Acid Saturation Research Articles

Extracellular Albumin and Endosomal Ions Prime Enterovirus Particles for Uncoating That Can Be Prevented by Fatty Acid Saturation.

There is limited information about the molecular triggers leading to the uncoating of enteroviruses under physiological conditions. Using real-time spectroscopy and sucrose gradients with radioactively labeled virus, we show at 37°C, the formation of albumin-triggered, metastable uncoating intermediate of echovirus 1 without receptor engagement. This conversion was blocked by saturating the albumin with fatty acids. High potassium but low sodium and calcium concentrations, mimicking the endosomal environment, also induced the formation of a metastable uncoating intermediate of echovirus 1. Together, these factors boosted the formation of the uncoating intermediate, and the infectivity of this intermediate was retained, as judged by end-point titration. Cryo-electron microscopy reconstruction of the virions treated with albumin and high potassium, low sodium, and low calcium concentrations resulted in a 3.6-Å resolution model revealing a fenestrated capsid showing 4% expansion and loss of the pocket factor, similarly to altered (A) particles described for other enteroviruses. The dimer interface between VP2 molecules was opened, the VP1 N termini disordered and most likely externalized. The RNA was clearly visible, anchored to the capsid. The results presented here suggest that extracellular albumin, partially saturated with fatty acids, likely leads to the formation of the infectious uncoating intermediate prior to the engagement with the cellular receptor. In addition, changes in mono- and divalent cations, likely occurring in endosomes, promote capsid opening and genome release.IMPORTANCE There is limited information about the uncoating of enteroviruses under physiological conditions. Here, we focused on physiologically relevant factors that likely contribute to opening of echovirus 1 and other B-group enteroviruses. By combining biochemical and structural data, we show that, before entering cells, extracellular albumin is capable of priming the virus into a metastable yet infectious intermediate state. The ionic changes that are suggested to occur in endosomes can further contribute to uncoating and promote genome release, once the viral particle is endocytosed. Importantly, we provide a detailed high-resolution structure of a virion after treatment with albumin and a preset ion composition, showing pocket factor release, capsid expansion, and fenestration and the clearly visible genome still anchored to the capsid. This study provides valuable information about the physiological factors that contribute to the opening of B group enteroviruses.

FadR-Based Biosensor-Assisted Screening for Genes Enhancing Fatty Acyl-CoA Pools in Saccharomyces cerevisiae.

Fatty acid-derived compounds have a range of industrial applications, from chemical building blocks to biofuels. Due to the highly dynamic nature of fatty acid metabolism, it is difficult to identify genes modulating fatty acyl-CoA levels using a rational approach. Metabolite biosensors can be used to screen genes from large-scale libraries in vivo in a high throughput manner. Here, a fatty acyl-CoA sensor based on the transcription factor FadR from Escherichia coli was established in Saccharomyces cerevisiae and combined with a gene overexpression library to screen for genes increasing the fatty acyl-CoA pool. Fluorescence-activated cell sorting, followed by data analysis, identified genes enhancing acyl-CoA levels. From these, overexpression of RTC3, GGA2, and LPP1 resulted in about 80% increased fatty alcohol levels. Changes in fatty acid saturation and chain length distribution could also be observed. These results indicate that the use of this acyl-CoA biosensor combined with a gene overexpression library allows for identification of gene targets improving production of fatty acids and derived products.

Metabolomics: population epidemiology and concordance in Australian children aged 11-12 years and their parents.

