RESUMEN

Ultrasound (US) combined with chemical agents could represent an effective method for decontaminating fruits and vegetables. This study aimed to evaluate the use of US (40 kHz for 5 min) alone or with 1% lactic acid (LA), 1% commercial detergent (DET), or 6 mg/L silver nanoparticles (AgNP, average diameter 100 nm) as an alternative treatment to 200 mg/L sodium dichloroisocyanurate for inactivating Salmonella enterica serovar Enteritidis present on cherry tomatoes. The interfacial tension between sanitizing solutions and bacterial adhesion was investigated. Sanitizers in solutions with DET and AgNP had lower surface tension. All treatments, except that with DET, reduced Salmonella Enteritidis by more than one logarithmic cycle. There was no significant difference between the mean values of log colony-forming units (CFU)/g reduction in all treatments. Transmission electron microscopy revealed the loss of the Salmonella Enteritidis capsule following treatment with US and with US + LA. Salmonella Enteritidis counts (2.29 log CFU/g) in cherry tomatoes were markedly reduced to safe levels by treatment with the combination of AgNP and US + LA (2.37 log CFU/g).

Asunto(s)

Desinfectantes/farmacología , Microbiología de Alimentos/métodos , Salmonella enteritidis/efectos de los fármacos , Solanum lycopersicum/microbiología , Ondas Ultrasónicas , Adhesión Bacteriana/efectos de los fármacos , Recuento de Colonia Microbiana , Detergentes/farmacología , Ácido Láctico/farmacología , Nanopartículas del Metal/química , Salmonella enteritidis/crecimiento & desarrollo , Plata/química , Plata/farmacología , Verduras/microbiología

RESUMEN

This study evaluated the parameters of oxidative stress and energy metabolism after the acute and long-term administration of gold nanoparticles (GNPs, 10 and 30 nm in diameter) in different organs of rats. Adult male Wistar rats received a single intraperitoneal injection or repeated injections (once daily for 28 days) of saline solution, GNPs-10 or GNPs-30. Twenty-four hours after the last administration, the animals were killed, and the liver, kidney, and heart were isolated for biochemical analysis. We demonstrated that acute administration of GNPs-30 increased the TBARS levels, and that GNPs-10 increased the carbonyl protein levels. The long-term administration of GNPs-10 increased the TBARS levels, and the carbonyl protein levels were increased by GNPs-30. Acute administration of GNPs-10 and GNPs-30 increased SOD activity. Long-term administration of GNPs-30 increased SOD activity. Acute administration of GNPs-10 decreased the activity of CAT, whereas long-term administration of GNP-10 and GNP-30 altered CAT activity randomly. Our results also demonstrated that acute GNPs-30 administration decreased energy metabolism, especially in the liver and heart. Long-term GNPs-10 administration increased energy metabolism in the liver and decreased energy metabolism in the kidney and heart, whereas long-term GNPs-30 administration increased energy metabolism in the heart. The results of our study are consistent with other studies conducted in our research group and reinforce the fact that GNPs can lead to oxidative damage, which is responsible for DNA damage and alterations in energy metabolism.

Asunto(s)

Metabolismo Energético/efectos de los fármacos , Oro/toxicidad , Corazón/efectos de los fármacos , Riñón/efectos de los fármacos , Hígado/efectos de los fármacos , Nanopartículas del Metal/toxicidad , Estrés Oxidativo/efectos de los fármacos , Animales , Biomarcadores/metabolismo , Ciclo del Ácido Cítrico/efectos de los fármacos , Sistemas de Liberación de Medicamentos/efectos adversos , Oro/administración & dosificación , Oro/análisis , Oro/química , Inyecciones Intraperitoneales , Riñón/química , Riñón/enzimología , Riñón/metabolismo , Hígado/química , Hígado/enzimología , Hígado/metabolismo , Masculino , Nanopartículas del Metal/administración & dosificación , Nanopartículas del Metal/química , Nanopartículas del Metal/ultraestructura , Mitocondrias/efectos de los fármacos , Mitocondrias/enzimología , Mitocondrias/metabolismo , Miocardio/química , Miocardio/enzimología , Miocardio/metabolismo , Tamaño de la Partícula , Carbonilación Proteica/efectos de los fármacos , Ratas Wistar , Distribución Tisular , Pruebas de Toxicidad Aguda , Pruebas de Toxicidad Subaguda , Toxicocinética

RESUMEN

Nanoparticulate silver has recently been reported as an effective antimicrobial agent. The aim of this clinical study was to investigate the potential changes on the oral microbiota of healthy individuals after controlled brushing with chlorhexidine- or silver-coated toothbrush bristles. Twenty-four healthy participants were enrolled in this investigation and randomly submitted to 3 interventions. All the participants received, in a crossover format, the following toothbrushing interventions: (i) chlorhexidine-coated bristles, (ii) silver-coated bristles, and (iii) conventional toothbrush (Control). All the interventions had a duration of 30 days. The DNA checkerboard hybridization method was used to identify and quantify up to 43 microbial species colonizing the supra- and subgingival biofilm. The supragingival samples presented higher genome counts than the subgingival samples (p < 0.0001). The total genome counts from the Control group showed the highest values, followed by the silver and chlorhexidine groups (p < 0.0001). After 4 weeks of brushing, the silver-coated and chlorhexidine-coated bristles were capable of reducing or maintaining lower levels of the bacterial counts of the putative periodontal pathogens Tanerella forsythia, Treponema denticola, and Porphyromonas gingivalis. Other major periodontal pathogens, such as Prevotella intermedia, Fusobacterium nucleatum, Prevotella nigrescens, and Parvimonas micra, were also detected at lower levels. The toothbrush bristles impregnated with silver nanoparticles reduced the total and individual genome count in the supra- and subgingival biofilm after 4 weeks of brushing. Chlorhexidine was not effective in reducing the total genome counts in both supra- or subgingival biofilm after 4 weeks of brushing. Chlorhexidine reduced the individual genome counts in the supragingival biofilm for most of the target species, including putative periodontal pathogens.

Asunto(s)

Biopelículas , Clorhexidina/química , Nanopartículas del Metal/química , Plata/química , Cepillado Dental , Adulto , Carga Bacteriana , ADN/química , Femenino , Fusobacterium nucleatum , Genoma Bacteriano , Voluntarios Sanos , Humanos , Masculino , Persona de Mediana Edad , Hibridación de Ácido Nucleico , Porphyromonas gingivalis , Prevotella intermedia , Prevotella nigrescens , Adulto Joven

RESUMEN

The formation of inclusion bodies (IBs) constitute a frequent event during the production of heterologous proteins in bacterial hosts. Although the mechanisms leading to their formation are not completely understood, empirical data have been exploited trying to predict the aggregation propensity of specific proteins while a great number of strategies have been developed to avoid the generation of IBs. However, in many cases, the formation of such aggregates can be considered an advantage for basic research as for protein production. In this review, we focus on this positive side of IBs formation in bacteria. We present a compilation on recent advances on the understanding of IBs formation and their utilization as a model to understand protein aggregation and to explore strategies to control this process. We include recent information about their composition and structure, their use as an attractive approach to produce low cost proteins and other promising applications in Biomedicine.