Synthesis Of Long-chain Fatty Acids Research Articles

Transcriptome Profiling Reveals Candidate Genes Related to Stipe Gradient Elongation of Flammulina filiformis.

Stipe gradient elongation is an important and remarkable feature in the development of most mushroom fruiting bodies. However, its molecular mechanism has rarely been described. Here, the decreasing trend of stipe elongation and increasing trend of cell length in a gradient from the top to the base of the stipe were determined in a model basidiomycete mushroom: Flammulina filiformis. According to RNA-seq results, 1409 differentially expressed genes (DEGs) were identified among elongation region (ER), transition region (TR), and stable region (SR) samples, including 26 transcription factors (TFs). Based on Short Time-series Expression Miner (STEM) clustering of DEGs, clusters 1 and 3, with obvious expression trends that were consistent with or in contrast to the elongation rate, were screened. The cluster 1 DEGs were mainly involved in the GO cellular component category and KEGG genetic information processing class; however, the cluster 3 DEGs were mainly involved in metabolic processes. Furthermore, qRT-PCR confirmed that key genes of the long-chain fatty acid synthesis pathway were involved in stipe gradient elongation and regulated by NADPH oxidase-derived ROS signaling molecules. These findings provide an essential basis for understanding the molecular mechanism of stipe gradient elongation.

Effectiveness of using the mixtures of herbicides flumioxazine and fluorochloridone in sunflower crops

Aim. This work is devoted to the search for potential partners for the integrated application of flumioxazine in sunflower crops. This herbicide is an inhibitor of protoporphyrinogen oxidase (PPO) in weed plants. The resistance to this class of herbicides is not yet common today, compared to other classes. Therefore, the work is aimed at de- veloping flumioxazine-based herbicide compositions that effectively prevent the emergence of herbicide-resistant weed biotypes. Methods. The interaction effects, weed control efficiency, and crop selectivity were studied when flumioxazine was used in the mixtures with herbicides acetochlor and propisochlor (long-chain fatty acid synthesis (LCFAS) inhibitors), promethrin (electron transport (ET) inhibitor in photosystem 2 (PS 2) of chloroplasts) and fluorochloridone (inhibitor of carotenoid synthesis by blocking the activity of phytoendesaturases (PDS)) both in the experiments on sunflower crops and in greenhouse experiments using the model objects. Results. The studies have shown that when flumioxazine is applied with the ET inhibitor, promethrin, the interaction is antagonistic, resulting in poor weed control efficiency and sunflower yield decrease. The tank mixtures of flumioxazine with LCFAS inhibitors acetochlor and propisochlor provide high weed control efficiency but are low in selectivity for sunflowers. The interaction between flumioxazine and fluorochloridone within the recommended application rates is additive. The tank mixture of flumioxazine and fluorochloridone herbicides at the application rates of 55 and 500 g/ha, respectively, is selective for sunflowers. In terms of control efficiency of annual dicotyledons, this mixture of herbicides exceeded, and in terms of control efficiency of annual cereal weed species was only slightly inferior to the control integrated herbicide (metolachlor + terbuthylazine). In these application rates, flumioxazine and fluo- rochloridone provided sunflower yield on par with this complex herbicide. Сonclusions. Among the investigated herbicides, the optimal partner of flumioxazine for complex use in sunflower crops was the herbicide, inhibitor PDS, fluorochloridone. Given that flumioxazine and fluorochloridone differ in their phytotoxicity mechanisms but share a common spectrum of controlled weed species, the use of a mixture of these herbicides is a factor that minimizes the likelihood of the emergence of herbicide-resistant weed biotypes.

Utilization of marine diatom Thalassiosira weissflogii as a feed additive in seawater-tolerant Nile tilapia (Oreochromis niloticus, Linnaeus 1758) strain

