含重组人乳铁蛋白乳粉蛋白质营养学评价

目的评价牛乳腺生物反应器表达的重组人乳蛋白乳粉蛋白质的营养价值。方法选用100只清洁级刚断乳(出生后20~23 d)SD大鼠(雌、雄各半),按性别、体质量随机分为5组:重组人乳蛋白乳粉组、普通乳粉组、酪蛋白乳粉组、牛乳铁蛋白乳粉组、重组人乳铁蛋白乳粉组,分别喂饲相应饲料28 d,观察大鼠的进食量、体质量,测定血常规、血生化情况,试验末期处死动物,称量脏器重量并对脏器进行病理学检查,计算蛋白功效比和校正蛋白功效比,对氨基酸评分。结果重组人乳铁蛋白乳粉雄性动物组总体蛋白功效比值差异有统计学意义(P0.05),但重组人乳铁蛋白乳粉组雄性和其他对照组差异无统计学意义(P0.05)。雌性动物重组人乳铁蛋白乳粉组和其他对照组蛋白功效比值差异无统计学意义(P0.05)。结论重组人乳铁蛋白乳粉的蛋白功效和其他组相比并无较大区别,氨基酸评分结果显示苯丙氨酸和酪氨酸为第一限制氨基酸,与普通乳粉一样。     

重组人乳铁蛋白对大鼠生长发育作用的实验研究

目的 研究从转基因牛乳中分离纯化的重组人乳铁蛋白是否具有促进动物生长发育的作用.方法 给大鼠灌胃重组人乳铁蛋白共8周,设低、中、高3个剂量组(0.375,0.75和2.25 g/kg BW·d)以水为对照组.检测指标包括动物体重、身长、摄食童和食物利用率.结果 高剂量组体重、身长和食物利用率指标均显著优于对照组,低、中剂量组的体格发育指标较对照组有轻度改善.结论 在本研究条件下,重组人乳铁蛋白具有促进大鼠生长发育的作用.     

乳铁蛋白活性多肽的抑菌性能

概述了乳铁蛋白活性多肽的结构、制备方法、抑菌谱、抑菌机理及抑菌活性的影响因素.     

乳铁蛋白研究现状

文章综述了乳铁蛋白最新研究成果，主要包括乳铁蛋白分子结构、分离提取方法、生物学功能、乳铁蛋白基因及重组乳铁蛋白的研究现状，介绍了乳铁蛋白及其活性多肽（抗菌肽、促进细胞生长肽）的抗微生物（细菌、病毒、真菌）作用、促进细胞生长作用、免疫增强作用、抗氧化及抗肿瘤作用、参与铁代谢过程等作用，对铁蛋白在临床及食品工业中的应用作了分析。     

乳铁蛋白的生理功能

叙述了乳铁蛋白具有促铁吸收,调节免疫,抑菌,抗病毒,阻断氧自由基,避免刺激肠胃和促进双歧杆菌生长等功能,上述功能在乳品（特别是婴幼儿食品）加工中具有广泛的应用。     

牛乳中乳铁蛋白的纯化和抗菌活性研究

采用凝胶过滤层析和离子交换法层析分离纯化乳铁蛋白,通过SDS-PAGE和IEF-PAGE鉴定所得样品;同时利用抗菌实验(滤纸片法)进行样品的抗菌活性研究,并研究了乳铁蛋白分离纯化过程中抗菌活性的变化。结果表明,离子交换层析纯化乳铁蛋白的效果优于凝胶过滤层析,抗菌活性证实乳铁蛋白样品具有广谱抗菌作用,以蜡状芽孢杆菌为指示菌时,比活为3077.3AU/mg(试管法),纯化倍数提高了20.2倍。     

牛乳中乳铁蛋白的纯化和抗菌活性研究

采用凝胶过滤层析和离子交换法层析分离纯化乳铁蛋白,通过SDS-PAGE和IEF-PAGE鉴定所得样品;同时利用抗菌实验（滤纸片法）进行样品的抗菌活性研究,并研究了乳铁蛋白分离纯化过程中抗菌活性的变化。结果表明,离子交换层析纯化乳铁蛋白的效果优于凝胶过滤层析,抗菌活性证实乳铁蛋白样品具有广谱抗菌作用,以蜡状芽孢杆菌为指示菌时,比活为3077.3AU/mg（试管法）,纯化倍数提高了20.2倍。      

