宏基因组学在微生物活性物质筛选中的应用

采用传统分离培养筛选微生物新活性物质的方法受到很大制约,自然界99%以上的微生物不能培养,其资源开发受到很大限制。环境微生物宏基因组技术应用避开了微生物分离纯培养问题,极大拓展了微生物资源的利用空间,增加获得新活性物质的机会和途径。本文着重介绍宏基因组的概念、研究策略包括DNA提取、文库构建与筛选等及在微生物活性物质筛选中的应用,并对宏基因组研究中存在的问题进行探讨。     

Pharmaceutically active secondary metabolites of marine actinobacteria

Marine actinobacteria are one of the most efficient groups of secondary metabolite producers and are very important from an industrial point of view. Many representatives of the order Actinomycetales are prolific producers of thousands of biologically active secondary metabolites. Actinobacteria from terrestrial sources have been studied and screened since the 1950s, for many important antibiotics, anticancer, antitumor and immunosuppressive agents. However, frequent rediscovery of the same compounds from the terrestrial actinobacteria has made them less attractive for screening programs in the recent years. At the same time, actinobacteria isolated from the marine environment have currently received considerable attention due to the structural diversity and unique biological activities of their secondary metabolites. They are efficient producers of new secondary metabolites that show a range of biological activities including antibacterial, antifungal, anticancer, antitumor, cytotoxic, cytostatic, anti-inflammatory, anti-parasitic, anti-malaria, antiviral, antioxidant, anti-angiogenesis, etc. In this review, an evaluation is made on the current status of research on marine actinobacteria yielding pharmaceutically active secondary metabolites. Bioactive compounds from marine actinobacteria possess distinct chemical structures that may form the basis for synthesis of new drugs that could be used to combat resistant pathogens. With the increasing advancement in science and technology, there would be a greater demand for new bioactive compounds synthesized by actinobacteria from various marine sources in future.     

Earthworms newly from Mongolia (Oligochaeta,?Lumbricidae,Eisenia)

Two new megadrile earthworms from the steppes, the first species wholly from Outer Mongolia, are ascribed to the partially parthenogenetic Eisenia nordenskioldi (Eisen, 1879) species-complex. Taxonomic justification of sympatric Eisenia nordenskioldi mongol and Eisenia nordenskioldi onon ssp. n. are supported by mtDNA COI barcodes. The unreliability of molecular differentiation based on voucher names compared to definitive types is again demonstrated, as pertains to the ultimate Eisenia andrei Bouché, 1972 synonym of the Eisenia fetida (Savigny, 1826) sibling species-complex composed of more than a dozen prior names. Similar species described from Northeast China [formerly Manchuria] and North Korea are briefly considered, albeit they are intermittently held in synonymy of cosmopolitan Aporrectodea rosea (Savigny, 1826) along with many other taxa including some exotic lumbricids initially found in India. Japanese and North American lumbricids are also mentioned. Distributions are discussed and an annotated checklist of all nine Siberian/sub-arctic Eisenia nordenskioldi ssp. is appended.     

海洋微生物资源及其产生生物活性代谢产物的研究

海洋微生物,尤其海洋细菌以其分类的多样性和规模而言,作为生物活性物质产生菌的潜力是巨大的。海洋微生物研究依据分离菌的生境来源可分为海水、沉积物、共栖、共生和深海菌群。生境的不同,不但影响菌群的分布,而且影响微生物代谢产物的合成。从报道的研究结果看,沉积物细菌、共栖细菌和共生细菌是海洋微生物天然药物筛选的重要来源。目前海洋微生物生物活性代谢产物资源的研究仍主要限制在那些在“标准”条件下易于生长和培养的微生物类群。本文对海洋微生物资源产生的生物活性物质的研究进展进行了综述。     

利用海洋硅藻生产生物活性物质研究进展*

生物活性物质在食品、饵料、化妆品、保健品和医药等行业具有广阔的应用前景,其研究早已受到广泛关注。鉴于海洋硅藻具有生长速度快、生物活性物质含量高、易于规模培养、便于提取等诸多优势,为理想的生物活性物质生产者。尽管国内外已进行了大量利用海洋硅藻生产生物活性物质的研究,但是受限于培养工艺老旧、生产成本过高等缺陷,商业化利用海洋硅藻开发生物活性物质依然停滞不前。阐述海洋硅藻五种常见生物活性物质的应用价值,进一步探讨海洋硅藻高产生物活性物质的策略,就如何低成本、高效开发利用硅藻源生物活性物质提出建议,为海洋硅藻商业化开发利用提供参考。     

