18-carbon Fatty Acids Research Articles

Improvement of the growth performance, intestinal health, and water quality in juvenile crucian carp (Carassius auratus gibelio) biofortified system with the bacteria-microalgae association

Aquaculture, as one of the largest food production sectors, is a candidate industry to solve the worldwide food shortage. Nitrogenous compounds from uneaten feed and excretion continually destroy the rearing water quality during the breeding which causes slow growth, production reduction, and even death. Thus, alleviating water contamination can improve fish welfare and prevent disease occurrence. In the present study, a stable bacteria-microalgae association was used to construct a biofortified crucian carps culture system without water exchange. During the 8-week experiments, the water quality, fish production, and intestinal health were assessed. In this biofortified system, water quality was significantly improved and the content of total ammonia-N and nitrite-N was finally in a state of dynamic equilibrium at a lower concentration compared with that in blank control. The final body weight of crucian carps in the bacteria-microalgae groups was significantly improved by 10.52%. The crucian carps intestinal health including amylase and lipase activities, villus length and width, and muscle thickness was also significantly increased by 56.33%, 63.89%, 347.25%, 98.48%, and 129.53%, respectively, in bacteria-microalgae groups. Intestinal microbiota was improved significantly by changing the microbiota composition and LEfSe analysis demonstrated that some genera frequently found in the intestines of stressed and dying animals were enriched in crucian carps intestine in blank control. The KEGG prediction proved that metabolisms including carbon metabolism, pyruvate metabolism, and fatty acid metabolism were significantly improved. In summary, the bacteria-microalgae association biofortified culture system improved the rearing water quality, and then improved the intestinal health of crucian carp, eventually increased the production of crucian carp.

Fatty acid ecological tracers highlight the role of diet in perfluoroalkyl acid contaminant exposure in eggs of an omnivorous bird

Herring gulls (Larus argentatus) are generalist feeders; contaminant levels in their eggs reflect chemical exposure and uptake due to foraging in both aquatic and terrestrial environments. Hence, contaminant levels in their eggs provide insights into sources and relative importance of aquatic versus terrestrial pathways of chemical transfer. Here, perfluoroalkyl acids (PFAAs) known to be bioaccumulative were measured in individual herring gull eggs from one site on Lake Superior, Ontario, Canada. Thirteen perfluorinated carboxylates (PFCA, C4-C18) and four perfluorinated sulfonates (PFSA, C4-C10) were measured. Total PFCA and total PFSA concentrations varied 4- and 5-fold, respectively, among eggs. To understand these differences, stable carbon and nitrogen isotopes and fatty acid dietary tracers were measured in the same eggs. Stable isotopes were not useful in explaining inter-egg differences in PFAA concentrations. However, a variety of omega 3 (n-3) and omega 6 (n-6) fatty acid measures were correlated with C9-C13 PFCAs as well as the PFSAs: perfluoro-1-hexanesulfonic acid (PFHxS) and perfluoro-1-octanesulfonic acid (PFOS). In general, n-3 fatty acids were positively correlated with egg PFAA concentrations while only the n-6 fatty acids exhibited negative relationships with egg PFAA levels. Proportions of n-3 and n-6 fatty acids in eggs would be expected to increase and decrease, respectively, with increased aquatic food in the gull diet. Results indicate that increased use of aquatic food led to heightened PFAA exposure in these generalist consumers sampled in a relatively remote area. They also highlight the utility of employing a variety of dietary markers for understanding contaminant exposure and accumulation.

Olive- and Coconut-Oil-Enriched Diets Decreased Secondary Bile Acids and Regulated Metabolic and Transcriptomic Markers of Brain Injury in the Frontal Cortexes of NAFLD Pigs.

