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• Green solvent extraction techniques reviewed for antibiotic residue analysis. • Food and environmental water sample matrices discussed. • Comparison of different extraction, chromatographic and detection techniques for antibiotics. Antibiotic residues are being continuously recognized in the aquatic environment and in food. Though the concentration of antibiotic residues is typically low, adverse effects on the environment and human health have been observed. Hence, an efficient method to determine numerous antibiotic residues should be simple, inexpensive, selective, with high throughput and with low detection limits. Liquid-based extractions have been exceedingly used for clean-up and preconcentration of antibiotics prior to chromatographic analysis. In order to make methods more green and environmentally sustainable, conventional hazardous organic solvents can be replaced with green solvents. This review presents sampling strategies as well as comprehensive and up-to-date methods for chemical analysis of antibiotic residues in different sample matrices. Particularly, solvent-based sample preparation techniques using green solvents are discussed along with applications in antibiotic residue analysis. [ABSTRACT FROM AUTHOR]

Examines the use of polymer nanoparticles as pseudostationary phase in capillary electrochromatography with electrospray ionization mass spectrometry. Interaction between analytes and nanoparticles; Efficacy of capillary electrochromatography; Combination of the efficiency of capillary electrophoresis with the selectivity of liquid chromatography.

Introduction: Diet stands as a pivotal modifiable risk factor influencing weight gain and the onset of type-2 diabetes (T2D). This study delves into the variation in glucose and regulatory pancreatic hormone levels subsequent to the consumption of meals with differing macronutrient compositions., Methods: The cohort comprised 20 individuals diagnosed with T2D and 21 without diabetes. Participants underwent a cross-over design, consuming four isocaloric meals (600 kcal) enriched in carbohydrate, fiber, fat and protein. Plasma glucose, insulin and glucagon levels were measured at -30, and -5 min, followed by subsequent measurements every 30 min for 240 min post meal intake. Quantification of alterations in the postprandial state was accomplished through the incremental area under the curve (iAUC) and the incremental peak height for the insulin:glucagon ratio (IGR) and plasma glucose levels. The meal demonstrating the lowest responses across these variables was deemed the optimal meal., Results: Meals rich in protein and fat, and consequently low in carbohydrate, exhibited reduced incremental peak and iAUC for both glucose and the IGR in comparison to the other meals. While the protein-enriched meal neared optimal standards, it proved less efficient for individuals without T2D and possessing a low BMI, as well as in those with T2D and poor glycemic control., Conclusion: Our findings endorse the adoption of protein-enriched, low-carbohydrate meals to curtail the meal-induced anabolic hormonal response while averting excessive fluctuations in glucose levels., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Ekberg, Catrina and Spégel.)

The chemical and biological conversion of biomass-derived lignin is a promising pathway for producing valuable low molecular weight aromatic chemicals, such as vanillin or guaiacol, known as lignin monomers (LMs). Various methods employing chromatography and electrospray ionization-mass spectrometry (ESI-MS) have been developed for LM analysis, but the impact of LM chemical properties on analytical performance remains unclear. This study systematically optimized ESI efficiency for 24 selected LMs, categorized by functionality. Fractional factorial designs were employed for each LM to assess ESI parameter effects on ionization efficiency using ultra-high-performance supercritical fluid chromatography/ESI-MS (UHPSFC/ESI-MS). Molecular descriptors were also investigated to explain variations in ESI parameter responses and chromatographic retention among the LMs. Structural differences among LMs led to complex optimal ESI settings. Notably, LMs with two methoxy groups benefited from higher gas and sheath gas temperatures, likely due to their lower log P and higher desolvation energy requirements. Similarly, vinyl acids and ketones showed advantages at elevated gas temperatures. The retention in UHPSFC using a diol stationary phase was correlated with the number of hydrogen bond donors. In summary, this study elucidates structural features influencing chromatographic retention and ESI efficiency in LMs. The findings can aid in developing analytical methods for specific technical lignins. However, the absence of an adequate number of LM standards limits the prediction of LM structures solely based on ESI performance data., (© 2024. The Author(s).)

