Odd Chain Research Articles

Phase shift of solitary wave in a one-dimensional granular chain

In this paper, both the fifth-order Runge–Kutta numerical scheme and binary collision approximation are used to study the phase shift. Both numerical and theoretical results are shown that the solitary wave after head-on collision propagates along the chain behind the reference wave in both even and odd numbers of grain chains. It is the well-known feature of the appearance of the phase shift. Those results are in agreement with the experimental results. Furthermore, it is found that the phase shift is not only related to the collision position of the waves, but also to the position where the time is measured. The value of phase shift increases nonmonotonously with increasing the velocity of the opposite propagation of the wave. Binary collision approximation is applied to analyze the phase shift, and it is found that theoretical results agree well with numerical results, especially in the case of phase shift in odd chain.

Solubility of Cellulose in Binary Mixtures of 1-Alkyl-3-methylimidazolium Acetate and Dimethyl Sulfoxide: Influence of Alkyl Chain Length in the Cation

The influence of alkyl chain length of cations on cellulose solubility in a neat imidazolium (MIM)-based ionic liquid (IL) [CnMIM][OAc] and [CnMIM][OAc]–DMSO binary system (n=0–6) was investigated. The correlation between cellulose solubility and Kamlet–Taft hydrogen bond basicity (β) was also examined. Cellulose solubility (g per mol IL) in neat [CnMIM][OAc] increased as the cation alkyl chain length decreased from 6 to 2. However, alkyl chain lengths of 1 and 0 resulted in extremely poor cellulose solubility, indicating that a chain length of 2 was optimal for dissolution of cellulose in the system. Cellulose solubility in the [CnMIM][OAc]–DMSO binary system (n=1–6) was greater than that in neat IL, with maximum solubility occurring at an IL mole fraction of ~0.2. Maximum cellulose solubility in the [CnMIM][OAc]–DMSO binary system was slightly better at even alkyl chain lengths (n=2, 4, or 6) than at odd chain lengths (n=1, 3, or 5), with the best solubility at n=4. More interestingly, maximum cellulose solubility and specific IL mole fraction in the IL-DMSO binary system were related with the β values of neat ILs, even with ILs containing different anionic species or cation alkyl chain lengths. This indicates that solubility information in IL-DMSO binary systems is influenced by the characteristics of neat ILs.

Organic acid disorders.

Organic acids (OAs) are intermediary products of several amino acid catabolism or degradation via multiple biochemical pathways for energy production. Vitamins or co-factors are often quintessential elements in such degradation pathways and OA metabolism. OAs that result from enzyme defects in these pathways can be identified in body fluids utilizing gas chromatography-mass spectrometry techniques (GC/MS). OAs are silent contributor to acid base imbalance and can affect nitrogen balance and recycling. Since OA production occurs in distal steps of a specific amino acid catabolism, offending amino acid accumulation is not characteristic. OA disorders as inborn errors of metabolism (IEM) are included in differential diagnosis of metabolic acidosis, as the common mnemonic MUDPILES taught in medical schools. High anion gap metabolic acidosis with hyperammonemia is a characteristic OA biochemical finding. VOMIT (valine, odd chain fatty acids, methionine, isoleucine, and threonine) is a smart acronym and a common clinical presentation of OA disorders and can present as early life-threatening illness, prior to Newborn Screening results availability. Easy identification and available medical formula make the field of metabolic nutrition vital for management of OA disorders. Treatment strategies also involve cofactor/vitamin utilization to aid specific pathways and disorder management. Optimal metabolic control and regular monitoring is key to long-term management and prevention of morbidity, disability and mortality. Prompt utilization of acute illness protocol (AIP) or emergency protocol and disorder specific education of family members or caregivers, primary care physicians and local emergency health care facilities; cautiously addressing common childhood illnesses in patients with OA disorders, can help avoid poor short- and long-term morbidity, disability and mortality outcomes.

Label-Free Quantitative Proteomics in a Methylmalonyl-CoA Mutase-Silenced Neuroblastoma Cell Line.