The objective of this study was to investigate the effect of dietary fatty acid (FA) saturation and carbon chain length on brain bile acid (BA) metabolism and neuronal number in a pig model of pediatric NAFLD. Thirty 20-day-old Iberian pigs, pair-housed in pens, were randomly assigned to receive one of three hypercaloric diets for 10 weeks: (1) lard-enriched (LAR; n = 5 pens), (2) olive-oil-enriched (OLI, n = 5), and (3) coconut-oil-enriched (COC; n = 5). Pig behavior and activity were analyzed throughout the study. All animals were euthanized on week 10 and frontal cortex (FC) samples were collected for immunohistochemistry, metabolomic, and transcriptomic analyses. Data were analyzed by multivariate and univariate statistics. No differences were observed in relative brain weight, neuronal number, or cognitive functioning between diets. Pig activity and FC levels of neuroprotective secondary BAs and betaine decreased in the COC and OLI groups compared with LAR, and paralleled the severity of NAFLD. In addition, OLI-fed pigs showed downregulation of genes involved in neurotransmission, synaptic transmission, and nervous tissue development. Similarly, COC-fed pigs showed upregulation of neurogenesis and myelin repair genes, which caused the accumulation of medium-chain acylcarnitines in brain tissue. In conclusion, our results indicate that secondary BA levels in the FCs of NAFLD pigs are affected by dietary FA composition and are associated with metabolic and transcriptomic markers of brain injury. Dietary interventions that aim to replace saturated FAs by medium-chain or monounsaturated FAs in high-fat hypercaloric diets may have a negative effect on brain health in NAFLD patients.

Serum ω-3 Fatty Acids and Cognitive Domains in Community-Dwelling Older Adults from the NuAge Study: Exploring the Associations with Other Fatty Acids and Sex

BackgroundOmega-3 (n–3) PUFAs are suggested to play a role in the prevention of cognitive decline. The evidence may be inconsistent due to methodologic issues, including interrelations with other long-chain (14 or more carbons) fatty acids (LCFAs) and use of sex as a confounding factor rather than an effect modifier ObjectivesThis study evaluated the association between serum n–3 PUFAs and performance across 4 cognitive domains, overall and by sex, while controlling for other LCFAs MethodsIn total, 386 healthy older adults (aged 77.4 ± 3.8 y; 53% females) from the Quebec Longitudinal Study on Nutrition and Successful Aging underwent a cognitive evaluation and blood sampling. Verbal and nonverbal episodic memory, executive functioning, and processing speed were evaluated. Serum LCFA concentrations were measured by gas chromatography. LCFAs were grouped according to standard fatty acid classes and factor analysis using principal component analysis (FA-PCA). Multivariate linear regression models were performed, including unadjusted and adjusted models for other LCFAs ResultsHigher n–3 PUFA concentrations were associated with better nonverbal memory and processing speed in fully adjusted models not including other LCFAs (βs of 0.21 and 0.19, respectively). The magnitude of these associations varied when other LCFAs were entered in the model (βs of 0.27 and 0.32, respectively) or when FA-PCA factors were considered (βs of 0.27 and 0.21, respectively). Associations with verbal episodic memory were limited to higher concentrations of EPA, whereas there was no association between n–3 PUFAs and executive functioning. Higher n–3 PUFAs were associated with better verbal and nonverbal episodic memory in females and with better executive functioning and processing speed in males ConclusionsThese results suggest that other LCFAs should be considered when evaluating the association between n–3 PUFAs and cognitive performance in healthy older adults. Sex differences across cognitive domains warrant further investigation. J Nutr 2022;152:2117–2124.

Impact of Nanolayered Material and Nanohybrid Modifications on Their Potential Antibacterial Activity.

