title: A gas chromatographic/mass spectrometric method for tracing the microbial conversion of glucose into amino sugars in soil.
abstract: Amino sugars in soils are heterogeneous and have been used as microbial residue biomarkers to investigate the microbial contribution to soil organic matter. However, it is not clear what the available carbon source is and how glucose is utilized for the synthesis of soil amino sugars. This paper presents a new gas chromatography/mass spectrometry (GC/MS) approach for the identification of 13C incorporation into three amino sugars, D-glucosamine, D-galactosamine, and muramic acid, in soil incubated with U-13C-glucose. Method evaluation showed that the chemical ionization (CI) mode was suitable for all these amino sugars, but that electron impact (EI) mode was applicable only to glucosamine and galactosamine. The 13C conversion rate was estimated based on the abundance ratio of the ions corresponding to the masses of the ions F+n and F (where n is the skeleton carbon number in the fragment ions F of the amino sugars) and calculated as atom percentage excess. The reproducibility of the method was excellent and clearly adequate for the present purpose. In addition, the new approach is highly accurate as tested with mixtures of U-13C-glucose and natural glucose.
authors.affiliation: Key Laboratory of Terrestrial Ecological Process, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110016, China.
authors.forename: Hongbo
authors.initials: H
authors.lastname: He
authors.forename: Hongtu
authors.initials: H
authors.lastname: Xie
authors.forename: Xudong
authors.initials: X
authors.lastname: Zhang
authors.forename: Yanhong
authors.initials: Y
authors.lastname: Wang
authors.forename: Yeye
authors.initials: Y
authors.lastname: Wu
mesh_terms: D000606:Amino Sugars / Q000032:analysis* / Q000378:metabolism; D001419:Bacteria / Q000378:metabolism; D002247:Carbon Isotopes / Q000032:analysis; D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods* / Q000592:standards; D005947:Glucose / Q000032:analysis* / Q000493:pharmacokinetics; D015203:Reproducibility of Results; D012987:Soil / Q000032:analysis*; D012988:Soil Microbiology
chemical_list: D000606:Amino Sugars; D002247:Carbon Isotopes; D012987:Soil; D005947:Glucose