Sulfur-containing Organic Compounds Research Articles

Superoxide Photoproduction from Wetland Plant-Derived Dissolved Organic Matter: Implications for Biogeochemical Impacts of Plant Invasion.

Although the impacts of exotic wetland plant invasions on native biodiversity, landscape features, and carbon-nitrogen cycles are well appreciated, biogeochemical consequences posed by ecological competition, such as the heterogeneity of dissolved organic matter (DOM) from plant detritus and its impact on the formation of reactive oxygen species, are poorly understood. Thus, this study delves into O2•- photogeneration potential of DOM derived from three different parts (stem, leaf, and panicle) of invasive Spartina alterniflora (SA) and native Phragmites australis (PA). It is found that DOM from the leaves of SA and the panicles of PA has a superior ability to produce O2•-. With more stable aromatic structures and a higher proportion of sulfur-containing organic compounds, SA-derived DOM generally yields more O2•- than that derived from PA. UVA exposure enhances the leaching of diverse DOM molecules from plant detritus. Based on the reported monitoring data and our findings, the invasion of SA is estimated to approximately double the concentration of O2•- in the surrounding water bodies. This study can help to predict the underlying biogeochemical impacts from the perspective of aquatic photochemistry in future scenarios of plant invasion, seawater intrusion, wetland degradation, and elevated solar UV radiation.

Microbial Conversion of Sulfur-Containing Compounds Contributed the Natural Biodegradation of Bituminous Coals

Microorganisms can affect coal biodegradation by driving elemental biogeochemical cycling. A detailed description of the sulfur conversion process led by indigenous bacteria during coal degradation is important. This study obtained sulfur-containing compounds conversion bacteria through indoor enrichment and conducted anaerobic culture experiments using coal supplemented with enriched bacteria. The study showed that the addition of enriched bacteria changed the microbial composition, particularly the microbial groups within Pseudomonadota and Bacillota. In addition, the sulfur-containing compounds conversion bacteria increased the pore volume and specific surface area of micropores (<10 nm) and transition pores (10–100 nm), as well changed the content of sulfur-containing organic components including polypeptides, aromatic compounds, alkyl compounds, and thiazoles. The genera related to inorganic sulfur conversion were mainly belonging to Bacillota and Actinomycetota. Additionally, functional genera that can degrade sulfur-containing organic compounds of dibenzothiophenes through the ring-opening of benzene rings were found within Pseudomonadota, Bacillota and Actinomycetota. In summary, organic sulfur-related Pseudomonadota, Bacillota and Actinomycetota and inorganic sulfur-related Bacillota and Actinomycetota detected in this study could accelerate the sulfur-containing compounds conversion and ultimately increase micropores in coal, and this holds great significance for understanding the biogeochemical cycling process of coal.

Photocatalytic desulfurization of gas condensate using zinc diacetate and cadmium diacetate liquid catalysts

This inquiry studied the application of photocatalytic desulfurization as an effective method for removing sulfur-containing organic compounds from gas condensate extracted from oil wells. To this end, cadmium diacetate and zinc diacetate compounds were prepared as the liquid catalysts. Then their structures were confirmed and their properties were determined by common methods, including FTIR, NMR, and UV. Subsequently, their performances as catalysts were investigated by an optical technique for the desulfurization process. Accordingly, the study used a photoreactor equipped with a 250 W mercury ultraviolet lamp with a maximum wavelength of 365 nm, and investigated and optimized the effect of the ratios of the influencing parameters on the total sulfur removal efficiency. These included the ratios of fuel to photocatalyst, H2O2, and acetonitrile. Ratios of 1:2:3:2 and 1:3:2:1 (fuel: catalyst: oxidant: solvent) of zinc and cadmium diacetate led to 93.5 % and 87.1 % reduction of the total sulfur content, respectively, after 60 min since the exposure process. Also, under sunlight, the total sulfur removal was 67.0 % for the Zn diacetate and 42.0 % for Cd diacetate. Liquid diacetate photocatalysts were successfully recycled over five cycles with only a maximum of 10 % reduction in efficiency. The kinetics of the systems studied were evaluated under optimal conditions and it was found that both systems fit the pseudo-first order model with rate constants of 0.148 min−1 and 0.098 min−1, respectively. In the final step, some physicochemical properties of the desulfurized sample crucial in evaluation of fuel quality were determined under optimal conditions and compared with the properties of the original sample. The results indicated that the liquid photocatalysts used in the experiment increased the quality of the fuel by changing its important indicators by reducing its freezing point in addition to increasing its cetane number.

