富硒菊芋多糖的提取及其体外抗氧化活性研究

为了研究富硒菊芋多糖的提取工艺及其体外抗氧化活性,本研究以亚硒酸钠为硒源,采用盆栽施硒法对菊芋进行富硒培养;利用超声辅助法,在单因素试验的基础上,应用响应面法优化富硒菊芋多糖提取的影响因素（超声时间、超声功率和液料比）;在此基础上,探究富硒前后菊芋多糖对羟自由基(·OH)、1,1-二苯基-2-三硝基苯肼(1,1-diphenyl-2-trinitrophenylhydrazine, DPPH)自由基及超氧阴离子自由基(O^2-·)清除率的影响。结果表明：菊芋能够吸收无机硒将其转化为有机硒;富硒菊芋多糖的最佳提取条件为超声时间(60 min)、超声功率(450 W)和液料比[25:1(mL/g)],硒多糖提取率最高(13.52%);富硒菊芋多糖(Se-Inulin)和普通菊糖(Inulin)对羟基自由基、DPPH自由基及超氧自由基的清除活性均呈现出良好的量效关系,最大清除率可分别达到80.34%、89.19%与88.54%,Se-Inulin的抗氧化活性优于Inulin。本研究为富硒菊芋产品的开发提供了一定的理论依据。     

Fish Oil,Se Yeast,and Micronutrient-Enriched Nutrition as Adjuvant Treatment during Target Therapy in a Murine Model of Lung Cancer

Despite the effectiveness of primary treatment modalities for cancer, the side effects of treatments, medication resistance, and the deterioration of cachexia after disease progression lead to poor prognosis. A supportive treatment modality to overcome these limitations would be considered a major breakthrough. Here, we used two different target drugs to demonstrate whether a nutraceutical formula (fish oil, Se yeast, and micronutrient-enriched nutrition; NuF) can interfere with cancer cachexia and improve drug efficacy. After Lewis lung cancer (LLC) tumor injection, the C57BL/6 mice were orally administered targeted therapy drugs Iressa and Sutent alone or combined with NuF for 27 days. Sutent administration effectively inhibited tumor size but increased the number of lung metastases in the long term. Sutent combined with NuF had no significant difference in tumor weight and metastasis compare with Sutent alone. However, NuF slightly attenuated metastases number in lung may via mesenchymal marker N-cadherin suppression. NuF otherwise increased epithelial-like marker E-cadherin expression and induce NO-mediated intrinsic apoptotic pathway in tumor cells, thereby strengthening the ability of the targeted therapy drug Iressa for inhibiting tumor progression. Our results demonstrate that NuF can promote the anticancer effect of lung cancer to targeted therapy, especially in Iressa, by inhibiting HIF-1α and epithelial-mesenchymal transition (EMT) and inducing the apoptosis of lung cancer cells. Furthermore, NuF attenuates cancer-related cachectic symptoms by inhibiting systemic oxidative stress.     

日粮中缺硒对鸡空肠肥大细胞组织化学和超微结构的影响

为探讨硒缺乏对鸡空肠中肥大细胞(MC)的形态学和超微结构的影响,将10只鸡随机分成低硒试验组(饲喂低硒日粮0.032 mg/kg)和正常对照组,在75日龄时断头处死立即取出空肠,进行甲苯胺蓝、长时间甲苯胺蓝、阿利新蓝-藏花红染色、阿利新蓝-高碘雪夫氏反应和醛品红-阿利新蓝5种染色并进行透射电镜观察。结果显示,采用不同染色方法所获得的MC数量、大小、形态、颜色及颗粒的黏多糖成分均不相同。电镜下,MC细胞胞浆内充盈大量的特征性颗粒,颗粒内容物呈均质状,电子密度高低不等,核圆形或椭圆形,胞质中可见高尔基复合体和较多的线粒体;试验组可见MC数量显著增加并与变性细胞紧密相邻,异染色质增多,核偏位或固缩,胞质稀疏,同时可见MC内颗粒内容物释放后的空隙或空泡。因此,组化染色提示肥大细胞存在不同亚型;试验组MC数量明显增加,这提示MC是重要的免疫细胞之一,在机体的免疫调节中发挥着重要的作用。     

