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El trabajo realizado trata d ela traslacion de un algoritmo genetico hacia hardware mediante el d... more El trabajo realizado trata d ela traslacion de un algoritmo genetico hacia hardware mediante el diseno y la simulacion de diversos sitemas paralelos. A partir de los precedentes que existen de sinteis como cirucitos digitales de herramientas del entorno de inteligencia Artificial (como las redes neuronales y el control borroso) se plantea el analisis de un sistema que realice las operaciones de un algoritmo genetico, usando su descripcion en lenguaje VHDL conel doble proposito de su simulaciony su posterior sintesis. Se disenan los modulos precisos para la implementaciond el sistema (operadores de inicializacion, crossover, mutacion, reporduccion y actualizacion) junto con una funcion de fitness y una unidad de control. El conjunto de elementos resuleve el algoritmo genetico en hardware. Se somete al sistema a una serie de simulaciones de las que se concluye que seria deseable, con el fin de mejorar su funcionamiento, paralelizar el sistema usando un modelo SIMD. Se disenan distinto...
Food Microbiology, 2019
The susceptibility of four L. monocytogenes isolates from pork to sodium hypochlorite (SHY) and b... more The susceptibility of four L. monocytogenes isolates from pork to sodium hypochlorite (SHY) and benzalkonium chloride (BZK) was tested. Minimum inhibitory concentration (MIC) values of 3,500 ppm (SHY), or between 3 ppm and 13 ppm (BZK), were found. Minimum bactericidal concentration (MBC) values ranged from 3,500 ppm to 4,500 ppm (SHY), and from 3 ppm to 14 ppm (BZK). The effect of SHY and BZK on the architecture and cellular viability of 24-hourold biofilms formed by such strains on polystyrene was determined through confocal laser scanning microscopy (CLSM) in conjunction with fluorescent dyes for live cells (SYTO 9) and dead cells (propidium iodide). Strains were able to form biofilm (biovolume values in the observation field of 14,161 µm 2 ranged between 103,928.3 ± 6,730.2 µm 3 and 276,030.9 ± 42,291.9 µm 3). Treatment of biofilms for 10 minutes with SHY (1MIC or 1.5MIC) or BZK (0.5MIC, 1MIC or 1.5MIC) decreased the biovolume of live (potentially dangerous) cells. SHY reduced the cellular viability of biofilms by more than 90%. On the other hand, BZK was able to remove most biofilm mass (live and dead cells), but decreased cellular viability only to a lesser extent, this suggesting strong biofilm detachment and dissemination of live cells.
Food Microbiology, 2017
The effect of sub-minimum inhibitory concentrations (sub-MICs) of three biocides (benzalkonium ch... more The effect of sub-minimum inhibitory concentrations (sub-MICs) of three biocides (benzalkonium chloride [BZK], trisodium phosphate [TSP] and sodium hypochlorite [SHY]) upon the architecture and viability of the biofilms formed by a methicillin-resistant Staphylococcus aureus strain of food origin (MRSA 48a) was investigated. Images were examined through confocal laser scanning microscopy (CLSM) after staining with SYTO9 and propidium iodide. Sub-MICs of BZK or TSP reduced the ability of MRSA to produce biofilm. In contrast, the presence of sub-MICs of SHY enhanced the biofilm-forming ability of MRSA when cells had undergone previous adaptation to this compound (biovolume in the observation field was 137,785.31 ± 47,682.79 µm 3 for biofilms formed in the presence of SHY, and 70,204.13 ± 31,603.98 µm 3 in the absence of biocides; P < 0.05). The largest amount of live (green stained) cells (P < 0.05) was observed in biofilms grown in the presence of SHY relative to the other conditions tested (58,999.75 ± 55,312.37 µm 3 vs 31,976.29 ± 38,594.98 µm 3). Findings from the present work constitute the first report of biofilm production by MRSA being induced by sub-inhibitory concentrations of SHY. The data suggest that repeated use of SHY at low concentrations could represent a public health risk.