The low omega-3 content of tilapia flesh, when compared to marine fish, affects its marketability. In marine animals, the highly unsaturated fatty acids (HUFAs) can be linked to the oil produced by marine diatoms. Among the marine diatoms, the genusThalassiosirais known to exhibit high content of HUFAs such as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). Thus, in this study, the use of marine diatomThalassiosira weissflogiias a dietary additive in the seawater-tolerant Nile Tilapia strain was evaluated. One hundred ninety-two, 1.40 ± 0.05g seawater tilapia were randomly allocated into 4 treatment groups in 4 replicates. The first treatment group was fed with a control diet (D0), without the diatoms while treatments 1, 2, and 3 were each fed with diets supplemented withT. weissflogiipaste at 2.55% (D1), 6% (D2), and 12% (D3), respectively for 60 days. The diets were isonitrogenous, isolipodic and the omega-3 and omega-6 requirements were satisfied. Results demonstrated that D1 had the highest percent weight gain among treatments. Although not significantly different, other parameters such as percent survival, specific growth rate (SGR), protein efficiency ratio (PER), feed conversion ratio (FCR), and feed intake had desirable results in D1. The proximate composition of seawater tilapia showed that % crude protein was highest in D0 but % crude lipid was highest in D1. The fatty acid composition of tilapia in D1 had the highest omega-3 content at 9.29 mg/g tissue and also had the highest n3:n6 at 2.19. Muscle growth-related genes (MyoDandMYG) were up-regulated while liver genes involved in long-chain polyunsaturated fatty acid synthesis (oni-fads2andelvol5) were down-regulated in D1 as compared to D0. Feeding the diatom-supplemented diet to tilapia had no significant effects on hepatic cells and intestinal morphology. The results suggested that a 2.55% supplementation dose ofT. weissflogiicould promote growth and enhance the tissue content of omega-3 fatty acids of the seawater strainOreochromis niloticus.

Broiler meat fatty acids composition, lipid metabolism, and oxidative stability parameters as affected by cranberry leaves and walnut meal supplemented diets

A randomized complete block with a 2 × 3 factorial arrangement was used to design a nutrition experiment conducted for the evaluation of the relation between walnut meal (WM—6% inclusion rate) and cranberry leaves (CL—1% and 2% inclusion rate) supplements and their effects on tissue lipid profile, lipid metabolism indices and oxidative stability of meat. Semi-intensive system conditions were simulated for 240 Ross 308 broilers and the animals were reared on permanent shave litter in boxes of 3 m2 (40 broilers / each group, housed in a single box). The current study results showed that the diets enriched in linolenic acid (LNA) (WM diets) led to broilers meat enriched in LNA, but the synthesis of long-chain omega-3 polyunsaturated fatty acids (LC n-3 PUFA) was stimulated when the diets were supplemented with a natural antioxidants source (CL diets). The CL diet also exhibited the most powerful effect in counteracting the oxidative processes of meat.

Genome-Wide Association Analysis Reveals Novel Loci Related with Visual Score Traits in Nellore Cattle Raised in Pasture-Based Systems.

Body conformation traits assessed based on visual scores are widely used in Zebu cattle breeding programs. The aim of this study was to identify genomic regions and biological pathways associated with body conformation (CONF), finishing precocity (PREC), and muscling (MUSC) in Nellore cattle. The measurements based on visual scores were collected in 20,807 animals raised in pasture-based systems in Brazil. In addition, 2775 animals were genotyped using a 35 K SNP chip, which contained 31,737 single nucleotide polymorphisms after quality control. Single-step GWAS was performed using the BLUPF90 software while candidate genes were identified based on the Ensembl Genes 69. PANTHER and REVIGO platforms were used to identify key biological pathways and STRING to create gene networks. Novel candidate genes were revealed associated with CONF, including ALDH9A1, RXRG, RAB2A, and CYP7A1, involved in lipid metabolism. The genes associated with PREC were ELOVL5, PID1, DNER, TRIP12, and PLCB4, which are related to the synthesis of long-chain fatty acids, lipid metabolism, and muscle differentiation. For MUSC, the most important genes associated with muscle development were SEMA6A, TIAM2, UNC5A, and UIMC1. The polymorphisms identified in this study can be incorporated in commercial genotyping panels to improve the accuracy of genomic evaluations for visual scores in beef cattle.

Metabolomic profiling of triple negative breast cancer cells suggests that valproic acid can enhance the anticancer effect of cisplatin.

