Global analysis of N-myristoylation and its heterogeneity by combining N-terminomics and nanographite fluoride-based solid-phase extraction.

N-myristoylation is one of the most widespread and important lipidation in eukaryotes and some prokaryotes, which is formed by covalently attaching various fatty acids (predominantly myristic acid C14:0) to the N-terminal glycine of proteins. Disorder of N-myristoylation is critically implicated in numerous physiological and pathological processes. Here, we presented a method for purification and comprehensive characterization of endogenous, intact N-glycine lipid-acylated peptides, which combined the negative selection method for N-terminome and the nanographite fluoride-based solid-phase extraction method (NeS-nGF SPE). After optimizing experimental conditions, we conducted the first global profiling of the endogenous and heterogeneous modification states for N-terminal glycine, pinpointing the precise sites and their associated lipid moieties. Totally, we obtained 76 N-glycine lipid-acylated peptides, including 51 peptides with myristate (C14:0), 10 with myristoleate (C14:1), 6 with tetradecadienoicate (C14:2), 5 with laurate (C12:0) and 4 with lauroleate (C12:1). Therefore, our proteomic methodology could significantly facilitate precise and in-depth analysis of the endogenous N-myristoylome and its heterogeneity.

A metabolic labeling protocol to enrich myristoylated proteins from Caenorhabditis elegans.

Myristoylation is a type of lipidation with important functions. Owing to the lack of high-quality antibodies against myristoylation, developing alternative methods for profiling myristoylated proteins is important. Here, we provide a protocol for metabolic labeling using click chemistry to profile myristoylated proteins in C. elegans. Our approach improves the signal/noise ratio by covalently linking the myristoylated proteins to the beads. This protocol provides a highly specific and reproducible way for enriching myristoylated proteins, which could be modified to analyze other types of lipidations. For complete details on the use and execution of this protocol, please refer to Tang et al. (2021).

Transfer of Lauric and Myristic Acid from Black Soldier Fly Larval Lipids to Egg Yolk Lipids of Hens Is Low.

Implementing insects, such as the black soldier fly larvae (BSFL), as animal feed commonly includes the previous removal of substantial amounts of fat. This fat may represent an as yet underutilized energy source for livestock. However, transfer of lauric and myristic acid, prevalent in BSFL fat and undesired in human nutrition, into animal-source foods like eggs may limit its implementation. To quantify this, a laying hen experiment was performed comprising five different diets (10 hens/diet). These were a control diet with soybean oil and meal and a second diet with soybean oil but with partially defatted BSFL meal as protein source. The other three diets were based on different combinations of partially defatted BSFL meal and fat obtained by two different production methods. Lauric acid made up half of the BSFL fat from both origins. Both BSFL fats also contained substantial amounts of myristic and palmitic acid. However, in the insect-based diets, the net transfer from diet to egg yolk was less than 1% for lauric acid, whereas the net transfer for myristic and palmitic acid was about 30% and 100%, respectively. The net transfer did not vary between BSFL originating from production on different larval feeding substrates. The results illustrate that hens are able to metabolize or elongate very large proportions of ingested lauric acid and myristic acid, which are predominant in the BSFL lipids (together accounting for as much as 37 mol%), such that they collectively account for less than 3.5 mol% of egg yolk fatty acids.

Computational and experimental validation of free radical scavenging properties of high-performance thin-layer chromatography quantified phenyl myristate in Homalium nepalense.