Hormone-sensitive lipase (HSL) is active throughout the brain and its genetic ablation impacts brain function. Its activity in the brain was proposed to regulate bioactive lipid availability, namely eicosanoids that are inflammatory mediators and regulate cerebral blood flow (CBF). We aimed at testing whether HSL deletion increases susceptibility to neuroinflammation and impaired brain perfusion upon diet-induced obesity. HSL-/-, HSL+/-, and HSL+/+ mice of either sex were fed high-fat diet (HFD) or control diet for 8 weeks, and then assessed in behavior tests (object recognition, open field, and elevated plus maze), metabolic tests (insulin and glucose tolerance tests and indirect calorimetry in metabolic cages), and CBF determination by arterial spin labeling (ASL) magnetic resonance imaging (MRI). Immunofluorescence microscopy was used to determine coverage of blood vessels, and morphology of astrocytes and microglia in brain slices. HSL deletion reduced CBF, most prominently in cortex and hippocampus, while HFD feeding only lowered CBF in the hippocampus of wild-type mice. CBF was positively correlated with lectin-stained vessel density. HSL deletion did not exacerbate HFD-induced microgliosis in the hippocampus and hypothalamus. HSL-/- mice showed preserved memory performance when compared to wild-type mice, and HSL deletion did not significantly aggravate HFD-induced memory impairment in object recognition tests. In contrast, HSL deletion conferred protection against HFD-induced obesity, glucose intolerance, and insulin resistance. Altogether, this study points to distinct roles of HSL in periphery and brain during diet-induced obesity. While HSL-/- mice were protected against metabolic syndrome development, HSL deletion reduced brain perfusion without leading to aggravated HFD-induced neuroinflammation and memory dysfunction., (© 2024 The Authors. Journal of Neurochemistry published by John Wiley & Sons Ltd on behalf of International Society for Neurochemistry.)

Aquaglyceroporin 7 (AQP7) facilitates glycerol flux across the plasma membrane with a critical physiological role linked to metabolism, obesity, and associated diseases. Here, we present the single-particle cryo-EM structure of AQP7 determined at 2.55 Å resolution adopting two adhering tetramers, stabilized by extracellularly exposed loops, in a configuration like that of the well-characterized interaction of AQP0 tetramers. The central pore, in-between the four monomers, displays well-defined densities restricted by two leucine filters. Gas chromatography mass spectrometry (GC/MS) results show that the AQP7 sample contains glycerol 3-phosphate (Gro3P), which is compatible with the identified features in the central pore. AQP7 is shown to be highly expressed in human pancreatic α- and β- cells suggesting that the identified AQP7 octamer assembly, in addition to its function as glycerol channel, may serve as junction proteins within the endocrine pancreas., (© 2023. The Author(s).)