ObjectivesNuclear magnetic resonance (NMR) metabolomics is high throughput and cost-effective, with the potential to improve the understanding of disease and risk. We examine the circulating metabolic profile by quantitative NMR metabolomics of a sample of Australian 11–12 year olds children and their parents, describe differences by age and sex, and explore the correlation of metabolites in parent–child dyads.DesignThe population-based cross-sectional Child Health CheckPoint study nested within the Longitudinal Study of Australian Children.SettingBlood samples collected from CheckPoint participants at assessment centres in seven Australian cities and eight regional towns; February 2015–March 2016.Participants1180 children and 1325 parents provided a blood sample and had metabolomics data available. This included 1133 parent–child dyads (518 mother–daughter, 469 mother–son, 68 father–daughter and 78 father–son).Outcome measures228 metabolic measures were obtained for each participant. We focused on 74 biomarkers including amino acid species, lipoprotein subclass measures, lipids, fatty acids, measures related to fatty acid saturation, and composite markers of inflammation and energy homeostasis.ResultsWe identified differences in the concentration of specific metabolites between childhood and adulthood and in metabolic profiles in children and adults by sex. In general, metabolite concentrations were higher in adults than children and sex differences were larger in adults than in children. Positive correlations were observed for the majority of metabolites including isoleucine (CC 0.33, 95% CI 0.27 to 0.38), total cholesterol (CC 0.30, 95% CI 0.24 to 0.35) and omega 6 fatty acids (CC 0.28, 95% CI 0.23 to 0.34) in parent–child comparisons.ConclusionsWe describe the serum metabolite profiles from mid-childhood and adulthood in a population-based sample, together with a parent–child concordance. Differences in profiles by age and sex were observed. These data will be informative for investigation of the childhood origins of adult non-communicable diseases and for comparative studies in other populations.

Saturated Fatty Acids from Dairy Increase Energy Expenditure Following an Acute Meal Challenge (P08-015-19)

ObjectivesEvidence suggests that the amount of fatty acid saturation and chain length affect fatty acid oxidation. Metabolism of unsaturated fatty acids may increase energy expenditure and shorter chain fatty acids may be selectively oxidized more readily. More data are needed to determine the impact of fatty acids, as they exist in dietary fats and oils, upon energy expenditure. We tested differences in energy expenditure after an acute meal challenge prepared with dietary fats and oils with fatty acids of differing chain lengths and saturation. The fats and oils used included olive oil (OO, for oleic acid, 18:1n-9), flaxseed oil (FL, for alpha-linolenic acid, 18:3n-3), sunflower oil (SO, for linoleic acid, 18:2n-6), heavy cream (HC, for saturated fatty acids) and fish oil (FO, for docosahexaenoic acid, 22:6n-3). MethodsHealthy men and women (N = 27; 56% men; age: 26.8 ± 6.8; BMI: 29.1 ± 3.2), participated in a five-way crossover trial with intention to treat analysis. Body composition was assessed prior to the first study visit by dual X-ray absorptiometry. A standard three-day lead-in diet, prescribed for the participants’ energy needs, was consumed prior to testing. Subjects entered the metabolic chamber the evening before testing and were awakened at 6 AM for a resting metabolic rate measurement followed by a four-hour meal challenge. Test days were separated by at least 7 days. A 500 kcal smoothie with 30 g of test fat source was consumed within 15 min of an initial fasting blood draw. Metabolic rate (MR) and oxidation rates for fat, carbohydrate and protein were analyzed with proprietary software (PiLR™; MEI Research, Ltd.) for four hours after the challenge. ResultsMR standardized to fat free mass (FFM) and independent of FFM was greater after HC (1.64 ± 0.24 kcal/min) than FL (1.55 ± 0.26 kcal/min) and OO (1.53 ± 0.24 kcal/min) (P < 0.01) over the 4 hr postprandial period. Over four hours these differences accounted for 21.6 and 26.4 fewer kcal oxidized, respectively. Substrate oxidation rates did not differ between dietary fats. ConclusionsIn contrast to previously reported data, our initial data suggest dairy-derived saturated fatty acids may increase postprandial MR following an acute meal challenge. Funding SourcesThis work was supported by USDA-ARS project 3062-51000-053-00D.

The Divergent Roles of Dietary Saturated and Monounsaturated Fatty Acids on Nerve Function in Murine Models of Obesity.

