不同居群不同部位头花蓼总黄酮含量研究

以原产贵州、四川的10个头花蓼收集系为材料,采用紫外分光光度法,研究了各头花蓼收集系植株不同部位总黄酮含量的变异,以便找出总黄酮含量较高的头花蓼收集系及其头花蓼植株上总黄酮含量较高的部位,为头花蓼药业提供指导。结果表明,不同部位头花蓼总黄酮含量差异很大,其含量大小依次为老茎>花>嫩叶>老叶>嫩茎。头花蓼老茎、花中总黄酮含量在不同居群间差异显著,其它部位差异不显著。四川都江堰居群老茎总黄酮含量最高,达2.761%,显著高于其它收集系。     

Microbiota within the perennial ice cover of Lake Vida, Antarctica

Lake Vida, located in the McMurdo Dry Valleys, Antarctica, is an 'ice-sealed' lake with approximately 19 m of ice covering a highly saline water column (approximately 245 ppt). The lower portions of the ice cover and the lake beneath have been isolated from the atmosphere and land for circa 2800 years. Analysis of microbial assemblages within the perennial ice cover of the lake revealed a diverse array of bacteria and eukarya. Bacterial and eukaryal denaturing gradient gel electrophoresis phylotype profile similarities were low (<59%) between all of the depths compared (five depths spanning 11 m of the ice cover), with the greatest differences occurring between surface and deep ice. The majority of bacterial 16S rRNA gene sequences in the surface ice were related to Actinobacteria (42%) while Gammaproteobacteria (52%) dominated the deep ice community. Comparisons of assemblage composition suggest differences in ice habitability and organismal origin in the upper and lower portions of ice cover. Specifically, the upper ice cover microbiota likely reflect the modern day transport and colonization of biota from the terrestrial landscape, whereas assemblages in the deeper ice are more likely to be persistent remnant biota that originated from the ancient liquid water column of the lake that froze.     

基因组规模代谢网络模型构建及其应用

微生物制造产业的发展迫切需要进一步提高认识、设计和改造微生物细胞代谢的能力,以推动工业生物技术快速发展。随着微生物全基因组序列等高通量数据的不断积聚和生物信息学策略的持续涌现,使全局性、系统化地解析、设计、调控微生物生理代谢功能成为可能。而基于基因组序列注释和详细生化信息整合的基因组规模代谢网络模型(GSMM)构建为全局理解和理性调控微生物生理代谢功能提供了最佳平台。以下在详述GSMM的应用基础上,描述了如何构建一个高精确度的GSMM,并展望了未来的发展方向。     

Alleviation of Both Water and Nutrient Limitations is Necessary to Accelerate Ecological Restoration of Waste Rock Tips

Hard rock quarries are commonly located close to national parks and special areas of conservation and are generally regarded as visually intrusive. Consequently, restoration strategies that effectively accelerate natural plant regeneration processes are required. Slate waste tips present extreme conditions for plant establishment with multiple potential limiting factors (e.g., lack of organic matter, nutrients, and poor water retention). In this study, we investigated ecological strategies to accelerate natural regeneration at the largest slate quarry in Europe. A field experiment was conducted to assess ecosystem restoration using a contrasting set of native woody species. Treatments included amendments of waste tips with: polyacrylamide gel to increase water‐holding capacity; mineral fertilizer to increase nutrient supply; and two treatments that increased both (organic waste or boulder clay addition). Ecosystem recovery was evaluated through above‐ and below‐ground productivity (plant and microbial, respectively) and soil analyses. Neither increasing nutrient supply (with mineral fertilizer) nor water‐holding capacity (with polyacrylamide gel) was sufficient, alone, to improve plant establishment. However, both boulder clay and organic waste amendment significantly enhanced plant growth. There was a marked positive interaction in the effects on tree growth of the amendment with organic waste and boulder clay. Large interactions occurred between tree species and substrate amendments. The growth of N₂‐fixing species was strongly favored over non‐fixers where there was no addition of material increasing soil nitrogen supply, whereas the growth advantage of pioneer species over non‐pioneers was greatest with fertilizer, organic waste, or clay additions. Organic waste addition had the greatest positive impact on soil processes.     