Due to an escalating increase in multiple antibiotic resistance among bacteria, novel nanomaterials with antimicrobial properties are being developed to prevent infectious diseases caused by bacteria that are common in wastewater and the environment. A series of nanolayered structures and nanohybrids were prepared and modified by several methods including an ultrasonic technique, intercalation reactions of fatty acids, and carbon nanotubes, in addition to creating new phases based on zinc and aluminum. The nanomaterials prepared were used against a group of microorganisms, including E. coli, S. aureus, Klebsiella pneumoniae and Pseudomonas aeruginosa. Experimental results revealed that a nanohybrid based on carbon nanotubes and fatty acids showed significant antimicrobial activity against E. coli, and can be implemented in wastewater treatment. Similar behavior was observed for a nanolayered structure which was prepared using ultrasonic waves. For the other microorganisms, a nanolayered structure combined with carbon nanotubes showed a significant and clear inhibitory effect on S. aureus, Klebsiella pneumoniae and Pseudomonas aeruginosa. It is concluded that the nanolayered structures and nanohybrids, which can be modified at low cost with high productivity, using simple operations and straightforward to use equipment, can be considered good candidates for preventing infectious disease and inhibiting the spread of bacteria, especially those that are commonly found in wastewater and the environment.

Physiological and Differential Proteomic Analysis at Seedling Stage by Induction of Heavy-Ion Beam Radiation in Wheat Seeds.

Novel genetic variations can be obtained by inducing mutations in the plant which help to achieve novel traits. The useful mutant can be obtained through radiation mutation in a short period which can be used as a new material to produce new varieties with high yield and good quality wheat. In this paper, the proteomic analysis of wheat treated with different doses of 12C and 7Li ion beam radiation at the seedling stage was carried out through a Tandem Mass Tag (TMT) tagging quantitative proteomic analysis platform based on high-resolution liquid chromatography-mass spectrometry, and the traditional 60Co-γ-ray radiation treatment for reference. A total of 4,764 up-regulated and 5,542 down-regulated differentially expressed proteins were identified. These proteins were mainly enriched in the KEGG pathway associated with amino acid metabolism, fatty acid metabolism, carbon metabolism, photosynthesis, signal transduction, protein synthesis, and DNA replication. Functional analysis of the differentially expressed proteins showed that the oxidative defense system in the plant defense system was fully involved in the defense response after 12C ion beam and 7Li ion beam radiation treatments. Photosynthesis and photorespiration were inhibited after 12C ion beam and 60Co-γ-ray irradiation treatments, while there was no effect on the plant with 7Li ion beam treatment. In addition, the synthesis of biomolecules such as proteins, as well as multiple signal transduction pathways also respond to radiations. Some selected differentially expressed proteins were verified by Parallel Reaction Monitoring (PRM) and qPCR, and the experimental results were consistent with the quantitative results of TMT. The present study shows that the physiological effect of 12C ion beam radiation treatment is different as compared to the 7Li ion beam, but its similar to the 60Co-γ ray depicting a significant effect on the plant by using the same dose. The results of this study will provide a theoretical basis for the application of 12C and 7Li ion beam radiation in the mutation breeding of wheat and other major crops and promote the development of heavy ion beam radiation mutation breeding technology.

Structural and in vitro starch digestion properties of starch-fatty acid nanocomplexes: effect of chain lengths and degree of unsaturation of fatty acids.

The structural and digestion properties of starch-lipid complexes are closely related to the properties of lipids. The chain length and degree of unsaturation of fatty acids (FAs), which can affect the structural and digestion properties of starch-lipid nanocomplexes, therefore need to be examined in detail to gain a better understanding of this. In this study, the effects of chain length (10-18 carbons) and degree of unsaturation (0-2) of FA on the structural and in vitro starch digestion properties of high amylose corn starch (HAS)-FA nanocomplexes were investigated, as was the correlation between their structural alterations and digestibility. This study showed that HAS-FA nanocomplexes with 10-carbon (38.55%) and 12-carbon (44.56%) FAs displayed high-resistant starch (RS)and slowly digestible starch (SDS) content, whereas those with 18-carbon FAs with two double bonds exhibited low RS + SDS content (23.41%). The complexing index, R1047/1022 , relative crystallinity, and enthalpy change in the HAS-FA nanocomplexes also increased with the reduction in the chain length (except for 10-carbon FA) and the degree of unsaturation of FAs, whereas the equilibrium hydrolysis percentage, kinetic constant and apparent amylose content showed an opposite trend. Chain length and degree of unsaturation of FAs affected the digestibility of HAS-FA nanocomplexes. The HAS-FA nanocomplexes with 12-carbon FAs displayed high RS + SDS content with higher degrees of molecular order at long-range and short-range levels. Results provided guidelines to regulate the digestibility of starch-fatty acid nanocomplexes by varying the FA structures. © 2022 Society of Chemical Industry.