Phenyl myristate was isolated from Homalium nepalense, which is known for its therapeutic virtues in traditional medicine. However, the study of radical scavenging-capacity of phenyl myristate is limited by its relatively low abundance in medicinal plants. We have studied the isolation, structure-elucidation, and bioactivities of high-performance thin-layer chromatography validated phenyl myristate from hydroalcohol-extract of bark of H. nepalense. The chemical structure of phenyl myristate was elucidated by spectroscopic methods. The chromatography was performed on high-performance thin-layer chromatography aluminum plates coated with silica-gel 60 F254 . Determination and quantitation of phenyl myristate were performed by densitometric-scanning at 254 nm (chloroform-methanol, 9:1, v/v; Rf 0.49). The method was validated according to International Council for Harmonisation guidelines in terms of linearity, specificity, sensitivity, accuracy, precision, robustness, and stability. Linearity-range of phenyl myristate was 100-500 ng/5 µL with correlation-coefficient r2  = 0.9997. Limits of detection and quantitation were 3.35 and 10.17 ng, respectively. Phenyl myristate showed significant free-radical-scavenging activities in 2,2-diphenyl-1-picrylhydrazyl, oxygen-radical-absorbance-capacity, and ex vivo cell-based-antioxidant-protection-in-erythrocytes assays. Molecular-docking approach of phenyl myristate showed effective binding at active sites of human serum albumin (HSA) with the lowest binding energy (-8.4 kcal/mol) that was comparable with ascorbic acid (-5.0 kcal/mol). These studies provide mechanistic insight into the potential free radical scavenging activities of phenyl myristate.

Detection of Heterogeneous Protein S-Acylation in Cells.

The use of synthetically synthesized azide and alkyne fatty acid analogs coupled with bioorthogonal Cu(I)-catalyzed Huisgen 1,3-dipolar cycloaddition reaction-based detection methods to study protein S-acylation reactions has replaced the traditional method of using in vivo metabolic radiolabeling with tritiated palmitic acid and has greatly facilitated our understanding of this essential cellular process. Here, we describe the chemical synthesis of myristic (C:14), palmitic (C16:0), and stearic (C18:0) acid-azide probes and detail how they may be utilized as chemical reporters for the analysis of S-acylation of exogenously expressed proteins in cells.

Alyssum homolocarpum seed oil (AHSO), containing natural alpha linolenic acid, stearic acid, myristic acid and ß-sitosterol, increases proliferation and differentiation of neural stem cells in vitro.

BACKGROUND: Embryonic neural stem cells (eNSCs) are immature precursors of the central nervous system (CNS), with self-renewal and multipotential differentiation capacities. These are regulated by endogenous and exogenous factors such as alpha-linolenic acid (ALA), a plant-based essential omega-3 polyunsaturated fatty acid. METHODS: In this study, we investigated the effects of various concentrations of Alyssum homolocarpum seed oil (AHSO), containing natural ALA, stearic acid (SA), myristic acid (MA), and ß-sitosterol, on proliferation and differentiation of eNSCs, in comparison to controls and to synthetic pure ALA. RESULTS: Treatment with natural AHSO (25 to 75 µM), similar to synthetic ALA, caused a significant ~ 2-fold increase in eNCSs viability, in comparison to controls. To confirm this proliferative activity, treatment of NSCs with 50 or 75 µM AHSO resulted in a significant increase in mRNA levels of notch1, hes-1 and Ki-67and NICD protein expression, in comparison to controls. Moreover, AHSO administration significantly increased the differentiation of eNSCs toward astrocytes (GFAP+) and oligodendrocytes (MBP+) in a dose dependent manner and was more potent than ALA, at similar concentrations, in comparison to controls. Indeed, only high concentrations of 100 µM AHSO, but not ALA, caused a significant increase in the frequency of neurons (ß-III Tubulin+). CONCLUSION: Our data demonstrated that AHSO, a rich source of ALA containing also other beneficial fatty acids, increased the proliferation and stimulated the differentiation of eNSCs. We suggest that AHSO's effects are caused by ß-sitosterol, SA and MA, present within this oil. AHSO could be used in diet to prevent neurodevelopmental syndromes, cognitive decline during aging, and various psychiatric disorders.

Fatty acid profile and oxidation tests of fat extracted from yogurt using rose hip seed oil.

