Molecular Substances Research Articles

Algae-Laden Fouling Control by Gravity-Driven Membrane Ultrafiltration with Aluminum Sulfate-Chitosan: The Property of Floc and Cake Layer

Gravity-driven membrane (GDM) ultrafiltration is a promising water treatment method due to its low energy consumption and low maintenance. However, the low stable permeability in algae-laden water treatment is currently limiting its wider application. With the ultimate goal of increasing permeability, the aim of this study was to evaluate the effect of a composite coagulant of aluminum sulfate-chitosan (AS-CS) on the GDM filtration performance. In parallel tests with a single AS coagulant and without pre-coagulation, the analysis of membrane fouling resistance and the membrane fouling mechanism were evaluated. The results indicated that the AS-CS/GDM system can alleviate 23.74% and 58.80% membrane fouling, respectively, compared with AS/GDM and the GDM system. The AS-CS/GDM system can effectively remove humic-like substances having a molecular weight (MW) of 3–100 kDa, resulting in removal of 98.32% of algae cells and removal of 66.25% of dissolved organic carbon; the AS-CS/GDM system thereby improved the concentration of attached biomass on the membrane surface with the stronger biodegradability of organic matters. The application of AS-CS pre-coagulation in the GDM process could enhance the proliferation of microorganisms and the removal of low molecular weight humic-like substances. Therefore, the AS-CS/GDM system is a potentially important approach for algae-laden water treatment.

Characterisation of Recombinant Human Erythropoietin Obtained from CHOpE—Erythropoietin Producing Strain of Chinese Hamster Ovary Cells

Development and implementation in clinical practice of recombinant human erythropoietins (rhEPOs) remain a priority task today. Additional studies were performed in order to obtain clinical trial authorisation for rhEPO tablets for oral use. The studies were aimed to demonstrate the suitability of the erythropoietin producer strain based on Chinese hamster ovary cells (CHOpE) for the production of rhEPO, and the compliance of the substance characteristics with the requirements for erythropoietin (EPO).The aim of the study was to characterise the rhEPO substance obtained from the CHOpE strain cells in accordance with the requirements for EPO.Materials and methods: the rhEPO substance was obtained by culturing the strain of Chinese hamster ovary cells—CHOpE. The expression construct of the producer strain was evaluated using methods for determination of nucleotide and amino acid sequences. The Sanger method was used to perform sequencing of the nucleotide sequence encoding the human EPO gene. The amino acid sequences of the rhEPO molecule C- and N-termini were determined by the Edman method. The copy number of the EPO gene in CHOpE cells was determined by real-time polymerase chain reaction. The properties of the rhEPO substance were evaluated in accordance with the requirements for EPO. Isoelectric focusing, peptide mapping, and polyacrylamide gel electrophoresis were used for identification of the rhEPO substance. The ratio of isoform composition was determined by capillary electrophoresis. Dimer impurities and high molecular weight related substances were determined by high-pressure liquid chromatography. The content of protein and residual nucleic acids was determined by spectrophotometry. The concentration of the rhEPO substance was assessed by enzyme immunoassay.The results of the study confirmed genetic stability of the CHOpE producer strain and demonstrated identity of N- and C-terminal amino acid sequences of the rhEPO molecule to those of the natural EPO. The CHOpE producer strain was used to obtain a rhEPO substance which is homogenous and does not contain impurities of EPO oligomeric forms. Dimers and high molecular weight related substances account for less than 0.5%. The rhEPO molecular weight ranges from 32 to 38 kDa, and the isoelectric point is within 2.8—4.15. The study identified the peaks of isoforms 1–8, the isoform composition of the rhEPO substance corresponds to that of EPO. It was determined that 1 mol of the substance contains 13.75 mols of sialic acids.Conclusions: the study confirmed the suitability of the CHOpE producer strain for the production of rhEPO. The obtained rhEPO substance meets requirements for EPO.

