SUMMARY Metabolic decoys are synthetic analogs of naturally occurring biosynthetic acceptors. These compounds divert cellular biosynthetic pathways by acting as artificial substrates that usurp the activity of natural enzymes. While O-linked glycosides are common, they are only partially effective even at millimolar concentrations. In contrast, we report that N-acetylglucosamine (GlcNAc) incorporated into various thioglycosides robustly truncate cell-surface N- and O-linked glycan biosynthesis at 10–100μM concentrations. The >10 fold greater inhibition is in part due to the resistance of thioglycosides to hydrolysis by intracellular hexosaminidases. The thioglycosides reduce β-galactose incorporation into lactosamine chains, cell-surface sialyl Lewis-X expression, and leukocyte rolling on selectin-substrates including inflamed endothelial cells under fluid shear. Treatment of granulocytes with thioglycosides prior to murine infusion inhibited neutrophil homing to sites of acute inflammation and bone marrow by ~80–90%. Overall, thioglycosides represent an easy to synthesize class of efficient metabolic inhibitors/decoys. They reduce N-/O-linked glycan biosynthesis and inflammatory leukocyte accumulation.

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Collagen molecules, self-assembled into macroscopic hierarchical tissue networks, are the main organic building block of many biological tissues. A particularly common and important form of this self-assembly consists of type I collagen fibrils, which exhibit a nanoscopic signature, D-periodic gap/overlap spacing, with a distribution of values centered at approximately 67 nm. In order to better understand the relationship between type I collagen self-assembly and D-spacing distribution, we investigated surface-mediated collagen self-assembly as a function of substrate and incubation concentration. Collagen fibril assembly on phlogopite and muscovite mica as well as fibrillar gel coextrusion in glass capillary tubes all exhibited D-spacing distributions similar to those commonly observed in biological tissues. The observation of D-spacing distribution by self-assembly of type I collagen alone is significant as it eliminates the necessity to invoke other preassembly or postassembly hypotheses, such as variation in the content of collagen types, enzymatic cross-linking, or other post-translational modifications, as mechanistic origins of D-spacing distribution. The D-spacing distribution on phlogopite mica is independent of type I collagen concentration, but on muscovite mica D-spacing distributions showed increased negative skewness at 20 μg/mL and higher concentrations. Tilted D-spacing angles were found to correlate with decreased D-spacing measurements, an effect that can be removed with a tilt angle correction, resulting in no concentration dependence of D-spacing distribution on muscovite mica. We then demonstrated that tilted D-spacing is uncommon in biological tissues and it does not explain previous observations of low D-spacing values in ovariectomized dermis and bone.

BackgroundMicroalgae are uniquely advantageous organisms cultured and harvested for several value-added biochemicals. A majority of these compounds are lipid-based, such as triacylglycerols (TAGs), which can be used for biofuel production, and their accumulation is most affected under nutrient stress conditions. As such, the balance between cellular homeostasis and lipid metabolism becomes more intricate to achieve efficiency in bioproduct synthesis. Lipidomics studies in microalgae are of great importance as biochemical diversity also plays a major role in lipid regulation among oleaginous species.MethodsThe aim of this study was to analyze time-series changes in lipid families produced by microalga under different nutrient conditions and growth phases to gain comprehensive information at the cellular level. For this purpose, we worked with a highly adaptable, oleaginous, non-model green microalga species, Ettlia oleoabundans (a.k.a. Neochloris oleoabundans). Using a mass spectrometry-based untargeted and targeted metabolomics’ approach, we analyzed the changes in major lipid families under both replete and deplete nitrogen and phosphorus conditions at four different time points covering exponential and stationary growth phases.ResultsComprehensive analysis of the lipid metabolism highlighted the accumulation of TAGs, which can be utilized for the production of biodiesel via transesterification, and depletion of chlorophylls and certain structural lipids required for photosynthesis, under nutrient deprived conditions. We also found a correlation between the depletion of digalactosyldiacylglycerols (DGDGs) and sulfoquinovosyldiacylglycerols (SQDGs) under nutrient deprivation.ConclusionsHigh accumulation of TAGs under nutrient limitation as well as a depletion of other lipids of interest such as phosphatidylglycerols (PGs), DGDGs, SQDGs, and chlorophylls seem to be interconnected and related to the microalgal photosynthetic efficiency. Overall, our results provided key biochemical information on the lipid regulation and physiology of a non-model green microalga, along with optimization potential for biodiesel and other value-added product synthesis.Electronic supplementary materialThe online version of this article (10.1186/s13068-018-1026-y) contains supplementary material, which is available to authorized users.

