SULFONOLIPIDS AS A BIOMARKER TO MONITOR THE POPULATION-DYNAMICS OF THE GENERA CYTOPHAGA AND FLEXIBACTER IN SOIL WORKED BY THE EARTHWORM APORRECTODEA-TURGIDA

Gliding bacteria of the genera Cytophaga and Flexibacter contain unusual sulfonolipids, capnoids, that may serve as a biochemical marker for these organisms in soil. We examimed recovery of sulfonolipids from cells added to soil and the dynamics of S-35-labeled sulfonolipids in Boil with or without added Aporrectodea turgida. Recovery of sulfonolipids from intact cells added to soil was complete, and sulfonolipids did not persist in soil in an extractable form upon cell death. Application of the biomarker technique to soil influenced by the activities of the endogeic earthworm A. turgida demonstrated three phases of S-35-labeled sulfonolipid dynamics-accumulation, steady state and loss-and is consistent with the expected pattern for a biomarker sensitive to changes in the biomass of Cytophaga and Flexibacter spp. in soil. The physical rearrangement of the soil fabric by the activities of earthworms did not increase the size or alter the gross composition of the microbial biomass, as indicated by phospholipid-P and analysis of profiles of fatty acids released from phospholipids. Instead, there was a stimulation of subsets of the biomass, as illustrated by the altered dynamics of S-35-labeled sulfonolipids.