Detection of microbial groups metabolizing a substrate in soil based on the [C-14]quinone profile

Analysis of [C-14] respiratory quinones synthesized in soil for 6 h after s piking with [U-C-14]glucose, [U-C-14]glycine, and [1,2-C-14]acetate enabled to fingerprint the microorganisms metabolizing each substrate in soil and to determine the Whole structure of the microbial communities at the same t ime. The [C-14]quinones synthesized from [U-C-14]glucose were the same as t hose from [(UC)-C-14]glycine in soil, suggesting that the same microbial gr oups metabolized glucose and glycine under the given conditions. No [C-14]q uinones from [1,2-C-14] acetate were detected in soil, indicating that the metabolism of acetate by microorganisms is negligible. The profiles of [C-1 4]quinones from [U-C-14]glucose were compared between Nagoya University Far m soils subjected to 4 different fertilizing practices. The soils receiving farmyard manure contained [C-14]menaquinones with highly hydrated isopreno id units, which indicated the presence of Actinobacteria metabolizing gluco se. The soil receiving only chemical fertilizers contained [C-14]ubiquinone with 8 isoprenoid units (Q-8), indicating the presence of beta and gamma s ubdivisions of Proteobacteria. All the 4 soils were characterized by the hi gh proportions of [C-14] MK-6 and a mixture of [C-14] MK-8(H-4) and [C-14]M K-9. The Q-9 and Q-10(H-2), indicators of fungi, were not labeled under mos t of the conditions.