Specific Fatty Acid Composition Research Articles

Stress-mediated polysorbate 20 degradation and its potential impact on therapeutic proteins.

Polysorbates are the most commonly used surfactants in formulations to stabilize therapeutic proteins against interfacial stresses. Polysorbates can undergo oxidative or enzyme-mediated hydrolytic degradation to produce free fatty acids (FFAs) and subvisible particles in formulations. To determine which product related variables contribute to PS20 degradation, we investigated the effects of storage temperature, formulation, pH, presence of hydrolytic enzymes, and specific fatty acid composition on different grades of PS20 in relation to their PS20 degradation profile and consequently the quality of protein drug products. Bevacizumab and T-DM1 were reformulated in the freshly prepared therapeutic protein formulations containing either compendial PS20 or non-compendial PS20 with high % lauric acid and spiked with exogenous esterase or lipase. The release of FFAs and formation of particles were monitored at 4°C and 37°C. Protein quality was assessed for secondary structures, purity, and biological activity. Hydrolytic release of FFAs and formation of subvisible particles were found to be dependent on grades of PS20, types of enzymes used, incubation temperature, and pH. Esterase- or lipase-mediated degradation of PS20 and formation of subvisible particles in drug formulation showed no significant impact on the biological activity and stability of therapeutic proteins against degradation or aggregation. Our study suggests that degradation of PS20 and formation of FFA particles depend on the fatty acid composition of PS20, types of hydrolytic enzymes, pH, and temperature. The presence of FFA subvisible particles showed no significant impact on the purity and biological activity of the therapeutic proteins under the tested conditions.

Comparative analysis of Camelina sativa and fungal industrial lipases used for biodiesel production

Aim. To identify the genes of false flax (Camelina sativa) endogenous lipases and to analyze the sequence similarity of their key functional domains with those of commercially available lipases. Methods. A detailed search of the databases was carried out in order to identify the sequences of lipases of various species, as well as their sequences were aligned, conservative sequence motifs were identified, the domain structure of the detected proteins was established, and phylogenetic analysis was carried out. Results. 15 triacylglycerol lipase genes were identified, and corresponding sequences of lipases for commercially available products were identified as well. Their domain structure was analyzed, and the level of sequence divergence of their functional regions was also revealed. Conclusions. The lipases that are most similar in terms of sequence and domain organization to the lipases of false flax have been identified, and therefore could potentially be used for more effective transesterification of oil with a specific fatty acid composition for this species.

The Imitation of the Ovarian Fatty Acid Profile of Superfertile Dummerstorf Mouse Lines during IVM of Control Line Oocytes Could Influence Their Maturation Rates.

Declining human fertility worldwide is an attractive research target for the search for "high fertility" genes and pathways to counteract this problem. To study these genes and pathways for high fertility, the superfertile Dummerstorf mouse lines FL1 and FL2 are two unique model organisms representing an improved fertility phenotype. A direct reason for this remarkable characteristic of increased litter size, which reaches >20 pups/litter in both FLs, is the raised ovulation rate by approximately 100%, representing an impressive record in this field. Dummerstorf high-fertility lines incarnate extraordinary and singular models of high-fertility for other species, mostly farm animals, with the aim of improving production and reducing costs. Our main goal is to describe the genetic and molecular pathways to reach their phenotypical excellence, and to reproduce them using the control population. The large litter size and ovulation rate in Dummerstorf lines are mostly due to an increase in the quality of their oocytes, which receive a different intake of fat and are composed of different types and concentrations of fatty acids. As the follicular microenvironment plays a fundamental role during the oocytes development, in the present manuscript, we tried to improve the in vitro maturation technique by mimicking the fatty acid profile of FLs oocytes during the IVM of control oocytes. Currently, the optimization of the IVM system is fundamental mostly for prepubertal girls and oncological patients whose main source of gametes to restore fertility may be their maturation in vitro. Our data suggest that the specific fatty acid composition of FLs COCs can contribute to their high-fertility phenotype. Indeed, COCs from the control line matured in IVM-medium supplemented with C14:0 (high in FL2 COCs) or with C20:0, C21:0, C22:0, and C23:0 (high in FL1 COCs), but also control oocytes without cumulus, whose concentration in long-chain FAs are "naturally" higher, showing a slightly higher maturation rate. These findings represent an important starting point for the optimization of the IVM system using FA supplementation.