BACKGROUND: Yogurt is a dairy product with a high nutritional value. However, like all milk products, it contains milk fat and is rich in saturated fatty acids. It would be desirable to enrich dairy products in poly- unsaturated fatty acids to increase dietary intake amongst consumers and improve their health. Also, some LAB bacteria are able to produce CLA and CLnA isomers from linoleic and linolenic acids. The aim of this study was to investigate the chemical properties and fatty acid profile of yogurt with the addition of 3.5% of rose hip seed oil. METHODS: Yogurt was made from skimmed milk and yogurt starter culture YC-180 Ch. Hansen (Denmark), with the addition of 3.5% of rose hip seed oil. The peroxide value, acid value, iodine value, TBA rate and fatty acid profile were determined in fat extracted from the yogurt after 1 and 14 days of storage and in fresh rose hip seed oil. The fatty acid profile was determined using gas chromatographic methods with mass spectrometric detectors. RESULTS: Fat extracted from the yogurts had lower levels of peroxides than the fresh oil. It was more acidic and the iodine value was higher than in the fresh oil. Rose hip seed oil enriched the product with polyunsaturated fatty acids. After 14 days of storage, linoleic and linolenic acid levels had increased. Moreover, the content of myristic and palmitic acids had decreased. CONCLUSIONS: The rose hip seed oil added to the yogurt was less susceptible to oxidation. The content of un- saturated fatty acids in the yogurt increased with the addition of the oil, making yogurt with rose hip seed oil an excellent source of Ω-3 and Ω-6 fatty acids. Conjugated linoleic (CLA) and linolenic (CLnA) acids were not detected. However, yogurt manufactured with appropriate adjunct cultures and with the correct oil addition could be a natural source of CLA and CLnA in the human diet.

Evidence for N-Terminal Myristoylation of Tetrahymena Arginine Kinase Using Peptide Mass Fingerprinting Analysis.

In this study, we confirmed N-terminal myristoylation of Tetrahymena pyriformis arginine kinase (AK1) by identifying a myristoylation signal sequence at the N-terminus. A sufficient amount of modified enzyme was synthesized using an insect cell-free protein synthesis system that contains all of the elements necessary for post-transcriptional modification by fatty acids. Subsequent peptide mass fingerprinting (PMF) analyses were performed after digestion with trypsin. The PMF data covered 39 % (143 residues) of internal peptides. The target N-myristoylated peptide had a theoretical mass of 832.4477 and was clearly observed with an experimental mass (m/z-H(+)) of 832.4747. The difference between the two masses was 0.0271, supporting the accuracy of identification and indicating that the synthesized T. pyriformis AK1 is myristoylated. The fixed specimens of T. pyriformis were reacted with an anti-AK1 peptide antibody followed by a secondary antibody with a fluorescent chromophore and were observed using immunofluorescence microscope. In agreement with previous western blotting analyses, microscopic observations suggested that AK1 is localized in the cilia. The present PMF and microscopic analyses indicate that T. pyriformis AK1 may be localized and anchored to ciliary membranes via N-terminal myristoyl groups.

Metabonomic Study of Biochemical Changes in Human Hair of Heroin Abusers by Liquid Chromatography Coupled with Ion Trap-Time of Flight Mass Spectrometry.

Hair analysis is with the advantage of non-invasive collection and long surveillance window. The present study employed a sensitive and reliable liquid chromatography coupled with ion trap-time of flight mass spectrometry method to study the metabonomic characters in the hair of 58 heroin abusers and 72 non-heroin abusers. Results indicated that certain endogenous metabolites, such as sorbitol and cortisol, were accelerated, and the level of arachidonic acid, glutathione, linoleic acid, and myristic acid was decreased in hair of heroin abusers. The metabonomic study is helpful for further understanding of heroin addiction and clinical diagnosis.

Chemical characterization and antioxidant activity of Amazonian (Ecuador) Caryodendron orinocense Karst. and Bactris gasipaes Kunth seed oils.

