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Examines the proteomics using high-efficiency multiple-capillary liquid chromatography (MCLC) with electrospray ionization mass spectrometry (MS). Description of a dual-capillary column device in a multi-capillary LC system.

Studies have shown the electron shuttling role of humic substances (HS) in enhancing microbial reduction of solid-phase Fe(III), but it is unknown if native HS can reduce structural Fe(III) in clays and how their chemical properties affect this process and secondary mineralization. The objective of this study was to evaluate the role of natural HS, Leonarditehumic acid (LHA), and Pahokee Peat humic acid (PPHA) in reducing structural Fe(III) in nontronite with or without Shewanellaputrefaciens. The extent of Fe(III) reduction was determined with a wet chemical method. Electrochemical methods, spectroscopy, and mass spectrometry were used to determine the changes of HS electrochemical and molecular composition after bioreduction. X-ray diffraction and electron microscopy were used to observe mineralogical transformations. The results showed that natural HS not only served as an electron donor to abiotically reduce Fe(III) in nontronite but also served as an electron shuttle to enhance Fe(III) bioreduction by S. putrefaciens. In the presence of CN32 cells, both the rate and extent of Fe(III) reduction significantly increased. Between the two HS, PPHA was more effective. The final bioreduction extents were 12.2 and 17.8% with LHA and PPHA, respectively, in bicarbonate buffer. Interestingly, when CN32 cells were present, LHA and PPHA donated more electrons to NAu-2, suggesting that CN32 cells were able to make additional electrons of LHA and PPHA available to reduce structural Fe(III). Although LHA reduced less Fe(III), it induced more extensive mineral transformation. In contrast, PPHA reduced more Fe(III) but did not induce any mineralogical change. These contrasting behaviors between the two humic acids are ascribed to their differences in electron-donating capacity, reactive functional group distribution, and metal complexation capacity. A unique set of secondary minerals, including talc, illite, silica, albite, ilmenite, and ferrihydrite formed as a result of reduction. The results highlight the importance of coupled C and Fe biogeochemical transformations and have implications for nutrient cycling and contaminant migration in the environment. [ABSTRACT FROM AUTHOR]

Molecular composition of dissolved organic matter (DOM) and its influencing factors in river reservoirs remains elusive. Here, molecular compositions of DOM, bacterial community structures, and water physiochemistry were investigated in the field and microcosm samples of the Three Gorges Reservoir (TGR). The results showed that DOM molecular compositions were significantly (R2 = 0.245, p < 0.001) correlated with bacterial community structures in the studied field samples, suggesting that bacteria may actively interact with DOM molecules. The molecular compositions of DOM in the studied field samples were significantly (p < 0.05) affected by the distance between the sample sites and the Three Gorges Dam and by bacterial groups of Actinobacteria and Alphaproteobacteria , suggesting that both hydrological and bacterial processes may contribute to the variation in DOM molecular composition in the TGR water. Furthermore, microcosm experiments demonstrated that both microbial and abiotic processes may transform and/or produce DOM in the TGR, thereby affecting DOM molecular composition. Microbial process increased the average aromaticity index and decreased the carbon number of DOM molecules with increasing incubation duration; whereas average oxygen number, double bond equivalent, and oxidation state of carbon of DOM molecules increased during the first 14 days of incubation and began to decrease thereafter. Taken together, this study expands our understanding of the impact of microbial process on the DOM molecular composition in reservoir ecosystems, and has great implications for carbon cycling in major rivers. [ABSTRACT FROM AUTHOR]

Secondary organic aerosol (SOA), formed in the photooxidation of diesel fuel, biodiesel fuel, and 20% biodiesel fuel/80% diesel fuel mixture, are prepared under high-NOx conditions in the presence and absence of sulfur dioxide (SO2), ammonia (NH3), and relative humidity (RH). The composition of condensed-phase organic compounds in SOA is measured using several complementary techniques including aerosol mass spectrometry (AMS), high-resolution nanospray desorption electrospray ionization mass spectrometry (nano-DESI/HRMS), and ultrahigh resolution and mass accuracy 21T Fourier transform ion cyclotron resonance mass spectrometry (21T FT-ICR MS). Results demonstrate that sulfuric acid and condensed organosulfur species formed in photooxidation experiments with SO2 are present in the SOA particles. Fewer organosulfur species are formed in the high humidity experiments, performed at RH 90%, in comparison with experiments done under dry conditions. There is a strong overlap of organosulfur species observed in this study with previous field and chamber studies of SOA. Many MS peaks of organosulfates (R-OS(O)2OH) previously designated as biogenic or of unknown origin in field studies might have originated from anthropogenic sources, such as photooxidation of hydrocarbons present in diesel and biodiesel fuel. [ABSTRACT FROM AUTHOR]

The relatively poor solubility of lignin in most pretreatment solvents remains one of the biggest challenges in lignin valorization to improve overall biorefinery economics. In this work, rapid room temperature solubilization of lignin at high solid loadings (＞30 wt%) can be easily achieved in a single step using ethylene glycol (EG). The solubilized lignin can be rapidly and quantitatively recovered with the addition of ethanol. The computational and nuclear magnetic resonance (NMR) spectroscopic studies confirm that strong hydrogen bond interactions between EG and the free hydroxyl groups present in lignin contribute to the lignin dissolution. In addition, hydrogen peroxide mediated depolymerization of the dissolved lignin at a low temperature (80 °C) was tested and the effect of EG molecules on depolymerization of lignin was also theoretically studied. The findings of this work provide mechanistic insights of hydrogen bond interactions in high lignin solubilization and valorization. [ABSTRACT FROM AUTHOR]

