Lipid-derived Compounds Research Articles

Impacts of temperature and fluid seepage on organic matter composition in sediments of an active hydrothermal basin

Marine sediments are one of the largest organic carbon (OC) sinks on Earth. Yet, major knowledge gaps remain in our understanding of sedimentary OC cycling, particularly regarding temperature-induced alteration processes of OC from different sources. Here, we investigate OC-rich sediments of Guaymas Basin (Gulf of California) across two hydrothermal areas, one with only conductive geothermal heating and the other additionally experiencing seepage of hydrocarbon-rich fluids from deeper layers. We use Pyrolysis-Gas Chromatography/Mass Spectrometry (Py-GC/MS) to investigate diagenetic OC changes and show that cold control sites in both hydrothermal areas are dominated by similar contributions of lipid-derived compounds, nitrogenous (likely protein-derived) compounds, carbohydrates, and polyaromatic hydrocarbons (PAHs). These OC compound groups are largely derived from phytoplankton detritus from overlying water. Conductively heated sediments, which reach in situ temperatures of ∼ 80 °C, have similar general OC compositions and contents to these cold sites, but show evidence of diagenetic modifications of individual carbohydrate groups in deeper layers. By contrast, strong decreases in carbohydrate and nitrogenous compound abundances at the seep sites indicate that these compound groups are not only modified but also selectively degraded at the higher temperatures (>80 °C) of these sites. Increases in pyrolysis products of PAHs, prist-1-ene, and alkanes with depth, moreover, show that import of OC by deep hydrothermal fluids contributes significantly to sedimentary OC pools mainly in deeper layers of these sites. Our study provides the first comprehensive analysis of major OC compound groups in Guaymas Basin sediment and indicates that the supply of OC by hydrothermal fluid flow only has minor impacts on particulate organic matter compositions at the seafloor, even at active seep sites. We furthermore show that temperatures up to ∼ 80 °C already result in thermochemical modifications of organic matter (OM) that are potentially linked to the onset of kerogen formation. The sequence and time scales of chemical modifications and activations in relation to temperature are an important subject for future investigations.

Jasmonic acid boosts the salt tolerance of kidney beans (Phaseolus vulgaris L.) by upregulating its osmolytes and antioxidant mechanism.

As a lipid-derived compound, jasmonic acid (JA) regulates growth and defense against environmental stresses. An exogenous foliar JA application was investigated in our study (HA; 0.5 mM) on kidney bean plants (Phaseolus vulgaris L.) grown under different salinity stress concentrations (0, 75, and 150 mM NaCl). According to the results, salt concentrations were related to an increase in malondialdehyde (MDA) levels, whereas they declined the chlorophyll content index. In contrast, JA application decreased the level of MDA but increased the chlorophyll content index. Moreover, increasing salinity levels increased proline, phenolic compounds, flavonoids, free amino acid concentrations, and shikimic acid concentrations, as well as the activities of polyphenol oxidase (PPO), ascorbate peroxidase (APX), catalase (CAT), and peroxidase (POD). In addition, JA applications further increased their concentrations with increasing salinity stress levels. JA application increases salt-induced osmolytes and non-enzymatic antioxidants while increasing enzymatic antioxidant activity, suggesting kidney beans have a strong antioxidant mechanism, which can adapt to salinity stress. Our results showed that exogenous JA foliar applications could enhance the salt tolerance ability of kidney bean plants by upregulating their antioxidant mechanism and osmolytes.

Study of Pansalt® or Laminaria Ochroleuca seaweed powder as potential NaCl replacers in dry-cured foal “cecina”

