Extremely rapid effects of polyunsaturated fatty acids and N-acetylglucosamine on free-radical metabolism in cultured potato plant cells

2000 ◽  
Vol 28 (6) ◽  
pp. 865-867 ◽  
Author(s):  
P. A. Kashulin ◽  
M. N. Merzlyak ◽  
P. M. Zhiboedov ◽  
V. K. Zhirov
Keyword(s):  
Fatty Acids ◽  
Solanum Tuberosum ◽  
Fatty Acid ◽  
Free Radical ◽  
Cell Cultures ◽  
Plant Cells ◽  
Dichlorofluorescin Diacetate ◽  
Radical Generation ◽  
Defensive Mechanisms ◽  
Stimulation Of

The effects of arachidonic and linoleic acids, separately and in co-operation with N-acetylglucosamine oligomers, on Solanum tuberosum plant suspension cell cultures were investigated in terms of the fluorescent oxygen-activated-species-sensitive dye 2Î,7Î-dichlorofluorescin diacetate. The inductors used triggered extremely rapid (within 2–10 min) generation of H2O2 in the cells; the majority was expressed in cultures treated with combined polyunsaturated fatty acid and N-acetylglucosamine oligomers. The stimulation of free-radical generation may be related to defensive mechanisms modulating a plant-pathogenicmicro-organism interaction.

scholarly journals The regulation of glyceride synthesis in isolated white-fat cells. The effects of palmitate and lipolytic agents

1972 ◽  
Vol 128 (5) ◽  
pp. 1057-1067 ◽  
Author(s):  
E. D Saggerson
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Free Fatty Acids ◽  
Fatty Acid Synthesis ◽  
Acid Synthesis ◽  
Fat Cells ◽  
Glyceride Synthesis ◽  
Glucose Incorporation ◽  
High Concentrations ◽  
Stimulation Of

1. 0.5mm-Palmitate stimulated incorporation of [U-14C]glucose into glyceride glycerol and fatty acids in normal fat cells in a manner dependent upon the glucose concentration. 2. In the presence of insulin the incorporation of 5mm-glucose into glyceride fatty acids was increased by concentrations of palmitate, adrenaline and 6-N-2′-O-dibutyryladenosine 3′:5′-cyclic monophosphate up to 0.5mm, 0.5μm and 0.5mm respectively. Higher concentrations of these agents produced progressive decreases in the rate of glucose incorporation into fatty acids. 3. The effects of palmitate and lipolytic agents upon the measured parameters of glucose utilization were similar, suggesting that the effects of lipolytic agents are mediated through increased concentrations of free fatty acids. 4. In fat cells from 24h-starved rats, maximal stimulation of glucose incorporation into fatty acids was achieved with 0.25mm-palmitate. Higher concentrations of palmitate were inhibitory. In fat cells from 72h-starved rats, palmitate only stimulated glucose incorporation into fatty acids at high concentrations of palmitate (1mm and above). 5. The ability of fat cells to incorporate glucose into glyceride glycerol in the presence of palmitate decreased with increasing periods of starvation. 6. It is suggested that low concentrations of free fatty acids stimulate fatty acid synthesis from glucose by increasing the utilization of ATP and cytoplasmic NADH for esterification of these free fatty acids. When esterification of free fatty acids does not keep pace with their provision, inhibition of fatty acid synthesis occurs. Provision of free fatty acids far in excess of the esterification capacity of the cells leads to uncoupling of oxidative phosphorylation and a secondary stimulation of fatty acid synthesis from glucose.