The Antioxidant Properties of Glucosinolates in Cardiac Cells Are Independent of H2S Signaling.

The organic sulfur-containing compounds glucosinolates (GSLs) and the novel gasotransmitter H2S are known to have cardioprotective effects. This study investigated the antioxidant effects and H2S-releasing potential of three GSLs ((3E)-4-(methylsulfanyl)but-3-enyl GSL or glucoraphasatin, 4-hydroxybenzyl GSL or glucosinalbin, and (RS)-6-(methylsulfinyl)hexyl GSL or glucohesperin) in rat cardiac cells. It was found that all three GSLs had no effect on cardiac cell viability but were able to protect against H2O2-induced oxidative stress and cell death. NaHS, a H2S donor, also protected the cells from H2O2-stimulated oxidative stress and cell death. The GSLs alone or mixed with cysteine, N-acetylcysteine, glutathione, H2O2, iron and pyridoxal-5'-phosphate, or mouse liver lysates did not induce H2S release. The addition of GSLs also did not alter endogenous H2S levels in cardiac cells. H2O2 significantly induced cysteine oxidation in the cystathionine gamma-lyase (CSE) protein and inhibited the H2S production rate. In conclusion, this study found that the three tested GSLs protect cardiomyocytes from oxidative stress and cell death but independently of H2S signaling.

High efficiency extraction oxidation desulfurization of model liquid fuel catalyzed by MIL-101(Fe) supported peroxo-polyoxometalates

In this work, the encapsulating peroxo-polyoxometalate in the mesoporous of metal-organic framework (MIL-101(Fe)) to synthesize composite according to the principle of host-guest matching. The structure of the host-guest composite was analyzed by a variety of methods, and the catalytic activity for desulfurization was investigated under mild conditions. The composites combine the advantages of peroxo-polyoxometalate (high efficiency) and MIL-101(Fe) (good recyclability and high porosity), showing synergistic effect between host and guest. The sulfur-containing organic compounds in simulated liquid fuel can be almost completely removed under the catalysis of PW4@MIL-101(Fe). The catalyst PW4@MIL-101(Fe) can be reused for 10 times without prominent decrease in desulfurization activity, indicating that it has good reusability due to the confinement effect between the window size of MIL-101(Fe) and molecular size of PW4. In addition, several control experiments and electron spin resonance experiment were researched to explore the possible mechanism, and the results show that the active component in the catalyst can promote the decomposition of H2O2 into ·OH and thus accelerate the desulfurization reaction. This work discloses a facile and environmentally friendly method to prepare the "host-guest matching" catalyst with high activity and stable reusability, which provides ways for further developments in heterogeneous catalyst based on POM and MOF.

Genomic analyses reveal a low-temperature adapted clade in Halorubrum, a widespread haloarchaeon across global hypersaline environments

BackgroundCold-adapted archaea have diverse ecological roles in a wide range of low-temperature environments. Improving our knowledge of the genomic features that enable psychrophiles to grow in cold environments helps us to understand their adaptive responses. However, samples from typical cold regions such as the remote Arctic and Antarctic are rare, and the limited number of high-quality genomes available leaves us with little data on genomic traits that are statistically associated with cold environmental conditions.ResultsIn this study, we examined the haloarchaeal genus Halorubrum and defined a new clade that represents six isolates from polar and deep earth environments (‘PD group’ hereafter). The genomic G + C content and amino acid composition of this group distinguishes it from other Halorubrum and the trends are consistent with the established genomic optimization of psychrophiles. The cold adaptation of the PD group was further supported by observations of increased flexibility of proteins encoded across the genome and the findings of a growth test.ConclusionsThe PD group Halorubrum exhibited denser genome packing, which confers higher metabolic potential with constant genome size, relative to the reference group, resulting in significant differences in carbon, nitrogen and sulfur metabolic patterns. The most marked feature was the enrichment of genes involved in sulfur cycling, especially the production of sulfite from organic sulfur-containing compounds. Our study provides an updated view of the genomic traits and metabolic potential of Halorubrum and expands the range of sources of cold-adapted haloarchaea.

