虫生真菌的多样性

虫生真菌分属菌物界各分类阶元,它们除在物种上种类繁多外,在形态结构、生活史、繁殖方式、致病机理和次生代谢产物方面亦极具多样化。了解虫生真菌的多样性对正确鉴定它们的分类地位,探明疾病发生的侵染单元,以及多方位,多层次地利用虫生真菌的功能和次生代谢产物具有重要的学术意义和实用价值     

耐盐菊芋块茎内生真菌次生代谢产物的分离与结构鉴定

盐生植物菊芋(Helianthus tuberosus)是一种新型经济作物,特殊生境可能会使其内生真菌产生特殊的次生代谢产物,如结构新颖或活性显著的化合物.为研究这种耐盐植物内生真菌的次生代谢产物以及植物宿主和内生真菌之间可能存在的关系,本实验室从耐盐菊芋块茎中分离纯化出10株内生真菌,对这10株内生真菌进行抗卤虫活性筛选,初步筛选出1株抗卤虫活性良好的菌株Mucor sp.ht-7,规模发酵后通过提取分离技术得到7个化合物,用波谱手段鉴定了7个化合物的结构,对这株内生真菌和宿主次生代谢产物之间的关系进行分析探讨,并对化合物生物活性加以分析.     

虫草及相关真菌的次生代谢产物及其活性

全面系统地总结了目前在虫草及相关真菌中次生代谢产物研究方面的最新成果,发现目前在虫草及其密切相关的虫生真菌中共报道272个有具体结构的化合物,其活性涉及杀虫、抗癌、抗菌、免疫调节和抗疟原虫等多方面。这些化合物主要来源于20余种虫草、虫草无性型或与虫草密切相关的虫生真菌。虽然近年来有关虫草中生物活性代谢物的研究受到世界各国广泛关注,但仍有90%以上虫草及相关虫生真菌种类中尚无任何具体成分的研究报道,因此有关研究尚需要进一步深入。     

虫草及相关真菌的次生代谢产物及其活性

全面系统地总结了目前在虫草及相关真菌中次生代谢产物研究方面的最新成果,发现目前在虫草及其密切相关的虫生真菌中共报道272个有具体结构的化合物,其活性涉及杀虫、抗癌、抗菌、免疫调节和抗疟原虫等多方面。这些化合物主要来源于20余种虫草、虫草无性型或与虫草密切相关的虫生真菌。虽然近年来有关虫草中生物活性代谢物的研究受到世界各国广泛关注,但仍有90%以上虫草及相关虫生真菌种类中尚无任何具体成分的研究报道,因此有关研究尚需要进一步深入。     

虫草及相关真菌的次生代谢产物及其活性

全面系统地总结了目前在虫草及相关真菌中次生代谢产物研究方面的最新成果,发现目前在虫草及其密切相关的虫生真菌中共报道272个有具体结构的化合物,其活性涉及杀虫、抗癌、抗菌、免疫调节和抗疟原虫等多方面。这些化合物主要来源于20余种虫草、虫草无性型或与虫草密切相关的虫生真菌。虽然近年来有关虫草中生物活性代谢物的研究受到世界各国广泛关注,但仍有90%以上虫草及相关虫生真菌种类中尚无任何具体成分的研究报道,因此有关研究尚需要进一步深入。     

座壳孢及其有性型（子囊菌门）代谢产物研究进展

座壳孢及其有性型是一类重要的虫生真菌,隶属子囊菌门、粪菌纲、肉座菌目、麦角菌科,能寄生粉虱和蚧类昆虫,可开发成一种环境友好型的生物农药。座壳孢及其有性型属成员广泛分布于热带和亚热带地区,该类群物种、栖息环境和生态适应的多样性使它们的代谢产物化学结构及其生物活性彰显出多样性特点,结构和功能多样的真菌代谢产物已成为发现新药先导化合物的重要资源。虫生真菌因其独特的生活方式和多种生存环境形成了与众不同的适应寄主特性及代谢通路,明显提高获得新颖结构、显著活性的代谢产物的几率,目前已是药物重点研发的领域。在座壳孢及其有性型代谢产物研究中已报道了萜类、黄酮类、醌类、环肽和甾醇等多种化合物,并具有抗肿瘤、抗疟疾、抗菌和杀虫等多种生物活性,可在农业、工业和医药保健等方面应用。本文对近年座壳孢及其有性型代谢产物的化学成分和生物活性等方面的研究进展进行概述,为促进座壳孢及其有性型代谢产物的深入研究、开发利用和新药创制提供参考。     

枯草芽孢杆菌J-15抗大丽轮枝菌次生代谢产物对棉田土壤真菌多样性的影响

【背景】目前利用拮抗菌进行作物病害防治的研究较多,但拮抗菌次生代谢产物如何影响棉花根际土壤微生物群落相关的研究较少。【目的】探讨枯草芽孢杆菌J-15抗大丽轮枝菌次生代谢产物对棉田土壤真菌多样性的影响,为利用枯草芽孢杆菌J-15及其次生代谢产物防治棉花黄萎病的土壤微生物生态安全进行评估。【方法】以新疆北部玛纳斯地区棉田为土壤采样点,随机选取10个点进行采样后混合,经枯草芽孢杆菌J-15抗大丽轮枝菌次生代谢产物处理一定时间后,提取土样总DNA,利用Illumina HiSeq高通量技术,对样品中真菌ITS1-ITS2区进行高通量测序,分析J-15抗大丽轮枝菌次生代谢产物处理对土样真菌多样性的影响。【结果】在97%相似度水平下,处理10、30d后,样品中真菌的OTU数量、Chao1和ACE丰度指数均分别高于相同时间放置的未处理的对照组,而Simpson指数低于其对照组。从群落组成分析来看,与对照组相比,受J-15次生代谢产物处理的土壤样品,子囊菌门(Ascomycota)的盘菌属(Tricharina)和被孢霉门(Mortierellomycota)的被孢霉属(Mortierella)等优势真菌相对丰度提高,而丰度高于1%的2类病原真菌轮枝孢属(Verticillium)、镰孢霉属(Fusarmm)的丰度显著降低。【结论】J-15抗大丽轮枝菌次生代谢产物对棉田土壤真菌群落及丰度有显著影响,但不改变影响农业生产的土壤真菌群落的结构。     

林木内生真菌研究进展

研究林木内生真菌及其次生代谢产物具有重要的生态学和经济学意义。国内外对多种林木内生真菌作了大量的相关报道。作者就近年来有关林木内生真菌的多样性研究、生态学作用以及次生代谢产物的应用前景方面的研究作一综述,以期更好地利用林木内生真菌为农业和医药业服务。     

真菌次生代谢产物多样性及其潜在应用价值

从生物间的协同进化和微生物次生代谢产物的功能意义原理出发,本文侧重介绍了与植物和昆虫密切相关的一些真菌及其次生代谢产物在医药和农用新药物开发应用中的潜在价值。     

青蒿内生真菌研究进展

植物内生真菌可以产生与宿主植物相同或相似的次生代谢产物,已成为活性化合物生产和发现新化合物的重要来源。为了解青蒿内生真菌的潜在应用价值,介绍了青蒿内生真菌的生物多样性、生物活性和部分次生代谢产物,并展望了未来的研究方向,以期为进一步开发利用青蒿内生真菌提供参考。     

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.