title: Determination of porphyrins in oral bacteria by liquid chromatography electrospray ionization tandem mass spectrometry.
abstract: Biofilms in the oral cavity can be visualized by fluorescence and a common assumption is that the endogenously produced porphyrins in certain bacteria give rise to this fluorescence. Porphyrin content in oral bacteria has been sparingly investigated, and non-selective detection techniques such as utilizing the Soret fluorescence band of porphyrins are often used. In the present study, a quantitative and selective method for the determination of porphyrins in oral bacteria has been developed and validated using high performance liquid chromatography-tandem mass spectrometry. Lysis of bacteria using Tris-EDTA buffer together with ultrasonication showed high microbial killing efficiency ≥99.98%, and sample clean-up using C18-solid phase extraction resulted in low matrix effects ≤14% for all analytes. Using this method, the porphyrin content was determined in the two oral pathogens Aggregatibacter actinomycetemcomitans and Porphyromonas gingivalis, as well as for baker's yeast, Saccharomyces cerevisiae. Uroporphyrin, 7-carboxylporphyrin, 6-carboxylporphyrin, coproporphyrin, and protoporphyrin IX were identified in the investigated microorganisms, and it was shown that the porphyrin profile differs between the two bacteria, as well as for S. cerevisiae. To our knowledge, this is the first time the porphyrin profile has been determined for the bacterium A. actinomycetemcomitans.
authors.affiliation: Department of Environmental Science and Analytical Chemistry, Analytical and Toxicological Chemistry, 106 91, Stockholm, Sweden.
authors.forename: Jonas
authors.initials: J
authors.lastname: Fyrestam
authors.forename: Nadja
authors.initials: N
authors.lastname: Bjurshammar
authors.forename: Elin
authors.initials: E
authors.lastname: Paulsson
authors.forename: Annsofi
authors.initials: A
authors.lastname: Johannsen
authors.forename: Conny
authors.initials: C
authors.lastname: Östman
mesh_terms: D016976:Aggregatibacter actinomycetemcomitans / Q000378:metabolism*; D000818:Animals; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D006801:Humans; D009055:Mouth / Q000382:microbiology*; D011166:Porphyrins / Q000378:metabolism*; D016966:Porphyromonas gingivalis / Q000378:metabolism*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods; D053719:Tandem Mass Spectrometry / Q000379:methods*
chemical_list: D011166:Porphyrins