Nowadays, data concerning the composition of Caryodendron orinocense Karst. (Euphorbiaceae) and Bactris gasipaes Kunth (Arecaceae) seed oils are lacking. In light of this fact, in this paper fatty acids and unsaponifiable fraction composition have been determined using GC-MS, HPLC-DAD (Diode Array Detector), NMR approaches and possible future applications have been preliminary investigated through estimation of antioxidant activity, performed with DPPH test. For C. orinocense linoleic acid (85.59%) was the main component, lauric (33.29%) and myristic (27.76%) acids were instead the most abundant in B. gasipaes. C. orinocense unsaponifiable fraction (8.06%) evidenced a remarkable content of ß-sitosterol, campesterol, stigmasterol, squalene and vitamin E (816 ppm). B. gasipaes revealed instead ß-sitosterol and squalene as main constituents of unsaponifiable matter (3.01%). Antioxidant capacity evidenced the best performance of C. orinocense seed oil. These preliminary results could be interesting to suggest the improvement of the population's incomes from Amazonian basin. In particular the knowledge of chemical composition of C. orinocense and B. gasipaes oils could be helpful to divulge and valorize these autochthones plants.

Calmodulin dependent protein kinase II activation by exercise regulates saturated & unsaturated fatty acids and improves some metabolic syndrome markers.

AIMS: Activation of Calmodulin dependent protein kinase (CaMK)-II by exercise has a plethora of benefits in health. Fatty acids play a pivotal role in the pathogenesis of metabolic syndrome (MetS). Prevention of MetS and treatment of its main characteristics are very significant to fight against type 2 diabetes. CaMKII activation in the regulation of saturated and unsaturated fatty acids in relation to type 2 diabetes and MetS has not been studied, which became the focus of this present study. MAIN METHODS: Using Gas chromatography-Mass spectrometry, we investigated saturated fatty acids and unsaturated fatty acids. Quantitative real time PCR was also used to assess the gene expression. KEY FINDINGS: Results indicate that both palmitoleic acid and oleic acid which are monounsaturated fatty acids were increased in response to CaMKII activation. On the other hand, myristic acid and palmitic acid which are saturated fatty acids known to increase the risk factors of MetS and type 2 diabetes were decreased by exercise induction of CaMKII. Conversely, lauric acid also a saturated fatty acid was increased in response to CaMKII activation by exercise. This fatty acid is known to have beneficial effects in alleviating symptoms of both type 2 diabetes and MetS. SIGNIFICANCE: According to our knowledge, this is the first study to show that CaMKII activation by exercise regulates fatty acids essential in type 2 diabetes and MetS. CaMKII can be an avenue of designing novel therapeutic drugs in the management and treatment of type 2 diabetes and MetS.

Identification of fatty acids in canine seminal plasma.

Seminal plasma contains various biochemical components associated with sperm function. However, there is limited information regarding the fatty acid composition of seminal plasma and their effect on sperm. The aim of this study was to identify the fatty acid content in canine seminal plasma using gas chromatography. Twelve ejaculates were studied, the seminal plasma was obtained by centrifugation and then the lipids were extracted, methylated and analysed by chromatography. The total lipids in the seminal plasma were 2.5 ± 0.3%, corresponding to 85% saturated fatty acids (SFA) and 15% unsaturated fatty acids (UFA). The greatest proportions of SFA were palmitic acid (30.4%), stearic acid (23.4%) and myristic acid (5.3%) and of UFA oleic acid (9.0%). Therefore, the protocols and techniques used enabled the identification of 18 different fatty acids in canine seminal plasma, which constitutes a good method to evaluate and quantify the fatty acid profile in this species.

Chemical composition of volatiles from Opuntia littoralis, Opuntia ficus-indica, and Opuntia prolifera growing on Catalina Island, California.

