrease in TNKS levels,triggering cell apoptosis through modulation of the Wnt/β-catenin pathway.Importantly,UAT-B successfully inhibited the CRC cells growth that harbored high TNKS levels,as demonstrated in various in vitro and in vivo studies utilizing cell line-based and patient-derived xenografts,as well as APC^(min/+)spontaneous CRC models.Collectively,these findings suggest that targeting the TNKS-USP25 PPI using a small-molecule inhibitor represents a compelling therapeutic strategy for CRC treatment,and UAT-B emerges as a promising candidate for further preclinical and clinical investigations.

Synergistically assembled RGO/Si_(3)N_(4) whiskers hybrid aerogels to endow epoxy composites with excellent thermal and tribological performance

Epoxy resin(EP)composites with satisfactory thermal and tribological performance are highly required for engineering moving components.However,the simple addition of fillers leaded to the serious filler agglomeration and limited promotion in tribological properties.In this work,we constructed a new kind of three-dimensional(3D)reduced graphene oxide(RGO)/Si_(3)N_(4) hybrid aerogel for EP composites,which was prepared by a facile hydrothermal self-assembly method followed by freeze-drying technique.As a result,the dispersibility of Si_(3)N_(4) whiskers was greatly improved through wrapping of polydopamine–polyethyleneimine copolymer(PDA–PEI)copolymer and physical spacing of 3D skeleton.Furthermore,benefiting from the synergistic effect of RGO and Si_(3)N_(4)@PDA–PEI in the thermal network,the thermal conductivity of RGO/Si_(3)N_(4) hybrid aerogel(GSiA)–EP increased by 45.4%compared to that of the neat EP.In addition,the friction coefficient and wear rate of GSiA–EP decreased by 83.7%and 35.8%,respectively.This work is significant for opening a tribological performance enhancement strategy though constructing 3D hybrid architecture.

Event-based Two-stage Non-intrusive Load Monitoring Method Involving Multi-dimensional Features

This paper proposes an event-based two-stage Nonintrusive load monitoring(NILM)method involving multidimensional features,which is an essential technology for energy savings and management.First,capture appliance events using a goodness of fit test and then pair the on-off events.Then the multi-dimensional features are extracted to establish a feature library.In the first stage identification,several groups of events for the appliance have been divided,according to three features,including phase,steady active power and power peak.In the second stage identification,a“one against the rest”support vector machine(SVM)model for each group is established to precisely identify the appliances.The proposed method is verified by using a public available dataset;the results show that the proposed method contains high generalization ability,less computation,and less training samples.

Biosynthesis of trialkyl-substituted aromatic polyketide NFAT-133 involves unusual P450 monooxygenase-mediating aromatization and a putative metallo-beta-lactamase fold hydrolase

The bacterial trialkyl-substituted aromatic polyketides are structurally featured with the unusual aromatic core in the middle of polyketide chain such as TM-123(1),veramycin A(2),NFAT-133(3)and benwamycin I(4),which were discovered from Streptomyces species and demonstrated with antidiabetic and immunosuppressant activities.Though the biosynthetic pathway of 1-3 was reported as a type I polyketide synthase(PKS),the PKS assembly line was interpreted inconsistently,and it remains a mystery how the compound 3 was generated.Herein,the PKS assembly logic of 1-4 was revised by site-mutagenetic analysis of the PKS dehydratase domains.Based on gene deletion and complementation,the putative P450 monooxygenase nftE1 and metallo-beta-lactamase(MBL)fold hydrolase nftF1 were verified as essential genes for the biosynthesis of 1-4.The absence of nftE1 led to abolishment of 1-4 and accumulation of new products(5-8).Structural elucidation reveals 5-8 as the non-aromatic analogs of 1,suggesting the NftE1-catalyzed aromatic core formation.Deletion of nftF1 resulted in disappearance of 3 and 4 with the compounds 1 and 2 unaffected.As a rare MBL-fold hydrolase from type I PKSs,NftF1 potentially generates the compound 3 through two strategies:catalyze premature chain-offloading as a trans-acting thioesterase or hydrolyze the lactone-bond of compound 1 as an esterase.

非核糖体多肽Surugamides生物合成基因簇镶嵌式结构的解析

【目的】多肽化合物Surugamides(sgm)生物合成基因簇包含4个非核糖体多肽合酶(NRPS)基因surA–D,负责2个NRPS生物合成途径。已有报道确认surA基因与SurugamideA产物相关,而surB基因与sgm F产物相关,但对surC和surD基因功能的归属尚没有实验证据。本工作拟在之前研究的基础上进一步确认surA和surD负责Surugamide A产物生物合成,为基因工程改造Surugamides生物合成途径以及研究其NRPS蛋白之间的识别机制提供理论依据。【方法】从海绵中分离放线菌并通过16S rRNA基因序列比对分析其分类单元。通过在线数据库antiSMASH分析基因组序列,发现天然产物生物合成基因簇。通过UPLC-Q-TOF-MS和^(13)CNMR鉴定化合物结构。把构建完成的同源重组双交换质粒导入链霉菌宿主后筛选基因缺失或替换突变株。【结果】从胄甲海绵来源链霉菌S.albidoflavus LHW3101基因组中发现了Surugamides生物合成基因簇,确认了该菌株发酵产物中的化合物sgmA和sgm F。构建了surB和surC基因同时缺失的突变株RJ9,发现RJ9不再产sgm F而仍然产Surugamide A。在缺失突变surB和surC基因的同时在surD基因前引入了组成型强启动子ermEp*,结果发现RJ9产SurugamideA水平是野生型菌株的约2倍。【结论】确认了surB和surC基因与sgmA产物无关。在surD基因前引入强启动子后显著提高了SurugamideA的产量,提示surD基因与sgmA产物相关,结合已报到surA基因与Surugamide A产物相关的证据,进一步确认了surA和surD基因负责Surugamide A生物合成的推论。

