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Photodynamic antimicrobial chemotherapy in aquaculture: photoinactivation studies of Vibrio fischeri.

Alves E, Faustino MA, Tomé JP, Neves MG, Tomé AC, Cavaleiro JA, Cunha Â, Gomes NC, Almeida A - PLoS ONE (2011)

Bottom Line: The variations in pH (6.5-8.5), temperature (10-25°C), salinity (20-40 g L(-1)) and oxygen concentration did not significantly affect the PI of V. fischeri, once in all tested conditions the bioluminescent signal decreased to the detection limit of the method (≈7 log reduction).The assays using aquaculture water showed that the efficiency of the process is affected by the suspended matter.Total PI of V. fischeri in aquaculture water was achieved under solar light in the presence of 20 µM of Tri-Py(+)-Me-PF.

View Article: PubMed Central - PubMed

Affiliation: Department of Biology, Centre for Environmental and Marine Studies, University of Aveiro, Aveiro, Portugal.

ABSTRACT

Background: Photodynamic antimicrobial chemotherapy (PACT) combines light, a light-absorbing molecule that initiates a photochemical or photophysical reaction, and oxygen. The combined action of these three components originates reactive oxygen species that lead to microorganisms' destruction. The aim was to evaluate the efficiency of PACT on Vibrio fischeri: 1) with buffer solution, varying temperature, pH, salinity and oxygen concentration values; 2) with aquaculture water, to reproduce photoinactivation (PI) conditions in situ.

Methodology/principal findings: To monitor the PI kinetics, the bioluminescence of V. fischeri was measured during the experiments. A tricationic meso-substituted porphyrin (Tri-Py(+)-Me-PF) was used as photosensitizer (5 µM in the studies with buffer solution and 10-50 µM in the studies with aquaculture water); artificial white light (4 mW cm(-2)) and solar irradiation (40 mW cm(-2)) were used as light sources; and the bacterial concentration used for all experiments was ≈10(7) CFU mL(-1) (corresponding to a bioluminescence level of 10(5) relative light units--RLU). The variations in pH (6.5-8.5), temperature (10-25°C), salinity (20-40 g L(-1)) and oxygen concentration did not significantly affect the PI of V. fischeri, once in all tested conditions the bioluminescent signal decreased to the detection limit of the method (≈7 log reduction). The assays using aquaculture water showed that the efficiency of the process is affected by the suspended matter. Total PI of V. fischeri in aquaculture water was achieved under solar light in the presence of 20 µM of Tri-Py(+)-Me-PF.

Conclusions/significance: If PACT is to be used in environmental applications, the matrix containing target microbial communities should be previously characterized in order to establish an efficient protocol having into account the photosensitizer concentration, the light source and the total light dose delivered. The possibility of using solar light in PACT to treat aquaculture water makes this technology cost-effective and attractive.

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Related in: MedlinePlus

Structure of the 5,10,15-tris(1-methylpyridinium-4-yl)-20-(pentafluorophenyl)porphyrin tri-iodide.
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Related In: Results  -  Collection


getmorefigures.php?uid=PMC3117864&req=5

pone-0020970-g001: Structure of the 5,10,15-tris(1-methylpyridinium-4-yl)-20-(pentafluorophenyl)porphyrin tri-iodide.

Mentions: 5,10,15-tris(1-methylpyridinium-4-yl)-20-(pentafluorophenyl)porphyrin tri-iodide, Tri-Py+-Me-PF (Figure 1) was prepared according to the literature [35], [36]. A stock solution of Tri-Py+-Me-PF in DMSO at 500 µM was prepared, divided into aliquots of 1.5 mL and maintained at 4°C. Before each PI assay, the porphyrin aliquot to be used was stirred at 120 rpm, until room temperature (25°C) was reached.


Photodynamic antimicrobial chemotherapy in aquaculture: photoinactivation studies of Vibrio fischeri.

Alves E, Faustino MA, Tomé JP, Neves MG, Tomé AC, Cavaleiro JA, Cunha Â, Gomes NC, Almeida A - PLoS ONE (2011)

Structure of the 5,10,15-tris(1-methylpyridinium-4-yl)-20-(pentafluorophenyl)porphyrin tri-iodide.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3117864&req=5

pone-0020970-g001: Structure of the 5,10,15-tris(1-methylpyridinium-4-yl)-20-(pentafluorophenyl)porphyrin tri-iodide.
Mentions: 5,10,15-tris(1-methylpyridinium-4-yl)-20-(pentafluorophenyl)porphyrin tri-iodide, Tri-Py+-Me-PF (Figure 1) was prepared according to the literature [35], [36]. A stock solution of Tri-Py+-Me-PF in DMSO at 500 µM was prepared, divided into aliquots of 1.5 mL and maintained at 4°C. Before each PI assay, the porphyrin aliquot to be used was stirred at 120 rpm, until room temperature (25°C) was reached.

Bottom Line: The variations in pH (6.5-8.5), temperature (10-25°C), salinity (20-40 g L(-1)) and oxygen concentration did not significantly affect the PI of V. fischeri, once in all tested conditions the bioluminescent signal decreased to the detection limit of the method (≈7 log reduction).The assays using aquaculture water showed that the efficiency of the process is affected by the suspended matter.Total PI of V. fischeri in aquaculture water was achieved under solar light in the presence of 20 µM of Tri-Py(+)-Me-PF.

View Article: PubMed Central - PubMed

Affiliation: Department of Biology, Centre for Environmental and Marine Studies, University of Aveiro, Aveiro, Portugal.

ABSTRACT

Background: Photodynamic antimicrobial chemotherapy (PACT) combines light, a light-absorbing molecule that initiates a photochemical or photophysical reaction, and oxygen. The combined action of these three components originates reactive oxygen species that lead to microorganisms' destruction. The aim was to evaluate the efficiency of PACT on Vibrio fischeri: 1) with buffer solution, varying temperature, pH, salinity and oxygen concentration values; 2) with aquaculture water, to reproduce photoinactivation (PI) conditions in situ.

Methodology/principal findings: To monitor the PI kinetics, the bioluminescence of V. fischeri was measured during the experiments. A tricationic meso-substituted porphyrin (Tri-Py(+)-Me-PF) was used as photosensitizer (5 µM in the studies with buffer solution and 10-50 µM in the studies with aquaculture water); artificial white light (4 mW cm(-2)) and solar irradiation (40 mW cm(-2)) were used as light sources; and the bacterial concentration used for all experiments was ≈10(7) CFU mL(-1) (corresponding to a bioluminescence level of 10(5) relative light units--RLU). The variations in pH (6.5-8.5), temperature (10-25°C), salinity (20-40 g L(-1)) and oxygen concentration did not significantly affect the PI of V. fischeri, once in all tested conditions the bioluminescent signal decreased to the detection limit of the method (≈7 log reduction). The assays using aquaculture water showed that the efficiency of the process is affected by the suspended matter. Total PI of V. fischeri in aquaculture water was achieved under solar light in the presence of 20 µM of Tri-Py(+)-Me-PF.

Conclusions/significance: If PACT is to be used in environmental applications, the matrix containing target microbial communities should be previously characterized in order to establish an efficient protocol having into account the photosensitizer concentration, the light source and the total light dose delivered. The possibility of using solar light in PACT to treat aquaculture water makes this technology cost-effective and attractive.

Show MeSH
Related in: MedlinePlus