Serum Fatty Acid Composition Balance by Fuzzy C-Means Method in Individuals with or without Metabolic Dysfunction-Associated Fatty Liver Disease.

Circulating fatty acid composition is assumed to play an important role in metabolic dysfunction-associated fatty liver disease (MAFLD) pathogenesis. This study aimed to investigate the association between the overall balance of serum fatty acid composition and MAFLD prevalence. This cross-sectional study involved 400 Japanese individuals recruited from a health-screening program. We measured fatty acids in serum lipids using gas chromatography-mass spectrometry. The serum fatty acid composition balance was evaluated using fuzzy c-means clustering, which assigns individual data points to multiple clusters and calculates the percentage of data points belonging to multiple clusters, and serum fatty acid mass%. The participants were classified into four characteristic subclasses (i.e., Clusters 1, 2, 3, and 4), and the specific serum fatty acid composition balance (i.e., Cluster 4) was associated with a higher MAFLD prevalence. We suggest that the fuzzy c-means method can be used to determine the circulating fatty acid composition balance and highlight the importance of focusing on this balance when examining the relationship between MAFLD and serum fatty acids.

The effect of trimethylamine N-oxide on the metabolism of visceral white adipose tissue in spontaneously hypertensive rat

ABSTRACT Strong links have been reported among trimethylamine N-oxide (TMAO), visceral white adipose tissue (vWAT), and cardiometabolic diseases. However, the effects of TMAO on vWAT in hypertension remained incompletely explored. The impact of a chronic 22-week-long treatment with 1 g/L TMAO on vWAT, and its transcriptional and metabolic changes in spontaneously hypertensive rats (SHRs) were evaluated by serum cytokine measurements, histological analysis, fatty acid determinations, and co-expression network analyses. TMAO increased the serum interleukin-6 levels and insulin secretion in SHRs. The adipocyte size was diminished in the SHR 1 g/L TMAO group. In addition, one kind of monounsaturated fatty acids (cis-15-tetracosenoate) and four kinds of polyunsaturated fatty acids (cis-11,14,17-eicosatrienoic acid, docosatetraenoate, docosapentaenoate n-3, and docosapentaenoate n-6) were elevated by TMAO treatment. Three co-expression modules significantly related to TMAO treatment were identified and pathway enrichment analyses indicated that phagosome, lysosome, fatty acid metabolism, valine, leucine, and isoleucine degradation and metabolic pathways were the most significantly altered biological pathways. This study shed new light on the metabolic roles of TMAO on the vWAT of SHRs. TMAO regulated the metabolic status of vWAT, including reduced lipogenesis and an improved specific fatty acid composition. The mechanisms underlying these effects likely involve phagosome and lysosome pathways.

Overwinter Changes in the Lipid Profile of Young-of-the-Year Striped Bass (Morone saxatilis) in Freshwater Ponds.

Young-of-the-year (YOY) striped bass (Morone saxatilis) suffer significant mortality during their first winter. While causes of this mortality are unclear, lipids may play role in adapting to winter stresses, including thermal change and food scarcity. To address this, YOY striped bass were placed in mesh cages in freshwater ponds in the fall (November) and were held until the end of winter, in March. Liver and white muscle tissue were sampled at the beginning and end of the study to compare concentrations of specific lipid classes and fatty acid composition. Muscle-tissue total lipid and triacylglycerol (TAG) was higher in March (late winter) samples. Additionally, concentrations of phosphatidylethanolamine (PE) were higher in the white muscle of striped bass sampled in March; this was accompanied by a decrease in proportions of 18:0 and 22:6n-3 in PE (from ~11 to 7% and 36 to 28%, respectively) and 18:1n-9 and 22:6n-3 in phosphatidylcholine (from ~15 to 10% and 24 to 18%, respectively). This suggests that these fish were not utilizing energy reserves in previously described ways and appear to rely more on other lipid classes or body tissues for overwinter survival than those analyzed in this study.

