Distribution of fatty acids during germination of cottonseeds

Gas chromatographic determination of the fatty acids in the seeds of cottonseed (Gossypium sp.) showed linoleic, palmitic, oleic, and stearic acids, with linoleic acid being the major component. Changes in the composition of fatty acids during various stages of germination were measured in the cotyledons and in the roots. A decrease in the content of all the fatty acids and an 8-fold increase in the moisture content of the cotyledons were observed during the 10 days of germination. There were no significant changes in the fatty acid contents of the roots with the exception of those in linoleic acid which increased by 50% during 4–10 days of germination. The possible significance of these changes is discussed.     

Raman Study on Lipid Droplets in Hepatic Cells Co-Cultured with Fatty Acids

The purpose of the present study was to investigate molecular compositions of lipid droplets changing in live hepatic cells stimulated with major fatty acids in the human body, i.e., palmitic, stearic, oleic, and linoleic acids. HepG2 cells were used as the model hepatic cells. Morphological changes of lipid droplets were observed by optical microscopy and transmission electron microscopy (TEM) during co-cultivation with fatty acids up to 5 days. The compositional changes in the fatty chains included in the lipid droplets were analyzed via Raman spectroscopy and chemometrics. The growth curves of the cells indicated that palmitic, stearic, and linoleic acids induced cell death in HepG2 cells, but oleic acid did not. Microscopic observations suggested that the rates of fat accumulation were high for oleic and linoleic acids, but low for palmitic and stearic acids. Raman analysis indicated that linoleic fatty chains taken into the cells are modified into oleic fatty chains. These results suggest that the signaling pathway of cell death is independent of fat stimulations. Moreover, these results suggest that hepatic cells have a high affinity for linoleic acid, but linoleic acid induces cell death in these cells. This may be one of the causes of inflammation in nonalcoholic fatty liver disease (NAFLD).     

Changes in structure of triglycerides from maturing kernels of corn

Kernels of corn inbred H51 were collected at five intervals after hand pollination. The triglyceride content of the total lipids increased from 8.6% at 10 days after pollination to 78.3% at 60 days. The most active period of triglyceride synthesis occurred from 20 to 45 days after pollination, when the weight of triglycerides per kernel increased from 1.1 to 7.5 mg. Over all the collection periods the percentages of palmitic, linoleic and linolenic acids decreased while oleic acid increased, but from 30 to 60 days after pollination the fatty acid composition of the triglycerides was nearly constant. Stereospecific analysis revealed a general fatty acid pattern for the triglycerides, in which the concentration of the saturated acids was highest in position 1, linoleic acid in 2 and oleic acid in 3. From 20 to 60 days after pollination there was little change in the fatty acid composition at the 1 position, but the largest changes occurred at the 3 position where palmitic and oleic acids decreased 5.1% and 7.3%, respectively, and linoleic acid increased 13.4%. The variations in the molecular species of the triglycerides were determined by silver nitrate thin layer chromatography and were found to be small from 20 to 60 days after pollination, except for an increase in trilinolein from 5.2 to 11.9%. Stereospecific analyses of four major triglycerides species, SMD, M₂D, SD₂, and MD₂, revealed larger changes in fatty acid distribution at individual positions during maturation than were apparent from analyses of the total triglycerides. Presented in part at the AOCS Meeting, Ottawa, September 1972.     

The effect of germination upon the fat of the soybean

Soybeans of the Chippewa variety of two crops, 1956 and 1957, were germinated in the dark at 25C and the levels of total dry matter and crude fat of both the seedling axis and cotyledons were determined at various periods up to 12 days. The fatty acid content, neutral fat content of the crude fats of the cotyledons, and the fatty acid composition of neutral fat were determined. The fatty acid composition was measured by the ultraviolet spectrophotometric method. There was a continuous decrease in the total dry matter and crude fat of the cotyledons and whole seedlings of soybeans during 12 days of germination, contrary to observations of some of the earlier workers. Although there was a preferential utilization of the non-fat dry matter during the first two days of germination, there was a slight but significant loss of fat, which gradually increased with the germination time. Surprisingly little change in the fatty acid composition of the reserve triglycerides occurred even during their most rapid loss from the cotyledons. However, observed changes were statistically significant. No loss of oleic acid occurred until after the second day of germination and its more rapid loss; compared to the other fatty acids, occurred during the period of most rapid fat loss. The significance of this observation and its relationship to oleic acid as the key intermediary in fat metabolism in plants is discussed. Part of the Ph.D. thesis submitted by B. E. Brown in June 1959.     

