T细胞的效应功能受有氧糖酵解的转录后调控

非增殖细胞将葡萄糖代谢为丙酮酸,进而进入线粒体的三羧酸循环,通过氧化磷酸化产生还原当量和ATP。然而,增殖细胞如激活的T细胞和癌细胞,它们进行糖酵解,在胞浆中将丙酮酸代谢为乳酸,有充足的氧气可以进行氧化磷酸化(OX-PHOS)。这一现象被称为Warburg效应。显然,后者在提供能量方面效率不如前者,提示这一过程可能有其他功能。之前有学者认为有氧糖酵解在增殖产生子细胞营养物质生物合成的过程中是必需的。但是氧化磷酸化转变为有氧糖酵解是T细胞激活而不是增殖的标志,所以作者希望探索有氧糖酵解对T细胞是否有增殖以外其他方面的功能。他们的研究成果发表在2013年6月6日在线出版的《细胞》(cell)杂志上。     

微RNA在肿瘤细胞糖代谢中的功能

大多数癌细胞产生能量是通过高速率糖酵解,然后在胞液中进行乳酸发酵。而在大多数正常细胞中,糖酵解速率相对较低,丙酮酸主要在线粒体中进行有氧氧化。即使在氧充足的条件下,快速生长的恶性肿瘤细胞进行糖酵解的速率通常要比其正常组织来源的细胞高二百多倍。微RNA（microRNA,miRNA）是一类具有转录后调控功能的非编码RNA。近年来,越来越多的研究表明,miRNA主要通过诱导缺氧环境、影响葡萄糖摄入、调节糖酵解过程中的关键酶以及乳酸去路等诸多方面参与糖代谢过程,从而在肿瘤细胞糖代谢中发挥重要作用。     

Glut1介导的葡萄糖摄取是B细胞急性淋巴细胞白血病合成代谢和抵抗凋亡所必需

<正>在有氧的条件下,许多肿瘤细胞都会利用有氧糖酵解来提供能量和支持细胞生长。这一细胞代谢的转变导致糖酵解的上调和乳酸产生的增加。在有氧糖酵解中探索出限制性的步骤,并通过代谢性手段来抑制肿瘤细胞反应,已经成为代谢性治疗肿瘤的关键问题。在临床中发现,大约1/4患有B细胞急性淋巴细胞白血病的病人中,B细胞中会出现致癌激酶BCR-Abl,这种病人一般预     

过表达2型丙酮酸激酶通过下调p53稳定性促进线粒体融合

正肿瘤细胞的代谢状态转变是有别于正常细胞的标志。大多数肿瘤细胞在有氧条件下仍表现出活跃的葡萄糖摄取及糖酵解,这种现象被称为Warburg效应。在这一过程中,丙酮酸激酶作为糖酵解的最后一步激酶,可以催化丙酮酸为乳酸并产生ATP。2型丙酮酸激酶(PKM2)高表达于胚胎组织及肿瘤细胞中。     

有氧糖酵解通过表观遗传机制促进Th1细胞分化

<正>有氧糖酵解是激活后T细胞的代谢特征,通常认为它通过3'非翻译区(3'UTR)调节机制而增强效应T细胞的免疫应答,例如调节促炎因子干扰素-γ(IFN-γ)的表达。在本文中,研究人员利用T细胞乳酸脱氢酶A(LDHA)特异性敲除小鼠,发现LDHA参与活化T细胞有氧糖酵解;LDHA敲除在不影响T细胞的生长、增殖、存活以及激活的情况下,可以促进IFN-γ的表达,但这个效应并不依赖于传统的3'UTR调节机制,同时也排除了在1型辅助T细胞(Th1)中T-bet的诱导的作用。     

基于有氧糖酵解的天然小分子抑制剂的研究进展CSCD

有氧糖酵解作为恶性肿瘤最显著的能量代谢特征之一,肿瘤细胞中大约有50%的ATP是通过有氧糖酵解途径合成的,同时糖酵解过程中产生的各种中间代谢产物也是合成蛋白质等生物大分子重要的原料来源。此外酵解途径导致的乳酸增加为肿瘤细胞提供了一个酸性成长环境,有利于其浸润和转移,因此其在维持肿瘤细胞能量需求、合成代谢平衡和肿瘤浸润和转移方面发挥着重要作用。研究表明有氧糖酵解的过程与葡萄糖转运蛋白、己糖激酶、丙酮酸激酶、磷酸果糖激酶等密切相关。目前靶向有氧糖酵解相关转运蛋白和关键限速酶已经成为抗肿瘤药物研发的有效途径,本文对目前天然产物中靶向有氧糖酵解相关蛋白的小分子抑制剂研究最新进展及作用机理进行总结,以期为相关领域药物研究人员提供新的思路和参考。     

