Procyanidin fractions from pine (Pinus pinaster) bark: radical scavenging power in solution, antioxidant activity in emulsion, and antiproliferative effect in melanoma cells

Pine (Pinus pinaster) bark is a rich source of procyanidin oligomers. From a total polyphenolic extract, we have generated fractions of different procyanidin composition. The mixtures, devoid of gallate esters, were active as free radical scavengers against ABTS(*+), DPPH, and HNTTM. Pine bark fractions were tested for antioxidant activity in solution (hydrogen donation and electron transfer) and emulsion (inhibition of lipid peroxidation) and compared with their galloylated counterparts from grape origin. While galloylation clearly influenced the free radical scavenging efficiency in solution, it did not seem to play a determinant role in protection against lipid peroxidation in emulsion. The fractions were very mild inhibitors of cell proliferation. Because gallate esters appear to interfere with crucial cell functions, gallate free pine procyanidins may be the innocuous chemopreventative agents of choice for many applications in food and skin protection.     

Nitrogen Release from Slow-Release Fertilizers in Soils with Different Microbial Activities

Soil microbial activity is recognized as an important factor affecting nitrogen (N) release from slow-release fertilizers. However,studies on the effect of size and activity of soil microflora on fertilizer degradation have provided contrasting results. To date, no clear relationships exist between soil microbial activity and the release of N from slow-release fertilizers. Hence, the aim of this study was to better understand such relationships by determining the release of N from three slow-release fertilizers in soils with different microbial activities. Soils were amended with urea-formaldehyde (UF), isobutylidene diurea (IBDU), and crotonylidene diurea (CDU). Urea, a soluble fertilizer, was used as the control. Fertilized soil samples were placed in a leaching system, and the release of N was determined by measuring ammonium-N and nitrate-N concentrations in leachates during 90 d of incubation. Non-linear regression was used to fit N leaching rate to a first-order model. In all the treated soils, N was released in the order: urea (89%–100%) IBDU (59%–94%) UF (46%–73%) CDU (44%–56%). At the end of incubation, N released from CDU did not differ (P 0.05) among soils. On the contrary, UF and IBDU released significantly lower (P 0.05) amounts of N in the soil with higher microbial activity and lower pH.The rate constant (K_0) for UF was lower (P 0.05) in the soil with lower pH. Taken together, our results indicated that soil microbial size and microbial activity had a marginal effect on fertilizer mineralization.     

畜禽粪便堆肥腐熟度评价指标体系研究

以牛粪和猪粪两种畜禽粪便分别与秸秆混合堆肥.全面考察了堆肥过程中与腐熟度有关的理化指标和生物指标变化.结果表明.在3个月的堆肥熟化试验考察期内,堆肥初期堆体升温迅速,50℃上高温持续时间累计超过15 d;物料pH值先升后降,60d后稳定在8.0左右;含水率和C/N持续下降,C/N 60 d后接近20;氨氮含量呈先升后降趋势,胡敏酸和富里酸比值则先降后升;Solvita腐熟等级、种子发芽势和根系建成指标不断升高,而作物生长指标则无显著变化.由腐熟度指标相关性分析表明,最能体现堆肥腐熟程度的Solvita腐熟等级与C/N、种子发芽势、根系建成指标呈高度相关,与含水率和腐殖酸呈低度相关.据此,结合常规温度指标建立了堆肥腐熟度评价指标体系.用于科学指导农牧业废弃物堆肥质量控制.     

热塑淀粉Mater-Bi可生物降解地膜的适用性与降解性能研究

通过霉菌侵蚀法、田间考察法和受控掩埋试验法,对Mater-Bi可生物降解地膜在上海郊区的适用性及其生物降解性能进行了研究.结果表明,Mater-Bi可生物降解地膜由于其高达90%的淀粉含量,能够被霉菌等微生物作为碳源所利用,仅需数天,霉菌菌落即可在该膜表面旺盛生长.在上海崇明岛的气候条件下,Mater-Bi可生物降解地膜的诱导期为60～120d,在田间生产中具有良好的适用性,能够满足上海郊区作物生产的需要.Mater-Bi可生物降解地膜能够被崇明岛当地农田土壤中的微生物迅速降解,在土壤中埋藏90d后.失重率为58.6%.其降解速度在10～20cm耕作层土壤中的最快,90d后失重率即高达84.2%.因此种植季结束后,可生物降解地膜不需要人工或机械捡拾残膜,只需翻耕入土壤即可,最佳翻耕深度为10～20cm.     