Fatty acids in lipids of maturing wheat

Two varieties of hard red winter wheat were sampled at various stages of maturity. The lipids in those samples were fractionated into free polar, free nonpolar and bound lipids. Fatty acids of those fractions were determined. Major acids present were palmitic, oleic, linoleic and linolenic. Both wheat samples showed similar qualitative, but not quantitative patterns in distribution of fatty acids during maturation. In the free polar lipid fraction, the palmitic acid content decreased with maturation while the linoleic acid content increased. The free nonpolar fractions showed a slight increase in linoleic acid; the concentration of other acids decreased slightly as the wheat matured. The bound lipid fraction showed a marked increase in linoleic acid, accompanied by decreases in the other major fatty acids, especially linolenic. Cooperative investigations of Kansas Agricultural Experiment Station and Crops Research Div., ARS, USDA.     

Developmental changes in fatty acid composition of oil in kernel fractions of corn (Zea mays L.)

Gas liquid chromatography was used to determine the change in fatty acid composition of oil from three kernel fractions (pericarp, endosperm and germ) during kernel maturation of four inbred lines of corn. Inbred lines were sibpollinated, and sampling of ears began six days after pollination (DAP) and continued at three day intervals until 33 DAP and then at weekly intervals until 54 DAP. Proportion of palmitic acid in the pericarp oil rapidly decreased between 6 and 12 DAP while oleic and linoleic acids increased during the same period. Changes in fatty acid composition of oil from the endosperm during kernel maturation were erratic and no consistent trends were evident. In the germ oil, palmitic and linolenic acid proportions decreased during kernel maturation, while oleic acid decreased and linoleic acid increased during kernel maturation for three of the four inbred lines. By about 24 to 27 DAP, the fatty acid composition of oil in the mature kernel was established. Since kernel fractions are of different genetic origin, a study of developmental changes in lipid classes or in fatty acid composition of oil should be limited within kernel fractions that have a similar genetic constitution. Approved as Journal Series Paper No. 723, University of Georgia, College of Agriculture Experiment Stations.     

Tissue culture of cocoa bean (Theobroma cacao L.): changes in lipids during maturation of beans and growth of cells and calli in culture

Callus cultures ofTheobroma cacao L., initiated from explants of immature cocoa bean cotyledons, contained 5.3%–6.4% lipids (dry wt basis). The major fatty acids were palmitic, oleic and linoleic acids. Cell suspensions contained 5.7–7.7% total lipids which had a higher polyunsaturated fatty acid content than total lipids of the calli. Phospholipids and glycolipids were the predominant lipid classes of calli and cell suspensions. Immature cocoa beans at early stages of development contained much higher polyunsaturated fatty acids, higher polar lipids and lower triglycerides than did mature ripe beans. Ripe cocoa beans contained 54% total lipids of which 96.8% where triglycerides. The fatty acid composition of total lipids of calli and cell suspensions were similar to those of the immature cocoa beans.     

Triacylglycerol structure of human colostrum and mature milk

Because triacylglycerol (TAG) structure influences the metabolic fate of its component fatty acids, we have examined human colostrum and mature milk TAG with particular attention to the location of the very long chain polyunsaturated fatty acid on the glycerol backbone. The analysis was based on the formation of various diacylglycerol species from human milk TAG upon chemical (Grignard degradation) or enzymatic degradation. The structure of the TAG was subsequently deduced from data obtained by gas chromatographic analysis of the fatty acid methyl esters in the diacylglycerol subfractions. The highly specific TAG structure observed was identical in mature milk and colostrum. The three major fatty acids (oleic, palmitic and linoleic acids) each showed a specific preference for a particular position within milk TAG: oleic acid for thesn-1 position, palmitic acid for thesn-2 position and linoleic acid for thesn-3 position. Linoleic and α-linolenic acids exhibited the same pattern of distribution and they were both found primarily in thesn-3 (50%) andsn-1 (30%) positions. Their longer chain analogs, arachidonic and docosahexaenoic acids, were located in thesn-2 andsn-3 positions. These results show that polyunsaturated fatty acids are distributed within the TAG molecule of human milk in a highly specific fashion, and that in the first month of lactation the maturation of the mammary gland does not affect the milk TAG structure.     