Diversity of halophilic microorganisms: Environments,phylogeny, physiology,and applications

The phylogenetic diversity of microorganisms living at high salt concentrations is surprising. Halophiles are found in each of the three domains: Archaea, Bacteria, and Eucarya. The metabolic diversity of halophiles is great as well: they include oxygenic and anoxygenic phototrophs, aerobic heterotrophs, fermenters, denitrifiers, sulfate reducers, and methanogens. The diversity of metabolic types encountered decreases with salinity. The upper salinity limit at which each dissimilatory process takes place is correlated with the amount of energy generated and the energetic cost of osmotic adaptation. Our understanding of the biodiversity in salt-saturated environments has increased greatly in recent years. Using a combination of culture techniques, molecular biological methods, and chemotaxonomic studies, we have obtained information on the nature of the halophilic Archaea as well as the halophilic Bacteria that inhabit saltern crystallizer ponds. Several halophilic microorganisms are being exploited in biotechnology. In some cases, such as the production of ectoine, the product is directly related to the halophilic behavior of the producing microorganism. In other cases, such as the extraction of β-carotene from Dunaliella or the potential use of Haloferax species for the production of poly-β-hydroxyalkanoate or extracellular polysaccharides, similar products can be obtained from non-halophiles, but halophilic microorganisms may present advantages over the use of non-halophilic counterparts. Journal of Industrial Microbiology & Biotechnology (2002) 28, 56–63 DOI: 10.1038/sj/jim/7000176 Received 20 May 2001/ Accepted in revised form 20 June 2001     

Quantitative Properties of Random Amplified Polymorphic DNA (RAPD)

Random Amplified Polymorphic DNA analysis (RAPD) is a methodology that has been used as a tool for monitoring microbial communities. To be useful in this application RAPD, and any other methodology, must show properties that allows for the detection of quantitative changes in composition of the microbiota. Therefore, the objective of this study was to establish whether RAPD possesses such properties. The strategy was to use genomic DNA, extracted from a set of tertiary bacterial mixtures defined according to an experimental mixture design, and containing varying proportions of Escherichia coli, Bacillus subtilis, and Pseudomonas CF600. RAPD-PCR was performed on the mixed DNA extracts and the amplified DNA fragments were separated on sequencing gels to produce genomic fingerprints that were digitized and modeled by Partial Least Squares regression (PLS). Significant predictions were obtained using an external test set for validation, with Root Mean Square Error of Predictions (RMSEP) of 0.21, 0.19 and 0.20 for the proportion of E. coli, B. subtilis and Pseudomonas CF600 respectively. Taken together, the results showed that RAPD patterns quantitatively represented the initial mixture proportions. Therefore, the view that RAPD could be useful for whole microbial community monitoring was strengthened.     

Microbial diversity of boron-rich volcanic hot springs of St. Lucia, Lesser Antilles

The volcanic Sulphur Springs, St. Lucia, present an extreme environment due to high temperatures, low pH values, and high concentrations of sulfate and boron. St. Lucia offers some unique geochemical characteristics that may shape the microbial communities within the Sulphur Springs area. We chose six pools representing a range of geochemical characteristics for detailed microbial community analyses. Chemical concentrations varied greatly between sites. Microbial diversity was analyzed using 16S rRNA gene clone library analyses. With the exception of one pool with relatively low concentrations of dissolved ions, microbial diversity was very low, with Aquificales sequences dominating bacterial communities at most pools. The archaeal component of all pools was almost exclusively Acidianus spp. and did not vary between sites with different chemical characteristics. In the pool with the highest boron and sulfate concentrations, only archaeal sequences were detected. Compared with other sulfur springs such as those at Yellowstone, the microbial diversity at St. Lucia is very different, but it is similar to that at the nearby Lesser Antilles island of Montserrat. While high elemental concentrations seem to be related to differences in bacterial diversity here, similarities with other Lesser Antilles sites suggest that there may be a biogeographical component as well.     

