Discovery of Novel Diterpenoids from Sinularia arborea     

Kuan-Hua Chen  Chang-Feng Dai  Tsong-Long Hwang  Chun-Yu Chen  Jan-Jung Li  Jih-Jung Chen  Yang-Chang Wu  Jyh-Horng Sheu  Wei-Hsien Wang  Ping-Jyun Sung 《Marine drugs》2014,12(1):385-393

Two novel diterpenoids, sinularbols A (1) and B (2), which were found to possess a new carbon skeleton were isolated from the soft coral Sinularia arborea. The structures of compounds 1 and 2 were elucidated by spectroscopic methods and 2 displayed a moderately inhibitory effect on the generation of superoxide anion by human neutrophils.  相似文献   

Discovery of new eunicellins from an Indonesian octocoral Cladiella sp     

Chen YH  Tai CY  Su YD  Chang YC  Lu MC  Weng CF  Su JH  Hwang TL  Wu YC  Sung PJ 《Marine drugs》2011,9(6):934-943

Two new 11-hydroxyeunicellin diterpenoids, cladieunicellin F (1) and (-)-solenopodin C (2), were isolated from an Indonesian octocoral Cladiella sp. The structures of eunicellins 1 and 2 were established by spectroscopic methods, and eunicellin 2 was found to be an enantiomer of the known eunicellin solenopodin C (3). Eunicellin 2 displayed inhibitory effects on the generation of superoxide anion and the release of elastase by human neutrophils. The previously reported structures of two eunicellin-based compounds, cladielloides A and B, are corrected in this study.  相似文献   

Effect of dietary potassium and anionic salts on acid–base and mineral status in periparturient cows     

M. Rérat  P. Schlegel 《Journal of animal physiology and animal nutrition》2014,98(3):458-466

Dry cow diets based on grassland forage from intensive production contain high amounts of K and could be responsible for a reduced ability to maintain Ca homoeostasis. The aim of this study was to determine whether a moderate anionic salt supplementation to a forage‐based pre‐calving diet with varying native K content affects the mineral and acid–base status in transition cows. Twenty‐four dry and pregnant Holstein cows, without antecedent episodes of clinical hypocalcemia, were assigned to two diets during the last 4 weeks before estimated calving date. Twelve cows were fed a hay‐based diet low in K (18 g K/kg DM), and 12, a hay‐based diet high in K (35 g K/kg DM). Within each diet, six cows received anionic salts during the last 2 weeks before the estimated calving day. After calving, all cows received the high K diet ad libitum. Blood samples were taken daily from day 11 pre‐partum to day 5 post‐partum. Urine samples were taken on days 7 and 2 pre‐partum and on day 2 post‐partum. The anionic salt did not alter feed intake during the pre‐partum period. Serum Ca was not influenced by the dietary treatments. Feeding pre‐partum diets with low K concentrations induced a reduced metabolic alkalotic charge, as indicated by reduced pre‐partum urinary base–acid quotient. Transition cows fed the low K diet including anionic salts induced a mild metabolic acidosis before calving, as indicated by higher urinary Ca, lower urinary pH and net acid–base excretion. Although serum Ca during the post‐partum period was not affected by dietary treatment, feeding a low K diet moderately supplemented with anionic salts to reach a dietary cation–anion difference close to zero permitted to obtain a metabolic response in periparturient cows without altering the dry matter intake.  相似文献   

Ion Exchanging-Spectrophotometric Determination of Micro Amounts Gallium with Butylrhodamine B in Lead-Zinc Mineral I     

LONG Yan hui  DAI Xing long 《保鲜与加工》2002,(9):16-19

This paper developed a spectrophotometric determination of micro amounts of Gallium with butylrhodamineB in lead-zinc mineral. Large amounts of interfering ions Zn 2+ ?Pb 2+ ?Al 3+ ?Ca 2+ can be separated by anion exchange resin. High bond ions can be eliminated by using 6 mol/L hydrochloric acid-ascorbic acid.Gallium remained in column can be eluted by 0.5 mol/L hydrochloric acid. In the presence of acidic and Titanium chloride, by means of benzene extracting,determined the ultraviolet-red complex combined GaCl - 4 with butylrhodamineB.The method has been applied to determination of micro amounts of Gallium in lead-zinc mineral satisfactorily.  相似文献   

植物体中的阴离子通道     

尤江峰  郑绍建 《植物营养与肥料学报》2006,12(2):266-272

阴离子通道在调节植物生长发育,营养吸收及适应干旱、盐胁迫、铝毒和缺磷胁迫等不良环境中起重要作用。本文总结介绍了它们在植物体内的广泛定位,细胞功能,基本性质和介入的可能的信号传导过程,使研究者更加深刻地认识植物体中的阴离子通道,以便对各种类型阴离子通道的进一步研究。另外,本文还介绍了保卫细胞膜上S-型阴离子通道的可能蛋白质组成和小麦根尖编码铝诱导苹果酸分泌转运体的可能基因,旨在探讨阴离子通道分子生物学基础的研究方法。  相似文献   

Exudation of organic anions by roots of cabbage,carrot, and potato as influenced by environmental factors and plant age   总被引：1，自引：0，他引：1  