Cisplatin is an effective chemotherapeutic agent for treating triple negative breast cancer (TNBC). Nevertheless, cisplatin-resistance might develop during the course of treatment, allegedly by metabolic reprograming, which might influence epigenetic regulation. We hypothesized that the histone deacetylase inhibitor (HDACi) valproic acid (VPA) can counter the cisplatin-induced metabolic changes leading to its resistance. We performed targeted metabolomic and real time PCR analyses on MDA-MB-231 TNBC cells treated with cisplatin, VPA or their combination. 22 (88%) out of the 25 metabolites most significantly modified by the treatments, were acylcarnitines (AC) and three (12%) were phosphatidylcholines (PCs). The most discernible effects were up-modulation of AC by cisplatin and, contrarily, their down-modulation by VPA, which was partial in the VPA-cisplatin combination. Furthermore, the VPA-cisplatin combination increased PCs, sphingomyelins (SM) and hexose levels, as compared to the other treatments. These changes predicted modulation of different metabolic pathways, notably fatty acid degradation, by VPA. Lastly, we also show that the VPA-cisplatin combination increased mRNA levels of the fatty acid oxidation (FAO) promoting enzymes acyl-CoA synthetase long chain family member 1 (ACSL1) and decreased mRNA levels of fatty acid synthase (FASN), which is the rate limiting enzyme of long-chain fatty acid synthesis. In conclusion, VPA supplementation altered lipid metabolism, especially fatty acid oxidation and lipid synthesis, in cisplatin-treated MDA-MB-231 TNBC cells. This metabolic reprogramming might reduce cisplatin resistance. This finding may lead to the discovery of new therapeutic targets, which might reduce side effects and counter drug tolerance in TNBC patients.

ELOVL gene family plays a virtual role in response to breeding selection and lipid deposition in different tissues in chicken (Gallus gallus)

BackgroundElongases of very long chain fatty acids (ELOVLs), a family of first rate-limiting enzymes in the synthesis of long-chain fatty acids, play an essential role in the biosynthesis of complex lipids. Disrupting any of ELOVLs affects normal growth and development in mammals. Genetic variations in ELOVLs are associated with backfat or intramuscular fatty acid composition in livestock. However, the effects of ELOVL gene family on breeding selection and lipid deposition in different tissues are still unknown in chickens.ResultsGenetic variation patterns and genetic associations analysis showed that the genetic variations of ELOVL genes were contributed to breeding selection of commercial varieties in chicken, and 14 SNPs in ELOVL2-6 were associated with body weight, carcass or fat deposition traits. Especially, one SNP rs17631638T > C in the promoter of ELOVL3 was associated with intramuscular fat content (IMF), and its allele frequency was significantly higher in native and layer breeds compared to that in commercial broiler breeds. Quantitative real-time PCR (qRT-PCR) determined that the ELOVL3 expressions in pectoralis were affected by the genotypes of rs17631638T > C. In addition, the transcription levels of ELOVL genes except ELOVL5 were regulated by estrogen in chicken liver and hypothalamus with different regulatory pathways. The expression levels of ELOVL1-6 in hypothalamus, liver, abdominal fat and pectoralis were correlated with abdominal fat weight, abdominal fat percentage, liver lipid content and IMF. Noteworthily, expression of ELOVL3 in pectoralis was highly positively correlated with IMF and glycerophospholipid molecules, including phosphatidyl choline, phosphatidyl ethanolamine, phosphatidyl glycerol and phospholipids inositol, rich in ω-3 and ω-6 long-chain unsaturated fatty acids, suggesting ELOVL3 could contribute to intramuscular fat deposition by increasing the proportion of long-chain unsaturated glycerophospholipid molecules in pectoralis.ConclusionsIn summary, we demonstrated the genetic contribution of ELOVL gene family to breeding selection for specialized varieties, and revealed the expression regulation of ELOVL genes and their potential roles in regulating lipid deposition in different tissues. This study provides new insights into understanding the functions of ELOVL family on avian growth and lipid deposition in different tissues and the genetic variation in ELOVL3 may aid the marker-assisted selection of meat quality in chicken.

Heterologous expression, purification, and partial characterisation of the apicoplast protein 3-oxoacyl-[acyl-carrier-protein] reductase from Toxoplasma gondii