Molecular docking of potential cytotoxic alkylating carmustine derivatives 2-chloroethylnitrososulfamides analogues of 2-chloroethylnitrosoureas

The objective of this work was the molecular modelling by bio-isostery of 2-chloroethylnitrosoureas CENU into 2-chloroethylnitrososulfamides CENS derived from Carmustine. We evaluated the pharmacodynamic profile of the new chemical class by studying molecular docking using innovative software. Good molecular docking scores were obtained through Auto-dock vina of the PyRx 0.8 software, the energy of the complexes formed (Target-Ligand) during the interaction varies from - 5,400 to -5,700 Kcal/mol, the total average between the 45 conformers is −5,213 Kcal/mol. The results were validated by Auto-dock vina 1.5.6 in collaboration with the Molecular Chemistry and Natural Substances Laboratory at the Meknes Faculty of Science - Morocco, a range of -4,900 to -5,100 Kcal/mol was noted for CENS complexes derived from Carmustine with the 2DND target, reflecting a better CENS chemical affinity to the biological target and the stability of the ligand-DNA complex, compared with the analogue reference Carmustine with a score of - 4,700 Kcal/mol. By superimposing the results of molecular docking, analysis of data from the study of electrophilia based on load transfer ECT and publications on CENS, we can predict that inter-strand crosslink is likely to occur between the Guanine dG22 of strand B and the Cytosine dC3 of strand A, located in the poly dA-poly dT segment end within the narrow minor groove of the DNA target (2DND). The molecular docking study was a preliminary approach to understand the therapeutic mode of action of CENS. Communicated by Ramaswamy H. Sarma

Nerve and Blood Vessel Wiring in Endometriotic Peritoneal Lesions

Detection of unique nerve fibres in the endometrium of women with endometriosis and subsequently in their peritoneal lesions has led to increased interest in studying their relationship with infertility and pain. Blood vessels and nerves fibres course throughout the body in an orderly pattern, often alongside one another. Although superficially distinct, the mechanisms involved in wiring neural and vascular networks seem to share similarities. We found that nerve fibres and blood vessels traverse the endometriotic peritoneal tissue in slightly different ways with variations in length densities (Lv), branch point density (Bv), segment length between branch points (Lv/Bv) and capillary radial diffusion distance r(diff). The capillary radial diffusion distance r(diff) and the spatial co-localisation distance in conjunction with nerve fibres fell within range for the facilitation of the physiological diffusion and transfer of molecular substances and the transmission of electrical signals to co-ordinate tasks within the endometriotic peritoneal lesion.Biological systems exist and operate in a three-dimensional environment and blood vessels and nerve trunks often travel in close apposition through many tissues; therefore, it was a priority to assess (CD31+) blood vessel and (PGP9.5+) nerve fibre three-dimensional structural features from qualitative and quantitative perspectives in peritoneal endometriotic lesions. Utilising laser scanning confocal microscopy allowed for considerable precision in the study of endometriotic peritoneal lesion blood vessel and nerve fibre co-localisation and three-dimensional relationships.

Evaluation of Dissolved Organic Matter Removal Characteristics in GAC Adsorption Process in Drinking Water Treatment Process using LC-OCD-OND

