Optimizing the Vanillin-Acid Sulfuric Method to Total Saponin Content in Leaves of Yerba Mate Clones.

Yerba mate (Ilex paraguariensis) is a forest species consumed in the form of non-alcoholic beverages in South America, with applications in foods, cosmetics, and pharmaceutical industries. The species leaves are globally recognized for their important bioactive compounds, including, saponins. We adjusted the vanillin-acid sulfuric method for determining spectrophotometrically the total saponin in yerba mate leaves. Seeking to maximize the extraction of saponins from leaves, a Doehlert design combined with Response Surface Methodology (RSM) was used, considering ethanol:water ratios and ultrasound times. In addition, the same methodology was used for the analysis of times and temperatures in the vanillin-sulfuric acid reaction heating. The contents of total saponin in mature leaves were compared in four yerba mate clones. The extraction was maximized using 40 % ethanol:60 % water and 60 minutes of ultrasound assisted extraction (UAE) without heating. For the reaction conditions, 70 °C for 10 minutes heating is recommended, and UV/Vis reading from 460 to 680 nm. Using the optimized methodology, total saponin contents ranged from 28.43 to 53.09 mg g-1 in the four yerba mate clones. The significant difference in saponin contents between clones indicate great genetic diversity and potential for clones' selection and extraction of these compounds from yerba mate leaves.

Reduced marine phytoplankton sulphur emissions in the Southern Ocean during the past seven glacials.

Marine biogenic sulphur affects Earth's radiation budget and may be an indicator of primary productivity in the Southern Ocean, which is closely related to atmospheric CO2 variability through the biological pump. Previous ice-core studies in Antarctica show little climate dependence of marine biogenic sulphur emissions and hence primary productivity, contradictory to marine sediment records. Here we present new 720,000-year ice core records from Dome Fuji in East Antarctica and show that a large portion of non-sea-salt sulphate, which was traditionally used as a proxy for marine biogenic sulphate, likely originates from terrestrial dust during glacials. By correcting for this, we make a revised calculation of biogenic sulphate and find that its flux is reduced in glacial periods. Our results suggest reduced dimethylsulphide emissions in the Antarctic Zone of the Southern Ocean during glacials and provide new evidence for the coupling between climate and the Southern Ocean sulphur cycle.

Chitosan-based nanocomposite matrices: Development and characterization.

Chitosan-based nanocomposites have a significant industrial impact related to the possibility to design and create new materials and structures. Cellulose nanocrystals (CNC) can be extracted from microcrystalline cellulose (MCC) by controlled acid hydrolysis with H2SO4. This work was focused on: to study the microstructure of CNC isolated from MCC after different hydrolysis times; to develop nanocomposites chitosan-based films; to characterize their structural and thermo-mechanical properties; to analyze the spectral differences among samples by means of ATR-FTIR in combination with principal component analysis (PCA) and square partial minimums model (PLS). It is worth noting that the selected condition for isolate the CNC from MCC was the acid treatment for 2 h, evidenced by size measurements. This fact was supported by transmission electron microscope (TEM) and dynamic light scattering (DLS). In this regard, SEM studies of films showed an assembly process between the nanocelluloses and the CH matrix. The incorporation of CNC into the films resulted in strong interactions between the filler and the matrix demonstrating the affinity between the phases and modifying the mechanical profiles. In summary, CNC was found to be a satisfactory reinforcing agent in biodegradable nanocomposite chitosan-based packaging and are promising as a means to develop tailor-made materials.

An approach for degradation of grape seed and skin proanthocyanidin polymers into oligomers by sulphurous acid.

To develop an efficient method for degradation of grape seed and skin proanthocyanidins polymers into oligomers, an optimized sulphurous acid degradation conditions for grape seed with the temperature of 60 °C, reaction time of 60 min and sample-sulphurous acid ratio of 1:0.2, and for grape skin with the temperature of 40 °C, reaction time of 60 min and sample-sulphurous acid ratio of 1:0.2, were established. Afterwards, HSCCC and prep-HPLC were used to fractionate and isolate individual proanthocyanidin oligomers from the degradation products. Total of ten dimeric or trimeric procyanidins were obtained, and most of them presented high yield (from 0.7 mg to 13.6 mg per run in grape seed and from 0.5 mg to 4.1 mg per run in grape skin) and high purity (over 90%). The proposed method provides a new way for large preparation of oligomeric proanthocyanidins from naturally abundant and wasted polymeric ones.

