Isolation and characterization of superoxide dismutase from wheat seedlings     

Lai LS  Chang PC  Chang CT 《Journal of agricultural and food chemistry》2008,56(17):8121-8129

Two major superoxide dismutases (SODs; SODs I and II) were found in the crude enzyme extract of wheat seedlings after heat treatment, ammonium sulfate fractionation, anionic exchange chromatography, and gel permeation chromatography. The purification fold for SODs I and II were 154 and 98, and the yields were 11 and 2.4%, respectively. SOD I was further characterized. It was found that SOD I from wheat seedlings is a homodimer, with a subunit molecular mass of 23 kDa. Isoelectric focusing electrophoresis (IEF) and zymogram staining results indicated that the isoelectric point of SOD I is 3.95. It belongs to the MnSOD category due to the fact that it was insensitive to KCN or hydrogen peroxide inhibitor. This MnSOD from wheat seedlings was found to be stable over pH 7-9, with an optimum pH of 8, but was sensitive to extreme pH, particularly to acidic pH. It was stable over a wide range of temperatures (5-50 degrees C). Thermal inactivation of wheat seedling MnSOD followed first-order reaction kinetics, and the temperature dependence of rate constants was in agreement with the Arrhenius equation. The activation energy for thermal inactivation of wheat seedling MnSOD in the temperature range of 50-70 degrees C was found to be 150 kJ/mol. HgCl2 and SDS at a concentration of 1.0 mM significantly inhibited enzyme activity. Chemical modification agents, including diethyl pyrocarbonate (2.5 mM) and Woodward's reagent K (50 mM), significantly inhibited the activity of wheat seedling SOD, implying that imidazole groups from histidine and carboxyl groups from aspartic acid and glutamic acid are probably located at or near the active site of the enzyme.  相似文献   

Chemoinhibitory effect of mulberry anthocyanins on melanoma metastasis involved in the Ras/PI3K pathway     

Huang HP  Shih YW  Chang YC  Hung CN  Wang CJ 《Journal of agricultural and food chemistry》2008,56(19):9286-9293

Anthocyanins richly exist in mulberry plants and have been well characterized to have various bioactive properties. However, the antimetastasis properties of mulberry anthocyanins (MACs) remain unclear. The objectives of this study were to investigate the inhibitory effects of MACs on the metastasis of B16-F1 cells under noncytotoxic concentrations. Further investigation revealed that the antimetastatic effect of MACs was also evident in a C57BL/6 mice model. First, MACs exhibited an inhibitory effect on the migration ability by wound healing assay and Boyden chamber assay. In the cancer cell metastasis process, matrix degrading proteinases are required. B16-F1 cells treated with MACs at various concentrations showed reduced extracellular matrix (ECM) proteinases including matrix metalloproteinase-2 (MMP-2) and matrix metalloproteinase-9 (MMP-9) by gelatin zymography assay. The results of the Western blotting assay demonstrated that the expression levels of Ras, phosphoinositide 3-kinase (PI3K), phospho-Akt, and nuclear factor kappa B (NF-kappaB) in the MACs-treated B16-F1 cells were reduced. Therefore, it was suggested that MACs could mediate B16-F1 cell metastasis by reduction of MMP-2 and MMP-9 activities involving the suppression of the Ras/PI3K signaling pathway. Besides, B16-F1 melanoma cells were also injected into the right groin of the C57BL/6 mice, and the mice were fed with MACs at the same time. The hematoxylin-eosin stain (H&E stain) and immunohistochemistry stain showed that the MACs inhibited the mtastasis of B16-F1 cells in vivo. Taken together, the findings proved the inhibitory effect of MACs on the growth and metastasis of B16-F1 cells. These results indicated that MACs might be offered for future application as an antimetastatic agent.  相似文献   

A cell-based screening identifies compounds from the stem of Momordica charantia that overcome insulin resistance and activate AMP-activated protein kinase     

Cheng HL  Huang HK  Chang CI  Tsai CP  Chou CH 《Journal of agricultural and food chemistry》2008,56(16):6835-6843