Objectives:In this study, we used liquid chromatograph-organic carbon detector-organic nitrogen detector (LC-OCD-OND) to evaluate adsorption and breakthrough characteristics of NOM fractions (biopolymers (BP), humic substances (HS), building blocks (BB) and low molecular weight organic substances (LMW-O)) according to the various characteristics of the different materials of granular activated carbons (GACs).Methods:Breakthrough characteristics, adsorption capacity and partition coefficients were evaluated by NOM fractions (BP, HS, BB, and LMW-O) using a lab-scale GAC adsorption column filled with coal-, coconut- and wood-based GAC. The GAC column test was operated with 10 minutes empty bed contact time (EBCT). The pore characteristics of each GAC were evaluated using an automated gas sorption analyzer (Autosorb iQ3, Quantachrome, USA) and the concentrations of NOM fractions in the influent and effluent were analyzed using chromatography LC-OCD-OND (Model 8, DOC-Labor, Germany).Results and Discussion:NOM adsorption capacity was evaluated for different materials of laboratory scale GAC adsorption column test. To study the adsorption behavior of individual NOM fractions according to the operation time, NOM was fractionated into BP, HS, BB and LMW-O by LC-OCD-OND, and the individual NOM fractions were quantified. Higher MW like BP was not adsorbed to GAC, in contrast, HS, BB, and LMW-O were well removed during the initial operation period, the concentrations in the effluent gradually increased as increase the operation period until reaching to the pseudo steady-state. Poor removal of BP in GAC adsorption may be a result of blocking the pores with large MW BP and hinder the access to the pores. However, in the case of HS, BB, and LMW-O, as the molecular size decreased, these organic matters easily access to the pores inside of GAC. It was confirmed through the partition coefficient that the adsorption capacity of these NOM fractions increased in proportion to the MW. In addition, in order to achieve a high NOM removal efficiency in the GAC adsorption process, not only the specific surface area, pore volume, and pore width of the GAC must be large, but also the pH<sub>zpc</sub> must be higher than the neutral pH level.Conclusions:In order to achieve a high NOM removal efficiency in the GAC adsorption process, not only the specific surface area, pore volume, and pore width of the GAC must be large, but also the pH<sub>zpc</sub> must be higher than the neutral pH level. In addition, in the NOM fractions, BP were not adsorbed to GAC, while the adsorption capacity of the remaining NOM fractions increased as the MW of the NOM fractions decreased. LMW-O was the most adsorbed, followed by BB, HS and BP. BP and HS play an important role in the membrane fouling that are introduced a lot into domestic and foreign water treatment plants. This study showed that the BP was not removed by the adsorption mechanism of the GAC process. In addition, HS was adsorbed and removed at the beginning of the operation, but the adsorption capacity of HS decreased rapidly as the operation period increased compared to other NOM fractions. Therefore, the GAC adsorption process is not expected to be an effective pre-treatment technology for reducing membrane foulants. Previous studies showed that the yields of DBPs (µmol･DBP/µmol･C) in the high MW humic and low MW non-humic fractions are similar. Therefore, it is suggested that the GAC adsorption process is more effective for DBP precursor control in water containing a larger percentage of LMW NOM.

Alleviation of Field Low-Temperature Stress in Winter Wheat by Exogenous Application of Salicylic Acid

Low temperature in later spring severely limits plant growth and causes considerable yield loss in wheat. In this study, the impacts of exogenous salicylic acid (SA) on plant growth, grain yield and key physiological parameters of wheat plants were investigated under field low-temperature conditions using a field air temperature control system (FATC). The results showed that low-temperature stress significantly decreased leaf net photosynthetic rate, plant height and biomass production of wheat plants at the jointing stage, resulting in a reduction in grain yield. Moreover, the growth period of wheat plants was prolonged by low-temperature stress. However, SA-treated plants significantly improved the photochemical efficiency of photosystem II, accumulation of osmo-protectants, activities of enzymatic antioxidants, and pool of non-enzymatic low molecular substances compared with non-SA-treated plants under low-temperature stress. Pretreatment with SA effectively alleviated low-temperature-induced reduction in leaf net photosynthetic rate, plant height, biomass production and grain yield as well as prolonging of growth period of wheat plants. However, SA-treated plants had no significant effects on the expression levels of cold-responsive genes compared with non-SA-treated plants under low-temperature stress. Our results demonstrated that exogenous application of SA is an appropriate strategy for wheat to resist late spring low-temperature stress under field conditions.

Estimation and optimization of exopolysaccharide production from rice rhizospheric soil and its interaction with soil carbon pools

Exopolysaccharides (EPS) the high molecular weight microbial substances play an important role in enhancing soil aggregation as well as maintaining water holding capacity around the rhizosphere. Therefore, looking into the fact that rice is one of the important food crops for most of the people of the world and the ability of EPS to increase the uptake of nutrients by plants and protect from drought stress. The present investigation was carried out to study the EPS production by bacteria isolated from rice cultivar Naveen with four treatments viz., aerobic (−5 kPa), saturation (0 kPa), submerged (2 cm standing water) and control (without any water treatment) and their interaction with soil labile carbon pools. Soil (0–15 cm depth) was collected from panicle initiation stage of the crop growth to isolate EPS producing bacteria. Different parameters like microbial biomass carbon (MBC), readily mineralizable carbon (RMC) and organic carbon (OC) alongwith total and colloidal EPS were estimated. The total and colloidal EPS increased 26.0% and 9.0% among the treatments over saturation. The MBC, RMC and OC were found to increase 30.0%, 19.0% and 4.0% among the treatment over saturation. These findings indicated a positive correlation between carbon pools and total and colloidal EPS production. Similarly, in this study, 22 EPS producing bacteria were isolated from the rice rhizospheric region and amongst 4 isolates were found to tolerate maximum level of water stress (−0.73 MPa). Further, optimization studies indicated that all these 4 bacterial isolates produced EPS at 37 °C, 80 mM salt concentration and pH value 7.5 within 3 days of incubation. Further, among different carbon sources, sucrose followed by glucose was found to be best for production of EPS. Further work is going on to evaluate the efficacy of these potential EPS producing bacterial isolates under field conditions.

