生物化学教学中“聚糖与医学”相关内容的引入与探讨

聚糖在生理、病理中作用机制的阐释使聚糖与医学的相关性得到重视,聚糖结构的变化常与疾病直接相关。生物化学作为生物相关专业的重要基础课程,其教学内容也应该引入新的科研成果,与时俱进。目前各个版本的生物化学课本并未涉及“聚糖与医学”相关知识,本文对“聚糖与医学”相关内容在生物化学教学中的引入进行了探讨,并对肿瘤等疾病中的异常聚糖以及聚糖在疾病治疗和诊断中的应用等引入内容进行了具体阐述。“聚糖与医学”相关内容的引入符合“基础与临床”相结合的教学理念,有利于增加学生对科研前沿的了解,提升学生的科研素养和核心竞争力。     

蛋白质的糖基化作用分类及相关数据库

真核细胞中的许多蛋白质是糖蛋白,其寡糖链以共价键连接到特定的氨基酸残基上。糖蛋白糖链的生物学功能是通过糖链对蛋白质功能的修饰、糖缀合物糖链与蛋白质的识别来实现的,糖基化是生物体最常见最主要的蛋白质修饰作用之一。糖链结构及其功能和调控的复杂性制约了其研究的速度,随着生物信息学的快速发展,糖生物学领域的数据库和预测软件也脱颖而出,该文介绍糖基化作用和糖生物学领域的数据库与预测软件。     

糖生物学:生命科学中的新前沿

１．糖类研究的历史回顾糖类的研究已有百年的历史,许多研究成果表明,糖类是生物体内除蛋白质和核酸以外的又一类重要的生物分子,尤其是一类重要的信息分子。１．１糖类和血型众所周知,血型在输血、组织和器官的移植以及法医鉴定中是必须注意的。人类的主要血型是ＡＢ...     

细胞核质中的糖生物学

在细胞核质中也存在着多种类型的复合糖类。其中部分来自细胞外或内质网,另有一些是细胞核质中特有的。概述了细胞核质中两种特有的糖基化,O-N-乙酰氨基葡萄糖基化和ADP-核糖基化,以及相关的糖生物学。     

糖生物信息学数据库

糖生物信息学是在糖生物学和糖组学发展的基础上,结合计算机技术,对生命活动过程中,参与糖链及与其相互作用的蛋白质等分子研究所产生的数据进行获取、储存、解析、模拟以及预测等内容的综合学科.糖生物信息学数据库是糖生物信息学发展到一定阶段,对糖组学等研究中产生的数据进行专门储藏与查询的应用工具.目前国际互联网中存在近百个糖生物信息学相关数据库,涉及内容包括糖链结构、参与糖链合成的基因或者蛋白质、糖结合蛋白、代谢通路、糖链或相互作用蛋白质等分子三维结构,或糖组学实验结果等领域.本文将归纳总结糖生物信息学数据库,为现有研究提供帮助.     

糖微阵列技术在糖组学研究中的进展

聚糖多以蛋白质和脂配基形式存在,在生物体内的信息传递、细胞识别和蛋白质折叠等生物过程中具有十分重要作用,是继核酸和蛋白质之后被发现的第三类生物信息分子.但聚糖结构复杂,并存在大量异构体,无法象DNA一样进行合成和测序.根据聚糖分子能够与凝集素或糖结合蛋白特异性结合,提出并发展了糖微阵列技术.此技术在聚糖结构与功能研究中已显示出优越性.通过对糖微阵列构建方式及检测方法的探讨,对近些年来糖微阵列技术的发展进行了综述.     

