New Method for Estimating Bacterial Abundances in Natural Samples using Sublimation

摘要

We have developed a new method based on the sublimation of adenine from Escherichia coli to estimate bacterial cell counts in natural samples. To demonstrate this technique, several types of natural samples including beach sand, seawater, deep-sea sediment, and two soil samples from the Atacama Desert were heated to a temperature of 500 degrees C for several seconds under reduced pressure. The sublimate was collected on a cold finger and the aqount of adenine released from the samples then determined by high performance liquid chromatography (HPLC) with W absorbance detection. Based on the total amount of adenine recovered from DNA and RNA in these samples, we estimated bacterial cell counts ranging from approx. 10(sub 5) to l0(sub 9) E. coli cell equivalents per gram (ECE/g). For most of these samples, the sublimation based cell counts were in agreement with total bacterial counts obtained by traditional DAPI staining.