Document Type

Dissertation

Publication Date

Spring 4-10-1964

Abstract

The total lipid of the membrane ghost fraction of Streptoccus fecalis (ATCC 9790) was extracted and found to be 20.8 percent of the membrane dry weight. Silicic acid chromatography yielded two main types of lipid, polar lipid (77 per cent) and glyceride (22 per cent). Thin layer chromatography revealed that the polar lipid consisted of two components, slow polar lipid and fast polar lipid. A solvent system was devised which resolved the two polar lipids on a silicic acid column. The fast polar lipid constituted 54 per cent and the slow polar lipid 23 per cent of the total lipid. Amino nitrogen and choline were not detected in the polar lipids, but the slow lipid contained carbohydrate. The infrared spectra of the fast and slow lipids were consistent with that of a phosphatide. Chemical analysis of the fast polar lipid indicated n ester:phosporus ratio of 4.9:2 and 3.75 per cent phosphorous. Paper chromatography of the deacylated lipid before and after hydrolysis suggested that the water-soluble moiety was diglycerophosphorylglycerol (GPGPG). Thus the fast polar lipid appears to be diphosphatidylglyceride. The fatty acids of the fast polar lipid determined by gas-liquid chromatography using polar and non-polar systems had the following structure codes: 14:0, 16:0, 16:1, 17:0 cyclopropane, cis- 18:1, and 19:0 cyclopropane. The presence of the cyclopropane ring and of the cis- configuration of the octadecenoic acid were confirmed by infrared spectrophotometry. The slow polar lipid had an ester:phosphorus ratio of 6.1:1, and the fatty acids were qualitatively identical with those of the fast polar lipid.

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