PRESS: PRotEin S-Sulfenylation server.

MOTIVATION: Transient S-sulfenylation of cysteine thiols mediated by reactive oxygen species plays a critical role in pathology, physiology and cell signaling. Therefore, discovery of new S-sulfenylated sites in proteins is of great importance towards understanding how protein function is regulated upon redox conditions. RESULTS: We developed PRESS (PRotEin S-Sulfenylation) web server, a server which can effectively predict the cysteine thiols of a protein that could undergo S-sulfenylation under redox conditions. We envisage that this server will boost and facilitate the discovery of new and currently unknown functions of proteins triggered upon redox conditions, signal regulation and transduction, thus uncovering the role of S-sulfenylation in human health and disease. AVAILABILITY AND IMPLEMENTATION: The PRESS web server is freely available at http://press-sulfenylation.cse.uoi.gr/ CONTACTS: agtzakos@gmail.com or gtzortzi@cs.uoi.gr SUPPLEMENTARY INFORMATION: Supplementary data are available at Bioinformatics online.

Pretreatment of Sugar Beet Pulp with Dilute Sulfurous Acid is Effective for Multipurpose Usage of Carbohydrates.

Sulfurous acid was used for pretreatment of sugar beet pulp (SBP) in order to achieve high efficiency of both extraction of carbohydrates and subsequent enzymatic hydrolysis of the remaining solids. The main advantage of sulfurous acid usage as pretreatment agent is the possibility of its regeneration. Application of sulfurous acid as hydrolyzing agent in relatively low concentrations (0.6-1.0 %) during a short period of time (10-20 min) and low solid to liquid ratio (1:3, 1:6) allowed effective extraction of carbohydrates from SBP and provided positive effect on subsequent enzymatic hydrolysis. The highest obtained concentration of reducing substances (RS) in hydrolysates was 8.5 %; up to 33.6 % of all carbohydrates present in SBP could be extracted. The major obtained monosaccharides were arabinose and glucose (9.4 and 7.3 g/l, respectively). Pretreatment of SBP with sulfurous acid increased 4.6 times the yield of glucose during subsequent enzymatic hydrolysis of remaining solids with cellulase cocktail, as compared to the untreated SBP. Total yield of glucose during SBP pretreatment and subsequent enzymatic hydrolysis amounted to 89.4 % of the theoretical yield. The approach can be applied directly to the wet SBP. Hydrolysis of sugar beet pulp with sulfurous acid is recommended for obtaining of individual monosaccharides, as well as nutritional media.

MDD-SOH: exploiting maximal dependence decomposition to identify S-sulfenylation sites with substrate motifs.

UNLABELLED: S-sulfenylation (S-sulphenylation, or sulfenic acid), the covalent attachment of S-hydroxyl (-SOH) to cysteine thiol, plays a significant role in redox regulation of protein functions. Although sulfenic acid is transient and labile, most of its physiological activities occur under control of S-hydroxylation. Therefore, discriminating the substrate site of S-sulfenylated proteins is an essential task in computational biology for the furtherance of protein structures and functions. Research into S-sulfenylated protein is currently very limited, and no dedicated tools are available for the computational identification of SOH sites. Given a total of 1096 experimentally verified S-sulfenylated proteins from humans, this study carries out a bioinformatics investigation on SOH sites based on amino acid composition and solvent-accessible surface area. A TwoSampleLogo indicates that the positively and negatively charged amino acids flanking the SOH sites may impact the formulation of S-sulfenylation in closed three-dimensional environments. In addition, the substrate motifs of SOH sites are studied using the maximal dependence decomposition (MDD). Based on the concept of binary classification between SOH and non-SOH sites, Support vector machine (SVM) is applied to learn the predictive model from MDD-identified substrate motifs. According to the evaluation results of 5-fold cross-validation, the integrated SVM model learned from substrate motifs yields an average accuracy of 0.87, significantly improving the prediction of SOH sites. Furthermore, the integrated SVM model also effectively improves the predictive performance in an independent testing set. Finally, the integrated SVM model is applied to implement an effective web resource, named MDD-SOH, to identify SOH sites with their corresponding substrate motifs. AVAILABILITY AND IMPLEMENTATION: The MDD-SOH is now freely available to all interested users at http://csb.cse.yzu.edu.tw/MDDSOH/. All of the data set used in this work is also available for download in the website. SUPPLEMENTARY INFORMATION: Supplementary data are available at Bioinformatics online. CONTACT: francis@saturn.yzu.edu.tw.

