治疗酶的研究进展

随着生物技术和现代药剂学研究的进展,酶类药物的应用取得了快速发展,已成为生物药物的一个重要门类。以下对治疗用酶的新品种、作用机理和新技术在治疗酶中的应用、酶作为药物靶点的应用等进行了回顾,并对未来治疗酶的发展方向进行了讨论。     

酶类药物现状、问题及展望

随着生物制药的迅速发展,许多酶类药物应运而生,在治疗代谢疾病、心血管疾病、癌症等诸多疾病上发挥着越来越重要的作用。但是酶类药物也存在一些不足,如潜在的免疫原性、较短的体内半衰期,以及较差的组织靶向性,影响了酶类药物的疗效和应用。为克服这些缺点,人们已开发出多种技术,如通过糖基化、聚乙二醇修饰等分子工程技术提升酶蛋白药效,另一方面酶基因疗法也已成功用于多种酶缺陷疾病的治疗。基于酶类药物的迅速发展和广泛的应用前景,本文对酶类药物的现状进行较详细的阐述,并对酶类药物的优势、所存在的问题及未来发展趋势进行分析和评述。     

蛇毒酶治疗心脑血管病的概述

蛇毒中含有十多种酶类及其它蛋白,其中蛇毒中的凝血酶样酶具有降解血浆纤维蛋白原,降低血浆粘度,降低血小板聚集等作用。经分离纯化的蛇毒酶制剂,在临床上广泛使用已20多年,积累了丰富的经验。现将蛇毒酶在心脑血管病中的应用情况概述如下。     

酶高效表达体系构建及高通量筛选关键技术

酶作为生物催化剂已被广泛地应用于医药、食品、化工、能源及轻工业等领域,随着低碳经济发展及绿色制造的发展需求,酶制剂应用领域不断拓展。随着当今生命科学前沿技术飞速发展,生物信息学、分子进化、基因组学和蛋白质组学等先进技术被应用于新酶分子的挖掘与改造。而代谢工程及反应过程工程成为酶制剂发酵生产调控的关键。同时,酶制剂高效表达菌株及其高通量筛选技术平台的构建也是新酶发现与工业化生产的重要桥梁。本文从酶高效表达载体和宿主出发,重点介绍了高效表达体系的构建原理和方法,包括重组酶表达载体表达元件的优化、重组酶基因表达量的增加、提高酶蛋白质的折叠通量、优化蛋白分泌运输途径、降低蛋白降解途径的作用、初级代谢途径的优化等。还总结了高效菌株的筛选方法,并展开合理预测。     

酶制剂在畜禽养殖中的应用研究进展

酶制剂作为生物催化剂具有专一性和高效性的特征,已被广泛应用于多个领域,其中酶制剂在畜禽养殖领域中的应用增长最快,且最具有潜力。酶制剂作为具有营养性添加剂和非营养性添加剂双重特性的饲料添加剂,不仅可以提高日粮营养消化利用率,还有调节动物肠道健康、杀菌抑菌等功能,在节约饲料资源、减少养殖排放、替代抗生素方面具有很大的市场潜力。本文综述了酶制剂在畜禽养殖行业中应用的不同阶段、不同酶种的功能定位及其研究进展。     

海洋微生物酶的开发

海洋酶（marizyme）制剂的开发将成为酶制剂工业一个较活跃的领域,应用前景广泛。海洋微生物是获取海洋酶的重要来源。美国一家公司已获得500种不同的海洋微生物分离物,成为筛选酶和药物的好材料,得到10种海洋生物酶如蛋白酶、琼脂糖酶和胶原酶等。海洋极端环境如海底火山口附近微生物产生的耐热酶有着开发潜力。美国研究人员从这种特殊环境火山口壁（105—113℃）找到嗜极微生物（exeemophiles）,如神rolobusfUI）larii的细菌能在这种高温环境中生长繁殖,在90℃以下则不能生长;还有一种在150℃下能生存的产甲烷大古单细胞生物如Met…     