Methylmalonic acidemias (MMAs) are inborn errors of metabolism due to the deficient activity of methylmalonyl-CoA mutase (MUT). MUT catalyzes the formation of succinyl-CoA from methylmalonyl-CoA, produced from propionyl-CoA catabolism and derived from odd chain fatty acids β-oxidation, cholesterol, and branched-chain amino acids degradation. Increased methylmalonyl-CoA levels allow for the presymptomatic diagnosis of the disease, even though no approved therapies exist. MMA patients show hyperammonemia, ketoacidosis, lethargy, respiratory distress, cognitive impairment, and hepatomegaly. The long-term consequences concern neurologic damage and terminal kidney failure, with little chance of survival. The cellular pathways affected by MUT deficiency were investigated using a quantitative proteomics approach on a cellular model of MUT knockdown. Currently, a consistent reduction of the MUT protein expression was obtained in the neuroblastoma cell line (SH-SY5Y) by using small-interfering RNA (siRNA) directed against an MUT transcript (MUT siRNA). The MUT absence did not affect the cell viability and apoptotic process in SH-SY5Y. In the present study, we evaluate and quantify the alterations in the protein expression profile as a consequence of MUT-silencing by a mass spectrometry-based label-free quantitative analysis, using two different quantitative strategies. Both quantitative methods allowed us to observe that the expression of the proteins involved in mitochondrial oxido-reductive homeostasis balance was affected by MUT deficiency. The alterated functional mitochondrial activity was observed in siRNA_MUT cells cultured with a propionate-supplemented medium. Finally, alterations in the levels of proteins involved in the metabolic pathways, like carbohydrate metabolism and lipid metabolism, were found.

Optimization of odd chain fatty acid production by Yarrowia lipolytica

BackgroundOdd chain fatty acids (odd FAs) have a wide range of applications in therapeutic and nutritional industries, as well as in chemical industries including biofuel. Yarrowia lipolytica is an oleaginous yeast considered a preferred microorganism for the production of lipid-derived biofuels and chemicals. However, it naturally produces negligible amounts of odd chain fatty acids.ResultsThe possibility of producing odd FAs using Y. lipolytica was investigated. Y. lipolytica wild-type strain was shown able to grow on weak acids; acetate, lactate, and propionate. Maximal growth rate on propionate reached 0.24 ± 0.01 h−1 at 2 g/L, and growth inhibition occurred at concentration above 10 g/L. Wild-type strain accumulated lipids ranging from 7.39 to 8.14% (w/w DCW) depending on the carbon source composition, and odd FAs represented only 0.01–0.12 g/L. We here proved that the deletion of the PHD1 gene improved odd FAs production, which reached a ratio of 46.82% to total lipids. When this modification was transferred to an obese strain, engineered for improving lipid accumulation, further increase odd FAs production reaching a total of 0.57 g/L was shown. Finally, a fed-batch co-feeding strategy was optimized for further increase odd FAs production, which generated 0.75 g/L, the best production described so far in Y. lipolytica.ConclusionsA Y. lipolytica strain able to accumulate high level of odd chain fatty acids, mainly heptadecenoic acid, has been successfully developed. In addition, a fed-batch co-feeding strategy was optimized to further improve lipid accumulation and odd chain fatty acid content. These lipids enriched in odd chain fatty acid can (1) improve the properties of the biodiesel generated from Y. lipolytica lipids and (2) be used as renewable source of odd chain fatty acid for industrial applications. This work paves the way for further improvements in odd chain fatty acids and fatty acid-derived compound production.

Exchange between macrophyte and mangrove organic matter input in estuarine systems: drought implications

Paq proxy was applied on mid and long-chain n-alkanes in order to develop an index to assist in the long-term assessment of changes and exchanges between aquatic communities in estuarine environments as a result of increased saline incursion. New boundaries are proposed according to n-alkanes abundance in the leaves of local mangrove tree species for better definition of emergent aquatic plant end-member. Molecular distribution and δ13C isotopic signatures of n-alkanes were also used to support the parameter. A predominance of odd carbon-numbered long chain (> C27 n-alkanes) indicated a main terrestrial input, although mid-chain n-alkanes (23 and 25 carbons) were also identified. Short-chain n-alkanes (< 19) were absent or found in a very small concentration. Carbon Preference Index and C/N ratio reinforced a terrestrial origin for the sedimentary organic matter. δ13C signatures of n-alkanes for C23, C25, C29 and C31 were characteristic of mangrove input, ranging from -27.57 ‰ (C23) to -34.40 ‰ (C29) for Piraquê-Mirim River (PM) and from -27.36 ‰ (C23) to -32.84 ‰ (C31) for Piraquê-Açu River (PA) without any particular trend. Paq proxy was successfully used to identify rises in marine macrophytes (mid-chain n-alkanes) input mainly in the confluence and PM probably as consequence of drought periods. The confluence presented a mixing sources of OM. PA was identified as a stable mangrove environment while PM was characterized by pulses of marine macrophytes input and should be managed with care in respect to its catchment for water use and dam constructions as a shortage of fresh water can alter the estuarine ecology.