Neuropathy is the most common complication of prediabetes and diabetes and presents as distal-to-proximal loss of peripheral nerve function in the lower extremities. Neuropathy progression and disease severity in prediabetes and diabetes correlates with dyslipidemia in man and murine models of disease. Dyslipidemia is characterized by elevated levels of circulating saturated fatty acids (SFAs) that associate with the progression of neuropathy. Increased intake of monounsaturated fatty acid (MUFA)-rich diets confers metabolic health benefits; however, the impact of fatty acid saturation in neuropathy is unknown. This study examines the differential effect of SFAs and MUFAs on the development of neuropathy and the molecular mechanisms underlying the progression of the complication. Male mice Mus musculus fed a high-fat diet rich in SFAs developed robust peripheral neuropathy. This neuropathy was completely reversed by switching the mice from the SFA-rich high-fat diet to a MUFA-rich high-fat diet; nerve conduction velocities and intraepidermal nerve fiber density were restored. A MUFA oleate also prevented the impairment of mitochondrial transport and protected mitochondrial membrane potential in cultured sensory neurons treated with mixtures of oleate and the SFA palmitate. Moreover, oleate also preserved intracellular ATP levels, prevented apoptosis induced by palmitate treatment, and promoted lipid droplet formation in sensory neurons, suggesting that lipid droplets protect sensory neurons from lipotoxicity. Together, these results suggest that MUFAs reverse the progression of neuropathy by protecting mitochondrial function and transport through the formation of intracellular lipid droplets in sensory neurons.SIGNIFICANCE STATEMENT There is a global epidemic of prediabetes and diabetes, disorders that represent a continuum of metabolic disturbances in lipid and glucose metabolism. In the United States, 80 million individuals have prediabetes and 30 million have diabetes. Neuropathy is the most common complication of both disorders, carries a high morbidity, and, despite its prevalence, has no treatments. We report that dietary intervention with monounsaturated fatty acids reverses the progression of neuropathy and restores nerve function in high-fat diet-fed murine models of peripheral neuropathy. Furthermore, the addition of the monounsaturated fatty acid oleate to sensory neurons cultured under diabetic conditions shows that oleate prevents impairment of mitochondrial transport and mitochondrial dysfunction through a mechanism involving formation of axonal lipid droplets.

Lime and foliar application of molybdenum affects nodulation, nutrient uptake and pod production in soybean grown in acid soils

Soil acidity is commonly ameliorated with lime while little attention is given to the application of molybdenum which is deficient in acid soils. Molybdenum is an important component of the nitrogenase enzyme essential for the symbiotic nitrogen fixing bacteria. An experiment was conducted in a controlled environment at the University of KwaZulu-Natal to evaluate the effect of lime and molybdenum on nodulation, growth and shoot nutrient content of soybean. The experiment was a randomised complete block design with three rates of lime applied at 0, 2650 and 4280 kg ha-1 and molybdenum as ammonium molybdate at 0 and 0.5 g L-1. Lime significantly (p&lt;0.01) increased the uptake of Ca and P but decreased that of Mn. Also, increasing lime levels positively influenced most of the important plant growth parameters measured in the study. Molybdenum application significantly increased nodule formation but did not influence the concentration and uptake of the nutrients measured. Lime application also improved soil Ca and Mg but reduced Mn and exchangeable acidity levels at the end of the study. The treatment combination of lime at 4280 kg ha-1 and ammonium molybdate at 0.5 g L-1 gave the best result in nearly all parameters tested and it can hence be concluded that this combination improves both the nutrient uptake and nodulation of soybean grown in soil with very high acid saturation.

