热激处理罗伊氏乳杆菌(Lactobacillus reuteri)增强其抗逆性的研究

Improvement of stress tolerance of Lactobacillus reuteri by heat shock

为了研究热激对益生菌抗逆性的影响,本研究以罗伊氏乳杆菌(Lactobacillus reuteri)为实验对象,以存活率、抗性基因表达为指标,采用平板计数法研究了热激处理对罗伊氏乳杆菌在后续高温和高盐逆境下存活率提高的效果,并用q PCR方法检测基因表达水平。结果表明:热激预处理(40℃,30 min)罗伊氏乳杆菌之后,能显著(p<0.05)提高其在后续高温(45、48、51℃),高盐(0.1%、0.3%、0.7%Na Cl,m/v)以及氧化逆境(H2O2,0.3、0.6、1.2 mmol/L)下的存活率。此外,热激预处理(40℃,30 min)还能显著(p<0.05)提高巯基过氧化物酶(thiol peroxidase)和抗氧化蛋白(peroxiredoxin)的转录表达水平。说明热激处理通过提高罗伊氏乳杆菌抗逆基因的表达,增强其对于后续逆境的抗性。该研究结果为益生菌的规模化应用提供了理论依据。

In order to assay the effect of heat shock（HS） on the stress tolerance of the probiotic bacterium,Lactobacillus reuteri serves as the research objective in this study. The survival and gene expression of L. reuteri under stress condition has been determined via CFU counting method and qPCR analysis. The results showed that the HS pretreatment （ 40 ℃, 30 min ） significantly （p 〈 0.05 ） increased the survival of L.reuteri under the subsequent heat stress （ 45,48,51% ）, salt stress （ 0.1%, 0.3% ,0.7%, m/v） and oxidative stress（ 0.3,0.6,1.2 mmol/L）, respectively. In addition, the HS pretreatment （ 40 ℃, 30 min） markedly enhanced the transcriptional expression of thiol peroxidase and peroxiredoxin.It suggested that HS pretreatment could improve stress tolerance via increasing the expression of anti-stress genes.These results provide a theoretical basis for the large -scale application of probiotics.