Fatty acid synthesis pathway provides lipid precursors for rhamnolipid biosynthesis in Burkholderia thailandensis E264

Rhamnolipid production was monitored for a period of 216 h using different substrates in Pseudomonas aeruginosa PAO1 and Burkholderia thailandensis E264 which showed comparable crude yields attained by both after 216 h. The crude yield for P. aeruginosa, however, was significantly higher at the early stages of fermentation (72 or 144 h). Additionally, P. aeruginosa produced rhamnolipid with odd and even carbon chain lipid moieties using odd carbon chain fatty acid substrates (up to 45.97 and 67.57%, respectively). In contrast, B. thailandensis produced rhamnolipid with predominantly even carbon chain lipid moieties (up to 99.26). These results indicate the use of the fatty acid synthesis (FAS II) pathway as the main source of lipid precursors in rhamnolipid biosynthesis by B. thailandensis. Isotope tracing using 0.25% stearic acid – d35 + 1% glycerol as carbon substrate showed a single pattern of deuterium incorporation: with predominantly less than 15 deuterium atoms incorporated into a single Di-C14-C14 rhamnolipid molecule. This further indicates that the FAS II pathway is the main source of the lipid precursor in rhamnolipid biosynthesis by B. thailandensis. The pathogenicity of these strains was also assessed, and results showed that B. thailandensis is significantly less pathogenic than P. aeruginosa with an LC50 at 24 h > 2500, approximately three logs higher than P. aeruginosa using the Galleria mellonella larva model.

Dysfunctional Plasma Lipid Metabolism Contributes to Chronic Migraine Pathology

BackgroundLipids are a major storage form of energy, and the source of inflammatory and pain signaling molecules, yet their contribution to chronic migraine (CM) is not fully known. Our aim is to determine if plasma lipid metabolism contributes to CM pathology.MethodsWe obtained plasma from healthy controls (CT, n=10) or CM subjects (n=17) diagnosed using the International Headache Society criteria, and measured unesterified (UFA), and esterified fatty acids (EFA) using gas chromatography‐mass spectrometry. Plasma glycerophospholipids (GP) and sphingolipids (SP) were determined using LC‐MS/MS and phospholipase A2 (PLA2) activity was determined using fluorescent substrates.ResultsAge, gender distribution, and BMI were similar, but while 48 % and 35 % of CM participants were on NSAIDs or taking anti‐oxidants, respectively, no CT subjects were on medications. Unesterified levels of three even chain saturated fatty acids (SAFA), two odd chain SAFAs, the sum of even chain SAFAs, sum of SAFAs, six even chain monounsaturated fatty acids (MUFA), 2 odd chain MUFAs, five omega‐3 (n−3) polyunsaturated fatty acids (PUFA), and five omega‐6 (n−6) PUFAs are higher in CM. The sum of all UFAs is significantly elevated in CM plasma. Esterified levels of two even chain SAFAs, the sum of even chain SAFAs, one odd chain SAFAs, the sum of all SAFAs, five even chain MUFAs, three odd chain MUFAs, five n−3 PUFAs, the sum of n−3 PUFAs, and three n−6 PUFAs, are higher in CM plasma. For both UFA and EFA, only the C16:1 composition was significantly higher in CM plasma. The ratios C16:1/C16:0 and C20:4n−6/homo‐γ‐C20:3n−6 representative of delta‐9 and delta‐5 desaturases, respectively, are higher in CM. While PLA2 activity was similar, the UFA to EFA ratio of even chain MUFA and the sum of MUFAs is higher in CM. Elongase indices < C18:0 were lower and indices >C20:0 were higher in CM. Of all GP/SPs detected, only ceramide composition is lower (p=0.0003) in CM (0.26 ± 0.07) compared to CT (0.48 ± 0.06). The ceramide to dihydroceramide and ceramide to sphingomyelin ratios are also significantly lower in CM.ConclusionSince plasma UFAs are known to correspond to adipose tissue levels, higher plasma fatty acids and UFA/EFA ratios suggest enhanced mobilization from adipose storage sites in CM. Higher C16:1 composition concomitant with an increase in the C16:1/C16:0 ratio suggests increased delta‐9 desaturase activity in CM. Lower ceramide ratios suggest reduced de novo synthesis and/or hydrolysis of sphingomyelin. Together, these studies show dysfunctional lipid metabolism in CM. We propose that controlling plasma lipid metabolism may relieve CM symptoms.Support or Funding InformationRecruitment and sample collection at Stanford University School of Medicine was supported by generous gifts from the Higgins Family Trusts. Lipid analyses was supported by NIH 5R01NSO72497 and HMRI.This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Dairy Products, Dairy Fatty Acids, and the Prevention of Cardiometabolic Disease: a Review of Recent Evidence.