Recombinant expression and purification of proteins have become a staple of modern drug discovery as it enables more precise in vitro analyses of drug targets, which may help obtain biochemical and biophysical parameters of a known enzyme and even uncover unknown characteristics indicative of novel enzymatic functions. Such information is often necessary to prepare adequate screening assays and drug-discovery experiments in general. Toxoplasma gondii is an obligate protozoan parasite that is a member of the phylum Apicomplexa, can develop several neuro-degenerative symptoms and, in specific cases, certain death for human hosts. Its relict non-photosynthetic plastid, the apicoplast, harbours a unique de novo long-chain fatty acid synthesis pathway of a prokaryotic character, FASII. The FASII pathway shows plasticity and, is essential for many intracellular and membranal components, along with fatty acid uptake via salvaging from the host, therefore, its disruption causes parasite death. TgFabG, a FASII enzyme responsible for a single reduction step in the pathway, was recombinantly expressed, purified and biochemically and biophysically characterised in this study. The bioengineering hurdle of expressing the recombinant gene of a eukaryotic, signal peptide-containing protein in a prokaryotic system was overcome for the apicomplexan enzyme TgFabG, by truncating the N-terminal signal peptide. TgFabG was ultimately recombinantly produced in a plasmid expression vector from its 1131 base pair gene, purified as 260 and 272 amino acid proteins using a hexahistidine (6 × Histag) affinity chromatography and its biochemical (enzyme activity and kinetics) and biophysical characteristics were analysed in vitro.

Time-Restricted Feeding Could Not Reduce Rainbow Trout Lipid Deposition Induced by Artificial Night Light.

Artificial night light (ALAN) could lead to circadian rhythm disorders and disrupt normal lipid metabolism, while time-restricted feeding (TRF) could maintain metabolic homeostasis. In mammals, TRF has been demonstrated to have extraordinary effects on the metabolic regulation caused by circadian rhythm disorders, but studies in lower vertebrates such as fish are still scarce. In this study, the impacts of ALAN on the body composition and lipid metabolism of juvenile rainbow trout were investigated by continuous light (LL) exposure as well as whether TRF could alleviate the negative effects of LL. The results showed that LL upregulated the expression of lipid synthesis (fas and srebp-1c) genes and suppressed the expression of lipid lipolysis (pparβ, cpt-1a, and lpl) genes in the liver, finally promoting lipid accumulation in juvenile rainbow trout. However, LL downregulated the expression of genes (Δ6-fad, Δ9-fad, elovl2, and elovl5) related to long-chain polyunsaturated fatty acid (LC-PUFA) synthesis, resulting in a significant decrease in the proportion of LC-PUFA in the dorsal muscle. In serum, LL led to a decrease in glucose (Glu) levels and an increase in triglyceride (TG) and high-density lipoprotein cholesterol (H-DLC) levels. On the other hand, TRF (mid-dark stage feeding (D)) and mid-light stage feeding (L)) upregulated the expression of both the lipid synthesis (srebp-1c and pparγ), lipolysis (pparα, pparβ, and cpt-1a), and lipid transport (cd36/fat and fatp-1) genes, finally increasing the whole-body lipid, liver protein, and lipid content. Meanwhile, TRF (D and L groups) increased the proportion of polyunsaturated fatty acid (PUFA) and LC-PUFA in serum. In contrast, random feeding (R group) increased the serum Glu levels and decreased TG, total cholesterol (T-CHO), and H-DLC levels, suggesting stress and poor nutritional status. In conclusion, ALAN led to lipid accumulation and a significant decrease in muscle LC-PUFA proportion, and TRF failed to rescue these negative effects.

Changes in volatile and fatty acid compositions of selected microalgal suspensions with high pressure homogenization

This is the first report on the fatty acid and volatile analysis of high pressure homogenization (HPH)-treated microalgal suspensions using chemometrics methods to increase insight into the complex (bio)chemical changes. Four microalgal suspensions, namely Arthrospira , Isochrysis , Nannochloropsis , and Tetraselmis species, were processed by HPH at 300, 600, and 900 bar. While cell disruption due to HPH seemed to have a minimal impact on the fatty acid profile, the high number of discriminating volatiles suggest several (bio)chemical reactions that the treatment may have triggered. Alterations in terpene and ketones indicate the induction of carotenoid degradation. Lipid oxidation could also have occurred during HPH, as noted in the changes in furans in Arthrospira sp. and aldehydes in Nannochloropsis sp. and Tetraselmis sp. Maillard reaction may have likewise been triggered by HPH as shown by the pyrazines in Arthrospira sp. and Tetraselmis sp. Sulphur compounds were only significantly changing in Isochrysis sp. and are typically associated with the degradation of sulphur-containing amino acids. The abundance of hydrocarbons as discriminant volatiles suggests that HPH can induce the synthesis of long-chain fatty acids. This study provides insight into how the volatile profile of microalgae can potentially be manipulated by applying specific pressure levels of HPH. • The effect of HPH on the volatile and fatty acid profile was investigated. • HPH (especially at 900 bar) modified the volatile fraction of microalgal suspensions. • Changes in furans and pyrazines show a possible effect on the Maillard reactions. • HPH triggered the degradation of sulphur-containing amino acids and carotenoids. • A microalgal volatile profile can be modified by applying specific pressure-levels.