The anti-respiratory syncytial virus activity of methanol leaf extract of Aspilia africana

Respiratory syncytial virus (RSV), to date, is still the most frequent cause of infantile and childhood cause of viral lower respiratory tract illness on a global scale, and at the same time, causing significant impact in the elderly. Presently, there is no licensed vaccine or safe and specific antiviral agent that could be used against the virus. Medicinal plants are known to be a promising source for the discovery of utilizable anti-RSV treatments. In this present study, we screened the anti-RSV and cell cytotoxicity activities of methanol extract of A. Africana by virus plaque reduction and corresponding cell viability methods in Hep-2 and Vero cells of human and mammalian origin respectively. The corresponding set up for analyses of A. Africana extract on cell viability were performed by the reduction of thiazolyl blue tetrazolium bromide (MTT) in the Hep-2 cells following the established method. The results of an evaluation of the extract of A. africana showed anti-RSV activities with inhibition of RSV at IC50, 42.5 ± 8.89, while the cell cytotoxic effect in Hep2 cells recorded was TC50, 121.4. ± 7.21. Therefore, our results show that the methanol extract of AA exhibited anti-RSV activities and has a moderate effect on the cell viability of the recipient host cell, indicating that target molecular substances against RSV can be developed from the extract.

Application of heat-activated peroxydisulfate pre-oxidation for degrading contaminants and mitigating ultrafiltration membrane fouling in the natural surface water treatment

Membrane fouling is posing a critical obstacle limiting the widespread application of ultrafiltration (UF). Among the numerous membrane foulants, natural organic matter (NOM) is one of the most problematic since it exists ubiquitously in natural waters and can cause severe membrane fouling. This study investigated the removal of NOM in surface water and the mitigation of membrane fouling using heat-activated peroxydisulfate (PDS) as a pretreatment for UF process. The results demonstrated that the NOM was efficiently removed, with ultraviolet absorbance (UV254) and dissolved organic carbon (DOC) decreasing by approximately 71% and 52%, respectively, at a PDS dose of 0.8 mM within 60 min (80 °C). The chromatograms of high performance size exclusion chromatography (HPSEC) indicated that some high molecular weight humic substances with a peak at approximately 10 kDa were oxidized to low molecular weight organic matters distributed in the range of < 100 Da during the pretreatment process. Moreover, three-dimensional fluorescence parallel factor analysis (PARAFAC) indicated that humic-like substances were much more easily degraded by heat-activated PDS pretreatment than protein-like substances. These results indicated that some unsaturated NOM fractions were first degraded and then mineralized to carbon dioxide during pretreatment. Meanwhile, the destroyed structure of humic substances might hinder its binding with high valence cations to reduce the possibility of high valence cations deposited on the membrane surface, thereby reducing membrane fouling. Therefore, membrane fouling could be significantly mitigated due to the shifts of NOM concentration and structure by heat-activated PDS pretreatment in the surface water treatment.

Roles of molecular weight-fractionated extracellular polymeric substance in transformation of Au(III) to Au nanoparticles in aqueous environments

