RESUMO
Phase-contrast microscopy coupled with image analysis has been used to study the germination of single spores of Clostridium botulinum and to investigate the variation of germination lag of individual spores in a population (biovariability). The experiment was repeated at five different temperatures between 20 degrees C and 37 degrees C to look at the effect of temperature on the biovaribility of the spore germination. Data analysis shows that the germination lag distribution is skewed, with a tail, and that its shape is affected by the temperature. The origin of this biovariability is not exactly known, but could be due to a distribution of characteristics (e.g. permeabilities) or molecules (e.g. lytic enzymes) in the spore population. The method developed in this study will help us to describe and better understand the kinetics of spore germination and how this is influence by different environmental factors such as temperature and other factors that influence germination.