糖类的生物信息学资源

生物信息学在推动遗传学和蛋白质科学的研究领域中,已发挥了举足轻重的作用.相比较而 言,糖科学产生的信息还比较有限,随着人们对糖类分子的关注,糖生物学的发展也出现新 的契机,其信息正在飞速地增长.对已经获得的糖类相关知识进行系统整合就显得越来越有 必要,许多研究型数据库和免费工具已应运而生,并且数目在不断扩大,正成为科学工作者 非常便利的工具.但到目前为止,许多数据库或者网络预测工具在文献中很少提及或难以找 到,给研究者带来了不少的麻烦.部分原因是数据库资源本身数据不断在更新,人机界面也 变得越方便和人性化,另外就是人们对于这些新型的研究工具了解较少.这篇综述介绍了 目前网络上最常用的糖类生物信息学资源,包括糖的一级结构,分析测试数据、构象,酶, 凝集素,糖蛋白等方面的各种数据库.     

多组学技术及其在生命科学研究中应用概述

随着新一代测序技术、高分辨质谱技术、多组学整合分析方法及数据库的发展,组学技术正从传统的单一组学向多组学技术发展。以多组学驱动的系统生物学研究将带来生命科学研究的新范式。本文简要概述了基因组学、表观基因组学、转录组学,蛋白质组学及代谢组学的进展,重点介绍多组学技术平台的组成和功能,多组学技术的应用现状及在合成生物学及生物医学等领域的应用前景。     

同步辐射圆二色谱及其在糖生物学及生物分子中的应用

同步辐射圆二色谱与普通圆二色谱相比,特点在于向真空紫外波段（〈200nm）拓展,以及同步辐射所提供的高强度紫外和真空紫外光源。糖的圆二色谱结构主要在200nm以下。蛋白质和核酸在200nm以下的真空紫外范围,也具有丰富的光谱结构。因此向真空紫外拓展,伴随新的电子跃迁,对应新的光谱结构,包含更丰富的结构信息,确定的结构种类就越多和越精确。同步辐射高强度的真空紫外光源,是获得高质量真空紫外圆二色谱数据的保证,为糖及糖蛋白、蛋白质和核酸研究提供了溶液中结构探测新的实验方法。综述同步辐射圆二色谱特点及其在结构生物学中的应用,以及新发展的蛋白质圆二色谱数据库（PCDDB）。介绍已对外开放的北京同步辐射实验室同步辐射圆二色谱探测,及其在蛋白质、糖和核酸研究中的应用,以及基于微流控混合芯片的亚毫秒动态探测发展。     

N-聚糖和O-聚糖在极性化细胞蛋白质分拣中的作用

极性化上皮细胞的质膜因其所含蛋白质、脂质等组分不同,可以分为细胞膜顶端和细胞膜基底侧端两个区域,而新合成的蛋白质向这两个区域的有效分拣是上皮细胞维持其自身极性及正常功能所必需的。细胞膜基底侧端蛋白质的分拣主要由位于该蛋白质胞质区的信号肽所介导,关于这方面的研究是比较深入的;而细胞膜顶端蛋白质的分拣机制目前尚未阐明,因而显得比较复杂。近年来,糖类分子作为生物体内细胞识别和调控过程的信息分子日益受到关注,人们通过干扰聚糖合成、基因突变以及构建糖基化缺陷细胞株等实验方法,逐渐地认识到糖类分子在极性化上皮细胞的蛋白质分拣调节中起重要作用。由于糖分子本身结构非常复杂,而且目前缺乏研究糖类分子的有效手段,使得糖生物学的研究远远落后于蛋白质和核酸的研究。从而导致探讨糖类分子在蛋白质分拣过程的具体机制相对来说比较困难。本综述拟简要概括糖类分子中N-聚糖和O-聚糖在极性化上皮细胞的蛋白质分拣过程中的作用,以及两种聚糖在此过程中行使分拣信号功能的可能机制。     

An Overview of a Wide Range of Functions of ZnT and Zip Zinc Transporters in the Secretory Pathway

Zinc plays essential roles in the early secretory pathway for a number of secretory, membrane-bound, and endosome/lysosome-resident enzymes. It enables the enzymes to fold properly and become functional, by binding as a structural or catalytic component. Moreover, zinc secreted from the secretory vesicles/granules into the extracellular space has a pivotal role as a signaling molecule for various physiological functions. Zinc transporters of the Slc30a/ZnT and Slc39a/Zip families play crucial roles in these functions, mediating zinc influx to and efflux from the lumen of the secretory pathway, constitutively or in a cell-specific manner. This paper reviews current knowledge of the ways these two zinc transporters perform these tasks by manipulating zinc homeostasis in the secretory pathway. Recent questions concerning zinc released into the cytoplasm from the secretory pathway, which then functions as an intracellular signaling molecule, are also briefly reviewed, emphasizing zinc transporter functions.     

