抗菌肽DJK-5对变异链球菌生物膜致龋毒力因子的影响

doi:10.13591/j.cnki.kqyx.2026.10.006

摘要/Abstract

摘要：

目的探讨抗菌肽DJK-5对变异链球菌生物膜的杀菌能力和致龋相关毒力因子的影响。方法分别以0、5、10、20、40 μg/mL DJK-5作用于变异链球菌悬液,观察细菌的生长情况;分别以无菌去离子水(Con组),2%氯己定(CHX组),10、20、40 μg/mL DJK-5作用于变异链球菌生物膜,激光共聚焦显微镜观察生物膜结构的变化;蒽酮法和pH测定法检测生物膜产水不溶性胞外多糖的量和pH值;RT-qPCR检测10 μg/mL DJK-5对致龋相关毒力因子表达的影响。结果 ≥10 μg/mL DJK-5能明显抑制变异链球菌生长,DJK-5质量浓度越高,抑制作用越明显。DJK-5组生物膜中死菌比例明显大于对照组和氯己定组,DJK-5质量浓度越高,空间结构破坏越严重。DJK-5组生物膜中pH值高于对照组,20和40 μg/mL DJK-5组生物膜中pH值高于NaF组。DJK-5组生物膜产生水不溶性胞外多糖明显少于对照组,10 μg/mL DJK-5组水不溶性胞外多糖明显多于40 μg/mL DJK-5组和NaF组;DJK-5促进gtfC和gbpB基因的表达,抑制ldh、comDE和relA基因的表达。结论 DJK-5通过靶向调控变异链球菌的致龋毒力因子,显著抑制生物膜的产酸能力和胞外多糖的生成,从而表现出高效的生物膜杀菌活性。

关键词: 抗菌肽, 变异链球菌, 生物膜, 胞外多糖, 毒力因子

Abstract:

Objective To investigate the effect of DJK-5 on the bactericidal efficacy and cariogenic virulence factors of Streptococcus mutans (S. mutans) biofilms. Methods S. mutans suspensions were treated with DJK-5 at concentrations of 0, 5, 10, 20, and 40 μg/mL, and bacterial growth was observed. S. mutans biofilms were treated with sterile deionized water (Control group), 2% chlorhexidine (CHX group) and DJK-5 at concentrations of 10, 20, 40 μg/mL. The structural changes in biofilm were observed using laser confocal microscopy. The production of water-insoluble extracellular polysaccharide (IEPS) and pH values were quantified using the anthrone-sulfuric acid method and a pH meter, respectively. Additionally, the effects of 10 μg/mL DJK-5 on the expression of cariogenic virulence genes in S. mutans biofilms were detected by RT-qPCR. Results DJK-5 at concentrations ≥10 μg/mL exhibited an inhibitory effect on the growth of planktonic S. mutans. The higher the concentration of DJK-5, the more pronounced the inhibitory effect. The volume ratios of dead bacteria in the DJK-5 groups were significantly higher than those in the control and chlorhexidine group. The disruption of spatial structure became more severe with increasing DJK-5 concentrations. The pH values in DJK-5-treated biofilms were significantly higher than those in the control group, and the pH levels in the 20 and 40 μg/mL DJK-5 groups were significantly higher than those in the NaF group. The production of IEPS in DJK-5-treated biofilms was significantly lower than that in the control group. The 10 μg/mL DJK-5 group produced significantly more IEPS than the 40 μg/mL DJK-5 group and the NaF group. DJK-5 promoted the expression of gtfC and gbpB genes, while suppressed the expression of ldh, comDE, and relA genes. Conclusion DJK-5 significantly inhibits acid production and IEPS synthesis in biofilms by targeting and modulating the cariogenic virulence factors of S. mutans, thereby demonstrating highly efficient bactericidal activity against biofilms.

Key words: antimicrobial peptide, Streptococcus mutans (S. mutans), biofilms, extracellular polysaccharides, virulence factors

中图分类号:

R780.2

洪锋, 程俊翔, 段沁颜, 潘乐, 胡亚军. 抗菌肽DJK-5对变异链球菌生物膜致龋毒力因子的影响[J]. 口腔医学, 2026, 46(10): 757-762.

HONG Feng, CHENG Junxiang, DUAN Qinyan, PAN Le, HU Yajun. Effects of antimicrobial peptide DJK-5 on cariogenic virulence factors of Streptococcus mutans biofilm[J]. Stomatology, 2026, 46(10): 757-762.

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基因	引物序列(5'—3')
基因	上游	下游
16S rRNA	AGCGTTGTCCGGATTTATTG	CTACGCATTTCACCGCTACA
ldh	GGCGACGCTCTTGATCTTAG	GGTTAGCAGCAACGAGGAAG
relA	GGTTAGCAGCAACGAGGAAG	AATCACGCTTGGTATTGCTAATTG
gtfC	GGTTTAACGTCAAAATTAGCTGTATTAGC	CTCAACCAACCGCCACTGTT
gbpB	AGGGCAATGTACTTGGGGTG	TTTGGCCACCTTGAACACCT
comDE	ACAATTCCTTGAGTTCCATCCAAG	TGGTCTGCTGCCTGTTGC