Food Control, 2014
Ten multi-drug resistant Salmonella enterica isolates belonging to ten different serotypes were e... more Ten multi-drug resistant Salmonella enterica isolates belonging to ten different serotypes were exposed to increasing sub-inhibitory concentrations of three biocides widely used in food industry facilities (trisodium phosphate, sodium nitrite, or sodium hypochlorite). Cultures were tested, before and after exposure to biocides, against 31 antibiotics of clinical significance by means of a standard disk-diffusion technique (CLSI). Exposed cultures displayed reduced susceptibility to a range of antibiotics, as compared with not exposed cultures. The impact of biocide exposure on reduced susceptibility to antibiotics was dependent on the Salmonella strain and the antibiotic family tested, susceptibility to aminoglycosides and cephalosporins being the most strongly affected. Results in the present study suggest that extensive use of biocides at sub-lethal concentrations could contribute to the emergence of antibiotic resistance in multi-drug resistant Salmonella enterica strains and therefore represent a public health risk. The intraspecific differences observed in antibiotic susceptibility underline the need to screen a wide range of strains.
unileon.es
... José Ramón Rodríguez Pérez (1), Félix Riesco Peláez (1), Carlos José Álvarez López (2) ... lo... more ... José Ramón Rodríguez Pérez (1), Félix Riesco Peláez (1), Carlos José Álvarez López (2) ... los términos municipales que el Consejo Regulador considera aptos para la producción de uvas: Arganza, Bembibre, Borrenes, Cabañas Raras, Cacabelos, Camponaraya, Carracedelo ...
Applied and Environmental Microbiology, 2013
Escherichia coli ATCC 12806 was exposed to increasing subinhibitory concentrations of three bioci... more Escherichia coli ATCC 12806 was exposed to increasing subinhibitory concentrations of three biocides widely used in food industry facilities: trisodium phosphate (TSP), sodium nitrite (SNI), and sodium hypochlorite (SHY). The cultures exhibited an acquired tolerance to biocides (especially to SNI and SHY) after exposure to such compounds. E. coli produced biofilms (as observed by confocal laser scanning microscopy) on polystyrene microtiter plates. Previous adaptation to SNI or SHY enhanced the formation of biofilms (with an increase in biovolume and surface coverage) both in the absence and in the presence (MIC/2) of such compounds. TSP reduced the ability of E. coli to produce biofilms. The concentration of suspended cells in the culture broth in contact with the polystyrene surfaces did not influence the biofilm structure. The increase in cell surface hydrophobicity (assessed by a test of microbial adhesion to solvents) after contact with SNI or SHY appeared to be associated with...
El trabajo realizado trata d ela traslacion de un algoritmo genetico hacia hardware mediante el d... more El trabajo realizado trata d ela traslacion de un algoritmo genetico hacia hardware mediante el diseno y la simulacion de diversos sitemas paralelos. A partir de los precedentes que existen de sinteis como cirucitos digitales de herramientas del entorno de inteligencia Artificial (como las redes neuronales y el control borroso) se plantea el analisis de un sistema que realice las operaciones de un algoritmo genetico, usando su descripcion en lenguaje VHDL conel doble proposito de su simulaciony su posterior sintesis. Se disenan los modulos precisos para la implementaciond el sistema (operadores de inicializacion, crossover, mutacion, reporduccion y actualizacion) junto con una funcion de fitness y una unidad de control. El conjunto de elementos resuleve el algoritmo genetico en hardware. Se somete al sistema a una serie de simulaciones de las que se concluye que seria deseable, con el fin de mejorar su funcionamiento, paralelizar el sistema usando un modelo SIMD. Se disenan distinto...
Food Microbiology, 2019
The susceptibility of four L. monocytogenes isolates from pork to sodium hypochlorite (SHY) and b... more The susceptibility of four L. monocytogenes isolates from pork to sodium hypochlorite (SHY) and benzalkonium chloride (BZK) was tested. Minimum inhibitory concentration (MIC) values of 3,500 ppm (SHY), or between 3 ppm and 13 ppm (BZK), were found. Minimum bactericidal concentration (MBC) values ranged from 3,500 ppm to 4,500 ppm (SHY), and from 3 ppm to 14 ppm (BZK). The effect of SHY and BZK on the architecture and cellular viability of 24-hourold biofilms formed by such strains on polystyrene was determined through confocal laser scanning microscopy (CLSM) in conjunction with fluorescent dyes for live cells (SYTO 9) and dead cells (propidium iodide). Strains were able to form biofilm (biovolume values in the observation field of 14,161 µm 2 ranged between 103,928.3 ± 6,730.2 µm 3 and 276,030.9 ± 42,291.9 µm 3). Treatment of biofilms for 10 minutes with SHY (1MIC or 1.5MIC) or BZK (0.5MIC, 1MIC or 1.5MIC) decreased the biovolume of live (potentially dangerous) cells. SHY reduced the cellular viability of biofilms by more than 90%. On the other hand, BZK was able to remove most biofilm mass (live and dead cells), but decreased cellular viability only to a lesser extent, this suggesting strong biofilm detachment and dissemination of live cells.
