Dual-Stable-Isotope-Probed Raman microspectroscopy reveals the metabolic dynamic of Streptococcus mutans

• Published in: Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy Molecular and biomolecular spectroscopy, 2024-01, Vol.304, p.123318, Article 123318
• Main Authors: Sun, Yanfei, Li, Shanshan, Si, Yuan, Niu, Yufen, Yang, Jiazhen, Liu, Yuhan, Dong, Lei, Zhu, Pengfei, Dai, Jing, Yang, Fang
• Format: Article
• Language: English
• Subjects: 13C-glucose; Heavy water; Metabolism; Single-cell Raman spectrum; Streptococcus mutans
• ISSN: 1386-1425
• DOI: 10.1016/j.saa.2023.123318

[Display omitted] •The peak intensity of phenylalanine assums the biomarker for quantifying microbial glucose metabolism.•Raman spectroscopy based on isotope labeling quantify the cariogenicity of oral microorganisms.•Double SIP-substrate labeling facilitates simultaneous observation of microbial glucose metabolism and cell activity.•Fungi affects the cariogenicity of Streptococcus mutans. Streptococcus mutans (S. mutans) is regarded as a cariogenic pathogen with the ability to metabolize sugars and form organic acids. However, its actual timely level of glucose consumption and cellular vitality in a polymicrobial culture system remains largely unknown. To tackle this challenge, we employed the S. mutans UA159 as a model and developed a dual-stable-isotope-probed Raman microspectroscopy method (Dual SIP-Raman) to simultaneously profile the general metabolic activity and glucose assimilative activity in situ. (i) Mono-SIP substrate feeding revealed that 0.5% 13C-glucose and 30% D2O were proper doses in the medium to obtain prominent and quantitative band shifts along with the 13C or D2O incorporation. In addition, the intensity of the 13C peak of phenylalanine (Phe) is proposed as a Raman-based biomarker for glucose utilization in a cell. (ii) The state of dual SIP substrate incorporation of 13C-glucose and D2O could be visualized by the corresponding spectral “red shifts” of Raman-scattered emissions; moreover, we also demonstrated that 13C/12C analysis was closely correlated with the C-D ratio. (iii) The application of the dual 13C-glucose and D2O feeding approach on a mock microbiota of S. mutans UA159 and C. albicans ATCC14053 revealed a stimulatory effect of fungus on both the glucose intake rate and general metabolic vitality of S. mutans UA159 (p