Photodynamic inactivation of recombinant bioluminescent Escherichia coli by cationic porphyrins under artificial and solar irradiation.
A faster and simpler method to monitor the photoinactivation process of Escherichia coli involving the use of recombinant bioluminescent bacteria is described here. Escherichia coli cells were transformed with luxCDABE genes from the marine bioluminescent bacterium Vibrio fischeri and the recombinant bioluminescent indicator strain was used to assess, in real time, the effect of three cationic meso-substituted porphyrin derivatives on their metabolic activity, under artificial (40 W m(-2)) and solar irradiation (approximately 620 W m(-2)). The photoinactivation of bioluminescent E. coli is effective (>4 log bioluminescence decrease) with the three porphyrins used, the tricationic porphyrin Tri-Py+-Me-PF being the most efficient compound. The photoinactivation process is efficient both with solar and artificial light, for the three porphyrins tested. The results show that bioluminescence analysis is an efficient and sensitive approach being, in addition, more affordable, faster, cheaper and much less laborious than conventional methods. This approach can be used as a screening method for bacterial photoinactivation studies in vitro and also for the monitoring of the efficiency of novel photosensitizer molecules. As far as we know, this is the first study involving the use of bioluminescent bacteria to monitor the antibacterial activity of porphyrins under environmental conditions.
Alves
Eliana
E
Department of Biology, CESAM, University of Aveiro, 3810-193, Aveiro, Portugal.
Carvalho
Carla M B
CM
Tomé
João P C
JP
Faustino
Maria A F
MA
Neves
Maria G P M S
MG
Tomé
Augusto C
AC
Cavaleiro
José A S
JA
Cunha
Angela
A
Mendo
Sónia
S
Almeida
Adelaide
A
D048908:Aliivibrio fischeri / Q000235:genetics; D000900:Anti-Bacterial Agents / Q000737:chemistry / Q000494:pharmacology; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D004926:Escherichia coli / Q000187:drug effects* / Q000235:genetics / Q000378:metabolism / Q000528:radiation effects*; D008164:Luminescent Proteins / Q000235:genetics / Q000378:metabolism*; D050296:Microbial Viability / Q000187:drug effects / Q000528:radiation effects; D017319:Photosensitizing Agents / Q000737:chemistry / Q000494:pharmacology*; D011166:Porphyrins / Q000737:chemistry / Q000494:pharmacology*; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism
D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D008164:Luminescent Proteins; D017319:Photosensitizing Agents; D011166:Porphyrins; D011994:Recombinant Proteins