To examine recent literature on dairy products, dairy fatty acids, and cardiometabolic disease. Primary questions of interest include what unique challenges researchers face when investigating dairy products/biomarkers, whether one should consume dairy to reduce disease risk, whether dairy fatty acids may be beneficial for health, and whether one should prefer low- or high-fat dairy products. Dairy composes about 10% of the calories in a typical American diet, about half of that coming from fluid milk, half coming from cheese, and small amounts from yogurt. Most meta-analyses report no or weak inverse association between dairy intake with cardiovascular disease and related intermediate outcomes. There is some suggestion that dairy consumption was inversely associated with stroke incidence and yogurt consumption was associated with lower risk of type 2 diabetes. Odd chain fatty acids (OCFAs) found primarily in dairy (15:0 and 17:0) appear to be inversely associated with cardiometabolic risk, but causation is uncertain. Substitution analyses based on prospective cohorts suggested that replacing dairy fat with vegetable fat or polyunsaturated fat was associated with significantly lower risk of cardiovascular disease. Current evidence suggests null or weak inverse association between consumption of dairy products and risk of cardiovascular disease. However, replacing dairy fat with polyunsaturated fat, especially from plant-based foods, may confer health benefits. More research is needed to examine health effects of different types of dairy products in diverse populations.

Discrimination of haymilk and conventional milk via fatty acid profiles

Milk produced by feeding silage-free feed has become popular in Europe. This kind of milk has recently been recognized as “traditional speciality guaranteed” by the European Union. As a consequence, an analytical discrimination of this silage-free produced milk quality has become necessary. In this study, discrimination of “haymilk” (HM) from conventional milk (CM) in retail samples was attempted taking in consideration all feeding seasons. For analytical discrimination, a partial least square discriminant analysis (PLS-DA) to fatty acids methyl esters (FAMEs) obtained from analysis by gas chromatography was applied. All groups of long-chain fatty acids, including saturated, odd chain fatty acids, mono- and polyunsaturated fatty acids of both cis/trans configuration, contributed to discrimination of the two types of milk, where alpha linolenic acid (+ 37% in HM) and conjugated linoleic acid (C18:2c9t11—+ 22% in HM) were the most relevant for calibration. Applying PLS-DA was successful in discriminating CM and HM from retail milk in all seasons. From 48 identified fatty acids, 18 showed different levels in CM and HM samples and could be used for discrimination of the two groups. The method was able to discriminate HM and CM produced in the cold season, but showed unclear results in the warm season due to a higher scattering of both groups. These higher deviations were attributed to the fact that most dairy cows are able to consume fresh grass during summer. Although it is not possible to discriminate HM and CM produced in warm season, the fatty acid pattern of HM can be taken as a reference, from which a properly produced HM should not deviate. A separate calibration for each season is recommended for optimal results.

Proposal of a Linear Retention Index System for Improving Identification Reliability of Triacylglycerol Profiles in Lipid Samples by Liquid Chromatography Methods.

The retention index system was proposed in 1958 by Kováts. It is based on the correlation between the retention time of the analytes and the ones of a series of reference standards, making retention data dependent on the chromatographic phenomenon only, viz., on the three-term interaction analyte-stationary phase-mobile phase. Particularly in GC, because the mobile phase has a negligible influence, the retention of the analytes depends almost entirely on the stationary phase and it is as independent as possible from operating conditions. This makes retention index databases usable in samples identification at both the intra- and interlaboratory levels. The scope of this research was to create a similar identification system in LC, where the identification of unknowns is still a challenge because of the unavailability of spectral databases related to the low reproducibility of mass spectra generated by means of the atmospheric pressure ionization technique normally interfaced to LC. Lipid compounds, specifically triacylglycerols, were selected as target analytes mainly due to their regular chromatographic LC profile under reversed phase conditions. The odd carbon chain number triacylglycerol series from trinonain to trinonadecanoin was chosen as the basis of the retention index scale and a database of 209 triacylglycerols was built. For this purpose an ultra high-performance LC method, able to maximize the baseline separation of triacylglycerols in different real-world samples (vegetable oils, fish, and milk samples) was developed.

