A Preliminary Study On Discrimination Of Oral Microorganisms By ～1HNMR-based Metabonomics

Metabonomics emerged in the 2000s as a new method for qualitative and quantitative measurement of whole low-molecular metabolites in a living system or a cell. NMR-based metabonomics is the main method in this research. NMR-based metabonomics measures low-molecular metabolites in cells of organ and tissue to obtain living system' s NMR spectra. Combining with the pattern recognition method, NMR data can be further analyzed and the biological significance of the metabolites can be discovered..Objective To evaluate the feasibility of identification of Streptococcus mutans and Actinomyces viscosus by ~1HNMR-based metabonomics, the extracellular metabolites of the two kind of bacteria in cultural solution were detected to get the characteristic ~1H-NMR spectra and the pattern recognition software (PCA) were employed to complete further analysis.Methods1. Growth observation of the strainsStreptococcus mutans and Actinomyces viscosus were respectively inoculated in modified TPY culture, which underwent the morphological observation and the biochemical identification. The growth curves of the inoculated bacteria were drawn by turbidimetry to observe the growth status of the two kind of bacteria in modified TPY culture.2. NMR spectrum of samplesThe ~1H-NMR of the extracellular metabolite samples were analyzed by the internal standard method to get free induction decay information. Acquired ~1H-NMR spectra was treated by MESTREC software to undergo the Fouier transition.3. PCA analysis200 integration values from every sample spectrum were obtained through MESTREC software. The obtained data were transformed into Excel tables and analyzed by the principal component analysis (PCA) method.Results In modified TPY culture, Streptococcus mutans and Actinomyces viscosus grew well and showed typical morphological and the biochemical characteristics and stable growth line. Typical NMR pecks of extracellular metabolites of the two kind of bacteria could be clearly identified in NMR spectra. The scores of PC of same bacteria demonstrated a clustering phenomenon. From the resultant loading plots, there were obvious chemical shifts which were responsible for the separation of the two groups of samples. The most important chemical shifts, such as 7.08ppm, 2.56ppm and 0.8002ppm, represent the difference of the two kind of bacteria.Conclusion By ~1HNMR-based metabonomics, we can discriminate the extracellular metabolites of Streptococcus mutans and Actinomyces viscosus well. This study clearly shows the great potential of the NMR-based metabonomics approach to rapidly identify oral microorganism.