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14Microalgae are promising feedstocks for biofuels and other value-added biochemicals. Ettlia 15 oleoabundans, a non-model green microalgae, produces increased levels of key precursors for 16 lipid-based biofuels under nutrient stress conditions. Here, we introduce a method for analysis of 17 hydrophobic metabolites in E. oleoabundans and apply this method to microalgae grown under 18 different nutrient conditions. We combined targeted analysis using gas chromatography/ tandem 19 mass spectrometry (GC-MS/MS) with targeted and untargeted metabolomics using liquid 20 chromatography-quadrupole-time-of-flight mass spectrometry (LC-Q-ToF MS). Our method 21 allows simultaneous detection of compounds from major lipid families, and other value-added 22 biochemicals using less biomass, hence allowing analysis of larger number of samples to be 23 processed simultaneously. In this study, we showed that 202 metabolites were enhanced or 24 depleted under nutrient stress and annotated 163 of these species. A complex regulation of 25 different classes of metabolites under nutrient stress was observed. Overall, triacylglycerols and 26 sulfoquinovosyldiacylglycerols were accumulated, chlorophylls were depleted, and 27 diacylglycerols were differentially regulated at the molecular level when grown under limited 28 nutrient conditions. The method that we developed will serve as a template for targeted and 29 untargeted metabolomics in E. oleoabundans and other non-model microalgae to understand 30 biochemical regulations under different experimental conditions. 31

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Introduction: Hypertension and diabetes are issues in the US especially in the south. In Arkansas, an estimated 797,000 adults have prediabetes and are at risk for diabetes. We aimed to assess cardiometabolic risk factors and impact of nutrition-related indicators in self-identified diabetes and hypertension patients and those at risk. Method: Data were analyzed from the 2008 Arkansas Cardiovascular Health Examination Survey (n=1,383), which used probability sampling to obtain a representative sample of Arkansas residents. A self-report survey was administered on health history, socioeconomic status (SES), lifestyle, and diet. Blood biomarkers were measured and compared for those who self-reported diabetes or hypertension with those who were at risk. Results: We used t-tests for continuous variables and chi-square test for categorical variables with statistical significance at p<0.05. We hypothesized that participants with undiagnosed diabetes or hypertension had less access to care (SES as a surrogate) and worse health behavior than the diagnosed groups. Significant differences in SES, behaviors, nutrients, and biomarkers were observed between healthy vs. both diagnosed and undiagnosed groups. Surprisingly, we found that undiagnosed groups had higher average food security than the diagnosed groups. Also, some of the health behaviors including alcohol consumption were 5-6 fold higher among the undiagnosed and healthy groups as compared to currently diagnosed diabetes group. Moderate physical activity was about 2 fold higher among the healthy (5.5 hours/week) as compared to undiagnosed hypertension group (3 hours/week). In addition, the currently diagnosed groups seem to have some improved dietary habits based on higher levels of vegetable and fruit consumption and lower blood cholesterol. We have also found that both the healthy and undiagnosed diabetes groups had above normal or high triglyceride levels. Conclusion: Undiagnosed diabetes and hypertension do not have serious symptoms, but are dangerous health conditions. From our findings, targeted education should be implemented among all people, especially on access to food, vegetable and fruit consumption, alcohol use, physical activity, cholesterol and triglyceride levels.