瓦伯格效应促进生物合成的生化机制与模型

大部分肿瘤细胞在氧供充足时,仍会利用糖酵解来产生ATP,这种现象称为瓦伯格效应(Warburg effect)。这种产能效率远低于线粒体氧化磷酸化的代谢方式,其成因和对肿瘤发生发展的作用尚不明确。但科学界普遍认为肿瘤细胞一定从有氧糖酵解中获得生长优势。本文结合本实验室及学术界最新的研究结果,对瓦伯格效应促进生物合成的生化机制进行探讨,并在此基础上提出在葡萄糖充足或缺乏时肿瘤细胞均能维持生长优势的模型。     

何谓乳酸循环?

答:高等动物(包括人类),进行呼吸作用的主要方式是有氧呼吸,由糖类的分解为生命活动提供能量,是机体供能的主要代谢途径。但是,机体也普遍存在着无氧呼吸供能的代谢途径,即通过糖酵解为生命活动提供少量的能量,其最终产物是乳酸。激烈运动形成暂时缺氧状态或由于呼吸、循环机能障碍而供氧不足时,能供应大量能量的有氧氧化过程不能顺利进行。此时,糖酵解作用加强,以释放一部份能量应付急需,在这种情况下。糖酵解的最终产物乳酸产生过多,如不能及时转化,就会引起酸中毒现象。     

PKM2对乳腺癌细胞有氧糖酵解、增殖和凋亡的影响

[目的]探讨siRNA介导的PKM2基因沉默对乳腺癌细胞中有氧糖酵解、细胞增殖和凋亡产生的影响。[方法]荧光定量PCR检测乳腺癌细胞转染siRNA-PKM2的效率,葡萄糖和乳酸试剂盒及Western Blot检测细胞的糖酵解能力,CCK-8法检测细胞增殖能力,Western Blot检测细胞的凋亡状况。[结果]与对照组相比,转染PKM2的siRNA 48h后,细胞摄取葡萄糖量及乳酸分泌量均明显降低(P0.05),两种与糖酵解相关的蛋白Glut1和PFK-1表达量均降低;细胞增殖速率减慢(P0.05);抗凋亡蛋白bcl-x L蛋白表达降低,促凋亡蛋白caspase-9蛋白表达增多。[结论]siRNA介导的PKM2基因沉默能抑制乳腺癌细胞的有氧糖酵解及增殖能力,并促进细胞凋亡。     

无氧耐力运动状态下延缓机体血乳酸积累的训练方法探索

通过发展非原动肌群慢肌纤维有氧清除乳酸的能力,探索无氧耐力运动中,延缓血乳酸快速积累的训练方法.两组受试者在提高糖酵解能力的基础上,实验组增加小力量训练方法,发展非原动肌群的慢肌纤维,提高其清除血乳酸的能力.通过测试原动肌群丙酮酸激酶活性、非原动肌群苹果酸脱氢酶活性、400 m跑定量负荷后血乳酸浓度、400 m跑极量负荷后血乳酸清除速率等指标进行分析比较.结果表明:在发展原动肌群糖酵解能力的基础上,充分发展非原动肌群慢肌纤维有氧清除乳酸的能力,对于延缓运动中乳酸过快积累,是一种行之有效的训练方法.     

Curcuminoids as inhibitors of thioredoxin reductase: A receptor based pharmacophore study with distance mapping of the active site

Curcumin is the yellow pigment of turmeric that interacts irreversibly forming an adduct with thioredoxin reductase (TrxR), an enzyme responsible for redox control of cell and defence against oxidative stress. Docking at both the active sites of TrxR was performed to compare the potency of three naturally occurring curcuminoids, namely curcumin, demethoxy curcumin and bis-demethoxy curcumin. Results show that active sites of TrxR occur at the junction of E and F chains. Volume and area of both cavities is predicted. It has been concluded by distance mapping of the most active conformations that Se atom of catalytic residue SeCYS498, is at a distance of 3.56 from C13 of demethoxy curcumin at the E chain active site, whereas C13 carbon atom forms adduct with Se atom of SeCys 498. We report that at least one methoxy group in curcuminoids is necessary for interation with catalytic residues of thioredoxin. Pharmacophore of both active sites of the TrxR receptor for curcumin and demethoxy curcumin molecules has been drawn and proposed for design and synthesis of most probable potent antiproliferative synthetic drugs.     