The control of emerging haloacetamide DBP precursors with UV/persulfate treatment.

Haloacetamides (HAcAms), an emerging class of nitrogen-containing disinfection byproducts (N-DBPs) of health concern in drinking water, have been reported to occur in treated drinking waters at low µg/L levels typically. The objective of this study was to examine the potential of an ultraviolet light/persulfate (UV/PS) oxidation technology to reduce the precursors of HAcAms and also minimize the formation of other N-DBPs upon subsequent chlorination. Low-pressure UV photolysis alone and PS pre-oxidation alone did not significantly affect HAcAm formation, however UV/PS pre-oxidation achieved a statistically significant reduction in HAcAm formation and also reduced bromine incorporation into the HAcAms. UV/PS also showed a good performance in removing the precursors of haloacetonitriles and halonitromethanes prior to chlorination. Therefore, UV/PS has the potential to minimize the formation of a range of N-DBPs in organic nitrogen-rich waters where N-DBP precursors are prevalent. However, these benefits should be weighed against the potential drawbacks of increased bromate and sulfate formation, particularly in high-bromide waters.

Cytotoxicity of sulfurous acid on cell membrane and bioactivity of Nitrosomonas europaea.

Nitrosomonas europaea, an ammonia oxidizing bacterium, was chosen as a research model to study the alteration of cell membrane in the presence of sulfurous acid and biodegradation of acetochlor. Significant changes of the outer cell membrane were observed in the presence of sulfurous acid using scanning electron microscopy (SEM) and Atomic Force Microscopy (AFM). The fluorescence polarization has shown a significant decrease in membrane fluidity and the increase of permeability of cell membrane. Lysozyme experiment show the cell becomes easily influenced by substance in medium. Inductively Coupled Plasma-Mass Spectrometry (ICP-MS) measurements show considerable amount of Ca(2+) and Mg(2+) in the supernatant from the sulfurous acid exposed cells. Sulfurous acid treatment enhanced the ability of N. europaea to degrade acetochlor. On this basis, it can be concluded that the increased cell permeability is favor for the absorbability of nutrition. As a result, N. europaea grows faster and the biodegradation efficiency was improved.

First and second deprotonation of H2SO4 on wet hydroxylated (0001) α-quartz.

We present an ab initio molecular dynamics study of deprotonation of sulfuric acid on wet quartz, a topic of atmospheric interest. The process is preferred, with 65% of our trajectories at 250 K showing deprotonation. The time distribution of the deprotonation events shows an exponential behavior and predicts an average deprotonation time of a few picoseconds. The process is exoergic, with most of the temperature increase being due to formation of hydrogen bonds prior to deprotonation. In agreement with existing studies of H2SO4 in water clusters, in liquid water, and at the air-water interface, the main determinant of deprotonation is the degree of solvation of H2SO4 by neighboring water molecules. However, we find that if both hydrogens of H2SO4 are simultaneously donated to water oxygens, deprotonation is disfavored. Predicted spectroscopic signatures showing the presence of solvated hydronium and bisulfate are presented. Increasing the temperature up to 330 K accelerates the process but does not change the main features of the deprotonation mechanisms or the spectroscopic signatures. The second deprotonation of H2SO4, studied only at 250 K, occurs provided there is sufficient solvation of the bisulfate by additional water molecules. In comparison to HCl deprotonation on the identical surface examined in our previous work, the first deprotonation of H2SO4 occurs more readily and releases more energy.