海洋细菌活性物质的研究进展

由于海洋细菌有产生多种新颖独特的生物活性物质的巨大潜力,使其成为新药筛选的重要资源,在药品开发研究中具有良好的发展前景。综述了海洋细菌中具有药物开发前景的活性物质的研究和应用现状及其存在的问题。     

Cell cultures from marine invertebrates: obstacles, new approaches and recent improvements

The establishment of cell lines from marine invertebrates has been encountered with obstacles. Contrary to insects and arachnids where the development of a variety of cell lines has become routine, there is no single established cell line from marine invertebrates. This review examines the activity in the field of marine invertebrate cell cultures within the last decade (1988–1998). During this period, attempts (90 peer reviewed studies in addition to many other abstracts, chapters in books, symposia presentations and reports) were limited to a few species within only six phyla (Porifera, Cnidaria, Crustacea, Mollusca, Echinodermata, Urochordata; in addition to freshwater/terrestrial annelids and platyhelminths). These studies which are summarized here, on one hand indicated ubiquitous problems and on the other, unique characterizations to each phylum studied. Only one-third of the studies revealed cultures of 1 month or longer but most of these were long-term cultures found or suspiciously considered to be contaminated by other unicellular eukaryotic organisms, mainly by thraustochytrids. Three unique approaches/obstacles for marine invertebrate cell cultures (source of cell, cryopreservation and eukaryotic contaminants) are further discussed. The overall impact of recent improvements and developed protocols raises the suggestion for testing different, novel routes in the establishment of cell cultures from marine invertebrates.     

小单孢菌属的分类及应用研究

小单孢菌在自然界分布广泛,但由于分离、分类方法所限,绝大多数还没有被人们所认识。在小单孢菌的分类学研究中,最初主要依据的是形态特征、培养特征及生理生化特征等表观分类学指征,随着“多相分类”的广泛应用,分子分类在小单孢菌的分类学研究中起到了越来越重要的作用。小单孢菌是寻找新的生物活性物质的重要菌源,某些种能产生抗生素,如庆大霉素、利福霉素、新霉素等;某些种能降解天然橡胶和纤维素。近年来的研究表明,小单孢菌能产生具有独特化学结构的生物活性物质,对肿瘤细胞有靶向和识别作用,并能有效地杀死肿瘤细胞。     

Do new reconstructions clarify the relationships between the Phanerozoic diversity dynamics of marine invertebrates and long-term eustatic trends?

A relationship between global sea levels and the diversity of marine invertebrates throughout the Phanerozoic remains an urgent matter for debates. Its recognition depends on a proper selection of diversity and eustatic curves. A comparison of changes in the revised sample-standardized generic diversity and long-term global sea-level changes provides a weaker evidence for a direct covarying relationship than established earlier, although the eustatic control on diversity dynamics of marine invertebrates was important during ∼74% of the Phanerozoic. Multiple causation of biodiversity changes, data bias, erroneous reconstructions, and conceptual misinterpretations are likely explanations of observed difference between the new biodiversity and eustatic curves.     

青藏高原红景天属植物药材中五种有效成分HPLC分析(英文)

为了比较红景天属不同红景天药材的有效成分的差异,采用HPLC-DAD法建立了同时测定青藏高原14种红景天属药材中红景天苷、酪醇、没食子酸、儿茶素、表儿茶素含量的方法.色谱柱为Phenomenex Luna C18(250×4.6 mm,5μm);以甲醇-水为流动相,梯度洗脱;流速为1.0 mL/min;检测波长为276 nm;柱温为30℃。结果表明,在五种化合物在选定的条件下能得到较好的分离,线性关系良好。方法回收率在97.36%以上,RSD小于2.31%。该方法简单快速,可为红景天属药材的质量控制提供科学依据。     

海洋微生物及海藻抗HIV天然产物研究进展

艾滋病是当今重大的公共卫生问题和社会问题。从天然资源寻找新抗HIV活性天然产物是新药发现的重要途径。综述了来源于海洋微生物、海藻具抗HIV活性的天然产物以及抗H1V活性天然产物筛选方法和靶点。     