The Reactions of Common Chemical Fertilizers in An Ultisol and Their Effects on Cowpea Performance

Chemical fertilizers (CF) are the major input on arable farms in Nigeria. Current increasing rate of nutrient depletion in CF treated soils calls for the need to study their reactions in soils. To achieve this, three CF based treatments, namely NPK 15:15:15 applied at 40 kg P2O5 ha-1, Urea applied at 20 kg N ha-1 mixed with Single superphosphate at 40 kg P2O5 ha-1, and single superphosphate at 40 kg P2O5 ha-1 mixed with Gliricidia sepium leaves at 20 kg N ha-1 were studied. Sole lime (CaCO3) at 1 Mg ha-1 and a plot that received no amendment were compared. Cowpea was grown for two consecutive cropping seasons in 2012 and 2013 on the treated fields. The results indicated that CF reduced soil pH from initial 4.8 to 4.0. The NPK 15:15:15 fertilizer was the most severe of the CF tested, removing up to 133% alkalinity from the soil relative to lime. The NPK 15:15:15 reduced calcium saturation (from 25% to 21%) and magnesium saturation (from 12% to 8.3%) and increased acidity saturation (from 53% to 66%) with significant reductions in organic carbon content (from 13.2 g kg-1 to 11.0 g kg-1). Precaution including co-application of CF with organic materials such as Gliricidia sepium leaves can benefit for the soils.

Fatty Acid Profiling of Polyethylene Glycol Adapted and Un-Adapted Cell Lines of &amp;lt;i&amp;gt;Oryza sativa&amp;lt;/i&amp;gt; L.cv. Swat-1 under Temperature Stress

Higher plants can adapt to abiotic stress to a certain degree. In this study, the impact of temperature stress on osmotic stress adapted and un-adapted cell lines of rice (Oryza sativa L.cv Swat-1) was observed. For the change in proline content, relative growth rate, saturated and unsaturated fatty acid were evaluated. The cell lines were incrementally adapted to 20% polyethylene glycol. The adapted lines showed significantly higher growth rate and proline content as compared to the un-adapted cell lines on temperature stress. Among saturated fatty acids palmitic acid (C16:0), stearic acid (C18:0) and myristic acid (C14:0) were the prominent fatty acids detected while among unsaturated fatty acid Oleic acid (C18:1c) and Linoleic acid (C18:2c) were the major fatty acids found. Under low temperature stress the percentage of saturated fatty acids was found to be lower (53%) in adapted cell line as compared to the un-adapted cell line (63%) while the percentage of saturation increased (83%) in adapted line under high temperature stress as compared to un-adapted line (70%). On the other hand at low temperature stress the percent level of unsaturated fatty acids in the adapted line was higher (48%) than the un-adapted cell line (37%). In conclusion, adaptation to one abiotic stress confers co-tolerance to the other abiotic stresses. Fatty acids saturation level could be a crucial factor in the plant ability to tolerate heat and cold stress.

Serum albumin-fatty acid saturation test

Circulating non-esterified fatty acids (NEFA) are toxic to mammalian cells. They increase in diseases such as diabetes and sepsis. Herein we propose a serum albumin-fatty acid saturation test.•We based our test on three methodologies: isoelectric focusing (IF) of human plasma albumin, staining proteins after isoelectric focusing in gels with Coomassie Brilliant Blue, and serum albumin measurement with bromocresol green.•The test consists in the determination of albumin IF and staining with bromocresol green. If albumin is saturated with NEFA, it focuses on lower pH, meaning it is the threshold to bind to them. Excessive NEFA is free and toxic. Many other tests are available for NEFA quantification as NEFA kit assay. All colorimetric assays are used for quantification of NEFA and other tests need expensive equipment to read out the results, and they do not measure albumin levels.•Our method focused on albumin-NEFA saturation instead of just NEFA quantification. Critically ill patients have an alteration in both albumin and NEFA. Therefore, our test undergoes less daytime variation compared to assays that measure absolute NEFA values, allowing a more reliable use as an indicator of albumin-fatty acid saturation and NEFA toxicity.

Modification of sperm fatty acid composition during epididymal maturation in bats.