The essential oils from the cladodes of Opuntia littoralis, Opuntia ficus-indica and Opuntia prolifera growing wild on Santa Catalina Island, California, were obtained by hydrodistillation and analysed by gas chromatography-mass spectrometry (GC-MS). Terpenoids were the dominant class of volatiles in O. littoralis, with the two main components being the furanoid forms of cis-linalool oxide (10.8%) and trans-linalool oxide (8.8%). Fatty acid-derived compounds dominated the essential oil of O. ficus-indica with linoleic acid (22.3%), palmitic acid (12.7%), lauric acid (10.5%) and myristic acid (4.2%) as major fatty acids. O. prolifera oil was composed of 46.6% alkanes and the primary hydrocarbon component was heptadecane (19.2%). Sixteen compounds were common to all the three Opuntia species.

[Changes in the content of plasma lipoproteins in persons subjected to diets prepared with sunflower oil alone or mixed with palm olein]. / Modificaciones de las lipoproteínas del plasma en voluntarios sometidos a dietas preparadas con aceite de girasol solo o mezclado con oleina de palma.

We analyzed in 31 subjects, regular guests of the University food service of the Central University of Venezuela (UCVFS), in Caracas, the effects of replacing sunflower oil, commonly used in the preparation of meals, by a mix of sunflower oil and palm olein 70/30 (v/v) respectively. Plasma concentrations of total cholesterol, low and very low density lipoproteins were not changed after 40 days of the substitution. On the contrary, concentrations of high density lipoprotein and total triglycerides increased. The resistance to the oxidation of low-density lipoproteins increased considerably (p < 0.01). Today this resistance is considered as a protective factor of great importance in the prevention of the initiation of the atherogenic process. Taking into account the favorable modifications of HDL cholesterol and the clear increased resistance to the oxidation of LDL, we think that palm olein, mixed with other oils with a high ratio linoleic/palmitic (sunflower, corn, soya an the likes), can be used as a healthy alternative in human nutrition.

Modificaciones de las lipoproteínas del plasma en voluntarios sometidos a dietas preparadas con aceite de girasol solo o mezclado con oleína de palma / Changes in the content of plasma lipoproteins in persons subjected to diets prepared with sunflower oil alone or mixed with palm olein

En 31 comensales regulares del Comedor Universitario de la Universidad Central de Venezuela (CUUCV), en Caracas. Se observó el efecto de la sustitución del aceite de girasol que se utiliza corrientemente en la preparación de las comidas en ese comedor, por un aceite obtenido de la mezcla de aceite de girasol y oleína de palma, en la proporción 70/30 (v/v) respectivamente. Después de 40 días continuos de la sustitución no hubo cambios significativos en las concentraciones de colesterol total (CT), ni del colesterol de las lipoproteínas de baja densidad (LDL) y muy baja densidad (VLDL). La concentración del colesterol de las lipoproteínas de alta densidad (HDL) aumentó significativamente (p<0,05). Los triglicéridos (TG) del plasma aumentaron en un 30%. La resistencia a la oxidación de las LDL aumentó considerablemente (p< 0,01). Hoy se considera a esta resistencia como un factor protector de gran importancia en la prevención del inicio del proceso aterogénico. Tomando en cuenta las modificaciones favorables como el aumento de colesterol de HDL sin modificación de la LDL y el claro aumento de la resistencia a la oxidación de la LDL, se considera que la oleína de palma es un aceite vegetal que puede ser utilizado sin mayores riesgos en mezcla con otros aceites que tengan una relación linoleico/palmítico más elevada como los aceites de girasol, maíz, soja y otros.

