稀土元素在植物中的生理效应

稀土元素是元素周期表中５７－７１的１５个镧系元素及与其性质十分相似的抗钇共１７种元素的统称,本文概述了稀土元素对改善植物矿质营养、促进植物光合作用,增强植物抗逆性方面的生理效应,还讨论了稀土元素与植物激素间关系。     

旁效应在基因治疗中的作用

目前化疗、放疗等治疗形式在癌症治疗效果上非常有限,而基因治疗是一种非常有前景的方法,旁效应是指部分细胞转入的特定基因片断会发生漂移,进入到没有转基因的细胞中,其在基因治疗中也起着重中之重的作用。本文简单介绍了一些基因转移系统、基因治疗方法,重点阐述旁效应在基因治疗中的作用及其产生机理,从而提高基因治疗的效率。     

旁效应在基因治疗中的作用

目前化疗、放疗等治疗形式在癌症治疗效果上非常有限,而基因治疗是一种非常有前景的方法,旁效应是指部分细胞转入的特定基因片断会发生漂移,进入到没有转基因的细胞中,其在基冈治疗中也起着重中之重的作用.本文简单介绍了一些基因转移系统、基因治疗方法,重点阐述旁效应在基因治疗中的作用及其产生机理,从而提高基因治疗的效率.     

农药对红海榄幼苗上藤壶的防治及其生理生态效应

设置4种施药频度(3、7、14和28d)和马拉硫磷4种浓度(分别为原农药浓度45%的1/200、1/400、1/600和1/800)处理,在初植红海榄(Rhizophora stylosa Griff)幼苗上开展了1年防治藤壶试验.结果表明:随施药浓度和频度提高,处理组幼苗上藤壶生物量显著降低,且所有处理组均显著低于对照组(P＜0.001);红海榄茎生物量和高度对施药浓度和频度不表现规律性反应;同一浓度的28d频度处理组幼苗的叶和根生物量及叶面积均低于其他频度处理组;在同一浓度下,施药频度越高叶数保持越多;3、7和14d频度处理组幼苗死亡率均较低,仅0～5%,28d频度处理组死亡率较高,为11%～22%,但对照组死亡率达39%;幼苗死亡率与藤壶生物量之间存在显著正相关关系(P＜0.001),与叶生物量、叶数、根生物量及新生器官生物量存在显著负相关关系(P＜0.001),与茎高、茎生物量、原繁殖体生物量等相关性不显著;施用农药造成红海榄幼苗叶绿素总量降低,Chl(a/b)比值上升,同时抗氧化酶系SOD和POD活性增大.建议在平均海平面高程的滩涂上造林,可采用频度14d、浓度1/800马拉硫磷喷雾防治藤壶.     

高等植物中硅元素的生理效应及其在农业生产中的应用

就高等植物中硅元素的含量,形态与分布,高等植物对硅的吸收与运输,施硅与植物生长发育,矿质营养状况和抗裂能力的关系,以及硅肥在农业生产上的应用作了概述。     

水稻覆膜旱作的生态生理效应

研究结果表明,水稻品种在旱作条件下其分蘖期、拔节长穗期、抽穗开花期和灌浆期耐旱性不同,采用地膜覆盖可有效阻挡地面蒸发,节水效率达６０～８５％,生育期延长７～９ｄ,分蘖力增强,最高分蘖数比水作的多１７０１×１０４·ｈｍ－２,有效穗数增加,但每穗粒数、结实率和千粒重下降,其产量水平与水作差异不显著．覆膜旱作水稻前期生长优势强,但后期叶面积指数（ＬＡＩ）、净同化率（ＮＡＲ）、群体生长率（ＣＧＲ）和比叶重等均有所降低,灌浆速度较慢,经济系数较低     

高静水压对小球藻的生理生化效应

对小球藻(Chlorella Vulgaris)进行高静水压处理,分别通过80MPa,300MPa静水压处理,观察高静水压处理时小球藻生理生化效应。实验结果表明,300MPa压力处理1h能够导致小球藻的大量死亡,少量存活的藻细胞经过5d的“停滞期”后开始正常生长。80MPa的压力下处理2h、6h、12h后小球藻的初期的生长速度明显加快,而到生长末期小球藻生长开始趋于平缓。小球藻干质量为12h实验组最大,而单位蛋白含量随着干质量的增加而下降,几种抗氧化酶活性为6h实验组具有最大活性。经过300MPa压力预处理1h后的小球藻再在80MPa压力下进行处理,发现小球藻干质量为2h再处理实验组最大,蛋白含量为6h再处理实验组最高,抗氧化酶的活性随着压力处理时间的增加而下降。     

