RESUMO
Microcalorimetry is a highly sensitive experimental technique that determines heat changes in any process or transformation. All organisms produce heat due to their metabolism. Rate of heat flow is an adequate measure of metabolic activity of living beings and their component parts. Microorganisms produce small amounts of heat: 1-3 pW per cell. Although the heat produced by bacteria is very small, their exponential reproduction in a culture medium permits heat detection through microcalorimetry. A thermal conductivity calorimeter of the Calvet type was used. The inside of the calorimeter contains two stainless steel cells (experimental and reference) with a screw on Teflon cap with a hole in the centre. Experiments were carried out with final concentrations of the order of 10 , 10 , 10 and 10 UFC/ml. These were kept at a constant temperature of 309.65 K. The plot of change in heat voltage vs. time enables us to obtain the characteristic growth curve for each bacterial strain. Thermograms were analyzed mathematically allowing us to calculate the constant growth, generation time and the amount of heat exchanged over the culture time
Microcalorimetry is a highly sensitive experimental technique that determines heat changes in any process or transformation. All organisms produce heat due to their metabolism. Rate of heat flow is an adequate measure of metabolic activity of living beings and their component parts. Microorganisms produce small amounts of heat: 1-3 pW per cell. Although the heat produced by bacteria is very small, their exponential reproduction in a culture medium permits heat detection through microcalorimetry. A thermal conductivity calorimeter of the Calvet type was used. The inside of the calorimeter contains two stainless steel cells (experimental and reference) with a screw on Teflon cap with a hole in the centre. Experiments were carried out with final concentrations of the order of 10 , 10 , 10 and 10 UFC/ml. These were kept at a constant temperature of 309.65 K. The plot of change in heat voltage vs. time enables us to obtain the characteristic growth curve for each bacterial strain. Thermograms were analyzed mathematically allowing us to calculate the constant growth, generation time and the amount of heat exchanged over the culture time (AU)
La microcalorimetría es una técnica experimental que permite determinar con alta sensibilidad la energía expuesta como consecuencia de cualquier proceso o transformación. Todos los organismos producen calor debido a su metabolismo. La tasa de calor es una medida adecuada de la actividad metabólica de los organismos y sus partes constituyentes. Los microorganismos producen pequeñas cantidades de calor, del orden de 1-3 pW por célula. A pesar de la baja cantidad de calor producido por las bacterias, su exponencial replicación en un medio de cultivo permite su detección mediante microcalorimetría. Se ha utilizado un calorímetro de conducción calorífica tipo Calvet, en cuyo recinto interior se sitúan dos células (experimental y testigo) de acero inoxidable con tapón roscado de teflón perforado en el centro. Las experiencias se llevaron a cabo a concentraciones finales de 106, 105, 103 y 10 UFC/ml y se mantuvo una temperatura constante de 309,65 K. La representación de la diferencia de potencial calorífico frente al tiempo permite obtener las curvas de crecimiento características de cada bacteria. Los termogramas se analizaron matemáticamente permitiendo calcular la constante de crecimiento, el tiempo de generación y la cantidad de calor intercambiado