Nigussie Dechassa  Manfred K. Schenk 《植物养料与土壤学杂志》2004,167(5):623-629

A previous study demonstrated that cabbage was P efficient compared to carrot and potato. However, calculating plant P uptake by a mechanistic simulation model based on P transport by diffusion and mass flow, P uptake of roots according to the Michaelis‐Menten kinetics, and morphological root characteristics including root hairs, revealed that these parameters could explain only 2/5 of the total P uptake of cabbage, but 4/5 of that of carrot and potato (Dechassa et al., 2003). Therefore, it was hypothesized that a higher root exudation of organic anions may enhance P mobilization and hence P uptake of cabbage. The objective of this research was to determine root exudation of organic anions by the three species, and to investigate the influence of plant age and dark/light period on organic‐anion exudation by cabbage. Experiments were conducted in a growth chamber in nutrient solution with or without P. Organic anions were determined in root exudates and in root tissue. With cabbage and potato, P deficiency induced exudation of citrate and succinate, respectively. Citrate‐exudation rate of P‐deficient cabbage plants was correlated with accumulation of citrate in root tissue. In contrast, high succinate‐exudation rates in potato were not correlated with an increased concentration in root tissue. For carrot, no change was observed in the exudation of any of the organic anions in response to P deficiency. The results also showed that succinate‐ and citrate‐exudation rates of cabbage roots increased with increased plant age. There was also a significant increase in exudation rates of organic anions of cabbage roots during the light period of the day. It was concluded that cabbage had the ability to exude large amounts of citrate in response to P deficiency by which it can additionally enhance its P‐uptake efficiency, whereas carrot and potato showed little evidence of possessing such a mechanism.  相似文献   

盐酸制备新型阴离子添加剂产品最佳工艺的研究     

张思维  李长皓  李旦  周凌云  王加启  雒秋江 《中国畜牧兽医》2007,34(1):27-30

本试验根据正交试验L9(34)设计，使用常用蛋白饲料作为载体，盐酸为阴离子源，以最终阴阳离子差（DCAD）值为主要评价指标，同时考虑粗蛋白质含量变化情况，优选新型阴离子添加剂的制备工艺。试验结果表明：在实际生产条件下，以DDGS作为载体，盐酸与水的混合比例为1∶1，采用自然干燥的方法，酸液与载体混合比例为1∶1.5，成品为颗粒状，无不良气味，DCAD值为-2313.69 meq/kg DM，粗蛋白质含量27.28%。  相似文献   

检测乳管细胞中黄色体产生O_2~-速率的研究   总被引：1，自引：0，他引：1  

校现周  蔡磊 《热带作物学报》2001,(1)

采用羟胺氧化法对橡胶树胶乳中黄色体产生Ｏ２－的速率进行研究，结果表明反应体系 中需加入一定浓度的Ｃａ２＋，并且也要控制适宜的温度与ｐＨ值。研究结果还表明，部分死皮 树胶乳中黄色体产生Ｏ２－的速度大于正常树。  相似文献   

NO诱导IAA和O2.-积累于侧根尖端促进水稻侧根生长     

朱雄梅  蔡慧楠  邓舒琪  刘瑞琪  林佩锦  莫亿伟  金晨钟  郞双怡  黄悦 《农业现代化研究》2022,43(3):513-521

为了探讨NO和超氧阴离子对水稻种子根侧根生长的影响,以DR5-GUS标记IAA的转基因水稻为材料,种子催芽萌发后,用含有不同浓度的NO供体、NO合成酶抑制剂和清除剂溶液来培养萌发3 d的水稻幼苗,在培养的第3 d和第5 d分别测量初生根长度和初生根上侧根数量,并通过DAF-2DA对NO、GUS对IAA和NBT对超氧阴离子（O₂·^-）染色后,在显微镜下观察NO、IAA和O₂·^-在侧根的定位,分析与NO合成相关的基因表达。结果表明,NO和IAA主要分布在根中柱的维管束部分以及侧根起始形成处和侧根根尖,O₂·^-只极性分布在侧根起始部位和侧根根尖。当NO合成受到抑制或清除时,NO、IAA和O₂·^-在侧根的积累量明显减少,侧根数量及初生根长度也均显著下降。荧光定量PCR分析发现,外源的NO供体SNP处理均能显著诱导水稻OsNIA1和OsNIA2基因表达,而NO合成酶抑制剂处理则抑制OsNIA1和OsNIA2基因表达。基于我...  相似文献   

儿茶素抗氧化作用的协同增效效应   总被引：9，自引：3，他引：9  

沈生荣  杨法军 《茶叶科学》1993,13(2):141-146

用电子自旋共振(ESR)和化学发光技术,研究了(-)-EGCG、(-)-ECG、(-)-EC、(-)-EGC 4种儿茶素及其不同组合,对超氧阴离子自由基(O(?))的清除作用。结果表明,单一儿茶素以(-)-EGCG 的清除能力最强,其纳摩尔清除率为316.3,其次为(-)-ECG,纳摩尔清除率为262.9;两两不同组合对O(?)的清除率以(-)-EGCG+(-)-ECG 效果最佳,比各自单独存在时要增效,三三组合时以(-)-EGCG+(-)-ECG+(-)-EC 组合效果最佳,增效效果明显,且强于两两组合。这些组合的增效效果与体系中存在的儿茶素的摩尔浓度呈高度的线性正相关。4种儿茶素组成不同的比例,以茶叶天然组成增效效果最明显。用伏安法测得的各儿茶素第一还原电位由高到低的次序为:(-)-EGCG>(-)-ECG>(-)-EGC≈(-)-EC,这一电位次序是儿茶素构成抗氧化循环的根本所在。  相似文献