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41.
石菖蒲(Acorus gramineus Soland)的精油经GC/MS/DS检测,硅胶加压柱层分离,得到一新的倍半萜,其在精油中的含量达60.30%,通过波谱方法确定了结构,并命名为石菖蒲酮(gramenone)。  相似文献   
42.
Cyanelles from Cyanophora paradoxa can easily be isolated and assayed for their carrier composition by the silicone oil filtering technique. The present investigation demonstrates a Pi-translocator transferring phosphate, dihydroxyacetone phosphate and 3-phosphoglycerate in a counter exchange mode in cyanelles as in chloroplasts of higher plants. The uptake of Pi is inhibited by dihydroxyacetone phosphate, phosphoglycerate and glucose-6-P, only poorly by phosphoenolpyruvate and not by 2-phosphoglycerate. The inhibitors pyridoxalphosphate and 4,4′diisothiocyanostilbene-2,2K'disulfonic acid at low concentration also affect Pi-uptake. Cyanelles probably transport photosynthate (reductant and ATP) by triosephosphates. This is the first demonstration of a phosphate translocator in an organism of a low evolutionary scale. Cyanelles also transport glucose which proceeds in two phases. In the lower concentration range (≤ 2.5 mM), glucose penetrates by facilitated diffusion, whereas transport follows first-order kinetics at higher amounts (> 2.5 mM). In the low concentration range, glucose-transport is affected by high concentrations of 3-O-methylglucose and fructose. The physiological role of the glucose-transport carrier in Cyanophora is doubtful. It may function in transporting glucose into cyanelles if the carbon level inside them becomes limiting, e.g. in dark periods.  相似文献   
43.
Medium chain hydrolase (MCH) is an enzyme which regulates the chain length of fatty acid synthesis specifically in the mammary gland of the rat. During lactation, MCH interacts with fatty acid synthase (FAS) to cause premature release of acyl chains, thus providing medium chain fatty acids for synthesis of milk fat. In this study we have investigated the ability of rat MCH to interact with the phylogenetically more distant FAS structure present in plant systems and to cause a perturbation of fatty acid synthesis. Inin vitro experiments, addition of purified MCH to rapeseed homogenates was found to cause a significant perturbation of fatty acid synthesis towards medium chain length products. The rat MCH gene was expressed in transgenic oilseed rape using a seed specific rape acyl carrier protein (ACP) promoter and a rape ACP plastid targeting sequence. Western analysis showed MCH protein to be present in transgenic seed and for its expression to be developmentally regulated in concert with storage lipid synthesis. The chimaeric preprotein was correctly processed and immunogold labelling studies confirmed MCH to be localized within plastid organelles. However, fatty acid analysis of oil from MCH-expressing rape seed showed no significant differences to that from control seed.  相似文献   
44.
Aedes aegypti L. (Diptera: Culicidae) is a vector for serious diseases in tropical regions. This pest is mainly controlled by commercial larvicides but the application of such products has led to environmental problems. Essential oils (EO) have been consistently reported as molecules with insecticidal activity and can be used to produce more environmentally friendly larvicides in the control of A. aegypti. In this study, the larvicidal effect of essential oils (EO) from the leaves of three Artemisia species was evaluated against Aaegypti. The oils were obtained from steam distillation and their chemical composition was determined by gas chromatography–mass spectrometry. The EO of Artemisia camphorata was the most active in the screening bioassay and presented LC50 and LC95 of 64.95 and 74.18 μg ml−1, respectively. In addition, we found that germacrene D-4-ol was the constituent responsible for the toxicity of this EO. Artemisia camphorata EO and its major constituent, germacrene D-4-ol, are promising for the development of natural larvicides against A. aegypti.  相似文献   
45.
Abstract: This paper presents an estimate of the total number of sea otters that died as a direct consequence of the oil spill that occurred when the T/V Exxon Valdez grounded in Prince William Sound, Alaska on 24 March 1989. We compared sea otter counts conducted from small boats throughout the Sound during the summers of 1984 and 1985 to counts made after the spill during the summer of 1989. We used ratio estimators, corrected for sighting probability, to calculate otter densities and population estimates for portions of the Sound affected by the oil spill. We estimated the otter population in the portion of Prince William Sound affected by the oil was 6,546 at the time of the spill and that the post-spill population in the summer of 1989 was 3,898, yielding a loss estimate of approximately 2,650. Bootstrapping techniques were used to approximate confidence limits on the loss estimate of about 500–5,000 otters. The wide confidence limits are a result of the complex scheme required to estimate losses and limitations of the data. Despite the uncertainty of the loss estimate it is clear that a significant fraction of the otters in the spill zone survived. We observed otters persisting in relatively clean embayments throughout the oil spill zone suggesting that the highly convoluted coastline of Prince William Sound produced refuges that allowed some sea otters in the oil spill area to survive.  相似文献   
46.
