Unusual minor nonmethylene‐interrupted di‐, tri‐, and tetraenoic fatty acids in limpet gonads

Abstract

Unusual minor nonmethylene-interrupted (NMI) FA have been identified in the lipids of gonads from the limpets Cellana grata and Collisella dorsuosa by using GC-MS of the combination of their 4,4-dimethyloxazoline derivatives and picolinyl esters. Among 23 NMI unsaturated FA from C18 to C22 and C24 identified in this study, 5,11-nonadecadienoic (5,11-19:2), 7,1 6-heneicosadienoic (7,16-21:2), 9,15-tetracosadienoic (9,15-24:2), 5,9,15-docosatrienoic (5,9,15-22:3), and 5,9,15-tetracosatrienoic (5,9,15-24:3) acids may not have been reported previously from living organisms. The presence of 5,11,14,17-eicosatetraenonoic (5,11,14,17-20:4) and 7,13,16,19-docosatetraenenoic (7,13,16,19-22:4) acids as FA components in marine mollusks may be reported here for the first time. In this study, the male and female gonads of both species showed distinct differences in both their composition and proportions of NMI FA. Most NMI FA identified were mainly present in the female gonads of both species, especially in TAG that contained 21 NMI FA.

Males and females gonad fatty acids of the sea urchins Paracentrotus lividus and Arbacia lixula (Echinodermata)

“…These fatty acids are not found in the algae usually consumed by sea urchins; thus, their presence in the gonads of both sea urchins species suggests that they have been formed endogenously by 5 desaturation of their immediate precursors 20:1n-9 and 20:1n-7, as previously described by Zhukova (1991) in molluscs. The levels of NMID were reported to be higher in the female gonads of two limpet species when compared to the male gonads (Kawashima 2005). In our study, the two identiWed NMID showed also higher proportions in ovaries than in testes although diVerences were only signiWcant in A. lixula and not in P. lividus.…”

Occurrence of Novel Nonmethylene-Interrupted C24Polyenoic Fatty Acids in Female Gonad Lipids of the LimpetCellana grata

“…Marked differences between male and female gonads of the two dominant limpet species, Cellana grata and Collisella dorsuosa, were also characterized by the composition and proportions of unusual NMI fatty acids, and the proportions of 16:0, 20:4n-6 and 20:5n-3 as major fatty acid components. Although the unusual long-chain C 24 unsaturated fatty acids in limpet gonads were found in only small or trace amounts, 3) detailed clarification of their positional isomers was not done in the previous study. This paper describes the occurrence of minor C 24 unsaturated fatty acids, including an unusual diene, triene, tetraene, and pentaene in female gonad lipids of C. grata, which may not have been described previously.…”

“…[1][2][3] But their biological role and function in living organisms are not fully understood. A study of the determination of minor fatty acids might provide valuable information for comparative biochemical research on the effects of environmental factors and/or physiological conditions on fatty acid compositions in organisms.…”

“…A study of the determination of minor fatty acids might provide valuable information for comparative biochemical research on the effects of environmental factors and/or physiological conditions on fatty acid compositions in organisms. In our previous studies, 3,4) 23 different NMI fatty acids were identified as unusual minor fatty acid components in limpet gonads by capillary gas chromatography-mass spectrometry (GC-MS) of their 4,4-dimethyloxazoline (DMOX) and picolinyl ester derivatives. Marked differences between male and female gonads of the two dominant limpet species, Cellana grata and Collisella dorsuosa, were also characterized by the composition and proportions of unusual NMI fatty acids, and the proportions of 16:0, 20:4n-6 and 20:5n-3 as major fatty acid components.…”

“…Derivatives of DMOX and picolinyl ester were prepared as described previously. 2,3) These derivatives were dissolved in n-hexane for analysis by GC-MS.…”