This study aimed to evaluate the effect of the total or partial replacement of NaCl by a commercial low-salt mixture Pansalt® (T1) or Kombu (L. ochroleuca) seaweed powder (T2), respectively, on the quality properties of dry-cured foal “cecina”. Salt reformulation unaffected fat percentages, decreased (P < 0.001) moisture and ash contents, while protein amounts increased (P < 0.001) in the T2 batch. Considering the physicochemical variables, any significant differences were observed among batches, except for a*, water activity, and springiness values. T1 and T2 samples presented a significant (P < 0.001) sodium decrease of 39% and 48%, respectively, as well as, potassium and magnesium increase (P < 0.001). In addition, the seaweed improved (P < 0.001) calcium, iron, phosphorus, and zinc contents. All batches showed similar lipid profiles and the nutritional indices were in line with the health recommendations. NaCl replacement increased the proteolysis, causing the increment (P < 0.001) of the free amino acids total contents, especially in T2 samples. Changes were also detected in the aromatic profile of our samples, where lipid-derived compounds predominated in the CON batches, while substances originating from carbohydrate fermentation and amino acid breakdown were prevalent in reformulated samples, particularly in T2. In addition, the salting treatments did not affect the sensory profile, except for saltiness (T2). Hence, data indicated that the employ of these potential NaCl alternatives, in particular T2 formulation, represents a favorable approach to achieving equine “cecinas” with an enhanced mineral and healthier profile, without altering most of the sensorial properties.

Inflammation Biomarker Response to Oral 2-Hydroxybenzylamine (2-HOBA) Acetate in Healthy Humans.

Inflammation is associated with the formation of reactive oxygen species (ROS) and the formation of lipid-derived compounds, such as isolevuglandins (IsoLGs), malondialdehyde, 4-hydroxy-nonenal, and 4-oxo-nonenal. The most reactive of these are the IsoLGs, which form covalent adducts with lysine residues and other cellular primary amines leading to changes in protein function, immunogenicity, and epigenetic alterations and have been shown to contribute to a number of inflammatory diseases. 2-Hydroxybenzylamine (2-HOBA) is a natural compound found in buckwheat seeds and reacts with all IsoLG adducts preventing adduct formation with proteins and DNA. Therefore, 2-HOBA is well positioned as an agent for the prevention of inflammatory-prone diseases. In this study, we examined the potential beneficial effects of 2-HOBA on oxidative stress and inflammatory biomarkers in two cohorts of healthy younger and older adults. We utilized the Olink® targeted inflammation panel before and after an oral 15-day treatment regimen with 2-HOBA. We found significant relative changes in the plasma concentration of 15 immune proteins that may reflect the in vivo immune targets of 2-HOBA. Treatment of 2-HOBA resulted in significant increased levels of CCL19, IL-12β, IL-20Rα, and TNFβ, whereas levels of TWEAK significantly decreased. Ingenuity Pathway Analysis identified canonical pathways regulated by the differentially secreted cytokines, chemokines, and growth factors upon 2-HOBA treatment and further points to biofunctions related to the recruitment, attraction, and movement of different immune cell types. In conclusion, 2-HOBA significantly altered the protein biomarkers CCL19, IL-12β, IL-20Rα, TNFβ, and TWEAK, and these may be responsible for the protective effects of 2-HOBA against reactive electrophiles, such as IsoLGs, commonly expressed in conditions of excessive oxidative stress. 2-HOBA has a role as a IsoLG scavenger to proactively improve immune health in a variety of conditions.

Application of thermogravimetric analysis method for the characterisation of products from triglycerides during biodiesel production

In this present work, thermogravimetric analysis (TGA) was used to study the thermal degradation of a range of lipids and lipid-derived compounds associated with the production of biodiesel. Thereafter, the procedure was used to successfully quantify the compounds of three process streams from a biodiesel plant. Relevant organic chemicals involved in biodiesel production chemistry, including glycerol, oleic acid (fatty acid), palmitic acid (fatty acid), rapeseed oil (model triglyceride) and fatty acid methyl esters (FAMES) have been studied to determine their volatilisation/thermal degradation patterns. The developed method was then applied for the quantitative characterisation of three samples from a 3-stage biodiesel production plant, including two in-process samples and the final biodiesel product. The method was able to clearly distinguish between two main sets of compounds namely, early - mid volatiles (glycerol, fatty acids and fatty acid methyl esters) and late volatiles (incompletely converted and unreacted triglycerides). In addition, the FAMES in the industrial samples were extracted into petroleum ether and analysed by gas chromatography - mass spectrometry (GC/MS), with good agreement between the two analytical methods. For instance, GC/MS analysis showed that the three industrial samples contained 31.2 ± 0.1 wt%, 60.6 ± 0.2 wt% and 91 ± 0.53 wt% of FAMES, respectively. Similarly, the TGA method gave the FAMES contents of the three samples as 33.9 ± 0.4 wt%, 57.8 ± 0.2 wt% and 85.3 ± 0.52 wt%. This study shows that TGA is a fast and simple method for accurately monitoring the triglyceride conversion stages and the purity of the final product during biodiesel production, without the need for extensive sample preparations and expensive standard solutions.

