广西北部湾放线菌的分离筛选及活性产物的鉴定

为从广西北部湾的泥样和植物中分离海洋放线菌,筛选具有抑菌活性的菌株,分离活性化合物。研究采用普通稀释法分离菌株,对发酵产物进行抑菌活性测试,利用活性追踪分离活性化合物,并通过波谱方法确定化合物结构。结果表明从6个海泥样品和3个植物样品中共分离73株放线菌,筛选得到具有抑香蕉枯萎病和金黄色葡萄球菌活性的菌株7株,并从其中的1株链霉菌 Streptomyces sp.MDCW-126的次级代谢产物中分离鉴定了星形孢菌素。从广西北部湾分离的药用活性菌株资源具有开发和深入研究价值。     

二氢乳清酸脱氢酶的结构特征和催化循环研究进展

二氢乳清酸脱氢酶是黄素依赖的线粒体酶,它催化嘧啶从头合成的第4步反应,将二氢乳清酸氧化为乳清酸。通过选择性抑制二氢乳清酸脱氢酶,从而抑制嘧啶的合成,已被开发用于治疗癌症、自身免疫性疾病、细菌或病毒感染以及寄生虫疾病等。抑制剂的开发需详细了解二氢乳清酸脱氢酶的结构特征和催化循环机制。因此,文中主要从这两个方面进行了综述,并展望了该酶的抑制剂在临床应用中的前景。     

红海榄根际土壤来源的泡盛曲霉（Aspergillus awamori）F12及其代谢产物的抗菌活性分析

摘要：【目的】鉴定一株来自于红海榄根际土壤并具有分泌抑菌活性代谢产物的真菌菌株F12,并从其发酵液乙酸乙酯浸膏中分离抑菌活性成分。【方法】通过形态学观察以及ITS序列分析方法对菌株F12进行鉴定;利用色谱技术分离发酵液乙酸乙酯浸膏中的次生代谢产物,根据化合物的质谱、氢谱、碳谱以及理化性质确定其结构,并检测它们对细菌生长的抑制作用。【结果】菌株F12被鉴定为Aspergillus awamori strain F12;从其发酵液乙酸乙酯浸膏中分离到3种化合物：1,4-二甲氧基苯（1）、大黄素（2）和3,6-二苯甲基哌嗪-2,5-二酮（3）,其中化合物1属于在本属真菌中首次报道。化合物2对金黄色葡萄球菌和枯草芽孢杆菌的生长具有明显的抑制作用,最低抑菌浓度（MIC）分别为16ng/L和32ng/L,化合物1和3对上述菌株的生长无明显的抑制活性。【结论】首次发现从红海榄根际土壤中分离到的泡盛曲霉（Aspergillus awamori）菌株F12具有合成1,4-二甲氧基苯和大黄素的能力,其中后者对微生物的生长具有明显的抑制作用。     

土壤中拮抗菌株铜绿假单胞菌HBD-12次级代谢产物的分离鉴定及其体外抗菌抗肿瘤活性检测

为从土壤中筛到具有抗菌和抗肿瘤等生物活性的菌株,以孕烯醇酮作为唯一碳源进行筛菌,经分子生物学鉴定及菌株发酵液抑菌活性测定,发现一株铜绿假单胞菌HBD-12对大肠杆菌、苏云金芽孢杆菌、指状青霉、意大利青霉具有较好抑菌效果。运用柱层析法分离纯化该菌株发酵液成分,采用波谱法解析所得单体化合物结构,并使用HTRF激酶检测试剂盒测定其抗肿瘤活性。结果显示:分离得到的单体化合物1-羟基-9,10-二氮杂菲和3-羟基-9,10-二氢二氮杂菲均具有显著的抗肿瘤活性。在浓度为20μg/mL时,1-羟基-9,10-二氮杂菲和3-羟基-9,10-二氢二氮杂菲对Aurora激酶A的抑制率分别为78.39%±2.29%和60.34%±8.35%。由此可见该菌株的次级代谢产物对新型抗菌、抗肿瘤药物的研发具有很好的利用价值。     

四种植物内生真菌的分离及其抗肿瘤活性的筛选

从银杏、合欢、臭椿和苦楝的树皮中分离到61株内生真菌。MTT法检测显示在45.9%的菌株发酵液粗提物在200 μg/mL时对人食道癌细胞EC109的生长抑制率大于50%。其中6株内生真菌(YX5, YX17, YX36, KL1, CC1, CC5)在50 μg/mL时仍具有较高的细胞毒活性, 且活性成分主要分布在菌株的发酵液中。合欢内生真菌中的活性菌株比例最小, 在50 μg/mL时均未显示任何对EC109细胞的抑制作用。银杏中的高活性菌株比例最大, 占银杏内生真菌的15.8%。银杏分离菌株YX5的活性最为突出, 其发酵液粗提物对3种肿瘤细胞EC109, HONE1和HeLa的抑制率IC50分别是18.3 μg/mL、3.6 μg/mL和6.5 μg/mL。研究结果表明, 作为抗肿瘤药物的潜在来源银杏内生真菌值得关注。     

