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关键词： Arsenic toxicity   P. indica   Artemisia annua   Transcripts   Flavonoids   Artemisinin  

摘要： Aim of the current study was to investigate the effect of exogenously inoculated root endophytic fungus, Piriformospora indica, on molecular, biochemical, morphological and physiological parameters of Artemisia annua L. treated with different concentrations (0, 50, 100 and 150 mu mol/L) of arsenic (As) stress. As was significantly accumulated in the roots than shoots of P. indica-inoculated plants. As accumulation and immobilization in the roots is directly associated with the successful fungal colonization that restricts most of As as compared to the aerial parts. A total of 4.1, 11.2 and 25.6 mg/kg dry weight of As was accumulated in the roots of inoculated plants supplemented with 50, 100 and 150 mu mol/L of As, respectively as shown by atomic absorption spectroscopy. P. indica showed significant tolerance in vitro to As toxicity even at high concentration. Furthermore, flavonoids, artemisinin and overall biomass were significantly increased in inoculated-stressed plants. Superoxide dismutase and peroxidase activities were increased 1.6 and 1.2 fold, respectively under 150 mu mol/L stress in P. indica-colonized plants. Similar trend was followed by ascorbate peroxidase, catalase and glutathione reductase. Like that, phenolic acid and phenolic compounds showed a significant increase in colonized plants as compared to their respective control/un-colonize stressed plants. The real-time PCR revealed that transcriptional levels of artemisinin biosynthesis genes, isoprenoids, terpenes, flavonoids biosynthetic pathway genes and signal molecules were prominently enhanced in inoculated stressed plants than un-inoculated stressed plants.

关键词： Hyaluronate lyase   Thermophilic   Exolytic  

摘要： Hyaluronic acid (HA) is an anionic linear polysaccharide abundantly distributed in the extracellular matrix of mammalian connective, growing, and tumor tissues. Hyaluronidase is used as an important drug diffusion promoter and a tool enzyme to produce HA oligosaccharides. However, there is no thermostable hyaluronidase suitable for application to date. In this study, a thermophilic hyaluronate lyase, TcHly8C, from Thermasporomyces composti DSM22891 was expressed in Escherichia coli. The recombinant TcHly8C was most active at 70 degrees C, and it retained about 30% of initial activity after incubation at 60 degrees C for 28 days. The half-lives of TcHly8C at 60 degrees C and 70 degrees C were 16.1 d and 2.3 h, respectively. The optimum pH of TcHly8C is 5.93, and it was stable at pH 6.15-10.90. The presence of Mg2+ could enhance its enzymatic activity significantly. Km, kcat, and kcat/Km of TcHly8C towards HA were 3.69 ***(-1), 17.82 s(-1), and 4.82 ***(-1).s(-1), respectively. TcHly8C degraded HA in an exolytic mode, and the end product was unsaturated HA disaccharide (.UA-GlcNAc). Overall, our results showthat TcHly8C is the first reported PL8 exo-type hyaluronate lyase with high thermostability, which provides a potential enzyme used in medicine and production of HA oligosaccharides. (C) 2020 Elsevier B.V. All rights reserved.

关键词： ClpB   Chaperones   Hsp100   M. tuberculosis  

摘要： Tuberculosis, caused by pathogenic M. tuberculosis, remains a global health concern among various infectious diseases. Studies show that ClpB, amajor disaggregase, protects the pathogen from various stresses encountered in the host environment. In the present study we have performed a detailed biophysical characterization of M. tuberculosis ClpB followed by a high throughput screening to identify small molecule inhibitors. The sedimentation velocity studies reveal that ClpB oligomerization varies with its concentration and presence of nucleotides. Further, using high throughput malachite green-based screening assay, we identified potential novel inhibitors of ClpB ATPase activity. The enzyme kinetics revealed that the lead molecule inhibits ClpB activity in a competitive manner. These drugs were also able to inhibit ATPase activity associated with E. coli ClpB and yeast Hsp104. The identified drugs inhibited the growth of intracellular bacteria in macrophages. Small angle X-ray scattering based modeling shows that ATP, and not its non-hydrolyzable analogs induce large scale conformational rearrangements in ClpB. Remarkably, the identified small molecules inhibited these ATP inducible conformational changes, suggesting that nucleotide induced shape changes are crucial for ClpB activity. The study broadens our understanding of M. tuberculosis chaperone machinery and provides the basis for designing more potent inhibitors against ClpB chaperone. (C) 2020 Elsevier B.V. All rights reserved.

