牛乳脂肪球粒径研究进展

乳中脂肪主要以乳脂肪球（milk fat globule，MFG）形式从哺乳动物的乳腺中分泌到乳中，MFG粒径从?0.2 μm到15.0 μm不等，不同粒径MFG影响新生儿的健康及乳制品的理化特性。MFG粒径主要由乳腺上皮细胞中的?脂滴调控，脂滴大小的调控因素包括细胞内甘油三酯水平及其合成与水解过程中参与的酶、膜磷脂、脂滴融合等。本文主要综述MFG的合成和结构、MFG粒径对牛乳营养及乳制品加工的影响、脂滴融合对MFG粒径的调控，为?MFG粒径的应用提供参考。     

乳脂球膜蛋白的研究进展

乳脂球膜蛋白是乳腺在泌乳时包被在脂肪滴外的膜蛋白。乳脂肪球膜（milk fat globule membrane,MFGM）是磷脂、鞘脂和多种蛋白质组成的3层膜结构。乳脂球膜蛋白包含100余种蛋白质,含量最丰富的8种蛋白质为黏液素1、黄嘌呤氧化还原酶、黏液素15、CD36、嗜乳脂蛋白、乳凝集素、脂肪分化相关蛋白和脂肪酸结合蛋白。乳脂球膜蛋白已被证明具有丰富的开发利用价值,包括：反映奶牛母体的生理状态;作为幼体的营养和免疫来源,会影响犊牛的发育和母源抗体;会影响人和动物的免疫调节和体质,未来可能应用于疾病的治疗。作者介绍了乳脂球膜蛋白的来源、组成及一种新建立的乳脂球膜蛋白结构,阐述了几个主要蛋白的生理特性及乳脂球膜蛋白的研究进展,并对未来的研究方向提出建议。     

黄嘌呤氧化还原酶与乳脂肪滴分泌

黄嘌呤氧化还原酶(XOR)是黄素钼蛋白家族的一员,XOR在乳中含量最为丰富,作为乳中的一种主要蛋白酶,越来越引起人们的兴趣。本文描述了XOR的分子结构及表达调控,XOR的组织分布及细胞定位。近年来发现,XOR能够通过与脂肪滴结合蛋白(ADPH)和嗜乳脂蛋白(B tn)的相互作用,在乳腺分泌乳脂肪滴的过程中起到重要的调节作用。对XOR的具体作用机制进行深入研究,有利于弄清乳腺发育和乳汁分泌机理以及对一些乳腺疾病的预防和治疗。     

牛初乳与牛常乳中乳脂肪球膜蛋白质的组成及功能的对比研究

利用十二烷基硫酸钠-聚丙烯酰胺凝胶电泳(sodium dodecyl sulfate polyacrylamide gel electropheresis,SDS-PAGE)将牛初乳与牛常乳中乳脂肪球膜蛋白质的组成部分进行分离鉴定,发现牛初乳与牛常乳中乳脂肪球膜蛋白质的组成存在较大的差异,且在牛初乳中鉴定出628种乳脂肪球膜蛋白质,牛常乳中鉴定出487种乳脂肪球膜蛋白质.由基因本体(gene ontology,GO)功能注释分析发现,在生物过程中生物调控作用是牛初乳和牛常乳中乳脂肪球膜的主要生物过程.在分子功能上,牛初乳的乳脂肪球膜蛋白质的绑定作用大于牛常乳.在细胞组成上,牛初乳乳脂肪球膜蛋白质参与细胞外区域远远大于牛常乳.通过京都基因与基因组百科全书系统(Kyoto Encyclopedia of Genes and Genomes,KEGG)代谢通路分析可知,牛初乳和牛常乳乳脂肪球膜蛋白质参与的代谢途径不同,表明牛初乳在日后的生产加工中更具有利用价值.     

荷斯坦奶牛乳与牦牛乳的差异蛋白质组学分析

本试验利用蛋白质组学方法分析荷斯坦奶牛乳与牦牛乳乳清与乳脂肪球膜中的差异蛋白,比较功能差异,为开发不同品种牛乳提供帮助。通过离心法分离荷斯坦奶牛乳与牦牛乳的乳清与乳脂,分别提取蛋白,通过串联质谱标签（TMT）法进行蛋白质定性与定量分析,得到差异蛋白;对差异蛋白进行GO功能注释、KEGG代谢通路、蛋白质互作（PPI）等生物信息学分析。结果显示：牦牛乳的乳脂、乳蛋白、乳糖、总固形物和非乳脂固形物含量均显著高于荷斯坦奶牛乳（P<0.05）。在2种牛乳乳清中共鉴定到可信蛋白641种,在乳脂肪球膜中共鉴定到可信蛋白543种;在乳清中筛选出差异蛋白268种,其中牦牛乳比荷斯坦奶牛乳上调70种,下调198种;在乳脂肪球膜中筛选出差异蛋白267种,其中牦牛乳比荷斯坦奶牛乳上调68种,下调199种。GO功能注释及富集分析表明2种牛乳的乳清和乳脂肪球膜差异蛋白均主要富集在细胞外空间、小分子结合和免疫反应等方面。KEGG注释及富集分析表明2种牛乳的乳清和乳脂肪球膜差异蛋白主要富集在金黄色葡萄球菌感染、补体与凝血级联等通路。差异蛋白互作网络分析发现2种牛乳的乳清差异蛋白中甘油醛-3-磷酸脱氢酶（GAPD...     

