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Photodynamic inactivation of biofilms formed by Candida spp., Trichosporon mucoides, and Kodamaea ohmeri by cationic nanoemulsion of zinc 2,9,16,23-tetrakis(phenylthio)-29H, 31H-phthalocyanine (ZnPc)

Junqueira, J. C.; Jorge, A. O. C.; Barbosa, J. O.; Rossoni, R. D.; Vilela, S. F. G.; Costa, A. C. B. P.; Primo, F. L.; Goncalves, J. M.; Tedesco, A. C.; Suleiman, J. M. A. H.
Fonte: SPRINGER LONDON LTD; LONDON Publicador: SPRINGER LONDON LTD; LONDON
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
68.089443%
The biofilms formed by opportunistic yeasts serve as a persistent reservoir of infection and impair the treatment of fungal diseases. The aim of this study was to evaluate photodynamic inactivation (PDI) of biofilms formed by Candida spp. and the emerging pathogens Trichosporon mucoides and Kodamaea ohmeri by a cationic nanoemulsion of zinc 2,9,16,23-tetrakis(phenylthio)-29H,31H-phthalocyanine (ZnPc). Biofilms formed by yeasts after 48 h in the bottom of 96-well microtiter plates were treated with the photosensitizer (ZnPc) and a GaAlAs laser (26.3 J cm(-2)). The biofilm cells were scraped off the well wall, homogenized, and seeded onto Sabouraud dextrose agar plates that were then incubated at 37A degrees C for 48 h. Efficient PDI of biofilms was verified by counting colony-forming units (CFU/ml), and the data were submitted to analysis of variance and the Tukey test (p < 0.05). All biofilms studied were susceptible to PDI with statistically significant differences. The strains of Candida genus were more resistant to PDI than emerging pathogens T. mucoides and K. ohmeri. A mean reduction of 0.45 log was achieved for Candida spp. biofilms, and a reduction of 0.85 and 0.84, were achieved for biofilms formed by T. mucoides and K. ohmeri...

Photodynamic inactivation of clinical isolates of Candida using Photodithazine®

Dovigo, L. N.; Carmello, J. C.; Carvalho, M. T.; Mima, E. G.; Vergani, C. E.; Bagnato, Vanderlei Salvador; Pavarina, A. C.
Fonte: Taylor and Francis; Abingdon Publicador: Taylor and Francis; Abingdon
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
57.92868%
This study evaluated the photodynamic inactivation (PDI) mediated by Photodithazine® (PDZ) against 15 clinical isolates of Candida albicans, Candida glabrata and Candida tropicalis. Each isolate, in planktonic and biofilm form, was exposed to PDI by assessing a range of PDZ concentrations and light emitting diode fluences. Cell survival of the planktonic suspensions was determined by colony forming units (CFU ml-1). The antifungal effects of PDI against biofilms were evaluated by CFU ml-1 and metabolic assay. Data were analyzed by non-parametric tests (α=0.05). Regardless of the species, PDI promoted a significant viability reduction of planktonic yeasts. The highest reduction in cell viability of the biofilms was equivalent to 0.9 log10 (CFU ml-1) for C. albicans, while 1.4 and 1.5 log10 reductions were obtained for C. tropicalis and C. glabrata, respectively. PDI reduced the metabolic activity of biofilms by 62.1, 76.0, and 76.9% for C. albicans, C. tropicalis, and C. glabrata, respectively. PDZ-mediated PDI promoted significant reduction in the viability of Candida isolates.; FAPESP (CEPID Program) (08/00601-6, 08/03994-9, 98/14270-8)

Avaliações das atividades fotossensibilizadoras do azul de metileno, da cloro-alumínio ftalocianina e do nitrosilo de rutênio no fungo Cryptococcus neoformans; Estimate of the photosensitizing activities of the methylene blue, chloroaluminum phthalocyanine and nitrosyl ruthenium complex in the fungus Cryptococcus neoformans.