Background: Despite decades of engineering efforts, recombinant Saccharomyces cerevisiae are still less efficient at converting D-xylose sugar to ethanol compared to the preferred sugar D-glucose. Using GFP-based biosensors reporting for the three main sugar sensing routes, we recently demonstrated that the sensing response to high concentrations of D-xylose is similar to the response seen on low concentrations of D-glucose. The formation of glycolytic intermediates was hypothesized to be a potential cause of this sensing response. In order to investigate this, glycolysis was disrupted via the deletion of the phosphoglucose isomerase gene (PGI1) while intracellular sugar phosphate levels were monitored using a targeted metabolomic approach. Furthermore, the sugar sensing of the PGI1 deletants was compared to the PGI1-wildtype strains in the presence of various types and combinations of sugars., Results: Metabolomic analysis revealed systemic changes in intracellular sugar phosphate levels after deletion of PGI1, with the expected accumulation of intermediates upstream of the Pgi1p reaction on D-glucose and downstream intermediates on D-xylose. Moreover, the analysis revealed a preferential formation of D-fructose-6-phosphate from D-xylose, as opposed to the accumulation of D-fructose-1,6-bisphosphate that is normally observed when PGI1 deletants are incubated on D-fructose. This may indicate a role of PFK27 in D-xylose sensing and utilization. Overall, the sensing response was different for the PGI1 deletants, and responses to sugars that enter the glycolysis upstream of Pgi1p (D-glucose and D-galactose) were more affected than the response to those entering downstream of the reaction (D-fructose and D-xylose). Furthermore, the simultaneous exposure to sugars that entered upstream and downstream of Pgi1p (D-glucose with D-fructose, or D-glucose with D-xylose) resulted in apparent synergetic activation and deactivation of the Snf3p/Rgt2p and cAMP/PKA pathways, respectively., Conclusions: Overall, the sensing assays indicated that the previously observed D-xylose response stems from the formation of downstream metabolic intermediates. Furthermore, our results indicate that the metabolic node around Pgi1p and the level of D-fructose-6-phosphate could represent attractive engineering targets for improved D-xylose utilization., (© 2022. The Author(s).)

Objective: Ependymin-Related Protein 1 (EPDR1) was recently identified as a secreted human batokine regulating mitochondrial respiration linked to thermogenesis in brown fat. Despite that EPDR1 is expressed in human pancreatic β-cells and that glucose-stimulated mitochondrial metabolism is critical for stimulus-secretion coupling in β-cells, the role of EPDR1 in β-cell metabolism and function has not been investigated., Methods: EPDR1 mRNA levels in human pancreatic islets from non-diabetic (ND) and type 2 diabetes (T2D) subjects were assessed. Human islets, EndoC-βH1 and INS1 832/13 cells were transfected with scramble (control) and EPDR1 siRNAs (EPDR1-KD) or treated with human EPDR1 protein, and glucose-stimulated insulin secretion (GSIS) assessed by ELISA. Mitochondrial metabolism was investigated by extracellular flux analyzer, confocal microscopy and mass spectrometry-based metabolomics analysis., Results: EPDR1 mRNA expression was upregulated in human islets from T2D and obese donors and positively correlated to BMI of donors. In T2D donors, EPDR1 mRNA levels negatively correlated with HbA1c and positively correlated with GSIS. EPDR1 silencing in human islets and β-cell lines reduced GSIS whereas treatment with human EPDR1 protein increased GSIS. Epdr1 silencing in INS1 832/13 cells reduced glucose- and pyruvate- but not K + -stimulated insulin secretion. Metabolomics analysis in Epdr1-KD INS1 832/13 cells suggests diversion of glucose-derived pyruvate to lactate production and decreased malate-aspartate shuttle and the tricarboxylic acid (TCA) cycle activity. The glucose-stimulated rise in mitochondrial respiration and ATP/ADP-ratio was impaired in Epdr1-deficient cells., Conclusion: These results suggests that to maintain glucose homeostasis in obese people, upregulation of EPDR1 may improve β-cell function via channelling glycolysis-derived pyruvate to the mitochondrial TCA cycle., (Copyright © 2022 The Author(s). Published by Elsevier GmbH.. All rights reserved.)

Cultivated oat (Avena sativa L.) is an allohexaploid (AACCDD, 2n = 6x = 42) thought to have been domesticated more than 3,000 years ago while growing as a weed in wheat, emmer and barley fields in Anatolia 1,2 . Oat has a low carbon footprint, substantial health benefits and the potential to replace animal-based food products. However, the lack of a fully annotated reference genome has hampered efforts to deconvolute its complex evolutionary history and functional gene dynamics. Here we present a high-quality reference genome of A. sativa and close relatives of its diploid (Avena longiglumis, AA, 2n = 14) and tetraploid (Avena insularis, CCDD, 2n = 4x = 28) progenitors. We reveal the mosaic structure of the oat genome, trace large-scale genomic reorganizations in the polyploidization history of oat and illustrate a breeding barrier associated with the genome architecture of oat. We showcase detailed analyses of gene families implicated in human health and nutrition, which adds to the evidence supporting oat safety in gluten-free diets, and we perform mapping-by-sequencing of an agronomic trait related to water-use efficiency. This resource for the Avena genus will help to leverage knowledge from other cereal genomes, improve understanding of basic oat biology and accelerate genomics-assisted breeding and reanalysis of quantitative trait studies., (© 2022. The Author(s).)

