地衣及其内生真菌活性次级代谢产物研究进展

地衣是一种独特的菌藻共生体,能够在荒漠、高山、冻土等恶劣环境生存,具有特殊的生理结构和独特的生存环境.地衣及其内生真菌能够产生结构新颖、活性广泛的次级代谢产物,研究地衣及其内生真菌次级代谢产物对新型药用资源开发以及利用等方面都具有重要的意义.本文关注了近年来地衣及其内生真菌的次级代谢产物相关研究,并对其生物活性方面的研...     

我国资源植物化学与天然产物化学基础研究的现状与发展

本文从生物活性成分的筛选与分离、植物次生代谢产物生物合成及其分子调控、环境因子对植物次生代谢产物合成和积累的影响、植物体内生菌与植物次生代谢产物的关系等方面介绍了我国资源植物化学与天然产物化学领域基础研究的现状与发展。     

放线菌基因组与生物技术

天蓝色链霉菌全基因组序列的公布 ,对目前工业生产生物活性代谢产物菌株的遗传改造 ,构建生产高价值药物的超级菌 ,以及由微生物资源去寻找新的生物活性代谢产物将产生巨大影响。文中就基因组时代如何发展由基因组信息和化合物库预测次生代谢路径、研究功能基因组学时代的放线菌次生代谢调控、基因工程技术在放线菌抗生素生产中的应用以及体外分子定向进化与分子育种等生物技术问题进行文献综述。     

茉莉酸甲酯对丹参毛状根有效成分含量的影响

研究茉莉酸甲酯对丹参毛状根中次生代谢产物含量的影响,为丹参毛状根培养的生产应用提供实验依据。以茉莉酸甲酯作为丹参毛状根的诱导子,进行丹参毛状根诱导培养。发现茉莉酸甲酯诱导的丹参毛状根的丹参酮类化合物丹参酮Ⅰ和丹参酮ⅡA分别是无茉莉酸甲酯诱导的1.53倍和1.16倍,酚酸类化合物迷迭香酸和丹酚酸B分别是无茉莉酸甲酯诱导的1.37倍和4.43倍。茉莉酸甲酯能显著提高丹参毛状根次生代谢产物的合成和积累,通过茉莉酸甲酯诱导实现丹参有效次生代谢产物的高效生产。     

中国地衣学现状综述

本文对中国地衣学在多样性、系统性及其物种与基因资源生物学研究方面进行了综述。文中强调了多样性和系统性研究在自然界地衣资源与研究开发之间的桥梁作用。论述了地衣结皮固沙、固碳及其基因资源在沙漠生物地毯工程中的意义。揭开了不产次生代谢产物的地衣秘密及其破解途径。     

荚孢腔属真菌次生代谢产物的研究进展

荚孢腔属(Sporormiella)真菌,属于座囊菌纲格孢腔菌目荚孢腔菌科(Sporormiaceae),种类较多,目前已收载了87种。研究发现,该属真菌的次生代谢产物资源丰富,迄今已报道的新化合物就有近50个,包括生物碱及含氮类、聚酮类、萜及甾体等化合物,其中已发现一些结构新颖、生物活性独特的化合物,为药物的研发提供了潜在的先导化合物,具有很好的研究价值。然而,目前对该属真菌的次生代谢产物研究的报道还较少,为使该属真菌资源能引起人们的关注和更多认识,本文对荚孢腔属真菌次生代谢产物的化学结构及其生物活性的研究进展进行了较为全面的综述。     

粘细菌次生代谢产物中大环类化合物的研究进展

粘细菌可以产生多种次生代谢产物,是继放线菌、芽胞杆菌之后的第3大类次级代谢产物产生菌。本文综述了粘细菌次生代谢产物中大环类化合物的研究进展。首先介绍了粘细菌中分离的主要大环类化合物种类、结构特征及来源菌株;然后分别从抗肿瘤、抗菌、抗病毒等几方面对其生物活性进行概述;最后对粘细菌次生代谢产物中大环类化合物的相关研究工作进行了展望。     

深海真菌Neoroussoella sp.固体发酵物中次生代谢产物及其生物活性研究

研究深海真菌Neoroussoella sp.FS526的次生代谢产物及生物活性.采用硅胶柱、Sephadex LH-20凝胶柱和高效液相等多种色谱技术对菌株FS526的固体发酵物中的次生代谢产物进行分离纯化,并通过NMR等波谱方法鉴定化合物结构.从菌株FS526中共分离鉴定了15个化合物,分别为amestolkoli...     

