Increase In Total Fatty Acids Research Articles

Intestinal absorption of radioactive long-chain saturated fatty acids by the larval dragon-fly Aeshna cyanea and co-absorptive effects of other stable fatty acids

In contrast with unsaturated fatty acids, ingestions of long-chain saturated fatty acids by Aeshna cyanea larvae failed to induce an accumulation of lipid droplets in the intestinal absorptive cells, so that it remained questionable whether they were absorbed or not (Bauerfeind and Komnick, 1989). Therefore, we reinvestigated the question with the use of radioactive tracers, which were orally infused under two conditions: at low doses and at high doses prepared by the addition of other stable fatty acids. We found that carboxyl- 14C labelled long-chain stearic and palmitic acids, as well as the medium-chain lauric acid studied for comparison, were indeed absorbed from low doses of 7 nmol. They were incorporated predominantly into the phospholipids of the midgut wall and released into the haemolymph mainly as diacylglycerols. A substantial part was also transported as cholesterylester. The increase in total fatty acids of the infusates by the addition of 1.8 μmol stable oleic, arachidonic, myristoleic acids and lauric acid ethylester, which at high doses induce the formation of triacylglycerol droplets within the midgut enterocytes, markedly reduced the absorption rates of the radioactive saturated fatty acids and greatly favoured their incorporation into di- and triacylglycerols on the expense of the phospholipids and, at a minor part, on the expense of cholesterylester. By contrast, the addition of 1.8 μmol stable caproic acid yielded little, if any, effect on the absorption pattern of the radioactive palmitic acid. The results suggest that the co-absorption of medium- and long-chain saturated and unsaturated fatty acids is interdependent utilizing the same or similar uptake mechanisms and dose-dependent esterification pathways, while it is largely independent of and probably different from the absorption of short-chain fatty acids.

Microalgae for use in tropical aquaculture II: Effect of salinity on growth, gross chemical composition and fatty acid composition of three species of marine microalgae

The influence of salinity on the growth, gross chemical composition and fatty acid composition of three species of marine microalgae,Isochrysis sp.,Nannochloropsis oculata andNitzschia (frustulum), was investigated. There was no significant change in growth rate ofIsochrysis sp. andN. (frustulum) over the experimental range of salinity (10–35 ppt), whileN. oculata had a significantly slower growth rate only at 35 ppt. The ash content of all three species increased with increasing salinity. Two species,Isochrysis sp. andN. oculata, showed significant linear increases in total lipid content with increasing salinity over the range 10 to 35 ppt.N. (frustulum) showed significant linear decrease in total lipids, with the highest percentage at low salinity within the range 10–15 ppt. Variation in salinity had only a slight effect on the total protein, the soluble carbohydrate and chlorophylla content of all species. All species responded to change in salinity by modifying their cellular fatty acid compositions. Significant positive correlations were observed between increase in salinity and increase in the percentage ofcis-9-hexadecenoic acid [16:1 (n-7)] over the entire experimental range inN. (frustulum) and between 25–35 ppt inN. oculata. There were curved relationships between salinity and percentage of hexadecanoic acid [16:0] inN. oculata andN. (frustulum), with maxima within the range 25–30 ppt for both species. A curved relationship was found between salinity and percentage of eicosapentaenoic acid [20–5(n-3)], forN. (frustulum), with lowest percentages of the fatty acid within the range 25–30 ppt. There was no consistent pattern in the percentages of other major fatty acids as functions of salinity. The Northern Territory isolateN. (frustulum) was unusual in having a substantial increase in total fatty acids with decreasing salinity (85 mg g−1 dry wt at 10 ppt compared with 33 mg g−1 at 35 ppt). The optimum salinities for the production of maximum amount of lipids and the essential fatty acids 20:5(n-3) and/or 22:6(n-3) were as follows:

2‐Deoxy‐d‐glucose uptake and fatty acid content in fibroblast cultures from children with syndromic paucity of interlobular bile ducts (alagille syndrome)

