title: Lethal photosensitisation of Prevotellaceae under anaerobic conditions by their endogenous porphyrins.
abstract: BACKGROUND
  Oxygen is generally considered essential for lethal photosensitisation by photodynamic processes. The oral anaerobes, Prevotella intermedia and P. nigrescens are known to be photosensitive, but are also extremely sensitive to the cytotoxic effects of oxygen.
  
  
  METHODS
  The Prevotellaceae were exposed to two 405 nm light sources for different exposure times in an anaerobic chamber. Viable counts of the light exposed samples were compared to light-free controls to determine the proportion of bacteria killed.
  
  
  RESULTS
  Lethal photosensitivity was demonstrated against P. intermedia and P. nigrescens. The proportions of bacteria killed by either the light-emitting diode or laser pointer were similar at a given energy density (J/cm(2)).
  
  
  CONCLUSIONS
  Lethal photosensitivity was demonstrated in two species of Prevotella under anaerobic conditions.
authors.affiliation: Department of Health Services Research, University of Liverpool, Liverpool, UK; School of Dentistry, University of Liverpool, Liverpool, UK. Electronic address: chope@liv.ac.uk.
authors.forename: Christopher K
authors.initials: CK
authors.lastname: Hope
authors.affiliation: School of Dentistry, University of Liverpool, Liverpool, UK.
authors.forename: Michael
authors.initials: M
authors.lastname: Strother
authors.affiliation: School of Life Sciences, University of Liverpool, Liverpool, UK.
authors.forename: Haidee K
authors.initials: HK
authors.lastname: Creber
authors.affiliation: Department of Health Services Research, University of Liverpool, Liverpool, UK; School of Dentistry, University of Liverpool, Liverpool, UK.
authors.forename: Susan M
authors.initials: SM
authors.lastname: Higham
mesh_terms: D000693:Anaerobiosis / Q000502:physiology / Q000528:radiation effects; D017209:Apoptosis / Q000502:physiology* / Q000528:radiation effects; D004307:Dose-Response Relationship, Radiation; D008027:Light; D010100:Oxygen / Q000378:metabolism*; D011166:Porphyrins / Q000378:metabolism*; D018720:Prevotella / Q000145:classification / Q000502:physiology* / Q000528:radiation effects*; D011829:Radiation Dosage; D011836:Radiation Tolerance / Q000502:physiology*; D013045:Species Specificity
chemical_list: D011166:Porphyrins; D010100:Oxygen
keywords: Light; Photodynamic therapy; Prevotella intermedia; Prevotella nigrescens; Protoporphyrin IX