Phospholipid fatty acid analysis

A. Frostegard and E. Baath. The use of phospholipid fatty-acid analysis to e.stimatc bacterial and fungal biomass in soil, Biol. Eeiiil. Soll.s 22 59 (1996). 

Borga, P Nilsson, M., and Tunlid, A. (1994). Bacterial communities in peat in relation to botanical composition as revealed by phospholipid fatty-acid analysis. Soil Biol. Biochem. 26, 841-848. 

Phospholipid Fatty Acid Analysis. Phospholipid fatty acid analysis was carried out on selected humic and fulvic freeze-dried samples of stream, foam, and foam extract from the Suwannee River by Microbial Insights, Inc., (Knoxville, TN). Briefly,... 

Phospholipid Fatty Acid Analysis of Selected Suwannee River Samples. 

Phospholipid fatty acid analysis (PLFA) is based on the determination of signature lipid biomarkers from the cell membranes and walls of microorganisms. Phospholipids are an essential part of intact cell membranes, and information from the lipid analysis provides quantitative insight into three important attributes of microbial communities viable biomass, community structure, and nutritional status. Phospholipid fatty acid prohles have been used to show the response of the microbial community to phosphorus availability (Keinanen et ah, 2002). Signature lipid biomarker analysis may not detect every species of microorganism in an environmental sample accurately, because many species have similar PLFA patterns. 

Where the fat in a meat or meat product sample is to be characterized in terms of the fatty acid profile, extraction of the fat with chloroform/methanol is required. This solvent mixture, while it may not give complete fat extraction, is used to ensure no chemical change to the lipids and the extraction of phospholipids. Fatty acid analysis of the extracted fat is undertaken by formation of volatile methyl esters of the fatty acids (ISO 5509 2000) and determination by gas chromatography (ISO 5508 1990). 

Fenchel T, King G, Blackburn FI (1998) Bacterial biogeochemistry the ecophysiology of mineral cycling. Academic Press, London, UK Francl LJ (1993) Multivariate analysis of selected edaphic factors and their relationship to Heterodera glycines population density. J Nematol 25 270-276 Frostegard A, Tunlid A, Baath E (1993) Phospholipid fatty acid composition, biomass, and activity of microbial comunities from two soil types experimentally exposed to different heavy metals. Appl Environ Microbiol 59 3605-3617... 

Sundh, I., Nilsson, M., and Borga, P. (1997). Variation in microbial community structure in two boreal peatlands as determined by analysis of phospholipid fatty acid profiles. Appl. Environ. Microbiol. 63,1476-1482. 

Sphingomyelin has a unique composition of fatty acids compared to the other phospholipids (Table 1.12) as the fatty acids are mainly long-chain saturated (i.e., 16 0, 22 0, 23 0 and 24 0). To illustrate the differences in fatty acid composition of sphingomyelin, the fatty acid analysis from another study is also listed. Furthermore, Bitman and Wood (1990) and Nyberg... 

Green C. T. and Scow K. M. (2000) Analysis of phospholipid fatty acids (PLFA) to characterize microbial communities in aquifers. Hydrogeol J. 8(1), 126-141. 

Experiment I. In a time-course experiment, mucosal PGE production and phospholipid fatty acid profile were assessed at d 0,4,8,12, and 16 of dietary treatment in formula-fed and naturally reared piglets (n = 5 piglets per time per dietary treatment). Mucosal cells were scraped from proximal ends of the small intestine and frozen at -80°C for later lipid analysis. Lipids were extracted by a modified Folch procedure (15). Phosphatidylcholine (PC) and phosphatidylethanolamine (PE) were separated by thin-layer chromatography (16), and fatty acids in each phospholipid fraction were analyzed by gas chromatography. For eicosanoid measures, fresh mucosal tissue was incubated in Kreb s Ringer bicarbonate buffer as described previously (17). PGE2 was extracted from the incubation media with ethyl acetate and quantified using a competitive enzyme-linked immunosorbent assay (Cayman Chemical, Ann Arbor, MI). 

Figure 1. Dendogram of cluster analysis results from phospholipid fatty acid profiles of rhizosphere and nonvegetated soils from the contaminated site. Comparisons of qualitative differences between the groups of microorganisms present in the different samples illustrated the primary clustering of nonvegetated soil samples with Lespedeza cuneata rhizosphere soil samples, and Solidago sp. rhizosphere soil with Firms taeda rhizosphere soil and Paspalum notatum rhizosphere soil samples. Secondary clustering occurred between Firms taeda soil samples and Faspalum notatum soil samples.

Fatty acid analysis was carried out by gas-liquid chromatography after transmethylation with 14% BF3 in methanol. Quantitation of neutral lipids was performed by this method, and that of phospholipids by phosphorus measurement (Rouser et al., 1970). Radioactivity was determined in a Packard Tri-Carb spectrometer. 

Sundh, L, Borga E,R, Nilsson, M., Svensson, B.H. 1995. Estimation of cell numbers of methanotrophic bacteria on boreal peatlands based on analysis of specific phospholipid fatty acids. FEMS Microbiology Ecology 18 103-112. 

Quantitative estimates of microbial and community structure by means of analysis of the phospholipid fraction have been performed on. sediments, water (135), and dust (136) as well as. soil (137-141). The method is applicable to the study of mixed populations of varying degrees of complexity and is relatively straightforward to perform. A selection of studies involving the analysis of fatty acid profiles of environmental samples are outlined in Table 6. 

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