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Glutathione-S-transferases (GSTs) are multifunctional phase II detoxification enzymes that catalyze the attachment of electrophilic substrates to glutathione, and play an important role in protecting organisms against the toxicity of reactive oxygen species. In this study, two distinct sigma-class GST (CpGSTσ1 and 2) cDNA sequences were cloned from freshwater bivalve Cristaria plicata . The full length cDNA of CpGSTσ1 and 2 was 826 bp and 1609 bp, which encoded 213 and 248 amino acid residues, respectively. Their transcripts were expressed in all detected tissues and the highest expression level was in hepatopancreas from C. plicata . The expression level of CpGSTσ1 and 2 in hepatopancreas and hemocytes showed a significantly increased trend after bacterial challenge. The recombinant CpGSTσ1 was successfully expressed as a soluble form in Escherichia coli DE3. The specific activity of recombinase toward CDNB was 46.965 ± 0.082 μmol/min/mg, and its optimum temperature and pH was 37 °C and 9.0, respectively. The recombinant of CpGSTσ1 could bear 6 M urea and 8% SDS, when the concentration of urea was 8 M and its activity was only below 20%. The results might provide a better perspective on the mechanisms of resistance to bacterial infection in molluscs. [ABSTRACT FROM AUTHOR]

Abstract: Rehmannia glutinosa, a widely used Chinese medicinal herb, has been shown to suffer from serious consecutive monoculture problems that cause significant decline in both yield and quality. The objective of this study was to evaluate the response of the soil microbial community and the effect on catabolic diversity to consecutive monoculture regime using three different techniques: substrate-induced respiration (SIR), phospholipid fatty acid (PLFA) and community-level physiological profiles (CLPP) analyses. We found that basal soil respiration (BSR) was significantly higher in the control and newly planted soils than in the second and third year consecutive monoculture soils. However, no significant difference was observed in SIR among the newly planted, second and third year consecutive monoculture soils. The PLFA signatures indicated that the bacterial biomass was larger than the fungal biomass in all four treatments and both enhanced with the increasing years of monoculture and attained the peak in SM. The ratio of cyclopropyl PLFAs to their metabolic precursors (cy/pre), a measure of physiological stress in microbial communities, in the second and third year consecutive monoculture soils was significantly greater than that in the control and newly planted soils. Biolog analysis results revealed that the consumption of carboxylic acids, phenolic acids and amines, especially acid carbon substrates, in the consecutively monocultured soil was significantly greater than that in the newly planted soil. Both PLFA- and CLPP-based principal component analysis (PCA) and cluster analysis revealed the distinct separation between the control, newly planted plots and the second, third year consecutive monoculture plots. Through our PLFA-based and Biolog analysis, together with microbial respiration determination, we were able to reveal characteristic differences in the microbial community composition and activities in the rhizosphere following R. glutinosa monoculture. [Copyright &y& Elsevier]

Potassium chloride crystals are cubic, which often leads to caking and greatly limits their applications. This caking can be overcome by modifying the crystal shape toward sphericity. Spherical particles have a high anti-caking ability and flowability. In this work, spherical KCl particles were prepared using a simple cooling crystallization process designed to function without additives. Among the four main processes in the crystallization of spherical particles, i.e., nucleation, growth, agglomeration, and attrition, agglomeration is the greatest contributor to the formation of spherical KCl particles, which were prepared following the principle that the adhesion force must be larger than the dispersion force. The adhesion free energy between KCl particles and solvents (i.e., water, n -hexane, formamide, diazomethane, methanol, ethanol, ethyl acetate, ethylene glycol, and dimethyl sulfoxide) was calculated using the Lifshitz–van der Waals acid–base approach, and water was found to be the most appropriate solvent because of its attractive interaction with the crystals. According to the relationship between the adhesion force and dispersion forces, we found that the stirring rate should be lower than 1300 rpm. Additionally, the effects of stirring rate and cooling rate on the KCl products were investigated and optimized, and the optimal conditions were found to be 400–500 rpm and 10–15 min/ ° C, respectively. All of the spherical KCl products prepared under the optimal conditions show a better morphology, flowability, and anti-caking performance than the original crystals. [ABSTRACT FROM AUTHOR]