南瓜多糖的多重生理效应研究进展

南瓜多糖属于杂化多糖,成分多样。目前,对其研究最多的功用是通过多种机制降低血糖,是公认的降糖活性物质。但随着对南瓜多糖不断深入地研究,人们发现它还具有降血脂、抗氧化、抗肿瘤、免疫增强等多种生理效应。就近年来南瓜多糖的多重生理效应的研究进展作一综述,为其进一步开发利用提供理论依据。     

纳米药物在癌症诊疗中的应用进展

癌症的诊断和治疗在近年取得了重大进步,但癌症目前仍是影响人类生存和健康的主因之一。提高癌症的早期诊断率和治疗效果具有重要意义。近来纳米技术在医学领域发展迅速,突破了传统癌症诊疗手段的固有局限性,并在临床上取得了一定成功。已有多个代表性药物获得新药批准或正处于临床试验阶段。然而,纳米药物仍面临肿瘤生物学的复杂性和异质性、药物安全性、纳米-生物界面的相互作用等挑战。该文阐述了近期纳米药物在肿瘤诊断以及化疗、放疗、光疗、化学动力治疗、免疫治疗和联合疗法等方面的应用进展,讨论了其在临床转化、生产和商业化所面临的问题,并对未来的发展机会和方向进行了展望。     

Protective Effect of Green Tea Extract and Tea Polyphenols against the Cytotoxicity of 1,4-Naphthoquinone in Isolated Rat Hepatocytes

The cytoprotective effect of green tea extract and its phenolic compounds against 1,4-naphthoquinone-induced hepatotoxicity was evaluated in primary cultured rat hepatocytes. After exposure to 1,4-naphthoquinone, lactate dehydrogenase (LDH) leakage and cell viability were both improved by the presence of the tea extract and tea polyphenols. This cytoprotective effect was related to the structure of tea polyphenols, the galloyl group of (–)-epigallocatechin-3-gallate and (–)-epicatechin-3-gallate being particularly effective. The production of liquid peroxidation by 1,4-naphthoquinone was not inhibited by the tea extract nor by tea polyphenol addition. After 2h of incubation, the protein thiol concentration was reduced by 1,4-naphthoquinone, but this reduction was prevented by the tea extract and tea polyphenols. The reduction in protein thiol content of the cells closely paralleled the LDH leakage and loss of cell viability. These results suggest that the mechanism of protection by tea polyphenols against 1,4-naphthoquinone-induced toxicity to rat hepatocytes was due to the maintenance of protein thiol levels.     

铁观音茶水提物对小鼠高尿酸血症的缓解作用

近年来,高尿酸血症（hyperuricemia,HUA）在人群中频发,危害性强,并发症多。为了探究日常饮品--半发酵茶铁观音茶水对于缓解HUA是否具有辅助作用,以小鼠为实验对象,采用氧嗪酸钾和次黄嘌呤联合法构建小鼠高尿酸血症模型,21只模型鼠随机分为模型组、铁观音茶水提物组、阳性药物组,7只非模型鼠作为对照。做不同处理2周后,取小鼠血清及肾、肝、小肠。观察各器官病理变化,从细胞层面鉴定铁观音茶水提物对高尿酸血症小鼠各脏器的影响;测定与HUA相关度较高的生化指标：血清尿酸（uric acid,UA）浓度、肝黄嘌呤氧化酶（xanthine oxidase,XOD）活力,以明确造模是否成功以及判断铁观音茶水提物对HUA是否具有缓解作用;利用qRT-PCR检测尿酸合成和排泄相关基因的mRNA表达水平,并利用Western blot检测肝XOD蛋白的表达水平,以从分子层面明确铁观音茶水提物对HUA的影响。病理切片显示,相比于阳性药物组,铁观音茶水提物组小鼠的肾和肝损害程度较轻;生化指标测定结果显示,铁观音茶水提物可降低血清尿酸水平,并且抑制XOD活性;从分子层面可以看出,铁观音茶水提物显著升高了尿酸重吸收转运体尿酸转运蛋白1(uric acid transporter 1,URAT1)和有机阴离子转运蛋白3(organic anion transporter 3,OAT3)的mRNA表达水平（P<0.05）,显著降低了葡萄糖转运子9（glucose transporter 9,GLUT9）和有机阴离子转运蛋白1(organic anion transporter 1,OAT1)的表达水平（P<0.05）。虽然qRT-PCR和Western blot提示,XOD的mRNA和蛋白质的表达水平升高,但尿酸生成量却下降,推测可能是铁观音茶水提物中的某种成分使得无催化活性的XOD蛋白表达增加进而对XOD基因的转录表达造成一种正反馈。研究提示,铁观音茶水提物对小鼠高尿酸血症具有缓解作用,其缓解高尿酸血症的作用与抑制XOD活性、干预尿酸生成过程和刺激或抑制相关阴离子转运体mRNA的表达相关。     