富硒链霉菌wh63的鉴定及富硒特性研究

富硒链霉菌wh63可在平板硒浓度为100 mg/L时生长良好。低浓度的硒元素可以促进菌株生长,高浓度则会抑制菌株的生长,硒添加量为0.5和1.0 mg/L的wh63菌株生物量比对照分别提高12%和8%。通过显微形态学观察,wh63菌株孢子丝卷曲,孢子表面光滑;在高氏1号培养基上,气生菌丝为白色,后期颜色会变深。结合16S r DNA序列分析鉴定,发现其与唐德链霉菌(Streptomyces tendae)的同源性最高,为99%,且生理生化特性一致,初步鉴定wh63菌株为链霉菌属(Streptomyces)。通过菌落形态观察,结合SEM(扫描电镜)和IR(红外光谱)分析,发现链霉菌wh63可以将无机硒转化为红色单质硒,红色单质硒附着在富硒链霉菌wh63菌体表面。     

外源硒对油葵籽仁含油率及脂肪酸含量的影响

为了解盐碱地油用向日葵(油葵)施硒效应,通过大田试验研究外源硒对盐碱地油葵(矮大头567DW和美国超级矮大盘)含油率及脂肪酸含量的影响。结果表明:土施硒肥对矮大头567DW籽仁亚油酸、油酸、廿碳烯酸和棕榈酸含量无明显影响,硒肥用量200~300g/hm2时显著提高籽仁含油率,降低籽仁芥酸含量;400g/hm2时增加籽仁饱和脂肪酸硬脂酸、山嵛酸和廿碳烷酸含量;土施硒肥对美国超级矮大盘的籽仁含油率、亚油酸、油酸、廿碳烯酸、芥酸、棕榈酸、硬脂酸和廿碳烷酸含量无明显影响,硒肥用量400g/hm2时提高山嵛酸含量。叶面喷施硒肥条件下,矮大头567DW籽仁亚油酸、油酸、廿碳烯酸、硬脂酸、山嵛酸和廿碳烷酸均无明显影响,叶面喷施60g/hm2硒肥时增加籽仁芥酸、棕榈酸含量,降低籽仁含油率;叶面喷施硒肥对美国超级矮大盘的籽仁含油率、亚油酸、油酸、棕榈酸、硬脂酸、山嵛酸和廿碳烷酸均无明显影响,叶面喷施60g/hm2硒肥显著提高其籽仁芥酸含量。综合考虑2个品种的含油率和脂肪酸变化,在盐碱地油葵栽培中,土施200~300g/hm2或叶面喷施20~40g/hm2硒肥对提高矮大头567DW和美国超级矮大盘籽仁含油率和脂肪酸效果较佳。     

红小豆富硒栽培研究

[目的]研究红小豆的富硒能力,提升红小豆的品质。[方法]对红小豆进行富硒栽培试验,对比红小豆的经济性状、植株免疫力、产量、产品总含硒量等。[结果]随着外源硒肥施用量的增加,红小豆的含硒量升高;硒肥对红小豆经济性状、免疫力无明显影响;随着硒肥用量增加,红小豆产量呈现递减的趋势。[结论]红小豆具有吸收和转化硒元素的功能,适量的硒肥能促进红小豆的增产增收。     