Detection of HSO4⁻ ion based on the hydrolysis of diketopyrrolopyrrole-derived Schiff base with chromogenic and fluorogenic dual signals.

A new diketopyrrolopyrrole-based Schiff base L was synthesized and its anion sensing behavior was explored. L showed exclusive response toward HSO4(-) ion and also distinguished HSO4(-) from other anions by color changes (from dark red to orange) and 21 fold fluorescence enhancement at 370 nm in aqueous solution (THF/H2O = 8/1, v/v). The sensing mechanism was suggested to proceed via a hydrolysis process. The results provided colorimetric and fluorimetric assays to selectively detect the presence of a HSO4(-) over a wide range of other interfering anions. The results could potentially be used as a dual colorimetric-fluorescent probe for monitoring HSO4(-) levels in physiological and environmental systems.

An amide based dipodal Zn(2+) complex: nano-molar detection of HSO(4) (−) in a semi-aqueous system.

A new chromogenic dipodal Zn2+ complex (4) bearing an amide group has been synthesized. The anion binding profile of this sensor was investigated with fluorescence and UV-Vis spectroscopy. The receptor 4 has high affinity for HSO4 − with a binding constant of 3.5 × 104 M−1 and a detection limit of 50 nM. The binding ability was confirmed with spectroscopic methods and density functional theory calculation (DFT).

[Chemical characteristics of water-soluble components of aerosol particles at different altitudes of the Mount Huang in the summer].

Aerosol was collected with Anderson cascade sampler at three altitudes of the Mount Huang in the summer 2011. Samples were analyzed by the ion chromatography (IC, Metrohm). The results showed that the mean mass concentrations of all the ions were 13.21 microg x m(-1), 10.94 microg x m(-3), 9.97 microg x m(-3), at the foot, mid height and the summit of the mountain, respectively. The mass concentration of water-soluble components of aerosol decreased with altitude. The major anion and cation of aerosols were SO4(2-) and NH4+, respectively. The descending order of mass concentration of major ionic species was: SO4(2-) > NH4+ > Ca2+ > NO3- and NH4+ account for about 75% of total ionic concentrations of PM2.1 in three sampling sites. The concentration of SO4(2-) and NH4+ decreased conspicuously with altitude. The major cation and anion of coarse mode particles were Ca2+ and NO3-, respectively. The slope of the linear regression line between anion and cation of PM10 and PM2.1 approximates 1, indicating acid-base balance in aerosol particles. Aerosols over the region Mount Huang were influenced by anthropogenic source of surrounding areas to a certain extent. The result also suggested that the correlation between NH4+ and SO4(2-) was 0. 98 and these ions predominantly existed in the form of (NH4)2SO4 and NH4HSO4. Backward trajectory analysis revealed that the air mass was originated from southern coastal regions, the East China Sea, the Yellow Sea and the northern China. Due to the northern air masses go through heavily polluted areas, concentrations of water-soluble ions in these air masses were higher than that of other air masses. The concentration of K+ in northern air mass was several times higher than that in southwestern air mass.

Microwave detection of sulfoxylic acid (HOSOH).

Sulfoxylic acid (HOSOH), a chemical intermediate roughly midway along the path between highly reduced (H2S) and highly oxidized sulfur (H2SO4), has been detected using Fourier transform microwave spectroscopy and double resonance techniques, guided by new high-level CCSD(T) quantum-chemical calculations of its molecular structure. Rotational spectra of the two most stable isomers of HOSOH, the putative ground state with C2 symmetry and the low-lying C(s) rotamer, have been measured to high precision up to 71 GHz, allowing accurate spectroscopic parameters to be derived for both isomers. HOSOH may play a role in atmospheric and interstellar chemistry, and the present work provides the essential data to enable remote sensing and/or radioastronomical searches for these species. Spectroscopic characterization of HOSOH suggests that other transient intermediates in the oxidation of SO2 to H2SO4 may be amenable to laboratory detection as well.