Biochemical properties of polyunsaturated fatty acids (PUFAs) are fundamental to sperm movements. Amongst all adjustments operated during epididymal maturation, sperm membrane lipid composition is remodelled. Specifically, the proportion of PUFAs usually increases from the caput towards the cauda epididymidis. In mammals, PUFAs are predominantly acquired through the diet, which can consequently impact male fertility. We aimed at analysing to what extent n-6 and n-3 PUFAs are incorporated into sperm in the Seba's short-tailed bat (Carollia perspicillata), and at demonstrating the effect of the sperm fatty acid composition on sperm mobility. We therefore provided food varying in fatty acid composition to males of C. perspicillata and measured the fatty acid composition and mobility traits in spermatozoa collected from the caput and cauda epididymides. We found that n-6 and n-3 PUFAs and saturated fatty acids were significantly related to sperm velocity but not to the proportion of progressive sperm (i.e. motility). Concomitant to an increase in sperm velocity, the level of fatty acid saturation increased from the caput to the cauda epididymidis, while the proportion of PUFAs remained similar along the epididymis. A reduction in n-6 PUFAs counterbalanced an increase in n-3 PUFAs. The food treatments did not affect the sperm fatty acid composition. Our results suggest that a precise endogenous control rather than dietary effects determines sperm fatty acid composition in C. perspicillata.

Palmitate- and C6 ceramide-induced Tnnt3 pre-mRNA alternative splicing occurs in a PP2A dependent manner

BackgroundIn a previous study, we showed that consumption of diets enriched in saturated fatty acids causes changes in alternative splicing of pre-mRNAs encoding a number of proteins in rat skeletal muscle, including the one encoding skeletal muscle Troponin T (Tnnt3). However, whether saturated fatty acids act directly on muscle cells to modulate alternative pre-mRNA splicing was not assessed. Moreover, the signaling pathway through which saturated fatty acids act to promote changes in alternative splicing is unknown. Therefore, the objective of the present study was to characterize the signaling pathway through which saturated fatty acids act to modulate Tnnt3 alternative splicing.MethodsThe effects of treatment of L6 myotubes with saturated (palmitate), mono- (oleate), or polyunsaturated (linoleate) fatty acids on alternative splicing of pre-mRNA was assessed using Tnnt3 as a marker gene.ResultsPalmitate treatment caused a two-fold change (p < 0.05) in L6 myotube Tnnt3 alternative splicing whereas treatment with either oleate or linoleate had minimal effects compared to control myotubes. Treatment with a downstream metabolite of palmitate, ceramide, had effects similar to palmitate on Tnnt3 alternative splicing and inhibition of de novo ceramide biosynthesis blocked the palmitate-induced alternative splicing changes. The effects of palmitate and ceramide on Tnnt3 alternative splicing were accompanied by a 40–50% reduction in phosphorylation of Akt on S473. However, inhibition of de novo ceramide biosynthesis did not prevent palmitate-induced Akt dephosphorylation, suggesting that palmitate may act in an Akt-independent manner to modulate Tnnt3 alternative splicing. Instead, pre-treatment with okadaic acid at concentrations that selectively inhibit protein phosphatase 2A (PP2A) blocked both palmitate- and ceramide-induced changes in Tnnt3 alternative splicing, suggesting that palmitate and ceramide act through PP2A to modulate Tnnt3 alternative splicing.ConclusionsOverall, the data show that fatty acid saturation level and ceramides are important factors modulating alternative pre-mRNA splicing through activation of PP2A.

Metabolic and physiological regulation of Chlorella sp. (Trebouxiophyceae, Chlorophyta) under nitrogen deprivation

A freshwater green microalgae Chlorella sp., UMACC344 was shown to produce high lipid content and has the potential to be used as feedstock for biofuel production. In this study, photosynthetic efficiency, biochemical profiles and non-targeted metabolic profiling were studied to compare between the nitrogen-replete and deplete conditions. Slowed growth, change in photosynthetic pigments and lowered photosynthetic efficiency were observed in response to nitrogen deprivation. Biochemical profiles of the cultures showed an increased level of carbohydrate, lipids and total fatty acids, while the total soluble protein content was lowered. A trend of fatty acid saturation was observed in the nitrogen-deplete culture with an increase in the level of saturated fatty acids especially C16:0 and C18:0, accompanied by a decrease in proportions of monounsaturated and polyunsaturated fatty acids. Fifty-nine metabolites, including amino acids, lipids, phytochemical compounds, vitamins and cofactors were significantly dysregulated and annotated in this study. Pathway mapping analysis revealed a rewiring of metabolic pathways in the cells, particularly purine, carotenoid, nicotinate and nicotinamide, and amino acid metabolisms. Within the treatment period of nitrogen deprivation, the key processes involved were reshuffling of nitrogen from proteins and photosynthetic machinery, together with carbon repartitioning in carbohydrates and lipids.