Scavenging Effect of Various Tea Extracts on Superoxide Derived from the Metabolism of Mutagens

We determine the superoxide formed in the self-degradation of mutagens activated by cytochrome enzymes and evaluated the scavenging effect of various tea extracts. Benzo[a]pyrene (B[a]P) and 2-amino-6-methyldipyrido(1,2-a:3′,2′-d)imidazole (Glu-P-1) each produced a large amount of superoxide after activation by cytochrome enzymes. However, 2-amino-3-methyl-imidazo(4,5-f)quinoline (IQ), 3-amino-1,4-dimethyl-5H-pyridol(4,3-b)indole (Trp-P-1) and alfatoxin B₁ (AFB₁) failed to generate a significant amount of superoxide. The addition of a tea extract to the reaction system marked inhibited the derivation of superoxide from Glu-P-1. However, the tea extracts showed weaker inhibition of the B[a]P-mediated formation of superoxide. Among the four teas tested, the oolong tea extract tended to exhibit the strongest inhibitory effect. Our results suggest that the chemopreventive efficacy of a tea extract is partly associated with its antioxidative activity.     

A Hair Growth-Promoting Effect of Chinese Black Tea Extract in Mice

Chinese black tea extract (CBTE) fermented with Aspergillus sp. significantly promoted hair growth after 2 weeks of topical application in shaved 6 week-old male C3H/He mice. The hair growth-promoting effect of CBTE was potentiated synergistically by capsaicin, which has no effect on hair growth by itself. CBTE displayed an affinity for estrogen receptor (ER)α, with an IC₅₀ value of 74.8 µg/mL. This effect of CBTE might be mediated by the ERs, since a similar effect induced by orally administered soy isoflavone, a mixture of ERs ligands, has been reported to be synergistically potentiated by capsaicin.     

十两茶水提物降糖作用及机制研究

探讨了湖南安化黑茶的主要品种十两茶水提物的降糖作用及机制.选用6～8周龄db/db自发性糖尿病模型小鼠,每日灌胃给予3个不同剂量的十两茶水提物(100、200、400 mg/kg),连续28 d.每周测定空腹血糖值,实验结束时检测糖耐量和胰岛素水平.研究结果显示,十两茶水提物400 mg/kg给药28 d就能显著降低db/db糖尿病小鼠空腹血糖和改善其对葡萄糖耐受能力.同时,十两茶水提物能显著降低db/db糖尿病小鼠血清胰岛素水平,增加葡萄糖耐量试验胰岛素的释放.结果显示十两茶水提物对2型糖尿病小鼠具有很好的降糖作用,其作用机制与增加胰岛素敏感性有关.     

