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At least 19 recordsLinked to original sources
PubMed1976

Effect of different carbon sources on the biosynthesis of polyunsaturated fatty acids of alpha-linolenic acid family in culture of minimal deviation hepatoma 7288 C cells.

The effect of three different carbon sources on the biosynthesis of polyunsaturated fatty acids of the alpha-linolenic acid series was investigated in hepatoma tissue culture (HTC) cells. Alpha linolenic acid was converted to higher homologs by a desaturating route that synthetized mainly 18:4 (delta6, 9, 12, 15), 20:4 (delta8, 11, 14, 17) and 20:5 (delta5, 8, 11, 14, 17) and an elongating route that produced 20:3 (delta11, 14, 17) and 20:4 (delta5, 11, 14, 17) acids. "Fasting" decreased both biosynthetic routes whereas glucose reactivated only the elongating pathway. Lactabumin hydrolysate enhanced significantly only the desaturating route whereas glycerol was inactive. Glucose and aminoacids increased similarly the incorporation of labeled alpha linolenic acid in the cells. The results are independent of hormonal effects.

Carcinoma, Hepatocellular↗
PubMed1976

The action of insulin and dibutyryl cyclic AMP on the biosynthesis of polyunsaturated acids of alpha-linolenic acid family in HTC cells.

Incubation of HTC cells (7288 C) with 114C-alpha-linolenic acid in Swim's 77 medium during 24 hours converted the fatty acid to octadeca-6,9,12,15-tetraenoic acid, eicosa-11,14,17-trienoic acid, eicosa-8,11,14,17-tetraenoic acid, eicosa-5,11,14,17-tetraenoic acid, eicosa-5,8,11,14,17-pentaenoic acid and unsaturated acids of 22 carbons. The existence of two pathways was recognized: one initiated by a delta6-desaturation and the other by an elongation of alpha-linolenic acid. Incubation of the cells with insulin and dibutyryl cyclic AMP modified both pathways in different ways. HTC cells were sensitive to insulin which enhanced the desaturating route increasing eicosapentaenoic acid synthesis and depressed the elongating route decreasing eicosatrienoic acid. In an opposite way, dibutyryl cyclic AMP decreased eicosapentaenoic acid synthesis and increased eicosatrienoic acid.

Bucladesine↗
PubMed1978

[Effect of dietary alpha-linolenic acid on the conversion of linoleic and gamma-linolenic acids (1-14C) into arachidonates in rats in vivo].

The effects of alpha-linolenic acid (9-12-15 octadecadienoic) upon the conversion in vivo of [1-14C] linoleic acid and of [1-14C] gamma-linolenic acid into arachidonate have been studied in adult rats. The two tracers have been administered by stomach tubing and the amounts of [14C]-radioactivity incorporated into arachidonate in the liver, kidneys and whole rat have been measured 48 h later. Three experiments have been carried out on rats fed on alpha-linolenic acid containing diets prior to the radioactive tubing. In these diets, alpha-linolenic acid was brought either as ethyl ester or in the form of Primor oil (erucic acid free rapeseed oil). In all of them, the ratio alpha-linolenic acid: linoleic acid did not exceed 0.45. Control animals were fed, in the same conditions, ethyl oleate or peanut oil respectively. Comparing the alpha-linolenic acid fed-rats to the control animals, we were able to observe the following results: (1) The exogenous supplies of alpha-linolenic acid used in the diets have not brought about any significant alteration in the amounts (weights) of arachidonic acid present in the liver, kidneys and whole animal. (2) Using [1-14C] linoleic acid as a precursor, the amounts of [14C]-radioactivity incorporated into arachidonate in the same organs as well as in the whole rat have been significantly lowered by dietary alpha-linolenate. (3) alpha-Linolenate, on the contrary, had no significant effect upon the amounts of radioactivity incorporated into hepatic, renal and whole body arachidonate following the administration of [1-14C] gamma-linolenic acid. These results lead to the conclusion that alpha-linolenic acid, when present in the diet of rats at a limited, phyisological level, partly inhibits the desaturation of linoleic acid in vivo but does not affect the subsequent reactions in the biosynthesis of arachidonic acid.

Animals↗
PubMed1977

Incorporation and metabolism of stearic, oleic, linoleic and alpha-linolenic acids in minimal deviation hepatoma 7288 C cells.

