玉米蛋白粉中黄体素和玉米黄素的分离与定性

利用溶剂萃取、薄层层析对玉米蛋白粉中黄体素和玉米黄素进行了提取和分离.通过薄层层析的相对迁移率、与AgNO3的显色反应、紫外 可见吸收光谱、高效液相色谱保留时间及液质联用所得到的相对分子质量信息,对分离所得黄体素和玉米黄素进行了定性研究,为玉米蛋白粉中黄体素和玉米黄素的进一步研究和开发利用奠定了基础.     

同工麦胚凝集素Ⅱ对乳腺癌细胞的增殖抑制作用

通过增殖抑制试验、细胞形态观察和细胞周期测定,研究了同工麦胚凝集素Ⅱ（WGAⅡ）对于体外培养的MCF-7和SHZ两种乳腺癌细胞的增殖抑制作用.结果表明最大抑制率均出现于加药后72h,其中SHZ.尤为敏感.WGAⅡ对SHZ细胞的LD50为10μg/ml.WGAⅡ作用使细胞皱缩或拉长,部分细胞簇集成团,有些细胞脱壁,细胞表面反光性变差.细胞膜皱缩、外突或粘连,有的小泡破裂,或脱落形成凋亡小体.WGAⅡ将SHZ细胞阻断在G1/S期,干扰了肿瘤细胞的正常增殖活动.     

叶黄素和玉米黄素抑制口腔上皮细胞癌增殖的实验研究

为阐明玉米蛋白粉类胡萝卜素提取物叶黄素和玉米黄素对人口腔上皮癌细胞株KB凋亡的诱导作用,探讨其分子生物学机制。本文采用单细胞凝胶电泳、DNA凝胶电泳、流式细胞术检测叶黄素和玉米黄素诱导口腔癌细胞凋亡的情况。结果发现:单细胞凝胶电泳显示玉米蛋白粉叶黄素和玉米黄素能造成KB细胞DNA损伤、DNA凝胶电泳显示能使KB细胞DNA发生明显的降解,DNA周期分析主要阻断口腔癌细胞由G1向S期转变;流式细胞仪检测明显抑制人口腔癌细胞株KB中bcl-2基因的蛋白表达,明显升高p53、Bax基因的蛋白表达;说明玉米蛋白粉类胡萝卜素提取物叶黄素和玉米黄素具有明显抑制口腔上皮癌细胞增殖、并诱导其凋亡的作用。     

玉米蛋白粉中玉米黄素对人口腔鳞癌细胞株KB增殖的抑制

研究了玉米蛋白粉中玉米黄素的抗肿瘤活性。采用体外培养的人癌细胞株——人口腔鳞癌KB细胞作为对象，观察玉米黄素对抑瘤活性、细胞周期的影响，发现玉米黄素对KB细胞24h的半数抑制浓度IC50为35μmol／L，在20μmol／L时即明显抑制KB细胞的对数生长；细胞周期分析显示时相左移，G1期细胞百分率增多，S期、G2＋M期百分率降低．DNA凝胶电泳显示30μmool／L玉米黄素作用72h能使KB细胞的DNA发生明显的降解．因此从玉米蛋白粉中提取的玉米黄素能明显抑制KB细胞生长，其抗肿瘤活性强，对细胞周期的影响提示G0期阻滞．     

纳豆脂肽对人乳腺癌细胞MCF-7的作用

目的:研究纳豆脂肽对人乳腺癌细胞MCF-7的作用。方法:通过酸沉、有机溶剂提取以及活性炭吸附等方法从纳豆发酵液中提取纳豆脂肽。MTT法测定纳豆脂肽对MCF-7细胞增殖的影响;流式细胞仪检测纳豆脂肽对MCF-7细胞凋亡和周期的影响。结果:纳豆脂肽对人乳腺癌细胞MCF-7的增殖有显著抑制作用且抑制率随纳豆脂肽浓度的增加而上升,其IC50为3.68μg/mL。纳豆脂肽可以影响MCF-7细胞的凋亡率,并将细胞周期阻滞在S期。结论:纳豆脂肽能显著抑制体外培养的人乳腺癌细胞MCF-7的增殖,引起人乳腺癌细胞MCF-7的凋亡。     