多聚唾液酸对L-天冬酰胺酶的修饰及修饰酶特性研究

来源于大肠杆菌 (Ｅ .ｃｏｌｉ)的Ｌ 天冬酰胺酶是治疗淋巴性白血病和恶性淋巴肿瘤的有效酶制剂 ,已应用于临床。该酶与其他蛋白质类药物一样 ,在临床应用中存在两个常见问题 :一是酶制剂在体内易被降解 ,导致半衰期短 ;二是免疫原性。为了解决上述问题 ,人们用亲水性的大分子如血清蛋白、右旋糖苷和单甲氧基聚乙二醇 (ｍＰＥＧ)对该酶进行修饰。其中ｍＰＥＧ[1] 修饰后的Ｌ 天冬酰胺酶的抗原抗体结合能力完全消失 ,免疫原性下降 ,且体内半衰期延长 ;但酶活力只有天然酶的 8%～ 14% ,且ｍＰＥＧ在人体组织中无法降解 ,目前尚难评估长期使用…     

土壤酶学研究进展

自五十年代开始,土壤酶学的研究作为土壤微生物学的一个分支,引起人们对它的重视以来,每年都有大量有关土壤酶研究的文章发表,综述性文章也不少,而且还出版有专著。这些都大大推动了土壤酶学的发展,从最初只对少数几种酶的了解,到今天已扩展至发现和测定出土壤存在着五十多种酶类,同时在研究内容方面也更为深入。今天,一些土壤酶类的活性已被列为土壤学,土壤农业化学,土壤生物学和生态系统研究的重要测定项目。所谓土壤酶活性指的是:存在于土壤溶液中游离的酶活性,与土壤粘性矿物相结合的酶活性,与土壤有机胶体(腐殖     

植物组织培养的次生代谢产物Ⅶ.酶(过氧化物酶)

来自辣根(Armoracia rusticana)的过氧化物酶是用作临床检查用药剂,此外,由于酶反应灵敏的原故亦作为酶免疫测定及单克隆抗体的筛选测定(Screening assay)的检出用药剂,成为工业上各种用途的重要酶类之一。我们为考察用辣根植物细胞培养生产过氧化物酶的可能性,由辣根诱发出愈伤组织。     

海藻工具酶——褐藻胶裂解酶研究进展

从海洋生物中筛选提取有价值的酶类,开发海洋多糖降解产物,已成为海洋生物资源开发的一个重要方面。因此,近年来对于海藻工具酶之一的褐藻胶裂解酶及其降解产物——褐藻寡糖的研究日益受到人们的普遍关注。从褐藻胶裂解酶的来源、分类、底物专一性、作用方式及结构与机理研究、酶活力测定和酶学性质等方面,结合本课题组的研究工作综述近十年来有关褐藻胶裂解酶的研究进展。     

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.     

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.     

肝癌中HBV和HCV基因和抗原的分布及意义

采用原位分子杂交方法检测HCV RNA及HBV X基因;采用免疫组织化学方法研究HCV核心抗原,非结构区C33c抗原及HBxAg在肝细胞肝癌中的定位及分布.结果表明(1)HCV RNA、HBV X基因在肝细胞肝癌组织检出率分别为40%(55/136)和82%(112/136).HCV RNA定位于癌细胞的胞浆内,阳性细胞呈散在、灶状及弥漫分布三种形式;HBV X基因在肝癌细胞中的分布呈胞浆型、核型及核浆型,阳性细胞也呈上述三种分布形式;(2)HCV C33c抗原、核心抗原在肝细胞肝癌中的阳性率为81%(133/164)及86%(141/164).C33c抗原定位于癌细胞及肝细胞的胞浆内;核心抗原既定位于癌细胞核中,又可定位于胞浆中.C33c抗原阳性细胞以灶状分布为主;而核心抗原阳性细     

Selection with two alleles and complete dominance

For a plant selection model with frequency-independent viabilities, fertilities and selfing rates, it is shown that apart from global fixation, for certain parameter combinations a protected polymorphism and facultative fixation (either allele may become fixed according to initial frequencies) may both occur. Facultative fixation requires different selling rates for the dominant and recessive type. Protection of the polymorphism requires resource allocation for male and female function. In this connection the problem of purely genetically caused population extinction is discussed.
For general frequency dependence and regular segregation, the chances for establishment of a completely recessive gene are compared to those of a completely dominant gene. It is proven that the process of establishment of the recessive gene, despite a fitness advantage, may be considerably endangered by drift effects if random mating prevails. The recessive gene may reach the same effectivity in establishment as a dominant gene, only if the recessive homozygote mates exclusively with its own type during the period of establishment.