Identification and Characterization of a Novel Species of Genus Akkermansia with Metabolic Health Effects in a Diet-Induced Obesity Mouse Model

Akkermansia muciniphila is a well-known bacterium with the ability to degrade mucin. This metabolic capability is believed to play an important role in the colonization of this bacterium in the gut. In this study, we report the identification and characterization of a novel Akkermansia sp. DSM 33459 isolated from human feces of a healthy donor. Phylogenetic analysis based on the genome-wide average nucleotide identity indicated that the Akkermansia sp. DSM 33459 has only 87.5% similarity with the type strain A. muciniphila ATCC BAA-835. Akkermansia sp. DSM 33459 showed significant differences in its fatty acid profile and carbon utilization as compared to the type strain. The Akkermansia sp. DSM 33459 strain was tested in a preclinical obesity model to determine its effect on metabolic markers. Akkermansia sp. DSM 33459 showed significant improvement in body weight, total fat weight, and resistin and insulin levels. Interestingly, these effects were more pronounced with the live form as compared to a pasteurized form of the strain. The strain showed production of agmatine, suggesting a potential novel mechanism for supporting metabolic and cognitive health. Based on its phenotypic features and phylogenetic position, it is proposed that this isolate represents a novel species in the genus Akkermansia and a promising therapeutic candidate for the management of metabolic diseases.

Metabolic Dysregulation in Acute SARS-CoV-2 Infection

The global pandemic of coronavirus disease 2019 (COVID-19) caused by the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), mostly presented with mild to moderate or no symptoms and patients having pre-existing metabolic disorders like diabetes, cardiovascular diseases, and obesity are at risk for severe and critical cases of infection. The metabolic landscape of COVID-19 and its association with disease severity has urged the need to understand how metabolic reprogramming occurs during the acute SARS-CoV-2 infection with the ultimate goal toward therapeutic intervention. Viral replication is dependent on extracellular carbon sources such as glucose and glutamine and induces metabolic alterations in host cell including host central carbon metabolism, nucleotide, fatty acids, and lipid synthesis that modulate viral pathogenesis and host response. SARSCoV-2 dysregulation of PI3K/Akt/mTOR and hypoxia-inducible factor 1 (HIF-1) signaling pathways in infected cells and affect mitochondrial functions. These pathways regulate glycolysis by altering glucose transporters (GLUTs) across cell membranes. The altered extracellular glucose, mannose, and glutamate levels could be due to dysregulated carbohydrate metabolism and mitochondrial function. Host cellular response following SARSCoV-2 infection identified a strong acute metabolic adaptation in the lung epithelial cells (Calu-3) by modulating central carbon metabolism and indicative of mitochondrial dysfunction that is also observed in severe COVID-19 patients. Glycolysis and glutaminolysis can be essential for virus replication, and hostbased metabolic strategies to inhibit viruses to weaken the viral replication by metabolic intervention could be an attractive antiviral therapy. Targeting these pathways with inhibitors such as MK2206 (Akt inhibitor) or 2-deoxy-D-glucose (2-DG; glycolysis inhibitor) can lower the viral burden in the cells in vitro.

Production and Characterization of Rhamnolipids Produced by Pseudomonas aeruginosa DBM 3774: Response Surface Methodology Approach.