Aims: The population of immigrants from the Middle East in Sweden show a higher prevalence of type 2 diabetes (T2D) compared to native Swedes. The exact reason for this is unknown. Here, we have performed metabolite profiling to investigate these differences., Methods: Metabolite profiling was conducted in Iraqi immigrants (n = 93) and native Swedes (n = 77) using two complementary mass spectrometry-based platforms. Differences in metabolite levels were compared after adjustment for confounding anthropometric, diet and clinical variables., Results: The Iraqi immigrant population were more obese (44.1 vs 24.7%, p < 0.05), but had a lower prevalence of hypertension (32.3 vs 54.8%, p < 0.01) than the native Swedish population. We detected 140 metabolites, 26 of which showed different levels between populations (q < 0.05,) after adjustment for age, sex, BMI, T2D and use of metformin. Twenty-two metabolites remained significant after further adjustment for HOMA-IR, HOMA-beta or insulin sensitivity index. Levels of polyunsaturated acylcarnitines (14:2 and 18:2) and fatty acid (18:2) were higher, whereas those of saturated and monounsaturated acylcarnitines (14:0, 18:1, and 8:1), fatty acids (12:0, 14:0, 16:0, and 18:1), uremic solutes (urate and quinate) and ketone bodies (beta-hydroxybutyrate) were lower in Iraqi immigrants. Further, levels of phospholipids were generally lower in the Iraqi immigrant population., Conclusions: Our result suggests an overall beneficial lipid profile in Iraqi immigrants, despite a higher risk to develop T2D. Higher levels of polyunsaturated fatty acids may suggest differences in dietary pattern, which in turn may reduce the risk of hypertension.

Diabetes is a bihormonal disorder resulting from combined insulin and glucagon secretion defects. Mice lacking fumarase (Fh1) in their β cells (Fh1βKO mice) develop progressive hyperglycemia and dysregulated glucagon secretion similar to that seen in diabetic patients (too much at high glucose and too little at low glucose). The glucagon secretion defects are corrected by low concentrations of tolbutamide and prevented by the sodium-glucose transport (SGLT) inhibitor phlorizin. These data link hyperglycemia, intracellular Na + accumulation, and acidification to impaired mitochondrial metabolism, reduced ATP production, and dysregulated glucagon secretion. Protein succination, reflecting reduced activity of fumarase, is observed in α cells from hyperglycemic Fh1βKO and β-V59M gain-of-function K ATP channel mice, diabetic Goto-Kakizaki rats, and patients with type 2 diabetes. Succination is also observed in renal tubular cells and cardiomyocytes from hyperglycemic Fh1βKO mice, suggesting that the model can be extended to other SGLT-expressing cells and may explain part of the spectrum of diabetic complications., (Copyright © 2018 The Authors. Published by Elsevier Inc. All rights reserved.)