Extracellular polymeric substance (EPS) is widely distributed in natural environments and plays important roles in the biogeochemical cycling of heavy metal. Earlier works reported that EPS could reduce metal ions such as Au(III) and Ag(I) to corresponding metal nanoparticles (NPs). EPS is a complex mixture of microbiogenic polymers with wide molecular weight (MW) distribution, and the specific components of EPS responsible for Au(III) reduction and AuNPs stabilization are still not well understood. In this study, the EPS of Shewanella oneidensis MR-1 was divided into six fractions with MW of <3, 3–10, 10–30, 30–50, 50–100, and >100 kDa, respectively through the ultrafiltration method and the roles of MW-fractionated EPS in the reduction of Au(III) to AuNPs were investigated. It was found that the low MW (<3 kDa) EPS was the major reducing agent in EPS but the fraction itself could not convert high concentration (>25 mg/L) of Au(III) to stable AuNPs due to its inferior AuNPs-stabilizing capacity. The high MW (>50 kDa) EPS could act as coating reagents to increase the stability of the formed AuNPs with sizes of 20–50 nm, but had low Au(III)-reducing activity. The carboxyl-containing substances in EPS may play crucial roles in stabilizing AuNPs. This finding is important for a better understanding of the differential roles of MW-fractionated EPS in the transformation and fate of Au(III) and AuNPs, as well as other metal ions and metal NPs in natural environments.

Selective removal of color substances by carbon-based adsorbents in livestock wastewater effluents

Livestock wastewater effluent generated after the anaerobic treatment process contains the considerable amount of color-causing organic matter. In this study, a quantitative comparison of three carbon-based adsorbents included granular activated carbon (GAC), expanded graphite (EG), and multi-walled carbon nanotubes (MWNTs) was carried out for the potential application to the removal of color substances, and their mechanism was proposed. Although GAC showed the highest specific dissolved organic carbon (DOC) adsorption capacity, the color removal efficiency was the smallest among three adsorbents. The selective color removal ratios of EG and MWNTs reached 22.7 ± 0.1PtCo/mg-DOC-removed and 21.2 ± 0.1PtCo/mg-DOC-removed, respectively, while that of GAC was only 12.3 ± 0.1PtCo/mg-DOC-removed. The selective adsorption of color substances by graphene-based carbon materials was due to the aromatic π-π interaction between organic matter and the hexagonal carbon lattice of graphene. The analysis of molecular weight distribution also confirmed that the exposed surface area and macro-pores were responsible for the adsorption of high molecular weight color substances. The chemical regeneration of three adsorbents was examined using 1% NaOCl solution and MWNTs showed almost complete recovery of the initial color removal capacity. In conclusion, MWNTs were the most suitable carbon nanomaterial for the selective color removal from livestock wastewater effluent.

Вивчення спорідненості до мембран допоміжних речовин й фармакологічно активних інгредієнтів методами флуоресцентних і спінових зондів

Мета дослідження – порівняльне вивчення спорідненості до ліпосом з фосфатидилхоліну низки гідрофільних неводних розчинників пропіленгліколю (ПГ), поліетиленгліколей (ПЕГ) з молекулярною масою 400 і 1500 (ПЕГ­400 і ПЕГ­1500), що успішно застосовуються за створення м’яких лікарських форм як допоміжні речовини. Проведено аналіз результатів, отриманих за допомогою методу флуоресцентних зондів, і розрахунок константи дисоціації (Кд) неводних розчинників ПГ, ПЕГ­400 і ПЕГ­1500 з мембранами ліпосом з фосфатидилхоліну графічним методом у зворотних координатах. Показано, що Кд = 2,5 моль/л для ПГ і Кд = 4 • 10 ­1 моль/л для ПЕГ­400. Аналіз спектрів електронно­парамагнітного резонансу (ЕПР) у зворотних координатах дозволив оцінити Кд для ПЕГ­1500, що дорівнює 10­1 моль/л. Досліджено вплив ПГ і ПЕГ­400 на мембрани ліпосом. ПГ і ПЕГ­400 ефективно зв’язуються з мембраною ліпосом, витісняючи флуоресцентний зонд з мембрани в воду. Це може бути одним із механізмів впливу ПГ і ПЕГ­400 на біодоступність, коли фармакологічно активні інгредієнти (ФАІ) можуть витиснятися в воду молекулами допоміжних речовин, сповільнюючи процес всмоктування ФАІ. Введення ПЕГ­400 у суспензію ліпосом призводить до розпушення мембран, тобто, до зменшення щільності упаковки фосфоліпідів у мембранах, що може призводити до зміни їхньої проникності та підвищенню біодоступності. Дія ПГ на мембрани є більш м’якою, ніж ПЕГ­400. Вочевидь у зоні всмоктування ФАІ на мембрані паралельно відбувається процес всмоктування низькомолекулярних допоміжних речовин, наприклад, неводних розчинників. Причому всмоктування ліпофільних ФАІ може відбуватися в оточенні розчинників (допоміжних речовин), що призводить до збільшення біодоступності ФАІ. У разі конкуренції за місця зв’язування на мембранах клітин біоповерхонь між ФАІ і неводними розчинниками більш низька (на кілька порядків) спорідненість розчинників до мембран компенсується значною кількістю розчинників у м’якій лікарській формі порівняно з ФАІ. Механізмом підвищення біосумісності за допомогою ПЕГ є здатність їхніх молекул за рахунок компактизації (спіралізації) або розпушення приймати оптимальну конформацію структури, надаючи свої гідрофобні або полярні групи для оптимального зв’язування з наночастинками, лікарськими речовинами та біооб’єктами.

