RESUMEN
We synthesised a new type of photochromic tungsten oxide nanoparticles, analysed their photocatalytic activity and carried out a thorough analysis of their effect on prokaryotic and eukaryotic organisms. Ultrasmall hydrated tungsten oxide nanoparticles were prepared by means of hydrothermal treatment of tungstic acid in the presence of polyvinylpyrrolidone as a template, stabiliser and growth regulator. Tungstic acid was synthesised through an ion-exchange method using sodium tungstate solution and a strongly acidic cation exchange resin. Upon illumination, photochromic nanoparticles of WO3 were shown to increase greatly their toxicity against both bacterial (both gram-positive and gram-negative - P. aeruginosa, E. coli and S. aureus) and mammalian cells (primary mouse embryonic fibroblasts); under the same conditions, fungi (C. albicans) were less sensitive to the action of tungsten oxide nanoparticles. UV irradiation of primary mouse fibroblasts in the presence of WO3 nanoparticles demonstrated a time- and dose-dependent toxic effect, the latter leading to a significant decrease in dehydrogenase activity and an increase in the number of dead cells. WO3 nanoparticles were photocatalytically active under both UV light and even diffused daylight filtered through a window glass, leading to indigo carmine organic dye discolouration. The obtained experimental data not only show good prospects for biomedical applications of tungsten trioxide, but also demonstrate the need for clear control of biosafety when it is used in various household materials and appliances.
Asunto(s)
Nanopartículas del Metal/química , Óxidos/química , Tungsteno/química , Animales , Catálisis , Línea Celular , Supervivencia Celular/efectos de los fármacos , Supervivencia Celular/efectos de la radiación , Colorantes/química , Hongos/efectos de los fármacos , Hongos/efectos de la radiación , Bacterias Gramnegativas/efectos de los fármacos , Bacterias Gramnegativas/efectos de la radiación , Bacterias Grampositivas/efectos de los fármacos , Bacterias Grampositivas/efectos de la radiación , Nanopartículas del Metal/toxicidad , Ratones , Microscopía Fluorescente , Oxidorreductasas/metabolismo , Rayos UltravioletaRESUMEN
The biofilm formation of three P. aeruginosa collection strains, isolated from human body, was investigated in stationary system on glass. It was shown, that biofilm formation of these microorganisms has three stages: initial formation, the further partial degradation and repeated accumulation. The intensity of biofilm formation correlates with survival rate of microorganisms in its structure that may be estimated by means of the "washout" method. The strain differences are typical of P. aeruginosa biofilm formation and determine further regularities of its development.
Asunto(s)
Biopelículas/crecimiento & desarrollo , Pseudomonas aeruginosa/crecimiento & desarrollo , Bancos de Muestras Biológicas , Adhesión Celular , Recuento de Colonia Microbiana , Humanos , Viabilidad Microbiana , Pseudomonas aeruginosa/clasificación , Pseudomonas aeruginosa/aislamiento & purificación , Especificidad de la Especie , UcraniaRESUMEN
The ability of exopolysaccharides of Pseudomonas aureofaciens strains UKM B-111 and UKM B-306, components of insectofungicidal preparation Gaupsin, to influence the process of tumour formation caused by Agrobacterium tumefaciens. Bacterial polysaccharides, obtained on Kozer medium with glucose (possible alginates) blocked agrobacterium cell adhesion by 29-49%. Those obtained on the medium with sucrose polysaccharides (possible levans) by 30-75% inhibit later stages of tumour formation. The paper is presented in Ukrainian.