Allicin Alleviated LPS-Induced Mastitis via the TLR4/NF-κB Signaling Pathway in Bovine Mammary Epithelial Cells.

Dairy farming is the most important economic activity in animal husbandry. Mastitis is the most common disease in dairy cattle and has a significant impact on milk quality and yield. The natural extract allicin, which is the main active ingredient of the sulfur-containing organic compounds in garlic, has anti-inflammatory, anticancer, antioxidant, and antibacterial properties; however, the specific mechanism underlying its effect on mastitis in dairy cows needs to be determined. Therefore, in this study, whether allicin can reduce lipopolysaccharide (LPS)-induced inflammation in the mammary epithelium of dairy cows was investigated. A cellular model of mammary inflammation was established by pretreating bovine mammary epithelial cells (MAC-T) with 10 µg/mL LPS, and the cultures were then treated with varying concentrations of allicin (0, 1, 2.5, 5, and 7.5 µM) added to the culture medium. MAC-T cells were examined using RT-qPCR and Western blotting to determine the effect of allicin. Subsequently, the level of phosphorylated nuclear factor kappa-B (NF-κB) was measured to further explore the mechanism underlying the effect of allicin on bovine mammary epithelial cell inflammation. Treatment with 2.5 µM allicin considerably decreased the LPS-induced increase in the levels of the inflammatory cytokines interleukin-1β (IL-1β), interleukin-6 (IL-6), interleukin-8 (IL-8), and tumor necrosis factor-α (TNF-α) and inhibited activation of the NOD-like receptor protein 3 (NLRP3) inflammasome in cow mammary epithelial cells. Further research revealed that allicin also inhibited the phosphorylation of inhibitors of nuclear factor kappa-B-α (IκB-α) and NF-κB p65. In mice, LPS-induced mastitis was also ameliorated by allicin. Therefore, we hypothesize that allicin alleviated LPS-induced inflammation in the mammary epithelial cells of cows probably by affecting the TLR4/NF-κB signaling pathway. Allicin will likely become an alternative to antibiotics for the treatment of mastitis in cows.

Mesoporous zeolite Beta supported Ni nanoparticles for the catalytic hydroconversion of extraction portion from Jinjitan subbituminous coal to cycloalkanes

The catalytic hydroconversion (CHC) of heavy carbon organic species (HCOSs) to cycloalkanes represents an importantly used chemical industry process due to the wide applicability of the resulting products in energy and fine chemistry. Despite the existing conventional catalysts applied to the CHC of HCOSs, the development of highly active bifunctional Ni-based heterogeneous catalysts for this process is still a challenge. Therefore, we show that the modified deposition–precipitation of nickel (II) nitrate on hydrothermally synthesized mesoporous zeolite Beta (MZB) prepares a Ni/MZB catalyst with a through-crosslinking mesopore structure and uniformly disperse Ni nanoparticles (NPs) at rough MZB crystal surface. The 10%Ni/MZB (10% Ni loading), in the presence of exposing on amount of accessible Lewis acid sites (LASs) and attaching Ni NPs by chemical bonding from the silica matrix of MZB skeleton, exhibits excellent activity to promote the CHC of all kind of aromatic rings and heteroatom-containing species, including chain alkanes, arenes, oxygen-containing organic compounds (OCOCs), nitrogen-containing organic compounds (NCOCs), and sulfur-containing organic compounds (SCOCs), to produce cycloalkanes and hydroarenes under mild conditions. Interestingly, density functional theory (DFT) calculations indicate that the transfer of biatomic active hydrogen (H…H) and heterogenous H+ from 10%Ni/MZB plays important roles during the CHC of diphenoxybenzene (DPOB). After being recycled 4 times, 10%Ni/MZB is still maintains high activity for CHC of DPOB under mild conditions.