Comparative Assessment of Physical and Chemical Characteristics of Prickly Pear Seed Oil from Opuntia ficus-indica and Opuntia megacantha Varieties

The prickly pear (Opuntia spp.) is an important plant in the economies of arid and semiarid areas, considering its low agronomic requirements and high water use efficiency. Characterizing the chemical composition of this plant will open new avenues for food, pharmaceutical, and cosmetic applications. In this context, this study examined the physical and chemical parameters of fruit seed oils of two prickly pear species from Rhamna area located in the center of Morocco: Opuntia ficus-indica (OFI), represented by the varieties “Safra” and “Aakria,” and Opuntia megacantha (OM), represented by the variety “Derbana.” The evaluated parameters included oil content, free acidity, specific extinction coefficients (K232 and K270), pigment content, fatty acid, and triglyceride composition. The seed oil contents of the three varieties “Safra,” “Aakria,” and “Derbana” were 8.09%, 8.74%, and 8.04%, respectively. OM (“Derbana”) seed oil was the most stable. The three studied varieties had higher contents of α-pheophytin and carotenoids than that of chlorophyll. Oil from the “Aakria” variety was distinguished by having the highest contents of α-pheophytin and chlorophyll. Significant differences in some fatty acid and triglyceride contents were noted. The major fatty acids of the three varieties were linoleic acid (60.55%–63.46%), followed by oleic acid (18.88%–21.81%) and palmitic acid (13.03%–13.75%). Furthermore, the chromatographic profiles of the triglycerides have shown the dominance of trilinolein (LLL, 24.33%–26.49%) and oleoyl-dilinoleoyl-glycerol (OLL, 20.92%–21.92%). Some triglycerides could be considered species markers, especially OLL, dipalmitoyl-linoleoyl-glycerol (PPL), oleoyl-linoleoyl-linolenoyl-glycerol and palmitoyl-oleoyl-dilinoleoyl-glycerol fraction (OLLn + PoLL), and stearoyl-dioleoyl-glycerol (SOO). This study provides a basis for qualitatively evaluating the therapeutic and cosmetic potential of prickly pear derivatives and for establishing quality standards of seed oil derived from the two species studied.

Supplementation Effect of Oleuropein Extract Combined with Betaine, Magnesium, and Vitamin E on Pigs' Performance and Meat Quality Characteristics.

Simple SummaryOleuropein, betaine, magnesium, and vitamin E show antioxidant and/or metabolic effects on the organism that are reflected, in many cases, in performances and meat quality. This study evaluated whether the combination of these nutrients at two doses manifest different effects on the final product. Both combinations were enough to improve the oxidative status of pigs, although performances were not affected. However, the higher doses increased n-6 and n-3 PUFA in the triglycerides and free fatty acid fractions that resulted in meat that was more susceptible to oxidation.This study evaluates the effect of the dietary combination of oleuropein extract (1200 mg/kg) and betaine (1000 mg/kg), magnesium oxide (600 mg/kg), and α–tocopheryl acetate (400 mg/kg), or a half-dose of these compounds, on pigs’ performance, oxidative status, and meat quality characteristics (drip loss, TBARS, and texture and fatty acid profile of intramuscular fat). Sixty-six barrows and females were slaughtered at 120 kg of BW. Performance and carcass yield were not changed by treatments. The high-dose mixture resulted in higher serum ferric reducing/antioxidant power (p = 0.0026), lower glucose (p = 0.03) and a tendency to have lower serum TBARS (p = 0.07) when compared to control. Percentage of drip loss, moisture content, intramuscular fat, or texture parameters were not modified by dietary treatments. Pigs supplemented with the high-dose mixture had higher PUFA (p = 0.0001), n-6 (p = 0.0001), n-3 (p = 0.0095) and lower MUFA (p = 0.0064) in the neutral lipid fraction of intramuscular fat. Free PUFA, mainly n-3 fatty acids (p = 0.0009), were also higher in the meat of pigs fed the high-dose mixture compared with the others. A higher mobilization (neutral to free fatty acids hydrolysis) of n-3 and MUFA fatty acids in the muscle from pigs fed the high-dose mixture was observed. However, dietary mixture supplementation tended to increase MUFA (p = 0.056) and decrease the total PUFA (p = 0.0074) proportions in muscle polar lipids. This specific fatty acid composition of meat from pigs supplemented with the high-dose mixture could be responsible for the higher meat lipid oxidation observed in this group when compared to the other groups. Consequently, the low-dose mixture would be more adequate for maintaining the oxidative status of pigs and, meat lipid stability.