五倍子提取物抑菌效果及稳定性研究

采用琼脂打孔法和平板涂布法,观察五倍子提取物对常见致病菌的抑菌效果,并以金黄色葡萄球菌、大肠杆菌的抑菌环直径为参考指标,考察紫外光照时间、温度及介质pH值对五倍子提取物抑菌活性的影响。结果表明,五倍子提取物对革兰氏阳性菌的抑菌效果明显强于革兰氏阴性菌,在稳定性研究过程中发现,光照时间、温度及介质pH值对五倍子提取物的抑菌效果影响较大,因此在选用五倍子提取物作植物抑菌剂时应现配现用。     

酸提高绿茶提取物对脂肪酸合酶的抑制活性

脂肪酸合酶和肥胖、癌症等人类重大疾病相关.获取高活性脂肪酸合酶抑制剂有重要应用价值.50％乙醇的绿茶提取物具有抑制脂肪酸合酶和经口服降低大、小鼠体重的功能.该提取物在酸的作用下可明显地提高其抑制脂肪酸合酶的能力.采用1 mol/L硫酸或盐酸在100℃下处理绿茶提取物,发现该提取物对脂肪酸合酶的抑制活性随时间逐步提高.在25℃至120℃温度下,提高处理温度使抑制活性提高的速度加快和程度加大. 用1 mol/L盐酸120℃处理35 min或3 mol/L盐酸100℃处理30 min可使绿茶提取物抑制脂肪酸合酶的半抑制浓度下降20倍左右,达到1 μg/ml以下.用pKa值4.76至1.27的1 mol/L浓度的4种有机酸在100℃作用150 min使绿茶提取物抑制活性分别提高到1.48至5.84倍.提高酸的浓度也使被作用的提取物的抑制活性提高的更多.表现抑制活性提高的速度及程度和氢离子浓度正相关.判断绿茶提取物在酸作用下抑制活性的提高来源于其中所含儿茶素在氢离子作用下发生了化学变化.初步实验表明其变化过程比较复杂,确定其分子机制还需进一步的研究工作.     

Enhancement of the Phagocytic Activity of Macrophage-Like Cells with a Crude Polysaccharide Derived from Green Tea (Camellia sinensis) Extract

To identify the immunostimulants included in green tea extract, we investigated a crude tea polysaccharide related to increases in phagocytic activity using macrophage-like cells, and found that the crude tea polysaccharide from immature tea leaves included many RNAs as compared with that from mature tea leaves. Furthermore, the crude tea polysaccharide increased phagocytosis through toll-like receptor 7.     

Green Tea Extract (Camellia sinensis) Fermented by Lactobacillus fermentum Attenuates Alcohol-Induced Liver Damage

The preventive effects of glycomacropeptide (GMP) against intestinal infection were investigated, and conjugates of GMP with xylooligosaccharide (XOS) and carboxymethyldextran (CMD) were prepared by the Maillard reaction to enhance the effect of GMP. The binding ability of GMP to intestinal pathogenic bacteria was evaluated by a binding assay with biotinylated bacteria. GMP showed the ability to bind to Salmonella enteritidis and enterohemorrhagic Escherichia coli O157:H7 (EHEC O157). This binding ability was decreased by a sialidase treatment and completely eliminated by periodate oxidation. These results indicate that such carbohydrate moieties as sialic acid in GMP are involved in binding to S. enteritidis and EHEC O157. The preventive effect of GMP on the adhesion of pathogenic bacteria to Caco-2 cells was also investigated. GMP showed an inhibitory effect on the adhesion of EHEC O157 in a dose-dependent manner, although it was not a potent inhibitor of the adhesion of Salmonella infection. However, in the case of Salmonella infection, GMP–XOS and GMP–CMD significantly suppressed IL-8 production which was the index of infection. Our results indicate GMP to be a promising agent for preventing intestinal infection.     

绿茶粗提物对耻垢分枝杆菌的生长抑制研究

采用乙酸乙酯在中性条件下萃取绿茶,得到含有表没食子儿茶素没食子酸酯(Epigallocatechin gallate,EGCG)的粗提物。通过纸片琼脂扩散法和细菌生长曲线来评价绿茶粗提物对耻垢分枝杆菌的抑菌效果,利用透射电子显微镜(Transmission electron microscopy,TEM)观察其对耻垢分枝杆菌细胞壁结构的影响。结果显示,绿茶粗提物对耻垢分枝杆菌生长产生明显抑制作用,且抑菌作用随着浓度的升高逐渐加强;经绿茶粗提物处理的耻垢分枝杆菌细胞壁呈现膨出、变形等形态学变化。因此,绿茶粗提物具有抑制耻垢分枝杆菌生长的功能,其作用机制可能与其主要成分EGCG影响细胞壁肽聚糖的生物合成有关。