[Distribution of dimethylsulfoxide (DMSO) in the surface water of the Yellow Sea and the Bohai Sea].

The horizontal distributions and diurnal variations of particulate and dissolved dimethylsulfoxide (DMSOp, DMSOd) were studied in the surface water of the Yellow Sea and the Bohai Sea in June, 2011. The determination of DMSO was based on the DMS produced by NaBH4 reduction, which was analyzed using the purge-and-trap technique coupled with gas chromatographic separation and flame photometric detection. The concentrations of DMSOp and DMSOd ranged from 5.43 to 18.35 nmol x L(-1) and from 4.75 to 43.80 nmol x L(-1), respectively, with average values of (11.47 +/- 0.25) nmol x L(-1) and (13.42 +/- 0.58) nmol x L(-1). The results showed that no relationship was found between DMSOp and environmental factors such as chlorophyll a (Chl-a), temperature and salinity, whereas a positive correlation was observed between DMSOp/Chl-a and salinity, indicating that intracellular DMSO could act as a cryo-osmoregulator. A significant relationship was also found between DMSOd and dimethylsulfide (DMS), whereas there was no relationship between DMSOd and DMSOp or DMSOd and bacteria, implying that DMSOd in the surface water was produced mainly through the photochemical oxidation of DMS. In addition, both the DMSOp and DMSOd concentrations exhibited obvious diurnal variations with the higher values in the day time.

Control of oxidative posttranslational cysteine modifications: from intricate chemistry to widespread biological and medical applications.

Cysteine residues in proteins and enzymes often fulfill rather important roles, particularly in the context of cellular signaling, protein-protein interactions, substrate and metal binding, and catalysis. At the same time, some of the most active cysteine residues are also quite sensitive toward (oxidative) modification. S-Thiolation, S-nitrosation, and disulfide bond and sulfenic acid formation are processes which occur frequently inside the cell and regulate the function and activity of many proteins and enzymes. During oxidative stress, such modifications trigger, among others, antioxidant responses and cell death. The unique combination of nonredox function on the one hand and participation in redox signaling and control on the other has placed many cysteine proteins at the center of drug design and pesticide development. Research during the past decade has identified a range of chemically rather interesting, biologically very active substances that are able to modify cysteine residues in such proteins with huge efficiency, yet also considerable selectivity. These agents are often based on natural products and range from simple disulfides to complex polysulfanes, tetrahydrothienopyridines, α,ß -unsaturated disulfides, thiuramdisulfides, and 1,2-dithiole-3-thiones. At the same time, inhibition of enzymes responsible for posttranslational cysteine modifications (and their removal) has become an important area of innovative drug research. Such investigations into the control of the cellular thiolstat by thiol-selective agents cross many disciplines and are often far from trivial.

Revisiting the dissimilatory sulfate reduction pathway.

Sulfur isotopes in the geological record integrate a combination of biological and diagenetic influences, but a key control on the ratio of sulfur isotopes in sedimentary materials is the magnitude of isotope fractionation imparted during dissimilatory sulfate reduction. This fractionation is controlled by the flux of sulfur through the network of chemical reactions involved in sulfate reduction and by the isotope effect associated with each of these chemical reactions. Despite its importance, the network of reactions constituting sulfate reduction is not fully understood, with two principle networks underpinning most isotope models. In this study, we build on biochemical data and recently solved crystal structures of enzymes to propose a revised network topology for the flow of sulfur through the sulfate reduction metabolism. This network is highly branched and under certain conditions produces results consistent with the observations that motivated previous sulfate reduction models. Our revised network suggests that there are two main paths to sulfide production: one that involves the production of thionate intermediates, and one that does not. We suggest that a key factor in determining sulfur isotope fractionation associated with sulfate reduction is the ratio of the rate at which electrons are supplied to subunits of Dsr vs. the rate of sulfite delivery to the active site of Dsr. This reaction network may help geochemists to better understand the relationship between the physiology of sulfate reduction and the isotopic record it produces.