Rodrigues, Gabriela Braga
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 29/08/2008 PT
Relevância na Pesquisa
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O basidiomiceto Cryptococcus neoformans é um fungo saprófita, com ampla distribuição geográfica, que é normalmente isolado de solos que contêm excretas de pombos e detritos vegetais. Apesar de saprófita, o fungo pode infectar e causar doença em uma grande variedade de hospedeiros animais, como mamíferos, aves e insetos. O número de casos de micoses graves, causadas por C. neoformans e por outros gêneros de fungos, tem aumentado em todo o mundo, principalmente devido ao aumento do número de indivíduos imunocomprometidos. Adicionalmente, a emergência de novas espécies de patógenos e a seleção de linhagens tolerantes aos antifúngicos comumente utilizados fazem com que o desenvolvimento de novas estratégias para o controle de fungos seja extremamente desejável. A inativação fotodinâmica de fungos é um método novo e promissor, que pode ser utilizado tanto para o controle de micoses (em animais e em vegetais), como para a eliminação de fungos do ambiente. A fotoinativação de fungos é baseada no uso de fotossensibilizadores que se acumulam ou que são preferencialmente metabolizados pelas células do microrganismo-alvo. A seguir, o fotossensibilizador é exposto à luz visível, que, na presença de oxigênio...

Inativação fotodinâmica de espécies de Candida e Trichophyton e de Cryptococcus neoformans com fotossensibilizadores fenotiazínicos e com uma cloroalumínio ftalocianina em nanoemulsão; Photodynamic inactivation of Candida and Trichophyton species and of Cryptococcus neoformans with phenothiazinium photosensitisers and with a chloroaluminum phthalocyanine nanoemulsion

Rodrigues, Gabriela Braga
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 12/12/2012 PT
Relevância na Pesquisa
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Espécies de fungos dos gêneros Candida e Trichophyton e Cryptococcus neoformans são os mais importantes agentes causadores de micoses em humanos. A seleção de linhagens tolerantes aos fungicidas atualmente utilizados torna extremamente necessário o desenvolvimento de novas estratégias para o controle desses patógenos. A inativação fotodinâmica (IF) de fungos baseia-se na utilização de um fotossensibilizador (FS) que se acumula preferencialmente nas células-alvo e que pode ser ativado por exposições à luz visível. A ativação do FS induz a formação de espécies reativas de oxigênio que matam a célula fúngica. O uso de FS para o tratamento de micoses é uma aplicação recente e promissora da IF de fungos. No presente estudo, foram avaliados os efeitos dos tratamentos fotodinâmicos (TF) com os FS fenotiazínicos azul de metileno (MB), azul de toluidina (TBO), novo azul de metileno (NMBN), o derivado pentacíclico do azul de metileno S137 e com uma cloroalumínio ftalocianina em nanoemulsão (ClAlPc/NE) nas leveduras Candida albicans, C. glabrata, C. krusei, C. parapsilosis, C. tropicalis, Cryptococcus neoformans e nos microconídios dos dermatófitos Trichophyton mentagrophytes e T. rubrum. Os efeitos dos TF com os diferentes FS fenotiazínicos também foram avaliados na linhagem celular L929 de camundongo. Inicialmente...

Photodynamic inactivation of biofilms formed by Candida spp., Trichosporon mucoides, and Kodamaea ohmeri by cationic nanoemulsion of zinc 2,9,16,23-tetrakis(phenylthio)-29H, 31H-phthalocyanine (ZnPc)