Profile study contribution of the odd chain fatty acids for qualifying of the final products of Alentejo local pig breed fattened on diets of montanheira

Within our studies of the profile of fatty acids of emerging row of the Portuguese autochthonous Alentejo local pig breed, we decided to emphasize the importance of odd chain fatty acids in the qualification and distinction of their final products. Therefore, we used samples of dorsal subcutaneous fat of 36 carcasses of Alentejo local pig breed (18♂♂castrated and 18♀♀females) spread over two (2) lots with different food management in the fattening stage (Lote1, n = 24, regime feed montanheira and the final third with herb spontaneous pasture and corn grain and Lote2, n = 12, feeding of montanheira and the final third with herb spontaneous pasture and triticale grain). From the analysis of the results, on average, in sums of odd chain fatty acids (Lote1 = 0.66 ± 0.13 and Lote2 =1.02 ± 0.33), we’ve found that the Lote2 showed a highly significant difference (P≤0.001) in relation to Lote1, which enabled us to distinguish the final products derived from the carcasses of pigs consumed grass and triticale in the final third of montanheira in maize. Thus, we conclude that by using the % of the sum of the profile of the odd-chain fatty acids it is possible to disentangle (fresh and / or processed end products) from the Alentejo local pig breed, according to the diet of grazing in the montanheira and, simultaneously, the substitution of corn in grain by triticale grains in animal husbandry will facilitate the mitigation of scarcity and food shortages caused by the degradation of the Mediterranean ecosystem.

Rapid atmospheric transport and large-scale deposition of recently synthesized plant waxes

Sedimentary plant wax 2H/1H ratios are important tools for understanding hydroclimate and environmental changes, but large spatial and temporal uncertainties exist about transport mechanisms from ecosystem to sediments. To assess atmospheric pathways, we collected aerosol samples for two years at four locations within a ∼60 km radius in northern Switzerland. We measured n-alkane distributions and 2H/1H ratios in these samples, and from local plants, leaf litter, and soil, as well as surface sediment from six nearby lakes. Increased concentrations and 2H depletion of long odd chain n-alkanes in early summer aerosols indicate that most wax aerosol production occurred shortly after leaf unfolding, when plants synthesize waxes in large quantities. During autumn and winter, aerosols were characterized by degraded n-alkanes lacking chain length preferences diagnostic of recent biosynthesis, and 2H/1H values that were in some cases more than 100‰ higher than growing season values. Despite these seasonal shifts, modeled deposition-weighted average 2H/1H values of long odd chain n-alkanes primarily reflected summer values. This was corroborated by n-alkane 2H/1H values in lake sediments, which were similar to deposition-weighted aerosol values at five of six sites. Atmospheric deposition rates for plant n-alkanes on land were ∼20% of accumulation rates in lakes, suggesting a role for direct deposition to lakes or coastal oceans near similar production sources, and likely a larger role for deposition on land and transport in river systems. This mechanism allows mobilization and transport of large quantities of recently produced waxes as fine-grained material to low energy sedimentation sites over short timescales, even in areas with limited topography. Widespread atmospheric transfer well before leaf senescence also highlights the importance of the isotopic composition of early season source water used to synthesize waxes for the geologic record.