Rhamnolipids are extensively studied biosurfactants due to their potential in many industrial applications, eco-friendly production and properties. However, their availability for broader application is severely limited by their production costs, therefore the optimization of efficacy of their cultivation gains significance as well as the information regarding the physio-chemical properties of rhamnolipids resulting from various cultivation strategies. In this work, the bioprocess design focused on optimization of the rhamnolipid yield of Pseudomonas aeruginosa DBM 3774 utilizing the response surface methodology (RSM). Six carbon sources were investigated for their effect on the rhamnolipid production. The RSM prediction improved the total rhamnolipid yield from 2.2 to 13.5 g/L and the rhamnolipid productivity from 11.6 to 45.3 mg/L/h. A significant effect of the carbon source type, concentration and the C/N ratio on the composition of the rhamnolipid congeners has been demonstrated for cultivation of P. aeruginosa DBM 3774 in batch cultivation. Especially, changes in presence of saturated fatty acid in the rhamnolipid congeners, ranging from 18.8% of unsaturated fatty acids (carbon source glycerol; 40 g/L) to 0% (sodium citrate 20 g/L) were observed. This demonstrates possibilities of model based systems as basis in cultivation of industrially important compounds like biosurfactants rhamnolipids and the importance of detailed study of interconnection between cultivation conditions and rhamnolipid mixture composition and properties.

Positive Regulation of the Antiviral Activity of Interferon-Induced Transmembrane Protein 3 by S-Palmitoylation.

The interferon-induced transmembrane protein 3 (IFITM3), a small molecule transmembrane protein induced by interferon, is generally conserved in vertebrates, which can inhibit infection by a diverse range of pathogenic viruses such as influenza virus. However, the precise antiviral mechanisms of IFITM3 remain unclear. At least four post-translational modifications (PTMs) were found to modulate the antiviral effect of IFITM3. These include positive regulation provided by S-palmitoylation of cysteine and negative regulation provided by lysine ubiquitination, lysine methylation, and tyrosine phosphorylation. IFITM3 S-palmitoylation is an enzymatic addition of a 16-carbon fatty acid on the three cysteine residues within or adjacent to its two hydrophobic domains at positions 71, 72, and 105, that is essential for its proper targeting, stability, and function. As S-palmitoylation is the only PTM known to enhance the antiviral activity of IFITM3, enzymes that add this modification may play important roles in IFN-induced immune responses. This study mainly reviews the research progresses on the antiviral mechanism of IFITM3, the regulation mechanism of S-palmitoylation modification on its subcellular localization, stability, and function, and the enzymes that mediate the S-palmitoylation modification of IFITM3, which may help elucidate the mechanism by which this IFN effector restrict virus replication and thus aid in the design of therapeutics targeted at pathogenic viruses.

A high-resolution time series of particulate matter fatty acids reveals temporal dynamics of the composition and quality available to zooplankton in a temperate coastal ocean

Particulate organic matter (POM) forms the base of the pelagic food web, but is a complex category of material that undergoes substantial changes in quantity and quality across different time scales. As the primary consumers of POM, zooplankton are influenced by these fluctuations, resulting in shifts in the food web pathways that contribute to the production of higher trophic levels. We measured POM fatty acids, which are critical nutritional components in marine food webs, along with a suite of associated biotic and abiotic environmental conditions at a temperate coastal site over four years. Using these data, we investigated the co-occurring patterns of prey quality, quantity, and size, to develop a holistic understanding of how the prey field for zooplankton varies over the seasonal cycle and inter-annually. The seasonal pattern of POM fatty acids corresponded to the succession of phytoplankton taxa, but displayed stronger relationships to size-fractionated Chl a than taxonomic observations. Times with high micro-Chl biomass (spring and fall blooms) had the greatest concentrations of high quality food, but fatty acid levels remained high throughout the summer when Chl a concentrations dropped and the size distribution shifted towards pico-Chl. The 18-carbon polyunsaturated fatty acids 18:3ω3 (α-linolenic acid) and 18:4ω3 (stearidonic acid) increased during this time and were correlated with pico-Chl. In addition, the important nutritional factor for zooplankton and fish, the fatty acid ratio DHA:EPA (22:6ω3/20:5ω3), peaked during the middle of summer separately from the peak in Chl a. These seasonal patterns resulted in tradeoffs among the abundance, size, and nutritional quality of prey for zooplankton. We validated the basal sources of several fatty acids used as trophic markers within food web studies and in particular note their power for resolving size-based trophic connections. Interannual variability, e.g., the occurrence of fall diatom blooms and the timing of community shifts, is also discussed. This work lays the foundation for future studies of the zooplankton community at this location and the incorporation of realistic prey conditions into zooplankton studies.