Minimal Deviation Hepatoma 7288 C cells were cultured in confluent layer with labeled stearic, oleic, linoleic and alpha-linolenic acids. The kinetics of incorporation and conversion to higher homologs was studied. The maximum amounts incorporated in nmoles per mg of cellular protein for stearic, oleic, linoleic and alpha-linolenic acids were 39, 115.6, 90 and 230 respectively. alpha-linolenic acid was converted to octadeca-6,9,12,15-tetraenoic acid (18:1), eicosa-11,14,17-trienoic acid (20:3), eicosa-8,11,14,17 and 5,11,14,17-tetraenoic acids (20:4) and eicosa-5,8,11,14,17-pentaenoic acid (20:5), and also to myristic, palmitic, palmitoleic, stearic and oleic acids. By a mathematical approach, the endogenous pool size of alpha-linolenic acid available for conversion to eicosa-5,8,11,14,17-pentaenoic acid, were calculated. Both values decreased when the cells were preincubated with unlabeled alpha-linolenic acid.

Carcinoma, Hepatocellular↗
PubMed1977

Effect of "fasting" and different concentrations of glucose on alpha-linolenic acid metabolism in HTC cells. Correlation with the ultrastructural study.

HTC cells are able to convert alpha-linolenic acid into higher homologs by desaturating and elongating reactions. When the cells were cultured in a Krebs Ringer bicarbonate solution ("fasted cells") a decrease in both biosynthetic reactions took place. "Refeeding" the cells with Swim's 77 medium without glucose enhanced the biosynthesis of polyunsaturated fatty acids from alpa-linolenic acid family, but when glucose was added to the medium, alpha-linolenic acid was preferably elongated rather than converted into eicose-pentaenoic acid. The ultrastructural study revealed HTC cells with a simple cytoplasmic organization, showing little evidence of their origin from hepatocytes. The cells cultured in a complete medium appeared well preserved and were similar to those "fasted" for 12 hours and "refed" for another 12 hours using Swim's 77 medium without serum. The amount of glucose in the medium plays a role in preserving the cell structure. This effect does not occur if glucose is added in the absence of aminoacids and vitamins.

Carcinoma, Hepatocellular↗
PubMed1975

Effects of glucagon and dibutyryl adenosine 3', 5'-cyclic monophosphate on oxidative desaturation of fatty acids in the rat.

The present work was undertaken to study the effect of anti-insulinic and glycogenolytic factors on the oxidative desaturation of fatty acids. The effects of glucagon and dibutyryl cyclic AMP on the desaturation of linoleic acid to gamma-linolenic acid, alpha-linolenic acid to octadeca-6,9,12,15-tetraenoic acid, stearic acid to oleic acid, and eicosa-8,11,14-trienoic acid to eicosa-5,8,11,14-tetraenoic acid by rat liver microsomal preparations were investigated. Fasted rats had low desaturating activity, but refeeding a fat-free diet enhanced the activity. Administration of glucagon or dibutyryl cyclic AMP abolished the increase of the 6-desaturase activity elicited by refeeding. However, a similar effect on the 9-desaturase and 5-desaturase activity was not observed. The relationship between these effects and glucose metabolism is discussed.

Animals↗
PubMed1975

Comparative biosynthesis of polyethylenic fatty acids in Acanthamoeba castellanii and Ochromonas danica.

Acanthamoeba castellanii were incubated in vivo with 1(-14)C linoleic and 1(-14)C-alpha-linolenic acids. The incorporation of the acids into lipid fractions was studied. Labeling was found mainly in triglycerides and phospholipids. Homogenized cells and subcellular fractions separated by centrifugation were incubated with 1-14C-linoleic. 1-14C -alpha-linoleic and 1-14C eicosa-8,11-dienoic acids in the presence of NADH, ATP, and CoA. Different metabolic routes were demonstrated. omega3 and omega6 desaturases of the vegetal type, as well as a delta6 desaturation of alpha-linolenic acid of the animal type were present. The supernatant of 100000 x g contained both types of desaturating enzymes, whereas the corresponding particulated fraction was inactive. The ultrastructure of Acanthamoeba showed the endoplasmic reticulum with a poorly developed membrane component. The metabolic pathways found with Acanthamoeba were compared to Ochromonas danica incubated with linoleic acid in the light and in darkness. Desaturases typical of "vegetal" and "animal" pathways were found in both organisms. In both of them, alpha-linolenic and arachidonic acids could be synthetized. However, alpha-linolenic acid, typical of vegetal synthesis, was only stored in Ochromonas due to the presence of a photosynthetic machinery.

Adenosine Triphosphate↗
PubMed1976

Effect of epinephrine on the oxidative desaturation of fatty acids in the rat.