2-Deoxy-D-glucose (2-DOG) uptake was studied in skin fibroblast cultures from control children and children with Alagille syndrome or syndromic paucity of interlobular bile ducts (PILBD). No significant differences in uptake were observed between patients and controls. However, as the scatter of the results was larger in the fibroblasts from patients, we attempted to establish for these patients a relationship between 2-DOG uptake and some biochemical parameters. We observed an inverse relationship between this uptake and the levels of plasma cholesterol and phospholipids (r = -0.85). Compared to controls, 2-DOG uptake was significantly lower in cultures from patients who had very high levels of cholesterol (P2 group), but not in cultures from patients with moderately increased levels of cholesterol (P1 group). The level of total cellular cholesterol in cultured cells from the P1 and P2 groups was not significantly different from the control level, but we found marked differences between the concentrations of fatty acids. In the cultures from patients (especially the P2 group), we observed a significant increase in total fatty acids; among the saturated fatty acids, this increase chiefly concerned the 18:0 (14%) and among the polyunsaturated the n - 3 fatty acids (55%). The high concentrations of 20:5, 22:5 and 22:6, which enhance membrane fluidity, might explain the decrease in 2-DOG uptake found in the cultures from patients (P2 group) with PILBD. The nature of these abnormalities might be connected with the genetic origin of Alagille syndrome.

Direct transesterification of all classes of lipids in a one-step reaction.

Conventional techniques for the determination of fatty acid composition of lipids require solvent extraction, purification, hydrolysis, and derivatization procedures that are both lengthy and cumbersome. A 1-hr direct transesterification procedure carried out in methanol-benzene 4:1 with acetyl chloride circumvented all these steps and was applicable for analysis of both simple (triglycerides) and complex lipids (cholesteryl esters, phospholipids, and sphingomyelin). Recoveries (greater than 95%) of standards unaffected by the presence of 5% water and 200 mg of silica suggested that the technique could be used for the quantitative analysis of total fatty acids as well as of fatty acids in classes of lipids separated on silica from biological samples. When compared to the Folch procedure, the technique led to a 20.1% increase in total fatty acids for plasma, 3.9% for feces, 7.4% for bile, and 9.7% for rat liver. We therefore conclude that this one-step direct transesterification procedure is superior to currently used methods, not only because of its simplicity and speed, but also because of its added precision.

Factors Affecting in Vitro Fatty Acid Content and Composition in Asexual Embryos of Theobroma cacao

Abstract Asexual embryos of cacao (Theobroma cacao L.) were grown for 45 days in a modified Murashige and Skoog (MS) liquid medium with sucrose concentration increased stepwise from 3% to 27% and supplemented with various concentrations of MS salts, inorganic and organic nitrogen (casein hydrolysate), phosphorus, potassium, coconut water, 6-benzylamino purine (BA), naphthaleneacetic acid (NAA), gibberellic acid (GA), and abscisic acid (ABA). Embryo growth decreased but fatty acid accumulation per gram dry weight was unaffected when total salt concentrations were less than full-strength MS levels. Growth and fatty acid accumulation was inhibited as total salt concentrations were increased from 1 × to 8 × full-strength MS levels. Eliminating inorganic nitrogen, organic nitrogen, potassium, and phosphorus from the medium tended to reduce embryo growth and fatty acid accumulation. None of the growth-regulating substances used increased fatty acid accumulation, but high concentrations of BA (10 and 100 ppm) or NAA (100 ppm) were inhibitory; there was little response to GA or ABA. An increase in total fatty acids in all experiments was associated with increased mole percentage of oleic and stearic acids and decreased linoleic and linolenic acids.