Junqueira, Juliana Campos; Jorge, A. O. C.; Barbosa, J. O.; Rossoni, R. D.; Vilela, S. F. G.; Costa, A. C. B. P.; Primo, F. L.; Goncalves, J. M.; Tedesco, A. C.; Suleiman, J. M. A. H.
Fonte: Springer London Ltd Publicador: Springer London Ltd
Tipo: Artigo de Revista Científica Formato: 1205-1212
ENG
Relevância na Pesquisa
68.089443%
Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP); Processo FAPESP: 09/52283-0; Processo FAPESP: 09/15363-6; The biofilms formed by opportunistic yeasts serve as a persistent reservoir of infection and impair the treatment of fungal diseases. The aim of this study was to evaluate photodynamic inactivation (PDI) of biofilms formed by Candida spp. and the emerging pathogens Trichosporon mucoides and Kodamaea ohmeri by a cationic nanoemulsion of zinc 2,9,16,23-tetrakis(phenylthio)-29H,31H-phthalocyanine (ZnPc). Biofilms formed by yeasts after 48 h in the bottom of 96-well microtiter plates were treated with the photosensitizer (ZnPc) and a GaAlAs laser (26.3 J cm(-2)). The biofilm cells were scraped off the well wall, homogenized, and seeded onto Sabouraud dextrose agar plates that were then incubated at 37A degrees C for 48 h. Efficient PDI of biofilms was verified by counting colony-forming units (CFU/ml), and the data were submitted to analysis of variance and the Tukey test (p < 0.05). All biofilms studied were susceptible to PDI with statistically significant differences. The strains of Candida genus were more resistant to PDI than emerging pathogens T. mucoides and K. ohmeri. A mean reduction of 0.45 log was achieved for Candida spp. biofilms...

Susceptibility of Candida albicans, Staphylococcus aureus, and Streptococcus mutans biofilms to photodynamic inactivation: an in vitro study

Pereira, Cristiane Aparecida; Romeiro, Rogerio Lima; Borges Pereira Costa, Anna Carolina; Silva Machado, Ana Karina; Junqueira, Juliana Campos; Cardoso Jorge, Antonio Olavo
Fonte: Springer London Ltd Publicador: Springer London Ltd
Tipo: Artigo de Revista Científica Formato: 341-348
ENG
Relevância na Pesquisa
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP); Processo FAPESP: 09/52048-1; Processo FAPESP: 10/00879-4; Processo FAPESP: 09/12005-1; The purpose of this study was to evaluate specific effects of photodynamic inactivation (PDI) using methylene blue as photosensitizer and low-power laser irradiation on the viability of single-, dual-, and three-species biofilms formed by C. albicans, S. aureus, and S. mutans. Biofilms were grown in acrylic discs immersed in sterile brain heart infusion broth (BHI) containing 5% sucrose, inoculated with microbial suspension (10(6) cells/ml) and incubated for 5 days. on the fifth day, the effects of the methylene blue (MB) photosensitizer at a concentration of 0.1 mg/ml for 5 min and InGaAlP laser (660 nm) for 98 s, alone and conjugated were evaluated. Next, the discs were placed in tubes with sterile physiological solution [0.9% sodium chloride (NaCl)] and sonicated for to disperse the biofilms. Ten-fold serial dilutions were carried and aliquots seeded in selective agar, which were then incubated for 48 h. Then the numbers CFU/ml (log(10)) were counted and analyzed statistically (ANOVA, Tukey test, p < 0.05). Scanning electron microscopy (SEM) on discs treated with PDI and control biofilms groups was performed. Significant decreases in the viability of all microorganisms were observed for biofilms exposed to PDI mediated by MB dye. Reductions (log(10)) of single-species biofilms were greater (2.32-3.29) than the association of biofilms (1.00-2.44). Scanning electron microscopy micrographs suggested that lethal photosensitization occurred predominantly in the outermost layers of the biofilms. The results showed that PDI mediated by MB dye...

Photodynamic inactivation of Streptococcus mutans and Streptococcus sanguinis biofilms in vitro