Food Microbiology, 2017
The effect of sub-minimum inhibitory concentrations (sub-MICs) of three biocides (benzalkonium ch... more The effect of sub-minimum inhibitory concentrations (sub-MICs) of three biocides (benzalkonium chloride [BZK], trisodium phosphate [TSP] and sodium hypochlorite [SHY]) upon the architecture and viability of the biofilms formed by a methicillin-resistant Staphylococcus aureus strain of food origin (MRSA 48a) was investigated. Images were examined through confocal laser scanning microscopy (CLSM) after staining with SYTO9 and propidium iodide. Sub-MICs of BZK or TSP reduced the ability of MRSA to produce biofilm. In contrast, the presence of sub-MICs of SHY enhanced the biofilm-forming ability of MRSA when cells had undergone previous adaptation to this compound (biovolume in the observation field was 137,785.31 ± 47,682.79 µm 3 for biofilms formed in the presence of SHY, and 70,204.13 ± 31,603.98 µm 3 in the absence of biocides; P < 0.05). The largest amount of live (green stained) cells (P < 0.05) was observed in biofilms grown in the presence of SHY relative to the other conditions tested (58,999.75 ± 55,312.37 µm 3 vs 31,976.29 ± 38,594.98 µm 3). Findings from the present work constitute the first report of biofilm production by MRSA being induced by sub-inhibitory concentrations of SHY. The data suggest that repeated use of SHY at low concentrations could represent a public health risk.
Food Control, 2014
Ten multi-drug resistant Salmonella enterica isolates belonging to ten different serotypes were e... more Ten multi-drug resistant Salmonella enterica isolates belonging to ten different serotypes were exposed to increasing sub-inhibitory concentrations of three biocides widely used in food industry facilities (trisodium phosphate, sodium nitrite, or sodium hypochlorite). Cultures were tested, before and after exposure to biocides, against 31 antibiotics of clinical significance by means of a standard disk-diffusion technique (CLSI). Exposed cultures displayed reduced susceptibility to a range of antibiotics, as compared with not exposed cultures. The impact of biocide exposure on reduced susceptibility to antibiotics was dependent on the Salmonella strain and the antibiotic family tested, susceptibility to aminoglycosides and cephalosporins being the most strongly affected. Results in the present study suggest that extensive use of biocides at sub-lethal concentrations could contribute to the emergence of antibiotic resistance in multi-drug resistant Salmonella enterica strains and therefore represent a public health risk. The intraspecific differences observed in antibiotic susceptibility underline the need to screen a wide range of strains.
unileon.es
... José Ramón Rodríguez Pérez (1), Félix Riesco Peláez (1), Carlos José Álvarez López (2) ... lo... more ... José Ramón Rodríguez Pérez (1), Félix Riesco Peláez (1), Carlos José Álvarez López (2) ... los términos municipales que el Consejo Regulador considera aptos para la producción de uvas: Arganza, Bembibre, Borrenes, Cabañas Raras, Cacabelos, Camponaraya, Carracedelo ...
Applied and Environmental Microbiology, 2013
Escherichia coli ATCC 12806 was exposed to increasing subinhibitory concentrations of three bioci... more Escherichia coli ATCC 12806 was exposed to increasing subinhibitory concentrations of three biocides widely used in food industry facilities: trisodium phosphate (TSP), sodium nitrite (SNI), and sodium hypochlorite (SHY). The cultures exhibited an acquired tolerance to biocides (especially to SNI and SHY) after exposure to such compounds. E. coli produced biofilms (as observed by confocal laser scanning microscopy) on polystyrene microtiter plates. Previous adaptation to SNI or SHY enhanced the formation of biofilms (with an increase in biovolume and surface coverage) both in the absence and in the presence (MIC/2) of such compounds. TSP reduced the ability of E. coli to produce biofilms. The concentration of suspended cells in the culture broth in contact with the polystyrene surfaces did not influence the biofilm structure. The increase in cell surface hydrophobicity (assessed by a test of microbial adhesion to solvents) after contact with SNI or SHY appeared to be associated with...