基于信号分子AI-2活性的发酵黏液乳杆菌2-1分泌胞外多糖的研究  

Exopolysaccharides secretion of Limosilactobacillus fermentum 2-1 based on AI-2 activity

作　　者：张菁 顾悦[1] 田建军[1] 贺银凤[1] ZHANG Jing;GU Yue;TIAN Jianjun;HE Yinfeng(College of Food Science and Engineering,Inner Mongolia Agricultural University,Hohhot 010018,Inner Mongolia,China)

机构地区：[1]内蒙古农业大学食品科学与工程学院,内蒙古呼和浩特010018

出　　处：《微生物学通报》2025年第3期1234-1249,共16页Microbiology China

基　　金：国家自然科学基金(32201996);内蒙古自治区直属高校科研项目(BR220503)。

摘　　要：【背景】LuxS/自体诱导物-2(autoinducer-2,AI-2)群体感应系统可以通过分泌信号分子调控菌体细胞环境适应的过程,胞外多糖在保护细胞免受外界环境的刺激、伤害等方面也有着至关重要的作用,但二者之间的相互关系并不明确。【目的】探究不同培养条件下发酵黏液乳杆菌(Limosilactobacillus fermentum)2-1的AI-2活性与胞外多糖产量的关系。【方法】采用苯酚-硫酸法及哈维氏弧菌(Vibrio harveyi)BB170生物发光法测定不同培养条件下发酵黏液乳杆菌2-1胞外多糖产量和信号分子AI-2活性。【结果】发酵黏液乳杆菌2-1在培养初期的细胞生长速率最快,随后菌体密度逐渐趋于稳定;信号分子AI-2活性在7 h时出现峰值,随后下降;胞外多糖产量先增加后减小,16 h时显著高于其他培养时间,达(204.30±15.98)mg/L。温度升高(44℃)或降低(23℃,30℃),菌株的菌体密度、信号分子AI-2活性和胞外多糖的产生都会受到抑制;酸性条件有利于发酵黏液乳杆菌2-1信号分子AI-2的分泌,但菌株的生长和胞外多糖产量受到抑制;菌株信号分子AI-2活性及胞外多糖产量与接种量在1%-3%范围内呈正相关;培养基碳源改变时,菌株菌体密度、信号分子AI-2活性及胞外多糖产量也随之改变。添加终浓度为100μmol/L的外源信号分子AI-2时,显著促进了发酵黏液乳杆菌2-1胞外多糖的产量(P<0.05)。【结论】在一定条件下时,信号分子AI-2活性和胞外多糖产量之间呈正相关关系。[Background]The LuxS/autoinducer-2(AI-2)quorum sensing system regulates bacterial adaptation to environmental changes by secreting signal molecules.Exopolysaccharides(EPS)play a crucial role in protecting cells from external environmental stress and damage.However,the relationship between the LuxS/AI-2 system and EPS production remains unclear.[Objective]To investigate the relationship between AI-2 activity and EPS production in Limosilactobacillus fermentum 2-1 cultured under different conditions.[Methods]The phenol-sulfuric acid method and Vibrio harveyi BB170 bioluminescence assay were employed to determine the EPS yield and AI-2 activity,respectively,of L.fermentum 2-1 cultured under different conditions.[Results]The cell growth of L.fermentum 2-1 was the fastest during the early stages of culture,after which the cell density gradually stabilized.The AI-2 activity peaked at the time point of 7 h and then decreased.The EPS production presented a trend of first rising and then declining,reaching the peak of(204.30±15.98)mg/L at the time point of 16 h,which was significantly higher than that at other time points.Both elevated(44℃)and declined(23℃,30℃)temperatures inhibited the cell density,AI-2 activity,and EPS production.Acidic conditions favored AI-2 secretion but inhibited cell growth and EPS production.AI-2 activity and EPS production were positively correlated with inoculum size within the range of 1%-3%.Changes of the carbon source altered the cell density,AI-2 activity,and EPS production.Addition of exogenous AI-2 at a final concentration of 100μmol/L promoted EPS production in L.fermentum 2-1(P<0.05).[Conclusion]Under certain conditions,there is a positive correlation between AI-2 activity and EPS production in L.fermentum 2-1.

关 键 词：群体感应 信号分子AI-2 发酵黏液乳杆菌2-1 胞外多糖 

分 类 号：TS201.3[轻工技术与工程—食品科学]