Changed PGA and POSTN levels in choroid plexus are associated with depressive-like behaviors in mice

Major depressive disorder (MDD) has become a potential cause of death and disability among young people worldwide. Numerous studies have indicated that the different cerebrospinal fluid (CSF) proteins may be used as mediums for MDD. Given the emergent interest of CSF proteins in MDD, we validated proteins expression in the choroid plexus (CP), the brain region that produces CSF in the lateral ventricle, the third ventricle, and the fourth ventricle of the central nervous system (CNS). The CSF constantly exchanges molecular substances with the brain tissue, which can dynamically reflect the metabolic microenvironment of the brain. In our previous study, Pepsin A (PGA) and periostin (POSTN) was associated with depressive-like behaviors of depressed macaca fascicularis models in CSF. Moreover, proteins that are expressed in the CP can be secreted into the CSF and may be associated MDD. This study sought to demonstrate the discrepancy of PGA and POSTN in the CP between Lipopolysaccharide (LPS)-induce depressed mice models and wild type (WT) mice. Our findings suggest that PGA and POSTN expression in CP of mice could be a possible candidate pathogenesis involved in MDD, which may contribute to a better understanding and treatment of MDD.

Crosstolerant Effect of Salt Priming and Viral Infection on Nicotiana Benthamiana

Currently, the salinization of soil one of the factors, which determine the productivity of crop plants. Under severe conditions, plants reveal the retardation in growth of shoots and roots,the decrease of productivity, because of biochemical and physiologicaleffects of salt high concentrations. To avoid any severe effect of biotic and abiotic stress is applied to the method of seed priming. Primed seed preserves the resistance signaling pathway for upcoming stress conditions. During biotic and biotic stress firstly accumulates reactive oxygen species which are the secondary messenger molecules in many signaling pathway of plant organisms. Excessive amounts of reactive oxygen species lead to macromolecules damage, such as lipids of cell walls, proteins, nucleic acids. To overcome the severe effect, plants evolved enzymatic and non-enzymatic systems of protection. The crucial enzymes are catalase, aldehyde oxidase, superoxide dismutase. The main components of the non-enzymatic antioxidant system are vitamins, low molecular mass substances such as glutathione. The phenomenon “cross-tolerance” suggests the resistance of plant organism to one stress by the exposure to another one. Early exposure salt stress to Nicotiana benthamiana leads to resistance to viral infection, change the activity of antioxidant enzymes (catalase, aldehyde oxidase). The analysis of viral particles revealed the decrease of viral particles content in salt primed plants.

Effect of Different Passivating Agents on the Stabilization of Heavy Metals in Chicken Manure Compost and Its Maturity Evaluating Indexes

