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BioAssay: AID 519381

Induction of photoactive porphyrins in Escherichia coli K-12 exposed to irradiation at 120 J.cm2 light by HPLC

Due mainly to the extensive use of antibiotics, the spread of multiresistant bacterial strains is one of the most worrying threats to public health. One strategy that can be used to overcome potential shortcomings might be the inactivation of these microorganisms by 5-aminolevulinic acid (5-ALA) or 5-ALA derivative-mediated photodynamic therapy (PDT). 5-ALA has no photoactive properties, but when more ..
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 Tested Compounds
 Tested Compounds
All(1)
 
 
Active(1)
 
 
 Tested Substances
 Tested Substances
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Active(1)
 
 
 Related BioAssays
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AID: 519381
Data Source: ChEMBL (667249)
Depositor Category: Literature, Extracted
BioAssay Version:
Deposit Date: 2011-09-18
Modify Date: 2014-05-24

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BioActive Compound: 1
Description:
Title: Effects on gram-negative and gram-positive bacteria mediated by 5-aminolevulinic Acid and 5-aminolevulinic acid derivatives.

Abstract: Due mainly to the extensive use of antibiotics, the spread of multiresistant bacterial strains is one of the most worrying threats to public health. One strategy that can be used to overcome potential shortcomings might be the inactivation of these microorganisms by 5-aminolevulinic acid (5-ALA) or 5-ALA derivative-mediated photodynamic therapy (PDT). 5-ALA has no photoactive properties, but when it is given exogenously, it acts as a precursor of photosensitive porphyrins predominantly in tissues or organisms that are characterized by a high metabolic turnover, such as tumors, macrophages, and bacteria. However, the weak ability of 5-ALA to cross biological barriers has led to the introduction of more lipophilic derivatives, such as methyl aminolevulinate or hexyl aminolevulinate, which display improved capacities to reach the cytoplasm. Starting from the hypothesis that more lipophilic compounds carrying only a permanent positive charge under physiological conditions may more easily cross the bacterial multilayer barrier, we have tested the efficacies of some 5-ALA n-alkyl esters for the inactivation of bacteria. For this purpose, different bacterial strains were incubated with 5-ALA or its corresponding esters of different lipophilicities. Then, the bacteria were irradiated with light and the numbers of CFU post-PDT were counted and compared to those for the controls, which were kept in the dark. Furthermore, the total amount of accumulated porphyrins was quantified by high-pressure liquid chromatography analysis. In our studies, analysis of the bacterial extracts revealed the presence of all the porphyrins involved in heme biosynthesis, from uroporphyrin to protoporphyin IX. The efficacy of bacterial inactivation was a function of the total amount of porphyrins produced, independently of their nature. The 5-ALA methyl and butyl esters were the most effective compounds with respect to the photodynamic inactivation of bacteria. We observed significant differences in terms of the optimal drug concentration, bactericidal activities, and porphyrin production.
(PMID: 18195063)
Comment
Putative Target:

ChEMBL Target ID: 50049
Target Type: ORGANISM
Pref Name: Escherichia coli K12
Organism: Escherichia coli K-12
Tax ID: 83333
Confidence: Target assigned is non-molecular
Relationship Type: Non-molecular target assigned
Categorized Comment
Assay Type: Functional

Assay Data Source: Scientific Literature

BAO: Assay Format: organism-based format

Result Definitions
TIDNameDescriptionHistogramTypeUnit
OutcomeThe BioAssay activity outcomeOutcome
1Activity activity commentActivity activity commentString
2Activity standard flagActivity standard flagInteger
3Activity qualifierActivity qualifierString
4Activity published valueActivity published valueFloat
5Activity standard valueActivity standard valueFloat

Data Table (Concise)
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