流式细胞术在乳酸菌自溶检测中的应用

Flow Cytometric Method Assessment of Autolysis of lactic acid bacteria

摘要:

摘要：【目的】使用流式细胞术（FCM）建立一种新的检测方法，可快速筛选自溶度不同的乳酸菌菌株。【方法】菌悬液经20 mmol/L 的PI-PBS染液在4℃条件下避光染色30 min，上流式细胞仪进行测定，检测器激发光波长488 nm，检测波长630 nm，每个样品收集1×105个细胞，联机使用CellQuest软件分析结果。【结果】阳性染色细胞数与细胞总数之比很好地反映菌液中自溶细胞与非自溶细胞的比例关系，整个检测过程耗时仅为1 h左右。【结论】与传统检测方法比较，FCM测定结果稳定可靠，检测时间短，为乳酸菌的自溶特性研究及筛选自溶度不同的菌株用作商业发酵剂提供了便利条件。

Abstract:

Abstract：[Objective] The autolysis rate of lactic acid bacteria is crucial for their applications as dairy starters and as probiotics. To establish a rapid and sensitive method to detect autolysis rate of lactic acid bacteria, A Flow Cytometric Method (FCM) can be employed. [Methods] Cell suspensions were dyed 30 min by PI-PBS (20 mmol/L) in 4℃ dark environment. A 630 nm long pass filter was used to collect the red fluorescence (FL3 488 nm), and 1×105 cells were collected each sample. Data were analyzed by CellQuest online analysis system. Test time depended on different concentrations of cell suspensions, were about 40 s to 100 s. FCM enumerations were accurate down to a concentration of 104 cells/mL. [Results] Correlation test results reported that there were no significant difference between FCM test and other normal methods for the determination of Autolysis rate of lactic acid bacteria. [Conclusion] FCM by use of fluorescent probes propidium iodide (PI) is a good analytical method that allows the rapid and sensitive measurement of viability of lactic acid bacteria. This FCM method provides tools to assess the viability of different lactic acid bacteria in fermentation starters and probiotic products.