微生物来源的HLE抑制剂N01WA-735E的研究

人白细胞弹性蛋白酶抑制剂为筛选炎症和癌症的重要靶点。应用白细胞弹性蛋白酶抑制剂高通量的筛选模型对数千株放线菌进行筛选,发现了阳性菌株N01 WA-735。首先通过形态学和化学分类学鉴定其为链霉菌属。采用有机溶剂提取、硅胶柱色谱、Sephadex LH-20柱色谱和结晶等方法对该菌株的发酵产物进行了分离纯化,得到活性单体化合物N01 WA-735E,通过对N01 WA-735E的理化性质和波谱数据分析,确定其结构与文献报道的化合物BE-52440A相同。该化合物对人白细胞弹性蛋白酶有很强的抑制活性,其IC50为3.02μmol/L。该化合物对人白细胞弹性蛋白酶的抑制活性国内外未见报道。     

抗多重耐药病原菌的越南槐内生菌TRPH-35的抗菌活性及其鉴定

以大肠杆ATCC25922、金黄色葡萄球菌ATCC25923及其临床多重耐药分离株ETEC-AD9、MRSA-DF12共4株人体病原细菌为靶标菌,采用琼脂块法从越南槐内生真菌中筛选抗菌活性菌株,并以改良的微量肉汤稀释法测定其代谢产物的最小抑菌浓度;根据形态和分子特征鉴定拮抗菌株的分类学地位。结果表明,菌株TRPH-35的活菌块对各病原细菌的抑菌圈直径与阳性对照相当;其代谢产物对各病原菌的最小抑菌浓度为20~40μg/mL;初步鉴定该菌株为刺盘孢。本研究结果表明,菌株TRPH-35鉴定为刺盘孢,对参试病原细菌均显示强的抗菌活性,具有较大的开发应用潜力。     

微生物来源的HLE抑制剂N01WA-735E的研究

人白细胞弹性蛋白酶抑制剂为筛选炎症和癌症的重要靶点。应用白细胞弹性蛋白酶抑制剂高通量的筛选模型对数千株放线菌进行筛选,发现了阳性菌株N01WA-735。首先通过形态学和化学分类学鉴定其为链霉菌属。采用有机溶剂提取、硅胶柱色谱、Sephadex LH-20柱色谱和结晶等方法对该菌株的发酵产物进行了分离纯化,得到活性单体化合物N01WA-735E,通过对N01WA-735E的理化性质和波谱数据分析,确定其结构与文献报道的化合物BE-52440A相同。该化合物对人白细胞弹性蛋白酶有很强的抑制活性,其IC50为3.02μmol/L。该化合物对人白细胞弹性蛋白酶的抑制活性国内外未见报道。     

叶状蔷薇珊瑚来源真菌Parengyodontium album SCSIO 40430次级代谢产物研究

【背景】海洋来源真菌次级代谢产物由于具有化学结构新颖和生物活性多样的特点,是药物发现新的源泉之一。【目的】研究Parengyodontium album SCSIO 40430次级代谢产物及其抑菌活性。【方法】利用常压柱色谱、半制备HPLC等色谱学方法对P.albumSCSIO40430发酵液粗提物进行分离纯化;通过HR-ESI-MS、1H、13CNMR等光谱学方法,并结合文献数据,确定其产生的化合物结构;对分离得到的化合物进行抑菌活性测试。【结果】分离到3个苯并二氢吡喃酮类化合物,结构确定为Deoxyphomalone(1)、2-Ethyl-3,5-dihydroxy-11-methylchroman-9-one (2)、2-Ethyl-3-hydroxy-5-methoxy-11-methylchroman-9-one (3)。【结论】获得3个苯并二氢吡喃酮类化合物;活性测定结果显示化合物2对耐甲氧西林金黄色葡萄球菌(MRSAATCC43300)、苏云金芽孢杆菌(B.thuringiensisSCSIOBT01)有较好的生长抑制活性(MIC 16μg/mL)。     

马蜂肠道菌抑制反枝苋的活性筛选及菌株MF06的活性代谢产物

摘要:【目的】研究马蜂肠道真菌对反枝苋的抑制活性,为开发微生物源除草剂奠定基础。【方法】通过测试11种肠道真菌发酵液对反枝苋根生长的抑制效果筛选出活性菌株MF06。通过形态学观察和分子生物学鉴定确定MF06的分类地位。通过硅胶柱层析法、薄层层析法、葡聚糖凝胶柱层析法对乙酸乙酯粗提物进行分离、纯化,得到代谢产物1,研究代谢产物1对反枝苋根生长的抑制作用。利用核磁共振谱和质谱确定代谢产物1的化学结构。【结果】经形态学观察和ITS序列分析确定MF06菌株为尖孢镰刀菌(Fusarium oxysporum)。当供试质量浓度为100 μg/mL时,该菌株发酵液的乙酸乙酯提取物对反枝苋根生长的抑制率大于68%。从乙酸乙酯粗提物中分离得到代谢产物1,经过结构鉴定为镰刀菌酸与9,10-脱氢镰刀菌酸以1:1比例形成的混合物。活性测试表明代谢产物1对反枝苋根生长具有很强的抑制作用,抑制活性的IC50值为(0.51±0.18)μg/mL,与阳性对照药2,4-二氯苯氧乙酸的活性［IC50值为(0.30±0.14)μg/mL］相当。【结论】MF06菌株具有开发为微生物源除草剂的潜力。     

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.