Pereira, Cristiane Aparecida; Costa, Anna Carolina Borges Pereira; Carreira, Claudia Moura; Junqueira, Juliana Campos; Jorge, Antonio Olavo Cardoso
Fonte: Universidade Estadual Paulista Publicador: Universidade Estadual Paulista
Tipo: Artigo de Revista Científica Formato: 859-864
ENG
Relevância na Pesquisa
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The purpose of this study was to evaluate specific effects of photodynamic inactivation (PDI) using erythrosine (ER) and Rose Bengal (RB) photosensitizers and a blue light-emitting diode (LED) on the viability of Streptococcus mutans and Streptococcus sanguinis biofilms. Biofilms were grown in acrylic disks immersed in broth to production of biofilms, inoculated with microbial suspension (106 cells/mL) and incubated for 48 h. After the formation of biofilms, the effects of the photosensitizers ER and RB at a concentration of 5 μM for 5 min and blue LED (455 ± 20 nm) for 180 s, photosensitizers alone and conjugated were evaluated. Next, the disks were placed in tubes with sterile physiological solution (0.9 % sodium chloride) and sonicated for to disperse the biofilms. Tenfold serial dilutions were carried and aliquots seeded in brain heart infusion agar which were then incubated for 48 h. Then the numbers colony-forming units per milliliter (CFU/mL; log 10) were counted and analyzed statistically (ANOVA, Tukey test, P ≤ 0.05). Significant decreases in the viability of all microorganisms were observed for biofilms exposed to PDI mediated by both photosensitizers. The reductions with RB and ER were, 0.62 and 0.52 log10 CFU mL -1 for S. mutans biofilms (p = 0.001)...

Photodynamic inactivation of clinical isolates of Candida using Photodithazine

Dovigo, L. N.; Carmello, J. C.; Carvalho, M. T.; Mima, E. G.; Vergani, Carlos Eduardo; Bagnato, V. S.; Pavarina, A. C.
Fonte: Universidade Estadual Paulista Publicador: Universidade Estadual Paulista
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
57.92868%
This study evaluated the photodynamic inactivation (PDI) mediated by Photodithazine® (PDZ) against 15 clinical isolates of Candida albicans, Candida glabrata and Candida tropicalis. Each isolate, in planktonic and biofilm form, was exposed to PDI by assessing a range of PDZ concentrations and light emitting diode fluences. Cell survival of the planktonic suspensions was determined by colony forming units (CFU ml-1). The antifungal effects of PDI against biofilms were evaluated by CFU ml-1 and metabolic assay. Data were analyzed by non-parametric tests (α = 0.05). Regardless of the species, PDI promoted a significant viability reduction of planktonic yeasts. The highest reduction in cell viability of the biofilms was equivalent to 0.9 log10 (CFU ml-1) for C. albicans, while 1.4 and 1.5 log10 reductions were obtained for C. tropicalis and C. glabrata, respectively. PDI reduced the metabolic activity of biofilms by 62.1, 76.0, and 76.9% for C. albicans, C. tropicalis, and C. glabrata, respectively. PDZ-mediated PDI promoted significant reduction in the viability of Candida isolates. © 2013 Taylor & Francis.

Photodynamic inactivation of microrganisms with multicharged phythalocyanines; Inativação fotodinâmica de microrganismos com ftalocianinas multicarregadas

Rocha, Deisy Mara Gomes da Cruz
Fonte: Universidade de Aveiro Publicador: Universidade de Aveiro
Tipo: Dissertação de Mestrado
ENG
Relevância na Pesquisa
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The main goal of this work was to synthesize and characterize new phthalocyanines (Pc) for the photodynamic inactivation of microorganisms. For this, the synthesis of a new family of zinc(II)Pc tetra- and octa- substituted at the peripheral positions was attempt. The compounds were characterized by mass spectrometry and NMR spectroscopy. The inactivation efficiency of six Zinc(II) Pc, tetra- octa- and hexadeca-substituted with DMAP groups was evaluated against a recombinant bioluminescent strain of Escherichia coli in its planktonic form. The experiments were carried out at a concentration of 20 μM of photosensitizer, and either red or white light, with a fluency rate of 150 mW cm-2 as energy source. Assays of photodynamic inactivation of biofilms of the bioluminescent strain were also conducted with red light and the PS that demonstrated better performance in the photodynamic inactivation of free cells. The generation of 1O2, the solubility, fluorescence quantum yield, photostability and cellular uptake were also assessed. Pc 4 and 5 presented the highest inactivation efficiency in the planktonic form of the bioluminescent E.coli, causing reductions of 4 log in their light emission. These molecules were however much less effective against biofilms of the same strain...

