02496naa a2200205 a 450000100080000000500110000800800410001902400350006010000210009524501690011626000090028552018660029465000090216065000180216965000090218765300140219670000160221070000160222677300480224220013622014-12-02       2013    bl uuuu     u00u1 u    #d7 a10.1007/s00248-013-0195-22DOI1 aFERNANDES, M. F.  aComparison of whole-cell fatty acid (MIDI) or phospholipid fatty acid (PLFA) extractants as biomarkers to profile soil microbial communities.h[electronic resource]  c2013  aThe whole-cell lipid extraction to profile micro-bial communities on soils using fatty acid (FA) biomarkers is commonly done with the two extractants associated with the hospholipid fatty acid (PLFA) or Microbial IDentifica-tion Inc. (MIDI) methods. These extractants have very dif-ferent chemistry and lipid separation procedures, but often shown a similar ability to discriminate soils from various management and vegetation systems. However, the mecha-nism and the chemistry of the exact suite of FAs extracted by these two methods are poorly understood. Therefore, the objective was to qualitatively and quantitatively compare the MIDI and PLFA microbial profiling methods for detect-ing microbial community shifts due to soil type or manage-ment. Twenty-nine soil samples were collected from a wide range of soil types across Oregon and extracted FAs by each method were analyzed by gas chromatography (GC) and GC-mass spectrometry. Unlike PLFA profiles, which were highly related to microbial FAs, the overall MIDI-FA pro-files were highly related to the plant-derived FAs. Plant-associated compounds were quantitatively related to partic-ulate organic matter (POM) and qualitatively related to the standing vegetation at sampling. These FAs were negatively correlated to respiration rate normalized to POM (Resp POM), which increased in systems under more intensive manage-ment. A strong negative correlation was found between MIDI-FA to PLFA ratios and total organic carbon (TOC). When the reagents used in MIDI procedure were tested for the limited recovery of MIDI-FAs from soil with high or-ganic matter, the recovery of MIDI-FA microbial signatures sharply decreased with increasing ratios of soil to extractant. Hence, the MIDI method should be used with great caution for interpreting changes in FA profiles due to shifts in microbial communities.  asoil  aMicrobiologia  aSolo  aLipídios1 aSAXSENA, J.1 aDICK, R. P.  tMicrobial Ecologygv. 66, p. 145-157, 2013.