Brandes Ammann Andrea, Kölle Linda, Brandl Helmut
Institute of Evolutionary Biology and Environmental Studies (IEU), University of Zurich, Winterthurerstraße 190, CH-8057 Zurich, Switzerland.
Int J Microbiol. 2011;2011:435281. doi: 10.1155/2011/435281. Epub 2011 Jul 7.
Spore formation is a survival mechanism of microorganisms when facing unfavorable environmental conditions resulting in "dormant" states. We investigated the occurrence of bacterial endospores in soils from various locations including grasslands (pasture, meadow), allotment gardens, and forests, as well as fluvial sediments. Bacterial spores are characterized by their high content of dipicolinic acid (DPA). In the presence of terbium, DPA forms a complex showing a distinctive photoluminescence spectrum. DPA was released from soil by microwaving or autoclaving. The addition of aluminium chloride reduced signal quenching by interfering compounds such as phosphate. The highest spore content (up to 10(9) spores per gram of dry soil) was found in grassland soils. Spore content is related to soil type, to soil depth, and to soil carbon-to-nitrogen ratio. Our study might provide a basis for the detection of "hot spots" of bacterial spores in soil.
孢子形成是微生物在面临不利环境条件时进入“休眠”状态的一种生存机制。我们调查了包括草原（牧场、草地）、小菜园和森林土壤以及河流沉积物在内的不同地点土壤中细菌内生孢子的存在情况。细菌孢子的特征是含有高含量的吡啶二羧酸（DPA）。在铽存在的情况下，DPA形成一种具有独特光致发光光谱的复合物。通过微波处理或高压灭菌从土壤中释放出DPA。添加氯化铝可减少诸如磷酸盐等干扰化合物引起的信号猝灭。在草地土壤中发现了最高的孢子含量（每克干土高达10⁹个孢子）。孢子含量与土壤类型、土壤深度以及土壤碳氮比有关。我们的研究可能为检测土壤中细菌孢子的“热点”提供依据。