关键词： Pretreatment   Wood   Fibers   Biofuels   Pyrolysis  

摘要： Pretreatments of lignocellulosic biomass prior to fast pyrolysis need to give a better yield and quality of pyrolysis oil and be practical to implement at a commercial scale. This study demonstrated, at a large pilot scale, that thermomechanical refining can reduce the particle size, hemicellulose content, and mineral content of pine wood chips, leading to improved yields of carbohydrate-derived chemicals on fast pyrolysis. Additionally, a hemicellulose-rich byproduct can be generated during the pretreatment for separate valorization. The impact of different presteaming times, citric acid infusion, and disc refining on the yield and composition of the pyrolysis oil was studied. Presteaming of citric acid-infused wood chips at 173 degrees C for 3 min and refining to wood fiber proved most effective in improving the yield of pyrolysis oil organics, including the valuable biochemicals levoglucosan and hydroxyacetaldehyde, while reducing the yields of low-value char and noncondensable gases.

关键词： Predictive markers   Prostate cancer   Risk factors  

摘要： Background Although prostate cancer is a leading cause of cancer death, its aetiology is not well understood. We aimed to identify novel biochemical factors for prostate cancer incidence and mortality in UK Biobank. Methods A range of cardiovascular, bone, joint, diabetes, renal and liver-related biomarkers were measured in baseline blood samples collected from up to 211,754 men at recruitment and in a subsample 5 years later. Participants were followed-up via linkage to health administrative datasets to identify prostate cancer cases. Hazard ratios (HRs) and 95% confidence intervals were calculated using multivariable-adjusted Cox regression corrected for regression dilution bias. Multiple testing was accounted for by using a false discovery rate controlling procedure. Results After an average follow-up of 6.9 years, 5763 prostate cancer cases and 331 prostate cancer deaths were ascertained. Prostate cancer incidence was positively associated with circulating vitamin D, urea and phosphate concentrations and inversely associated with glucose, total protein and aspartate aminotransferase. Phosphate and cystatin-C were the only biomarkers positively and inversely, respectively, associated with risk in analyses excluding the first 4 years of follow-up. There was little evidence of associations with prostate cancer death. Conclusion We found novel associations of several biomarkers with prostate cancer incidence. Future research will examine associations by tumour characteristics.

关键词： Anatomy   Thermoresponsive polymers   Thermal properties   Wound healing   Hydrogels  

摘要： A two-pronged strategy of biomechanically active and biochemically functional hydrogel wound dressing which can assist wound closure and have multiple functions to promote wound healing has been rarely reported. Herein, we designed a series of biomechanically active injectable self-healing hydrogels based on quaternized chitosan (QCS), polydopamine-coated reduction graphene oxide (rGO-PDA), and poly(N-isopropylacrylamide) (PNIPAm) as multifunctional wound dressings to promote wound closure and wound healing. These biomechanically active wound dressings have excellent thermoresponsive self-contraction and tissue adhesion properties. They adhere strongly to the skin and assist wound closure by actively contracting wounds through self-contraction. Moreover, these hydrogels exhibit biochemical multifunctions that are beneficial to wound healing, including good self-healing property, temperature-dependent drug release ability, anti-infection, antioxidation, and conductivity. The in vivo full-thickness skin defect model demonstrates that the hydrogel dressings significantly promoted wound closure with accelerated wound contraction and promoted the wound-healing process with higher granulation tissue thickness, collagen disposition, and enhanced vascularization. In summary, the biomechanically active injectable self-healing conductive adhesive hydrogels promoted wound healing by assisting wound closure and biochemical functions, opening a two-pronged strategy approach to wound management through combining biomechanical and biochemical functions together.