6种类胡萝卜素对人乳腺癌细胞株细胞间隙连接通讯功能影响的比较

目的：探讨类胡萝卜素对乳腺癌细胞MDA-MB-435S和MCF-7细胞的细胞间隙连接通讯功能的影响。方法：类胡萝卜素分别与乳腺癌细胞MDA-MB-435S、MCF-7共培养,划痕标记染料示踪技术检测类胡萝卜素对乳腺癌细胞间隙连接通讯功能的影响。结果：β-胡萝卜素、虾青素和番茄红素对MDA-MB-435S细胞的细胞间隙连接通讯功能具有较强的促进作用;角黄素、玉米黄素和玉米黄素双棕榈酸酯对MDA-MB-435S细胞的细胞间隙连接通讯功能的影响不明显;β-胡萝卜素、虾青素和角黄素对MCF-7细胞的细胞间隙连接通讯功能具有较强的促进作用;番茄红素、玉米黄素和玉米黄素双棕榈酸酯对MCF-7细胞间隙连接通讯功能的影响不明显。     

玉米蛋白粉中叶黄素和玉米黄素对口腔癌细胞DNA的损伤作用

研究玉米蛋白粉中叶黄素和玉米黄素对人口腔癌KB细胞的作用机制。在人口腔癌KB细胞的细胞培养液中分别加入40μL/L、60μL/L叶黄素和30μL/L、40μL/L玉米黄素,分别培养48h、72h。用单细胞凝胶电泳(SCGE)检测叶黄素和玉米黄素对人口腔癌KB细胞DNA损伤程度。玉米蛋白粉中叶黄素和玉米黄素可引起KB细胞DNA链断裂,细胞尾长、尾DNA百分含量和尾矩显著高于对照组,差异有统计学意义(P<0.01)。叶黄素和玉米黄素能导致人口腔癌细胞KB的DNA损伤,抑制肿瘤细胞生长。     

蒲公英萜醇对人乳腺癌细胞MCF-7增殖及凋亡的影响

目的：探讨蒲公英萜醇对人乳腺癌细胞MCF-7增殖、凋亡的影响及其可能的分子机制。方法：体外培养人 乳腺癌细胞MCF-7,采用噻唑蓝比色法和平板克隆实验检测蒲公英萜醇对MCF-7细胞增殖的影响;Hoechst 33342荧 光染色法检测细胞凋亡的形态变化;Western blot法检测凋亡相关蛋白的表达。结果：蒲公英萜醇对人乳腺癌细胞 MCF-7有明显的增殖抑制作用（P＜0.05）;Hoechst染色结果显示,给药后细胞核内染色质凝集,核固缩,可见凋 亡小体;Western blot结果显示,蒲公英萜醇可极显著提高Bax/Bcl-2的比值（P＜0.01）以及上调活化型Caspase-3/9 的表达（P＜0.01）,下调PARP的表达（P＜0.01）。结论：蒲公英萜醇能够明显抑制人乳腺癌细胞MCF-7增殖, 并通过线粒体途径诱导其凋亡。     

Delphinidin抗乳腺癌EMT体外效应研究

研究飞燕草素(Delphinidin,Dp)抑制HER-2~+乳腺癌细胞(MDA-MB-453)和HER-2~-乳腺癌细胞(MCF-7)上皮细胞-间充质转化(EMT)效应。将不同浓度Dp分别处理MDA-MB-453和MCF-7细胞48 h,于倒置显微镜观察细胞形态及数量变化后,用蛋白质免疫印迹法和逆转录聚合酶链反应检测EMT标志性蛋白E-cadherin、N-cadherin、Vimentin、Fibronectin及关键调控因子锌指转录因子(Snail 1)表达。80μmol/L和100μmol/L的Dp能使MDA-MB-453和MCF-7乳腺癌细胞的E-cadherin标志蛋白表达上调,而降低与细胞迁移和侵袭能力有关的N-cadherin、Vimentin、Fibronectin及Snail因子表达水平。Dp体外具有抗MDA-MB-453和MCF-7乳腺癌EMT的效应,研究结果可为植物黄酮类化合物抗乳腺癌转移及辅助治疗提供新支撑。     