Changes in lipid class and fatty acid compositions during maturation ofHibiscus esculentus andHibiscus cannabinus seeds

The major lipid classes and their constituent fatty acids were analyzed in maturing seeds ofHibiscus esculentus andH. cannabinus. The seeds matured in 40 and 45 days, respectively. The active accumulation period was from the 13th to 25th and 15th to 30th day after flowering, respectively. While a continuous increase in the content of triacylglycerols (TAG) was noticed inH. esculentus, TAG was at its peak inH. cannabinus on the 20th day after flowering. The contents of polar lipids were high in the immature seeds but decreased during maturation. The major fatty acids in both species were palmitic, oleic and linoleic. Cyclopropane fatty acids were present only in TAG of both species throughout maturation period. Cyclopropene and epoxy acids appeared in TAG in traces at the final stages of seed maturation. Oleic and linoleic acids were preferentially esterified at the secondary positions of TAG. The contents of palmitic and stearic acids at the secondary positions were sharply reduced as TAG accumulated.     

Changes in the structure of soybean triglycerides during maturation

Soybeans of the Hawkeye variety were picked at eleven periods from 30 to 111 days after flowering and extracted with chloroform-methanol. The triglyceride fraction of five pickings, selected 35 to 91 days after flowering (when synthesis of lipid was most active), were isolated by silicic acid thin layer chromatography (TLC) and species composition determined using argentation TLC and lipase hydrolysis. The triglyceride content of the total lipid increased from 6.5% at 30 days after flowering to 85% in the mature bean (111 days). The major changes in fatty acid composition of the triglycerides occurred during the first 52 days after flowering. During this period linolenic acid decreased from 34.2% to 11.7%, the percentages of linoleic and oleic acids increased, stearic remained fairly constant and palmitic decreased slightly. Large quantitative changes occurred in the molecular species of the triglycerides of the bean during maturation; some triglycerides containing linolenic acid could not be detected approximately 66 days after flowering. Although changes occurred in the percentage and amount of each triglyceride species, the positional distribution of fatty acids remained virtually unchanged throughout maturation. Linolenic acid was distributed fairly uniformly between the β-position and the α-positions, linoleate favored esterification in the β-position, and oleate the α-positions. Most of the stearic and palmitic acids were esterified in the α-positions. The consistency of the positional arrangement of the fatty acids indicated that the mode of glyceride synthesis was established very early during maturation and molecular species composition was controlled by the fatty acids available for synthesis.     

Fatty acid composition of oil from soybean leaves grown at extreme temperatures

Leaves from soybean (Glycine max (L.) Merr.) plants were assayed to determine if the relationship between temperature and relative fatty acid composition observed in the seed oil also existed for the triglycerides in the leaf oil. Leaf samples were harvested from eight soybean lines (A5, A6, C1640, Century, Maple Arrow, N78-2245, PI 123440 and PI 361088B) grown at 40/30,28/22 and 15/ 12°C day/night. At 40/30 and 28/22°C, seven fatty acids were observed at a level greater than 1.0%. These included the five major fatty acids found in the seed oil: palmitic (16:0), stearic (18:0), oleic (18:1), linoleic (18:2) and linolenic (18:3) acid; plus two fatty acids that had retention times the same as palmitoleic (16:1) and γ-linolenic (18:3 g) acid. In addition, an eighth fatty acid that had a retention time the same as behenic (22:0) acid was found in the leaves of all lines at 15/12°C. Palmitic, palmitoleic and stearic acid content did not differ significantly over temperatures. The oleic and linoleic acid content were each highest at 15/12°C, while the γ-linolenic and the linolenic acid content were each highest at 40/30°C. The fatty acid composition of the triglyceride portion of the leaf oil did not display the same pattern over temperatures as that observed for seed oil.     

Definite influence of location and climatic conditions on the fatty acid composition of sunflower seed oil

Percentages of linoleic, oleic and stearic acids present significant differences between growing areas, whereas palmitic acid content remains practically constant, or at least presents no significant relation to the growing area. Nevertheless, palmitic acid appears to follow a pattern that relates its content to the total content of the other three major fatty acids. Seeds grown in the northern part of Spain presented a higher linoleic content than seeds grown in the South, which is in agreement with the general theory found in prior studies. Although there is an inverse correlation between oleic and linoleic content, we have found that the total content of both is neither constant nor independent of temperature, and increases when temperature and oleic acid increase. However, stearic content increases when the combination of linoleic and oleic acid decreases, suggesting a total constant value for the combination of these three acids. The average temperature of the are during development of the seed and the local climatic conditions have the greatest influence over fatty acid composition, while the seed variety presents limited influence.     