We explore the effects of different passivating agents on livestock manure treatment by using chicken manure and straw as raw materials and thermophilic rapid fermentation. We investigate the effects of sepiolite (SE), calcium magnesium phosphate fertilizer (NP), biochar (BI), compounds of sepiolite plus calcium magnesium phosphate fertilizer (S+N), sepiolite plus biochar (S+B), calcium magnesium phosphate fertilizer plus biochar (N+B), and sepiolite plus calcium magnesium phosphate fertilizer and biochar (SNB) on the physical and chemical characteristics, heavy metal fraction and distribution, and organic matter content in chicken manure compost. The results showed that the addition of different passivating agents significantly increased the pH in chicken manure organic fertilizer (P<0.05). The seed germination rate was increased after applying of passivation agents, being>80%, and the germination inhibition rate decreased accordingly, whereas the values of electric conductivity (EC) and organic carbon were inhibited. The total nitrogen content and carbon/nitrogen ratio (C/N) were lower than of those before composting, and all of the indicators reached the standard of organic fertilizer maturity. However, differences among the groups after composting were that the pH increase in the compounding treatment was comparatively higher, and that the EC decreased significantly under the treatment of the single sepiolite and calcium magnesium phosphate, whereas the total nitrogen content and C/N ratio of organic carbon were not significantly different in each group. Although the total amount of heavy metals in our organic chicken manure fertilizer increased due to a concentration effect, the proportion of exchangeable heavy metals in the fertilizer decreased, and while the ratio of the residual heavy metals increased. The passivation effect on heavy metals under combined treatments of different materials was better than that of a single agent, and the SNB treatment had the best effect on the passivation of Ni, Zn, As, and Pb. After composting treatment, the concentrations of humic substances (HS) and humic acid (HA) increased significantly (P<0.05), and the highest concentrations increased by 19.8% and 78.9%, respectively. The amount of fulvic acid (FA) decreased by 4.47%-20.11% compared with the initial conditions. Infrared spectroscopy analysis showed that the small molecular substances of polysaccharides increased after composting. In summary, the addition of a passivation agent can promote the heavy metal passivation in chicken manure organic fertilizers to potentially render the compost as harmless.

Characterizing Soil Dissolved Organic Matter in Typical Soils from China Using Fluorescence EEM–PARAFAC and UV–Visible Absorption

Dissolved organic matter (DOM) strongly participates in a variety of critical environmental and ecological processes and has a large impact on environmental quality. In this study, ultraviolet–visible absorbance spectroscopy and excitation–emission matrices of fluorescence spectroscopy in combination with parallel factor analysis (EEMs–PARAFAC) were applied to characterize a total of 92 DOM samples extracted from four typical soil types under three different land-use regimes across China. DOC concentrations ranged from 6.52 ± 1.09 to 25.62 ± 4.83 mg L−1 and were generally higher in red soil from Guangdong and Guangxi, especially in paddy soil. Three fluorescence components were identified in soil DOM by EEMs–PARAFAC, including high molecular weight UVA humic-like substances (C1), low molecular weight autochthonous humic-like substances (C2), and protein-like substances (C3). DOM from black soil in Heilongjiang, purple soil from Sichuan, and red soil from Zhejiang had more humic-like substances, whereas DOM from yellow soil in Guizhou and red soil from Guangdong and Guangxi had lower degree of aromaticity and higher proportion of microbial-derived protein-like components (C3). Moreover, DOM from paddy soil tended to be more of protein-like components (C3) than that from other land uses and DOM from dryland soil generally had more autochthonous humic-like substances (C2). Our results demonstrated that soil DOM characteristics both varied significantly by soil type and land use, and EEMs–PARAFAC could be a useful approach to characterize the components and sources of heterogeneous DOM in soils.

Soil organic carbon storage and quality are impacted by corn cob biochar application on a tropical sandy loam

Humic substances, which are integral components of total organic carbon (TOC), influence soil quality. The study aimed to investigate whether humic and non-humic fractions exhibit early, consistent, and measurable changes and affect TOC sensitivity and storage in a tropical sandy loam soils amended with corn cob biochar. There were four treatments with four replicates established in a randomized complete block design. Composite soil samples were taken from plots without biochar (CT), from plots incorporated with 15 t biochar ha−1 (BC-15), and 30 t biochar ha−1 without or with phosphate fertilizer (BC-30 and BC-30+P). The TOC, and humin, humic acid (HA), and fulvic acid (HA) fractions of soil organic carbon were determined for each treatment. The optical densities (400–700 nm) were measured on the soil-free extracts by spectrophotometry; the densities measured at 465 and 665 nm were used to calculate the E465/E665 ratios. The BC-30 and BC-30+P plots recorded the highest TOC, humin, humic acid (HA), and fulvic acid (FA) contents with respect to the lowest in the CT. The total exchangeable carbon stratification was significantly higher in all the biochar-treated plots relative to the CT. Spectral analysis showed higher values of E465/E665 (5.02 and 5.15) in the CT and BC-15-treated soils, respectively, compared with the BC-30 and BC-30+P-amended soils with E465/E665 ratios of 2.76 and 2.98, respectively. Corn cob biochar applied to a tropical sandy loam: • increased the concentrations of HA and FA and led to increased stratification of TOC, with a stronger effect on HA compared with FA; • significantly lowered E465/E665 at the high biochar application rate of 30 t ha−1, implying the dominance of high molecular weight humic acid-like substances, and increased degree of aromaticity of the TOC.