苦荞萌发物中生物活性黄酮对人乳腺癌细胞增殖的抑制作用

以萌发期(1～6d)的苦荞芽粉为原料,采用铝盐显色可见分光光度法和HPLC 法,探明萌发期(1～6d)苦荞芽粉乙醇提取物中总黄酮、芦丁和槲皮素含量的变化趋势。以人乳腺癌细胞MCF-7 为模型,采用噻唑蓝(MTT)比色法,比较萌发期(1～6d)的苦荞芽粉乙醇提取物对人乳腺癌细胞体外的增殖抑制率。结果表明：苦荞芽粉乙醇提取物具有抑制MCF-7 乳腺癌细胞增殖的作用,尤以萌发第3 天(芦丁与槲皮素含量比为0.92:1)时抑制效果最好,显示二者具有良好的协同抑制效果;苦荞芽粉乙醇提取物的抑制效果与槲皮素和芦丁标准品模拟样品抑制效果相似,表明苦荞芽粉乙醇提取物对MCF-7 细胞的生长起抑制作用的主要功效成分为槲皮素和芦丁。     

富平尖柿果皮色素的理化及功能特性

为了探索富平尖柿果皮色素的功能性及应用特性,本文采用溶剂提取纯化技术、光谱分析及体外抗氧化、抑菌、抑癌试验,研究了柿子皮色素的提取纯化、成分组成、理化特性及体外清除自由基、抑菌、对HepG2及MNK-45细胞体外增殖的影响。结果表明:富平尖柿果皮色素的提取率高达2.18%,色素中含有10种以上成分,其中β-胡萝卜素占52.31%,叶黄素占8.73%,玉米黄质占4.02%;光照、高温、氧化剂、Cu2+可导致柿子皮色素褪色,酸、Ca2+、Zn2+、Al3+可使柿子皮色素产生沉淀,还原剂和防腐剂对柿子皮色素有保护作用;柿子皮色素可清除DPPH·、·OH、ABTS+·,可螯合Fe2+,与V_C、β-胡萝卜素、叶黄素相比,抗氧化性能强弱依次为V_C>β-胡萝卜素>柿皮色素>叶黄素,柿子皮色素抗脂质过氧化能力随浓度增加而增强;柿子皮色素对沙门氏菌、金黄色葡萄球菌、大肠杆菌均有抑制作用,对李斯特菌、阪崎乳杆菌无抑制作用;柿皮色素对HepG2及MNK-45癌细胞体外增殖有一定抑制效果。富平尖柿果皮色素具有良好抗氧化、抑菌、抗癌细胞体外增殖性能,可作为天然功能性色素使用。     

叶黄素、玉米黄素分子结构修饰对抑制肿瘤细胞增殖活性的影响

目的:探讨叶黄素、玉米黄素的结构与抗肿瘤效果之间的关系。方法:以从玉米蛋白粉中分离、提取的叶黄素和玉米黄素为原料,通过化学合成的方法分别对其所携带的紫罗酮环上的羟基进行单、双乙酰化修饰,所合成的产物用紫外可见光扫描,液质联用,核磁共振等手段分子结构的鉴定;用MTT(噻唑蓝)的方法测定各叶黄素、玉米黄素结构被修饰前后抑制人口腔上皮细胞癌KB增殖活性的变化。结果:叶黄素、玉米黄素分子紫罗酮环上的羟基被乙酰基取代后,其抑制细胞增殖的活性有所降低。结论:叶黄素和玉米黄素分子结构中羟基取代基的存在对其调节肿瘤细胞的增殖能力有一定的贡献。     

Processed and prepared corn products as sources of lutein and zeaxanthin: compositional variation in the food chain