The time-course development of the effects of ethanol ingestion on choline oxidase

Male rats were fed a low-fat diet containing 36% of calories as ethanol, and the time-course development of the effects of ethanol on liver mitochondrial oxidation of choline was determined. Ethanol induced an increase in choline oxidase at days 2, 5 and 7 after being introduced into the diet. Due to an observed 32% increase in total fatty acids in the whole liver, defatted bovine serum albumin was added to the buffer used to homogenize the liver. The presence of bovine serum albumim resulted in a significant decrease in choline oxidase activity at days 2 and 5; however, ethanol still induced an increase in choline oxidase activity in these mitochondria. The total fatty acid concentration of mitochondria prepared in the absence of bovine serum albumin increased steadily until day 5; however, by day 7 the fatty acid concentration had returned to control levels. The addition of bovine serum albumin to the homogenization medium prevented the increase in the total amount of fatty acids. The fatty acid composition of the bovine serum albumin-treated mitochondria, however, was not different from the mitochondria is isolated in the absence of bovine serum albumin. Further, the addition of a free fatty acid to isolated mitochondrial preparations caused about a 100% increase in choline oxidase. These data are consistent with the idea that choline oxidase may be regulated to some extent by an influx or an increase in free fatty acids in the liver as a result of ethanol ingestion. Thus, a second mechanism has been described which contributes to the increase in choline oxidase after ethanol ingestion.

Lipid changes in roots of frost hardy and less hardy alfalfa varieties under hardening conditions

Root lipids of two alfalfa varieties, Rambler (frost hardy) and Caliverde (less hardy) were analyzed before and after controlled hardening. Total fatty acids, total linoleic acid, phosphatidylcholine, phosphatidylethanolamine and triglycerides increase in both varieties during hardening. The increase in total fatty acids and linoleic acid is greater in Rambler. Phosphatidylcholine and phosphatidylethanolamine increase more in Ramber while triglycerides rises more in Caliverde. Linoleic acid content of all classes increases more in Rambler than in Caliverde. The augmentation in phospholipid and linoleic acid content might therefore be related to frost hardening, but not the increase in triglycerides. These results suggest that cellular membranes are implicated in the mechanism of cold adaptation.

Influence of Simazine and Atrazine on Free Fatty Acid Content in Isolated Chloroplasts

Chloroplasts, isolated from fresh spinach (Spinacia oleracea L.) were treated with four concentrations of each 2-chloro-4,6-bis(ethylamino)-s-triazine (simazine) or 2-chloro-4-(ethylamino)-6-(isopropylamino)-s-triazine (atrazine) to determine the influence of these herbicides on the free fatty acid content in isolated chloroplasts. The treated chloroplast solutions were sampled at 0, 5, 15, 30, 60, and 120 min following treatment. Results indicated that most herbicide treatments increased free fatty acid content in isolated chloroplasts when compared with the zero concentration treatments. The increased fatty acid content was similar for most concentrations of simazine and atrazine. Results of individual fatty acid analyses indicated that the increase in total fatty acids was a result of increases in concentration of unsaturated rather than saturated fatty acids.

Effects of Nitrogen Limitation on the Growth and Composition of Unicellular Algae in Continuous Culture

Since fat accumulation takes place in many algae as a response to exhaustion of the nitrogen supply, it has been suggested that this may provide a means of enhancing the potential food value of algae. To test this possibility, chemostatic continuous cultures of Chlorella sorokiniana and Oocystis polymorpha were subjected to successive reductions in influent nitrogen. As cellular nitrogen content decreased from about 10 to 4%, oxygen evolution, carbon dioxide uptake, chlorophyll content, and tissue production were drastically reduced, but total lipid content was essentially unchanged. Caloric values and C, H, and N analyses suggested a moderate increase in carbohydrate content, but gas chromatographic analyses revealed no significant qualitative or quantitative changes in the fatty acid fraction. In batch-cultured cells, nitrogen could be reduced to 3% of dry weight, causing a concomitant increase in total fatty acids and pronounced changes in the composition of the fatty acid fraction. These results suggest that cellular nitrogen must fall to approximately 3% of dry weight before appreciable increases in lipid synthesis can occur. Cell nitrogen is then apparently completely bound in essential cell constituents, and carbon subsequently fixed is converted into lipid products. The findings indicate that nitrogen limitation may be useful in increasing the food quality of batch-cultured cells, but the technique has little value for continuous culture systems per se.

