The interaction of lipopolysaccharides with phenothiazine dyes

Усачева, М. Н.; Teichert, Matthew C.; Biel, Merrill A.

doi:10.1002/lsm.10226

Cited by 91 publications

(85 citation statements)

References 24 publications

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“…The present study continues our previous investigations of the interaction between the phenothiazine dyes, methylene blue (MB) and toluidine blue (TB), and gram-negative bacteria to clarify the differences in the photobactericidal efficacies of these dyes [1][2][3]. MB and TB are commercial phenothiazine dyes widely accepted in medical practice.…”

Section: Introductionsupporting

confidence: 61%

“…Previously we demonstrated that MB and TB readily form metachromatic complexes with LPS extracted from gram-negative bacteria [2]. It should be emphasized that not only does TB interact much better with LPS than MB, but TB also causes more bacterial photodamage [1,2].…”

Section: Introductionmentioning

confidence: 93%

“…Dye stock solutions of 600 mM were prepared in 0.45% saline. The dye concentration in experimental suspensions was determined spectrophotometrically using calibration curves [2]. Bacteria P. aeruginosa ATCC 27853 was aerobically grown on tryptic soy agar (Remel Microbiology, Lenexa, KS) at 378C for 24 hours.…”

Section: Dyesmentioning

confidence: 99%

“…It should be emphasized that not only does TB interact much better with LPS than MB, but TB also causes more bacterial photodamage [1,2]. Therefore, the initial interaction between TB and LPS could be responsible for the greater total bacterial photodamage with TB as compared to MB.…”

Section: Introductionmentioning

confidence: 99%

“…The fact that PaA is responsible for the fluorescence of P. aeruginosa cells induced by visible light makes it possible to associate the observed changes in the P. aeruginosa fluorescence with the interactions between the PaA system and the dyes. Moreover, the selection of P. aeruginosa for the present investigation was also motivated by the very significant effect of CaCl 2 to inhibit the interaction of TB and MB with pseudomonal LPS and bacterial photodamage induced by these dyes [2,3].…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Interaction of the photobactericides methylene blue and toluidine blue with a fluorophore in Pseudomonas aeruginosa cells

Усачева¹,

Teichert²,

Usachev

et al. 2008

Lasers Surg Med

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Background and Objectives: The difference in photobactericidal efficacy between methylene blue (MB) and toluidine blue (TB) may be explained by their involvement with proteins, lipopolysaccharides (LPS), and siderophores and siderophore-receptor protein complexes on the bacterial outer membrane. This study aims to determine if this is the case by using the fluorescence given off by a pseudomonal siderophore named pyoverdin. Study Design/Materials and Methods: Confocal laser scanning microscopy was used to observe the fluorescence of Pseudomonas aeruginosa cells excited at 488 nm in the presence of increasing dye concentrations. Results: Cellular fluorescence at 522 nm progressively decreased with increasing dye concentrations. The SternVolmer constants for cellular fluorescence quenching with the dyes were compared to the association constants for dyes complexed with LPS. The quenching of cellular fluorescence was associated with the formation of a ground-state complex between the dyes and pyoverdin-FpvA protein system. MB readily complexed with this system, whereas TB complexed more strongly with LPS. Conclusion: The different affinities of the dyes for both pyoverdin-protein and LPS will affect the contributions of the dyes' interactions with these biopolymers to the overall bacterial photodamage.

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Section: Introductionsupporting

confidence: 61%

Section: Introductionmentioning

confidence: 93%

Section: Dyesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Interaction of the photobactericides methylene blue and toluidine blue with a fluorophore in Pseudomonas aeruginosa cells

Усачева¹,

Teichert²,

Usachev

et al. 2008

Lasers Surg Med

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Gaining Access to Bacteria through (Reversible) Control of Lipophilicity

Galstyan

Putze

Dobrindt

2017

Chemistry A European J

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The development of antimicrobial photodynamic therapy (aPDT) is highly dependent on the development of suitable photosensitizers (PSs); ideally, affinity of a PS towards bacterial cells should be much higher than that towards mammalian cells. A cationic charge on a PS may lead to its selective binding to bacteria mediated through electrostatic interaction; however, the photodynamic outcome is highly dependent on the lipophilicity of the PS. Herein, we report the aPDT effect of silicon(IV) phthalocyanine derivatives bearing four positive charges and methyl, phenyl, or naphthyl substituents at the periphery of the macrocycle. We show that through modulation of lipophilicity, it is possible to find a therapeutic window in which bacteria, but not mammalian cells, are effectively killed. The photobiological activity of these PSs was significantly lower when they were deployed as host-guest complexes with cucurbit[7]uril (CB[7]). CB[7] blocks the hydrophobic part of the PS and reduces its lipophilicity, indicating that a hydrophobic interaction with the outer membrane of bacterial cells is essential for aPDT activity. The efficacies of the obtained PSs have been evaluated by using different uropathogenic E. coli isolates and human kidney epithelial carcinoma cells.

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Efficacy of photodynamic therapy as an adjunct to scaling and root planing on clinical parameters and microbial composition in subgingival plaque of periodontitis patients: A split‐mouth randomized clinical trial

Nie,

Huang,

Peng

et al. 2024

Journal of Periodontology

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BackgroundThe aim of this study was to assess the efficacy of photodynamic therapy (PDT) as an adjunct to scaling and root planing (SRP) on clinical parameters and microbial composition in subgingival plaque of periodontitis patients.MethodsSeventeen patients were included in this split‐mouth randomized clinical trial. Sites with probing pocket depth (PPD) ≥5 mm in combination with bleeding on probing in different quadrants were randomized into the control group, the group with a single PDT application right after SRP, and the group with three repeated PDT applications 1 week after SRP. The subgingival plaque was collected for 16S rRNA gene sequencing at baseline, Week 2, and Week 8.ResultsSeventeen patients with 60 sites completed this 8‐week follow‐up, and 157 subgingival plaques were successfully analyzed by sequencing. Significant improvements were observed in two primary outcomes: PPD at Week 8 and subgingival microbial composition. Compared to the control group, the repeated‐PDT group showed a notable improvement in PPD, substantial alterations in the microbial profile, including a reduction in α‐diversity and anaerobic bacteria, and an increase in aerobic bacteria at Week 2. Secondary outcomes, such as clinical attachment level and sulcus bleeding index, also showed improvement at Week 8. Furthermore, both the single‐ and repeated‐PDT groups exhibited a decrease in periodontopathogens and an increase in beneficial bacteria compared with baseline.ConclusionPDT promotes changes in the microbial composition of periodontitis patients’ subgingival plaque in a direction favorable to periodontal health, and repeated PDT is a promising adjunctive therapy for periodontal treatment.

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The interaction of lipopolysaccharides with phenothiazine dyes

Abstract: Toluidine blue interacts with LPS more significantly than methylene blue in vitro. This may be one of the main factors determining its greater photobactericidal efficacy against gram-negative bacteria.

Cited by 91 publications

References 24 publications

Interaction of the photobactericides methylene blue and toluidine blue with a fluorophore in Pseudomonas aeruginosa cells

Interaction of the photobactericides methylene blue and toluidine blue with a fluorophore in Pseudomonas aeruginosa cells

Gaining Access to Bacteria through (Reversible) Control of Lipophilicity

Efficacy of photodynamic therapy as an adjunct to scaling and root planing on clinical parameters and microbial composition in subgingival plaque of periodontitis patients: A split‐mouth randomized clinical trial

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