Plasma and acrosomal membrane lipid content of saltwater crocodile spermatozoa.

This study describes the chemical lipid composition of the sperm plasma and acrosomal membranes of the saltwater crocodile Crocodylus porosus with the aim of providing new insights into sperm physiology, particularly that associated with their preservation ex vivo . The specific fatty acid composition of the sperm plasma and acrosomal membranes is documented. The mean (±s.d.) ratio of unsaturated to saturated membrane fatty acids within the plasma membrane was 2.57±0.50, and was determined to be higher than a similar analysis of the lipids found in the acrosomal membrane (0.70±0.10). The saltwater crocodile sperm plasma membrane also contained remarkably high levels of cholesterol (mean (±s.d.) 40.7±4.5 nmol per 106 sperm cells) compared with the spermatozoa of other amniote species that have so far been documented. We suggest that this high cholesterol content could be conferring stability to the crocodile sperm membrane, allowing it to tolerate extreme osmotic fluxes and rapid changes in temperature. Our descriptive analysis now provides those interested in reptile and comparative sperm physiology an improved baseline database for interpreting biochemical changes associated with preservation pathology (e.g. cold shock and cryoinjury), epididymal sperm maturation and capacitation/acrosome reaction.

A predicted transmembrane region in plant diacylglycerol acyltransferase 2 regulates specificity toward very-long-chain acyl-CoAs

Triacylglycerols are the main constituent of seed oil. The specific fatty acid composition of this oil is strongly impacted by the substrate specificities of acyltransferases involved in lipid synthesis, such as the integral membrane enzyme diacylglycerol acyltransferase (DGAT). Two forms of DGAT, DGAT1 and DGAT2, are thought to contribute to the formation of seed oil, and previous characterizations of various DGAT2 enzymes indicate that these often are associated with the incorporation of unusual fatty acids. However, the basis of DGAT2's acyl-donor specificity is not known because of the inherent challenges of predicting structural features of integral membrane enzymes. The recent characterization of DGAT2 enzymes from Brassica napus reveals that DGAT2 enzymes with similar amino acid sequences exhibit starkly contrasting acyl-donor specificities. Here we have designed and biochemically tested a range of chimeric enzymes, substituting parts of these B. napus DGAT2 enzymes with each other, allowing us to pinpoint a region that dramatically affects the specificity toward 22:1-CoA. It may thus be possible to redesign the acyl-donor specificity of DGAT2 enzymes, potentially altering the fatty acid composition of seed oil. Further, the characterization of a DGAT2 chimera between Arabidopsis and B. napus demonstrates that the specificity regulated by this region is transferrable across species. The identified region contains two predicted transmembrane helices that appear to reoccur in a wide range of plant DGAT2 orthologues, suggesting that it is a general feature of plant DGAT2 enzymes.

The integration of fatty acid biomarkers of trophic ecology with pollutant body-burdens of PAHs and PCBs in four species of fish from Sabine Lake, Texas