Protective effect of structurally diverse grape procyanidin fractions against UV-induced cell damage and death

UV radiation leads to the generation of reactive oxygen species (ROS). These molecules exert a variety of harmful effects by altering key cellular functions and may result in cell death. Several studies have demonstrated that human skin can be protected against UV radiation by using plant-derived antioxidants. Here we evaluated the in vitro capacity of several antioxidant polyphenolic fractions from grape, which differ in their degree of polymerization and percentage of galloylation, to protect HaCaT human keratinocytes against UV-induced oxidative damage. These fractions inhibited both basal and UVB- or UVA-induced intracellular ROS generation in this cell line. Consequently, the same fractions inhibited p38 and JNK1/2 activation induced by UVB or UVA radiation. The highest protective effect was for fractions rich in procyanidin oligomers and gallate esters. These encouraging in vitro results support further research and should be taken into consideration into the clinical pharmacology of plant-derived polyphenolic extracts as novel agents for skin photoprotection.     

A combined analysis based on microbial communities and volatile organic compounds as a tool to study soil quality in an urban environment

<正>Dear Editor,Soil quality is defined as“the capacity of a soil to function,within ecosystem and land use boundaries,to sustain productivity,maintain environmental quality,and promote plant and animal health”(Doran and Parkin 1994).In this context,soil functionality is fundamental to the biosphere and is highly dependent on the associated microbiota.Soil microorganisms are relevant for terrestrial ecosystem functioning,and understanding the functional changes of the biological community i...     

未来十年蛋氨酸全球展望（二）

蛋氨酸在家禽生产过程中极为重要,因此家禽业也成为了决定蛋氨酸未来的关键性行业。在未来家禽业特别是肉鸡生产方面,虽然鸡肉产量的增长率正在下降,但其绝对增量仍很稳定,因此与其他肉类相比,鸡肉仍具有很强的竞争力。     

Punicalagin and catechins contain polyphenolic substructures that influence cell viability and can be monitored by radical chemosensors sensitive to electron transfer

Plant polyphenols may be free radical scavengers or generators, depending on their nature and concentration. This dual effect, mediated by electron transfer reactions, may contribute to their influence on cell viability. This study used two stable radicals (tris(2,3,5,6-tetrachloro-4-nitrophenyl)methyl (TNPTM) and tris(2,4,6-trichloro-3,5-dinitrophenyl)methyl (HNTTM)) sensitive only to electron transfer reduction reactions to monitor the redox properties of polyphenols (punicalagin and catechins) that contain phenolic hydroxyls with different reducing capacities. The use of the two radicals reveals that punicalagin's substructures consisting of gallate esters linked together by carbon-carbon (C-C) bonds are more reactive than simple gallates and less reactive than the pyrogallol moiety of green tea catechins. The most reactive hydroxyls, detected by TNPTM, are present in the compounds that affect HT-29 cell viability the most. TNPTM reacts with C-C-linked gallates and pyrogallol and provides a convenient way to detect potentially beneficial polyphenols from natural sources.     

瑞利波泄漏模式的模拟研究

瑞利导波相速度频散曲线有时会出现截止或截断现象，此时必须考虑泄漏模式波的存在，如何快速求取泄漏模式波的相速度大小是研究的核心问题．采用添加附加层的方法，使瑞利波实频散方程求根的范围包含所有的层速度区域，从而可用Abo—zena，Menke和Bixing Zhang等学者研究过的传递矩阵理论，利用二分法求解相速度大小，即用导波来模拟计算泄漏模式波相速度大小．从模拟计算结果来看，附加层法不仅能模拟出原模型的实数导波，而且还能计算出泄漏模式波的变化．由此可见，用附加层法来计算瑞利波的泄漏模式是可行的；同时，若将该方法应用于瑞利波勘探的反演，它不会增加未知数的个数。