牛乳中乳铁蛋白的分离纯化研究

牛乳经酸沉淀除酪蛋白后,通过超滤、离子交换法分离纯化得到乳铁蛋白,利用考马斯亮蓝、SDS-PAGE电泳定性定量检测。结果表明:每毫升牛乳能提取乳铁蛋白0.22mg,纯度为95%。     

酶解牛乳铁蛋白制备乳铁素 B的酶解条件研究

乳铁素B是牛乳铁蛋白经胃蛋白酶酶解后所得到的最重要的抗菌肽，乳铁蛋白酶解生成乳铁素后抗菌活性大大增强。通过正交试验确立了牛乳铁蛋白酶解制备乳铁素B的最佳条件，指出在底物质量浓度为50g／L，酶与底物质量浓度比为1：30(质量比)，酶解时间为60min时所得的乳铁素质量浓度及活性较好。     

牛乳中乳铁蛋白含量变化规律的研究

为了解牛乳中乳铁蛋白随着季节、饲养环境而变化的规律,利用毛细管电泳法分别检测从牧场、小区、奶户采集牛乳样中乳铁蛋白,周期为1年.结果得出,牧场牛乳含量高于小区,奶户牛乳中LF最低,1月份牧场牛乳LF含量达最高,为0.16mg/mg,而奶户牛乳中LF最低,达0.08mg/mg.9月份牧场、小区和奶户牛乳LF含量达最低,分别达0.03、0.05和0.06 mg/mL.结果表明随着管理水平的提高和气候的变冷,牛乳中乳铁蛋白含量逐渐升高,这将有利于改进饲养管理条件提供有效的理论参考.     

重组人乳铁蛋白致敏性的初步研究

目的 初步评价牛乳腺生物反应器表达的重组人乳铁蛋白(rhLf)的致敏性.方法 通过生物信息学分析和消化稳定性试验了解rhLf致敏的可能性.结果 生物信息学分析显示rhLf与已知致敏原乳转铁蛋白和卵转铁蛋白有序列同源性,与Asp f2、Ole e 10和Ole e9存在结构相似性.消化稳定性试验显示rhLf在胃液中易被消化成小片段,在肠液中不易被消化.结论 rhLf具有一定的潜在致敏可能性.     

栎皮酮的抗氧化性能研究

栎皮酮是一种天然的食品抗氧化剂,通过诱导时间实验与烘箱贮藏实验测定了栎皮酮的抗氧化性能.研究发现,栎皮酮能显著延长花生油、棕榈油和猪板油的诱导时间,同时能提高这3种油样的贮藏稳定性.栎皮酮分别与BHT、TBHQ复配使用时,其协同作用并不明显.     

蜂胶乙醇提取物抗氧化性能研究

以核桃仁为试验材料 ,研究蜂胶乙醇提取物的抗氧化作用 ,结果表明0 05 %的蜂胶抗氧化能力是0 02 %BHT的2倍。     

香辛料抗氧化活性的研究现状

香辛料有很多功能，而抗氧化活性是其重要功能之一。本文论述了30种香辛料的抗氧化活性和一些香辛料对高含DHA鱼油的抗氧化抑制效果，并介绍了从一些香辛料中分离出的具有高活性的抗氧化性物质。     

花脸香蘑抗氧化作用的研究

目的:研究花脸蘑提取物的体外抗氧化作用。方法:利用比色法测定花脸蘑乙醇提取物的总抗氧化能力、对羟基自由基(·OH)和二苯基苦味酰基苯肼(DPPH)的清除能力以及H2O2诱导的肝损伤组织中超氧化物歧化酶(SOD)、谷胱甘肽过氧化物酶(GSH-Px)、过氧化氢酶(CAT)的活性和丙二醛(MDA)的含量。结果:总抗氧化能力与花脸蘑提取物的浓度呈正相关,花脸蘑提取物具有清除·OH和DPPH自由基能力,提高肝组织SOD、GSH-Px、CAT活性并抑制肝组织MDA的生成。结论:花脸蘑提取物具有体外抗氧化作用。     

Detection of recombinant human lactoferrin and lysozyme produced in a bitransgenic cow

