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1.
酪氨酸酶基因工程菌产黑色素的发酵条件研究   总被引:14,自引:1,他引:13  
研究了表达酪氨酸酶的基因工程菌产黑色素的条件。WY8能在酪素平板上产生可溶性黑色素,在添加酪氨酸的液体LB培养基中的黑色素产率是基因来源菌-Pseudomonas maltophilia的5倍。用正交试验法找到适宜发酵产黑色素的培养基,对摇瓶装置,菌龄,底物浓度,发酵温度和pH等因素的影响作了进一步探讨。  相似文献
2.
栀子苷的药理学研究新进展   总被引:7,自引:0,他引:7  
国内外有关栀子苷的药理作用研究报道颇多,表明其具有抗哮喘、抗炎镇痛、保肝利胆、抗病毒、抗肿瘤等作用,且对神经系统和心脑血管疾病也有治疗作用。近年来的实验研究发现,栀子苷具有抗氧化、促进黑色素生成、抑制NF-κB/IκB通路和细胞黏附分子产生等药理活性。综述栀子苷的药理学研究新进展,为栀子苷的开发利用提供依据。  相似文献
3.
Through the screening of our in-house chemical compound library, we found a novel melanin-concentrating hormone (MCH) receptor antagonist, T-226296, a (-) enantiomer of N-[6-(dimethylamino)-methyl]-5,6,7,8-tetrahydro-2-naphthalenyl]-4'-fluoro[1,1'-biphenyl]-4-carboxamide. T-226296 exhibited high affinity for cloned human and rat MCH receptors (SLC-1) in receptor binding assays (IC50=5.5+/-0.12 nM for human SLC-1; 8.6+/-0.32 nM for rat SLC-1). T-226296 had high selectivity over other receptors, including the second subtype of the MCH receptor, SLT (MCH2), transporters and ion channels. In Chinese hamster ovary (CHO) cells expressing human SLC-1, T-226296 reversed the MCH-mediated inhibition of forskolin-stimulated cAMP accumulation, inhibited MCH-induced intracellular Ca2+ increase, and also inhibited MCH-stimulated arachidonic acid release. In rats, oral administration of T-226296 (30 mg/kg) almost completely suppressed the food intake induced by intracerebroventricular injection of MCH. These results clearly indicate that T-226296 is a novel, orally active and selective MCH receptor antagonist that will be promising for further exploring the physiology and pathophysiology of MCH-SLC-1 signaling.  相似文献
4.
Iron-binding characteristics of neuromelanin of the human substantia nigra   总被引:5,自引:0,他引:5  
The vulnerability of the dopaminergic neurons of the substantia nigra (SN) in Parkinson's disease has been related to the presence of the pigment neuromelanin (NM) in these neurons. It is hypothesised that NM may act as an endogenous storage molecule for iron, an interaction suggested to influence free radical production. The current study quantified and characterised the interaction between NM and iron. Iron-binding studies demonstrated that both NM and synthetically-produced dopamine melanin contain equivalent numbers of high and low-affinity binding sites for iron but that the affinity of NM for iron is higher than that of synthetic melanin. Quantification of the total iron content in iron-loaded NM and synthetic melanin demonstrated that the iron-binding capacity of NM is 10-fold greater than that of the model melanin. This data was in agreement with the larger iron cluster size demonstrated by M?ssbauer spectroscopy in the native pigment compared with the synthetic melanin. These findings are consistent with the hypothesis that NM may act as an endogenous iron-binding molecule in dopaminergic neurons of the SN in the human brain. The interaction between NM and iron has implications for disorders such as Parkinson's disease where an increase in iron in the SN is associated with increased indices of oxidative stress.  相似文献
5.
一株黑色素高产细菌的发酵条件研究   总被引:3,自引:0,他引:3  
采用正交试验和单因素试验研究了黑色素高产细菌BFHM2002获得高产所需的发酵条件.结果表明其最适培养基为(%,w/v):蛋白胨2、甘露醇0.4、碳酸钙0.2、氯化钠0.5、L-酪氨酸0.1,pH6.0.在优化条件下,产量可达3.25mg/ml.  相似文献
6.