Antimicrobial Chlorinated Carbazole Alkaloids from the Sponge-Associated Actinomycete Streptomyces diacarni LHW51701

Four new chlorinated carbazole alkaloids,chlocarbazomycins(CCBs)A-D,were isolated from sponge associated bacterium Streptomyces diacarni LHW51701.Their structures were elucidated via spectroscopic techniques(including HRESIMS,ID&2D NMR),and X-ray crystallographic analysis.Structurally,the 4-chloro coupled with 3-methoxyl substituents in the tricycle nucleus of CCBs A-D and the A/-methoxyl group of CCB-D are rare in naturally occurred tricyclic carbazole alkaloids.Moreover,CCBs A-D do not bear the typical Cl poro-alkyl and C2 meto-methyl side chains of bacterial tricycle carbazoles,suggesting a novel mechanism of aromatic ring formation in biosynthesis.The biological evaluation showed that CCB-C possessed inhibitory activities against pathogenic microorganisms including methicillin-resistant Staphylococcus aureus(MRSA),Mycobacterium smegmatis,Bacillus mycoides,and Candida albicans.

Investigation of carbonyl amidation and O-methylation during biosynthesis of the pharmacophore pyridyl of antitumor piericidins

Piericidins are a large family of bacterialα-pyridone antibiotics with antitumor activities such as their anti-renal carcinoma activity exhibited recently in nude mice.The backbones of piericidins are derived fromβ,δ-diketo carboxylic acids,which are offloaded from a modular polyketide synthase(PKS)and putatively undergo a carbonyl amidation beforeα-pyridone ring formation.The tailoring modifications to theα-pyridone structure mainly include the verified hydroxylation and O-methylation of the C-4′position and an unidentified C-5′O-methylation.Here,we describe a piericidin producer,terrestrial Streptomyces conglobatus,which contains a piericidin biosynthetic gene cluster in two different loci.Deletion of the amidotransferase gene pieD resulted in the accumulation of two fatty acids that should be degraded from the nascent carboxylic acid released by the PKS,supporting the carbonyl amidation function of PieD duringα-pyridone ring formation.Deletion of the O-methyltransferase gene pieB1 led to the production of three piericidin analogues lacking C-5′O-methylation,therefore confirming that PieB1 specifically catalyses the tailoring modification.Moreover,bioactivity analysis of the mutant-derived products provided clues regarding the structure-function relationship for antitumor activity.The work addresses two previously unidentified steps involved in pyridyl pharmacophore formation during piericidin biosynthesis,facilitating the rational bioengineering of the biosynthetic pathway towards valuable antitumor agents.

Genomic scanning enabling discovery of a new antibacterial bicyclic carbamate-containing alkaloid

Non-ribosomal peptides are a group of structurally diverse natural products with various important therapeutic and agrochemical applications.Bacterial pyrrolizidine alkaloids(PAs),containing a scaffold of two fused five-membered ring system with a nitrogen atom at the bridgehead,have been found to originate from a multidomain non-ribosomal peptide synthetase to generate indolizidine intermediates,followed by multistep oxidation,catalysed by single Bayer-Villiger(BV)enzymes,to yield PA scaffolds.Although bacterial PAs are rare in natural product inventory,bioinformatics analysis suggested that the biosynthetic gene clusters(BGCs)that are likely to be responsible for the production of PA-like metabolites are widely distributed in bacterial genomes.However,most of the strains containing PA-like BGCs are not deposited in the public domain,therefore preventing further assessment of the chemical spaces of this group of bioactive metabolites.Here,we report a genomic scanning strategy to assess the potential of PA metabolites production in our culture collection without prior knowledge of genome information.Among the strains tested,we found fifteen contain the key BV enzymes that are likely to be involved in the last step of PA ring formation.Subsequently one-strain-many-compound(OSMAC)method,supported by a combination of HR-MS,NMR,SMART 2.0 technology,and GNPS analysis,allowed identification and characterization of a new[5+7]heterobicyclic carbamate,legoncarbamate,together with five known PAs,bohemamine derivatives,from Streptomyces sp.CT37,a Ghanaian soil isolate.The absolute stereochemistry of legoncarbamate was determined by comparison of measured and calculated ECD spectra.Legoncarbamate displays antibacterial activity against E.coli ATCC 25922 with an MIC value of 3.1μg/mL.Finally,a biosynthetic model of legoncarbamate and other bohemamines was proposed based on the knowledge we have gained so far.