诃子水提物抑菌活性成分稳定性

以番茄晚疫病原菌为供试菌,研究了诃子水提物活性成分的稳定性,为防治番茄病害、提高产量提供一定的帮助,同时为开发新型植物源农药提供理论支持。结果表明:诃子水提物具有很好的抑菌作用,其最小抑菌浓度为3.9 mg·mL-1。诃子水提物经过酸、碱处理后其在酸性条件下抑菌圈直径较大,抑菌活性较好,经过碱处理后水提物的抑菌圈直径明显减小,抑菌活性显著下降;水提物对温度、紫外照射具有良好的稳定性;蔗糖浓度为2%时,抑菌圈直径最大,抑菌效果最好,之后随着蔗糖浓度的增高,抑菌圈直径减小,抑菌活性降低;当水提物中加入Ca2+、Mg2+、Fe3+3种金属离子时抑菌圈直径增大,抗菌能力显著提高。     

一类具有饱和发生率的虫媒传染病模型研究

考虑虫媒传染病具有潜伏期的特征,研究了一类具有饱和发生率的时滞传染病模型的动力学行为,确定了疾病是否流行的阈值R_0.当R_01时,无病平衡点全局渐近稳定,疾病将最终灭绝;当R_01时,唯一地方病平衡点条件稳定,系统会产生Hopf分支.     

茶红素分离及稳定性研究

采用茶汤有机试剂萃取分离,并分别经过反相C_(18)柱层析纯化,制备出乙酸乙酯层、正丁醇层和酸性正丁醇层三部分茶红素。根据紫外可见光波扫描计算出色价,并研究了茶红素在不同条件下的稳定性。结果表明,30%、50%和70%甲醇梯度洗脱,纯化后3类茶红素液相检测发现无咖啡碱和茶黄素,仅有少量儿茶素杂质。纯化后色素色价分别为乙酸乙酯层128.04,正丁醇层91.04,酸性正丁醇层76.16。遮光处理,p H=3酸性条件,45℃以下贮藏,有利于茶红素的稳定性。     

植物碱基错配修复系统中Muts蛋白家族研究进展

DNA错配修复(mismatch repair,MMR)是DNA损伤修复的一个重要途径,主要用于细胞中DNA合成和遗传重组时发生损伤过程中出现的单个或少数碱基的缺失、插入以及错配的修复,它对维持基因组稳定性和DNA复制保真度至关重要。原核生物和真核生物中都有非常保守的MMR系统。在人体DNA修复系统的研究中,发现癌症的发生与Muts蛋白家族功能缺陷密切相关。类似的在拟南芥和水稻中功能缺陷的Muts蛋白家族(同源蛋白Muts homolog,MSH)会产生增变基因表型,这将为植物的基因功能分析和育种利用奠定基础。基于此,本文综述了近年来有关植物DNA错配修复及相关基因功能的研究进展,特别是植物MMR功能缺陷导致基因突变和微卫星不稳定造成的性状畸形进行了描述,对Muts蛋白家族各个亚基功能做了分类说明,并对植物中如何利用MSH产生的增变基因突变和如何利用突变育种研究进行了展望。     

Oxidative Stability of Common Kilka (Clupeonella cultriventris caspia) Oil Supplemented with Microwave Extracted Ghure (Unripe Grape) Marc Extract

The objective of this study was to evaluate the effect of microwave extracted Ghure (unripe grape) marc extract on common kilka (Clupeonella cultriventris caspia) oil oxidation during accelerated storage. The antioxidant activity of Ghure marc extract was compared with those of α-tocopherol and BHT. The Ghure marc extract significantly reduced the peroxide and p-anisidine value of kilka oil. Even though the effect of Ghure marc extract on reducing the oxidation of kilka oil was similar to the effect of BHT, it was functionally more effective than α-tocopherol. Generally, Ghure marc extract could be considered as a potential source of natural antioxidants, with inexpensive costs, for improving the oxidative stability of kilka oil.

Abbreviations: AA, Antioxidant activity; AOP, Antioxidant power; AV, p-Anisidine value; CUPRAC, Cupric ion reducing antioxidant capacity; DHA, Docosahexaenoic acid; EPA, Eicosapentaenoic acid; FIC, Ferrous ion chelating; GME, Ghure marc extract; FRAP, Ferrous ion reducing antioxidant power; KO, Kilka oil; IP, Induction period; MAE, Microwave-assisted extraction; MUFA, Monounsaturated fatty acid; PUFA, Polyunsaturated fatty acid; PV, peroxide value; PF, Protection factor; RSA, Radical scavenging activity; SFA, Saturated fatty acids; TFC, Total flavonoid content; TPC, total phenolic content TV, totox value.     

