Current estimates of biogenic emissions from Eucalypts uncertain for Southeast Australia

The biogenic emissions of isoprene and monoterpenes are one of the main drivers of atmospheric photochemistry, including oxidant and secondary organic aerosol production. In this paper, the emission rates of isoprene and monoterpenes from Australian vegetation are investigated for the first time using the Model of Emissions of Gases and Aerosols from Nature version 2.1 (MEGANv2.1); the CSIRO chemical transport model; and atmospheric observations of isoprene, monoterpenes and isoprene oxidation products (methacrolein and methyl vinyl ketone). Observations from four field campaigns during three different seasons are used, covering urban, coastal suburban and inland forest areas. The observed concentrations of isoprene and monoterpenes were of a broadly similar magnitude, which may indicate that southeast Australia holds an unusual position where neither chemical species dominates. The model results overestimate the observed atmospheric concentrations of isoprene (up to a factor of 6) and underestimate the monoterpene concentrations (up to a factor of 4). This may occur because the emission rates currently used in MEGANv2.1 for Australia are drawn mainly from young eucalypt trees (\u3c 7 years), which may emit more isoprene than adult trees. There is no single increase/decrease factor for the emissions which suits all seasons and conditions studied. There is a need for further field measurements of in situ isoprene and monoterpene emission fluxes in Australia

A possible role for miRNA silencing in disease phenotype variation in Swedish transthyretin V30M carriers

Our results are the first to show the presence of a 3'UTR polymorphism on the V30M haplotype in Swedish carriers, which can serve as a miRNA binding site potentially leading to down-regulated expression from the mutated TTR allele. This finding may be related to the low penetrance and high age at onset of the disease observed in the Swedish patient population

Differential gene expression between wild-type and Gulo-deficient mice supplied with vitamin C

The aim of this study was to test the hypothesis that hepatic vitamin C (VC) levels in VC deficient mice rescued with high doses of VC supplements still do not reach the optimal levels present in wild-type mice. For this, we used a mouse scurvy model (sfx) in which the L-gulonolactone oxidase gene (Gulo) is deleted. Six age- (6 weeks old) and gender- (female) matched wild-type (WT) and sfx mice (rescued by administering 500 mg of VC/L) were used as the control (WT) and treatment (MT) groups (n = 3 for each group), respectively. Total hepatic RNA was used in triplicate microarray assays for each group. EDGE software was used to identify differentially expressed genes and transcriptomic analysis was used to assess the potential genetic regulation of Gulo gene expression. Hepatic VC concentrations in MT mice were significantly lower than in WT mice, even though there were no morphological differences between the two groups. In MT mice, 269 differentially expressed transcripts were detected (≥ twice the difference between MT and WT mice), including 107 up-regulated and 162 down-regulated genes. These differentially expressed genes included stress-related and exclusively/predominantly hepatocyte genes. Transcriptomic analysis identified a major locus on chromosome 18 that regulates Gulo expression. Since three relevant oxidative genes are located within the critical region of this locus we suspect that they are involved in the down-regulation of oxidative activity in sfx mice

Oxidative protein labeling in mass-spectrometry-based proteomics

Oxidation of proteins and peptides is a common phenomenon, and can be employed as a labeling technique for mass-spectrometry-based proteomics. Nonspecific oxidative labeling methods can modify almost any amino acid residue in a protein or only surface-exposed regions. Specific agents may label reactive functional groups in amino acids, primarily cysteine, methionine, tyrosine, and tryptophan. Nonspecific radical intermediates (reactive oxygen, nitrogen, or halogen species) can be produced by chemical, photochemical, electrochemical, or enzymatic methods. More targeted oxidation can be achieved by chemical reagents but also by direct electrochemical oxidation, which opens the way to instrumental labeling methods. Oxidative labeling of amino acids in the context of liquid chromatography(LC)–mass spectrometry (MS) based proteomics allows for differential LC separation, improved MS ionization, and label-specific fragmentation and detection. Oxidation of proteins can create new reactive groups which are useful for secondary, more conventional derivatization reactions with, e.g., fluorescent labels. This review summarizes reactions of oxidizing agents with peptides and proteins, the corresponding methodologies and instrumentation, and the major, innovative applications of oxidative protein labeling described in selected literature from the last decade

New Anthocyanins from Black Elderberry of Inhibitory Potential Revealed by Mass Spectrometry

