Electron microscopy may reveal structure of docosahexaenoic acid-rich oil within Schizochytrium sp.
Electron microscopy may reveal structure of docosahexaenoic acid-rich oil within Schizochytrium sp.
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DOI：
10.1007/s11745-000-0655-2
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发表时间：
2000-12-01
期刊：
影响因子：
1.9
通讯作者：
Zeller, S
中科院分区：
文献类型：
--
作者：
Ashford, A;Barclay, WR;Zeller, S
Schizochytrium sp. is an algae-like microorganism utilized for commercial production of docosahexaenoic acid (DHA)-rich oil and dried microalgae for use as a source of DHA in foods, feeds, and nutritional supplements. Electron microscopic analysis of whole cells of Schizochytrium sp. employing sample preparation by high-pressure freeze substitution suggests the presence of secondary and tertiary semicrystalline structures of triacylglycerols within the oil bodies in Schizochytrium sp. A fine secondary structure consisting of alternating light- and dark-staining bands was observed inside the oil bodies. Dark bands were 29 +/- 1 Angstrom in width, and light bands were 22 +/- 1 Angstrom in width. The tertiary (three-dimensional) structure may be a multilayered ribbon-like structure which appears coiled and interlaced within the oil body. In freeze-fracture photomicrographs, Schizochytrium oil bodies exhibited fracture planes with terraces averaging 52 +/- 7 Angstrom in height which could correspond to the combined width of two halves of two light bands and one dark band observed in the high-pressure freeze substitution photomicrographs. The results suggest that triacylglycerols within Schizochytrium sp. oil bodies may be organized in a triple chain-length structure. High-pressure freeze substitution electron micrographs of two other highly unsaturated oil-producing species of microalgae, Thraustochytrium sp. and Isochrysis galbana, also revealed this fine structure, whereas microalgae containing a higher proportion of saturated oil did not. The results suggest that the staining pattern is not an artifact of preparation and that the triple chain-length conformation of triacylglycerols in Schizochytrium sp. oil bodies may be caused by the unique fatty acid composition of the triacylglycerols.