Inativação fotodinâmica de endósporos bacterianos: aplicação de alta pressão como coadjuvante na ligação de fotossensibilizador; Photodynamic inactivation of bacterial endospores: high pressure processing as an assistant in the photosensitizer binding

Couceiro, Joana Duarte Baptista
Fonte: Universidade de Aveiro Publicador: Universidade de Aveiro
Tipo: Dissertação de Mestrado
POR
Relevância na Pesquisa
48.640947%
Os endósporos bacterianos representam riscos significativos em muitas atividades humanas, pelo que é fundamental descobrir formas de inativar estas estruturas. A terapia fotodinâmica (PDT) têm-se revelado uma alternativa promissora para inativar microrganismos patogénicos. Com este trabalho pretendeu-se avaliar o efeito da alta pressão como coadjuvante do efeito fotodinâmico, na inativação de endósporos de Bacillus cereus, usados como modelo biológico de endósporos bacterianos. Endósporos de B. cereus foram preparados em meios de esporulação e conservados a -20 °C até à realização dos ensaios. Como fotossensibilizador (PS), utilizou-se uma porfirina tetracatiónica (Tetra-Py+-Me), aplicada nas concentrações de 5 e 20 M. Os endósporos foram incubados durante 30 min a 37 °C no escuro, na presença de PS, para permitir a adsorção do PS ao material do endósporo. A potência da luz branca usada na irradiação foi 1690 W.m-2. O efeito dos vários tratamentos foi avaliado por comparação dos resultados com os valores iniciais da concentração de endósporos viáveis na suspensão não tratada. As variáveis em estudo foram a concentração de PS, a pressão aplicada, a temperatura de incubação e o tempo de exposição à luz branca. Em cada experiência foram incluídos os seguintes controlos: controlo claro (exposto à luz sem PS)...

Photodynamic inactivation of Escherichia coli by methylene blue and malachite green under red LED light

Hasegawa,Guilherme K. F.; Morais,Josmaria Lopes de; Soares,Marlene; Freitas,Adriane M. de
Fonte: Instituto de Pesquisas Ambientais em Bacias Hidrográficas Publicador: Instituto de Pesquisas Ambientais em Bacias Hidrográficas
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/06/2015 EN
Relevância na Pesquisa
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This study assessed the effectiveness of methylene blue (MB) and malachite green (MG) on photodynamic inactivation (PDI) of Escherichia coli. The photosensitizers methylene blue (1000 (mol L-1) and malachite green (250 (mol L-1) were activated with a red light-emitting diode (LED) lamp ((max = 636 nm). Bacterial suspensions containing 106 CFU mL-1 were irradiated for 5, 10 and 15 minutes (energy density = 119.9 J cm-2, 223.9 J cm-2 and 335.8 J cm-2, respectively). The following experimental conditions were performed for each photosensitizer: no light irradiation or photosensitizer, irradiation only, photosensitizer only or irradiation in the presence of a photosensitizer. Next, serial dilutions were prepared and seeded onto PCA medium for the determination of the number of colony-forming units per milliliter (CFU mL-1). The results were subjected to analysis of variance (ANOVA) and Tukey test (P<0.05). Photodynamic inactivation using MB and MG was effective in reducing the number of E. coli. Malachite green (250 µmol L-1) photosensitization was able to achieve reductions of over 89% in the viable counts after 15 min of irradiation and methylene blue (1000 µmol L-1), at the same conditions of irradiation, showed a rate growth inhibition of 94.6%. The red LED light used has proven to be effective in the photosensitizing dyes and proved a good alternative to conventional light sources such as laser.

Photodynamic inactivation of infectivity of human immunodeficiency virus and other enveloped viruses using hypericin and rose bengal: inhibition of fusion and syncytia formation.