Microbial degradation of soil organic matter (SOM) is a key process for terrestrial carbon cycling, although the molecular details of these transformations remain unclear. This study reports the application of ultrahigh resolution mass spectrometry to profile the molecular composition of SOM and its degradation during a simulated warming experiment. A soil sample, collected near Barrow, Alaska, USA, was subjected to a 40-day incubation under anoxic conditions and analyzed before and after the incubation to determine changes of SOM composition. A CHO index based on molecular C, H, and O data was utilized to codify SOM components according to their observed degradation potentials. Compounds with a CHO index score between –1 and 0 in a water-soluble fraction (WSF) demonstrated high degradation potential, with a highest shift of CHO index occurred in the N-containing group of compounds, while similar stoichiometries in a base-soluble fraction (BSF) did not. Additionally, compared with the classical H:C vs O:C van Krevelen diagram, CHO index allowed for direct visualization of the distribution of heteroatoms such as N in the identified SOM compounds. We demonstrate that CHO index is useful not only in characterizing arctic SOM at the molecular level but also enabling quantitative description of SOM degradation, thereby facilitating incorporation of the high resolution MS datasets to future mechanistic models of SOM degradation and prediction of greenhouse gas emissions. [ABSTRACT FROM AUTHOR]

Accurate assignment of monoisotopic precursor masses to tandem mass spectrometric (MS/MS) data is a fundamental and critically important step for successful peptide identifications in mass spectrometry based proteomics. Here we describe an integrated approach that combines three previously reported methods of treating MS/MS data for precursor mass refinement. This combined method, "integrated post-experiment monoisotopic mass refinement" (iPE-MMR), integrates steps (1) generation of refined MS/MS data by DeconMSn; (2) additional refinement of the resultant MS/MS data by a modified version of PE-MMR; and (3) elimination of systematic errors of precursor masses using DtaRefinery. iPE-MMR is the first method that utilizes all MS information from multiple MS scans of a precursor ion including multiple charge states, in an MS scan, to determine precursor mass. With the combination of these methods, iPE-MMR increases sensitivity in peptide identification and provides increased accuracy when applied to complex high-throughput proteomics data. [ABSTRACT FROM AUTHOR]

Presents a high-throughput method for the characterization of a microorganism's dynamic proteome. Global enzymatic digestion; High-resolution liquid chromatographic separations; Fourier transform ion cyclotron resonance mass spectrometry.

Characterizes cellular proteome proteins for the understanding biochemical processes from cell differentiation to cancer development. Application of mass spectrometry for the investigation; Injection of protein extracts into capillary column for the separation; Introduction of peptides to an electrospray ionization.

Investigates the peptide hormone identification from protein digest using mass spectrometry coupled with capillary liquid chromatography. Application of capillary liquid chromatography for bovine serum albumin separation.

A suite of biomarkers, including amino acids, pigments, and lignin phenols coupled with high resolution mass spectrometry were used to evaluate differences in the sources and fate of organic matter (OM) in Everglades treatment wetlands as a model for OM cycling in shallow water wetlands. Five components of the system (water column particulate matter, vertical traps, flocculent material, periphyton, and surface soil) were assessed for OM transformations down-profile (i.e. water column to soil) and between treatment cells dominated by emergent aquatic vegetation (EAV) and submerged aquatic vegetation (SAV), with comparisons to reference sites within the remnant Everglades. We found that OM cycling is fundamentally different between EAV and SAV wetlands, and that SAV wetlands have some shared characteristics with similar habitats in the remnant Everglades. Other than locations densely populated by Typha spp., water column particulate organic C was predominantly derived from microbial/cryptomonad sources, rather than macroscopic sources (vascular plants and algal mats). Bacterial amino acid biomarkers were positively correlated with amino acid degradation indices and organic P (P o), respectively suggesting that microbial abundance is associated with less degraded OM, and that further investigation into relationships between microbial biomass and P o is warranted. Overall, this multi-biomarker approach can elucidate the relative degradation of OM pools, identify sources of OM, and highlight the importance of water column processes in shallow water wetlands. Image 1 • Biomarker degradation indices tracked organic matter (OM) decay. • Biomarkers indicated differences in OM sources between treatment wetland types. • Organic matter "freshness" and microbial biomarkers were positively correlated. • Amino acids were useful for characterizing OM composition and turnover. • Pigments were useful for identifying water column photosynthetic communities. [ABSTRACT FROM AUTHOR]

Removal of chemical oxygen demand (COD) from wastewater has been of considerable interest for several decades, but detailed mechanisms are poorly known. Here we present an environmental friendly method for removing COD from coking wastewater by using chemically reduced nontronite (rNAu-2). Hydroxyl radicals (·OH) produced from oxidation of structural Fe(II) in rNAu-2 in phosphate buffer at pH 6.5, oxidized various compounds in wastewater and thus significantly decreased COD (from 199.10 ± 0.90 to 80.4 ± 1.97 mg/L) within 120 h. The amount of COD removal was positively correlated with the amount of ·OH production, with removal efficiency depending on pH and buffer type. Mass spectrometric analysis of dissolved organic matter (DOM) suggested an oxidative pathway for COD removal. Excitation-emission matrix (EEM) fluorescence spectroscopy showed that aromatic protein-like compounds accounted for a large fraction of DOM in initial wastewater, but after rNAu-2 treatment, their proportion decreased. A sequential treatment of wastewater by rNAu-2 and a common wastewater bacterium Alcaligenes faecalis demonstrated that different orders of chemical and biological treatments affected COD removal efficiency, likely because chemical and microbial treatments targeted different compounds in coking wastewater. Unlabelled Image • ·OH produced by oxidation of reduced nontronite removed COD from coking wastewater. • Oxidation is a mechanism for COD removal by reduced nontronite. • A combined chemical and biological method enhanced COD removal. [ABSTRACT FROM AUTHOR]