Oviposition response ofLobesia botrana females to long-chain free fatty acids and esters from its eggs

Avoidance of occupied ovisposition sites supposes that females perceive information related to their own progency. Fatty acids identified from egg extracts have been reevaluated using a different extraction method, and we have investigated the dose-dependent oviposition response of European grape vine moths (Lobesia botrana) to myristic acid, palmitic acid, palmitoleic acid, stearic acid, oleic acid, linoleic acid, methyl palmitate, methyl oleate, and ethyl palmitate; all except ethyl palmitate have been identified from eggs ofL. botrana. A methylene dichloride extract of eggs fromL. botrana revealed the presence of saturated free fatty acids (myristic, palmitic, and stearic) and unsaturated acids (palmitoleic, oleic, linoleic, and linolenic) in amounts ranging from 3.9 ng/egg equivalent for myristic acid to 30 ng/egg equivalent for palmitic and oleic acids. The extract also contained traces of methyl palmitate and methyl stearate. The greatest avoidance indexes were observed in response to palmitic, palmitoleic, and oleic acids. All the other compounds tested caused weaker responses. A reduction in the number of eggs laid was observed when moths were exposed to each of the esters applied at 0.3 µg per application spot. Reduction in eggs laid was also observed at a 10-fold higher dose of oleic acid. The present results confirm that general and simple molecules can be involved in the regulation of oviposition site selection and that they may participate in chemical marking of the eggs.     

Fatty acid biosynthesis during embryogenesis in the amphibianBufo arenarum Hensel

The fatty acid composition and biosynthesis of fatty acids were studied during early embryogenesis of the toadBufo arenarum Hensel. The ova and stages up to the 6 1/2 day embryo have similar fatty acid compositions, with ca. 70% unsaturated acids. The eggs and embryo were permeable to acetate and impermeable to palmitic, linoleic, and eicosa-8,11,14-trienoic acid. Labeled acetate was incorporated by the eggs into the saturated acids-lauric, myristic, palmitic, stearic, arachidic, and behenic-and into the unsaturated acids-myristoleic, palmitoleic, oleic, and eicosaenoic acids. During segmentation and gastrulation, de novo biosynthesis of fatty acids increased, desaturation to myristoleic, palmitoleic, and oleic acids was enhanced; and fatty acids were esterified to triglycerides, phosphatidyl choline, and phosphatidyl ethanolamine. The feeding embryo (11 days) changed the pattern of incorporation to less incorporation into triglycerides.     

Association of seed size with genotypic variation in the chemical constituents of soybeans

Ten soybean genotypes grown in 1992 with seed size ranging from 7.6 to 30.3 g/100 seeds and maturity group V or VI were selected and tested for oil and protein content and for fatty acid composition. In these germplasm, protein varied from 39.5 to 50.2%, oil, 16.3 to 21.6%, and protein plus oil, 59.7 to 67.5%. Percentages of individual fatty acids relative to total fatty acids varied as follows: palmitic, 11.0 to 12.8; stearic, 3.2 to 4.7; oleic, 17.6 to 24.2; linoleic, 51.1 to 56.3 and linolenic, 6.9 to 10.0. Seed size showed no significant correlations with individual saturated fatty acids, protein or oil content. However, significant correlations were found between seed size and individual unsaturated fatty acids: positive with oleic, and negative with linoleic and linolenic. Oil and protein content were negatively correlated with each other. Among the major fatty acids, only the unsaturated were significantly correlated with each other: negative between oleic and linoleic or linolenic, and positive between linoleic and linolenic. A subsequent study with soybeans grown in 1993 generally confirmed these findings. Variation in relative percentages of unsaturated fatty acids andr values for most pairs of relationships were even higher than those obtained from the 1992 crop. Presented at the 85th AOCS Annual Meeting and Expo, Atlanta, Georgia, May 8–12, 1994.     

Composition and biosynthesis of fatty acids inPyramimonas grossii

The green algaPyramimonas grossii orginating in the coastal waters of the Atlantic Ocean Argentina was subcultured until a monoalgal culture was obtained. The fatty acid composition of the alga grown in a mineral medium at 12 C was determined by gas liquid chromatography (GLC) on 2 columns. The major fatty acids were oleic, linoleic, palmitic and α-linolenic acids, but the 20-carbon polyunsaturated acids, 20∶4ω6 and 20∶5ω3, respectively, belonging to the linoleic and α-linolenic series, were also found. Incubation with [¹⁴C] oleate, [¹⁴C] acetate, [¹⁴C] linoleate and [¹⁴C] α-linolenate suggests that linoleate is not directly converted to α-linolenate. [¹⁴C] Acetate was easily converted to palmitic, palmitoleic and oleic acids. However, after 48 hr of incubation, only traces of radioactivity were detected in linoleic acid and no label was found in α-linolenic acid.     

