1.5,6-δ-DHTL, a stable metabolite of arachidonic acid, is a potential substrate for paraoxonase 1.
Eryanni-Levin S1, Khatib S2, Levy-Rosenzvig R1, Tamir S1, Szuchman-Sapir A3. Biochim Biophys Acta. 2015 Sep;1851(9):1118-22. doi: 10.1016/j.bbalip.2015.04.008. Epub 2015 May 6.
Paraoxonase 1 (PON1) is an antiatherogenic high density lipoprotein-associated lactonase. Recent findings revealed that PON1 knockout mice have low blood pressure, which is negatively correlated with the level of 5,6-epoxyeicosatrienoic acid (5,6-EET), a cytochrome P450 -derived arachidonic acid metabolite. 5,6-EET is an endothelium-derived hyperpolarizing factor that causes arterial dilation. Under physiological conditions, 5,6-EET is unstable, transforming to its δ-lactone (5,6-δ-DHTL) that evades the degradation by soluble epoxide hydrolase (sEH), arguing for the existence of yet another enzyme that is responsible specifically for its hydrolysis. We therefore hypothesized that PON1 degrades the 5,6-δ-DHTL, and this specific PON1 lactonase activity thus decreases endothelial vasodilatation. The aim of the present study was to investigate the PON1-5,6-δ-DHTL relationship. A liquid chromatography mass spectrometry based method for 5,6-EET derivatives identification was developed.
2.Photopatterned Multidomain Gels: Multi-Component Self-Assembled Hydrogels Based on Partially Self-Sorting 1,3:2,4-Dibenzylidene-D-sorbitol Derivatives.
Cornwell DJ1, Daubney OJ1, Smith DK1. J Am Chem Soc. 2015 Dec 16;137(49):15486-92. doi: 10.1021/jacs.5b09691. Epub 2015 Dec 8.
We report a multicomponent self-assembling system based on 1,3:2,4-dibenzyldene-D-sorbitol (DBS) derivatives which form gels as the pH is lowered in a controlled way. The two DBS gelators are functionalized with carboxylic acids: the first in the 4-position of the aromatic rings (DBS-CO2H), the second having glycine connected through an amide bond and displaying a terminal carboxylic acid (DBS-Gly). Importantly, these two self-assembling DBS-acids have different pKa values, and as such, their self-assembly is triggered at different pHs. Slowly lowering the pH of a mixture of gelators using glucono-δ-lactone (GdL) initially triggers assembly of DBS-CO2H, followed by DBS-Gly; a good degree of kinetic self-sorting is achieved. Gel formation can also be triggered in the presence of diphenyliodonium nitrate (DPIN) as a photoacid under UV irradiation. Two-step acidification of a mixture of gelators using (a) GdL and (b) DPIN assembles the two networks sequentially.
3.Yogurt made from milk heated at different pH values.
Ozcan T1, Horne DS2, Lucey JA3. J Dairy Sci. 2015 Oct;98(10):6749-58. doi: 10.3168/jds.2015-9643. Epub 2015 Jul 29.
Milk for yogurt manufacture is subjected to high heat treatment to denature whey proteins. Low milk pH values (≤ 6.5) at heating result in most denatured whey proteins becoming associated with casein micelles, whereas high milk pH values (≥ 7.0) at heating result in the formation of mostly soluble (nonmicellar) denatured whey protein complexes. There are conflicting reports on the relative importance of soluble and casein-bound whey protein aggregates on the properties of acid gels. Prior studies investigating the effect of pH of milk at heating used model gels in which milk was acidified by glucono-δ-lactone; in this study, we prepared yogurt gels using commercial starter cultures. Model acid gels can have very different texture and physical properties from those made by fermentation with starter cultures. In this study, we investigated the effects of different pH values of milk at heating on the rheological, light backscatter, and microstructural properties of yogurt gels.
4.Systemic alterations in the metabolome of diabetic NOD mice delineate increased oxidative stress accompanied by reduced inflammation and hypertriglyceremia.
Fahrmann J1, Grapov D1, Yang J2, Hammock B2, Fiehn O1, Bell GI3, Hara M4. Am J Physiol Endocrinol Metab. 2015 Jun 1;308(11):E978-89. doi: 10.1152/ajpendo.00019.2015. Epub 2015 Apr 7.
Nonobese diabetic (NOD) mice are a commonly used model of type 1 diabetes (T1D). However, not all animals will develop overt diabetes despite undergoing similar autoimmune insult. In this study, a comprehensive metabolomic approach, consisting of gas chromatography time-of-flight (GC-TOF) mass spectrometry (MS), ultra-high-performance liquid chromatography-accurate mass quadruple time-of-flight (UHPLC-qTOF) MS and targeted UHPLC-tandem mass spectrometry-based methodologies, was used to capture metabolic alterations in the metabolome and lipidome of plasma from NOD mice progressing or not progressing to T1D. Using this multi-platform approach, we identified >1,000 circulating lipids and metabolites in male and female progressor and nonprogressor animals (n = 71). Statistical and multivariate analyses were used to identify age- and sex-independent metabolic markers, which best differentiated metabolic profiles of progressors and nonprogressors.