8 - Supplementation with omega-3 fatty acids potentiates glutathione oxidation in human airway epithelial cells exposed to ozone

The health benefits of dietary fish oil consumption have been widely reported. Eicosapentaenoic (EPA) and docosahexaenoic (DHA) acids, two omega-3 fatty acids found in fish oil, have been associated with anti-inflammatory and pro-resolving effects through their metabolism to specialized pro-resolving mediators (SPMs) and displacement of arachidonic acid (AA). However, the 5 and 6 double bonds in EPA and DHA respectively are targets for lipid peroxidation by ozone (O3), a major photochemical pollutant to which millions of Americans are exposed. Products of unsaturated fatty acid peroxidation by O3 have been proposed to mediate functional and inflammatory effects of O3 exposure. Thus, cellular supplementation with omega-3s has the potential to both promote and help resolve inflammation during O3 exposure. To investigate this paradox, we supplemented 16-HBE human airway epithelial cells (HAEC) expressing the fluorogenic glutathione redox potential (EGSH) sensor roGFP overnight with EPA, DHA, the monounsaturated fatty acid oleic acid (OA), or the saturated fatty acid stearic acid (SA). Alterations in EGSH were monitored in real time using live-cell microscopy during exposure to O3. We found that supplementation with EPA and DHA, but not OA or SA, caused a marked potentiation of the O3-induced increases in EGSH, evident as both an accelerated response time and increase in the magnitude of response. Notably, the potentiation of GSH oxidation occurred at O3 concentrations as low as 0.08 ppm, the current National Ambient Air Quality Standard level. These results suggest that membrane fatty acid saturation is a determinant of the oxidative responses to O3 in HAEC. These findings may have implications for dietary recommendations for populations exposed to O3. This abstract does not necessarily reflect EPA policy.

Allelochemicals from Alexandrium minutum induce rapid inhibition of metabolism and modify the membranes from Chaetoceros muelleri

Allelochemical interactions are likely to be a contributing factor explaining the success of large blooms of the harmful marine dinoflagellate Alexandrium, however, the physiological mechanisms of allelochemical interactions remain poorly described. Here we investigated the sub-lethal effects (on an hourly scale) of a filtrate containing allelochemicals from Alexandrium minutum on the physiology of the common diatom Chaetoceros muelleri. The filtrate induced deleterious effects to the diatom physiology within only 30 min of exposure. Esterase activity and photosynthesis were drastically inhibited, with up to 34% of the population being metabolically inactive and up to 30% reduction in photosystem II quantum yield when exposed to the filtrate. In addition, intracellular reactive oxygen species increased by 26% in response to allelochemical exposure. C. muelleri pigment and lipid analyses indicated that the photosystem II was inhibited, with photoinhibition-like responses (activation of xanthophyll cycles, and changes in associated lipids) upregulated to mitigate the toxic effects of allelochemicals. Changes in the proportions of membrane lipid classes and increased membrane fatty acids saturation by 9% may be an attempt to maintain membrane integrity and associated enzyme activity, or could be the result of deleterious effects on membranes. An 8% decrease in cellular storage lipids (triglycerides) revealed a mobilization of energy suggesting an energetic cost for the diatom to counteract the allelochemical effects. We hypothesize that the rapid alteration of physiological functions such as photosynthesis and some enzymatic activities may result from direct damage on external membranes. Overall this study describes the sub-lethal mechanisms and provides useful biomarkers to understand the role of allelochemical interactions and associated ecological processes in structuring plankton communities.