Dissolved organic matters with low molecular weight fractions exhibit high photochemical potential for reactive oxygen formation

The photochemical properties of dissolved organic matter (DOM) were highly related to the molecular weight (MW) and organic compositions. In this study, the bulk algae- and macrophyte-derived DOM (ADOM and MDOM, respectively) and Suwannee River humic acid (SRHA) were applied and fractionated into low MW- (LMW, <1 kDa) and high MW-(HMW-, 1 kDã0.45 μm) fractions. The formation and mechanisms of photochemically produced reactive intermediates (e.g., HO•, 1O2, and 3CDOM*) for these bulk and MW-fractionated samples were compared via the irradiation experiment, fluorescence and Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS). Results showed that humic-/fulvic-like substances were mainly distributed in the LMW fraction which occupied about 44–60% of total organic carbon for ADOM and MDOM and 13% for SRHA. Photochemical experiments showed that the autochthonous DOMs (e.g., ADOM and MDOM) were characterized with comparable formation rates and quantum yields of reactive oxygens with the allochthonous SRHA, suggesting the high photochemical formation potential. Further analysis showed obvious MW-dependent heterogeneities that, irrespective of DOM types, the LMW-fraction exhibited higher formation rates and quantum yields, followed by the bulk- and then the HMW-fractions. The fluorescence and FT-ICR-MS results indicated that the unique biochemical classes, i.e., humic-/fulvic-like moieties and protein-/lipid-derived compounds in the LMW fractions may be responsible for the high apparent quantum yields. This study highlighted the importance of simultaneous characterization of MW and organic compositions for evaluating the photochemical potential and other behaviors and effects of aquatic DOMs.

Nɛ-(carboxymethyl)lysine, Available Lysine, and Volatile Compound Profile of Biscuits Enriched with Grape by-Product During Storage.

We investigated the changes in Nɛ-(carboxymethyl)lysine (CML) and available lysine content, antioxidant properties, volatiles, and oxidation products of biscuits enriched with grape by-product (GP), stored for six months under a modified atmosphere of 0%/30%/70% O2/CO2/N2 and in air. Fresh GP-formulated biscuits showed lower concentrations of CML (89%), available lysine (40%), and pyrazines (75%), but higher antioxidant capacities (~ sixfold), furans (12-fold), and lipid-derived compounds (three-fold) than the control. Although ~ 15% higher losses of Maillard-type volatiles were identified in the air atmosphere during storage, lipid oxidation was ~ 30% less pronounced in the modified atmosphere. A significant correlation of 0.994 between the reduction in CML and the available lysine suggest further CML reactions with the ɛ-NH2 group of amino acids. Significant correlations (of -0.550 to -0.980) between oxidation products, antioxidant capacities, and changes in CML content during storage suggest that these parameters might be involved in the CML elimination mechanism.

Effect of Jasmonic Acid Foliar Spray on the Morpho-Physiological Mechanism of Salt Stress Tolerance in Two Soybean Varieties (Glycine max L.).

Jasmonates (JAs) are lipid-derived compounds that function in plants as key signaling compounds during stressful conditions. This study aimed to examine the effects of exogenous fo-liar-JA application (100 μmol L−1) on the morpho-physiological response of two soybean varieties (parachinar-local and swat-84) grown under different NaCl regimes (0, 40, 80, and 120 mM). Results show that exogenous JA application alone and in combination with salt stress altered the growth and metabolism of both soybeans. For instance, they accumulated significant amounts of Na+ and Cl–, while their K+, Mg2+, Fe2+, Mn2+, B3+, and P3+ contents were low. Further, photosynthetic pigments Chl a and Chl b increased at low concentrations of salt and exogenous JA. Car decreased under both salt and exogenous JA as compared with untreated control. In addition, sugar, phenol, and protein content increased under both salt and exogenous JA application. In contrast, the exogenous JA application alleviated the negative impact of salt stress on the growth and metabolism of both soybeans. Further, the high concentrations of soluble protein and phenol in the leaves of both soybeans may contribute to their ability to adapt to salinity. However, molecular studies are necessary to understand the ameliorative role of exogenous JA in the growth and metabolism of salt-treated young seedlings in both soybean varieties.