Benzonaphthothiophene: Molecular Indicators for Thermal Maturity

Benzonaphthothiophenes (BNTs) were firmly identified in coals by comparison with retention indices reported in the literature. The thermodynamic stabilities of BNTs were calculated by quantum chemical computations, and their stability sequence is as follows: [2,1]BNT > [2,3]BNT > [1,2]BNT. The BNT isomers are ubiquitous in coal samples from the Xihu Depression and the Ordos Basin. This study reveals the effects of thermal maturity on the distributions of BNTs in coals, where the relative abundances of [1,2]BNT and [2,3]BNT to [2,1]BNT were observed to be mainly controlled by thermal maturation conditions. Combining with theoretical calculations of thermodynamic stability, two benzonaphthothiophene maturity indicators, defined as BNTR-1 ([2,1]BNT/[2,3]BNT) and BNTR-2 ([2,1]BNT/([1,2]BNT + [2,3]BNT)), were proposed. Two preliminary calibrations of BNTR-1 and BNTR-2 against measured vitrinite reflectance (%Ro) were established, and the relationships are as follows: %Rc = 5.5 × BNTR-1/100 + 0.5 (%Ro >0.9) and %Rc = 15 × BNTR-2/100 + 0.5 (%Ro > 0.9), respectively. BNTR-1 and BNTR-2 have good correlations with the widely used molecular maturity parameters. The good correlations with vitrinite reflectance and maturity parameters suggest that BNTR-1 and BNTR-2 are useful indicators in evaluating the maturity for sedimentary organic matter at high levels of thermal stress. The accuracy of the BNT ratio ([2,1]BNT/[1,2]BNT) must be kept in mind when it is used as a migration tracer of oil generated at a high thermal maturation stage. There is no clear trend for the absolute concentrations of BNTs with increasing pristane/phytane and gammacerane/C30 hopane values, suggesting that the redox conditions and water salinity during deposition may have little influence on the generation of BNTs. This study can expand the understanding of the distribution and geochemical significance of complex sulfur-containing organic compounds in sedimentary organic matter.

Thermodynamics of hydrogen sulfide adsorption in NaX zeolite

Sulfur-containing organic and inorganic compounds are the main harmful component of natural gas and oil, as well as products of their processing. Since sulfur compounds have acidic properties, their content leads to corrosion of technological parts in production processes. The content of hydrogen sulfide in the transported gas should not exceed 20 mg/m3. In Uzbekistan, motor vehicles run mainly on liquefied natural gas. Sulfur compounds in natural gas corrode gas cylinders, resulting in an explosion. If synthetic zeolites are used in manufacturing processes, as well as in small gas production, process degradation will be prevented. Synthetic zeolites are widely used in various industrial production processes due to their high sorption properties. This study makes it possible to study the localization and sorption structure of sulfur compounds in supercavities of zeolites of the faujasite type. The adsorption of hydrogen sulfide on NaX zeolite was carried out in a high vacuum adsorption unit. Based on the results obtained, the differential heat of adsorption, isotherm, entropy, and thermal equilibrium time (thermokinetics) were calculated.

Oxidative Desulfurization of Real High-Sulfur Diesel Using Dicarboxylic Acid/H2O2 System

From the perspective of pollution, economics, and product quality, it is very important to find an efficient way to minimize the sulfur content of petroleum products such as gasoline and diesel. In this work, an effective, inexpensive, and simple oxidative desulfurization system based on hydrogen peroxide activation by three dicarboxylic acids which have different carbon numbers (i.e., malonic acid, succinic acid, and glutaric acid) was utilized for the desulfurization of a real diesel sample with high organic sulfur-containing compounds. The desulfurization process was based on the oxidation of sulfur compounds in diesel fuel to the corresponding sulfones followed by acetonitrile extraction of the sulfones. To select the optimal experimental conditions, the effects of several parameters, including temperature, catalyst H2O2 dosages, and treatment time, were investigated. The results showed that the developed system was effective in desulfurizing real diesel fuel with high sulfur content. With an initial total sulfur content of about 8104 mg/L, the desulfurization rate from the diesel sample reached more than 90.9, 88.9, and 93%, using malonic acid, succinic acid, and glutaric acid, respectively. The optimum parameters such as reaction temperature, reaction time, H2O2 (50 w/w%), and carboxylic acid dosage for oxidative desulfurization were determined to be 95 °C, 6 h, 10 mL, and 0.6 g, respectively. The conversion of refractory sulfur compounds into extractable sulfone forms was verified using gas chromatography. Moreover, the kinetic study confirmed that the designed reaction system follows the pseudo-first-order kinetic model.