Природа хлорорганических соединений в нефти и нефтяных фракциях

In this review, published information on the nature and molecular compositions of organochlorine compounds (OCCs), which are found in crude oil and in its refined products, is systematized. The native and added OCCs are reviewed. The formers are concentrated predominantly in high molecular weight resinous-asphaltene substances of crude oil, the latter’s, referred to as light organochlorine compounds, are present in the gasoline fractions. The following chemicals that are used for oil production are regarded as possible sources of OCCs: inhibited hydrochloric acid, acid compounds; organic solvents of asphalt-resin-paraffin deposits, organic solvents served for oil production stimulation, and possible products of a mutual solvent chlorination with hydrochloric acid.

Sulfurimonas crateris sp. nov., a facultative anaerobic sulfur-oxidizing chemolithoautotrophic bacterium isolated from a terrestrial mud volcano.

A novel mesophilic facultative anaerobic bacterium, strain SN118T, was isolated from a terrestrial mud volcano in Taman Peninsula, Russia. The cells were Gram-negative, motile, short, straight or curved rods with a single polar flagellum. Growth was observed at 5-40 °C (optimum, 30 °C) and pH 5.5-9.5 (optimum, pH 8.0). Growth of strain SN118T was observed in NaCl concentrations ranging from 0.5 to 8.0 % (w/v) with an optimum at 2.0-3.0 % (w/v). The isolate grew chemolithoautotrophically with sulfide, elemental sulfur or thiosulfate as electron donor, oxygen, nitrate or nitrite as an electron acceptor and CO2/HCO3 - as a carbon source. Molecular hydrogen or organic substances did not support growth. Nitrate was reduced to N2. The dominant fatty acids were C16 : 1ω7c, C16 : 0 and C18 : 1ω7c. The total size of the genome of the novel isolate was 2 209 279 bp and the genomic DNA G+C content was 38.8 mol%. Results of phylogenetic analysis based on 16S rRNA gene sequences indicated that the novel isolate belonged to the genus Sulfurimonas and was most closely related to Sulfurimonas denitrificans DSM 1251T (96.74 %). Based on its physiological properties and results from phylogenetic analyses, including average nucleotide identity and in silico DNA-DNA hybridization values, the isolate is considered to represent a novel species of the genus Sulfurimonas, for which the name Sulfurimonas crateris sp. nov. is proposed. The type strain is SN118T (=DSM 109248T=VKM B-3378T).

Effects of electrical-hydrothermal aging degradation on dielectric and trap properties of high temperature vulcanized silicone rubber materials.

In this paper, a new aging platform combined the high voltage electric field and the hydrothermal environment was built. To investigate the aging mechanism, physicochemical, dielectric and trap properties of HTV SR before and after electrical-hydrothermal aging for 24 days were discussed. The results indicated that, compared with hydrothermal aging, more cracks and holes appeared on the surface of HTV SR after electrical-hydrothermal aging, and the content of flame retardant decreased significantly. Due to the main chain and side chain scission of PDMS, lots of low weight molecular (LWM) substances and free radicals were produced. And the tensile strength and elongation at break significantly decreased. Various physical and chemical defects appeared in the HTV SR specimen in the process of electrical-hydrothermal degradation, as a result of which, the dielectric constant significantly increased and the peak trap density increased by about 2.5 times compared to the virgin sample. The increase in trap density in turn accelerated the charge accumulation and enhanced the breakdown probability, resulting in the electric field strength decrease from 21.8 kV mm−1 to 16.1 kV mm−1 and severe degradation of HTV SR.