Development of Beef Volatile Flavor Compounds in Response to Varied Oven Temperature and Degree of Doneness

Beef volatile flavor compound (VFC) development at the center, mid, and surface layers of cooked steaks was evaluated through 18 cookery treatment combinations consisting of oven cooking temperature (OT; 177°C, 246°C, and 343°C) and final internal steak temperature (IT; 57°C, 63°C, 68°C, 74°C, 79°C, and 85°C). In total, 72 VFC were measured representing the Maillard reaction and lipid degradation. Five VFC were impacted by a three-way interaction of OT × IT × layer (P ≤ 0.030). Two VFC were impacted by a two-way interaction of OT × IT (P ≤ 0.010). Sixteen VFC were impacted by a two-way interaction of OT × layer (P ≤ 0.050). Sixteen VFC were impacted by a two-way interaction of IT × layer (P ≤ 0.050). Twenty VFC were impacted by the main effect of layer (P ≤ 0.010). Eight VFC were impacted by the main effect of IT (P ≤ 0.050). Maillard compounds were formed primarily at steak surfaces, with a general increase in content with greater final IT, and OT to a lesser extent. Lipid-derived compounds were diverse. Methyl esters and aldehydes had lower contents at steak surfaces and were primarily found within the inner portions of steaks. Conversely, certain alcohols and ketones were more prominent at steak surfaces. Development of compounds among layers was also consistently influenced by IT and OT. It may be concluded that flavor-contributing compounds vary among cooked beef steaks at different depths and cookery temperatures. As a result, OT and final IT may be utilized to mediate the final volatile compound composition.

Investigating the role of the transcriptional regulator Ure2 on the metabolism of Saccharomyces cerevisiae: a multi-omics approach.

Ure2 regulates nitrogen catabolite repression in Saccharomyces cerevisiae. Deletion of URE2 induces a physiological state mimicking the nitrogen starvation and autophagic responses. Previous work has shown that deletion of URE2 increases the fermentation rate of some wine-producing strains of S. cerevisiae. In this work, we investigated the effect of URE2 deletion (ΔURE2) on the metabolism of S. cerevisiae. During growth on glucose, the ΔURE2 mutant grew at a 40% slower rate than the wild type; however, it produced ethanol at a 31% higher rate. To better under the behavior of this mutant, we performed transcriptomics and metabolomics. Analysis of the RNA sequencing results and metabolite levels indicates that the mutant strain exhibited characteristics of both nitrogen starvation and autophagy, including the upregulation of allantoin, urea, and amino acid uptake and utilization pathways and selective autophagic machinery. In addition, pyruvate decarboxylase and alcohol dehydrogenase isoforms were expressed at higher rates than the wild type. The mutant also accumulated less trehalose and glycogen, and produced more lipids. The induction of a nitrogen starvation-like state and increase in lipid production in nitrogen-rich conditions suggest that URE2 may be a promising target for metabolic engineering in S. cerevisiae and other yeasts for the production of lipids and lipid-derived compounds. KEY POINTS: • Deletion of URE2 increases ethanol and lipid production in Saccharomyces cerevisiae. • Deletion of URE2 reduces glycogen and trehalose production. • Metabolic changes mimic nitrogen starvation and autophagic response.

Impact of layered and delaminated zeolites on catalytic fast pyrolysis of microalgae using fixed-bed reactor and Py-GC/MS

