Cellular mechanisms underlying Hyperin-induced relaxation of rat basilar artery

Background and aim

Hyperin, a flavonol compound extracted from the Chinese herb Abelmoschus manihot L. Medic, is reported to exert protective actions in cerebral ischemic injury. The specific aim of the present study was to study the relaxation of Hyperin in rat isolated basilar artery and identify the underlying cellular mechanisms.

Methods

Rat isolated basilar artery segments were cannulated and perfused while being superfused with PSS solution. Vessel images were recorded by video microscopy and diameters measured. Membrane potential was recorded using glass microelectrodes to evaluate the basilar artery smooth muscle cell hyperpolarization.

Results

Perfusion of Hyperin (1 ~ 100 μM) elicited a concentration-dependent relaxation of basilar artery segments preconstricted with 0.1 μM U46619. The response was significantly inhibited by the removal of the endothelium. Hyperin also elicited marked and concentration-dependent hyperpolarization of smooth muscle cells. 30 μM nitro-L-arginine (an inhibitor of nitric oxide synthase) and indomethacin (an inhibitor of cyclooxygenase), partially inhibited Hyperin-induced relaxation and hyperpolarization leaving an attenuated, but significant, endothelium-dependent relaxation and hyperpolarization. This remaining effect was almost completely blocked by 1 mM tetraethylammonium (an inhibitor of Ca²⁺-activated K⁺ channels), or by 100 μM DL-propargylglycine, an inhibitor of cystathionine-γ-lyase (a synthase of the endogenous H₂S).

Conclusion

These findings show that Hyperin produces significant hyperpolarization in rat basilar artery smooth muscle cells and relaxation through both endothelium-dependent and endothelium-independent mechanisms. The underlying mechanisms appeared to be multi-factorial involving nitric oxide, prostacyclin, and endothelium-derived hyperpolarizing factor (EDHF). Our data further suggest that endogenous H₂S is a component of the EDHF-mediated hyperpolarization and relaxation to Hyperin.     

Degradation of monoterpenes in orange juice by gamma radiation

Single-strength orange juice was irradiated with 0, 0.89, 2.24, 4.23, and 8.71 gGy of gamma radiation at 5 degrees C and then stored at 7 degrees C for 21 days. Volatile compounds, isolated by solid-phase microextraction, were separated and identified using a gas chromatograph equipped with a mass selective detector. The majority of the volatile compounds were terpenes, and the most abundant volatile compounds were ethanol and limonene. Most volatile compounds were stable during the 21-day storage period except geranial and neral which decreased over time. Irradiation reduced the concentration of acyclic monoterpenes, such as geranial, neral, myrcene, and linalool 1 and 7 days after irradiation, but did not affect other monoterpenes, sesquiterpenes, or other volatile compounds. The reduction of acyclic monterpenes increased linearly with radiation dose, and correlated with an increase in thiobarbituric acid reactive substrates (TBARS) content. Reduction in the concentration of monoterpenes induced by irradiation was not significant 21 days after irradiation. Our results indicate that acyclic monoterpenes are sensitive to irradiation whereas most other volatile compounds are resistant.     

Fatty acid composition and squalene content of the marine microalga Schizochytrium mangrovei

Certain species of thraustochytrids are being explored as potential producer of polyunsaturated fatty acids for nutritional enrichment of food products and use as feed additives in aquaculture. The fatty acid composition and squalene content were determined in the thraustochytrid, Schizochytrium mangrovei that was newly isolated from decaying Kandelia candel leaves in Hong Kong mangrove habitat. The major fatty acid constituents identified in all three S. mangrovei strains were tetradeanoic acid (C14:0), hexadecanoic acid (C16:0), docosapentaenoic acid (C22:5 n-6, DPA) and docosahexaenoic acid (C22:6 n-3, DHA). DHA was the most predominant polyunsaturated fatty acid, and the percentage of DHA (of total fatty acids) in all these strains varied from 32.29 to 39.14%. Only slight changes were observed in fatty acid composition of the S. mangrovei strains harvested at their early (day 3) and late stationary (day 5) phases. In contrast, the cellular squalene content was affected significantly by the culture time; the largest decrease of squalene content from 0.162 mg/g to 0.035 mg/g was found in S. mangrovei FB1 as the culture aged.     