This study investigated whether the composition of fatty acids in hepatic tissue of four fish species from Sabine Lake (TX), influenced hepatic body-burdens of pollutants. The multivariate correlations between hepatic body-burdens of sixteen polycyclic aromatic hydrocarbons (PAHs) and twenty-nine polychlorinated biphenyls (PCBs), with thirty-seven fatty acids was studied. The trophic ecology of fish was determined using stomach content analysis and by comparing characteristic fatty acid profiles. The fish species studied included: bull shark (Carcharhinus leucas), alligator gar (Atractosteus spatula), red drum (Sciaenops ocellatus), and gafftopsail catfish (Bagre marinus). Assessment of fish stomach contents demarcated catfish and red drum (mainly invertebrate diet) vs. alligator gars and bull sharks (mainly teleost diet). Elevated levels (45× higher) of nervonic acid (24:1n9) also placed the trophic ecology of catfish and red drum closer to the base of the marine/estuarine food web of Sabine Lake, as compared to alligator gars and bull sharks. PAH profiles showed a predominance of low molecular weight PAHs (≤3 aromatic rings) in catfish, red drum and alligator gars. Bull sharks exhibited the highest levels for select high molecular weight PAHs (≥ 4 aromatic rings). The overall predominance of low molecular weight PAHs indicated exposure to mainly petrogenic sources of PAHs. Bull sharks and alligator gars also exhibited the highest body-burdens of PCBs. The risk assessment of dioxin-like PCBs showed median toxic equivalent (TEQ) values in bull sharks to be the highest, and above the upper toxicity thresholds for adverse effects in fish and aquatic mammals. The multivariate correlational analysis of pollutant body-burdens and fatty acid levels showed no clear correlation of the pollutants with any particular type of fatty acid (unsaturated vs. saturated, short-chain vs. very-long chain). This result indicates that pollutant bioaccumulation was not associative with the specific fatty acid composition of lipids in the fish from Sabine Lake.

Salmo salar fish waste oil: Fatty acids composition and antibacterial activity.

Background and aimsFish by-products are generally used to produce fishmeal or fertilizers, with fish oil as a by-product. Despite their importance, fish wastes are still poorly explored and characterized and more studies are needed to reveal their potentiality. The goal of the present study was to qualitatively characterize and investigate the antimicrobial effects of the fish oil extracted from Salmo salar waste samples and to evaluate the potential use of these compounds for treating pathogen infections.MethodsSalmo salar waste samples were divided in two groups: heads and soft tissues. Fatty acids composition, and in particular the content in saturated (SAFAs), mono-unsaturated (MUFAs) and Polyunsaturated (PUFAs) fatty acids, was characterized through GC/MS Thermo Focus GC-DSQ II equipped with a ZB-5 fused silica capillary tubes column. The antimicrobial activity of the salmon waste oils was evaluated through the Minimum Inhibitory Concentration assay and the antibiotics contamination was determined by Liquid Chromatography with tandem Mass Spectrometry (LC-MS/MS) analysis. All experiments were done at least in triplicate.ResultsGC/MS analysis has shown the specific fatty acid composition of the salmon waste oils and their enrichment in MUFAs and PUFAs, with special reference to omega-3, -6, -7, -9 fatty acids. Furthermore, our study has highlighted the antimicrobial activity of the fish waste oil samples against two Gram+ and Gram- bacterial strains.ConclusionsThese data confirm that the fish waste is still quantitatively and qualitatively an important source of available biological properties that could be extracted and utilized representing an important strategy to counteract infective diseases in the context of the circular economy.

Distinguishing Features of Fatty Acid Content and Composition in Total Lipids of Malusorientalis Uglitzk. Pericarp

Composition and content of fatty acids were examined in total lipids of pericarpic tissues in the oriental wild apple (Malus orientalis Uglitzk.) grown in mountain regions of the North Caucasus. The fatty acids (FA) in pericarp outer layers (epidermis and hypodermis) and pericarp parenchymal parts were characterized by a comparatively low unsaturation index (UI): 0.902 and 1.115, respectively. This was caused by a relatively low content of polyunsaturated FA (34% in the outer pericarp parts and 45% in the pericarp parenchyma) with respect to the total FA content as well as by high level of saturated very-long-chain fatty acids (VLCFA) (15% in the pericarp outer parts). These values are in a marked contrast to those previously found for a similarly distributed cultural apple tree (Malus domestica Borkh.) that originated from M. orientalis as a parental species. The sum of diene- and triene-containing FA in M. domestica reached 59 and 76% in the pericarpic outer and parenchymal parts, respectively, and the sum of all VLCFA in the outer part of the pericarp did not exceed 1.7%. Such significant differences in fatty acid composition of lipids for related Malus species appeared during long-term selection of the domestic apple tree. On the one hand, M. orientalis, featuring a relatively low UI due to specific fatty acid composition of lipids, is less adapted to temperature stress and drought. In M. domestica, the cold and drought tolerance is corrected by artificial selection for this trait during breeding of cultivated varieties. On the other hand, the lipids of the oriental apple contain a high amount of VLCFA, which probably restricts the pericarp growth by regulating cell proliferation. At the same time, the abundance of VLCFA enhances plant resistance to fungal diseases, a property lost during the breeding of domestic apple.