The aim of this work is to exploit the pyrolysis characteristics of microalgae Botryococcus braunii (BB) with a medium pore framework zeolite (MCM-22) and its delaminated counterpart with a higher external surface area zeolite (ITQ-2) using pyrolysis-gas-chromatography-mass-spectrometry (Py-GC/MS) and a fixed-bed reactor. The study evaluates the effect of synthesized zeolites that possess different pore size, shape and acidity on promoting deoxygenation reactions and producing aromatic compounds during the pyrolysis of microalgae. Further, the role of the shape of zeolites (layered & delaminated) for carbohydrate, protein and lipid-derived compounds formation is discussed. The Py-GC/MS results showed that the aromatic compounds (area%) was significantly higher (35.17 %) for delaminated & (28.76 %) for layered zeolites than non-catalytic pyrolysis (17.85 %) at the catalyst/biomass ratio of 10.1. The increase in catalyst/biomass ratio from 3 to 10 at 550 °C has increased the aromatics (90.66 % for ITQ-2 & 75.25 %) for MCM-22 zeolites. In addition, ITQ-2 zeolite produced 20.47 % higher aromatics than MCM-22 zeolites which is attributed to the thinner delaminated structure of ITQ-2 that makes reactants more accessible to the catalytic site and accelerate the deoxygenation reactions.

The Effect of Algae or Insect Supplementation as Alternative Protein Sources on the Volatile Profile of Chicken Meat.

The aim of this study was to investigate the differences in the volatile profile of meat from chickens fed with alternative protein diets (such as algae or insect) through two different trials. In Trial 1, broiler chicken at one day of age were randomly allocated to three experimental groups: a basal control diet (C) and two groups in which the soybean meal was replaced at 75% (in the starter phase) and 50% (in the grower phase) with partially defatted Hermetia illucens (HI) larvae or Arthrospira platensis (SP). In Trial 2, broiler chickens were housed and reared similar to Trial 1, with the exception that the experimental diets replaced soybean meal with either 100% partially defatted HI or 100% SP. In both trials, chickens were slaughtered at day 35. Per group, 10 chickens were submitted to volatile analysis by using solid-phase microextraction (HS-SPME) and gas chromatography–mass spectrometry (GC-MS) analysis. Results in both trials showed that levels of several lipid-derived compounds were found to be lower in chickens fed an HI diet, which could be linked to a possibly lower level of polyunsaturated fatty acid content in HI-fed chicken. In addition, the dietary treatments could be discriminated based on the volatile profile, i.e., the substitution of soy with HI or SP distinctively affected the levels of flavor compounds.

Dietary 18:2n-6 affects EPA (20:5n-3) and ARA (20:4n-6) content in cell membranes and eicosanoid production in Atlantic salmon (Salmo salar L.)

Atlantic salmon (Salmo salar) were fed diets with the three vegetable oils, rapeseed oil (RO), palm oil (PO) and soybean oil (SO), in a mixture design for 12 weeks. The diets contained high levels of monounsaturated fatty acids (mainly 18:1n-9), saturated fatty acids (mainly 16:0) and n-6 fatty acids (mainly 18:2n-6), respectively. The dietary content of 20:4n-6 (arachidonic acid, ARA), 20:5n-3 (eicosapentaenoic acid, EPA) and 22:6n-3 (docosahexaenoic acid, DHA) was similar in all diets. The aim was to investigate how dietary 18:1n-9, 16:0 and 18:2n-6 affect the fatty acid composition of salmon tissues, as well as the lipid metabolism and the fish health through lipid-derived compounds such as eicosanoids. Dietary 18:2n-6 had a clear impact on the fatty acid profile of polar lipids, and caused an increase in ARA levels combined with a concomitant decrease in EPA levels, indicating a direct replacement effect. There was a gradient among the tissues, where the dietary effects were most pronounced in liver polar lipids, followed by heart polar lipids and erythrocytes, while retina and brain were the most conserved. The DHA level in polar lipids was highly conserved. Eicosanoid levels in liver were affected by diets, but did not directly reflect the content of precursor fatty acids in the cell membranes, indicating a more complex relationship. Profiling of the main metabolites of the liver revealed distinct differences between fish fed RO and PO compared to fish fed SO, where the latter had reduced levels of both free carnitine and several acylcarnitines. The accumulation of triacylglycerol in the liver also varied between the diet groups, with the level of dietary saturated fat (16:0) appearing to be the variable in the design explaining most of the variation.