Background: A resurgent interest in the use of natural product based inhibitors against the influenza virus has resulted from the widespread resistance to current antiviral therapeutics among circulating strains. Natural products derived from food sources in particular, offer the benefit of a safer pharmacological profile and may offer broader health benefits.Objective: To identify new anthocyanins from black elderberry (Sambucus nigra) that will inhibit the function of influenza neuraminidase while avoiding complications associated with mutations in the active site of strains resistant to current inhibitors.Method: The mild solvent extraction process minimizes the exposure of the anthocyanins to non-acidic pH solutions, high temperature and pressure, and ambient light, in order to prevent their chemical transformation or degradation. Total anthocyanin yields are equivalent or better to those reported based on the recovery of cyanidin-3-O-glucoside. The characterization of additional anthocyanin components has been achieved by liquid chromatography coupled to electrospray ionization mass spectrometry (LC-ESI-MS) in conjunction with tandem mass spectrometry (MS/MS).Results: The results demonstrate an improved mild recovery method that has enabled the isolation and detection of previously unidentified minor anthocyanin components in elderberry of inhibitory potential against the influenza virus including prenylated cyanidin-3-O-sambubioside, prenylated and other derivatives of cyanidin-3-acetylrutinoside, and a type A proanthocyanin dimer of cyanidin-3-O-sambubioside.Conclusion: The improved recovery of anthocyanins from elderberries, under mild extraction conditions in a manner that preserves their structural integrity, and which yields a wider variety of previously unidentified compounds, should aid in their use and development in the treatment of influenza infections

Coated glass capillaries as SPME devices for DART mass spectrometry.

RationaleSolid-phase microextraction (SPME) provides high-throughput sample cleanup and pre-concentration. Here we demonstrate coated glass capillaries (CGCs) as SPME devices for specific applications in direct analysis in real time (DART) mass spectrometry, referred to as "CGC-DART", for rapid screening of environmental contaminants at low parts-per-trillion detection limits and with accurate identification of analytes.MethodsThe extraction is performed in a one-step process in minutes by dipping the CGC in solutions containing the analytes, and then placing the CGC in a DART source for analysis. CGCs are disposable and relatively inexpensive in comparison with SPME devices, and can be prepared with hydrophobic, hydrophilic or mixed-mode materials similar to SPME. CGCs were prepared by adsorption coating with incubation of capillaries in saturated solutions of octadecylamine or covalent activation of silanes.ResultsQuantitation is shown with perfluorooctanoic acid (PFOA) at 1 ppt to 100 ppb, with the lowest detection at 500 parts-per quadrillion (ppq) in tap water. One-step extraction of contaminated groundwater from Northern Queensland, Australia, revealed perfluorooctane sulfonate (PFOS) and perfluorohexanesulfonamide as well as C4-C8 perfluoroalkyl carboxylic acids. A soil sample taken near a former military air base (New Hampshire, USA) revealed the presence of perfluorononanoic acid (PFNA) at 1 ppb and traces of perfluoroheptanoic acid.ConclusionsCGC-DART enabled one-step extraction of PFASs in minutes with mL sample volumes at low concentrations as shown for the standards and contaminated soil and water samples. DART-MS combined with Kendrick mass defect analysis enabled accurate identification of PFASs without chromatography steps, as fluorinated compounds are mass deficient and easily distinguished over background signal

Protein Footprinting with Radical Probe Mass Spectrometry- Two Decades of Achievement

Background: Radical Probe Mass Spectrometry (RP-MS) describes a pioneering methodology in structural biology that enables the study of protein structures, their interactions, and dynamics on fast timescales (down to sub-milliseconds). Hydroxyl radicals (•OH) generated directly from water within aqueous solutions induce the oxidation of reactive, solvent accessible amino acid side chains that are then analyzed by mass spectrometry. Introduced in 1998 at the American Society for Mass Spectrometry annual conference, RP-MS was first published on in 1999. Objective: This review article describes developments and applications of the RP-MS methodology over the past two decades. Methods: The RP-MS method has been variously referred to as synchrotron X-ray radiolysis footprinting, Hydroxyl Radical Protein Footprinting (HRPF), X-ray Footprinting with Mass Spectrometry (XF-MS), Fast Photochemical Oxidation of Proteins (FPOP), oxidative labelling, covalent oxidative labelling, and even the Stability of Proteins from Rates of Oxidation (SPROX). Results: The article describes the utility of hydroxyl radicals as a protein structural probe, the advantages of RP-MS in comparison to other MS-based approaches, its proof of concept using ion mobility mass spectrometry, its application to protein structure, folding, complex and aggregation studies, its extension to study the onset of protein damage, its implementation using a high throughput sample loading approach, and the development of protein docking algorithms to aid with data analysis and visualization. Conclusion: RP-MS represents a powerful new structural approach that can aid in our understanding of the structure and functions of proteins, and the impact of sustained oxidation on proteins in disease pathogenesis.</jats:sec