Catalytic ammonia decomposition is an attractive method to generate hydrogen at mid-temperatures (<700 °C) but must incorporate precious metals (Pd, Ru, etc.) to ensure high reactivity. Developing Ni-based catalysts to decompose ammonia can enhance its prospect for hydrogen generation. However, the catalytic activity of Ni is hardly satisfactory at mid-temperatures. In this work, we show the bimetallic Ni x Co 10-x /CeO 2 towards mid-temperature NH 3 decomposition, with the metal loading of Ni and Co tuned. Kinetics study demonstrates that the NH 3 decomposition reaction follows the Temkin Pyzhev mechanism and the synergy between Ni and Co can decrease the reaction orders regarding NH 3 and increase the reaction orders regarding H 2. Mechanistic results indicate that the recombinative N desorption limits the reaction rate. The synergy between Ni and Co can simultaneously decrease the energy barriers of the recombinative N desorption and mitigate the H 2 poisoning effect. Therefore, Ni 7.5 Co 2.5 /CeO 2 displays both high ammonia conversion (96.96%) and hydrogen formation rate (1947.9 mmol/(g cat.h)) at 650 °C. We hope the mechanism in this work can be used to guide the design of inexpensive catalysts to decompose ammonia at mid-temperatures. [Display omitted] • NH 3 decomposition over Ni x Co 10-x /CeO 2 follows the Temkin Pyzhev mechanism. • The recombinative desorption of N is the rate-limiting step. • The generated H 2 can poison the active sites on the surface. • The synergy between Ni and Co can decrease the energy barriers of the rate-limiting step and mitigate the H 2 poisoning. • Ni 7.5 Co 2.5 /CeO 2 is an effective catalyst towards mid-temperature NH 3 decomposition. [ABSTRACT FROM AUTHOR]

Fe 2 O 3 is prospective for the chemical looping redox cycles but must contain a significant amount of inert supports to ensure high stability. The traditional inert supports (Al 2 O 3 , MgAl 2 O 4 , etc.) have a dilution effect on Fe 2 O 3 , which results in a compromised reactivity. In this work, we propose several Sr, Mg co-doped LaGaO 3-δ to support Fe 2 O 3 for chemical looping water splitting and investigated the synergy for the enhanced performance. Mechanistic study manifests that doping Sr increases the amount of oxygen vacancies, promoting the oxygen release and uptake during the redox reaction. Doping Mg mitigated the interaction between Fe 2 O 3 and the supports, leading to much enhanced stability. Therefore, Fe 2 O 3 /La 0.6 Sr 0.4 Mg 0.4 Ga 0.6 O 3-δ shows both high hydrogen yield (9.75 mmol.g−1) and peak hydrogen production rate (3.7 mmol.g−1.min−1). The performance shows only a slight decrease even after 100 cycles. The observed results can also inspire the selection and development of advanced supports to improve both the reactivity and stability of oxygen carriers. [Display omitted] • Sr improves oxygen vacancy concentration of the oxygen carriers. • High oxygen vacancy concentration improves the oxygen release/uptake rate. • Mg mitigates the reaction between iron and support to ensure reversible phase change. • Fe 2 O 3 /La 0.6 Sr 0.4 Mg 0.4 Ga 0.6 O 3-δ is highly active and stable for chemical looping reaction. [ABSTRACT FROM AUTHOR]

The rapid accumulation of lignin in the cell wall is one of important immune defense mechanism in response to adversity stress in plants. In this study, we found that the enlargement of the root tubers of Rehmannia glutinosa (R. glutinosa) is arrested under consecutive monoculture stress, and this process is accompanied by abnormal accumulation of lignin. Meanwhile, the function of key catalytic enzyme genes in lignin biosynthetic pathway under consecutive monoculture stress was systematically analyzed, of which roles of core genes were validated using reverse genetics. We elucidated that an abnormal deposition of lignin in R. glutinosa roots, induced by consecutive monoculture stress, and arrested the enlargement of root tubers. Additionally, by manipulating the key catalytic enzyme gene RgCCR6 , we were able to alter lignin content of roots of R. glutinosa , thereby affecting tuber enlargement. We speculate that cell lignification is an important defense strategy in resistance against consecutive monoculture stress, but the overreacted defense hindered the normal enlargement of root tubers. The findings provide new insights for effectively improving yield reductions of root crops subjected to environmental stress. • Consecutive monoculture stress induced special deposition of lignin in the cambium cells. • Over-immunity led to abnormal deposition of lignin in cambium cells. • Abnormal deposition of lignin limited root tubers enlargement. • RgCCR in lignin biosynthesis was core node affected root tubers enlargement. [ABSTRACT FROM AUTHOR]