The effect of epinephrine on the oxidative desaturation of fatty acids by liver microsomal preparations of rats has been studied. Administration of epinephrine (1 mg/kg body weight) produced a significant decrease in desaturation of [l-14C]=linoleic acid to gamma-linolenic acid and of [L-14C]alpha-linolenic acid to actadeca-6,9,12,15-tetraenoic acid 12 hr after the infection. Lower doses produced a lesser effect on the delta6-desaturation activity. Epinephrine administration modified the V max of linoleic acid desaturation but not the K m. There was also a slight increase in palmityl desaturation activity. The effect of epinephrine on delta6-desaturation activity was postulated to be mediated through an enhancement of the intracellular cyclic AMP levels that lead to an increase of a glucose metabolite. This metabolite would inhibit delta6-desaturation activity.

Animals↗
PubMed2026

Multi-omics integration uncovers adaptive responses of stomach and pyloric ceca to artificial feed in mandarin fish (Siniperca chuatsi).

The mandarin fish, as an obligate piscivore, is highly dependent on live bait, which restricts its intensive aquaculture. Although domestication has enabled it to partially accept formulated diets, the tissue-specific molecular adaptation mechanisms of its digestive tract to artificial feed remain unclear. In this study, we conducted an integrated analysis of mandarin fish fed with live bait or artificial diet for three weeks, combining growth performance evaluation, gastric histology, and paired transcriptomic and metabolomic analyses of the stomach and pyloric ceca. AD feeding significantly improved growth performance, while histological examination revealed marked hyperplasia of the gastric mucosa and disorganized fold structures. Transcriptomic analysis identified 5065 and 3381 differentially expressed genes in the stomach and pyloric ceca, respectively. In the stomach, the artificial diet induced a glutathione-dependent antioxidant response, accompanied by glycolytic reprogramming and coordinated upregulation of genes in the extracellular matrix (ECM)-receptor interaction signaling pathway, including those encoding collagen, laminin, and integrin. In the pyloric ceca, the tricarboxylic acid (TCA) cycle and oxidative phosphorylation were broadly suppressed, whereas glycosaminoglycan degradation and lysosomal pathways were activated. Metabolomic analysis showed that gastric metabolites were enriched in vascular and inflammatory mediator pathways, while metabolites in the pyloric ceca were enriched in peroxisome proliferator-activated receptor (PPAR) signaling, sphingolipid signaling, and steroid hormone biosynthesis pathways. Following artificial diet feeding, integrated multi-omics analysis of the stomach revealed significant enrichment of pathways such as phospholipase D signaling, sphingolipid signaling, and arachidonic acid metabolism, accompanied by the accumulation of key metabolites including sphingosine-1-phosphate, 20-hydroxyeicosatetraenoic acid, and cellobiose. Integrated analysis of the pyloric ceca identified significantly altered pathways, including sphingolipid metabolism, alpha-linolenic acid metabolism, and glutathione metabolism, along with elevated levels of sphingosine-1-phosphate, sphingosine galactoside, and 9-hydroxy-12-oxo-10,15-octadecadienoic acid, as well as decreased glutathionylspermidine. These findings systematically unveil the tissue-specific molecular adaptation characteristics of the mandarin fish digestive tract in response to artificial feed, providing an important basis for understanding the molecular mechanisms of dietary adaptation in carnivorous fish and for optimizing artificial feed formulations.

Animals↗
PubMed2025

Assessing the causal effect of genetically predicted metabolites and metabolic pathways on vitiligo: Evidence from Mendelian randomization and animal experiments.

Vitiligo is a common chronic skin depigmentation disorder that seriously decreases the patients' overall quality of life. Human blood metabolites could contribute to unraveling the underlying biological mechanisms of vitiligo. We used GWAS summary statistics to assess the causal association between genetically predicted 1400 serum metabolites and vitiligo risk by Mendelian randomization (MR). Then, after constructing the mouse model of vitiligo, we did non-targeted metabolomics analysis on the mouse serum and validated MR's pathway enrichment results ulteriorly. In the initial phase, MR analysis revealed causative associations between 36 metabolites and vitiligo risk, including 8 metabolite ratios and 28 individual metabolites (19 known and 9 unknown metabolites). In the validation stage, 7 metabolites were successfully validated. Of the 28 individual metabolites, most are related to lipid metabolism. Genetically predicted higher 4-oxo-retinoic acid showed the strongest protective effect on vitiligo, while the most potent risk effect was the increase in quinate. The metabolites associated with vitiligo risk are mainly enriched in alpha-linolenic acid metabolism, linoleic acid metabolism, arginine biosynthesis and metabolism pathways, validated through the serum metabolomics of vitiligo mouse. By integrating genomics and metabolomics, this study provides new insights into the association between metabolites and vitiligo, highlighting the potential roles of specific metabolites in the pathogenesis of vitiligo. These metabolites associated with vitiligo could serve as new biomarkers, further research could help to reveal how these metabolites influence specific pathways in the development of vitiligo.