从棘孢小单孢福建亚种的发酵液中提取的黑色素生物合成抑制剂MA-18,经提取,纯化和理化性质鉴别,根据元素分析、EI-MS和^13C-NMR的结果,确定其分子式为C7H7NO2,分子量137。分析1H-NMR和^13C-NMR主要信号的归属,推测MA-18为苯的衍生物。  相似文献
7.
抗色素美容方剂在体外对黑色素聚合过程的影响   总被引:3,自引:0,他引:3  
本文基于皮肤色素形成的生化反应聚合过程的生理基础,体外模拟聚合过程测定抗色素美容方剂及其所含主药:白术、白蒺藜、当归、川芎对多巴自氧聚合、紫外线促多巴聚合和促黑色素分解作用的影响。  相似文献
8.
Summary The concentration of chlorpromazine (CPZ) in hair was measured to demonstrate its value as an index of individual dosage history and compliance. An animal study using pigmented rats was conducted to confirm the dose-dependent accumulation of CPZ in hair. The concentration of CPZ in hair, newly regrown on a denuded area of the back after the administration of CPZ for 3 weeks, was 4.6, 8.5 and 16.6 ng·mg–1 hair after daily doses of 1.25, 2.5 and 5 mg·kg–1·day–1, respectively, significantly correlated with the daily dose.The concentration of CPZ in black hairs collected from 23 Japanese patients, who had been taking CPZ in fixed daily doses (30–300 mg/day), ranged from 1.6 to 27.5 ng·mg–1, and was significantly correlated both with the daily dose and with the trough plasma concentration at steady state. Several strands of hair collected from each of 5 patients, whose doses of CPZ had been changed within several months before sampling, were cut into 1-cm pieces successively from the scalp end and the concentration of CPZ in each piece was measured. With the assumption of a hair growth rate of 1 cm per month, the individual history of CPZ doses in all patients could be deduced from the distribution of CPZ along the hair shaft. In 5 patients with grizzled hair the concentration of CPZ in white hairs was much lower (<10%) than in black hairs, suggesting that the strong affinity of CPZ for hair melanin may explain the accumulation of CPZ in black hair.The concentration of co-administered haloperidol (HP) in plasma and hair was also measured in 11 out of 23 patients. The CPZ concentration in hair was much lower than that of HP (about 0.3 to 7.8%), whether the comparison was made on the basis of daily dose or plasma concentration. This finding is discussed in relation to the affinity of the compounds for their melanin and photochemical stability.  相似文献
9.
Catecholamine content of pigmented and nonpigmented tissues of the rabbit   总被引:2,自引:0,他引:2  
Norepinephrine and dopamine content of various tissues from albine and nonalbino (black fur) rabbits were chemically determined. Although norepinephrine content of the nonpigmented iris (7.93 μg/g) and the pigmented iris (6.8 μg/g) did not differ significantly, the latter type contained very high amounts of dopamine (6.5 μg/g). As compared to that from the albino animal, the retina from nonalbino animals also contained slightly higher levels of dopamine. Thus, in addition to previously proposed neurotransmitter role of dopamine in the retina, it may also serve as precursor for the biosynthesis of melanin in the pigmented tissues.  相似文献
10.
7种美白化合物对皮肤黑素细胞的体外生物学效应   总被引:2,自引:0,他引:2  
目的 研究7种美白化合物对体外培养的皮肤黑素细胞的生物学效应。方法 利用B-16小鼠黑素瘤细胞株,以左旋多巴为底物测定细胞内酪氨酸酶活性,采用比色法测定细胞中黑色素含量,以溴化二苯四偶氮法(MTT法)测定化合物对黑素细胞活力的影响。结果 各化合物对黑素细胞酪氨酸酶活性和黑素生成量呈浓度依赖性抑制,对黑素细胞活力均有不同程度的影响。结论 这7种化合物均能抑制黑素细胞的黑色素生成。  相似文献
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