Molecular characterization of melanin-concentrating hormone (MCH) in <Emphasis Type="Italic">Schizothorax prenanti</Emphasis>: cloning,tissue distribution and role in food intake regulation

Melanin-concentrating hormone (MCH) is a crucial neuropeptide involved in various biological functions in both mammals and fish. In this study, the full-length MCH cDNA was obtained from Schizothorax prenanti by rapid amplification of cDNA ends polymerase chain reaction. The full-length MCH cDNA contained 589 nucleotides including an open reading frame of 375 nucleotides encoding 256 amino acids. MCH mRNA was highly expressed in the brain by real-time quantitative PCR analysis. Within the brain, expression of MCH mRNA was preponderantly detected in the hypothalamus. In addition, the MCH mRNA expression in the S. prenanti hypothalamus of fed group was significantly decreased compared with the fasted group at 1 and 3 h post-feeding, respectively. Furthermore, the MCH gene expression presented significant increase in the hypothalamus of fasted group compared with the fed group during long-term fasting. After re-feeding, there was a dramatic decrease in MCH mRNA expression in the hypothalamus of S. prenanti. The results indicate that the expression of MCH is affected by feeding status. Taken together, our results suggest that MCH may be involved in food intake regulation in S. prenanti.     

山楂引种试验报告

根据山楂的生物学特性,通过在不同立地条件下进行引种栽培试验,总结出山楂在当地栽培成功的措施和经验,为六盘山地区退耕还林后续产业的培育开辟途径。     

鸡眼草和美丽胡枝子对贫瘠土壤的生态适应性比较

采用来自浙江省金衢盆地红壤坡耕地和严重侵蚀退化瘠薄地带的2种土壤,对鸡眼草和美丽胡枝子2种豆科植物进行盆栽实验,比较研究2种豆科植物对贫瘠土壤的适应性.结果表明,在贫瘠土壤条件下,鸡眼草的地上干重,叶绿素含量、浓度氮、浓度磷均极显著高于美丽胡枝子;在正常土壤条件下除浓度磷外,其它理化性状鸡眼草也显著高于美丽胡枝子;在2种土壤条件下,鸡眼草叶绿素含量差异不显著,而美丽胡枝子差异极显著.说明,在贫瘠土壤中鸡眼草较美丽胡枝子具有更强的营养吸收能力,更耐贫瘠.     

system modeling and simulation of wind turbines

Wind turbines operate in harsh environment with transient and variable working conditions. As a result, wind turbines are complicated, nonlinear, uncertain systems. Modeling and analysis of these systems are crucial to their design. Based on MATLAB, a new dynamic simulation model of a stalled wind turbine was presented. The blade element momentum theory and the state space method were programmed into MATLAB/SIMULINK to calculate wind turbine aerodynamic performance. The generator was also modeled in MATLAB/SIMULINK, taking the coupling between the generator and the rotor speed into consideration. Based on the proposed MATLAB model, an analysis of a 600 kW wind turbine was carried out. The calculation values were compared with the measured data. The results indicate the correctness of the proposed MATLAB model. The simulation model can be applied to optimize design and control of stalled wind turbines.     

Plant functional types rather than climate or soil determine leaf traits in the forest biomes of eastern China

Nitrogen (N) has great ecological importance, but the biogeographic pattern across forest biomes in China has only recently been explored. Here we conducted a systematic census of leaf C and N following the same protocol to explore the variations of leaf traits, and their possible responses to plant functional types (PFTs) and environmental factors. Results showed that leaf traits varied substantially across biomes, and the relationships of PFTs to climatic factors were stronger than those of PFTs versus soil nutrient proxies, indicating that plant species composition might be a better predictor of plant species distribution with climate than leaf traits. Soil nutrient proxies explained more variation of leaf traits than climate, which demonstrates that leaf traits reflect important aspects of plant responses to soil nutrients. Importantly, partial general linear models analyses found that PFTs showed the greatest direct influence for leaf traits, and climate and soil affected leaf traits mainly through the change in plant species composition rather than having direct impacts. Hence, we concluded that leaf traits were largely controlled by PFTs rather than climate or soil at the biome scale. The results favored the species composition hypothesis, indicating that leaf nutrient concentration is mainly determined by PFTs.     

基于PCR的两步法丝状真菌基因敲除方法

基因敲除是研究真菌基因功能的重要方法之一,目前,丝状真菌敲除多采用基因两侧的同源臂对基因组的靶标进行同源替换,然后采用抗生素对转化子进行筛选,但这存在着筛选效率低、假阳性率高、操作复杂等问题。本研究以稻瘟菌为研究对象,采取以下步骤对此进行优化:1)构建HPH-GFP(潮霉素-绿色荧光蛋白)融合表达载体; 2)分别用带有接头序列的引物克隆待敲除基因上、下游片段; 3)克隆上、下游片段与HPH-GFP组成嵌合体片段; 4)嵌合体片段转化真菌原生质体; 5)对敲除突变体进行筛选。结果表明,该法操作简便、高效,除了用潮霉素HPH作为筛选标记外,还可用GFP作为荧光筛选标记,极大提高了筛选效率,可用作丝状真菌基因功能研究。     

In Vitro and In Vivo Anti-Inflammatory Effects of Sulfated Polysaccharides Isolated from the Edible Brown Seaweed,Sargassum fulvellum

In the present study, the in vitro and in vivo anti-inflammatory effects of the sulfated polysaccharides isolated from Sargassum fulvellum (SFPS) were evaluated in lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophages and zebrafish. The results indicated that SFPS improved the viability of LPS-stimulated RAW 264.7 macrophages from 80.02 to 86.80, 90.09, and 94.62% at the concentration of 25, 50, and 100 µg/mL, respectively. Also, SFPS remarkably and concentration-dependently decreased the production levels of inflammatory molecules including nitric oxide (NO), tumor necrosis factor-alpha, prostaglandin E₂, interleukin-1 beta, and interleukin-6 in LPS-treated RAW 264.7 macrophages. In addition, SFPS significantly inhibited the expression levels of cyclooxygenase-2 and inducible nitric oxide synthase in LPS-treated RAW 264.7 macrophages. Furthermore, the in vivo test results indicated that SFPS improved the survival rate of LPS-treated zebrafish from 53.33 to 56.67, 60.00, and 70.00% at the concentration of 25, 50, and 100 µg/mL, respectively. In addition, SFPS effectively reduced cell death, reactive oxygen species, and NO levels in LPS-stimulated zebrafish. Taken together, these results suggested that SFPS possesses strong in vitro and in vivo anti-inflammatory activities, and could be used as an ingredient to develop anti-inflammatory agents in the functional food and pharmaceutical industries.     

对国有林场管理体制和经营机制改革问题的思考

分析了国有林场改革试点工作中所面临的重点难点问题,并从搞活经营机制、多渠道妥善安置富余职工、解决历史欠账、优化资源配置、整合生产要素等方面提出了发展建议。