Effect of drying treatment on the respiratory quinone profile in soil

Recently, the analysis of the microbial community structure in soil has received a great deal of attention. Various analytical methods based on biomarkers have been developed: 16S-rDNA, total DNA, phospholipid fatty acids, ergosterols, muramic acids, etc. (Tunlid and White 1992; Carter and Lynch 1993). In a previous paper, we reported that respiratory quinones are useful biomarkers to characterize the microbial community structure in soil (Fujie et al. 1998). In these analyses, only fresh moist soils or frozen soils had been used as samples. However, the soil samples are generally stored in the dark after air drying in many research institutes and experimental stations. It was considered that the analysis of microbial communities in dried soil samples was not possible. In this paper, we observed that the drying of soils did not affect the proportions of quinone species in soil although the treatment decreased the amount of extracted quinones. These findings suggest that the analysis of the respiratory quinone profile of dried soils reflects the micro biota present in fresh moist soils before drying.