Lenard, J; Rabson, A; Vanderoef, R
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em 01/01/1993 EN
Relevância na Pesquisa
48.188374%
The mechanism of the antiviral activity of hypericin was characterized and compared with that of rose bengal. Both compounds inactivate enveloped (but not unenveloped) viruses upon illumination by visible light. Human immunodeficiency and vesicular stomatitis viruses were photodynamically inactivated by both dyes at nanomolar concentrations. Photodynamic inactivation of fusion (hemolysis) by vesicular stomatitis, influenza, and Sendai viruses was induced by both dyes under similar conditions (e.g., I50 = 20-50 nM for vesicular stomatitis virus), suggesting that loss of infectivity resulted from inactivation of fusion. Syncytium formation, between cells activated to express human immunodeficiency virus gp120 on their surfaces and CD4+ cells, was inhibited by illumination in the presence of 1 microM hypericin. Hypericin and rose bengal thus exert similar virucidal effects. Both presumably act by the same mechanism--namely, the inactivation of the viral fusion function by singlet oxygen produced upon illumination. The implications of this photodynamic antiviral action for the potential therapeutic usefulness of both hypericin and rose bengal are discussed.

Photodynamic Inactivation of Enteroviruses

Wallis, Craig; Melnick, Joseph L.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /01/1965 EN
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Wallis, Craig (Baylor University College of Medicine, Houston, Tex.), and Joseph L. Melnick. Photodynamic inactivation of enteroviruses. J. Bacteriol. 89:41–46. 1965.—Enteroviruses are usually resistant to photodynamic inactivation, but they can be rendered completely photosensitive to proflavine at pH 9 to 10, if they are first purified by filtration through an anion resin. In addition, if enteroviruses are grown in cells maintained in a salt-glucose medium, they can be photosensitized. Of 38 enteroviruses tested, 10 were rendered completely photosensitive to proflavine, or toluidine blue, or both, and the remaining 28 viruses were sensitized, but to a lesser degree. The binding of dye to the virus can be reversed by lowering the pH.

Use of Merocyanine 540 for Photodynamic Inactivation of Staphylococcus aureus Planktonic and Biofilm Cells

Lin, Hsiao-Yin; Chen, Chin-Tin; Huang, Ching-Tsan
Fonte: American Society for Microbiology Publicador: American Society for Microbiology
Tipo: Artigo de Revista Científica
Publicado em /11/2004 EN
Relevância na Pesquisa
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Photodynamic inactivation of Staphylococcus aureus planktonic and biofilm cells by a phtotosensitizer, merocyanine 540 (MC 540), was investigated. For the planktonic experiments, MC 540 binding efficiency to bacterial cells was found to increase with both increasing MC 540 concentration and increasing incubation time, but the binding became saturated following 10 min of incubation. The antimicrobial activity was enhanced with an increasing light dose, but an increase in the light dose could not further improve the antimicrobial activity if the maximum excitation level attainable was less than the necessary minimum threshold level. Complete inactivation was achieved when the excitation level of MC 540 was somewhere above the threshold level. The relationship between antimicrobial activity and the excitation level of MC 540 revealed that the more MC 540 was excited, the more S. aureus cells were killed. For the biofilm experiments, the antimicrobial activity was enhanced with an increase in the light dose. No viable cells were detected when organisms were exposed to 15 μg of MC 540 per ml and a light dose of 600 J/cm2 or to 20 μg of MC 540 per ml and a light dose of 450 J/cm2. A quantitative analysis of MC 540 bound to biofilms was also performed...

Susceptibility of Cryptococcus neoformans to Photodynamic Inactivation Is Associated with Cell Wall Integrity▿

Fuchs, Beth Burgwyn; Tegos, George P.; Hamblin, Michael R.; Mylonakis, Eleftherios
Fonte: American Society for Microbiology Publicador: American Society for Microbiology
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
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Photodynamic therapy is a rapidly developing antimicrobial technology which combines a nontoxic photoactivatable dye or photosensitizer with harmless visible light of the correct wavelength to excite the dye to its reactive triplet state to generate reactive oxygen species toxic to cells. In this report we present evidence that the fungal pathogen Cryptococcus neoformans is susceptible to photodynamic inactivation by use of a polycationic conjugate of polyethyleneimine and the photosensitizer chlorin(e6). A C. neoformans rom2 mutant, with a mutation involving a putative Rho1 guanyl nucleotide exchange factor that is part of the protein kinase C-cell wall integrity pathway, demonstrated a compromised cell wall and less (1,3)β-d glucan than the wild-type strain and increased accumulation of PEI-ce6 as assessed by fluorescence uptake and confocal microscopy. Interestingly, C. neoformans rom2 was hypersusceptible to photodynamic inactivation and coincubation of wild-type C. neoformans strain KN99α with caspofungin-enhanced photoinactivation. These studies demonstrated that C. neoformans is sensitive to photodynamic therapy and illustrated the significance of cell wall integrity in microbial susceptibility to antimicrobial photodynamic inactivation.