Analysis of the biosynthetic process of fatty acids in Thraustochytrium

Thraustochytrium is a marine protist producing a specific profile of nutritionally important fatty acids, including very long chain polyunsaturated fatty acids (VLCPUFAs) docosahexaenoic acid (DHA, 22:6n-3), even chain saturated fatty acids (SFAs) palmitic acid (16:0), and odd chain SFAs pentadecanoic acid (15:0). To study how these fatty acids are synthesized, a series of radiolabeled precursors were used to trace the biosynthetic process in vivo and in vitro. When Thraustochytrium was fed with long chain fatty acid intermediates such as [1–14C]-oleic acid, [1–14C]-linoleic acid and [1–14C]-α-linolenic acid, no VLCPUFAs were produced, indicating that the aerobic pathway for the biosynthesis of VLCPUFAs was not functional in Thraustochytrium. When fed with [1–14C]-acetic acid, both SFAs and VLCPUFAs were labeled, and when fed with [1–14C]-propionic acid, mainly SFAs were labeled. However, when fed with [1–14C]-acetic acid in the presence of cerulenin, a type I FAS inhibitor, only VLCPUFAs were labeled, and when fed with [1–14C]-propionic acid in the presence of cerulenin, neither SFAs nor VLCPUFAs were labeled. This result clearly indicates that the type I fatty acid synthase (FAS) in Thraustochytrium could use acetic acid and propionic acid as the primers to synthesize even chain and odd chain SFAs, respectively, and VLCPUFAs were synthesized by the PUFA synthase using acetic acid as the primer. In addition, radioactive acetic acid could label both phospholipids (PL) and triacylglycerols (TAG), and VLCPUFAs appeared first and were largely accumulated in PL, whereas TAG accumulated much more SFAs than VLCPUFAs. The in vitro assay with [1–14C]-malonyl-CoA in presence of cerulenin showed that the crude protein of Thraustochytrium produced only VLCPUFAs, not SFAs, further confirming the role of the PUFA synthase in the biosynthesis of VLCPUFAs. Collectively, these results have elucidated the biochemical mechanisms for the biosynthesis of all fatty acids in Thraustochytrium.

Relative Validity and Reproducibility of a Food Frequency Questionnaire for Assessing Dietary Intakes in a Multi-Ethnic Asian Population Using 24-h Dietary Recalls and Biomarkers.

The assessment of diets in multi-ethnic cosmopolitan settings is challenging. A semi-quantitative 163-item food frequency questionnaire (FFQ) was developed for the adult Singapore population, and this study aimed to assess its reproducibility and relative validity against 24-h dietary recalls (24 h DR) and biomarkers. The FFQ was administered twice within a six-month interval in 161 adults (59 Chinese, 46 Malay, and 56 Indian). Fasting plasma, overnight urine, and 24 h DR were collected after one month and five months. Intra-class correlation coefficients between the two FFQ were above 0.70 for most foods and nutrients. The median correlation coefficient between energy-adjusted deattenuated FFQ and 24 h DR nutrient intakes was 0.40 for FFQ1 and 0.39 for FFQ2, highest for calcium and iron, and lowest for energy and carbohydrates. Significant associations were observed between urinary isoflavones and soy protein intake (r = 0.46), serum carotenoids and fruit and vegetable intake (r = 0.34), plasma eicosapentaenoic acid and docosahexaenoic acid (EPA + DHA) and fish/seafood intake (r = 0.36), and plasma odd chain saturated fatty acids (SFA) and dairy fat intake (r = 0.25). Associations between plasma EPA + DHA and fish/seafood intake were consistent across ethnic groups (r = 0.28–0.49), while differences were observed for other associations. FFQ assessment of dietary intakes in modern cosmopolitan populations remains feasible for the purpose of ranking individuals’ dietary exposures in epidemiological studies.

Unravelling a role of LRPPRC in peroxisomal lipid metabolism through lipidomic investigations in human and mouse