Comparing among second, third, and fourth generations (genetically modified) of biodiesel feedstocks from the perspective of engine, exhaust gasses and fatty acid: Comparative assessment

Three new types of biodiesel are examined in this report, including the second, third, and fourth generations. Various factors (oxygen to carbon (O/C), hydrogen to carbon (H/C), carbon-chain lengths (CCLs), saturated and unsaturated fatty acids) have been investigated on engine performance, exhaust gasses, and combustion. Three new types of oil, second (Taxus baccata), third (algae Ulothrix) generation), and fourth (Mentha pulegium) generation (genetically modified) were implemented. The effect of CCLs on viscosity and heating values (HV) proved the promotion of CCLs enhances HV and viscosity; the third generation obtained the highest torque and power compared to the other two generations. Results demonstrated that the advance of the viscosity and diminish of the HV triggers the increase of BSFC and the lowest BSFC presented by the third generation. Regarding outcomes, the rise of unsaturation acids and reduction of CCLs can decline the CN, so the maximum EGT presented by the fourth generation of biodiesel is in contrast with the third generation. The extended CCLs and the lowermost O/C influenced CO and HC, which third-generation showed a minimum. The influence of fatty acids on CN and NOx was displayed, and the third generation gained the lowest NOx. The fourth generation exhibited excessive soot, and the third generation showed the lowest soot. The third-generation biodiesel had the lowest peak pressure compared to other samples. The fourth generation is still less efficient than the third generation, which can be proved that this generation has better results.

Effect of type of fatty acid attached to chitosan on walnut oil-in-water Pickering emulsion properties

The effect of fatty acid type bonded to chitosan on the emulsifying properties of chitosan-based particles was investigated. Capric acid, myristic acid, and stearic acid were attached to chitosan chains. Longer fatty acids in the structure of chitosan lead to the better and more uniform formation of chitosan nanogels. The contact angle of chitosan, chitosan-capric acid, chitosan-myristic acid and chitosan-stearic acid were found to be 52.5°, 60.0°, 65.1° and 72.5°, respectively. Different chitosan nanogels were used to stabilize walnut oil emulsions, and the emulsion stabilized with chitosan-stearic acid nanogels had the lowest creaming index (15.2%). Stabilized emulsions with chitosans attached to longer chain acids were more adapted to the mechanism of Pickering emulsions, in addition to having higher viscosity as well as more gel-like behavior. In general, this study showed that emulsifying properties of chitosan could be improved by increasing the number of fatty acid carbons bonded to chitosan.

Regulation of Δ6Fads2 Gene Involved in LC-PUFA Biosynthesis Subjected to Fatty Acid in Large Yellow Croaker (Larimichthys crocea) and Rainbow Trout (Oncorhynchus mykiss).

Δ6 fatty acyl desaturase (Δ6Fads2) is regarded as the first rate-limiting desaturase that catalyzes the biosynthesis of long-chain polyunsaturated fatty acids (LC-PUFA) from 18-carbon fatty acid in vertebrates, but the underlying regulatory mechanism of fads2 has not been comprehensively understood. This study aimed to investigate the regulation role of fads2 subjected to fatty acid in large yellow croaker and rainbow trout. In vivo, large yellow croaker and rainbow trout were fed a fish oil (FO) diet, a soybean oil (SO) diet or a linseed oil (LO) diet for 10 weeks. The results show that LO and SO can significantly increase fads2 expression (p < 0.05). In vitro experiments were conducted in HEK293T cells or primary hepatocytes to determine the transcriptional regulation of fads2. The results show that CCAAT/enhancer-binding protein α (C/EBPα) can up-regulate fads2 expression. GATA binding protein 3 (GATA3) can up-regulate fads2 expression in rainbow trout but showed opposite effect in large yellow croaker. Furthermore, C/EBPα protein levels were significantly increased by LO and SO (p < 0.05), gata3 expression was increased in rainbow trout by LO but decreased in large yellow croaker by LO and SO. In conclusion, we revealed that FO replaced by LO and SO increased fads2 expression through a C/EBPα and GATA3 dependent mechanism in large yellow croaker and rainbow trout. This study might provide critical insights into the regulatory mechanisms of fads2 expression and LC-PUFA biosynthesis.