Fatty acid profiles of typical dietary lipids after gastrointestinal digestion and absorbtion: A combination study between in-vitro and in-vivo

The objective of the present study was to investigate the influences of dietary lipid composition on the gastrointestinal digestion and postprandial serum lipid profiles, and the connections between them. The in-vitro digestion results showed that maximum free fatty acid (FFA) release level of different lipid samples was PO (Palm oil) > RO (Rapeseed oil) > LINO (Linseed oil) > SO (Sunflower oil) > LO (Lard oil), and the first-order kinetics apparent rate constant was PO > SO ≈ RO > LO ≈ LINO, this may probably be ascribed to their specific lipid fatty acid composition and TAG structure. The individual FFA released during 240 min in-vitro digestion time was measured, and it showed that the release rate of short-chain saturated fatty acids (e.g. C16:0 in PO) were higher than the long-chain poly-unsaturated fatty acids (e.g. C18:3n-3 in LINO). Besides, the position of fatty acids within TAG molecules could also impose influences on the lipid hydrolysis process upon pancreas lipase in gastrointestinal tract using in-vitro digestion model. The postprandial serum fatty acid composition of the adult SD male rats were examined within 240 min after oral gavage administration, and the Pearson correlations between lipid fatty acid composition and the serum fatty acid profiles were analyzed. Certain correlations were summarized between lipid compositions (i.e. fatty acid composition and TAG structure), lipid digestion fates and serum fatty acid content in postprandial. The present work may provide some basic understandings of the connections among lipid compositions, lipid gastrointestinal digestion differences and the postprandial serum lipid profiles, and provide useful information about their nutritional and functional evaluation.

Association of NEFA composition with insulin sensitivity and beta cell function in the Prospective Metabolism and Islet Cell Evaluation (PROMISE) cohort.

Our aim was to determine the longitudinal associations of individual NEFA with the pathogenesis of diabetes, specifically with differences in insulin sensitivity and beta cell function over 6years in a cohort of individuals who are at risk for diabetes. In the Prospective Metabolism and Islet Cell Evaluation (PROMISE) longitudinal cohort, 477 participants had serum NEFA measured at the baseline visit and completed an OGTT at three time points over 6years. Outcome variables were calculated using the OGTT values. At each visit, insulin sensitivity was assessed using the HOMA2 of insulin sensitivity (HOMA2-%S) and the Matsuda index, while beta cell function was assessed using the insulinogenic index over HOMA-IR (IGI/IR) and the insulin secretion-sensitivity index-2 (ISSI-2). Generalised estimating equations were used, adjusting for time, waist, sex, ethnicity, baseline age, alanine aminotransferase (ALT) and physical activity. NEFA were analysed as both concentrations (nmol/ml) and proportions (mol%) of the total fraction. Participants' (73% female, 70% with European ancestry) insulin sensitivity and beta cell function declined by 14-21% over 6years of follow-up. In unadjusted models, several NEFA (e.g. 18:1 n-7, 22:4 n-6) were associated with lower insulin sensitivity, however, nearly all of these associations were attenuated in fully adjusted models. In adjusted models, total NEFA, 16:0, 18:1 n-9 and 18:2 n-6 (as concentrations) were associated with 3.7-8.0% lower IGI/IR and ISSI-2, while only 20:5 n-3 (as mol%) was associated with 7.7% higher HOMA2-%S. Total NEFA concentration was a strong predictor of lower beta cell function over 6years. Our results suggest that the association with beta cell function is due to the absolute size of the serum NEFA fraction, rather than the specific fatty acid composition.

Characterization of the Mechanisms of Daptomycin Resistance among Gram-Positive Bacterial Pathogens by Multidimensional Lipidomics.