Triglycerides Promote Lipid Homeostasis during Hypoxic Stress by Balancing Fatty Acid Saturation

SummaryLipid droplets, which store triglycerides and cholesterol esters, are a prominent feature of clear cell renal cell carcinoma (ccRCC). Although their presence in ccRCC is critical for sustained tumorigenesis, their contribution to lipid homeostasis and tumor cell viability is incompletely understood. Here we show that disrupting triglyceride synthesis compromises the growth of both ccRCC tumors and ccRCC cells exposed to tumor-like conditions. Functionally, hypoxia leads to increased fatty acid saturation through inhibition of the oxygen-dependent stearoyl-CoA desaturase (SCD) enzyme. Triglycerides counter a toxic buildup of saturated lipids, primarily by releasing the unsaturated fatty acid oleate (the principal product of SCD activity) from lipid droplets into phospholipid pools. Disrupting this process derails lipid homeostasis, causing overproduction of toxic saturated ceramides and acyl-carnitines as well as activation of the NF-κB transcription factor. Our work demonstrates that triglycerides promote homeostasis by “buffering” specific fatty acids.

Thermal niche evolution of functional traits in a tropical marine phototroph.

Land-based plants and ocean-dwelling microbial phototrophs known as phytoplankton, are together responsible for almost all global primary production. Habitat warming associated with anthropogenic climate change has detrimentally impacted marine primary production, with the effects observed on regional and global scales. In contrast to slower-growing higher plants, there is considerable potential for phytoplankton to evolve rapidly with changing environmental conditions. The energetic constraints associated with adaptation in phytoplankton are not yet understood, but are central to forecasting how global biogeochemical cycles respond to contemporary ocean change. Here, we demonstrate a number of potential trade-offs associated with high-temperature adaptation in a tropical microbial eukaryote, Amphidinium massartii (dinoflagellate). Most notably, the population became high-temperature specialized (higher fitness within a narrower thermal envelope and higher thermal optimum), and had a greater nutrient requirement for carbon, nitrogen and phosphorus. Evidently, the energetic constraints associated with living at elevated temperature alter competiveness along other environmental gradients. While high-temperature adaptation led to an irreversible change in biochemical composition (i.e., an increase in fatty acid saturation), the mechanisms underpinning thermal evolution in phytoplankton remain unclear, and will be crucial to understanding whether the trade-offs observed here are species-specific or are representative of the evolutionary constraints in all phytoplankton.

Altered plasmalogen content and fatty acid saturation following epithelial to mesenchymal transition in breast epithelial cell lines

Epithelial to mesenchymal transition (EMT) is a developmental event characterized by phenotypic switching from a polarized epithelial phenotype to an unpolarized mesenchymal phenotype. Changes to plasma membrane function accompany EMT yet the differences in lipid composition of cells that have undergone EMT are relatively unexplored. To address this the lipidome of two cell models of EMT in breast epithelial tissue, D492 and HMLE, were analyzed by untargeted LC-MS. Detected masses were identified and their abundance was compared through multivariate statistical analysis. Considerable concordance was observed in eight lipid components between epithelial and mesenchymal cells in both cell models. Specifically, an increase in phosphatidylcholine and triacylglycerol were found to accompany EMT while phosphatidylcholine- and phosphatidylethanolamine plasmalogens, as well as diacylglycerols decreased. The most abundant fatty acid lengths were C16 and C18 but mesenchymal cells had on average shorter and more unsaturated fatty acids. The results are consistent with enhanced cell mobility post EMT and reflect a consequence of oxidative stress pre- and post EMT in breast epithelial tissue.