Influence of different kinds of fatty acids on the behavior, structure and digestibility of high amylose maize starch-fatty acid complexes.

The formation of starch-lipid complexes is of interest to food processing and human nutrition. Fatty acid (FA) structure is important for the formation and structure of starch-FA complexes. However, there is limited research regarding the complexing behavior between amylose and different kinds of FAs, as well as the relationship between fine structures and digestibility of the formed complexes. This study aimed to investigate the behavior, fine structure, and digestibility of complexes formed between high amylose maize starch (HMS) and FA having various chain lengths and unsaturation degrees. Complexes containing different FA structures showed V6III -type crystals. Complexes containing 18-carbon unsaturated FAs displayed significantly higher complexing index (P < 0.05) than other complexes. Complexes containing 12-carbon FAs and 18-carbon FAs with one unsaturation degree showed a higher degree of structural order and resistant starch (RS) content than other complexes. The 12-carbon FAs exhibited a higher binding degree with helical cavity of amylose than other FAs. Additionally, 10-carbon and 18-carbon saturated FAs tended to combine with HMS outside amylose helices more than other FAs. Laser confocal micro-Raman imaging revealed that the physically embedded 10-carbon and 18-carbon saturated FAs showed heterogeneous distribution in complexes, and that the complexed 18-carbon FAs with one unsaturation degree exhibited homogeneous distribution. The behavior, structural order and digestibility of complexes could be regulated by FA structure. The 12-carbon FAs and 18-carbon FAs with one unsaturation degree were more suitable for the production of HMS-FA complexes with higher structural order and RS content than other FAs. © 2022 Society of Chemical Industry.

Dietary 18-carbon fatty acid unsaturation improves the muscle fiber development and meat quality of Megalobrama amblycephala

The study aimed to investigate the effects of four fatty acids with the same carbon-chain length and different saturations, stearic acid (SA), oleic acid (OA), linoleic acid (LA), and linolenic acid (LNA), on the growth performance and muscle quality of Megalobrama amblycephala through in vivo and in vitro experiments. A total of 320 fish with similar initial weight (34.97 ± 0.14 g) were randomly fed 3% four kinds of 18-carbon fatty acids with different carbon saturation. Growth performance was assessed at the end of the feeding trial, and samples were collected for the corresponding indicators. Results showed that the weight gain rate (WGR) and specific growth rate (SGR) of unsaturated fatty acids groups were significantly increased (P < 0.05) than the SA group. Meanwhile, unsaturated fatty acids resulted in a significant increase in white muscle texture (hardness, adhesiveness, gumminess, and chewiness) (P < 0.05). With the increase of fatty acid unsaturation, the number of muscle fibers and density were significantly increased (P < 0.05), while the sarcomere length decreased. The gene expression of sirt1 and camk were significantly up-regulated in unsaturated fatty acids groups (P < 0.05), and the genes related to muscle fiber development were also increased significantly (P < 0.05). In vitro study, the primary muscle cells of Megalobrama amblycephala were treated for 24 h according to the references. The results showed that 250 μmol of unsaturated fatty acids OA, LA, and LNA significantly up-regulated the protein levels of p-Ampk, Camk, and Pax7 associated with muscle fiber development (P < 0.05). In conclusion, unsaturated fatty acids can promote muscle fiber development and meat quality because of the different saturations, which may be realized by activating AMPK and Ca2+-dependent signal pathways.