Previous work suggests that altered lipid metabolism may be associated with daptomycin resistance in Gram-positive pathogens, but lipidomic changes underlying resistance are not fully understood. We performed untargeted lipidomics by using three-dimensional hydrophilic interaction liquid chromatography-ion mobility-mass spectrometry (HILIC-IM-MS) to characterize alterations in the lipidomes of daptomycin-susceptible and -resistant isogenic strain pairs of Enterococcus faecalis, Staphylococcus aureus, and Corynebacterium striatum. We first validated the HILIC-IM-MS method by replicating the expected alterations of phospholipid metabolism in the previously studied E.faecalis strain pairs, such as reduced phosphatidylglycerols (PGs), while also revealing additional changes in cardiolipins (CLs), lysyl-PGs, and glycolipids. Whole-genome sequencing of the S.aureus and C.striatum strains found that daptomycin resistance was associated with mutations in pgsA, which encodes phosphatidylglycerophosphate synthase, as well as mutations in genes affecting fatty acid biosynthesis and cell wall metabolism. Lipidomics revealed significantly decreased levels of PGs, CLs, and amino acid-modified PGs, as well as accumulation of lipids upstream of PGs, such as glycolipids and phosphatidic acids, in the resistant strains. Notably, the glycolipids, diglucosyldiacylglycerols, were significantly elevated in a fatty acid-dependent manner in the daptomycin-resistant S.aureus strain. In daptomycin-resistant C.striatum, which has a unique cell envelope architecture, the glycolipids, glucuronosyldiacylglycerols, and phosphatidylinositols were significantly elevated. These results demonstrate that alteration of lipid metabolism via mutations in pgsA is a common mechanism of daptomycin resistance in two distinct species of Gram-positive bacteria and point to the potential contribution of altered glycolipid and fatty acid compositions to daptomycin resistance. IMPORTANCE This work comprehensively characterizes lipidomic changes underlying daptomycin resistance in three Gram-positive bacterial species, E.faecalis, S.aureus, and C.striatum, by using a novel three-dimensional lipidomics methodology based on advanced mass spectrometry. We demonstrated a number of advantages of our method in comparison with other methods commonly used in the field, such as high molecular specificity, sensitivity, and throughput. Whole-genome sequencing of the S.aureus and C.striatum strains identified mutations in pgsA, which encodes phosphatidylglycerophosphate synthase, in both resistant strains. Lipidomics revealed significantly decreased levels of lipids downstream of PgsA, as well as accumulation of lipids upstream of PgsA in the resistant strains. Furthermore, we found that changes in individual molecular species of each lipid class depend on the their specific fatty acid compositions. The characteristic changes in individual lipid species could be used as biomarkers for identifying underlying resistance mechanisms and for evaluating potential therapies.

Visualization of local phosphatidylcholine synthesis within hippocampal neurons using a compartmentalized culture system and imaging mass spectrometry

Neurons extend neurites with an increased synthesis of phosphatidylcholine (PC) that is not only a membrane component but also a functional regulator with specific fatty acid composition. To analyze the local synthesis of the PC molecular species within neurons, we combined a compartmentalized culture system with matrix-assisted laser desorption/ionization imaging mass spectrometry (MALDI-IMS). We observed that a newly synthesized PC, which contains exogenously administered palmitic acid-d3, is accumulated at the cell bodies and the tips of the distal neurites. The local accumulation within distal neurites is formed by distinct metabolic activity from cell bodies, suggesting that the local extracellular composition of free fatty acid can be a key to regulate specific functions of each PC molecular species. We expect our simple method to be a starting point for more sophisticated in vitro analytical methods for unveiling detailed lipid metabolisms within neurons.