Volatile Compounds of Lamb Longissimus and Semimembranosus from Australia, New Zealand, and the United States

ObjectivesDifferences in production practices based on country of origin create distinct differences in palatability of lamb from both the loin and the leg. The objective of this study was to identify volatile compounds which influence flavor across lamb leg and loin chops sourced from three countries of origin.Materials and MethodsLamb loins (IMPS #232 1 × 1; n = 30/treatment) and legs (IMPS #233A; n = 60/treatment) were sourced from Australia (AUS), New Zealand (NZ), and the United States (US). Product was fabricated to isolate the longissimus lumborum (LL) from the loins and the semimembranosus (SM) with adductor from the legs. Muscles were trimmed of external fat and connective tissue and fabricated into 2.54-cm thick chops, vacuum packaged individually, and frozen. A subset of samples (n = 15/treatment) for volatile compound analysis were thawed at 2–4°C for 24 h, cooked to a medium degree of doneness, frozen, and powdered. Volatile compounds were extracted via SPME from powdered samples and analyzed using GC–MS. Data were analyzed as a 2 × 3 factorial design with muscle, country of origin (COO), and their interaction as fixed effects with a significance level of α = 0.05.ResultsDifferences in volatile compounds of all classes were largely related to COO. Of the 36 lipid-derived compounds, 18 were affected by COO (P &lt; 0.05) and 11 were affected by the interaction of muscle and COO (P &lt; 0.05). Where the interaction was significant, US LL and SM samples generally produced greater concentrations of volatile compounds than other treatments (P &lt; 0.05), especially in compound classes including alcohols, n-aldehydes, and ketones. Of the alkanes evaluated, only pentane was greater in US samples compared to other samples (P &lt; 0.05) and was more than double the concentration produced in NZ and AUS samples. Alkenes did not follow the general trend of being increased in US samples. P-xylene was elevated in SM samples compared to LL samples (P &lt; 0.01), and toluene was greater in NZ samples than US and AUS samples (P &lt; 0.05). D-limonene was decreased in AUS samples compared to US and NZ samples. Of the 18 Maillard-derived compounds identified, 13 were affected by COO (P &lt; 0.05), 3 were affected by muscle (P &lt; 0.01), and 3 were affected by the interaction of COO and muscle (P &lt; 0.05). Of the Strecker aldehydes, 3-methylbutanal and 2-methylbutanal were both affected by both COO (P &lt; 0.01) and muscle (P &lt; 0.05). US samples produced the greatest concentration of these compounds (P &lt; 0.05) and AUS samples produced the least (P &lt; 0.05). Samples from LL produced more of these compounds than SM samples (P &lt; 0.05). Ketones including acetoin and 2,3-butanedione, which contribute positively to flavor in meat, were highly elevated in US samples compared to AUS and NZ (P &lt; 0.05). Sulfur-containing compounds were generally greater in non-domestic product than US samples, except for dimethyl sulfide, which was greatest in US SM samples and least in NZ LL and AUS SM samples (P &lt; 0.05). Pyrazines were generally elevated in NZ samples compared to AUS samples (P &lt; 0.05), with US samples intermediate (P &gt; 0.05).ConclusionCountry of origin is a strong influencer of flavor compounds in lamb. This is likely attributable to global differences in production system including, but not limited to, diet, genetics, sex, and postmortem handling and will influence the perception of flavor by consumers.

Characterisation of the Serum Metabolic Signature of Cholangiocarcinoma in a United Kingdom Cohort

A distinct serum metabonomic pattern has been previously revealed to be associated with various forms of liver disease. Here, we aimed to apply mass spectrometry to obtain serum metabolomic profiles from individuals with cholangiocarcinoma and benign hepatobiliary diseases to gain an insight into pathogenesis and search for potential early-disease biomarkers. Serum samples were profiled using a hydrophilic interaction liquid chromatography platform, coupled to a mass spectrometer. A total of 47 serum specimens from 8 cholangiocarcinoma cases, 20 healthy controls, 8 benign disease controls (bile duct strictures)and 11 patients with hepatocellular carcinoma (as malignant disease controls) were included. Data analysis was performed using univariate and multivariate statistics. The serum metabolome disparities between the metabolite profiles from healthy controls and patients with hepatobiliary disease were predominantly related to changes in lipid and lipid-derived compounds (phospholipids, bile acids and steroids) and amino acid metabolites (phenylalanine). A metabolic pattern indicative of inflammatory response due to cirrhosis and cholestasis was associated with the disease groups. The abundance of phospholipid metabolites was altered in individuals with liver disease, particularly cholangiocarcinoma, but no significant difference was seen between profiles from patients with benign biliary strictures and cholangiocarcinoma. The serum metabolome in cholangiocarcinoma exhibited changes in metabolites related to inflammation, altered energy production and phospholipid metabolism. This study serves to highlight future avenues for biomarker research in large-scale studies.