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。     

咖啡酸及其主要衍生物的研究进展及开发前景

咖啡酸(caffeic acid)及其衍生物是一类在植物中分布非常广泛的次级代谢产物,它们普遍存在于一些食物中,如水果、蔬菜、谷物等,在一些天然药物中也含有这一类活性成分,如丹参中水溶性的丹酚酸类成分,当归中的阿魏酸、咖啡酸,金银花中的绿原酸等。近年来,咖啡酸及其衍生物的生物活性引起了人们的广泛关注,其新的生物活性正在不断被发现。作为一类普遍存在于植物中的次生代谢产物,咖啡酸及其衍生物的资源丰富,而目前其资源利用率还非常低,一些富含咖啡酸及其衍生物的天然植物没有被充分利用。本文旨在总结近年来国内外对于咖啡酸及其衍生物的生物活性及构效关系的研究进展,分析其开发利用前景。     

Tree Species Composition Predicts Epiphytic Lichen Communities in an African Montane Rain Forest

The ecology of many tropical rain forest organisms, not the least in Africa, remains poorly understood. Here, we present a detailed ecological study of epiphytic lichens in the equatorial montane rain forest of Bwindi National Park (331 km²), Uganda. We evaluated all major lichen growth forms, including selected groups of crustose lichens. In 14 transects at elevations of 1290 m to 2500 m, we sampled 276 trees belonging to 60 species. We recorded all lichen species on each tree trunk between ground level and 2 m above the ground, yielding 191 lichen species in 67 genera, with a mean of 4.7 species per tree. We used non‐metric multi‐dimensional scaling to separate epiphytic lichen assemblages according to tree species composition and elevation. Structural equation modeling indicated that elevation influenced tree species composition and that tree species composition largely determined lichen species composition. Thus, elevation acted indirectly on the lichen assemblages. Further studies examining factors such as bark properties and lichen colonization ecology may clarify what determines the association between tree species and lichen assemblages. The link between lichen assemblages and large‐scale elevation patterns, as well as disturbance and regrowth histories, warrants further study. An analysis of lichen species composition on individual tree species that occur over large elevation ranges would distinguish the effect of tree species on lichen assemblages from the effect of elevation and thus climate. Our study highlights the limited extent of our knowledge of tropical epiphytic lichens.     

Lichen diversity on dolmen and menhir in the Megalithic complex of Sa Coveccada (Mores,Sardinia)

This work describes the lichen diversity found on the megalithic Dolmen of Sa Coveccada (Mores, Sardinia) until 2010. After that year, a restoration with chemical removal of lichen crusts took place, which destroyed a great part of the lichen communities. These were studied again after removal and lichen communities occurring on rock outcrops in the surroundings of the Dolmen and on a contiguous menhir were investigated as well for comparison. Before the restoration, 33 species had been recorded on the Dolmen, most being crustose, followed by foliose and fruticose forms. Among these, eight species are regarded as rare in Sardinia and five rare at lower elevations. Most of the recorded species are typical for eutrophic substrates and for meso- to xerophytic conditions. Studies on lichen diversity on archaeological monuments in Sardinia are limited. This is the first report on the lichens of a Sardinian dolmen. This paper questions whether the lichen diversity of such monuments should be preserved as lichens have been an important part of the monument ecosystem and of the landscape for many centuries. This work also aims to improve collaboration among lichen and monument experts, in order to avoid hasty restoration decisions.     