Trans Fatty Acids Content in Whole-Day Diets Intended for Pregnant and Breastfeeding Women in Gynaecological and Obstetric Wards: Findings from the Study under the "Mum's Diet" Pilot Program in Poland.

Trans fatty acids (TFAs) have been proven to have an adverse effect on human health by interfering with n-3 long-chain polyunsaturated fatty acids (n-3 LC-PUFA) synthesis. LC-PUFA n-3 are necessary for the development and maturation of the nervous system and retina during the prenatal period and infancy. TFAs are not synthesized de novo in the human body. Their presence in body fluids arises from the diet. The aim of our study was to determine the content of TFAs in individual meals and in a whole-day hospital diet intended for pregnant and breastfeeding women. Samples were collected from six different hospitals in Poland which voluntarily applied to the “Mum’s Diet” Pilot Program. The content of fatty acids, including TFAs, was determined by gas chromatography coupled with mass spectrometry (GC-MS). The TFAs content in the whole-day hospital diets ranged from 3.86 to 8.37% of all fatty acids (% wt/wt). Food products served for elevenses and afternoon snacks contributed the highest amounts of TFAs. These mainly included dairy products containing TFAs of natural origins. The estimated average intake of TFAs with the hospital diet was 0.72 g/person/day (range: 0.34–1.16 g/person/day) and did not exceed the maximum level of 1% of dietary energy recommended by the World Health Organization.

Cysteine protected cells from H2O2-induced damage and promoted long-chain fatty acids synthesis in vivo to improve γ-aminobutyric acid production in Levilactobacillus brevis.

Levilactobacillus brevis NPS-QW-145 isolated from kimchi is deficient in glutamate dehydrogenase-encoding gene (gdhA) to form glutamate, hence it required exogenous supplementation of glutamate/monosodium glutamate (MSG) for decarboxylation reaction to produce γ-aminobutyric acid (GABA). However, GABA conversion rate from MSG was relatively low. The individual effect of 20 amino acids on regulating GABA biosynthesis was investigated. Cysteine was selected to significantly improve GABA production from MSG. It was found that Lb. brevis was capable of producing H2O2, cysteine protected Lb. brevis against H2O2-induced oxidative damage to increase cell viability for the enhancement of GABA production. Moreover, cysteine promoted glucose consumption to produce acetyl-CoA for synthesizing long-chain fatty acids to significantly up-regulate GABA biosynthesis. These findings deciphered antioxidative capability of cysteine in Lb. brevis 145 and provided a theoretical basis for fatty acids synthesis-mediated GABA synthesis in Lb. brevis 145, and possibly in other lactic acid bacteria.

The Knockout of the ASIP Gene Altered the Lipid Composition in Bovine Mammary Epithelial Cells via the Expression of Genes in the Lipid Metabolism Pathway.