Animals↗
PubMed1977

Regulatory function of delta6 desaturate -- key enzyme of polyunsaturated fatty acid synthesis.

The delta6 desaturation of unsaturated acyl-CoA is the first reaction involved in the normal biosynthesis of all polyunsaturated fatty acids families in animal microsomes. Due to this key position it can regulate the biosynthesis of the fatty acids of the series. The reaction is modified by competition with substrates and products, ATP, and acyl-CoA acceptors. Dietary glucose and fructose inhibit the enzyme whereas protein diets and essential fatty acid deficient diets enhance the reaction independently of hormonal effects. The enzyme is sensitive to hormones concentration. Insulin enhance the reaction but the effect is eliminated by protein synthesis inhibition. Hyperglucemic hormones as glucagon, and epinephrine depress the activity of the delta6 desaturase by reactions triggers by an increase of cAMP concentration. The lateral relation of linoleic or alpha-linolenic microsomal elongation is insensitive to insulin, glucagon, epinephrine and protein. All these effects have been proved by either in vivo experiments or cell culture using linoleic or alpha-linolenic acids as substrates.

Animals↗
PubMed1978

Evidence for the different responses of delta9-, delta6- and delta5-fatty acyl-CoA desaturases to cytoplasmic proteins.

Microsomes prepared from the livers of 4-week-old rats were, after extraction with 0.1 M potassium phosphate buffer, pH 7.4, unable to catalyse either the delta6 desaturation of alpha-linolenic acid (9c.12c.15c., 18 : 3) into 6c.9c.12c.15c., 18 : 4 or the delta5 desaturation of eicosatrienoic acid (8c.11c.14c., 20 : 3) into arachidonic acid (5c.8c.11c.14c., 20 : 4). Both these enzymes only showed full activity after incubation of the microsomes with either the 100 000 X g supernatant fraction or with purified bovine catalase. Bovine serum albumin, while capable of restoring 50% of the delta5 desaturase activity has no effect on the delta6 desaturase. In contrast the delta9 desaturase activity of microsomes was never completely lost after extraction with buffer but could be stimulated by optimum concentrations of both bovine serum albumin and catalase. The significance of the different responses of the three desaturases to the cytoplasmic components is discussed.

8,11,14-Eicosatrienoic Acid↗
PubMed2026

EWAS in a polyphenol dense, DNA methylation-targeted, controlled diet and lifestyle study.

BACKGROUND: Dietary and lifestyle factors can influence DNA methylation patterns. We previously reported epigenetic age attenuation following a controlled study using an 8-week polyphenol-dense, DNA methylation-targeted diet and lifestyle intervention in healthy males (Methylation Diet and Lifestyle Study), with phytonutrient/polyphenol-rich foods (green tea, oolong tea, curcumin, garlic, and berries) being most predictive of this effect. METHODS: Here we conducted an epigenome-wide association study (EWAS) in 38 participants from the Methylation Diet and Lifestyle Study. The intervention included a dietary pattern intentionally rich in substrate and cofactor nutrients for methylation pathways, and components known to alter DNA-methyltransferase (DNMT) enzyme activity. In line with prior EWAS studies with small sample sizes where FDR-significant findings are unlikely, we used pre-specified nominal P-value thresholds (0.001, 0.0001) for the exploratory analyses. RESULTS: At P < 0.001 (unadjusted), 676 differentially methylated loci (DML) were identified in the intervention group versus 286 in controls. At P < 0.0001 (unadjusted), 50 DML were identified in the intervention group compared to 13 in controls. Fifteen DML were in transcription start site-proximal regions of genes including those involved in zinc homeostasis and nutrient sensing, development and pluripotency, proteostasis and genome stability, tumor suppression, and synaptic function. A group-by-time interaction analysis identified 70 intervention-specific DML at P < 0.0001, with nominal enrichment including autophagy, mTOR signaling, and chromatin remodeling pathways. A regional DMR analysis identified 128 within-group and 129 interaction-specific DMRs. DMR functional enrichment analyses revealed convergent nominal associations with lipid metabolism (alpha-linolenic acid, lipoic acid, biosynthesis of unsaturated fatty acids, PPAR signaling, cholesterol homeostasis), central energy metabolism (TCA cycle, glycolysis/gluconeogenesis, pentose phosphate, pyruvate), and nutrient sensing (PI3K-Akt, mTOR, AMPK, autophagy as well as other pathways). As expected for the limited cohort size and short intervention duration, none of the single CpG findings or enrichment analyses survived multiple test correction and are therefore considered exploratory and hypothesis-generating only. CONCLUSION: This EWAS identified a larger number of nominally changing CpGs in the intervention group compared to controls as well as biologically coherent methylation changes. These findings provide mechanistic hypotheses for previously observed epigenetic age attenuation. Replication in larger cohorts, longer intervention durations, and functional validation remain essential.