缬草挥发油化学成分的研究   总被引:1,自引:0,他引:1  
采用气相色谱-质谱联用仪对产于太白县的缬草根和茎叶中的挥发油成分分别进行分析,从根中鉴定出45种成分,以茎叶中鉴定出67种成分,并用GC测定了每一成分在该挥发油中的含量。  相似文献   
47.
Cancer is one of the main challenges of the health system around the world. This disease is increasing in developing countries and imposes heavy costs on patients and governments. On the other hand, despite various drugs, the death rate among cancer patients is still high and the current treatments have many harmful effects. In the traditional medicine of different countries, there are many medicinal plants that can be effective in the treatment of cancer. Ferula plants are traditionally used as spices and food or for medicinal purposes. Ferula assa-foetida is one of the famous plants of this genus, which has been used for the treatment of various diseases since ancient times. Among the main compounds of this plant, we can mention monoterpenes, sulfide compounds and polyphenols, which can show different therapeutic effects. This article has been compiled with the aim of collecting evidence and articles related to the anti-cancer effects of extracts, derived compounds, essential oils and nanoparticles containing Ferula assa-foetida. This review article was prepared by searching the terms Ferula assa-foetida and cancer, and relevant information was collected through searching electronic databases such as ISI Web of Knowledge, PubMed, and Google Scholar. Fortunately, the results of this review showed that relatively comprehensive studies have been conducted in this field and shown that Ferula assa-foetida can be very promising in the treatment of cancer.  相似文献   
48.
氯丙醇酯是国际上广泛关注的食品加工过程污染物,其水解产物氯丙醇对人体(特别是婴幼儿)危害风险较大。采用固相萃取与气相色谱-质谱(gas chromatography-mass spectrometry,GC-MS)联用技术,对食用植物油和含脂食品中的氯丙醇酯[3-氯-1,2-丙二醇脂肪酸酯(简称3-MCPD酯)和2-氯-1,3-丙二醇脂肪酸酯(简称2-MCPD酯)]进行检测。该方法准确度高(3-MCPD酯和2-MCPD酯的平均回收率分别为98.9%和96.5%)、灵敏度高(3-MCPD酯和2-MCPD酯的检出限分别为0.042 mg·kg-1和0.058 mg·kg-1)、重现性好(相对标准偏差均低于5%)。76批次监测样品中,3-MCPD酯和2-MCPD酯的含量分别为0.042~4.865 mg·kg-1(平均值为0.773 mg·kg-1)和0.058~2.592 mg·kg-1(平均值为0.469 mg·kg-1)。经机构间的协同验证和英国FAPAS样的能力验证,2种氯丙醇酯在0.200~3.000 mg·kg-1范围内线性良好,为进一步研究奠定了基础,同时也为食品加工企业严格控制生产过程建立了一种可行的检测方法。  相似文献   
49.
Cladanthus scariosus (Ball) Oberpr. & Vogt is endemic to Moroccan High Atlas. It is known under the vernacular names Irezghi or Irezgui. Three essential oil samples have been isolated from aerial parts and analyzed by combination of chromatographic and spectroscopic techniques [gas chromatography (GC) in combination with retention indices (RI), gas chromatography-mass spectrometry (GC/MS) and 13C-NMR spectroscopy]. The compositions of oil samples were dominated by monoterpenes: α-pinene sabinene, and terpinen-4-ol. Chamazulene and dihydrochamazulene isomers as well as various hemiterpene esters and analogs have been identified. To evidence a chemical variability, statistical analysis performed on 13 oil sample compositions allowed partitioning into three groups, mainly differentiated by their contents of sabinene, camphor, borneol, terpinen-4-ol, and germacrene D.  相似文献   
50.
Type 1 diabetes is characterized by insulin deficiency due to the destruction of pancreatic β cells, leading to hyperglycemia, which in turn induces vascular complications. In the current study, we investigated the effect of intraperitoneal administration of clove essential oil (CEO: 20 mg/kg body weight) on certain oxidative stress and glucose metabolism enzymes, as well as the expression of proinflammatory mediators. Administration of CEO to diabetic rats showed a significant decline in blood glucose levels, total cholesterol, and xanthine oxidase, compared to the streptozotocin group. Furthermore, these treated rats elicited a notable attenuation in the levels of lipid peroxides, and thiols groups in both liver and brain tissues. The activities of antioxidant and metabolic enzymes were reverted to normality in diabetic upon CEO administration. In addition to its protective effects on red blood cell hemolysis, CEO is a potent α-amylase inhibitor with an IC50=298.0±2.75 μg/mL. Also, treatment of diabetic rats with CEO significantly reduced the iNOS expression in the spleen. Our data showed that CEO has potential beneficial effects on diabetes, which can possibly prevent the pathogenesis of diabetic micro- and macrovascular complications.  相似文献   
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