Simple SummaryAccording to the FDA, a litre of milk contains about 33 g of total lipids, 95% of which are triacylglycerols made up of varying lengths and saturation of fatty acids. The increase in free fatty acids in milk may lead to changes in the flavour of milk and milk products. Bovine mammary epithelial cells (bMECs) function to synthesize and secrete milk and are good in vitro models for cells in milk quality research. In this research, we report for the first time the effect of the ASIP gene knockout in bovine mammary epithelial cells using CRISPR/Cas9 technology. We found that ASIP knockout could down-regulate the expression of PPARγ, FASN, and SCD, thus affecting the saturation of fatty acids in milk and upregulating the expression of FABP4, ELOVL6, and ACSL1, increasing the synthesis of medium-long chain fatty acids. These results may allow the selection of potential targets in future molecular breeding efforts for dairy cows.Agouti signalling protein (ASIP) is a coat colour-related protein and also is a protein-related to lipid metabolism, which had first been found in agoutis. According to our previous study, ASIP is a candidate gene that affects the lipid metabolism in bovine adipocytes. However, its effect on milk lipid has not been reported yet. This study focused on the effect of the ASIP gene on the lipid metabolism of mammary epithelial cells in cattle. The ASIP gene was knocked out in bMECs by using CRISPR/Cas9 technology. The result of transcriptome sequencing showed that the differentially expressed genes associated with lipid metabolism were mainly enriched in the fatty acids metabolism pathways. Furthermore, the contents of intracellular triglycerides were significantly increased (p < 0.05), and cholesterol tended to rise (p > 0.05) in bMECs with the knockout of the ASIP gene. Fatty acid assays showed a significant alteration in medium and long-chain fatty acid content. Saturated and polyunsaturated fatty acids were significantly up-regulated (p < 0.05), and monounsaturated fatty acids were significantly decreased in the ASIP knockout bMECs (p < 0.05). The Q-PCR analysis showed that knockout of ASIP resulted in a significant reduction of gene expressions like PPARγ, FASN, SCD, and a significant up-regulation of genes like FABP4, ELOVL6, ACSL1, HACD4 prompted increased mid-to long-chain fatty acid synthesis. Overall, ASIP plays a pivotal role in regulating lipid metabolism in bMECs, which could further influence the component of lipid in milk.

A Novel Cell Death Mechanism Involving the Sphingosine‐to‐Glycerophospholipid Pathway

Apoptosis is the most well‐studied form of cell death, but there exist other cell death pathways that also have roles in normal physiology and disease. It is unclear what other forms of cell death remain to be discovered and how these pathways could inform our understanding of cell and molecular biology. Caspase‐independent lethal 56 (CIL56) is a compound that kills cells via a novel cell death mechanism. We conducted a genome‐wide CRISPR screen to identify novel regulators of this death pathway. From the screen, we identified trans‐2‐enoyl‐CoA reductase (TECR) as a key regulator of CIL56‐induced death. TECR is localized to the endoplasmic reticulum and is required for very long‐chain fatty acid (VLCFA) synthesis. When the gene encoding TECR is disrupted, cells become resistant to CIL56‐induced death. We find that VLCFA synthesis is dispensable for CIL56‐induced death. On the contrary, TECR has a non‐canonical role in the conversion of sphingosine to palmitate in the sphingosine‐to‐glycerophospholipid pathway. Through chemical complementation analyses, we find that this pathway is important for death induction by CIL56. It remains unclear how this pathway could be acting to execute cell death. It is known that palmitate produced in the endoplasmic reticulum can be incorporated into ceramide species, which have long been associated with cell death. Preliminary lipidomic analyses reveal a dramatic increase in palmitoyl‐ceramide upon CIL56 treatment. We are investigating the role of this species in CIL56‐induced cell death to further characterize the mechanism of death and its importance.

Δ5 and Δ6 desaturase indices are not associated with zinc intake as determined by dietary assessment or modified by a zinc-FADS1 rs174547 SNP interaction in young Canadian adults

BackgroundZinc is an essential trace mineral that serves as a cofactor for the delta-5 and delta-6 desaturases (D5D, D6D) that are critical for long-chain polyunsaturated fatty acid (LC-PUFA) synthesis. While plasma zinc levels are generally reported to be associated with D5D and D6D indices in humans, it remains unclear if dietary zinc intake can be similarly associated with desaturase indices. Therefore, the present investigation examined if zinc intake determined by food frequency questionnaire (FFQ) is associated with desaturase indices in young Canadian adults. Additionally, we explored whether desaturase indices were modified by an interaction between dietary zinc intake and a common variant in the FADS1 gene. MethodsDietary zinc intake (FFQ), plasma fatty acids (gas chromatography) and the FADS1 rs174547 polymorphism were analyzed in young men and women (n = 803) from the cross-sectional Toronto Nutrigenomics and Health Study. Product-to-precursor fatty acid ratios were used to determine desaturase enzyme indices (D5D = 20:4n-6/20:3n-6; D6D = 18:3n-6/18:2n-6). Individuals were grouped according to dietary zinc intake, as well as by their rs174547 genotype (TT vs. TC+CC). Data were analyzed by 1-way and 2-way ANCOVA. ResultsPlasma fatty acids and D5D/D6D indices did not differ between individuals grouped according to dietary zinc intake. Further, the recently proposed biomarker of zinc intake, 20:3n-6/18:2n-6, was not associated with dietary zinc intake. Although the FADS1 rs174547 SNP was significantly associated with D5D and D6D indices in both men and women (p < 0.0001), we did not find evidence of a dietary zinc intake – FADS1 SNP interaction on D5D or D6D indices. ConclusionDietary zinc intake, as determined using FFQs, does not predict differences in desaturase indices, irrespective of FADS1 genotype.