ABSTRACT:  Widely consumed by populations of all socioeconomic classes worldwide, corn is one of the few food sources of lutein and zeaxanthin. However, data on these carotenoids in processed corn and corn as eaten are lacking. Thus, the major carotenoids in the principal brands of processed corn (canned corn, corn meal, corn flour, corn flake) and in typical corn dishes (farofa, boiled corn, pamonha, curau, fried and boiled polenta) were determined. There was marked variation between processed products and between brands of the same product, but variation between lots of the same brand was small. Canned corn had the highest zeaxanthin (11.91 to 18.06 μg/g), β-cryptoxanthin (2.32 to 3.77 μg/g), and β-carotene (1.79 to 2.75 μg/g) contents. The corn flake breakfast cereal had the second highest amount of zeaxanthin (9.08 to 12.77 μg/g). Corn meal had the highest lutein (4.02 to 7.62 μg/g) level and also had good zeaxanthin content (6.13 to 11.39 μg/g), but drastic reduction of all carotenoids, especially zeaxanthin, occurred when it was toasted to farofa. Boiled corn also had lower carotenoid levels compared to the raw corn. The wide variations in carotenoid concentrations appeared to be due mainly to varietal differences in the carotenoid composition of raw materials and to losses during processing and preparation for consumption.     

三羟异黄酮对人乳腺癌细胞株MCF-7增殖的影响机制

研究了三羟异黄酮(geinstein，Gen)对乳腺癌细胞株MCF-7增殖的影响机制。结果发现Gen对MCF-7细胞生长有显著抑制作用，使细胞生长阻滞于G2／M期，并使cyclin B蛋白表达增加，且呈剂量．效应关系；对cyclin E蛋白表达无影响。Gen降低了bcl-2蛋白的表达，促进了bax蛋白的表达并且降低了bcl-2／bax比值。     

Evidence for a local effect of leptin in bovine mammary gland

On average, high-energy diets promoting body growth rates above 1 kg/d before puberty impair mammary development by 15 to 20% in cattle. We hypothesized that leptin, a protein produced by adipocytes, mediates the inhibitory effect of high-energy diets on mammary development. Therefore, our objectives were to determine the effect of leptin on mammary epithelial cell proliferation, and the distribution of mRNA for two leptin receptor isoforms in prepubertal bovine mammary glands and other peripheral tissues. Addition of leptin to culture media containing either 5 ng/ml of insulin-like growth factor-I (IGF-I) or 1% fetal bovine serum decreased DNA synthesis of a bovine mammary epithelial cell line (MAC-T) in a dose-dependent manner. The minimal doses of leptin that decreased IGF-I- and fetal bovine serum-stimulated cell proliferation were 64 and 1 ng/ml, respectively. In addition, we determined that MAC-T cells and isolated bovine mammary epithelial cells express the long form of leptin receptor (Ob-Rb) mRNA. Ob-Rb mRNA was detected in all bovine tissues examined. In contrast with reports on other species, mRNA expression of the short form of leptin receptor (Ob-Ra) was detected only in bovine liver, pituitary body, and spleen. These results support the concept that leptin mediates the inhibitory effect of high-energy diets on mammary development.     

Effect of acute stressors,adrenocorticotropic hormone administration,and cortisol release on milk yield,the expression of key genes,proliferation, and apoptosis in goat mammary epithelial cells

Cortisol is essential to milk synthesis; however, different acute stressors and the exogenous administration of adrenocorticotropic hormone (ACTH) decrease milk yield. Therefore, the effect of cortisol on milk yield and its influence on the survival of mammary epithelial cells have not been fully elucidated. In this context, the objective of this study was to evaluate the effect of cortisol on the expression of growth hormone receptor (GHR), insulin-like growth factor type 1 (IGF1), insulin-like growth factor type 1 receptor (IGF1R), insulin-like growth factor-binding protein 3 and 5 (IGFBP3 and IGFBP5), BAX, and BCL2 genes on the proliferation and apoptotic rates of mammary epithelial cells, and on milk yield in Saanen goats. In the present study, 3 experiments were conducted: (1) comparing the in vivo effects of first milking, vaccination, vermifugation, preventive hoof trimming, and the administration of ACTH or a placebo on cortisol release in dairy goats; (2) studying the in vivo effects of immediate increases in cortisol on the mammary gland of lactating goats; and (3) studying the in vitro effects of a prolonged increase in cortisol on mammary epithelial cells obtained from lactating goats. Cortisol release by goats increased significantly after ACTH administration compared with that observed after a placebo, and the cortisol profiles after first milking, vaccination, vermifugation, hoof trimming, and ACTH administration were similar. However, there was no effect of the immediate increase in cortisol in vivo on IGF-1 release, milk yield, milk quality, or the apoptosis and proliferation rates, nor was there any effect on the expression of the target genes. Furthermore, no interaction was observed between IGF-1 and cortisol in either the in vivo or in vitro experiments. However, the addition of cortisol in vitro significantly increased the expression of the GHR and IGF1R genes, which stimulate cell proliferation, and the BAX gene, which causes apoptosis. These contrasting results can explain why cortisol did not change the rates of proliferation or apoptosis in epithelial cells. Indeed, cortisol supplementation in vitro did not change the number or apoptotic rate of epithelial cells over the course of 5 d. Finally, further studies must be performed to understand the effect of cortisol on the expression of the GHR, IGF1R, and BAX genes by epithelial cells and the roles of these genes in milk synthesis during early lactation.     