Effects of Nitrogen Limitation on the Growth and Composition of Unicellular Algae in Continuous Culture

Since fat accumulation takes place in many algae as a response to exhaustion of the nitrogen supply, it has been suggested that this may provide a means of enhancing the potential food value of algae. To test this possibility, chemostatic continuous cultures of Chlorella sorokiniana and Oocystis polymorpha were subjected to successive reductions in influent nitrogen. As cellular nitrogen content decreased from about 10 to 4%, oxygen evolution, carbon dioxide uptake, chlorophyll content, and tissue production were drastically reduced, but total lipid content was essentially unchanged. Caloric values and C, H, and N analyses suggested a moderate increase in carbohydrate content, but gas chromatographic analyses revealed no significant qualitative or quantitative changes in the fatty acid fraction. In batch-cultured cells, nitrogen could be reduced to 3% of dry weight, causing a concomitant increase in total fatty acids and pronounced changes in the composition of the fatty acid fraction. These results suggest that cellular nitrogen must fall to approximately 3% of dry weight before appreciable increases in lipid synthesis can occur. Cell nitrogen is then apparently completely bound in essential cell constituents, and carbon subsequently fixed is converted into lipid products. The findings indicate that nitrogen limitation may be useful in increasing the food quality of batch-cultured cells, but the technique has little value for continuous culture systems per se.

Effect of intra-arterial insulin on tissue cholesterol and fatty acids in alloxan-diabetic dogs.

Insulin and saline were injected into the right and left femoral arteries respectively of 19 alloxan-diabetes-mellitus dogs for 1 to 28 weeks. A significant increase of artery tissue cholesterol and total fatty acids was found on comparing the insulin-administered right leg with the saline-administered left leg. Similarly, a significant increase of total fatty acids in muscle was found on comparing the right with the left leg of the alloxan-diabetes mellitus dogs. No significant differences were observed in the normal animals when the insulin-injected side was compared with the noninjected.

THE INFLUENCE OF HYPOPHYSECTOMY, THYROIDECTOMY, AND OF BOTH HYPOPHYSECTOMY AND THYROIDECTOMY UPON THE FAT CONTENT OF THE LIVER OF THE DOG1

The control exercised by pituitary and thyroid glands upon lipid metabolism has been the subject of earlier reports from this laboratory (Chaikoff et al., 1936; Chaikoff et al., 1941; Entenman et al., 1942a and b). Hypophysectomy per se has but little effect on the levels of the blood lipids of the dog (Chaikoff et al., 1936). Provided caloric intake is not restricted, thyroidectomy, on the other hand, produces changes in the concentration of blood lipids of this animal (Chaikoff et al., 1941). Definite elevations in the levels of blood cholesterol esters were observed as early as 7 days after excision of the thyroid gland, and by the time 29 days had elapsed definite increases in total fatty acids were also found. Not all blood lipid constituents, however, responded to the same degree; phospholipids and free cholesterol seldom showed pronounced increases after thyroidectomy.

CHANGES IN LIPID CONTENT OF SERUM AND OF LIVER FOLLOWING BILATERAL RENAL ABLATION OR URETERAL LIGATION

1. In the dog and monkey bilateral nephrectomy or ureteral ligation results in a marked, progressive increase of total fatty acids, of free and esterified cholesterol, of phospholipid, and of free fat of serum. 2. No such changes follow unilateral nephrectomy, splenectomy, or fasting. 3. The increase after bilateral nephrectomy is not inhibited by glucose administration. 4. A marked increase of the phospholipid and a less significant elevation in cholesterol content of the liver accompanies this increase of serum lipids after bilateral nephrectomy.