Photodynamic action of methylene blue: Repair and mutation in Escherichia coli

Menezes, Sara L. S.; Capella, Marcia A. M.; Caldas, L.R.

doi:10.1016/1011-1344(90)85062-2

Cited by 82 publications

(44 citation statements)

References 20 publications

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“…1). MB has been used almost as often as TBO for antimicrobial PDT (30,46,48,61). DMMB was found by O'Neill et al to be the most effective PS compared to other phenothiazinium dyes tested against the gram-positive bacterium Streptococcus sanguis (34).…”

Section: Resultsmentioning

confidence: 99%

Photodynamic Inactivation of Bacillus Spores, Mediated by Phenothiazinium Dyes

Demidova

Hamblin

2005

Appl Environ Microbiol

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Spore formation is a sophisticated mechanism by which some bacteria survive conditions of stress and starvation by producing a multilayered protective capsule enclosing their condensed DNA. Spores are highly resistant to damage by heat, radiation, and commonly employed antibacterial agents. Previously, spores have also been shown to be resistant to photodynamic inactivation using dyes and light that easily destroy the corresponding vegetative bacteria. We have discovered that Bacillus spores are susceptible to photoinactivation by phenothiazinium dyes and low doses of red light. Dimethylmethylene blue, methylene blue, new methylene blue, and toluidine blue O are all effective, while alternative photosensitizers such as Rose Bengal, polylysine chlorin(e6) conjugate, a tricationic porphyrin, and a benzoporphyrin derivative, which easily kill vegetative cells, are ineffective. Spores of Bacillus cereus and B. thuringiensis are most susceptible, B. subtilis and B. atrophaeus are also killed, and B. megaterium is resistant. Photoinactivation is most effective when excess dye is washed from the spores, showing that the dye binds to the spores and that excess dye in solution can quench light delivery. The relatively mild conditions needed for spore killing could have applications for treating wounds contaminated by anthrax spores, for which conventional sporicides would have unacceptable tissue toxicity.

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Section: Resultsmentioning

confidence: 99%

Photodynamic Inactivation of Bacillus Spores, Mediated by Phenothiazinium Dyes

Demidova

Hamblin

2005

Appl Environ Microbiol

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“…It was reported that RecA expression in S. aureus, which triggers the SOS signal for DNA repair, is upregulated during APDT. This mechanism does not seem to be ubiquitous, however, as similar results were not found in P. aeruginosa [132]. So although nucleic acids may be oxidized as a result of APDT, the redox modifications can be reverted and the cells may not undergo cell death as a direct result of nucleic acid damage.…”

Section: Nucleic Acidsmentioning

confidence: 60%

“…Various light sources can be used to activate the PS, ranging from lasers and narrow-band LED sources to high-intensity broadband light sources [132]. Many factors such as the optical penetration depth of excitation light, wavelength, fluence, and drug-light interval have an impact on the photodynamic efficacy [206].…”

Section: Light Sourcementioning

confidence: 99%

Antibacterial photodynamic therapy: overview of a promising approach to fight antibiotic-resistant bacterial infections

et al. 2015

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Antibacterial photodynamic therapy (APDT) has drawn increasing attention from the scientific society for its potential to effectively kill multidrug-resistant pathogenic bacteria and for its low tendency to induce drug resistance that bacteria can rapidly develop against traditional antibiotic therapy. The review summarizes the mechanism of action of APDT, the photosensitizers, the barriers to PS localization, the targets, the in vitro-, in vivo-, and clinical evidence, the current developments in terms of treating Gram-positive and Gram-negative bacteria, the limitations, as well as future perspectives. Relevance for patients: A structured overview of all important aspects of APDT is provided in the context of resistant bacterial species. The information presented is relevant and accessible for scientists as well as clinicians, whose joint effort is required to ensure that this technology benefits patients in the post-antibiotic era.

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“…As an example, the application of PDT using methylene blue as a PS against E. faecalis, has been shown to functionally impair the cell wall, damage chromosomal DNA, and degrade membrane proteins (72). PDT also has been reported to break single, as well as double-stranded DNA, resulting in the disappearance of the plasmid super-coiled fraction often associated with antibiotic resistance (73,74). Singlet oxygen has a lifetime of less than 0.04 μsec, and a radius of action of less than 0.02 μm in a biological environment (75).…”

Section: Photodynamic Therapymentioning

confidence: 99%

Bioactive Chitosan Nanoparticles and Photodynamic Therapy Inhibit Collagen Degradation In Vitro

Persadmehr

Torneck

Cvitkovitch

et al. 2014

Journal of Endodontics

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This study evaluated the ability of photodynamic therapy (PDT), chitosan nanoparticles (CSnp), or their combination, to inhibit bacterial collagenase-mediated degradation of collagen. Rat type 1 fibrillar collagen matrices were untreated or treated with 2.5% glutaraldehyde (GD), 2.5% GD followed by 1% CSnp, 1% CSnp, PDT, or 1% CSnp followed by PDT. Samples, except untreated controls, were exposed to Clostridium histolyticum collagenase. The soluble digestion products were assessed by hydroxyproline assay and the remaining adherent collagen was quantified by picrosirius red (PSR) staining. Collagen treated with CSnp, PDT, or a combination of CSnp and PDT, exhibited less degradation than controls. The abundance of post-treatment residual collagen correlated with the extent of degradation. Fourier transform infrared (FTIR) spectroscopy analysis showed that PDT treatment enhanced collagen cross-linking.Immunoblotting of sedimented CSnp indicated that CSnp and collagenase bound with low affinity. However, CSnp-bound collagenase showed a significant reduction in collagenolytic activity compared with controls.III

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Photodynamic action of methylene blue: Repair and mutation in Escherichia coli

Cited by 82 publications

References 20 publications

Photodynamic Inactivation of Bacillus Spores, Mediated by Phenothiazinium Dyes

Photodynamic Inactivation of Bacillus Spores, Mediated by Phenothiazinium Dyes

Antibacterial photodynamic therapy: overview of a promising approach to fight antibiotic-resistant bacterial infections

Bioactive Chitosan Nanoparticles and Photodynamic Therapy Inhibit Collagen Degradation In Vitro

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