海洋来源硫酸软骨素降解酶的研究进展

硫酸软骨素作为糖胺聚糖的一类,广泛分布于细胞膜表面及细胞基质中,参与了一系列生理和病理过程。硫酸软骨素的功能多样性与其结构多样性密切相关,而硫酸软骨素降解酶在硫酸软骨素/硫酸皮肤素构效关系研究中发挥了重要作用。该文结合笔者工作,全面阐述了目前商品化硫酸软骨素降解酶的种类、作用机制,以及近期在海洋细菌中发现和鉴定的硫酸软骨素降解酶。最后,对海洋来源硫酸软骨素降解酶进行了展望。     

壳聚糖基角膜细胞载体的制备及其细胞相容性

为探讨羟丙基壳聚糖基共混膜作为组织工程技术中角膜细胞培养载体的可行性, 分别制备了羟丙基壳聚糖/硫酸软骨素、羟丙基壳聚糖/明胶/硫酸软骨素以及羟丙基壳聚糖/氧化透明质酸/硫酸软骨素三种共混膜。测定其透光率、含水量和蛋白吸附性能; 在共混膜上培养兔角膜上皮细胞, 通过观察角膜上皮细胞在不同载体膜上的生长状态、贴附情况, 测定细胞活性以及上清液中乳酸脱氢酶的活性, 研究三种壳聚糖基载体膜片与角膜上皮细胞的相容性。膜片理化性质测定结果表明三种共混膜片具有良好的透明度, 适宜的含水量和较强的蛋白吸附性能; 细胞相容性实验结果表明羟丙基壳聚糖/明胶/硫酸软骨素共混膜对细胞的损伤最小, 有利于细胞在膜上的贴附和生长, 表现出良好的细胞相容性, 有望作为角膜细胞载体体外构建组织工程化角膜。     

Ⅱ型胶原-硫酸软骨素支架的制备及组织工程软骨的构建

研究经乙基-(3-二甲基氨基丙基)碳化二亚胺盐酸盐(EDC)处理的Ⅱ型胶原-硫酸软骨素支架材料的性能特点,并在体外构建组织工程软骨。从鸡软骨中提取Ⅱ型胶原,以不同浓度的EDC为交联剂通过冷冻干燥的方法制备Ⅱ型胶原与硫酸软骨素复合支架并测定其理化性质。将体外培养的新生兔关节软骨细胞接种在Ⅱ型胶原与硫酸软骨素复合支架上,观察软骨细胞在支架上的生长形态并检测支架上软骨细胞分泌的糖胺聚糖含量及Ⅱ型胶原含量。结果表明:采用EDC与硫酸软骨素交联增加了支架的稳定性,最适的交联剂质量浓度为7 mg/mL。软骨细胞在复合支架上增殖分化良好,并保持软骨细胞特异分化的表型,分泌Ⅱ型胶原与蛋白多糖(GAG)。培养14 d后已有软骨样组织形成。     

硫酸软骨素在癌症治疗领域的研究进展

硫酸软骨素是一种硫酸化的糖胺聚糖,其在恶性肿瘤组织中的含量、结构、硫酸化位点等与正常组织存在显著差异,在癌症的迁移,侵袭,血管生成过程中发挥重要调控作用,在癌症的临床研究中具有很大潜力。该文对硫酸软骨素的生物合成进行归类分析,对近几年硫酸软骨素与肿瘤入侵和转移的相关临床研究以及分子机制研究做出综述,以期为开发硫酸软骨素潜在的临床价值和肿瘤治疗靶点研究提供理论依据,为恶性肿瘤的早期诊断和预后评估提供思路。     

硫酸软骨素提取工艺的研究

硫酸软骨素是生物界广泛存在的酸性粘多糖,广泛存在于动物的器官软骨。以猪器官软骨为原料,采用碱提取和酶解相结合的方法提取硫酸软骨素,利用正交实验对碱提取过程中的温度,碱浓度以及提取时间等三个关键因素进行优化,并对硫酸软骨素成品的相关指标进行检测。正交实验结果表明,最佳的碱提取条件为：温度40℃、提取时间8h、碱提取浓度为0．15g／mL。在此条件下获得的碱提取液,通过酶解、脱色、醇沉、干燥,得到白色硫酸软骨素成品,总得率为20％,各项指标均符合国家部颁标准,达到出口要求。     

