谷胱甘肽转移酶通过代谢重编程增强变异链球菌环境适应性的功能研究

doi:10.7518/hxkq.2025.2025084

摘要/Abstract

摘要：

目的探讨谷胱甘肽转移酶（GST）对变异链球菌环境适应能力的影响。方法构建变异链球菌GST基因敲除株ΔgsT。通过转录组测序分析变异链球菌UA159野生型与其GST基因敲除株ΔgsT的基因表达差异，酸胁迫实验、过氧化氢胁迫实验分析耐酸能力、抗氧化应激能力，营养限制条件下进行生长动力学分析，荧光原位杂交实验分析在菌斑生物膜的种间竞争能力。结果与变异链球菌野生型UA159相比，敲除株ΔgsT中198个基因显著差异表达，富集于代谢、应激响应及能量稳态相关通路。耐酸实验中，敲除株ΔgsT存活率显著降低（P<0.01）。过氧化氢处理15 min后，敲除株ΔgsT存活率为38.12%（野生型为71.75%）。营养限制下，敲除株ΔgsT最大比生长速率及稳定期生物量显著降低（P<0.05）。生物膜竞争实验中，变异链球菌敲除株ΔgsT在混合生物膜中所占的比例（8.50%）较野生型（16.89%）显著下降（P<0.05）。结论 GST可通过调控代谢和应激响应相关基因，显著增强变异链球菌的耐酸、抗氧化及营养胁迫适应能力。

关键词: 谷胱甘肽转移酶, 变异链球菌, 耐酸性, 氧化应激, 种间竞争, 基因表达调控, 代谢重编程

Abstract:

Objective This study aims to investigate the impact of glutathione S-transferase (GST) on the environmental adaptability of Streptococcus mutans (S. mutans). Methods A GST knockout strain ΔgsT was constructed. Transcriptomic sequencing was performed to analyze the gene expression differences between the wild-type S. mutans UA159 and its GST knockout strain ΔgsT. Comprehensive functional assessments, including acid tolerance assays, hydrogen peroxide challenge assays, nutrient limitation growth assays, and fluorescence in situ hybridization, were conducted to evaluate the acid tolerance, antioxidant stress resistance, growth kinetics, and interspecies competitive ability of ΔgsT within plaque biofilms. Results Compared with the wild-type S. mutans, 198 genes in ΔgsT were significantly differentially expressed and enriched in pathways related to metabolism, stress response, and energy homeostasis. The survival rate of ΔgsT in acid tolerance assays was markedly reduced (P<0.01). After 15 min of hydrogen peroxide challenge, the survival rate of ΔgsT decreased to 38.12% (wild type, 71.75%). Under nutrient-limiting conditions, ΔgsT exhibited a significantly lower final OD₆₀₀ value than the wild-type strain (P<0.05). In the biofilm competition assays, the proportion of S. mutans ΔgsT in the mixed biofilm (8.50%) was significantly lower than that of the wild type (16.89%) (P<0.05). Conclusion GST enhances the acid resistance, oxidative stress tolerance, and nutrient adaptation of S. mutans by regulating metabolism-related and stress response-related genes.

Key words: glutathione S-transferase, Streptococcus mutans, acid tolerance, oxidative stress, interspecies competition, gene expression regulation, metabolic reprogramming

中图分类号:

R780.2

郑皓月, 彭显, 邹静. 谷胱甘肽转移酶通过代谢重编程增强变异链球菌环境适应性的功能研究[J]. 华西口腔医学杂志, 2025, 43(5): 728-735.

Zheng Haoyue, Peng Xian, Zou Jing. Metabolic reprogramming by glutathione S-transferase enhances environmental adaptation of Streptococcus mutans[J]. West China Journal of Stomatology, 2025, 43(5): 728-735.

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样品名称	浓度/（ng/μL）	总量/μg	OD_260/280	OD_260/230	RQN
野生型1	1 586.50	79.33	2.10	2.61	10.00
野生型2	1 691.20	59.19	2.11	2.59	9.90
野生型3	1 774.90	88.75	2.12	2.59	10.00
敲除株ΔgsT1	1 492.00	52.22	2.11	2.60	10.00
敲除株ΔgsT2	1 855.90	64.96	2.11	2.57	10.00
敲除株ΔgsT3	1 418.10	120.54	2.11	2.59	9.50

调节类型	FC>1.2	FC>1.5	FC>2
上调	99	22	8
下调	99	34	7