From Catalyst Layer to Flow Field: Analysis of Electrolyte Redistribution in HT-PEFC By Operando X-Ray Tomographic Microscopy

High temperature polymer electrolyte fuel cells are based on a polybenzimidazole membrane, imbibed with phosphoric acid as the electrolyte. Phosphoric acid shows a high degree of mobility within the membrane and, as was shown by Eberhardt et.al [1], can also invade the pores of the anode gas diffusion layer (GDL) after a current step from 0.2 Acm2 to 0.8 Acm2 and even invade the channel of the flow field, where it is removed from the fuel cell. The loss of electrolyte is a mayor degradation mode of HT-PEFCs and may also affect the performance of a HT-PEFC. In recent years, synchrotron based operando x-ray tomographic microscopy of HT-PEFCs has been applied for visualizing and quantifying phosphoric acid redistribution in the GDL [1]. In the present work, this technique was used to quantify phosphoric acid saturation in the anode GDL after a current step (s. figure 1) and correlated it with operando electrochemical impedance spectroscopy measurement. The synchrotron imaging parameters were optimized to enable the quantification of the acid redistribution in the GDL, the microporous layer and the catalyst layer. For the first time, phosphoric acid redistribution in the cracks of both, microporous and catalyst layers, was evaluated and quantified, allowing the determination of flooding time constants for the cracks in both layers. The redistribution of acid in both, anode and cathode catalyst layers, is quantified and compared.

The Impact of Aging, Calorie Restriction and Dietary Fat on Autophagy Markers and Mitochondrial Ultrastructure and Dynamics in Mouse Skeletal Muscle.

Loss of skeletal muscle mass and function is a hallmark of aging. This phenomenon has been related to a dysregulation of mitochondrial function and proteostasis. Calorie restriction (CR) has been demonstrated to delay aging and preserve function until late in life, particularly in muscle. Recently, we reported the type of dietary fat plays an important role in determining life span extension with 40% CR in male mice. In these conditions, lard fed mice showed an increased longevity compared to mice fed soybean or fish oils. In this article, we analyze the effect of 40% CR on muscle mitochondrial mass, autophagy, and mitochondrial dynamics markers in mice fed these diets. In CR fed animals, lard preserved muscle fibers structure, mitochondrial ultrastructure, and fission/fusion dynamics and autophagy, not only compared to control animals, but also compared with CR mice fed soybean and fish oils as dietary fat. We focus our discussion on dietary fatty acid saturation degree as an essential predictor of life span extension in CR mice.

The variability of cottonseed yield under different potassium levels is associated with the changed oil metabolism in embryo

Although the effects of potassium (K) fertilizer on cottonseed yield have been explored, reports on cottonseed yield components and related oil metabolism in genotypes differing in sensitivity to low K are limited. To this end, the cultivars Simian 3 (low K-tolerant) and Siza 3 (low K-sensitive) were grown in 2012 and 2013 under three K2O rates (0, 150 and 300 kg ha−1). Results indicated that K application treatments (150 and 300 kg K2O ha−1) increased seedcotton yield, oil yield, protein yield, seed weight boll‐1 and individual seed weight. Higher individual seed weight as the most basic cottonseed yield component was attributed to the enhanced oil weight seed−1 rather than protein weight seed−1 at higher K application rates. Higher oil weight seed−1 in the K application treatments than the 0 kg K2O ha−1 treatment was a consequence of differences in oil accumulation dynamics. Additionally, higher rates of oil accumulation in the K application treatments were closely associated with phosphatidic acid phosphatase and glucose-6-phosphate dehydrogenase activities. Fatty acid composition was also altered by K treatment, where the percentage of palmitic and tetradecanoic acids decreased and linoleic acid percentage increased with K application, leading to a higher ratio of total unsaturated fatty acids to total saturated fatty acids. Furthermore, the magnitudes of increases in seedcotton yield and individual seed weight with K application were greater in the low-K sensitive cultivar than the low-K tolerant one. K application influenced oil accumulation dynamics and fatty acid saturation levels to a greater extent in the low-K sensitive cultivar than the low-K tolerant cultivar. In conclusion, K application could positively influence cottonseed yield by increasing oil accumulation in individual seed and positively improve the unsaturated fatty acid percentage of cottonseed oil.