苄基异喹啉类化合物 D20抑制钙调素激活磷酸二酯酶的研究

苄基异喹啉化合物是一类钙调素拮抗剂.对新合成的双苄基异喹啉化合物 D₂₀对钙调素依赖的磷酸二酯酶的抑制作用进行了研究,IC₅₀=5μmol/L,表明其拮抗作用大于三氟啦嗪,是强的拮抗剂.荧光分析表明,钙调素与化合物 D₂₀的结合常数为2.64(μmol/L)^-1,一个化合物 D₂₀分子与两个钙调素分子结合,并显示了结合方向性及空间位阻影响.     

Study of the Biological Activity and Phenolic Content of the Ethanol Extract of Phyllogonium viride Brid. (Phyllogoniaceae,Bryophyta)

The present study aimed to examine the phenolic content and evaluate the antimicrobial and antioxidant potential of ethanol extracts from the moss species Phyllogonium viride Brid. on the pathogenic bacteria Salmonella enterica serovar enteritidis, Staphylococcus aureus, Listeria monocytogenes and Escherichia coli, and the pathogenic fungi Candida albicans and Cryptococcus neoformans. The antimicrobial activity was determined from Minimum Inhibitory Concentration (MIC) Minimum Bactericidal Concentration (MBC) and Minimum Fungicidal Concentration (MFC). Antioxidant activity was determined by the DPPH method. Folin-Denis reagent was used for the content of total phenolics and flavonoids and HPLC-DAD for identification of phenolic compounds. The results showed that bacteriostatic and bactericidal activities occurred at concentrations ranging from 9.76 μg/mL–78.13 μg/mL among all evaluated microorganisms. These values, considering the criteria used, suggest the P. viride extract as a potent antimicrobial. For antioxidant activity, P. viride extract was considered weak. Analysis of the phenolic content showed a wide range of compounds, with Kaempferol (0.41 mg/g) being the major compound, followed by t-cinnamic acid and caffeic acid (0.17 mg/g). Although P. viride is a species of moss not yet referenced in scientific publications of biotechnological interest, it has shown promising potential for further studies and possible application as an antimicrobial of natural origin.     

Forecasting the future suitable growth areas and constructing ecological corridors for the vulnerable species Ephedra sinica in China

Ephedra sinica is a rare and vulnerable species in China, and the habitat of Ephedra sinica is seriously threatened (by climate change and human activities). Predicting the suitable growth areas and constructing ecological corridors for Ephedra sinica in China will help to protect it scientifically. Based on 306 valid distribution records and 13 selected environmental factors, the maximum entropy (MaxEnt) model was used to simulate the potential current habitat zones and future (2050 and 2070) habitat zones of Ephedra sinica under four climate change scenarios. The minimum cumulative resistance (MCR) model was applied to extract important ecological corridors of Ephedra sinica. The results indicate that: (1) Under the current environment, the total area of the suitable habitat for Ephedra sinica in China is 42.24 × 10⁵ km², mainly distributed in Northwest China and North China. (2) Suitable area increases as the RCP rises. The center of mass of the habitat zone moved northward from Shaanxi Province to Ordos City in Inner Mongolia Autonomous Region. (3) Of the 13 environmental factors selected, the primary factor was elevation (20.8 %), followed by wettest month precipitation (18.2 %) and temperature seasonality (15.2 %). (4) Built 19 ecological corridors, with a total corridor length of 430.2 km, including seven long-distance passages and 12 short-distance corridors. All corridors are far from the artificial surface, mostly near high-altitude areas. The 19 ecological corridors constructed using the MCR model will also provide considerable importance for the survival of Ephedra sinica on a longer time scale in the future.     

Two-phase species–time relationships in North American land birds

The species–time relationship (STR) is a macroecological pattern describing the increase in the observed species richness with the length of time censused. Understanding STRs is important for understanding the ecological processes underlying temporal turnover and species richness. However, accurate characterization of the STR has been hampered by the influence of sampling. I analysed STRs for 521 breeding bird survey communities. I used a model of sampling effects to demonstrate that the increase in richness was not due exclusively to sampling. I estimated the time scale at which ecological processes became dominant over sampling effects using a two‐phase model combining a sampling phase and either a power function or logarithmic ecological phase. These two‐phase models performed significantly better than sampling alone and better than simple power and logarithmic functions. Most community dynamics were dominated by ecological processes over scales <5 years. This technique provides an example of a rigorous, quantitative approach to separating sampling from ecological processes.     