益生菌Lactobacillus casei Zhang固态发酵条件的优化

利用一株分离自传统发酵酸马奶中的益生干酪乳杆菌（Lactobacillus casei Zhang）进行固态发酵（Solid State Fermentation,SSF）。以发酵物中的活菌数为主要指标,采用九因素四水平（L32（4^9））的正交试验优化固态发酵培养基,并在优化的培养基基础上研究不同的初始含水量及培养时间对Lactobacillus casei Zhang活菌数的影响。实验结果表明,在固态发酵培养基组成为4g豆粕、5g麸皮、0．6g乳清粉、0．3g葡萄糖、0．3g碳酸钙、0．02g硫酸铵、0．01g硫酸镁,初始含水量为55％的优化条件下,37℃发酵60h,发酵物中Lactobacillus casei Zhang活菌数可达到4．08×10^10CFU／g。     

Fe- and S-Metabolizing Microbial Communities Dominate an AMD-Contaminated River Ecosystem and Play Important Roles in Fe and S Cycling

Indigenous Fe- and S-metabolizing bacteria play important roles both in the formation and the natural attenuation of acid mine drainage (AMD). Due to its low pH and Fe-S-rich waters, a river located in the Dabaoshan Mine area provides an ideal opportunity to study indigenous Fe- and S-metabolizing microbial communities and their roles in biogeochemical Fe and S cycling. In this work, water and sediment samples were collected from the river for physicochemical, mineralogical, and microbiological analyses. Illumina MiSeq sequencing indicated higher species richness in the sediment than in the water. Sequencing also found that Fe- and S-metabolizing bacteria were the dominant microorganisms in the heavily and moderately contaminated areas. Fe- and S-metabolizing bacteria found in the water were aerobes or facultative anaerobes, including Acidithiobacillus, Acidiphilium, Thiomonas, Gallionella, and Leptospirillum. Fe- and S-metabolizing bacteria found in the sediment belong to microaerobes, facultative anaerobes, or obligatory anaerobes, including Acidithiobacillus, Sulfobacillus, Thiomonas, Gallionella, Geobacter, Geothrix, and Clostridium. Among the dominant genera in the sediment, Geobacter and Geothrix were rarely detected in AMD-contaminated natural environments. Canonical correspondence analysis indicated that pH, S, and Fe concentration gradients were the most important factors in structuring the river microbial community. Moreover, a scheme explaining the biogeochemical Fe and S cycling is advanced in light of the Fe and S species distribution and the identified Fe- and S-metabolizing bacteria.     

基于农业生态服务价值的农业绿色GDP核算——以安塞县为例

将传统GDP绿色化,也就是“绿色GDP”是国民经济核算研究和探索的热点。从微观层面对农业生产进行绿色GDP核算,认为农业绿色GDP不仅包含传统的产品价值,还应包括农业对人类社会经济系统的生态服务价值,并以基于生态系统服务价值的“农业绿色GDP=农业常规GDP＋农业生态GDP”的公式核算了安塞县的绿色GDP。结果表明：（1）安塞县2000年的农业生产总值为29187万元,减去中间消耗为18972万元;（2）若考虑农业生态环境代价,则农业生产产值仅为6272．30万元,是农业常规GDP的33．06％,农业常规GDP背后至少隐含着66．94％的农业生态环境代价;（3）应用市场价值法、机会成本法、替代工程法、影子价格法等核算农业生态系统服务价值结果为504218．37万元,把农业生态系统服务价值作为农业系统的间接产出,则该县2000年的农业绿色GDP为510490．67万元。安塞县农业经济的获得背后至少有66．94％生态环境代价是依靠其农业生态系统的服务来提供和补偿的。