The influence of instrumental parameters affecting the ionization in continuous full filling capillary electrochromatography/electrospray ionization mass spectrometry (CFF-CEC/ESI-MS) was investigated. The investigated parameters were the BGE and sheath liquid ion strength and organic modifier content, the nebulizer gas pressure, and the concentration of nanoparticles in the BGE. It was found that the nebulizer pressure had the largest influence on the separation efficiency and apparent retention. It was shown that even the lowest pressure investigated was sufficient to guide the nanoparticle flow away from the mass spectrometer inlet. A nebulizer pressure of 5 psi was found to be optimal; increasing the pressure significantly decreased the separation efficiency due to the generation of a hydrodynamic flow. Generally, the ion strength of both the BGE and the sheath liquid were found to have very moderate effects on the separation of a homologous series of dialkyl phthalates, whereas the ionization efficiency was found to be unaffected by the nanoparticles and the separation efficiency was found to increase with increasing concentrations up to 3.8 mg/mL, whereafter it was observed to drop. The optimized method was linear over a wide concentration range and presented LOD and LOQ more than threefold lower than those previously reported using CFF-CEC/ESI-MS., (Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Tight coupling between cytosolic and mitochondrial metabolism is key for GSIS (glucose-stimulated insulin secretion). In the present study we examined the regulatory contribution of PDH (pyruvate dehydrogenase) kinase 1, a negative regulator of PDH, to metabolic coupling in 832/13 clonal beta-cells. Knockdown of PDH kinase 1 with siRNA (small interfering RNA) reduced its mRNA (>80%) and protein level (>40%) after 72 h. PDH activity, glucose-stimulated cellular oxygen consumption and pyruvate-stimulated mitochondrial oxygen consumption increased 1.7- (P<0.05), 1.6- (P<0.05) and 1.6-fold (P<0.05) respectively. Gas chromatography/MS revealed an altered metabolite profile upon silencing of PDH kinase 1, determined by increased levels of the tricarboxylic acid cycle intermediates malate, fumarate and alpha-ketoglutarate. These metabolic alterations were associated with exaggerated GSIS (5-fold compared with 3.1-fold in control cells; P<0.01). Insulin secretion, provoked by leucine and dimethylsuccinate, which feed into the tricarboxylic acid cycle bypassing PDH, was unaffected. The oxygen consumption and metabolic data strongly suggest that knockdown of PDH kinase 1 in beta-cells permits increased metabolic flux of glucose-derived carbons into the tricarboxylic acid cycle via PDH. Enhanced insulin secretion is probably caused by increased generation of tricarboxylic acid cycle-derived reducing equivalents for mitochondrial electron transport to generate ATP and/or stimulatory metabolic intermediates. On the basis of these findings, we suggest that PDH kinase 1 is an important regulator of PDH in clonal beta-cells and that PDH kinase 1 and PDH are important for efficient metabolic coupling. Maintaining low PDH kinase 1 expression/activity, keeping PDH in a dephosphorylated and active state, may be important for beta-cells to achieve the metabolic flux rates necessary for maximal GSIS.

Metabolites generated from fuel metabolism in pancreatic beta-cells control exocytosis of insulin, a process which fails in type 2 diabetes. To identify and quantify these metabolites, global and unbiased analysis of cellular metabolism is required. To this end, polar metabolites, extracted from the clonal 832/13 beta-cell line cultured at 2.8 and 16.7 mM glucose for 48 h, were derivatized followed by identification and quantification, using gas chromatography (GC) and mass spectrometry (MS). After culture at 16.7 mM glucose for 48 h, 832/13 beta-cells exhibited a phenotype reminiscent of glucotoxicity with decreased content and secretion of insulin. The metabolomic analysis revealed alterations in the levels of 7 metabolites derived from glycolysis, the TCA cycle and pentose phosphate shunt, and 4 amino acids. Principal component analysis of the metabolite data showed two clusters, corresponding to the cells cultured at 2.8 and 16.7 mM glucose, respectively. Concurrent changes in protein expression were analyzed by 2-D gel electrophoresis followed by LC-MS/MS. The identities of 86 spots corresponding to 75 unique proteins that were significantly different in 832/13 beta-cells cultured at 16.7 mM glucose were established. Only 5 of these were found to be metabolic enzymes that could be involved in the metabolomic alterations observed. Anticipated changes in metabolite levels in cells exposed to increased glucose were observed, while changes in enzyme levels were much less profound. This suggests that substrate availability, allosteric regulation, and/or post-translational modifications are more important determinants of metabolite levels than enzyme expression at the protein level.