Palatability of Beef Strip Loin Steaks Following Variable Length High-Concentrate Diet Exposure Prior to Pasture-Finishing

Proximate composition, Warner-Bratzler shear force (WBSF), consumer sensory traits, fatty acid composition, and volatile flavor compounds were assessed on steaks from USDA Select strip loins (n = 40; 8/treatment) representing grass-fed beef sourced from New Zealand (NZ) with marbling consistent with USDA Select along with strip loins from four feeding treatments designed to evaluate the effects of early exposure to grain-based diets for 0 d (0D), 40 d (40D), 80 d (80D), or 120 d (120D) prior to pasture-finishing on meat quality and composition. Percent fat, moisture, and protein and WBSF did not differ (P &gt; 0.05), but percent ash was decreased in 120D samples compared to those from NZ, 0D, and 40D (P &lt; 0.05). Consumer scores for all traits differed among samples from the treatments (P &lt; 0.05), with steaks from NZ receiving greater scores for flavor liking than those from 0D, 40D, and 80D (P &lt; 0.05). Consumers also rated NZ and 120D samples greatest for overall liking (P &lt; 0.05). Saturated fatty acids were decreased, and monounsaturated fatty acids were increased in NZ samples compared to samples from all other treatments (P &lt; 0.05), and conjugated linoleic acid was least in samples from NZ (P &lt; 0.05). The ratio of omega-6 to omega-3 fatty acids was greater in 80D and 120D samples than those from all other treatments (P &lt; 0.05). Non-enzymatic browning-derived ketones and 2-pentylfuran were increased in samples from NZ compared to those from all other treatments (P &lt; 0.05), and differences among treatments in lipid-derived compounds were primarily of alcohols and aldehydes. Early exposure to grain-based diets for 120 d prior to pasture-finishing produces beef that is comparable to grass-fed beef from New Zealand in palatability but differs in chemical composition.

Hydrothermal liquefaction of high- and low-lipid algae: Bio-crude oil chemistry

The bio-crude oil produced from hydrothermal liquefaction (HTL) of a high-protein microalgae useful for wastewater treatment, Galdieria sulphuraria, was comprehensively characterized, and compared to that of a high-lipid microalgae useful for biofuel production, Nannochloropsis salina. HTL was conducted in a batch reactor at temperatures of 310–350°C and reaction times of 5–60min. Characterization methods included high-resolution Fourier transform ion cyclotron resonance mass spectroscopy (FT-ICR MS), fatty acid methyl ester (FAME) analysis by gas chromatography mass spectroscopy (GC/MS), proton nuclear magnetic resonance spectroscopy (1H NMR), and Fourier transform infrared spectroscopy (FT-IR). Milder reaction conditions favored bio-crude oil yield and quality for N. salina, while more severe conditions (350°C) were needed for G. sulphuraria. N. salina-derived bio-crude oil contained mainly C14-C18 fatty acid amides, while G. sulphuraria-derived bio-crude-oil had many N1-3O0-2 hetero-atom compounds. FT-ICR MS showed that the aromaticity of hetero-compounds in N. salina bio-crude oil was higher due to N. salina’s higher carbohydrate content and the tendency of carbohydrate-derived molecules to condense at HTL conditions. FAME-GC/MS and 1H-NMR results showed that stable fatty acid amides increased in G. sulphuraria bio-crude oil at higher temperatures as more protein-derived compounds combined with lipid-derived compounds. While N-containing and high molecular weight compounds are a concern for the upgrading of bio-crude oils obtained from high-protein algal biomass, removal of carbohydrates rather than removal of proteins asa pretreatment to HTL is recommended since carbohydrate-derived compounds are more likely to create highly aromatic hetero-compounds that are much more difficult to upgrade.