DNA methylation↗
PubMed1979

Relationship between essential fatty acid requirements of aquatic animals and the capacity for bioconversion of linolenic acid to highly unsaturated fatty acids.

1. [1-14C]linolenic acid was injected into the rainbow trout, Salmo gairdnerii, ayu, Plecoglossus altivelis, eel, Anguilla japonica, red sea bream, Chrysophrys major, rockfish, Sebastiscus marmoratus, globefish, Fugu rubripes rubripes and prawn, Penaeus japonicus (molting stage D"1-D2), and the bioconversion of linolenic acid (18:3 omega 3) to highly unsaturated fatty acids such as eicosapentaenoic (20:5 omega 3) and docosahexaenoic (22:6 omega 3) acids was investigated. 2. Linolenic acid was converted to 20:5 omega 3 and 22:6 omega 3 intensively in the rainbow trout, moderately in the ayu, eel and prawn, but slightly in the red sea bream, rockfish and globefish. 3. These results were discussed in relation to the essential fatty acid requirements of the aquatic animals.

Animals↗
PubMed1975

Biosynthesis of unsaturated fatty acids in cultured minimal deviations hepatoma 7288 C cells.

Minimal Deviation Hepatoma 7288 C cells were cultured in confluent layer with labeled linoleic, alpha-linolenic, eicosa-8,11,14-trienoic and stearic acids. The cells in culture preserved their ability to convert stearic acid to oleic acid. They also synthesized arachidonic acid from linoleic acid or eicosa-8,11,14-trienoic acid. The conversion was very low with linoleic acid and high with eicosatrienoic acid. Eicosapentaenoic acid and other homologs of the alpha-linolenic acid family were synthesized from alpha-linolenic acid. The biosynthetic patterns were the cells was modified by the fatty acid composition of the media.

Carcinoma, Hepatocellular↗
PubMed2025

The 13-lipoxygenase GmLOX6 is involved in JA biosynthesis and serves as a positive regulator of salt stress tolerance in soybean.

Salinity represents a major abiotic stressor that significantly impairs soybean growth and yield. Although jasmonic acid (JA) has been firmly established as a key regulator of plant defense against salt stress, the precise functions of lipoxygenase (LOX) genes responsible for initiating JA biosynthesis remain poorly defined. Here, a comprehensive genome-wide analysis of the soybean LOX gene family was performed, and a detailed functional characterization of GmLOX6 was carried out. Subcellular localization confirmed that GmLOX6 is targeted to chloroplasts, while enzymatic assays demonstrated that it acts as a 13-LOX enzyme with a strong preference for &#x3b1;-linolenic acid as substrate. To clarify its role under salt stress, we generated both overexpression and CRISPR/Cas9-mediated knockout lines of soybean. Phenotypic and molecular evaluations revealed that GmLOX6 facilitates JA production under salt stress, thereby contributing to enhanced JA accumulation. This elevation in JA levels was associated with improved salt tolerance through multiple physiological adaptations, including the activation of antioxidant enzymes for the detoxification of reactive oxygen species (ROS), enhanced Na+ extrusion to preserve ionic balance, and reinforced membrane stability. Moreover, GmRWP-RK11 was identified as a transcriptional repressor of GmLOX6. Functional disruption of GmRWP-RK11 via CRISPR/Cas9 conferred greater salt tolerance, further supporting its negative regulatory role. Collectively, these findings uncover a novel regulatory axis in which GmLOX6-mediated JA biosynthesis enhances soybean resistance to salinity through modulation of ROS homeostasis and Na+ transport. These insights provide an expanded understanding of the transcriptional and biochemical mechanisms underpinning JA-driven stress adaptation in soybean.

Glycine max↗