The Xenopus Cell Cycle: An Overview

Oocytes, eggs and embryos from the frog Xenopus laevis have been an important model system for studying cell-cycle regulation for several decades. First, progression through meiosis in the oocyte has been extensively investigated. Oocyte maturation has been shown to involve complex networks of signal transduction pathways, culminating in the cyclic activation and inactivation of Maturation Promoting Factor (MPF), composed of cyclin B and cdc2. After fertilisation, the early embryo undergoes rapid simplified cell cycles which have been recapitulated in cell-free extracts of Xenopus eggs. Experimental manipulation of these extracts has given a wealth of biochemical information about the cell cycle, particularly concerning DNA replication and mitosis. Finally, cells of older embryos adopt a more somatic-type cell cycle and have been used to study the balance between cell cycle and differentiation during development.     

世界生物资源概况

生物资源是地球生物多样性的核心组成部分,是人类生存和发展的战略性资源。合理利用和保护日趋濒危的生物资源是世界各国当务之急。本文概述了生物资源的概念、重要性和基本特征,介绍了世界生物资源物种数目、管理利用情况及濒危现状,对我国生物资源的保护具有一定参考价值。     

An Overview: The Diversified Role of Mitochondria in Cancer Metabolism

Mitochondria are intracellular organelles involved in energy production, cell metabolism and cell signaling. They are essential not only in the process of ATP synthesis, lipid metabolism and nucleic acid metabolism, but also in tumor development and metastasis. Mutations in mtDNA are commonly found in cancer cells to promote the rewiring of bioenergetics and biosynthesis, various metabolites especially oncometabolites in mitochondria regulate tumor metabolism and progression. And mutation of enzymes in the TCA cycle leads to the unusual accumulation of certain metabolites and oncometabolites. Mitochondria have been demonstrated as the target for cancer treatment. Cancer cells rely on two main energy resources: oxidative phosphorylation (OXPHOS) and glycolysis. By manipulating OXPHOS genes or adjusting the metabolites production in mitochondria, tumor growth can be restrained. For example, enhanced complex I activity increases NAD⁺/NADH to prevent metastasis and progression of cancers. In this review, we discussed mitochondrial function in cancer cell metabolism and specially explored the unique role of mitochondria in cancer stem cells and the tumor microenvironment. Targeting the OXPHOS pathway and mitochondria-related metabolism emerging as a potential therapeutic strategy for various cancers.     

The Toxicology of PCB's—An Overview for Clinicians

Polychlorinated biphenyls (PCB''s) have low acute toxicity but are of public health concern because of their persistence in the environment, the bioaccumulation in human and animal tissues, and their potential for chronic or delayed toxicity.Although many questions remain unanswered, it is clear that occupational exposure, at a minimum, can produce dermatologic effects and liver dysfunction. The long half-life of PCB''s and their presence in various human tissues leaves open the possibility of substantial chronic and delayed effects analogous to those seen in animals. PCB''s are potent inhibitors of reproductive function in both rodents and nonhuman primates and produce liver tumors in animal cancer bioassays. As potent inducers of hepatic enzyme systems, PCB''s may have additional unpredictable long-term health effects.These effects have only recently begun to be studied in a rigorous manner, and although the epidemiological evidence is neither complete nor entirely consistent, there can be no question of the necessity to keep human exposures to the lowest feasible levels.     

Genomic Overview and Biological Functions of Exopolysaccharide Biosynthesis in Bifidobacterium spp.