Constructing artificial solid electrolyte interphase by facile chemical reaction for stable lithium metal anodes

Lithium metal is considered one of the most promising anode materials because of its high theoretical capacity and the lowest electrode potential, but practical application is hampered by high reactivity and volume variation in circulation. As a key component, the artificial solid electrolyte interphase (SEI) is designed to effectively stabilize the lithium anode. Here, the chemical reaction between dimethyl sulfoxide (DMSO) and lithium is accelerated in the presence of potassium hydroxide (KOH). The sulfur-containing organic compounds, lithium sulfate (Li2SO4), lithium hydroxide (LiOH) and other favorable components are introduced into SEI, which enable the modified lithium metal anode to have lower interfacial impedance, higher lithium ion transference number, and more uniform Li-ion deposition. The assembled Li-Li symmetric battery realizes a stable cycle of more than 800 h at a current density of 0.5 mA cm−1 and an areal capacity density of 1 mAh cm−1. The full cell coupled with LiNi0.6Co0.2Mn0.2O2 (NCM622) still maintains 113 mAh g−1 discharge capacity with 63% capacity retention rate after 400 cycles at a current density of 0.5 C. The simple construction of artificial SEI strategy of this study provides an effective strategy for LMBs with superior electrochemical performance.

Sulfate-TOR signaling controls transcriptional reprogramming for shoot apex activation.

Plants play a primary role for the global sulfur cycle in the earth ecosystems by reduction of inorganic sulfate from the soil to organic sulfur-containing compounds. How plants sense and transduce the sulfate availability to mediate their growth remains largely unclear. The target of rapamycin (TOR) kinase is an evolutionarily conserved master regulator of nutrient sensing and metabolic signaling to control cell proliferation and growth in all eukaryotes. By tissue-specific Western blotting and RNA-sequencing analysis, we investigated sulfate-TOR signal pathway in regulating shoot apex development. Here, we report that inorganic sulfate exhibits high potency activating TOR and cell proliferation to promote true leaf development in Arabidopsis in a glucose-energy parallel pathway. Genetic and metabolite analyses suggest that this sulfate activation of TOR is independent from the sulfate-assimilation process and glucose-energy signaling. Significantly, tissue specific transcriptome analyses uncover previously unknown sulfate-orchestrating genes involved in DNA replication, cell proliferation and various secondary metabolism pathways, which largely depends on TOR signaling. Systematic comparison between the sulfate- and glucose-TOR controlled transcriptome further reveals that TOR kinase, as the central growth integrator, responds to different nutrient signals to control both shared and unique transcriptome networks, therefore, precisely modulates plant proliferation, growth and stress responses.

Particle characterization and quantification of organic and inorganic compounds from Chinese and Iranian aerosol filter samples using scanning laser desorption/ionization mass spectrometry

Besides their influence on climate and cloud formation, many organic and inorganic substances in aerosol particles pose a risk to human health. Namely, polycyclic aromatic hydrocarbons (PAH) and heavy metals are suspected to be carcinogenic or acutely toxic. The detection and quantification of such compounds is difficult if only small amounts of particulate matter (PM) are available. In addition, filter samples are often complex and time-consuming to prepare for chromatographic measurements and elemental analysis. Here, we present a method based on high-resolution atmospheric pressure laser desorption ionization mass spectrometry imaging (AP-LDI-MSI) and statistical analysis which allows the analysis and characterization of very small sample quantities (< 30 µg) without any sample preparation. The power and simplicity of the method is demonstrated by two filter samples from heavily polluted mega cities. The samples were collected in Tehran (Iran) and Hangzhou (China) in February 2018. In the course of the measurement, more than 3200 sum formulae were assigned, which allowed a statistical evaluation of colocalized substances within the particles on the filter samples. This resulted in a classification of the different particle types on the filters. Finally, both megacities could be distinguished based on characteristic compounds. In the samples from Tehran, the number of sulphur-containing organic compounds was up to 6 times as high as the samples from Hangzhou, possibly due to the increasing efforts of the Chinese government to reduce sulphur emissions in recent years. Additionally, quantification of 13 PAH species was carried out via standard addition. Especially, the samples from Tehran showed elevated concentrations of PAHs, which in the case of higher-molecular-weight species (> m/z 228) were mostly more than twice as high as in Hangzhou. Both cities showed high levels of heavy metals and potentially harmful organic compounds, although their share of total particulate matter was significantly higher in the samples from Tehran. The pre-treatment of the samples was reduced to a minimum with this method, and only small amounts of particles were required to obtain a comprehensive picture for a specific filter sample. The described method provides faster and better control of air pollution in heavily polluted megacities.Graphical abstract