Optical method for monitoring of photodynamic inactivation of bacteria

Calin, Mihaela Antonina; Ion, Rodica Mariana
Fonte: Springer Netherlands Publicador: Springer Netherlands
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
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Photodynamic inactivation is a new promising approach to treat bacterial infections. Usually, the evaluation of the efficacy of this method is done through time-consuming and labor-intensive microbiological test methods. This paper describes the development and implementation of an optical method to evaluate the photodynamic inactivation of bacteria based on non-invasive diffuse reflectance measurements. Five Staphylococcus aureus cultures and 15 mice have been used in this study. A skin lesion was created on the back of all animals, and it was contaminated with S. aureus (5.16 ± 0.013 log CFU/ml). Toluidine Blue O (c = 8.67 × 10 − 3 M) has been used as a photosensitiser agent. The bacterial cultures and animals were exposed to laser radiation (λ = 635 nm, P = 15 mW, DE = 8.654 J/cm2) for 20 min. The photodynamic inactivation of bacteria was monitored by acquiring the wounds’ reflection spectra at different time points and by microbiological exams on the bioptical material. The good correlation between the diffuse reflectance and colony-forming units demonstrates the value of this optical method based on diffuse reflectance measurements as a rapid technique to monitor photodynamic bacterial inactivation.

Photodynamic Inactivation of Mammalian Viruses and Bacteriophages

Costa, Liliana; Faustino, Maria Amparo F.; Neves, Maria Graça P. M. S.; Cunha, Ângela; Almeida, Adelaide
Fonte: MDPI Publicador: MDPI
Tipo: Artigo de Revista Científica
Publicado em 26/06/2012 EN
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Photodynamic inactivation (PDI) has been used to inactivate microorganisms through the use of photosensitizers. The inactivation of mammalian viruses and bacteriophages by photosensitization has been applied with success since the first decades of the last century. Due to the fact that mammalian viruses are known to pose a threat to public health and that bacteriophages are frequently used as models of mammalian viruses, it is important to know and understand the mechanisms and photodynamic procedures involved in their photoinactivation. The aim of this review is to (i) summarize the main approaches developed until now for the photodynamic inactivation of bacteriophages and mammalian viruses and, (ii) discuss and compare the present state of the art of mammalian viruses PDI with phage photoinactivation, with special focus on the most relevant mechanisms, molecular targets and factors affecting the viral inactivation process.

A Comprehensive Tutorial on In Vitro Characterization of New Photosensitizers for Photodynamic Antitumor Therapy and Photodynamic Inactivation of Microorganisms

Kiesslich, Tobias; Gollmer, Anita; Maisch, Tim; Berneburg, Mark; Plaetzer, Kristjan
Fonte: Hindawi Publishing Corporation Publicador: Hindawi Publishing Corporation
Tipo: Artigo de Revista Científica
EN
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In vitro research performed on eukaryotic or prokaryotic cell cultures usually represents the initial step for characterization of a novel photosensitizer (PS) intended for application in photodynamic therapy (PDT) of cancer or photodynamic inactivation (PDI) of microorganisms. Although many experimental steps of PS testing make use of the wide spectrum of methods readily employed in cell biology, special aspects of working with photoactive substances, such as the autofluorescence of the PS molecule or the requirement of light protection, need to be considered when performing in vitro experiments in PDT/PDI. This tutorial represents a comprehensive collection of operative instructions, by which, based on photochemical and photophysical properties of a PS, its uptake into cells, the intracellular localization and photodynamic action in both tumor cells and microorganisms novel photoactive molecules may be characterized for their suitability for PDT/PDI. Furthermore, it shall stimulate the efforts to expand the convincing benefits of photodynamic therapy and photodynamic inactivation within both established and new fields of applications and motivate scientists of all disciplines to get involved in photodynamic research.