类人机器人全能运动的稳定性研究

类人机器人全能运动包括不同粗糙平面上的快速行走、越障、踢球、格斗等,稳定性是上述运动的关键环节。本文从分析机器人关节角与零力矩点（ZMP）的关系入手,研究提高机器人运动稳定性的新方法。具体步骤是先粗调校正机器人姿态,然后确定各关节角度,得到保证稳定运动的关节角范围。最后依托韩国GP型机器人进行测试,结果表明了所提出方法的有效性。     

Strong functional stability of soil microbial communities under semiarid Mediterranean conditions and subjected to long-term shifts in baseline precipitation

We investigated the effect of soil microclimate on the structure and functioning of soil microbial communities in a Mediterranean Holm-oak forest subjected to 10 years of partial rain exclusion manipulations, simulating average drought conditions expected in Mediterranean areas for the following decades. We applied a high throughput DNA pyrosequencing technique coupled to parallel measurements of microbial respiration (R_H) and temperature sensitivity of microbial respiration (Q₁₀). Some consistent changes in the structure of bacterial communities suggest a slow process of community shifts parallel to the trend towards oligotrophy in response to long-term droughts. However, the structure of bacterial communities was mainly determined by short-term environmental fluctuations associated with sampling date (winter, spring and summer) rather than long-term (10 years) shifts in baseline precipitation. Moreover, long-term drought did not exert any chronic effect on the functioning of soil microbial communities (R_H and Q₁₀), emphasizing the functional stability of these communities to this long-term but mild shifts in water availability. We hypothesize that the particular conditions of the Mediterranean climate with strong seasonal shifts in both temperature and soil water availability but also characterized by very extreme environmental conditions during summer, was acting as a strong force in community assembling, selecting phenotypes adapted to the semiarid conditions characterizing Mediterranean ecosystems. Relations of climate with the phylogenetic structure and overall diversity of the communities as well as the distribution of the individual responses of different lineages (genera) to climate confirmed our hypotheses, evidencing communities dominated by thermotolerant and drought-tolerant phenotypes.     

Stability analysis of seven agronomic traits for soybean [(Glycine max (L.) Merr.] Tokachi nagaha and its derived cultivars using the AMMI model

The stabilities of seven agronomic traits were analyzed and the general stabilities of soybean [Glycine max (L.) Merr.] accessions were evaluated based on the additive main effects and multiplicative interactions (AMMI) model using the founder parent Tokachi nagaha and 137 of its derived cultivars as materials. The objective was to provide a theoretical basis for effectively using germplasm in soybean breeding and production. Analysis of variance (ANOVA) showed that genotype, environment, and genotype by environment interactions were significantly different for each trait. The first three interaction principal components axes (IPCA) were highly significant, accounting for 61.28–70.00% of the total variation. The stability differed for the different traits. 50 cultivars with high general stabilities were identified. The general stability of Tokachi nagaha was moderate, as the stability coefficients (D_i) of its seven traits were relatively high; this must be considered by breeders using this cultivar as a breeding parent. There were significant positive correlations between the phenotypic values and their own D_i values for number of branches per plant, number of pods per plant, number of seeds per plant, and seed weight per plant. This would lead to the expectation that the phenotypic stability would be lower when a cultivar had more branches, pods, seeds, and high per plant yields. Thus, it appears difficult to breed cultivars that simultaneously have high yields and high stability.     

三类病毒感染下的手足口病模型的动力学分析

建立了CA16病毒、 EV71病毒及其他病毒株感染下周期性发病的手足口病模型.得到了模型的基本再生数并用它证明了模型无病平衡点的全局渐近稳定性.另外,分析了单一病毒株周期解的稳定性.最后,发现基本再生数最大的病毒株会持续生存下来,其他两种病毒株会被竞争排斥掉.     

全银杏粉饮料配方的模糊数学法优化及其稳定性研究

为解决泰州大佛指银杏加工季节限制，获得一款口感宜人、稳定性良好的保健型饮料，以全银杏粉为主要原料，通过模糊数学法结合正交试验优化全银杏粉饮料的最佳配方，采用功效系数法结合正交试验优化全银杏粉饮料稳定剂的最佳复配比，以均质压力和均质温度对全银杏粉饮料稳定性的影响确定最佳均质条件。结果表明，全银杏粉饮料的最佳配方为：全银杏粉初汁添加量80%，低聚果糖添加量10%，柠檬酸添加量0.10%，蜂蜜添加量0.10%；稳定剂最佳复配比为：微晶纤维素（MCC）0.15%，卡拉胶0.20%，海藻酸丙二醇酯（PGA）0.20%；最佳均质条件为：均质压力40 MPa，均质温度60 ℃。