柠檬苦素类化合物对人乳腺癌细胞(MCF-7)的生长抑制及细胞周期动力学的影响

为了探讨柠檬苦素类似物对乳腺癌细胞MCF-7生长抑制和对细胞周期的影响,应用MTT法和流式细胞仪检测癌细胞株生长和细胞周期.结果显示柠檬苦素类似物能明显抑制MCF-7的生长,抑制率高于70%,并随作用时间和剂量增加其效果增强;柠檬苦素可以影响细胞周期G     

雌马酚对人乳腺癌MCF-7细胞生长的影响

目的：观察雌马酚在不同浓度水平下对雌激素依赖阳性人乳腺癌MCF-7细胞生长的影响。方法：采用MTT法检测细胞增殖,流式细胞术分析细胞周期分布情况。结果：MCF-7细胞经去雌激素处理以后,与对照组相比,雌马酚在10-6～10-5mol/L时可显著抑制细胞增殖,使S期细胞增多,其抑制作用可被雌激素受体特异性抑制剂ICI-182780阻断。结论：雌马酚对人乳腺癌细胞MCF-7的细胞增殖具有抑制作用,可干扰DNA的复制,具有一定的雌激素样作用,且其抑制作用可能是通过雌激素受体（ER）介导的。     

Effect of heat stress during the dry period on mammary gland development

Heat stress during the dry period negatively affects hepatic metabolism and cellular immune function during the transition period, and milk production in the subsequent lactation. However, the cellular mechanisms involved in the depressed mammary gland function remain unknown. The objective of the present study was to determine the effect of heat stress during the dry period on various indices of mammary gland development of multiparous cows. Cows were dried off approximately 46 d before expected calving and randomly assigned to 2 treatments, heat stress (HT, n = 15) or cooling (CL, n = 14), based on mature equivalent milk production. Cows in the CL treatment were provided with sprinklers and fans that came on when ambient temperatures reached 21.1°C, whereas HT cows were housed in the same barn without fans and sprinklers. After parturition, all cows were housed in a freestall barn with cooling. Rectal temperatures were measured twice daily (0730 and 1430 h) and respiration rates recorded at 1500 h on a Monday-Wednesday-Friday schedule from dry off to calving. Milk yield and composition were recorded daily up to 280 d in milk. Daily dry matter intake was measured from dry off to 42 d relative to calving. Mammary biopsies were collected at dry off, −20, 2, and 20 d relative to calving from a subset of cows (HT, n = 7; CL, n = 7). Labeling with Ki67 antigen and terminal deoxynucleotidyl transferase deoxyuridine triphosphate nick-end labeling were used to evaluate mammary cell proliferation and apoptosis, respectively. The average temperature-humidity index during the dry period was 76.6 and not different between treatments. Heat-stressed cows had higher rectal temperatures in the morning (38.8 vs. 38.6°C) and afternoon (39.4 vs. 39.0°C), greater respiration rates (78.4 vs. 45.6 breath/min), and decreased dry matter intake (8.9 vs. 10.6 kg/d) when dry compared with CL cows. Relative to HT cows, CL cows had greater milk production (28.9 vs. 33.9 kg/d), lower milk protein concentration (3.01 vs. 2.87%), and tended to have lower somatic cell score (3.35 vs. 2.94) through 280 d in milk. Heat stress during the dry period decreased mammary cell proliferation rate (1.0 vs. 3.3%) at −20 d relative to calving compared with CL cows. Mammary cell apoptosis was not affected by prepartum heat stress. We conclude that heat stress during the dry period compromises mammary gland development before parturition, which decreases milk yield in the next lactation.