Unraveling the Structure and Surface Chemistry of the Phosphosulfide Phase Formed on Ni2P under Hydrodesulfurization Reaction Conditions: A DFT Study

There is experimental evidence that the actual active phase of the Ni2P catalyst under hydrodesulfurization (HDS) reaction conditions is a nickel phosphosulfide phase formed on the catalyst surface. Combining DFT calculations and an atomistic thermodynamic approach, we investigated the possibility of sulfur adsorption as well as the replacement of surface phosphorus by sulfur on the (0001) and (1010) surfaces of the Ni2P catalyst. Our DFT calculations showed that sulfur could replace up to 100% of the surface phosphorus under hydrodesulfurization (HDS) reaction conditions. We identify that possible sulfur adsorption sites on both surface terminations are arrangements of Ni trimers (Ni3 sites). We found that only the phosphosulfide phase formed on the (1010)-AB_Ni2P surface termination has coordinatively unsaturated Ni atoms available for the adsorption of organic sulfur-containing compounds. Our results suggest that the phosphosulfide phase formed on the (1010)-AB_Ni2P termination and not on the (0001)-Ni3P2 termination could be responsible for the high HDS activity of the Ni2P catalyst. Upon the replacement of P by S, the Ni3 sites undergo tensile strain, and their reactivity toward S adsorption is modified by the imposed strain. We found that the Ni–Ni bond distance is an important parameter in describing the HDS activity of the Ni2P catalyst. By analyzing the relationship among the ensemble, ligand, and strain effects, we were able to provide a better understanding of the promoting effect introduced by the formation of the nickel phosphosulfide phase.

Exceptional structure flexibility and adaptive catalytic desulfurization of a cyclic decanuclear polyoxoalkoxyvanadate (Ⅲ)

Removal of notorious organic sulfur-containing compounds to produce low-sulfur-content diesel is of great significance in developing modern industry and addressing environmental protection, but the key challenge is to seek recyclable heterogeneous catalysts with high efficiency. Herein, an intelligent regulation structural polyoxometalate-based hybrid compound with a ten-membered ring cluster has been synthesized via facile solvothermal method, formulated as [VIII10(μ2-OCH3)20(CH3CO2)10] (V10). Single crystal diffraction shows that every two adjacent vanadium ions in V10 are connected by methoxides and acetate group to construct a ten-membered wheel ring. It is noteworthy that the center of the ring can exhibit different opening and closing states through the disordered methoxy groups with rotational/oscillatory flexibility without disrupting the main structure of the ring, being analogous to IRIS stop of an optical camera. Notably, sulfur oxidation experiments indicated that V10 as heterogeneous catalyst displayed excellent catalytic activity, selectivity and stability for the catalytic oxidation of dibenzothiophene (DBT) at mild condition, which outperforms most of reported vanadium oxygen clusters. Benefiting from the multi-modal transformation of the inner ring structure, the catalyst can adaptively adjust the position of methoxy groups to make the sulfides more accessible to the active site, thus facilitating the conversion of DBT up to >99% in 40 ​°C. This study affords a novel perspective for the development of polyoxovanadates with better performance.

Sodium pyrosulfite inhibits the pathogenicity of Botrytis cinerea by interfering with antioxidant system and sulfur metabolism pathway

Grapes are cultivated worldwide and are favored by consumers for their delicious taste and nutritional value. Grey mould, caused by Botrytis cinerea, leads to considerable loss of postharvest grape fruit each year. Sulfur dioxide fumigation is widely used to inhibit grey mould of grape around the world, but there is still a lack of research on its antimicrobial mechanism, especially at molecular level. In present study, we explored the molecular mechanisms of sulfur dioxide against B. cinerea in vitro and in vivo, respectively, using the sulfur dioxide donor sodium pyrosulfite. The results indicated that sodium pyrosulfite treatment could inhibit the expression of genes in antioxidant system and sulfur metabolism pathway of B. cinerea. The down-regulated genes in sulfur metabolism were mainly involved in the process of assimilatory sulfate reduction, limiting the synthesis of sulfur-containing organic compounds. Furthermore, the expressions of several critical antioxidant genes were suppressed under the sodium pyrosulfite stress. The decrease of antioxidant capacity led to ROS accumulation in B. cinerea cell, resulting in the decrease of the survival rate. These results not only richen our understanding of the antimicrobial mechanisms of sulfur dioxide against B. cinerea at the molecular level, but also are beneficial for us to improve sulfur dioxide product in the future.