肉疣衣属中国新记录种——乌普萨拉肉疣衣

采用形态解剖、化学、生态类型及地理成分分析等传统分类方法对新疆天山南部巴音布鲁克山区地衣外部形态和内部构造、地衣附属结构、地衣繁殖器官进行观察。利用显色反应法(CT)、微量化学结晶法(MCT)、薄层层析法(TLC)等生物化学方法,鉴定地衣次生代谢产物,发现了1个中国新记录种:乌普萨拉肉疣衣[Ochrolechia upsaliensis(L.)A.Massal]。文中描述了该新记录种地衣的形态解剖、化学特征和生境,并提供了地衣体、子囊及子囊孢子的彩色图片。     

LICHENS OF SKOMER ISLAND,WEST WALES

Skomer Island, a National Nature Reserve, lies off the West coast of Wales. This small island holds lichen communities of international importance associated with large populations of seabirds. Saxicolous lichen communities are described, 248 species listed and details given of a base-line monitoring programme, which will provide data on changes in the lichen flora over time and distinguish cyclical from permanent deleterious changes. Threats to island populations are discussed, such as the likely effects of oil pollution following the Sea Empress accident in February 1996.     

Functional diversity and traits assembly patterns of lichens as indicators of successional stages in a tropical rainforest

Understanding community assembly patterns with regard to functional traits, which may be common to different species, allows us to compare ecological communities in a wider range of environmental and phytogeographic conditions. Moreover, a functional approach may facilitate the comprehension of the relation between biotic changes and ecosystem functions in complex systems such as tropical forests. Considering the lack of information in relation to the influence of environmental conditions on lichen functional traits, on lichen functional patterns in tropical forests and the potential usage of this approach in bioindication studies, this paper aims at (i) determining the functional structure of the lichen communities along the forest succession gradient, (ii) assessing the relation of lichen functional traits to this gradient and (iii) verifying the potential of using lichen functional traits as indicators of successional stages in tropical rainforests. Lichens were sampled in 24 sampling units of three successional stages (6–10; 12–20; and 40–60 years of recovering). The results corroborated our main hypothesis that the functional structure of the lichen communities responds to structural changes along a forest regeneration gradient. Growth forms (foliose, fruticose and crustose) as well as some reproductive trait states (lirella, isidia and perithecia) were the most suitable lichen traits to be used as indicators of forest succession in the southern edge of the Atlantic Rainforest. Lirella, fruticose and foliose were more related to earlier successional stages; isidia was more related to intermediate stages, while perithecia and crustose were more related to older stages. These results reinforce the ability of lichens to be used as bioindicators of forest conditions.     

The weight of the crust: Biomass of crustose lichens in tropical dry forest represents more than half of foliar biomass

In recent years, our ecological knowledge of tropical dry forests has increased dramatically. However, the functional contributions of whole ecosystem components, such as lichens, remain mostly unknown. In these forests, the abundance of epiphyte crustose lichens is responsible for the characteristic white bark on most woody plants, conspicuous during the dry season, but the amount of resources that the lichen component represents remains unexplored. We estimated lichen biomass in a Mexican tropical dry forest using the bark area of trees, the dry mass of lichens per unit area and the percentage of bark covered by lichens, together with previously known tree densities. The lowest 2.5 m of the forests main trunks contained 188 kg/ha of lichen biomass, with lichens covering 85% of the available bark for trees <12 cm DBH and 38% for trees >12 cm. Total epiphytic lichen biomass was 1.34–1.99 Mg/ha. Lichen biomass represented 61% of the foliar biomass in the forest. To our knowledge, this is the first time that a lichen biomass estimate is provided for an ecosystem in which crustose lichens are the dominant lichen growth form. Crustose lichens are typically considered to contribute little to the total lichen biomass and to be difficult to include in ecological analyses. The high lichen biomass in this ecosystem implies a significant ecological role which so far is unexplored. We suggest the crustose lichen component should not be underestimated a priori in ecological studies, especially in ecosystems with abundant lichen cover.     

