Detection of microbial groups metabolizing a substrate in soil based on the [l4C] quinone profile

Abstract

Analysis of [l4C]respiratory Quinones synthesized in soil for 6 h after spiking with [U-14C]glucose, [U-l4C]glycine, and [1,2-l4C]acetate enabled to fingerprint the microorganisms metabolizing each substrate in soil and to determine the whole structure of the microbial communities at the same time. The [l4C]- Quinones synthesized from [U-l4C] glucose were the same as those from [U-l4C] gIycinc in soil, suggesting that the same microbial groups metabolized glucose and glycine under the given conditions. No [l4C]quinones from [1,2-14C] acetate were detected in soil, indicating that the metabolism of acetate by microorganisms is negligible. The profiles of [l4C]quinones from [U-l4C]- glucose were compared between Nagoya University Farm soils subjected to 4 different fertilizing practices. The soils receiving farmyard manure contained [l4C]menaquinones with highly hydrated isoprenoid units, which indicated the presence of Actinobacteria metabolizing glucose. The soil receiving only chemical fertilizers contained [14C]ubiquinone with 8 isoprenoid units (Q-8), indicating the presence of beta and gamma subdivisions of Proteobacteria. All the 4 soils were characterized by the high proportions of [14C] MK-6 and a mixture of [l4C]MK-8(H4) and [l4C]MK-9. The Q-9 and Q-10(H2) indicators of fungi, were not labeled under most of the conditions. © 1999, Taylor & Francis Group, LLC.