基于二维凝胶电泳分析健康泌乳奶牛血浆蛋白质组的个体差异

为了分析奶牛血浆蛋白质存在的个体差异，以合理选择牛血浆蛋白质组研究中试验奶牛的样本数。试验采集了临床健康的泌乳早期的初产中国荷斯坦奶牛的血液，分离血浆蛋白后用二维凝胶电泳技术分离，考马斯亮蓝G-250染色后，对分离形态好的56个蛋白点的表达丰度进行分析。结果发现，蛋白点的变异系数在8.7%～59.6%之间，且有5个蛋白点的丰度变异系数较大（35%～59.6%），用液相色谱串联离子阱质谱分析后，3个蛋白点获得有效鉴定，为转甲状腺素蛋白、载脂蛋白A1和α1酸性糖蛋白。方差分析结果表明，当样本数≥4时可有效降低组内样本间的个体差异。因此，奶牛血浆蛋白的表达存在个体差异，本试验为奶牛血浆蛋白质组研究中合理选择样本数量提供了依据。

Proteomic Analysis of Individual Variation in Plasma of Dairy Cows Using Two-dimensional Gel Electrophoresis

To investigate the interindividual variation of plasma proteome of dairy cows and evaluate the minimal size of samples for proteomic analysis. In this study, plasma samples in early lactation dairy cows were collected and the proteome profiles of these samples were analyzed using two-dimensional gel electrophoresis. After visualization proteins with Coomassie Blue G-250 solution, the coefficient of variation values of 56 protein spots were analyzed and ranged from 8.7% to 59.6%. The five proteins with coefficient of variation values ranged from 35% to 59.6% were identified by ion trap mass spectrometer, and three spots identified as transthyretin, apolipoprotein A1 and alpha 1 acid glycoprotein. Moreover, the one-way ANOVA feature showed a correlation between sample size and individual variations. The results showed that when the sample size exceeded 4, the individual variations were not significant to the whole pool. The results indicated that individual variations are encountered in plasma protein expression profiles and further for number of samples (sample size) needed to detect given protein expression differences with statistical significance.