ITS2 metabarcoding analysis complements lichen mycobiome diversity data

Lichen thalli harbor complex fungal communities (mycobiomes) of species with divergent trophic and ecological strategies. The complexity and diversity of lichen mycobiomes are still largely unknown, despite surveys combining culture-based methods and high-throughput sequencing (HTS). The results of such surveys are strongly influenced by the barcode locus chosen, its sensitivity in discriminating taxa, and the depth to which public sequence repositories cover the phylogenetic spectrum of fungi. Here, we use HTS of the internal transcribed spacer 2 (ITS2) to assess the taxonomic composition and diversity of a well-characterized, alpine rock lichen community that includes thalli symptomatically infected by lichenicolous fungi as well as asymptomatic thalli. Taxa belonging to the order Chaetothyriales are the major components of the observed lichen mycobiomes. We predict sequences representative of lichenicolous fungi characterized morphologically and assess their asymptomatic presence in lichen thalli. We demonstrated the limitations of metabarcoding in fungi and show how the estimation of species diversity widely differs when ITS1 or ITS2 are used as barcode, and particularly biases the detection of Basidiomycota. The complementary analysis of both ITS1 and ITS2 loci is therefore required to reliably estimate the diversity of lichen mycobiomes.     

Secondary chemistry of cultured mycobionts: formation of a complete chemosyndrome by the lichen fungus of Lobaria spathulata

Abstract:The study aimed to optimize culture conditions and nutrient requirements for the production of secondary metabolites by the cultured mycobiont Lobaria spathulata. This species proved to be an excellent model system for such studies, as the complete chemosyndrome found in the natural lichen thallus was repeatedly formed in the cultured mycobiont with differentiated, aerial mycelia. Nutrient media containing the disaccharide, sucrose, were found to favour both rapid growth and the production of typical lichen substances. Higher proportions of the secondary compounds were detected in the developing mycobiont than in mature lichen thalli.     

Do tree-related factors mediate the response of lichen functional groups to eutrophication?

In the last decades, the pollution regime has been drastically changed in most industrialized countries, with a considerable decrease in sulphur dioxide (SO₂) emissions and an increasing relevance of eutrophication compounds, such as nitrogen compounds and particulate matter. This situation hampers the interpretation of data in biomonitoring surveys, as high lichen diversity is not always associated with good air quality. The objective of this study was to test whether the effects of eutrophication on the abundance of different lichen functional groups varies according to some tree-related factors. We analysed the relationships between epiphytic lichen diversity, emissions of main atmospheric pollutants and tree characteristics (circumference and bark pH, light transmitted through the canopy). Hierarchical partitioning of variance and Generalized Linear Mixed Models (GLMM) confirmed that lichen functional groups with different nitrogen tolerances responded to several atmospheric pollutants, with both independent and joint effects, whereas they did not show significant differences depending on main tree-related factors. We demonstrated that, under high eutrophication levels, differences in bark pH did not significantly differentiated the composition of epiphytic lichen communities.     

The phenolic compounds in <Emphasis Type="Italic">Cladonia</Emphasis> lichens are not antimicrobial in soils

According to classic text books on lichen biology, the phenolic secondary chemicals in lichens have antibiotic effects on soil microorganisms and mycorrhizal fungi in ecosystems. However, the experimental evidence for this under natural conditions is still relatively scarce. We examined some of the assumptions behind the concept of antimicrobial effects of lichen secondary substances: (1) the secondary substances of Cladonia stellaris, usnic and perlatolic acids, are leached out from the lichens by rainwater; (2) these substances inhibit the microbial activity of soil, and; (3) since they are extremely resistant to microbial decomposition, the soil underneath a continuous lichen mat is enriched in usnic and perlatolic acids. Our results did not support any of these assumptions. The evidence for the antimicrobial activity of lichen secondary substances seems to be weak in comparison to other suggested functions such as light filtering and herbivore protection. We suggest that it is time to re-evaluate the evidence for the antimicrobial ecological role of lichen secondary substances in natural systems.