Root/Shoot Allocation and Root Architecture in Seedlings: Variation among Forest Sites, Microhabitats, and Ecological Groups1

I analyzed patterns of variation in root mass allocation and root morphology among seedlings of woody species in relation to environmental factors in four Neotropical forests. Among forests, I explored the response of root traits to sites varying in water or nutrient availability. Within each forest, I explored the plastic response of species to different microhabitats: gaps and understory. Additionally, I explored evidence for life history correlation of root and shoot traits by comparing species differing in their successional group (light‐demanding [22 spp.] or shade tolerant [27 spp.]) and germination type (species with photosynthetic cotyledons or species with reserve cotyledons). At each forest site, young seedlings from 10 to 20 species were excavated. A total of 55 species was collected in understory conditions and 31 of them were also collected in gaps. From each seedling, six morphological ratios were determined. Allocation to roots was higher in forest sites with the lowest soil resources. Roots were finer and longer in the most infertile site, while roots were deeper in the site with the longest dry season. Seedling traits did not differ between germination types. Shade tolerant species allocated more to roots and developed thicker roots than light‐demanding species. Light‐demanding species showed stronger plastic responses to habitat than shade tolerant species, and species with photo‐synthetic cotyledons showed lower plasticity than species with reserve cotyledons. Overall, these results suggest that among Neotropical species, root allocation and root morphology of seedlings reflect plant adjustments to water or nutrient availability at geographic and microhabitat scales. In addition, life history specialization to light environments is suggested by differences among groups of species in their allocation to roots and in their root morphology.     

DISCOVERY OF VERTEBRATE FOSSILS AND PALEOLITHIC ARTIFACTS IN DANJIANG SUBMERGING AREA AND ITS IMPLICATIONS

IntheareatobefloodedinthesecondengineeringstagefortheDanjiangreservoir,wediscovered16vertebratefossillocalitiesand52Paleolithicsitesin1994,andcollected603artifactsandmanyfossils.Ofthel6new1yfoundvertebratefossillocalities,threearereptilesitesrepresentedbydinosaureggsandlimbbones,andl3producemamma1s,including4Pale0gene,2Ne0geneand7Quaternarysites'ThemammalianlocalitiesareofPale0cene,Eocene,EarlyMiocene,andPli0ceneorEarlyPleistocene,MiddleandIntePleistocene,respectively.Theyfillinsomestrat…     

Ecological compensation of the impacts of a road. Preliminary method for the A50 road link (Eindhoven-Oss, The Netherlands)

After years of efforts to avoid or reduce the impact of infrastructure projects on nature, the principle of ecological compensation has been incorporated in Dutch governmental policy. Ecological compensation aims to recover those ecological functions and natural values that still remain affected after maximum effort has been made to reduce the impact of the intervention (mitigation). The accepted aim of current policy is thus no-net-loss of area and quality by means of mitigative and compensatory measures. As part of the planning process for construction of a stretch of road in The Netherlands, viz., the A50 road link in the province of North Brabant, a Nature Compensation Plan (NCP) was required to be drawn up. This work has recently been completed by the Regional Directorate of Public Works and Water Management, the initiator of the intervention. The NCP, initially presented as a Draft Plan, was drawn up by the Regional Directorate using a preliminary method designed by the Centre of Environmental Science of Leiden University for deriving compensatory measures. After an opportunity for public comment, the Draft Plan was revised to form a Final NCP. This article describes, firstly, the preliminary method for deriving ecological compensatory measures. The method starts by quantifying the effects of habitat loss, habitat disturbance (by changes in noise emissions, in the water table and in outdoor recreational patterns), barrier action and fauna casualties. Following mitigation of impacts on nature, compensation for non-mitigable effects focuses successively on area size, derived from the impacts on breeding birds, and on area quality, derived from the habitat requirements of the vegetation and fauna groups affected by the road. Guidelines for identifying appropriate locations for compensation are also formulated. Secondly, the compensation method is applied to calculate the mitigative and compensatory measures for the A50 trajectory between Eindhoven and Oss. Thirdly, two comparisons are made: the Draft NCP is compared with the results of the preliminary method, and the Draft and the Final NCP are compared with one another in order to identify the role of the interest groups that played a major role in commenting on the Draft Plan. Finally, realization of the compensatory measures and development of the preliminary method itself are discussed. On the basis of the experience with the A50 case study, a more robust compensation method for road projects is to be developed.     

超氧化物歧化酶模拟化合物的生物活性研究

根据天然超氧化物歧化酶(SOD)活性部位结构合成了含苯并咪唑的5种配体及其32种分别含Cu（Ⅱ）、Fe（Ⅲ）、Mn（Ⅱ）、Co（Ⅱ）的模拟化合物.经光谱、电化学测试证明这些化合物具有拟S3D活性,其50％抑制率浓度（IC50）为10-6～10-8mol·L-1,催化超氧离子自由基（O-·2）歧化的反应速率常数kq为106～108mol-1·L·s-1.同时观察到几种模拟化合物有抗肿瘤活性或增强水稻抗寒性.     

蛋白质中原子与基团的可及性的一种新计算方法及其应用

实现了一种新的蛋白质中原子层次可及面积的计算方法－Ｍｏｎｔｅ－Ｃａｒｌｏ模拟方法。计算了溶菌酶各个原子与功能基团的可及性,并应用于蛋白质结构和功能的研究中。使得对蛋白质性能的预测更准确,提供了一种对蛋白质结构和功能研究的新思路。