RationaleLRPPRC (leucine‐rich pentatricopeptide repeat‐containing protein) is commonly described as a regulator of RNA metabolism in both mitochondria and nuclei, but the overall biological impact of this role remains unclear. Integrative genomics analyses have revealed that mutations in the LRPPRC gene were causing the cytochrome c oxidase defect in the French‐Canadian variant of Leigh Syndrome (LSFC) (Mootha et al. 2003). More recently, a targeted metabolomics study in LSFC patients highlighted specific markers reflecting mitochondrial metabolic perturbations for various nutrients including fatty acids (Thompson‐Legault et al. 2015). The role of LRPPRC in lipid metabolism remains, however, to be better deciphered.Goal & MethodsTo dissect the role of LRPPRC in lipid metabolism, we have analyzed plasma from LSFC patients as well as plasma and livers from hepato‐specific KO‐LRPPRC mice using a combination of mass spectrometry (MS)‐based approaches. These include: (1) an untargeted and comprehensive lipidomic workflow, which enables the coverage of > 1300 unique lipid entities, and (2) targeted lipidomic analyses to probe fatty acid (FA) metabolism through acylcarnitines (ACs) profiling (covering >100 species) or cholesterol catabolism into bile acids (BAs; 9 (un)conjugated species).ResultsThe lipidomic profile observed in LSFC patients is typically characteristic of peroxisomal dysfunction as revealed by a: (i) 2‐fold decrease in plasmalogens (Pls; p<0.01), (ii) 2‐fold decrease in conjugate BAs such as glyco‐(G), glycodeoxy‐(GD) (p<0.001) and tauro‐(T) (p<0.05) cholic acids (CA), and (iii) 1.5‐fold increase in specific AC species, namely those with odd chains or > 20 carbons (p<0.05). These results in humans were corroborated in transgenic mice. Indeed, in plasma, there is a 1.5‐fold decrease in Pls (p<0.05). In addition, in liver, several results point out to a remodeling of peroxisomal metabolism. These include: (i) an imbalance in BA conjugation (10‐fold increase in CA, p<0.01; 1.4‐fold decrease in GDCA, p<0.05) and a 4‐ to 10‐fold increase in odd chain and >20 carbons ACs (p<0.01). This notion is further substantiated by changes in gene and/or protein expression levels for: (i) catalase, a classical marker of peroxisome content (+16%; protein, p<0.001), (ii) ACOX1, marker of peroxisomal β‐oxidation (−40%; protein, p<0.05) and (iii) several peroxins (Pex) involved in peroxisome biogenesis and transport, namely Pex11β, Pex14, Pex19, Pex1 and Pex 10 (up to +60%; mRNA; p<0.05).ConclusionCollectively there results highlight a novel role for LRPPRC in the regulation of lipid metabolism beyond mitochondria, namely in peroxisomes. Whether peroxisomal lipid perturbations are specific to LRPPRC gene defect or represent a common feature of mitochondrial dysfunction remain, however, to be further ascertained.Support or Funding InformationThis work was supported by the “Fondation Grand défi Pierre Lavoie”.

Linear ion-trap MSn with high-resolution MS reveals structural diversity of 1-O-acylceramide family in mouse epidermis

1-O-acylceramide is a new class of epidermal cer-amide (Cer) found in humans and mice. Here, we report an ESI linear ion-trap (LIT) multiple-stage MS (MSn) approach with high resolution toward structural characterization of this lipid family isolated from mice. Molecular species desorbed as the [M + H]+ ions were subjected to LIT MS2 to yield predominately the [M + H - H2O]+ ions, followed by MS3 to cleave the 1-O-acyl residue to yield the [M + H - H2O - (1-O-FA)]+ ions. The structures of the N-acyl chain and long-chain base (LCB) of the molecule were determined by MS4 on [M + H - H2O - (1-O-FA)]+ ions that yielded multiple sets of specific ions. Using this approach, isomers varied in the 1-O-acyl (from 14:0- to 30:0-O-acyl) and N-acyl chains (from 14:0- to 34:1-N-acyl) with 18:1-sphingosine as the major LCB were found for the entire family. Minor isomers consisting of 16:1-, 17:1-, 18:2-, and 19:1-sphingosine LCBs with odd fatty acyl chain or with monounsaturated N- or O-fatty acyl substituents were also identified. An estimation of more than 700 1-O-acylceramide species, largely isobaric isomers, are present, underscoring the complexity of this Cer family.

Odd Chain Fatty Acids; New Insights of the Relationship Between the Gut Microbiota, Dietary Intake, Biosynthesis and Glucose Intolerance

Recent findings have shown an inverse association between circulating C15:0/C17:0 fatty acids with disease risk, therefore, their origin needs to be determined to understanding their role in these pathologies. Through combinations of both animal and human intervention studies, we comprehensively investigated all possible contributions of these fatty acids from the gut-microbiota, the diet, and novel endogenous biosynthesis. Investigations included an intestinal germ-free study and a C15:0/C17:0 diet dose response study. Endogenous production was assessed through: a stearic acid infusion, phytol supplementation, and a Hacl1−/− mouse model. Two human dietary intervention studies were used to translate the results. Finally, a study comparing baseline C15:0/C17:0 with the prognosis of glucose intolerance. We found that circulating C15:0/C17:0 levels were not influenced by the gut-microbiota. The dose response study showed C15:0 had a linear response, however C17:0 was not directly correlated. The phytol supplementation only decreased C17:0. Stearic acid infusion only increased C17:0. Hacl1−/− only decreased C17:0. The glucose intolerance study showed only C17:0 correlated with prognosis. To summarise, circulating C15:0 and C17:0 are independently derived; C15:0 correlates directly with dietary intake, while C17:0 is substantially biosynthesized, therefore, they are not homologous in the aetiology of metabolic disease. Our findings emphasize the importance of the biosynthesis of C17:0 and recognizing its link with metabolic disease.

