| 翻訳と辞書 |
| Phospholipid-derived fatty acids ： ウィキペディア英語版 |
Phospholipid-derived fatty acids
Phospholipid-derived fatty acids (PLFA) are widely used in microbial ecology as chemotaxonomic markers of bacteria and other organisms. Phospholipids are the primary lipids composing cellular membranes. Phospholipids can be saponified, which releases the fatty acids contained in their diglyceride tail. Once the phospholipids of an unknown sample are saponified, the composition of the resulting PLFA can be compared to the PLFA of known organisms to determine the identity of the sample organism. PLFA analysis may be combined with other techniques, such as stable isotope probing to determine which microbes are metabolically active in a sample. PLFA analysis was pioneered by D.C. White, MD, PhD,〔Morris, B.E.L., et al., On the contributions of David Cleaveland White, MD, PhD to microbial ecology: celebrating the life of a pioneer. ISME J, 2008. 2: p. 797-804〕 at the University of Tennessee, in the early to mid 1980s.
==Phospholipid fatty acid (PLFA) analysis==
Phospholipid fatty acids (PLFA) are an essential structural component of all microbial cellular membranes. PLFA analysis is a technique widely used for estimation of the total biomass and to observe broad changes in the community composition of the living microbiota of soil and aqueous environments. There has been a surge of interest in PLFAs in recent years, evident from the large increase in peer-reviewed journal references on the subject.〔Frostegard, A., A. Tunlid, and E. Baath, Use and misuse of PLFA measurements in soil. Soil Biol & Biochem, 2011. 43(8): p 1621-25〕 However, there is increasing concern that some researchers are assigning PLFAs to specific microbial classes when in fact those PLFAs are present in a broad range of life forms.〔 Phospholipids can occur in many biological classes (such as in plant roots, fungi, as well as in soil bacteria), so care has to be taken in over-assigning PLFA biomarkers to the wrong class. Even though phospholipids occur in many different life forms, the fatty acid side chains between differing life forms can be quite unique. Polyunsaturated fatty acids (''e.g.'' 18:3 ω3c) are found in plants, algae and cyanobacteria, but are often not present in bacteria. Monounsaturated fatty acids (particularly at the omega-7 position), odd-chain saturated fatty acids (''e.g.'' 15:0), branched-chain fatty acids (mainly iso/anetiso and 10-methyl) and cyclopropane fatty acids (''e.g.'' 19:0 cyclo ω7c) are mostly synthesized by bacteria. The monounsaturated fatty acid, 16:1 ω5c, is mostly synthesized by Arbuscular mycorrhizal fungi (AMF) and the polyunsaturated fatty acid, 18:2 ω6c (Linoleic acid), is mostly synthesized by Ectomycorrhizal fungi.
The basic premise is that as individual organisms (especially bacteria and fungi) die, phospholipids are rapidly degraded and the remaining phospholipid content of the sample is assumed to be from living organisms. As the phospholipids of different groups of bacteria and fungi contain a variety of somewhat unique fatty acids, they can serve as useful biomarkers for such groups. PLFA profiles and composition can be determined by purifying the phospholipids and then cleaving the fatty acids for further analysis. Knowledge of the composition and metabolic activity of the microbiota in soils, water and waste materials is useful in optimizing crop production, in bioremediation and in understanding microbial ecosystems. Soil microbial community analysis by PLFA has been a widely used technique due to the sensitive, reproducible measurement of the dominant portions of the soil microbiota and the fact that PLFA does not require cultivation of the organisms.〔Kaur, A., et al., Phospholipid fatty acid - A bioindicator of environmental monitoring and assessment in soil ecosystem. Current Science, 2005. 89(7): p. 1103-1112〕 Sampling of soil populations by culturing has proven not cost effective and results in biased results due to the differing ease of culturing of some organisms. The main drawback of PLFA has been that the extraction time is very long and cumbersome. A new 96-well plate PLFA extraction procedure has been developed which represents a 4-to-5 fold increase in throughput over traditional PLFA extraction methods. This new method, coupled to new software tools for analyzing the PLFA data, will be useful to laboratories performing large numbers of PLFA analyses, or for laboratories wanting to begin PLFA research.〔Buyer, J.S., and M. Sasser, High throughput fatty acid analysis of soils. App Soil Ecol, 61(2012): p 127-130
| http://dx.doi.org/10.1016/j.apsoil.2012.06.005〕
抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』
■ウィキペディアで「Phospholipid-derived fatty acids」の詳細全文を読む
スポンサード リンク
| 翻訳と辞書 : 翻訳のためのインターネットリソース |
Copyright(C) kotoba.ne.jp 1997-2016. All Rights Reserved.
|
|