乳脂肪球膜组成及分离提取技术研究进展

乳中的脂肪以脂肪球的形态存在，被3 层膜包裹，称之为乳脂肪球膜（milk fat globule membrane，MFGM）。由于MFGM生物学功能和乳化潜力的相关报道，MFGM引发了广泛研究。本文综述MFGM的结构、组成、分离提取方法以及不同分离提取方法中工艺参数变化对MFGM组成的影响。     

人初乳与牛初乳中乳脂肪球膜蛋白质组成的对比研究

通过十二烷基硫酸钠-聚丙烯酰氨凝胶电泳(sodium dodecyl sulfate polyacrylamide gel electrophoresis,SDS-PAGE)将人初乳与牛初乳中乳脂肪球膜蛋白进行分离并结合液-质联用技术鉴定,在人初乳乳脂肪球膜蛋白中鉴定出l 076种蛋白质,牛初乳乳脂肪球膜蛋白中鉴定出682种蛋白质,其中人初乳中有757种特异性表达蛋白质,牛初乳中有363种特异性表达蛋白质,两者有319种相同表达蛋白质.通过基因本体(gene ontolpgy,GO)功能注释分析发现,人初乳乳脂肪球膜蛋白在生物过程中发挥的作用高于牛初乳,尤其表现在细胞组成组织功能上;在分子功能上,人初乳乳脂肪球膜蛋白主要体现在结合作用方面:在细胞组成上,与牛初乳乳脂肪球膜蛋白相比人初乳乳脂肪球膜参与的细胞组成均较多,其中在细胞胞内区的组成上参与最多.通过京都基因与基因组百科全书系统(Kyoto Encyclopedia of Genes and Genomes,KEGG)代谢通路分析可知,人初乳乳脂肪球膜蛋白中有15种蛋白参与了与消化吸收相关的KEGG通路-酶酵解.     

共轭亚油酸诱导的奶牛低脂乳症中脂肪球膜甘油磷脂的组成差异分析

旨在分析共轭亚油酸(CLA)诱导奶牛低脂乳症对牛乳脂肪球膜甘油磷脂含量的影响.选取体况相近、泌乳中期的10头荷斯坦奶牛进行自身前后对照设计,试验期12 d,第1天至第6天每头牛饲喂基础日粮+CLA 400 g·d-1,第7天至第12天恢复为饲喂基础日粮,每天记录产奶量及采食量,分析乳成分及乳脂肪球(MFG)粒径参数,对...     

乳脂肪球膜的研究进展

脂肪以液滴或球状形态稳定分散于乳中。这些脂肪球被一层薄膜包裹,称为乳脂肪球膜(MFGM)。MFGM是由磷脂、鞘脂及多种蛋白质组成的复杂三层结构。奶牛的生理状况、泌乳期、挤奶操作、加工处理等,都会对MFGM产生影响。此外,MFGM中的蛋白质和脂质组分也被证明具有特殊营养价值。本文总结了近年来关于MFGM的研究,旨在描述MFGM的组成及结构、影响因素及其营养价值,并对未来的研究方向提出建议。     

影响Mozzarella干酪凝胶体系构建的乳脂肪特性的研究进展

本文概括了凝乳、拉伸和成熟3个Mozzarella干酪凝胶体系形成过程中凝胶网络的形成方式。通过讨论乳脂肪含量、分布对凝胶网络形成的影响,结合分析季节、贮藏时间、热加工和均质处理等影响乳脂肪特性的关键因素,对影响Mozzarella干酪凝胶体系构建的乳脂肪特性的研究进展进行了综述。     

乳中黄嘌呤氧化还原酶的研究进展

黄嘌呤氧化还原酶属于含钼脱氢酶黄素蛋白家族，是组成乳脂肪球膜的主要蛋白，通过硫酸胺分级沉淀和DEAE-Sepharose柱可从乳脂肪球膜中纯化。XOR作为乳脂肪球膜的膜结合蛋白，在脂肪滴的包裹和分泌中起到重要的结构作用，并且在肠道能够起到一定的抗菌作用。     

Research Progress on Milk Fat Globule Membrane Proteins

Milk fat globule membrane protein is packaged outside the fat granule during mammary gland lactating. Milk fat globule membrane has three-layered structure composed of phospholipids,sphingolipids and proteins. Milk fat globule membrane protein contains more than one hundred kinds of proteins,of which there are the most abundant of eight kinds of proteins including mucin 1,xanthine oxidoreductase,mucin 15,CD36,butyrophilin,lactadherin,adipophilin,fatty acid binding protein .Milk fat globule membrane protein has been shown to have special value which reflects the physiological state of cow,affects the growth of calf and maternal immune as a source of nutrition and immunity for calves,and affects the human and animal's immunity regulation and physical fitness,it may be applied to treat diseases in the future. This article summaries the study of milk fat globule membrane protein in recent years aimed at describing the source,composition of the milk fat globule membrane proteins,introducing a novel established structure of milk fat globule membrane protein,explaining the physiological characteristics of some main proteins and progress in milk fat globule membrane proteins research and making recommendations for future research directions.     