Effect of glucose concentration in the growth medium on the synthesis of fatty acids by the yeast Candida bogoriensis

1982 ◽  
Vol 28 (2) ◽  
pp. 223-230 ◽  
Author(s):  
Adrian J. Cutler ◽  
Robley J. Light
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Free Fatty Acid ◽  
Yeast Extract ◽  
Fatty Acid Synthesis ◽  
Acid Synthesis ◽  
Glucose Medium ◽  
Triglyceride Fraction ◽  
Low Glucose ◽  
Stimulation Of

The yeast Candida bogoriensis produced large quantities of an extracellular glycolipid, the diacetyl sophoroside of 13-hydroxydocosanoic acid, when grown on a standard glucose rich medium (3% glucose, 0.15% yeast extract), but not when grown on a low glucose medium (0.5% glucose, 0.4% yeast extract) (A. J. Cutler and R. J. Light. 1979. J. Biol. Chem. 254: 1944–1950). Glucose levels also affected the quantity and distribution of the free fatty acid and triglyceride fractions synthesized by this organism. Cells grown on the low glucose medium contained palmitate and stearate as the major fatty acids in these two fractions, and a 3-h incubation with [1-14C]acetate led primarily to the labeling of these two acids. Cells grown on the standard enriched glucose medium contained relatively less stearate and more behenate than the low glucose grown cells, and the incorporation of [1-14C]acetate into stearate was decreased, while that into behenate was increased.Supplementation of low glucose grown cells with glucose led to a rapid stimulation of fatty acid synthesis, primarily palmitate and stearate in the free fatty acid fraction and stearate in the triglyceride fraction. Total triglyceride began to increase a few hours after supplementation, but synthesis of the extracellular glycolipid, and hence 13-hydroxydocosanoic acid, did not occur until 12–24 h after supplementation. The stimulation by glucose of long chain fatty acid synthesis in C. bogoriensis was therefore a process distinct from the glucose stimulation of palmitate and stearate synthesis, though the two events may be causally related.

Stimulation of Strontium Accumulation in Linoleate-Enriched Saccharomyces cerevisiae Is a Result of Reduced Sr2+ Efflux

1999 ◽  
Vol 65 (3) ◽  
pp. 1191-1197 ◽  
Author(s):  
Simon V. Avery ◽  
Shareeka L. Smith ◽  
A. Mohamad Ghazi ◽  
Michael J. Hoptroff
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Fatty Acids ◽  
Plasma Membrane ◽  
Fatty Acid ◽  
Atpase Inhibitor ◽  
Calmodulin Antagonist ◽  
Wide Range ◽  
Fatty Acid Supplement ◽  
Accumulation Ability ◽  
Stimulation Of

ABSTRACT The influence of modified plasma membrane fatty acid composition on cellular strontium accumulation in Saccharomyces cerevisiaewas investigated. Growth of S. cerevisiae in the presence of 1 mM linoleate (18:2) (which results in 18:2 incorporation to ∼70% of total cellular and plasma membrane fatty acids, with no effect on growth rate) yielded cells that accumulated Sr2+ intracellularly at approximately twice the rate ofS. cerevisiae grown without a fatty acid supplement. This effect was evident over a wide range of external Sr2+concentrations (25 μM to 5 mM) and increased with the extent of cellular 18:2 incorporation. Stimulation of Sr2+accumulation was not evident following enrichment of S. cerevisiae with either palmitoleate (16:1), linolenate (18:3) (n-3 and n-6 isomers), or eicosadienoate (20:2) (n-6 and n-9 isomers). Competition experiments revealed that Ca2+- and Mg2+-induced inhibition of Sr2+ accumulation did not differ between unsupplemented and 18:2-supplemented cells. Treatment with trifluoperazine (TFP) (which can act as a calmodulin antagonist and Ca2+-ATPase inhibitor), at a low concentration that precluded nonspecific K+ efflux, increased intracellular Sr2+ accumulation by approximately 3.6- and 1.4-fold in unsupplemented and 18:2-supplemented cells, respectively. Thus, TFP abolished the enhanced Sr2+ accumulation ability of 18:2-supplemented cells. Moreover, the rate of Sr2+release from Sr2+-loaded fatty acid-unsupplemented cells was found to be at least twice as great as that from Sr2+-loaded 18:2-enriched cells. The influence of enrichment with other fatty acids on Sr2+ efflux was variable. The results reveal an enhanced Sr2+ accumulation ability of S. cerevisiae following 18:2-enrichment, which is attributed to diminished Sr2+ efflux activity in these cells.