神仙鱼胚胎和仔鱼发育的初步观察

有关鱼类胚胎和仔鱼发育的研究 ,已有文献报道[1 - 5] 。神仙鱼 (Ｐｔｅｒｏｐｈｙｌｌｕｍｓｃａｌａｒｅ) ,又名燕鱼、天使鱼、小鳍帆鱼 ,原产于南美的亚马逊河 ,是重要的观赏鱼类。作者曾报道了温度和光照对神仙鱼胚胎发育的影响[6] ,本文对神仙鱼胚胎和仔鱼发育的形态学进行了观察和研究。1　材料与方法1 .1　材料实验亲鱼取自长春市某水族馆 ,配对饲养在水深 2 5ｃｍ的玻璃水族箱中 ( 4 5ｃｍ× 35ｃｍ× 30ｃｍ) ,水温2 7℃ ,每天换水 1次 ,投鲜活饵料 2次。通过自行产卵获得受精卵。1 .2　方法孵出的仔鱼移到 1 5ｃｍ× 2 5ｃｍ× 2 …     

Net Exchange of CO2 in a Mid-Latitude Forest

The eddy correlation method was used to measure the net ecosystem exchange of carbon dioxide continuously from April 1990 to December 1991 in a deciduous forest in central Massachusetts. The annual net uptake was 3.7 +/- 0.7 metric tons of carbon per hectare per year. Ecosystem respiration, calculated from the relation between nighttime exchange and soil temperature, was 7.4 metric tons of carbon per hectare per year, implying gross ecosystem production of 11.1 metric tons of carbon per hectare per year. The observed rate of accumulation of carbon reflects recovery from agricultural development in the 1800s. Carbon uptake rates were notably larger than those assumed for temperate forests in global carbon studies. Carbon storage in temperate forests can play an important role in determining future concentrations of atmospheric carbon dioxide.     

机插水稻的高产栽培技术

近年来,随着农机化发展的新问题、新任务,机插水稻的面积在不断增加,水稻种植机械化水平达到15%,为了早日实现水稻生产机械化、产业化,经过几年的实践,我们掌握了一些机插水稻的高产栽培经验.现介绍如下:     

4种农药防治棉花烟粉虱若虫药效试验

烟粉虱(BemisiatabaciGennadius)是近年来新发生的一种棉花重要害虫。它以成虫或若虫聚集在棉叶背面刺吸危害棉花,严重时引起蕾铃大量脱落,造成棉花减产。同时该虫还能大量分泌蜜露,使棉叶和棉铃污染变黑而影响棉花的光合作用,尤其是在棉铃吐絮时受到蜜露污染,会使棉纤维的     

禁食禁水对绍兴鸭生长相关激素及其基因表达的影响

 随机选取 33日龄雄性高邮鸭和绍兴鸭 ,禁食、禁水 2 4h和 4 8h后 ,采用放射免疫分析法测定血清生长激素 (GH)、胰岛素样生长因子 (IGF 1)及甲状腺素 (TH)的水平 ,用Northern杂交分析法检测垂体GH和下丘脑生长抑素 (SS)mRNA的含量。结果表明 ,禁食显著提高绍兴鸭和高邮鸭垂体GHmRNA含量与血清T4水平 ,显著降低血清T3 水平 ,而对血清GH和IGF 1水平的影响具有品种间差异。禁水对GH、IGF 1及TH的影响类似于禁食 ,但是 ,禁水对血清IGF 1和下丘脑SSmRNA没有显著影响。     

Isolation and characterization of a novel tannase from a metagenomic library

A novel gene (designated as tan410) encoding tannase was isolated from a cotton field metagenomic library by functional screening. Sequence analysis revealed that tan410 encoded a protein of 521 amino acids. SDS-PAGE and gel filtration chromatography analysis of purified tannase suggested that Tan410 was a monomeric enzyme with a molecular mass of 55 kDa. The optimum temperature and pH of Tan410 were 30 °C and 6.4. The activity was enhanced by addition of Ca(2+), Mg(2+) and Cd(2+). In addition, Tan410 was stable in the presence of 4 M NaCl. Chlorogenic acid, rosmarinic acid, ethyl ferulate, tannic acid, epicatechin gallate and epigallocathchin gallate were efficiently hydrolyzed by recombinant tannase. All of these excellent properties make Tan410 an interesting enzyme for biotechnological application.     

Isolation and identification of the DNA aptamer target to acetamiprid

As an alternative to antibodies, aptamers have a great potential as analytical tools for pesticide detection. In this work, aptamers targeting acetamiprid were selected by a specific systematic evolution of ligands by exponential enrichment (SELEX) strategy, where a single-stranded DNA (ssDNA) library was immobilized and target modification was eliminated. After 18 rounds of repeated selection, the ssDNA pool was enriched and then 14 sequences were selected and carefully identified. At last, an acetamiprid-specific aptamer with the apparent dissociation constant (K(d)) estimated to be 4.98 μM was successfully obtained. Further work is ongoing to develop an aptamer-based detection method for field determination of this pesticides in agricultural products and environmental samples.