We analyzed in 31 subjects, regular guests of the University food service of the Central University of Venezuela (UCVFS), in Caracas, the effects of replacing sunflower oil, commonly used in the preparation of meals, by a mix of sunflower oil and palm olein 70/30 (v/v) respectively. Plasma concentrations of total cholesterol, low and very low density lipoproteins were not changed after 40 days of the substitution. On the contrary, concentrations of high density lipoprotein and total triglycerides increased. The resistance to the oxidation of low-density lipoproteins increased considerably (p<0, 01). Today this resistance is considered as a protective factor of great importance in the prevention of the initiation of the atherogenic process. Taking into account the favorable modifications of HDL cholesterol and the clear increased resistance to the oxidation of LDL, we think that palm olein, mixed with other oils with a high ratio linoleic/palmític (sunflower, corn, soya an the likes), can be used as a healthy alternative in human nutrition.

Sterol regulatory element binding transcription factor 1 (SREBF1) polymorphism and milk fatty acid composition.

Milk is known to contain high concentrations of saturated fatty acids-such as palmitic (16:0), myristic (14:0), and lauric (12:0) acids-that can raise plasma cholesterol in humans, making their presence in milk undesirable. The main objective of our candidate gene study was to develop genetic markers that can be used to improve the healthfulness of bovine milk. The sterol regulatory element binding transcription factor 1 (SREBF1) known to regulate the transcription of lipogenic genes together with SREBF chaperone and insulin induced gene 1 were the candidate genes. The results showed significant association of the overall SREBF1 haplotypes with milk production and variations in lauric (12:0) and myristic (14:0) acid concentrations in milk. Haplotype H1 of SREBF1 was the most desirable to improve milk healthfulness because it was significantly associated with lower lauric (12:0) and myristic (14:0) acid concentrations compared with haplotype H3 of SREBF1, and lower lauric acid (12:0) concentration compared with haplotype H2 of SREBF1. Haplotype H1 of SREBF1, however, was significantly associated with lower milk production compared with haplotype H3 of SREBF1. We did not detect any significant associations between genetic polymorphisms in insulin induced gene 1 (INSIG1) and SREBF chaperone and milk fatty acid composition. In conclusion, genetic polymorphisms in SREBF1 can be used to develop genetic tools for the selection of animals producing milk with healthier fatty acid composition.

[Study on chemical constituents of volatile oil from rhizomes and leaves of Pileostegia viburnoides var. glabrescens by GC-MS].

OBJECTIVE: To analyze the chemical constituents of volatile oil from the rhizomes and leaves of Pileostegia viburnoides var. glabrescens by GC-MS. METHODS: The volatile oil was extracted from the rhizomes and leaves of Pileostegia viburnoides var. glabrescens by steam distillation. The constituents of volatile oil were identified by GC-MS technology. RESULTS: 37 compounds were identified from the oil of rhizomes. 36 compounds were identified from the oil of leaves. The rhizomes and leaves volatile oil had 18 compounds in common. CONCLUSION: This study is the first one to report the volatile components of Pileostegia viburnoides var. glabrescens. It can provide a scientific basis for rational use of the rhizomes and leaves of Pileostegia viburnoides var. glabrescens.

A comparison of the physicochemical properties and fatty acid composition of indaiá (Attalea dubia) and Babassu (Orbignya phalerata) oils.

The physicochemical properties and fatty acid composition of Attalea dubia (Mart.) Burret (indaiá) seed oil were investigated. The oil was extracted in a soxhlet apparatus using petroleum ether and evaluated for iodine, acid, peroxide, ester, and saponification values. The oil was also analyzed using infrared and nuclear magnetic resonance spectroscopy. The fatty acid profile of the oil was determined by GC-MS. For each analysis indaiá oil was compared to Orbignya phalerata (babassu) oil. The two oils appeared to be very similar in their fatty acid composition, in which lauric acid (the most abundant), myristic acid, caprylic acid, and capric acid were the four main fatty acids detected. The unsaturated fatty acids content was lower for indaiá oil (5.8%) than for babassu oil (9.4%). The results suggest that indaiá palm tree could be cultivated as a new source of vegetable oil with potential for food and cosmetic industries.