For many years, bacterial exopolysaccharides (EPS) have received considerable scientific attention, mainly due to their contribution to biofilm formation and, above all, because EPS are potential virulence factors. In recent times, interest in EPS research has enjoyed a welcome boost thanks to the discovery of their ability to mediate communication processes with their surrounding environment and to their contribution to host health maintenance. In this review, we provide a fresh perspective on the genetics and activity of these polymers in members of the Bifidobacterium genus, a common gut inhabitant of humans and animals that has been associated with several health-promoting effects. Bifidobacteria can use EPS to protect themselves against the harsh conditions of the gastrointestinal tract, thus improving their persistence in the host. Indeed, the relevant function of EPS for bifidobacteria is underlined by the fact that most genomes sequenced until now contain genes related to EPS biosynthesis. A high interspecies variability in the number of genes and structural organization is denoted among species/subspecies; thus, eps clusters in this genus do not display a consensus genetic architecture. Their different G+C content compared to that of the whole genome suggests that eps genes have been acquired by horizontal transfer. From the host perspective, EPS-producing bifidobacteria are able to trigger both innate and adaptive immune responses, and they are able to modulate the composition and activity of the gut microbiota. Thus, these polymers seem to be critical in understanding the physiology of bifidobacteria and their interaction with the host.     

Phytoremediation—An Overview

The use of plants (directly or indirectly) to remediate contaminated soil or water is known as phytoremediation. This technology has emerged as a more cost effective, noninvasive, and publicly acceptable way to address the removal of environmental contaminants. Plants can be used to accumulate inorganic and organic contaminants, metabolize organic contaminants, and encourage microbial degradation of organic contaminants in the root zone. Widespread utilization of phytoremediation can be limited by the small habitat range or size of plants expressing remediation potential, and insufficient abilities of native plants to tolerate, detoxify, and accumulate contaminants. A better understanding and appreciation of the potential mechanisms for removing contaminants from the root zone and the interaction between plants, microorganisms, and contaminants will be useful in extending the application of phytoremediation to additional contaminated sites.     

An Overview of Epigenetic Assays

A significant portion of ongoing epigenetic research involves the investigation of DNA methylation and chromatin modification patterns seen throughout many biological processes. Over the last few years, epigenetic research has undergone a gradual shift and recent studies have been directed toward a genome-wide assessment. DNA methylation and chromatin modifications are essential components of the regulation of gene activity. DNA methylation effectively down-regulates gene activity by addition of a methyl group to the five-carbon of a cytosine base. Less specifically, modification of the chromatin structure can be carried out by multiple mechanisms leading to either the upregulation or down-regulation of the associated gene. Of the many assays used to assess the effects of epigenetic modifications, chromatin immunoprecipitation (ChIP), which serves to monitor changes in chromatin structure, and bisulfite modification, which tracks changes in DNA methylation, are the two most commonly used techniques. J. T. DeAngelis and W. J. Farrington are contributed equally.     

An Overview of Fishing Rights

Coastal state management of marine harvests within 200-mile Exclusive Economic Zones was a new and innovative process during the period from the late 1970s through the 1980s. The spread of conservation-focused harvest management was a key step in the evolution of fishing rights, followed in some nations by a second step of creating more exclusive, individual or group fishing rights. The three main forms of more exclusive fishing rights – limited entry permits, individual fishing quotas (IFQs), and local community-based or co-operative harvesting – vary widely in content and detail. But, when successful, they all increase the economic efficiency of fisheries, and they reshape the economic and political landscape of fisheries. All three types, but particularly IFQs, may initiate radical changes in the economic organization of the fishery, ultimately changing who fishes, where and when they fish, the products sold, the balance of power among industry sectors, incentives to support conservation, the size of incomes from fishing, and the location of shore-side economic activity. Changes of this sort are bound to provoke controversy. The controversies over fishing rights take three forms: disagreements over the meaning and intent of fishing rights, disputes over the distribution of rights and associated economic gain, and concern for disruptions imposed on people who are dependent on the “old order”. This paper provides a short review of the underlying concepts, rights systems, and current controversies concerning fishing rights.