Eicosapentaenoic and dihomo gamma linolenic acid metabolism by cultured rat mesangial cells

1989 ◽  
Vol 256 (1) ◽  
pp. C101-C108 ◽  
Author(s):  
L. A. Scharschmidt ◽  
N. B. Gibbons ◽  
R. Neuwirth
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Acid Metabolism ◽  
Mesangial Cells ◽  
Gamma Linolenic Acid ◽  
Significant Extent ◽  
Glomerular Function ◽  
Fatty Acid Release ◽  
Acid Release ◽  
Stimulation Of

To better understand the effects of dietary fatty acid manipulations on glomerular function, we compared mesangial incorporation, release, and metabolism of arachidonic (AA), eicosapentaenoic (EPA), and dihomo gamma linolenic (DHG) acids. We found marked differences in mesangial handling of these fatty acids. AA was incorporated into lipids of mesangial cells much more rapidly than EPA or DHG. Ionophore-induced stimulation of fatty acid release from mesangial cells prelabeled with [14C]AA, [14C]EPA, or [14C]DHG caused a release of labeled AA greater than DHG much less than EPA, respectively. Preloading mesangial cells with DHG or EPA for 24 h reduced subsequent basal, ionophore-, and hormone-stimulated prostaglandin E2 (PGE2) synthesis. Finally, unlike AA, neither EPA nor DHG was converted to a significant extent by mesangial cyclooxygenase or lipoxygenase. Thus the mesangial metabolism of DHG and EPA differs both quantitatively and qualitatively from that of AA. Furthermore, EPA and DHG inhibit metabolism of AA at the level of mesangial cyclooxygenase.

scholarly journals Diurnal variations in the effects of an unsaturated-fat-containing diet on fatty acid and cholesterol synthesis in rat hepatocytes

1986 ◽  
Vol 239 (3) ◽  
pp. 617-623 ◽  
Author(s):  
G F Gibbons ◽  
C R Pullinger
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Carbon Flux ◽  
Cholesterol Synthesis ◽  
Corn Oil ◽  
Total Carbon ◽  
Standard Diet ◽  
Dark Phase ◽  
Fat Feeding ◽  
Stimulation Of

Rats were fed ad libitum on either a standard high-carbohydrate diet, or a standard diet supplemented with 15% corn oil. Hepatocytes were prepared either during the light phase (L2-hepatocytes) or during the dark phase (D6-hepatocytes) of the diurnal cycle. In hepatocytes from rats fed on the fat-containing diet, fatty acid synthesis (lipogenesis) was suppressed to a much greater extent at D6 than at L2. The magnitude of the increase in plasma-free fatty acid concentration was similar at the two times of day. The rate of cholesterol synthesis was also significantly suppressed in the D6- but not in the L2-hepatocytes. This differential inhibition resulted in the abolition of the normal diurnal rhythm of cholesterogenesis. The initial activity of 3-hydroxy-3-methylglutaryl-CoA reductase in hepatocytes was also suppressed by corn-oil feeding at D6 but not at L2. In D6-hepatocytes, the inhibitory effect of the high-fat diet on the conversion of lactate into cholesterol and fatty acids was greater than that on total carbon flux into these substances for all endogenous sources. Despite this, under these conditions a high concentration of lactate and pyruvate resulted in a several-fold stimulation of total carbon flux into fatty acids. In hepatocytes prepared at L2, fat-feeding had little effect on the degree of stimulation of lipogenesis by insulin or inhibition by glucagon. However, at D6, fat-feeding blunted the response of lipogenesis to both these hormones.

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