P425-TH SOIL BACTERIAL POPULATIONS AND PROCESSES IDENTIFIED USING BACTERIOHOPANEPOLYOL BIOMARKERS

The identification of bacteriohopanepolyol (BHP) biomarkers in soil samples from around the world has enabled the assessment of the dominant hopanoid-producing bacterial populations in the soil as well as a number of bacterially mediated soil processes without the need for DNA or RNA analysis of the samples. Bacteriohopanepolyols (BHPs; e.g. Fig. 1) are bacterial membrane compounds with a high degree of structural variability. They are analogous to steroids in eukaryotes and have been identified in over half of all bacteria tested for their presence. BHPs have a wide range of over 40 different functional groups on the side chain, with up to 6 being present in any structure and, with the possibility of methylation and unsaturation, over 100 individual structures have been identified (e.g. Fig. 1), some of which may be unique to specific bacteria groups and species (Rohmer et al., 19931 and subsequent references). Analysis by reverse phase HPLC ion trap mass spectrometry2 of the BHPs extracted