超声波提取牛奶中细菌DNA方法的优化

本试验通过采集乌鲁木齐燕儿窝种牛场2003年5月份所有泌乳奶牛的牛奶样品，使用不同超声波功率（0、100、120、140、160 W）处理后，采用十六烷基三甲基溴化铵（CTAB）、十二烷基磺酸钠（SDS）法提取牛奶中细菌DNA，并通过DNA浓度、纯度和细菌通用引物扩增16S rDNA的V6-V8区判定DNA的质量，筛选出提取牛奶中细菌DNA的最佳方法。结果表明，未使用超声波处理样品，直接采用CTAB、SDS法提取出的DNA无法扩增出细菌16S rDNA V6-V8区，而使用不同超声波功率（100、120、140、160 W）处理后能扩增出细菌16S rDNA V6-V8区，其中超声波功率140 W处理样品10 min并结合CTAB法提取牛奶中细菌DNA的浓度最高，为203.35 μg/mL。因此，超声波功率140 W处理样品并结合CTAB法提取牛奶中细菌DNA的方法最优，能满足从分子水平上进一步研究乳房炎相关细菌的要求。

Improvement of Ultrasonic Power on DNA Extraction Method from Milk Bacterial

All dairy cows’ milk were collected from Urumqi Yanerwo cow farm in May 2013.Treated those samples with different ultrasonic power （0，100，120，140，160 W） after mixed，then extracted the milk bacterial DNA with the CTAB and SDS methods，respectively，according the DNA concentration, purity and bacterial universal primers of 16S rDNA V6-V8 region to judging the quality of DNA，finally screen out the best DNA extraction method.The results showed that the DNA which was extracted by the CTAB and SDS methods after treated with ultrasonic power 0 W for 10 min couldn’t amplify the V6-V8 of 16S rDNA.Meanwhile，the V6-V8 of 16S rDNA could been amplified with the other ultrasonic power (100，120，140，160 W)，and the result showed multifariously.The highest DNA density was 203.35 μg/mL，which was extracted by the CTAB method and treated with ultrasonic power 140 W.Results indicated that using the CTAB method after treated those samples with ultrasonic power 140 W was the best way to get the significantly higher DNA density，this method could further satisfy the requirements of studying about microbial populations of mastitis from the molecular level.