Inhibition of Δ-6 desaturase reduces fatty acid re-esterification in 3T3-L1 adipocytes independent of changes in n3-PUFA cellular content

Δ-6 desaturase (D6D) is a key enzyme in the synthesis of long-chain polyunsaturated fatty acids (LC-PUFA). Evidence suggests that reduced D6D activity not only disrupts LC-PUFA production, but also impacts whole body lipid handling and body weight; however, the mechanisms remain largely unexplored. Therefore, we investigated the effect of D6D inhibition on the regulation of lipid accumulation in 3T3-L1 adipocytes with and without changes in n-3 PUFA content. 3T3-L1 cells were treated with a D6D inhibitor (SC-26196) in the presence or absence of α-linolenic acid (ALA) throughout differentiation. We found that D6D inhibition blocked the conversion of ALA to eicosapentaenoic acid (EPA) and docosapentaenoic acid (DPAn-3) when ALA was supplemented, while no changes in n-3 PUFA content were observed in cells treated with the D6D inhibitor alone. D6D inhibited cells had reduced triacylglycerol (TAG) accumulation despite an EPA/DPA deficiency. In addition, analyses of cellular protein markers, as well as non-esterified fatty acids and glycerol release in medium, suggested an increase in lipolysis and a decrease in fatty acid re-esterification in D6D-inhibited cells, independent of n-3 PUFA changes. To provide further evidence, we treated cells with the D6D inhibitor in the presence or absence of EPA and compared them with ALA-treated cells. Although EPA further reduced TAG content, the reduced markers of fatty acid re-esterification were not affected by ALA or EPA. Collectively, this study provides new insight showing that D6D inhibition reduces TAG accumulation and fatty acid re-esterification in adipocytes independent of changes in n-3 PUFA cellular content.

Halogenated bisphenol a analogues induce PPARγ-independent toxicity within human hepatocellular carcinoma cells

Tetrabromobisphenol A (TBBPA) and tetrachlorobisphenol A (TCBPA) – both halogenated bisphenol (BPA) analogues – are suspected ligands of peroxisome proliferator-activated receptor gamma (PPARγ). While previous studies have shown that TBBPA and TCBPA activate PPARγ within cell-free assays, the downstream effects of TBBPA- and TCBPA-induced PPARγ activation on cellular transcription and physiology have not been thoroughly investigated. Therefore, the objective of this study was to determine whether exposure to TBBPA or TCBPA (either alone or in combination) alters levels of neutral lipids and fatty acid synthase (FASN) – an enzyme that catalyzes synthesis of long-chain saturated fatty acids – within intact cells in a PPARγ-dependent manner. For this study, we relied on human hepatocellular carcinoma (HepG2) cells as a model since these liver cells express basal levels of PPARγ and have been used to study lipoprotein metabolism and regulation of drug metabolizing enzymes. Although exposure to TBBPA and TCBPA alone did not affect cell viability nor neutral lipid and FASN levels in a concentration-dependent manner, exposure to binary mixtures of TBBPA and TCBPA resulted in a concentration-dependent decrease in cell viability in the absence of concentration-dependent effects on neutral lipid and FASN levels. Interestingly, exposure to TBBPA or TCBPA alone or as a mixture enhanced the effects of a reference PPARγ agonist (ciglitazone) and antagonist (GW 9662) on cell viability (but not neutral lipid levels), suggesting that these two halogenated BPA analogues may interact synergistically with ciglitazone and GW 9662 to induce cytotoxicity. However, overexpression of PPARγ did not mitigate nor enhance the effects of TBBPA – a potent PPARγ ligand predicted by ToxCast’s cell-free competitive binding assays – on cell viability, neutral lipid levels, nor the cellular transcriptome. Overall, our findings suggest that halogenated BPA analogues such as TCBPA and TBBPA induce toxicity within HepG2 cells in a PPARγ-independent manner.

Bile Acids, Gut Microbiome and the Road to Fatty Liver Disease.

