“微生物-肠-脑”轴介导的宿主食欲调节

人和动物的食欲受到中枢神经系统和外周激素的协同调控。近年来，一些研究指出肠道菌群的组成与变化通过多重途径影响宿主的食欲。肠道细菌分泌和产生的大量功能性代谢物如短链脂肪酸、次级胆汁酸和氨基酸衍生物等是其发挥调控作用的重要媒介物质。此外，肠道菌群还能够影响消化系统营养感知、肠迷走神经信号投递、肠道激素分泌等，这些也都会参与食欲和进食调节。在明确细菌调控食欲的作用机制后靶向调控和重组肠道微生物可能是改善宿主食欲的一种新策略，有助于厌食症、暴食症等相关疾病的诊治。     

肠道微生物对疾病发生发展和中药代谢的影响

人类肠道中寄生着数以万亿计的以细菌为主的微生物,它们组成了一个庞大的生物反应器,由饮食营养推动进而产生大量的生物活性物质。肠道微生物及其代谢产物通过多种途径作用于其他器官,使得肠道微生物与宿主的大脑、肝脏、肺脏、新陈代谢、免疫系统、激素系统等联系起来。微生物-宿主的交流对维持人体健康至关重要。最近研究发现肠道菌群与神经退行性疾病、炎症性疾病、肥胖、行为异常及神经发育等有关。同时,肠道微生物还对药物代谢产生重要影响,为阐释中药作用机制提供了新的途径。     

双功能乙醛/乙醇脱氢酶AdhE参与细菌与宿主互作的机制研究进展

双功能乙醛/乙醇脱氢酶AdhE具有乙醛脱氢酶和乙醇脱氢酶的催化活性,是细菌乙醇厌氧发酵途径中的关键酶之一。近年,有关细菌与宿主相互作用的研究表明,AdhE在细菌适应宿主内环境变化和发挥毒力时具有重要的调控作用。本文对AdhE参与调控细菌感染宿主的致病机制和参与细菌对宿主免疫功能调节的作用机制进行综述,以期为AdhE的功能研究提供新的思路。     

胃肠道内分泌细胞及其激素

本文就15种胃肠道内分泌细胞的命名、超微结构特征、刺激分泌的因素及其产生激素的作用作简要的概述。胃肠道内分泌学是近年来最活跃领域之一,不但对老激素有更深入的了解和发现了好些新的激素,而且在激素的细胞定位上也有很大的进展。这对了解激素的生理意义和激素与临床关系上,无疑是有帮助的。     

磷脂酶D与病原微生物感染

磷脂酶D(phospholipase D,PLD)普遍存在于细菌,真菌以及哺乳动物中.在病原微生物中,PLD作为毒力决定因子在减数分裂、孢子形成等过程中起作用;在哺乳动物细胞中,PLD主要在胞膜转运、调节有丝分裂和细胞肌动蛋白骨架等一些信号转导中起作用.在病原菌感染宿主细胞的过程中,病原体和宿主细胞的PLD都被激活并发生级联反应,病原菌PLD可调节自身肌动蛋白丝的聚合和重排,并引起宿主细胞局部肌动蛋白丝的集聚,诱导宿主细胞对其吞噬.深入探讨PLD激活对感染发生的调控作用对透彻理解病原菌感染宿主细胞的分子机制具有重要意义.     

病原微生物感染破坏上皮细胞黏附连接的研究进展

上皮细胞具有高度规则的结构并为下层组织提供保护层,以防病原微生物侵入。上皮细胞排列整齐的结构基础是细胞间连接,一般是细胞间黏附分子形成的有规律连接复合物,如黏附连接(adherens junctions, AJs)。然而,为了破坏或穿越上皮屏障引起宿主感染,病原体通常采取各种策略靶向作用和调控黏附连接,如细菌通过靶向E-cadherin (E-钙黏蛋白)、β-catenin (β-连环蛋白)或细胞内信号通路破坏AJs,而病毒通过靶向E-cadherin或与nectin (黏连蛋白)相互作用侵入细胞。对病原微生物与黏附连接相互作用的机制研究,不仅能在细胞水平解释上皮屏障的基本生理特性,而且能阐明病原体侵入宿主的机制,为防治病原体感染提供新的思路和理论基础。     

微生物源抗菌肽研究概况

抗菌肽是广泛存在于生物体内的一种小分子多肽,具有分子量小、高效、稳定、作用机制独特和不易产生耐药性等特点,对细菌、真菌、寄生虫、病毒以及肿瘤细胞均有抑制作用。介绍了微生物来源,尤其是细菌源抗菌肽的结构特点、生物活性、作用机制及其在感染性疾病中的应用情况。     