过滤器辅助样品前处理法测定乳脂肪球膜蛋白质的研究

牛乳是世界上消费最广泛的乳类,并为消费者提供必需的营养物质。牛乳包括蛋白质,脂肪,糖类,维生素和矿物质。蛋白质是牛乳的重要组成部分,包括酪蛋白、乳清蛋白及乳脂肪球膜蛋白质。牛乳乳脂肪球被乳脂肪球膜覆盖,乳脂肪球膜是一个含有3层膜的膜结构,其上附着或者包含蛋白质。近些年来,对于乳中蛋白质的鉴定成为新的研究热点。随着蛋白质组学技术的发展,鉴定出的蛋白质的种类和数量都在增加。但是由于乳脂肪球膜的特殊性质,在牛乳乳脂肪球膜蛋白质的鉴定中,缺乏方便快捷及效果好的方法。作者运用过滤器辅助样品前处理法（FASP）结合纳升液相质谱（NanoLC-MS/MS）测定牛乳乳脂肪球膜蛋白质的种类和数量,共鉴别出169种蛋白质,是目前鉴别数量最大的一种方法。此方法的建立为今后乳脂肪球膜蛋白质研究领域提供一种方便快捷准确的试验工具。     

Shifts in the Holstein dairy cow milk fat globule membrane proteome that occur during the first week of lactation are affected by parity

Background: The milk fat globule membrane(MFGM) proteomes of colostrum and transition milk are rich sources of proteins that are likely important for neonatal calf health. In addition, characterization of these proteomes could also yield valuable information regarding mammary gland physiology of the early postpartum lactating cow. The objectives of this research were to characterize the MFGM proteomes of colostrum and transition milk through sample collections at four timepoints postpartum, including the first milking(M1, colostrum), second milking(M2, transition milk), fourth milking(M4, transition milk), and fourteenth milking(M14, mature milk), and compare these proteomes between multiparous(MP; n = 10) and primiparous(PP; n = 10) Holstein dairy cows. Isolated MFGM proteins were labeled using Tandem Mass tagging and analyzed using liquid chromatography-tandem mass spectrometry(LC-MS/MS). Protein identification was completed using MASCOT and Sequest in Proteome Discoverer 2.2. The scaled abundance values were analyzed using PROC MIXED in SAS to determine the effects of milking(MIL), parity(PAR), and MIL × PAR. The adaptive false-discovery rate(FDR)-adjusted P values were determined using PROC MULTTEST. Protein characterization and bioinformatic analysis were completed using a combination of PANTHER, Blast, and Uniprot.Results: A total of 104 common proteins were identified in each of the MFGM samples. Statistical analysis revealed that70.2% of identified proteins were affected by MIL. Of these, 78.1% were lower in M14 compared with M1, including immune-related proteins lactotransferrin, lactadherin and hemopexin. Parity affected 44.2% of proteins. Of the proteins affected by PAR, 84.8% were higher in MP cows compared with PP cows, including apolipoprotein E and histones 2 A, 2 B, 3,and 4 b. Butyrophilin subfamily 1 member 1 A and annexin 5 were higher in samples from PP cows. Milking × parity affected32.7% of identified proteins, including lactotransferrin, gelsolin, vitamin D binding protein, and S100 proteins.Conclusions: This research supports previous findings that the Holstein MFGM proteome changes rapidly during the first week of lactation. In addition, this research identifies the impact of parity on the colostrum and transition milk MFGM proteomes, which may be important for milk-fed calf health or for the identification of protein biomarkers for mammary functionality.     

Dimensional analysis of milk fat globules in sow milk: effects of the lactation stage and fat content and comparison with vaccine milk

To assess the differences in the granulometry of milk fat globules between swine and bovine species, milk samples from 30 lactating sows were analyzed for fat globule dimensions and compared with cow milk samples. Results showed differences between the fat globules: sow milk presents reduced globule diameters compared with cow milk (volume-weighted diameter 2.62 vs. 3.27 µm, p < 0.001) and reduced interglobular distance. A positive relationship was observed between milk fat content and globule diameter, while a slight, insignificant inverse trend was detected between the day of lactation and fat globule diameter. These complex interactions between milk lipids, globule membrane proteins, and globule dimensions provide a better understanding of digestion/absorption phenomena in the design of milk replacers.