Variation in Fatty Acid Compositions, Oil Content and Oil Yield in a Germplasm Collection of Sesame (Sesamum indicum L.)

The variation in oil content, oil yield and fatty acid compositions of 103 sesame landraces was investigated. The landraces varied widely in their oil quantity and quality. The oil content varied between 41.3 and 62.7%, the average being 53.3%. The percentage content of linoleic, oleic, palmitic and stearic acids in the seed oil ranged between 40.7–49.3, 29.3–41.4, 8.0–10.3 and 2.1–4.8%, respectively. Linolenic and arachidic acids were the minor constituents of the sesame oil. Linoleic and oleic acids were the major fatty acids of sesame with average values of 45.7 and 37.2%, respectively. The total means of oleic and linoleic acids as unsaturated fatty acids of sesame were about 83% which increases the suitability of the sesame oil for human consumption. The superiority of the collection was observed in oil content. The oil content of a few accessions was above 60%, proving claims that some varieties of sesame can reach up to 63% in oil content. The accessions with the highest oil content were relatively richer in the linoleic acid content while there were some landraces in which linoleic and oleic acid contents were in a proportion of almost 1:1. The results obtained in this study provide useful background information for developing new cultivars with a high oil content and different fatty acid compositions. Several accessions could be used as parental lines in breeding programmes aiming to increase sesame oil quantity and quality.     

Fatty acid composition of oleaster pulp and pit oils

Fatty acid compositions of oleaster pulp and pit oils were determined by gas chromatography in 4 samples of different varieties. Pit oils were highly unsaturated, containing >90% linoleic, oleic, and linolenic acids, as well as traces of palmitoleic acid. Saturated fatty acids consisted of palmitic and stearic acids with traces of arachidic acid. Pulp oils showed fatty acid compositions entirely different from that of pit oils. They contained 9 saturated fatty acids, C₁₂ to C₂₄, some of them with high quantities, up to 34.9%, of the total fatty acids. Unsaturated fatty acids, mainly oleic and linoleic, with low quantities of palmitoleic and linolenic acids composed about one-third of the total fatty acids.     

Influence of Temperature on the Fatty Acid Composition of the Oil From Sunflower Genotypes Grown in Tropical Regions

The influence of temperature on the fatty acid composition of the oils from conventional and high oleic sunflower genotypes grown in tropical regions was evaluated under various environmental conditions in Brazil (from 0° S to 23° S). The amounts of the oleic, linoleic, palmitic and stearic fatty acids from the sunflower oil were determined using gas chromatography (GC). The environment exhibited little influence on the amounts of oleic and linoleic fatty acids in high oleic genotypes of sunflower. In conventional genotypes, there was broad variation in the average amounts of these two fatty acids, mainly as a function of the minimum temperature. Depending on the temperature, especially during the maturation of the seeds, the amount of oleic acid in the oil of conventional sunflower genotypes could exceed 70 %. Higher temperatures led to average increases of up to 35 % for this fatty acid. Although the minimum temperature had the strongest effect on the fatty acid composition, locations at the same latitude with different minimum temperatures displayed similar values for both oleic acid and linoleic acid. Furthermore, minimum temperature had little influence on the amounts of palmitic and stearic fatty acids in the oil.     

In vivo and in vitro lipid accumulation inBorago officinalis L.

Seeds of 13 accessions of borage (Borago officinalis) varied in total fatty acid content from 28.6 to 35.1% seed weight, with linoleic, γ-linolenic, oleic and palmitic as the predominant fatty acids, averaging 38.1%, 22.8%, 16.3% and 11.3% of total fatty acids, respectively. There was an inverse relation between γ-linolenic acid (25.0 to 17.6%) and oleic acid (14.5 to 21.3%). Fatty acid content of leaf tissues was 9.1% dry weight, with α-linolenic acid 55.2% and γ-linolenic acid 4.4% of total fatty acids. Cotyledons were the major source of fatty acids in seeds. Seed fatty acid content increased from <1 mg at six days postanthesis to about seven mg at maturity (22 to 24 days). Individual fatty acid content of seed was relatively constant after day 8. When immature embryos from 6 to 16 days postanthesis were cultured in a liquid or semisolid basal medium, fatty acid composition was similar to that of in vivo-grown seeds. Growth of cultured embryos decreased as sucrose concentration was increased from 3 to 20% in the basal medium, and most embryos did not survive 30% sucrose; fatty acid as a percentage of dry weight was maximal at 6% sucrose.