Calorimetric investigation on three-ring chain ethylene-bridge liquid crystalline compounds with terminal odd carbon chain

The stabilities and the phase transition sequences of two ethylene-bridge fluorinated liquid crystals have been examined using the differential scanning calorimeter; and the repeatability and reliability for these phase transitions also have been verified. Furthermore, we report molar heat capacities of these two fluorinated liquid crystals measured using a Quantum Design physical properties measurement system with specific heat option within the temperature range from 1.9 to 300 K. The heat capacities of these two compounds increase with the temperature increasing, and no thermal anomalies have been found in the entire temperature region; and also the heat capacity values of 5-BB2B-F are larger than those of 3-BB2B-F due to the molecular weight difference even though they are homologous. The experimental data have been fitted to a function of T with a series of theoretical and empirical models for the proper temperature ranges. Thermodynamic function values \(C_{\text{p,m}}^{0} ,\Delta_{ 0}^{{\text{T}}} S_{\text{m}}^{\text{o}}\) and \(\Delta_{ 0}^{\text{T}} H_{\text{m}}^{\text{o}}\) at T = (0.5–300) K have been calculated based on these fitting results. The standard molar heat capacities, entropies and enthalpies of 3-BB2B-F and 5-BB2B-F at 298.15 K and 0.1 MPa have been determined to be \(C_{\text{p,m}}^{\text{o}}\) = (450.02 ± 4.50) J K−1 mol−1 and (478.08 ± 4.78) J K−1 mol−1, \(S_{\text{m}}^{\text{o}}\) = (443.91 ± 4.44) J K−1 mol−1 and (486.85 ± 4.87) J K−1 mol−1 and \(H_{\text{m}}^{\text{o}}\) = (66.47 ± 0.66) kJ mol−1 and (72.66 ± 0.73) kJ mol−1, respectively.

Estimations of Polycyclic Aliphatic Hydrocarbon and Total Petroleum Hydrocarbon in Aquatic Faunas Found in Foccardos Terminal River in Port Harcourt, Rivers State

Increasing water bodies and water inhabitants’ pollution has posed a great global concern as aquatic animals are continually endangered with effluents from various sources. Polycyclic aliphatic hydrocarbons are Poly Nuclear Aliphatic Hydrocarbons and organic matter without fused ring and contains hydrogen and carbons invariably with or without substituent attached to it, Total Petroleum Hydrocarbon (TPH) is a term used to describe a large family of several hundred chemical compounds that originally come from crude oil. In this study, Petroleum hydrocarbons such as Petroleum Aliphatic Hydrocarbon (PAHs) and Total petroleum hydrocarbons (TPHs) were analyzed for in the seven sampled aquatic animals using Gas Chromatographic technique. Petroleum Aliphatic Hydrocarbons attained higher concentrations in n-hexadecane, tetracosane and tetradecane with concentration values of 0.49 ± 0.29, 0.59 ± 0.94 and 0.97 ± 0.64 mg/kg respectively. It was found in this study that even chain aliphatic hydrocarbons were found in all the samples and dominated the odd chains aliphatic hydrocarbons. Heavy weight Aliphatic Hydrocarbons like hexacosane and triaconane were not detected in all the tested aquatic animals as Octacosane was found in only three of the aquatic animals while hexatricontane was found in only one of the samples. Odd chain aliphatic hydrocarbons like Nonane and Nonadecane attained their highest concentrations of 0.19 ± 0.15 and 0.33 ± 0.45 mg/kg respectively. It was gathered from the results of this experiment that Total Petroleum Hydrocarbons (TPH) is greater than the aliphatic petroleum hydrocarbons in all the tested aquatic faunas from the Forcados River. TPH and TAH recorded maximum concentrations of 3.64 ± 0.94 and 3.46 ± 0.91 mg/kg respectively