South African Cactus Pear Seed Oil: A Comprehensive Study on 42 Spineless Burbank Opuntia ficus‐indica and Opuntia robusta Cultivars

Cactus pear fruit seeds contain oil that can be utilized for human consumption. Forty‐two South African cultivars are evaluated over two seasons for seed oil content and fatty acid composition in an attempt to ascertain the best oil yielding cultivar. Seed oil content varied among cultivars and seasons and the yield ranged between 4.09 and 8.76% of seed mass. The unsaturated fatty acids are the most prominent and were dominated by linoleic acid, which varied between 56.86 and 65.21%, followed by oleic acid (16.44 and 22.51%), while the saturated fatty acids palmitic and stearic acid content ranged from 12.72 to 16.05% and from 2.21 to 3.39%, respectively. Cultivar and variation in rainfall have a statistically significant effect on cactus pear seed oil content and fatty acid composition. Principal Component Analysis show that certain cultivars are exclusively associated with specific characteristics. This is the most comprehensive study of the seed oil characteristics of the available cultivars in South Africa ever to be performed. The American Giant cultivar have the highest seed oil yield.Practical Applications: In a semi‐arid country such as South Africa, the value of by‐products and waste products from a drought resistant plant such as cactus pear should be emphasized. Cactus pear seed oil is a novel and expensive essential oil. The emergence of many small‐holding farms and small‐scale processing facilities necessitated a comprehensive investigation into the oil composition of all the available cactus pear cultivars. Essential knowledge regarding cultivar choice in terms of oil‐production and specific fatty acid composition, as well as seasonal effects thereon, is generated with this research. This research indicats that the American Giant (Opuntia ficus‐indica) cultivar have the highest oil yield wheras the Roly Poly cultivar have the highest linoleic acid content. This data will enable processors to make recommendations to producers to use cultivars with optimum yield and oil quality as production target.Cactus pear fruit seeds contain oil that can be utilized for human consumption. Forty‐two South African cultivars are evaluated over two seasons for seed oil content and fatty acid composition in an attempt to ascertain the best oil yielding cultivar.

Arachidonic acid and fatty acid profiles as indicators of contamination from the leachates of animal carcasses

Because many livestock with avian influenza and foot and mouth disease have been disposed of at landfills, underground water contamination is a big problem for people living near these landfills as well as burial sites. Biological oxygen demand (BOD), NH4, total dissolved solids (TDS), chloride and potassium have been used as markers of contamination from the leachates of animal carcasses. However, livestock manure and vegetable oils from compost are also a source of these markers. In this study, we propose arachidonic acid (C20:4) as a specific indicator of leachates from animal carcasses, and the presence of arachidonic acid in underground water is suggested to be a potential marker of contamination from the leachates of animal carcasses. Based on the specific fatty acid composition, the fatty acid profiles of the carcass leachates, livestock manure and vegetable oil were examined, and multidimensional scaling (MDS) analyses of the fatty acids showed pronounced differences between the carcass leachates, livestock manure and vegetable oils in this study. MDS analyses of fatty acids can also be used as a potential indicator of contamination from the leachates of animal carcasses in groundwater.

Analysis of genetic diversity and fatty acid composition in a prebreeding material of Jatropha

Genetic and fatty acid variability in four datasets of accessions and prebreeding lines of Jatropha curcas was analyzed. The datasets were comprised of J. curcas accessions (13), BC1 (28), BC1F2 (12) and single seeds (12). The BC1, BC1F2 and single seed dataset were derived from an interspecific cross between J. curcas and J. integerrima. The average within-group (within dataset) polymorphism revealed by AFLP markers was 28.5 %. The average genetic similarity within the four datasets, namely, J. curcas accessions, BC1, BC1F2 and single seeds was 0.92, 0.82, 0.90 and 0.92 respectively with an overall average genetic similarity of 0.80. The values of percent polymorphism, Shannon’s information index and expected heterozygosity were highest for BC1 dataset. The total unsaturated fatty acids in the oil varied from 63.64 to 89.10 %. Levene’s test showed that within-group variance was significantly different for three fatty acids, namely, palmitic acid, oleic acid and linoleic acid. BC1F2 dataset had the highest variance for palmitic and oleic acid, whereas BC1 dataset had the highest variance for linoleic acid. The results revealed that both genetic as well as fatty acid variability was significantly higher in the newly created prebreeding lines and the level of fatty acid variability in these datasets was different and highly correlated to the level of their genetic variability as revealed by AFLP markers. This new prebreeding material, especially, the BC1 and BC1F2 lines, will be useful for development of Jatropha varieties with specific fatty acid composition for specific industrial applications.