假交替单胞菌及其胞外生物活性物质研究进展

假交替单胞菌是新建立的一个海洋细菌属,它独特的生物学特性引起了越来越多研究的关注。简介了假交替单胞菌的分类地位、生态分布等特点,重点阐述了假交替单胞菌生物活性物质的种类及其生物活性,最后对假交替单胞菌的应用前景进行了展望。     

Microencapsulation of purple Brazilian cherry juice in xanthan,tara gums and xanthan-tara hydrogel matrixes

The purple Brazilian cherry (Eugenia uniflora L.) juice was encapsulated in xanthan, tara and xanthan-tara hydrogel matrixes. Encapsulation efficiency, Differential Scanning Calorimetry (DSC), X-ray diffractometry, release profile, stability of carotenoids, phenolic compounds and antioxidant activity of microparticles were evaluated. Encapsulation was confirmed. The highest encapsulation efficiency was obtained with xanthan gum and hydrogel was mostly indicated for the release of carotenoids in GFS and IFS medium. Phenolic compounds had the highest release rate but not in a gradually way, regardless of wall material and fluids under analysis. Stored microparticles at 4 and 25 °C, showed carotenoid degradation. Xanthan and hydrogel wall material provided the greatest stability to these compounds. The microparticles’ anti-oxidant activity decreased during storage due to the degradation of carotenoids.     

Biodiversity and potentials of marine-derived microorganisms

The marine environment is a prolific resource for the isolation of less exploited microorganisms. As a matter of fact, in the sea, untapped habitats exist with unique characteristics. In addition, the potential contribution of marine sources to the discovery of new bioactive molecules was recently recognized. Biosearch Italia possesses a collection of about 40 000 microorganisms, isolated from different ecological niches. In the search of new bioactive entities, investigations were expanded to marine habitats including marine sediments and organisms. More then 800 microorganisms have been isolated. About half belong to fungal genera, the others being actinomycetes. The frequency of antibiotic activities produced by these marine strains has been determined. Initial data are encouraging: marine isolates produce antibiotic activities with frequencies comparable to terrestrial ones. These activities probably represent a mixture of novel metabolites and known products previously discovered from terrestrial isolates. Further investigations are ongoing to assess the novelty of these observed microbiological activities.     

Leaf litter breakdown budgets in streams of various trophic status: effects of dissolved inorganic nutrients on microorganisms and invertebrates

1. We investigated the effect of trophic status on the organic matter budget in freshwater ecosystems. During leaf litter breakdown, the relative contribution of the functional groups and the quantity/quality of organic matter available to higher trophic levels are expected to be modified by the anthropogenic release of nutrients. 2. Carbon budgets were established during the breakdown of alder leaves enclosed in coarse mesh bags and submerged in six streams: two oligotrophic, one mesotrophic, two eutrophic and one hypertrophic streams. Nitrate concentrations were 4.5–6.7 mg L⁻¹ and the trophic status of each stream was defined by the soluble reactive phosphorus concentration ranging from 3.4 (oligotrophic) to 89 μg L⁻¹ (hypertrophic). An ammonium gradient paralleled the phosphate gradient with mean concentrations ranging from 1.4 to 560 μg L⁻¹ NH₄‐N. The corresponding unionised ammonia concentrations ranged from 0.08 to 19 μg L⁻¹ NH₃‐N over the six streams. 3. The dominant shredder taxa were different in the oligo‐, meso‐ and eutrophic streams. No shredders were observed in the hypertrophic stream. These changes may be accounted for by the gradual increase in the concentration of ammonia over the six streams. The shredder biomass dramatically decreased in eu‐ and hypertrophic streams compared with oligo‐ and mesotrophic. 4. Fungal biomass increased threefold from the most oligotrophic to the less eutrophic stream and decreased in the most eutrophic and the hypertrophic. Bacterial biomass increased twofold from the most oligotrophic to the hypertrophic stream. Along the trophic gradient, the microbial CO₂ production followed that of microbial biomass whereas the microbial fine particulate organic matter and net dissolved organic carbon (DOC) did not consistently vary. These results indicate that the microorganisms utilised the substrate and the DOC differently in streams of various trophic statuses. 5. In streams receiving various anthropogenic inputs, the relative contribution of the functional groups to leaf mass loss varied extensively as a result of stimulation and the deleterious effects of dissolved inorganic compounds. The quality/quantity of the organic matter produced by microorganisms slightly varied, as they use DOC from stream water instead of the substrate they decompose in streams of higher trophic status.