Treatment of insulin resistance is a critical strategy in the prevention and management of type 2 diabetes. The crude extracts from all parts of Momordica charantia L. have been reported by many studies for the effective treatment of diabetes and related complications. However, the exact ingredients responsible for the hypoglycemic effect and the underlying mechanism of their actions have not been well characterized because of the lack of a proper assay and screening system. A new cell-based, nonradioactive, and nonfluorescent screening method was demonstrated in this study to screen for natural products from the stem of M. charantia, aiming to identify hypoglycemic components that can overcome cellular insulin resistance. The results suggest triterpenoids being potential hypoglycemic components of the plant and the mechanism underlying their action involving AMP-activated protein kinase.  相似文献   

Speciation analysis of mercury in cereals by liquid chromatography chemical vapor generation inductively coupled plasma-mass spectrometry     

Lin LY  Chang LF  Jiang SJ 《Journal of agricultural and food chemistry》2008,56(16):6868-6872

A simple and rapid procedure for the separation and determination of inorganic, methyl, and ethyl mercury compounds was described using liquid chromatography (LC) followed by vapor generation inductively coupled plasma-mass spectrometry (VG-ICP-MS). Well resolved chromatograms were obtained within 5 min by reversed-phase liquid chromatography with a C8 column as the stationary phase and a pH 4.7 solution containing 0.5% v/v 2-mercaptoethanol and 5% v/v methanol as the mobile phase. The separated mercury compounds were converted to mercury vapors by an in situ nebulizer/vapor generation system for their introduction into ICP. The concentrations of NaBH4 and HNO3 required for vapor generation were also optimized. The method was applied for the speciation of mercury in reference materials NIST SRM 1568a Rice Flour and NIST SRM 1567a Wheat Flour and also rice flour and wheat flour samples purchased locally. The accuracy of the procedure was verified by analyzing the certified reference material NRCC DOLT-3 Dogfish Liver for methyl mercury. Precision between sample replicates was better than 13% for all the determinations. The detection limits of the mercury compounds studied were in the range 0.003-0.006 ng Hg mL(-1) in the injected solutions, which correspond to 0.02-0.06 ng g(-1) in original flour samples. A microwave-assisted extraction procedure was adopted for the extraction of mercury compounds from rice flour, wheat flour, and fish samples using a mobile phase solution.  相似文献   

十字花科蔬菜害虫生物防治研究进展   总被引：3，自引：0，他引：3  

赵红  薛东  杨长举 《湖北植保》2005,12(6):34-38

十字花科蔬菜主要害虫有菜青虫、小菜蛾、甜菜夜蛾、猿叶虫等,其中有些害虫抗药性的迅速增加导致频繁暴发,因此生物防治对于防治十字花科蔬菜害虫是至关重要的。本文综述了国内外目前对十字花科蔬菜害虫天敌昆虫、病原微生物的调查研究进展,并探讨对植物提取物和昆虫生长调节刑等的利用现状。  相似文献   

Proteome analysis of greenhouse-cultured lettuce with the natural soil mineral conditioner illite     

Jong-Soon Choi  Seong-Woo Cho  Tae-Seon Kim  Kun Cho  Seok-Soon Han  Hong-Ki Kim  Sun-Hee Woo  Keun-Yook Chung 《Soil biology & biochemistry》2008,40(6):1370-1378

The natural soil mineral conditioner illite effectively improved the germination and growth of lettuce when applied in particulate or powdered form. When illite was given in particulate and powdered forms, the germination rate of lettuce seeds improved remarkably up to 93% and 133%, respectively. Contrary to the developmental effects, the growth rate of lettuce treated with particulate illite improved slightly by 23%; powdered illite had no significant effects on lettuce growth rate. Thus, illite primarily affects seed germination rather than the growth of lettuce. To examine illite-induced proteins related to lettuce growth, differentially expressed proteins in lettuce leaves were analyzed by two-dimensional gel electrophoresis (2-DE) and matrix-assisted laser desorption ionization-time of flight/time of flight mass spectrometry (MALDI-TOF/TOF MS) followed by Mascot search. From the proteomic analysis, five down-regulated proteins were identified related to storage protein, carbon metabolism and energy conversion. Three up-regulated proteins were related to energy production/conversion and carbon fixation. These results demonstrate that illite treatment as a soil conditioner helps lettuce seed germination and lettuce growth by regulating carbon metabolic flux.  相似文献   