人血清脂蛋白与糖胺聚糖及人主动脉蛋白聚糖的相互作用

本文报道了在[Ca~(2+)]=30mmol/L时,人血清或人血清脂蛋白与各种糖胺聚糖(GAG)及人主动脉两种蛋白聚糖(PG)的相互作用。GAG与血清的作用能力为6—硫酸软骨素(C6—S)>肝素(Hep)>4—硫酸软骨素(C4—S)>透明质酸(HA)>硫酸皮肤素(DS)。极低密度脂蛋白(VLDL)及低密度脂蛋白(LDL)可与肝素作用形成不溶性复合物,而高密度脂蛋白(HDL)则不能。人主动脉硫酸软骨素—PG(CS—PG)、硫酸皮肤素—硫酸软骨素—PG(DS—CS—PG)与血清形成不溶性复合物的曲线类型不同,后者的类型似有利于DS—CS—PG与血清脂蛋白结合从而使之在动脉壁沉积。     

硫酸软骨素的提取和纯化分离技术

介绍了硫酸软骨素的来源、结构、性质及其生理功能,对硫酸软骨素的提取、纯化及分离技术进行了综述。     

硫酸软骨素研究现状

硫酸软骨素是从动物软骨中提取的黏性多糖,在医药、化妆品和食品工业上有广泛的用途,市场前景广阔。本对硫酸软骨素的性质和用途做了简要的介绍,并阐述了近几年硫酸软骨素生产工艺的发展状况。     

鹿茸硫酸软骨素蛋白聚糖的分离纯化研究

报道了用DEAE-纤维素(DE-23)离子交换柱层析从鹿茸二杠中分离、纯化及鉴定硫酸软骨素的方法.首先用适量蒸馏水浸泡鹿茸二杠并将其捣碎,离心取沉淀用盐酸胍浸提,浸提液对尿素液透析后经DEAE-纤维素(DE-23)离子交换柱层析,吸附大量的硫酸软骨素;再用含盐尿素溶液梯度洗脱、分离后,经软骨素酶消化及琼脂糖凝胶电泳, 与硫酸软骨素标准品比较,证实得到的物质为纯的硫酸软骨素蛋白聚糖,其得率约为48.77%.该方法使硫酸软骨素分离纯化一步完成,大大简化了纯化步骤.     

马氏珠母贝磺基转移酶PmCHST11基因的分子特征与表达分析

硫酸软骨素(CS)具有抗炎、抗病毒和软骨保护功能等免疫学功能。硫酸软骨素磺基转移酶CHST11(carbohydrate sulfotransferase 11,chondroitin 4)催化磺酸基从供体PAPS(3'-磷酸腺苷酰-5'-磷酸硫酸盐)转移到软骨素N-乙酰半乳糖胺的4位碳上,实现磺酸化反应,是合成硫酸软骨素的关键酶。本研究通过对马氏珠母贝磺基转移酶基因Pm CHST11(Pinctada martensii carbohydrate sulfotransferase 11)的全长克隆及组织表达分析,探究Pm CHST11在马氏珠母贝免疫调节中的作用。结果表明:Pm CHST11序列全长为1 418 bp,编码426个氨基酸;Pm CHST11序列含有信号肽结构区域,跨膜结构域和磺基转移酶-2结构域,为高尔基体膜偶联磺基转移酶;多序列比对结果显示,Pm CHST11与其它物种的CHST11同源性较低;实时荧光定量结果表明,Pm CHST11基因在多个组织中均有表达,其中在外套膜边缘区显著高表达(p0.05)。本研究为分析Pm CHST11在马氏珠母贝中的免疫调节中的作用积累基础资料。     

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.