益生菌调控幼龄畜禽消化道微生物研究进展

益生菌是一类对宿主(人类或动物)有益的活性微生物,包括细菌、真菌(如酵母)等,具有促进动物生长、提高免疫力的作用,是潜在的抗生素替代品。益生菌可能通过与动物消化道微生物互作来发挥益生作用,但具体机制仍不明确。综述了基于高通量测序技术研究益生菌调控幼龄畜禽(仔猪、雏鸡、反刍动物)消化道微生物群落组成的最新进展,并提出了未来研究方向,包括益生菌如何通过与消化道微生物互作影响其功能,益生菌对于幼龄畜禽不同健康状态下肠道微生物的影响,以及宿主因素如何影响益生菌对于幼龄畜禽消化道微生物的作用效果。     

玉米内生细菌资源研究进展

植物内生菌存在于植物的各个器官,种类繁多,对植物的生长发育具有重要作用。玉米是最重要粮食作物之一,通过研究玉米与其内生细菌的关系,对增产玉米以及生物防治有积极意义。本文归纳了玉米内生细菌资源的分离与收集,包括内生细菌的多样性及新种的鉴定;介绍了玉米内生细菌与宿主的相关性;总结了玉米内生细菌的生物学作用,包括抑菌性、耐受性、固氮作用和促生作用,以及内生细菌对玉米作用机制;并对玉米内生细菌研究趋势进行了前景展望,旨在为玉米内生细菌的研究提供参考。     

自噬与微生物感染

自噬作为一种维持胞内代谢稳态的机制,与机体微生物感染有着紧密的关系。一方面,自噬能够协助宿主清除病原体;而另一方面也有细菌通过进化,利用自噬体为其增殖提供必要条件,甚至在其中潜伏增殖。同时,病原体也可诱导过度自噬,促进细胞死亡。总之,自噬与微生物感染的关系,可能远比我们知道的复杂。本篇综述即是从自噬分子机制出发,寻找多种病原体与宿主细胞自噬之间的最新进展,深入探讨了自噬之于微生物感染的作用和意义。     

Recent advances in the study of Kaposi's sarcoma-associated herpesvirus replication and pathogenesis

It has now been over twenty years since a novel herpesviral genome was identified in Kaposi's sarcoma biopsies. Since then, the cumulative research effort by molecular biologists, virologists, clinicians, and epidemiologists alike has led to the extensive characterization of this tumor virus, Kaposi's sarcoma-associated herpesvirus(KSHV; also known as human herpesvirus 8(HHV-8)), and its associated diseases. Here we review the current knowledge of KSHV biology and pathogenesis, with a particular emphasis on new and exciting advances in the field of epigenetics. We also discuss the development and practicality of various cell culture and animal model systems to study KSHV replication and pathogenesis.     

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     

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.     

The structure, reproduction and taxonomy of Vidalia and Osmundaria (Rhodophyta, Rhodomelaceae)

Comprises species occurring mostly in subtidal habitats in tropical, subtropical and warm-temperate areas of the world. An analysis of the type species, V. spiralis (Sonder) Lamouroux ex J. Agardh, a species from Australia, establishes basic characters for distinguishing species in the genus. These characters are (1) branching patterns of thalli, (2) flat blades that may be spiralled on their axis, (3) width of the blade, (4) primary or secondary derivation of sterile and fertile branchlets and (5) position of sterile and fertile branchlets on the thalli. Application of the latter two characters provides an important basic method for separation of species into three major groups. Osmundaria , a genus known only in southern Australia, was studied in relation to Vidalia , and its separation from the Vidalia assemblage is not accepted. Species of Vidalia therefore are transferred to the older genus name, Osmundaria. Two new species, Osmundaria papenfussii and Osmundaria oliveae are described from Natal. Confusion in the usage of the epithet, Vidalia fimbriala Brown ex Turner has been clarified, and Vidalia gregaria Falkenberg, described as an epiphyte on Osmundaria pro/ifera Lamouroux, is revealed to be young branches of the host, Osmundaria prolifera.     

New or rare chromosome counts in Artemisia L. (Asteraceae, Anthemideae) and related genera from Kazakhstan

Fifteen chromosome counts of six Artemisia taxa and one species of each of the genera Brachanthemum, Hippolytia, Kaschgaria, Lepidolopsis and Turaniphytum are reported from Kazakhstan. Three of them are new reports, two are not consistent with previous counts and the remainder are confirmations of very scarce (one to four) earlier records. All the populations studied have the same basic chromosome number, x = 9, with ploidy levels ranging from 2x to 6x. Some correlations between ploidy level, morphological characters and distribution are noted.