荞麦品种改良与产业发展现状及趋势分析     

杨崇庆  常克勤  穆兰海  杜燕萍  张久盘  李耀栋  张晓娟 《作物杂志》2021,37(2):28-801

根据国内外荞麦生产现状及存在的问题,对未来荞麦产业发展、品种改良方向及品种选育技术进行了讨论。近年来,世界范围内荞麦种植面积稳中有升,荞麦消费量呈增加趋势,但荞麦生产中普遍存在生产条件差、产量低、品种改良难和不适宜机械化生产等问题,因此广适、高效、优质和高产等特性是荞麦品种改良的目标,传统杂交技术与分子育种技术的结合是未来荞麦品种改良的主要手段。  相似文献   

安徽省砀山县丰产农机合作社:创新模式发展优势服务     

常志强 《农业机械》2020,(1):44-45

砀山县丰产农机服务专业合作社位于安徽省宿州市砀山县朱楼镇朱楼村,成立于2015年5月13日。合作社目前占地1.33 hm^2(20余亩),拥有成员200余人,拖拉机40多台,收割机18台,灌溉机械14套,植保飞机80多架,烘干机6组,配套农具230多台(套),机械资产达到1 200余万元。  相似文献   

苗期调控对晚播小麦产量及氮素利用的影响     

刘阿康  王德梅  王艳杰  杨玉双  马瑞琦  高甜甜  王玉娇  阚茗溪  赵广才  常旭虹 《作物杂志》2021,37(2):116-121

针对冬小麦因播期推迟造成产量损失的问题,以2个不同分蘖能力的冬小麦品种中麦8号和航麦501为供试材料,研究苗期覆膜和补施氮肥对晚播小麦产量及氮素利用的影响。试验设置3个播期：10月5日适期播种（S0,对照）、10月15日适当晚播（S1）和10月25日过晚播（S2）。结果表明：随着播期推迟,小麦产量逐渐降低。晚播条件下,苗期覆膜和补施氮肥可调控冬小麦产量构成因素、农艺性状、茎蘖生长、成穗率以及氮素的吸收利用。综合而言,晚播条件下,覆膜和补施氮肥有利于提高小麦穗长、总小穗数及冬前群体数量;同时,覆膜可显著提高2个品种晚播条件下的分蘖成穗率和过晚播条件下的植株氮素积累量（PNA）及氮肥偏生产力（PFP）,增幅分别为46.4%~89.1%、12.7%~26.5%和19.5%~20.1%;补施氮肥在过晚播条件下有利于成穗率的提高,增幅为18.5%~34.7%。2种调控措施均有利于增加晚播小麦产量,增幅达1.4%~19.5%。但不同分蘖力的小麦对2种调控措施的响应存在差异。综合考虑产量及氮素利用等各方面因素,在晚播条件下,相比于补施氮肥,苗期覆膜更有利于提高晚播小麦产量,弥补晚播造成的产量损失,但在实际操作和节约生产成本方面,前者优于后者。  相似文献   

高压直流接地极对埋地管道腐蚀的影响和管控思考     

胡亚博  吴志平  吴世勤  倪少清  常景龙 《油气储运》2021,(3):256-262

高压直流输电、油气长输管道建设促进了全国范围内的能源优化配置,但高压直流接地极放电对埋地管道的强直流干扰问题应该引起足够关注。为进一步加强相关风险管控,回顾中国高压直流输电网的发展历程,对高压直流接地极放电影响管道的典型特点进行分析,结合当前实际提出后续风险管控的发展方向。研究结果表明:邻近油气长输管道路由的高压直流输电线路和接地极对管道的影响具有干扰时间不确定、干扰机理复杂、干扰程度大及缓解困难的特点,是管道当前面临的突出安全风险。高压直流输电网调试或故障运行过程中,接地极单极放电会加速管道腐蚀。后续应从加强沟通协调和联合测试,深化腐蚀机理和规律研究,采取综合治理措施等方面提升检测、研究及治理水平,全方位保障国家能源通道的安全稳定。  相似文献