This article describes the complex interactions occurring between diet, the gut microbiome, and bile acids in the etiology of fatty liver disease. Perhaps 25% of the world's population may have nonalcoholic fatty liver disease (NAFLD) and a significant percentage (∼20%) of these individuals will progress to nonalcoholic steatohepatitis (NASH). Currently, the only recommended treatment for NAFLD and NASH is a change in diet and exercise. A Western-type diet containing high fructose corn syrup, fats, and cholesterol creates gut dysbiosis, increases intestinal permeability and uptake of LPS causing low-grade chronic inflammation in the body. Fructose is a "lipogenic" sugar that induces long-chain fatty acid (LCFA) synthesis in the liver. Inflammation decreases the oxidation of LCFA, allowing fat accumulation in hepatocytes. Hepatic bile acid transporters are downregulated by inflammation slowing their enterohepatic circulation and allowing conjugated bile acids (CBA) to increase in the serum and liver of NASH patients. High levels of CBA in the liver are hypothesized to activate sphingosine-1-phosphate receptor 2 (S1PR2), activating pro-inflammatory and fibrosis pathways enhancing NASH progression. Because inflammation appears to be a major physiological driving force in NAFLD/NASH, new drugs and treatment protocols may require the use of anti-inflammatory compounds, such as berberine, in combination with bile acid receptor agonists or antagonists. Emerging new molecular technologies may provide guidance in unraveling the complex physiological pathways driving fatty liver disease and better approaches to prevention and treatment. © 2021 American Physiological Society. Compr Physiol 11:1-12, 2021.

Association analysis between FASN genotype and milk traits in Mediterranean buffalo and its expression among different buffalo tissues

Fatty acid synthase (FASN) is a multifunctional protein that catalyzes the synthesis of long-chain saturated fatty acid. In this study, we identified the single nucleotide polymorphisms (SNPs), and their association with milk traits in Mediterranean buffalo, and the expression of FASN gene in different tissues was measured. Nine SNPs (g.-1640G > A, g.-1099C > T, g.1095C > A, g.3221G > A, g.4762G > A, g.5299G > A, g.7164G > A, g.7272T > C, and g.8927T > C) were identified by DNA pooled sequencing and then genotyped. Seven identified SNPs except g.3221G > A and g.8927T > C were found significantly associated with both fat and protein percentage, and also the g.7164G > A and g.8927T > C had significant association with peak milk yield and protein percentage, respectively. One haplotype block was successfully constructed by linkage disequilibrium (LD) analysis and it showed a significant association with both fat percentage and protein percentage. Expression of FASN gene was found in almost all the buffalo tissues including mammary gland, heart, liver, spleen, lung, kidney, uterus, and ovary, and to be highest in lung and mammary gland. Our findings suggest that polymorphisms in the buffalo FASN gene are associated with milk production traits and can be used as a candidate gene for milk traits and marker-assisted selection in buffalo breeding program.

Reduction of litter size during lactation in rats greatly influences fatty acid profiles in dams.

This study aimed to determine in lactating rats how fatty acid profiles are affected by litter size. On day 2 after parturition, litters of lactating rats were adjusted to a normal litter size of 9 pups/dam (NL) or to a small litter of 4 pups/dam (SL), and dams were studied at day 21 of lactation. Plasma glucose, insulin, and docosahexaenoic acid (DHA) concentrations were higher in SL than in NL dams, whereas the concentrations of most other fatty acids, triacylglycerols (TAG), and non-esterified fatty acids were lower in the SL dams. In the liver, the concentration of TAG was lower in SL than in NL dams as was the concentration of most fatty acids, with the exception of stearic acid (STA), arachidonic acid (ARA), and DHA concentrations that were higher in SL. Both plasma and liver Δ9 desaturase indices were lower in SL than in NL dams, whereas both Δ5 and Δ6 desaturase indices were higher in SL dams. In the liver, the expression of acetyl CoA carboxylase was lower in SL than in NL dams, and among the different adipose tissue depots, only mesenteric adipose tissue showed a higher concentration of most fatty acids in SL than in NL dams. It is proposed that reduction of litter size during lactation decreases liver lipogenesis de novo, although the synthesis of long-chain polyunsaturated fatty acids from their corresponding precursors increases, and lipolytic activity in mesenteric adipose tissue decreases probably as result of increased insulin responsiveness.