Patterns of alpha-linolenic acid incorporation into phospholipids in H4IIE cells

Alpha linolenic acid (ALA) is an 18-carbon essential fatty acid found in plant-based foods and oils. While much attention has been placed on conversion of ALA to long chain polyunsaturated fatty acids, alternative routes of ALA metabolism exist and may lead to formation of other bioactive metabolites of ALA. The current study employed a non-targeted metabolomics approach to profile ALA metabolites that are significantly upregulated by ALA treatment. H4IIE hepatoma cells (n=3 samples per time point) were treated with 60 μM ALA or vehicle for 0, 0.25, 0.5, 1, 2, 3, 4, 6, 8, and 12 h. Samples were then extracted with methanol and analyzed using high-performance liquid chromatography/quadrupole time-of-flight mass spectrometry. We observed selective changes in ALA incorporation into phospholipid classes and subclasses over the 12 h following ALA treatment. While levels of specific molecular species of ALA-containing phosphatidylcholine, phosphatidylethanolamine, phosphatidylserine, and lysophospholipids were elevated with ALA treatment, others were not affected. Of the phospholipids that were increased, some (e.g., PC[18:3/18:1], PC[18:3/18:4], PE[18:3/18:2], PE[18:3/18:3]) were elevated almost immediately after exposure to ALA, while others [e.g., PE[18:1/18:3] PA[18:3/22:6], and PA[18:3/18:2]) were not elevated until several hours after ALA treatment. Overall, these results suggest that ALA incorporation into phospholipids is selective and support a metabolic hierarchy for ALA incorporation into specific phospholipids. Given the functionality of phospholipids based on their fatty acid composition, future studies will need to investigate the implications of ALA incorporation into specific phospholipids on cell function.

Effects of Arachidonic Acid and Its Metabolites on Functional Beta-Cell Mass.

Arachidonic acid (AA) is a polyunsaturated 20-carbon fatty acid present in phospholipids in the plasma membrane. The three primary pathways by which AA is metabolized are mediated by cyclooxygenase (COX) enzymes, lipoxygenase (LOX) enzymes, and cytochrome P450 (CYP) enzymes. These three pathways produce eicosanoids, lipid signaling molecules that play roles in biological processes such as inflammation, pain, and immune function. Eicosanoids have been demonstrated to play a role in inflammatory, renal, and cardiovascular diseases as well type 1 and type 2 diabetes. Alterations in AA release or AA concentrations have been shown to affect insulin secretion from the pancreatic beta cell, leading to interest in the role of AA and its metabolites in the regulation of beta-cell function and maintenance of beta-cell mass. In this review, we discuss the metabolism of AA by COX, LOX, and CYP, the roles of these enzymes and their metabolites in beta-cell mass and function, and the possibility of targeting these pathways as novel therapies for treating diabetes.

Stearic Acid Activates the PI3K-mTOR-4EBP1/S6K and mTOR-SREBP-1 Signaling Axes through FATP4-CDK1 To Promote Milk Synthesis in Primary Bovine Mammary Epithelial Cells.

Stearic acid (SA), an 18-carbon long-chain saturated fatty acid, has great potential for promoting lactation. Therefore, this study investigates the effects and mechanism of SA on milk synthesis in primary bovine mammary epithelial cells (BMECs). In our study, we found that SA significantly increased β-casein and triglycerides, and the effect was most significant at 100 μM. Signaling pathway studies have found that SA affects milk synthesis by upregulating cyclin-dependent kinase 1 (CDK1) to activate PI3K-mTOR-4EBP1/S6K and mTOR-SREBP-1 pathways. Furthermore, we detected fatty acid transport proteins (FATPs) when BMECs were treated with SA; the mRNA levels of FATP3 (3.713 ± 0.583) and FATP4 (40.815 ± 8.959) were significantly upregulated at 100 μM. Subsequently, we constructed FATP4-siRNA and found that SA was transported by FATP4 into BMECs, promoting milk synthesis. Collectively, these results revealed that SA activated PI3K-mTOR-4EBP1/S6K and mTOR-SREBP-1 signaling axes through FATP4-CDK1 to promote milk synthesis in BMECs.