长期施肥对土壤中硒的累积及其生物有效性的影响

Continuous applications of organic and inorganic fertilizers can affect soil and food quality with respect to selenium(Se) concentrations.A long-term(over 20 years) experimental field study,started in 1989,was conducted to investigate the changes in soil Se fractions and its uptake by crops,as affected by different fertilizer practices,in the North China Plain with an annual crop rotation of winter wheat and summer maize.The long-term experiment was arranged in a complete randomized block design consisting of 4replications with 7 fertilizer treatments:1) organic compost(OC),2) half organic compost plus half N-P-K chemical fertilizers(OC+ NPK),3) N-P-K fertilizers(NPK),4) N-P fertilizers(NP),5) P-K fertilizers(PK),6) N-K fertilizers(NK),and 7) an un-amended control.Soil samples from the surface(20 cm) were collected in 1989,1994,1999,2004 and 2009 to characterize Se and other soil properties.In 2009,the average soil Se concentrations in the treatments(149 ± 8 μg kg~(-1)) were higher than those in the soil samples collected in 1989 at the beginning of the experiment(112 ± 4 μg kg~(-1)),and decreased in the order of OC OC + NPK NPK≈NP PK ≈NK control.Sequential extraction showed the oxidizable fraction(50.06%± 3.94%) was the dominant form of Se in the soil,followed by the residual fraction(24.12%± 2.89%),exchangeable fraction(15.09%± 4.34%) and Fe-Mn oxides fraction(10.73%± 4.04%).With an increase of soil K,the exchangeable Se concentrations in the soil increased.The Se concentrations in the soil tillage layer(0-20 cm) were mainly related to soil organic carbon(SOC),although different contributions came from atmospheric deposition,irrigation and fertilizers.With the accumulation of SOC,the uptakes of soil Se by two crops were inhibited.For the OC and OC + NPK treatments,Se concentrations in wheat grains were lower than the critical standard of Se in stable food(100 μg kg~(-1)).Additionally,Se concentrations in grains were also decreased by the deficiencies of major soil nutrients,especially P.     

叶用莴苣富硒效果影响的研究

对‘射手101’、‘大像生一号’、‘美国大速生’3种叶用莴苣的富硒效果进行比较。分别采用叶面喷施浓度梯度为7.5、15.0、22.5 g/hm2的硒酸钠与亚硒酸钠溶液,进行1次或2次叶面喷施,利用原子荧光光谱仪标准曲线法测量硒含量。结果显示：不同浓度的2种硒源均可以提高3种叶用莴苣含硒量。其中,浓度为22.5 g/hm2的亚硒酸钠富硒效果最好。喷施1次,‘射手101’效果最佳,含硒量为(11.33±1.52753) μg/100 g。喷施2次,‘大像生一号’效果最佳,含硒量为(14.33±0.5774) μg/100 g,约为喷施1次时含硒量(4.87±0.3215) μg/100 g的3倍。     

硒对异养小球藻生长及品质的影响

从可溶性糖、蛋白质、色素、Vc含量以及生物量等方面,探讨了不同浓度硒处理对异养小球藻生长及品质的影响。结果表明,硒对小球藻生长过程中及体内主要化学物质的影响显著。随着硒浓度的增加,可溶性糖、Vc、叶绿素b的含量均呈显著下降趋势,而生物量、蛋白质、叶绿素a和类胡萝卜素含量则呈先升后降趋势。当硒浓度增加至25 mg/L时,小球藻的生长即受到明显的抑制,各种化学物质的含量均显著下降。表明一定量的硒有利于异养小球藻的生长及其品质的改善。     

烤烟苗期含硒量和根际硒形态的研究

以烤烟品种NC89为试材, 通过天然含硒和低硒土施硒处理的盆栽试验,对烤烟苗期含硒量和根际-根外土壤硒的存在形态进行了分析。结果表明,烤烟苗期根系含硒量高于地上部,并随天然含硒和施硒量的增加而增加,且与施硒量呈极显著的正相关。天然含硒土中,残渣态硒（Res-Se）占2/3以上,而低硒土施硒下,KH₂PO₄-Se所占比例最大。无论天然含硒土还是施硒低硒土,水溶性硒（H₂SO₄-Se）所占比例均不到1%,而根际土壤总硒、KH₂PO₄-Se和NH₃·H₂O-Se的含量均高于根外土。土壤施硒处理的NH₃·H₂O-Se占总硒的比例高于根外土壤,而Res-Se所占比例低于根外土。由此可见,烤烟能够富集土壤中的硒,天然含硒土和低硒土施硒的硒形态分布不同,施硒土壤硒的有效性高于天然含硒土,烤烟根际硒的有效性高于根外土,烤烟根际通过促进有机态硒的形成而减少土壤矿物对硒的固定来提高土壤施硒的有效性。