为评估乳杆菌表层蛋白对菌株特性的影响，该研究通过序列比对筛选出含slp基因的乳杆菌，之后用十二烷基硫酸钠-聚丙烯酰胺凝胶电泳（SDS-PAGE）对其中部分菌的slp基因表达情况进行鉴定，并测定了表层蛋白去除前后菌体生长的吸光度值、自聚集率、自成膜量、与致病菌共聚集率等特性。结果表明，4株嗜酸乳杆菌、30株卷曲乳杆菌、3株瑞士乳杆菌、30株鼠李糖乳杆菌都含有slp基因，经过SDS-PAGE鉴定了四种菌的部分菌株均表达表层蛋白，且其表层蛋白与菌株的特性密切相关。比如，在生长方面，瑞士乳杆菌去除表层蛋白前后生长能力差异很大，但氯化锂溶液和蛋白酶K两种溶液处理的吸光度值差距较小，差值仅在0.2以内；在与致病菌共聚集方面，大部分菌株在不同处理过程中没有较大差异，有趣的是，本身自聚能力弱的鼠李糖乳杆菌3-1表现出来的与致病菌极强的共聚能力，这株菌的在口腔方面的防龋潜力值得进一步探究。该研究丰富了人们对乳杆菌表层蛋白的了解，为深入探究表层蛋白的功能和应用奠定理论基础。

To evaluate the effects of surface proteins on the properties of Lactobacillus, different species containing slp gene were selected through sequence comparison. Subsequently, sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) was performed to analyze some of them. The expression of slp gene in different Lactobacillus species was evaluated, and then the light absorbance, self-aggregation rate, biofilm formation rate, and co-aggregation rate with other pathogenic microorganisms associated with each of these species were assessed before and after the removal of surface proteins. The results revealed that 4 strains of L. acidophilus, 30 strains of L. crispatus, 3 strains of L. helveticus, and 30 strains of L. rhamnosus contain slp expressed surface proteins that were identified using SDS-PAGE. These surface proteins were found to be closely related to the properties of the strains. For example, the growth of L. helveticus before and after the removal of surface proteins was found to be significantly different. However, the light absorbance of the species of interest differed only slightly (within 0.2) after lithium chloride solution and proteinase K solution treatments. Meanwhile, for co-aggregation with other pathogenic microorganisms, most of the strains demonstrated no significant differences after different treatments. Interestingly, L. rhamnosus 3-1, which exhibits weak self-aggregation, exhibited strong co-aggregation with other pathogenic microorganisms, and therefore, the anti-caries potential of this strain is worth further exploration. This research would provide more information on the surface proteins of Lactobacillus species and lays a theoretical foundation for in-depth exploration of the functions and applications of surface proteins.

国家自然科学基金项目（32072197）