A Unique Protease Cleavage Site Predicted in the Spike Protein of the Novel Pneumonia Coronavirus (2019-nCoV) Potentially Related to Viral Transmissibility

正Dear Editor,In December 2019, a novel human coronavirus caused an epidemic of severe pneumonia(Coronavirus Disease 2019,COVID-19) in Wuhan, Hubei, China(Wu et al. 2020; Zhu et al. 2020). So far, this virus has spread to all areas of China and even to other countries. The epidemic has caused 67,102 confirmed infections with 1526 fatal cases     

Comparative morphology of the carpel in the Liliaceae: Hewardieae, Petrosavieae, and Tricyrteae

The young pistils in the melanthioid tribes, Hewardieae, Petrosavieae and Tricyrteae, are uniformly tricarpellate and syncarpous. They lack raphide idioblasts. All are multiovulate, with bitegmic ovules. The Petrosavieae are marked by the presence of septal glands and incomplete syncarpy. Tepals and stamens adhere to the ovary in the Hewardieae and the Petrosavieae but not in the Tricyrteae. Two vascular bundles occur in the stamens of the Hewartlieae and Tricyrtis latifolia. Ventral bundles in the upper part of the ovary of the Hewardieae are continuous with compound septal bundles and placental bundles in the lower part. Putative ventral bundles occur in the alternate position in the Tricyrteae and putative placental bundles in the opposite. position in the Petrosavieae. The dichtomously branched stigma in each carpel of the Tricyrteae is supplied by a bifurcated dorsal bundle.     

Entwicklungsgeschichte und Ultrastruktur von Pollenkitt und Exine bei nahe verwandten entomophilen und anemophilen Angiospermensippen derAlismataceae,Liliaceae, Juncaceae,Cyperaceae, Poaceae undAraceae

Some closely related members of the monocotyledonous familiesAlismataceae, Liliaceae, Juncaceae, Cyperaceae, Poaceae andAraceae with variable modes of pollination (insect- and wind-pollination) were studied in relation to the ultrastructure of pollenkitt and exine (amount, consistency and distribution of pollenkitt on the surface of pollen grains). The character syndromes of pollen cementing in entomophilous, anemophilous and intermediate (ambophilous or amphiphilous) monocotyledons are the same in principal as in dicotyledons. Comparing present with former results one can summarize: 1) The pollenkitt is always produced in the same manner by the anther tapetum in all angiosperm sub-classes. 2) The variable stickiness of entomophilous and anemophilous pollen always depends on the particular distribution and consistency of the pollenkitt, but not its amount on the pollen surface. 3) The mostly dry and powdery pollen of anemophilous plants always contains a variable amount of inactive pollenkitt in its exine cavities. 4) A step-by step change of the pollen cementing syndrome can be observed from entomophily towards anemophily. 5) From the omnipresence of pollenkitt in all wind-pollinated angiosperms studied one can conclude that the ancestors of anemophilous angiosperms probably have been zoophilous (i.e. entomophilous) throughout.

     

Identification and Characterization of the First Equine Parainfluenza Virus 5

正Dear Editor,Parainfluenza virus 5 (PIV5), known as canine parainfluenza virus in the veterinary field, is a negative-sense,nonsegmented, single-stranded RNA virus belonging to the Paramyxoviridae family (Chen 2018). The virus was first reported in primary monkey kidney cells in 1954 (Hsiung1972), then it has been frequently discovered in various     

Pathogenic Characterization and Full Length Genome Sequence of a Reassortant Infectious Bursal Disease Virus Newly Isolated in Pakistan

<正>Dear Editor,Infectious bursal disease (IBD) is one of the most important diseases of the poultry. The IBD virus (IBDV), a nonenveloped virus belonging to the Birnaviridae family with a genome consisting of two segments of double-stranded RNA (segments A and B), targets B lymphocytes of bursa of Fabricious leading to immunosuppression. In Pakistan,poultry farming is the second biggest industry and IBD is the second biggest disease threating the poultry sector.However, there is limited genome information of IBDV