Bioactive lipids derived from arachidonic acid metabolism in different types of renal replacement therapy

IntroductionMetabolism and plasma concentration of lipids and lipid-derived compounds play an important role in kidney physiology and pathological processes. The component of membrane phospholipids − arachidonic acid (AA) and its active derivatives − eicosanoids are involved in the development of hypertension, diabetes, inflammation and may contribute to progression of chronic kidney disease (CKD). The purpose of the study was to determine, whether the type of renal replacement therapy has an effect on eicosanoids metabolism. Materials and methodsThe study included 145 patients with CKD: on conservative treatment (n=68), on peritoneal dialysis (PD) (n=23) and undergoing chronic haemodialysis (HD) (n=54). The concentrations of TXB2, 20-HETE, 8-epi-PGF2α in platelet poor plasma (PPP) were determined using the ELISA method and 5-HETE, 12-HETE, 15-HETE were measured using the RP-HPLC. ResultsThe concentrations of TXB2 in HD group, both before (2.28±0.72ng/mL) and after (1.49±0.63ng/mL) haemodialysis treatment differed significantly from PD group (57.76±6.13ng/mL). Haemodialysis session led to the significant decrease in TXB2 plasma concentration (p=0.046). 20-HETE concentrations in HD group (113.55±107.54pg/mL and 199.54±142.98pg/mL before and after haemodialysis, respectively) were significantly higher than in CKD 3–5 group (8.96±12.66pg/mL) and PD group (47.78±34.07pg/mL). The highest concentration of 12-HETE was obtained in PD patients (3.58±3.99ng/mL) and differed significantly from HD group after haemodialysis (0.97±0.28ng/mL) and CKD3-5 group (1.06±0.52ng/mL). The concentrations of 5-HETE, 15-HETE and 8-epi-PGF2α-III did not differ significantly among examined groups. ConclusionsThe concentrations of active AA metabolites depend on the mode of renal replacement therapy and are associated with intensity of oxidative stress. They might be considered as potential indicators of kidney damage.

Metabolic engineering of the oleaginous yeast Rhodosporidium toruloides IFO0880 for lipid overproduction during high-density fermentation.

Natural lipids can be used to make biodiesel and many other value-added compounds. In this work, we explored a number of different metabolic engineering strategies for increasing lipid production in the oleaginous yeast Rhodosporidium toruloides IFO0880. These included increasing the expression of enzymes involved in different aspects of lipid biosynthesis-malic enzyme (ME), pyruvate carboxylase (PYC1), glycerol-3-P dehydrogenase (GPD), and stearoyl-CoA desaturase (SCD)-and deleting the gene PEX10, required for peroxisome biogenesis. Only malic enzyme and stearoyl-CoA desaturase, when overexpressed, were found to significantly increase lipid production. Only stearoyl-CoA desaturase, when overexpressed, further increased lipid production in a strain previously engineered to overexpress acetyl-CoA carboxylase (ACC1) and diacylglycerol acyltransferase (DGA1). Our best strain produced 27.4g/L lipid with an average productivity of 0.31g/L/h during batch growth on glucose and 89.4g/L lipid with an average productivity of 0.61g/L/h during fed-batch growth on glucose. These results further establish R. toruloides as a platform organism for the production of lipids and potentially other lipid-derived compounds from sugars.

Functional Analysis of Jasmonates in Rice through Mutant Approaches.

Jasmonic acid, one of the major plant hormones, is, unlike other hormones, a lipid-derived compound that is synthesized from the fatty acid linolenic acid. It has been studied intensively in many plant species including Arabidopsis thaliana, in which most of the enzymes participating in its biosynthesis were characterized. In the past 15 years, mutants and transgenic plants affected in the jasmonate pathway became available in rice and facilitate studies on the functions of this hormone in an important crop. Those functions are partially conserved compared to other plant species, and include roles in fertility, response to mechanical wounding and defense against herbivores. However, new and surprising functions have also been uncovered by mutant approaches, such as a close link between light perception and the jasmonate pathway. This was not only useful to show a phenomenon that is unique to rice but also helped to establish this role in plant species where such links are less obvious. This review aims to provide an overview of currently available rice mutants and transgenic plants in the jasmonate pathway and highlights some selected roles of jasmonate in this species, such as photomorphogenesis, and abiotic and biotic stress.