Lactoferrin and lysozyme are 2 glycoproteins with great antimicrobial activity, being part of the nonspecific defensive system of human milk, though their use in commercial products is difficult because human milk is a limited source. Therefore, many investigations have been carried out to produce those proteins in biological systems, such as bacteria, yeasts, or plants. Mammals seem to be more suitable as expression systems for human proteins, however, especially for those that are glycosylated. In the present study, we developed a bicistronic commercial vector containing a goat β-casein promoter and an internal ribosome entry site fragment between the human lactoferrin and human lysozyme genes to allow the introduction of both genes into bovine adult fibroblasts in a single transfection. Embryos were obtained by somatic cell nuclear transfer, and, after 6 transferences to recipients, 3 pregnancies and 1 viable bitransgenic calf were obtained. The presence of the vector was confirmed by fluorescent in situ hybridization of skin cells. At 13 mo of life and after artificial induction of lactation, both recombinant proteins were found in the colostrum and milk of the bitransgenic calf. Human lactoferrin concentration in the colostrum was 0.0098 mg/mL and that in milk was 0.011 mg/mL; human lysozyme concentration in the colostrum was 0.0022 mg/mL and that in milk was 0.0024 mg/mL. The molar concentration of both human proteins revealed no differences in protein production of the internal ribosome entry site upstream and downstream protein. The enzymatic activity of lysozyme in the transgenic milk was comparable to that of human milk, being 6 and 10 times higher than that of bovine lysozyme present in milk. This work represents an important step to obtain multiple proteins or enhance single protein production by using animal pharming and fewer regulatory and antibiotic-resistant foreign sequences, allowing the design of humanized milk with added biological value for newborn nutrition and development. Transgenic animals can offer a unique opportunity to the dairy industry, providing starting materials suitable to develop specific products with high added value.     

熊果酸抗氧化性能的研究

目的:研究熊果酸的抗氧化性能.方法:采用邻苯三酚自氧化法,Feton体系法测定熊果酸对超氧阴离子和羟自由基的清除能力.从而探求熊果酸的抗氧化性能.结果:实验表明熊果酸时超氧阴离子和羟自由基有明显的清除作用,熊果酸超氧阴离子的最高清除率可达88.42%,但是清除作用弱于同浓度下的Vc.熊果酸对羟自由基的清除作用最高可达86.35%,并且强于同浓度下的甘露醇.结论:熊果酸具有明显的抗氧化性.     

Antimicrobial activity of recombinant human lactoferrin from <Emphasis Type="Italic">Aspergillus awamori</Emphasis>, human milk lactoferrin and their hydrolysates

The antibacterial activity of human lactoferrin from milk (hLF), recombinant human lactoferrin from Aspergillus awamori (rhLF) and their hydrolysates obtained with pepsin was investigated against Escherichia coli O157:H7, Salmonella Enteritidis and Listeria monocytogenes. The minimum inhibitory concentrations (MIC) and the minimum bactericidal concentrations (MBC) were determined for all the bacteria and the proteins assayed. Taking into account the MICs found for both lactoferrins studied, we can say that they behave very similarly, except for L. monocytogenes for which rhLF was more active. We studied the effect that heat treatments exerted on the antibacterial activity of the two types of lactoferrin and the only heat treatment that had a negative effect on that activity was 85 °C for 10 min. The activity of hLF and rhLF in UHT milk and whey against E. coli O157:H7 and L. monocytogenes, was also assayed. Our results showed a reduction in the number of viable cells for both microorganisms when were incubated with rhLF or hLF, but this decrease was lower than in broth media.     

Impact of the Maillard reaction on the antioxidant capacity of bovine lactoferrin

Studies raise the notion that the Maillard reaction (MR) may be harnessed to modify the antioxidant capacity of alimentary proteins. However, little is known about the impact of MR on bioactive proteins. Glucose and fructose were used as model moieties reacting with lactoferrin (LF). UV absorbance and SDS–PAGE analyses were used to monitor MR progression during 36 h of mild thermal processing (60 °C, 79% RH). FTIR and CD did not reveal changes in LF structure; However, dynamic light scattering showed MR increased mean particle sizes and sample turbidity at 3 < pH < 10. DPPH and FRAP antioxidant assays showed marked increases in antioxidant capacity of Maillard conjugates as a function of reaction time (12 and 36 h), protein:monosaccharide mole ratio (1:1 or 1:3) and moiety type, compared to unprocessed LF. Overall, a link between conjugates’ antioxidant capacity and processing parameters is described to enable future attempts to enhance LF functionality in foods containing carbohydrates.     

维康素片剂抗氧化作用研究

主要研究维康素片剂的抗氧化性能.试验建立293T细胞的体外氧化损伤保护模型,应用MTT法测定细胞活性,流式细胞仪检测法检测凋亡和死亡情况,采用50 μmol/L的VE作为对照.结果显示维康素片剂对H2O2引起细胞损伤有很好的保护作用.