Detection of Bacterial Endospores In Soil By Terbium Fluorescence |
Sporeformation is a survival mechanism of microorganisms when facing unfavorableenvironmental conditions resulting in “dormant” states. We investigated theoccurrence of bacterial endospores in soils from various locations includinggrasslands (pasture, meadow), allotment gardens, and forests, as well asfluvial sediments. Bacterial spores are characterized by their high content ofdipicolinic acid (DPA). In the presence of terbium, DPA forms a complex showinga distinctive photoluminescence spectrum. DPA was released from soil bymicrowaving or autoclaving. The addition of aluminium chloride reduced signalquenching by interfering compounds such as phosphate. The highest spore content(up to 109 spores per gram of dry soil) was found in grassland soils. Sporecontent is related to soil type, to soil depth, and to soil carbon-to-nitrogenratio. Our study might provide a basis for the detection of “hot spots” ofbacterial spores in soil.