Study on deodorization effect of nano-attapulgite/CaCO3 carriers

In this study, in order to develop a new inorganic carrier to adsorb sulfur-containing organic compounds, the nano-attapulgite/CaCO3 carriers were developed with clay, nano-attapulgite, nano-calcium carbonate and silica as raw materials. The best raw material ratio of nano-attapulgite/CaCO3 carriers was optimized by single factor test and response surface experiments, and the deodorization effect of nano-attapulgite/CaCO3 carriers was further verified. The results showed that the optimal ratio of raw matrixes was 9.77 g of clay, 4.15 g of attapulgite, 2.80 g of nano-calcium carbonate, and 2.08 g of silica. The nano-attapulgite/CaCO3 carriers were prepared by calcining these mixed materials at 800 °C for 4 hours, and the water absorption was up to 31.78%. Besides, the deodorization effect of nano-attapulgite/CaCO3 carriers on fermented onion odor was as high as 45%, and the deodorization effect on rotten egg odor is up to 30%, indicating that the carrier has a high deodorization effect on sulfur compounds.

Исследование влияния микроволнового излучения на процесс десульфуризации мазута

Many chemical processes are intensified by microwave radiation. The main factor determining the usefulness of microwaves in most transformations of organic compounds is the reaction time reduction to obtain the maximum yield of the target product. The presence of sulphur in oil and petroleum products is detrimental to refining equipment, and also has a negative impact on the environment in the form of waste generated during refining. In this connection development of methods on removal of sulphurcontaining compounds from oil products and oil by their transformation (in particular oxidation) and subsequent removal is very significant. Oxidative desulphurisation of fuel oil takes up to several hours depending on the reagents used. In this work an attempt has been made to significantly reduce the duration of the process. Oxidation of sulphur-containing organic compounds in fuel oil under microwave radiation has been considered, which proceeds in the presence of an oxidizer (hydrogen peroxide) and a catalyst (titanium dioxide). It was found that the oxidative desulphurization of fuel oil at microwave radiation proceeds effectively and quickly within 1--5 min. The achieved degree of desulphurization is 66 % when exposed to microwave radiation for 5 min. The influence of the amount of water in the reaction mixture on the efficiency of oxidative desulphurization of fuel oil under microwave radiation has been studied; it was found that the optimum ratio of water : fuel oil was (1--1.2) : 1

Sulfane Sulfur Is a Strong Inducer of the Multiple Antibiotic Resistance Regulator MarR in Escherichia coli.

Sulfane sulfur, including persulfide and polysulfide, is produced from the metabolism of sulfur-containing organic compounds or from sulfide oxidation. It is a normal cellular component, participating in signaling. In bacteria, it modifies gene regulators to activate the expression of genes involved in sulfur metabolism. However, to determine whether sulfane sulfur is a common signal in bacteria, additional evidence is required. The ubiquitous multiple antibiotic resistance regulator (MarR) family of regulators controls the expression of numerous genes, but the intrinsic inducers are often elusive. Recently, two MarR family members, Pseudomonas aeruginosa MexR and Staphylococcus aureus MgrA, have been reported to sense sulfane sulfur. Here, we report that Escherichia coli MarR, the prototypical member of the family, also senses sulfane sulfur to form one or two disulfide or trisulfide bonds between two dimers. Although the tetramer with two disulfide bonds does not bind to its target DNA, our results suggest that the tetramer with one disulfide bond does bind to its target DNA, with reduced affinity. An MarR-repressed mKate reporter is strongly induced by polysulfide in E. coli. Further investigation is needed to determine whether sulfane sulfur is a common signal of the family members, but three members sense cellular sulfane sulfur to turn on antibiotic resistance genes. The findings offer additional support for a general signaling role of sulfane sulfur in bacteria.