Improving the surface biocompatibility with the use of mixed zwitterionic self-assembled monolayers prepared by a proper solvent.

In this study, the mixed self-assembled monolayers (SAMs) containing the mixture of long-chain alkanethiol, SH(CH(2))(11)NH(2) and SH(CH(2))(10)SO(3)H, was prepared as a model surface to examine the interaction between the biological environment and artificial surface. The 10% (v/v) NH(4)OH ethanolic solution and DMSO were chosen as the solvents for the preparation of these mixed SAMs and the "solvent effect" was discussed. X-ray photoelectron spectroscopy (XPS) has indicated that -SO(3)H/-NH(2) mixed SAMs formed from 10% (v/v) NH(4)OH ethanolic solution were surface "-SO(3)H poor", while a nearly equivalent amount of surface -SO(3)H functionality was presented on the mixed SAMs formed from DMSO. This has resulted from the different solvation capability between solvent molecules and the alkanethiol. Such solvent effects were also reflected in various surface properties such as surface wettability and surface zeta potential. The mixed SAMs formed from DMSO were more surface hydrophilic and less negatively surface charged than from 10% (v/v) NH(4)OH ethanolic solution. In addition, these mixed SAMs formed from DMSO exhibited the least amount of protein adsorbed as well as a better platelet compatibility than its counterpart from 10% (v/v) NH(4)OH ethanolic solution. These findings indicated that choosing a proper solvent for mixed zwitterionic SAM can greatly affect its surface properties and biocompatibility, such as to form a surface with near neutrality for reducing protein adsorption and subsequent platelet adhesion and activation.

[Feasibility of sewage sludge used as filling material in permeable reactive barrier].

Permeable reactive barriers (PRB) have been used widely as an alternative technique to treatment of acid mine drainage (AMD). Selection of the appropriate filling materials is the most important procedure to application of this treatment. Batch adsorption tests and bacteria culture batch tests were conducted to assess the possibility of sewage sludge served as filling material for PRB. Results from batch adsorption tests showed that the maximum adsorption capacities of the sewage sludge were 13.62 mg x g(-1) (Zn2+) and 15.60 mg x g(-1) (Cd2+). Bacteria culture batch tests indicated that SO4(2-) concentrations in reactors decreased from initial concentrations of 700 mg x L(-1) to below 300 mg x L(-1). Sulfate removal efficiency ranged from 60% to 70%. Fe and heavy metals, including Zn and Cd, were removed completely in two reactors. This study suggested that sewage sludge is a suitable filling material for PRB.

[Effect of design and operation parameters on volatile alkylsulfides removal in subsurface constructed wetlands].

A pilot-scale subsurface constructed wetland wastewater treatment system was sampled for one year to study the effects of bed aspect ratio, substrate medium size, water depth, HLR (hydraulic loading rate) and temperature (season) on removal of volatile alkylsulfides such as DMS (dimethylsulfide) and DMDS (dimethyldisulfide). The yearly experimental results demonstrated that the system showed good performance for DMS and DMDS removal in wastewater under different HLR ranging from 12 cm x d(-1) to 86 cm x d(-1). The system could remove 86% of DMS, and 95% of DMDS, respectively. ANOVA statistical analysis shows that HLR and temperature (season) are major factors controlling the system performance for the target analytes. According to ANOVA test, the HLR caused significant differences (p < 0.01) on the average DMS effluent concentrations, and temperature (season) caused significant differences (p < 0.01) on the average DMS and DMDS effluent concentrations. However, bed aspect ratio, substrate medium size and water depth did not cause significant differences (p > 0.05) on the average DMS and DMDS effluent concentrations. A survey of dissolved oxygen and ORP indicates that the constructed wetlands system showed strong reduced condition. On the basis of investigations of electron acceptors (such as SO4(2-), NO3- and NO2-) and dissolved organic pollutants (such as TOC and acetic acid) concentrations along with the length of constructed wetlands, it can be concluded that sulfate reduction and methanogenisis were estimated to be significant for DMS and DMDS removal in constructed wetland beds.