Evaluation of gene expression SAP5, LIP9, and PLB2 of candida albicans biofilms after photodynamic inactivation

Freire, Fernanda; Barros, Patricia Pimentel de; Avila, Damara da Silva; Back Brito, Graziella Nuernberg; Junqueira, Juliana Campos; Cardoso Jorge, Antonio Olavo
Fonte: Springer Publicador: Springer
Tipo: Artigo de Revista Científica Formato: 1511-1518
ENG
Relevância na Pesquisa
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP); Processo FAPESP: 2012/09188-0; With the increasing number of strains of Candida ssp. resistant to antifungal agents, the accomplishment of researches that evaluate the effects of new therapeutic methods, like photodynamic inactivation (PDI), becomes important and necessary. Thus, the objective of this study was to verify the effects of the PDI on Candida albicans biofilms, evaluating their effects on the expression of the gene hydrolytic enzymes aspartyl proteinase (SAP5), lipase (LIP9), and phospholipase (PLB2). Clinical strains of C. albicans (n = 9) isolated from patient bearers of the virus HIV and a pattern strain ATCC 18804 were used. The quantification of gene expression was related to the production of hydrolytic enzymes using the quantitative polymerase chain reaction (qPCR) assay. For PDI, we used laser-aluminum-gallium arsenide low power (red visible, 660 nm) as a light source and the methylene blue at 300 mu M as a photosensitizer. We assessed two experimental groups for each strain: (a) PDI: sensitization with methylene blue and laser irradiation and (b) control: without sensitization with methylene blue and light absence. The PDI decreased gene expression in 60 % of samples for gene SAP5 and 50 % of the samples decreased expression of LIP9 and PLB2. When we compared the expression profile for of each gene between the treated and control group...

Impact of crosslinking/riboflavin-UVA-photodynamic inactivation on viability, apoptosis and activation of human keratocytes in vitro

Stachon, Tanja; Wang, Jiong; Song, Xufei; Langenbucher, Achim; Seitz, Berthold; Szentmáry, Nóra
Fonte: Editorial Department of Journal of Biomedical Research Publicador: Editorial Department of Journal of Biomedical Research
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
48.48808%
Riboflavin-UVA photodynamic inactivation is a potential treatment alternative in therapy resistant infectious keratitis. The purpose of our study was to determine the impact of riboflavin-UVA photodynamic inactivation on viability, apoptosis and activation of human keratocytes in vitro. Primary human keratocytes were isolated from human corneal buttons and cultured in DMEM/Ham's F12 medium supplemented with 10% fetal calf serum. Keratocytes underwent UVA light illumination (375 nm) for 4.10 minutes (2 J/cm2) during exposure to different concentrations of riboflavin. Twenty-four hours after treatment, cell viability was evaluated photometrically, whereas apoptosis, CD34 and alpha-smooth muscle actin (α-SMA) expression were assessed using flow cytometry. We did not detect significant changes in cell viability, apoptosis, CD34 and α-SMA expression in groups only treated with riboflavin or UVA light. In the group treated with riboflavin-UVA-photodynamic inactivation, viability of keratocytes decreased significantly at 0.1% riboflavin (P<0.01) while the percentage of CD34 (P<0.01 for both 0.05% and 0.1% riboflavin) and alpha-SMA positive keratocytes (P<0.01 and P<0.05 for 0.05% and 0.1% riboflavin, respectively) increased significantly compared to the controls. There was no significant change in the percentage of apoptotic keratocytes compared to controls at any of the used riboflavin concentrations (P = 0.09 and P = 0.13). We concluded that riboflavin-UVA-photodynamic-inactivation decreases viability of myofibroblastic transformation and multipotent haematopoietic stem cell transformation; however...