关键词： artificial cells   membrane   reaction-diffusion   self-organization   synthetic biology  

摘要： The MinDE proteins from E. coli have received great attention as a paradigmatic biological pattern-forming system. Recently, it has surfaced that these proteins do not only generate oscillating concentration gradients driven by ATP hydrolysis, but that they can reversibly deform giant vesicles. In order to explore the potential of Min proteins to actually perform mechanical work, we introduce a new model membrane system, flat vesicle stacks on top of a supported lipid bilayer. MinDE oscillations can repeatedly deform these flat vesicles into tubules and promote progressive membrane spreading through membrane adhesion. Dependent on membrane and buffer compositions, Min oscillations further induce robust bud formation. Altogether, we demonstrate that under specific conditions, MinDE self-organization can result in work performed on biomimetic systems and achieve a straightforward mechanochemical coupling between the MinDE biochemical reaction cycle and membrane transformation.

关键词： RNA recycling   RNase J paralogs   metalloribonucleases   metal cofactors   RNA degradosome   exoribonuclease II (Rnase II)   metalloenzyme   oligomerization   protein-protein interaction   metal ion–   protein interaction   metal cofactors  

摘要： RNase J enzymes are metallohydrolases that are involved in RNA maturation and RNA recycling, govern gene expression in bacteria, and catalyze both exonuclease and endonuclease activity. The catalytic activity of RNase J is regulated by multiple mechanisms which include oligomerization, conformational changes to aid substrate recognition, and the metal cofactor at the active site. However, little is known of how RNase J paralogs differ in expression and activity. Here we describe structural and biochemical features of two Staphylococcus epidermidis RNase J paralogs, RNase J1 and RNase J2. RNase J1 is a homodimer with exonuclease activity aided by two metal cofactors at the active site. RNase J2, on the other hand, has endonuclease activity and one metal ion at the active site and is predominantly a monomer. We note that the expression levels of these enzymes vary across Staphylococcal strains. Together, these observations suggest that multiple interacting RNase J paralogs could provide a strategy for functional improvisation utilizing differences in intracellular concentration, quaternary structure, and distinct active site architecture despite overall structural similarity.

关键词： hypoxia/oxygen sensor   prolyl-hydroxylase   hypoxia-inducible factor (HIF)   2-oxoglutarate/α-ketoglutarate oxygenase   Dictyostelium discoideum   Toxoplasma gondii   S-phase kinase-associated protein 1 (Skp1)   hypoxia   dioxygenase   protein evolution  

摘要： In animals, the response to chronic hypoxia is mediated by prolyl hydroxylases (PHDs) that regulate the levels of hypoxia-inducible transcription factor alpha (HIF alpha). PHD homologues exist in other types of eukaryotes and prokaryotes where they act on non HIF substrates. To gain insight into the factors underlying different PHD substrates and properties, we carried out biochemical and biophysical studies on PHD homologues from the cellular slime mold, Dictyostelium discoideum, and the protozoan parasite, Toxoplasma gondii, both lacking HIF. The respective prolyl-hydroxylases (DdPhyA and TgPhyA) catalyze prolyl-hydroxylation of S-phase kinase-associated protein 1 (Skp1), a reaction enabling adaptation to different dioxygen availability. Assays with full-length Skp1 substrates reveal substantial differences in the kinetic properties of DdPhyA and TgPhyA, both with respect to each other and compared with human PHD2;consistent with cellular studies, TgPhyA is more active at low dioxygen concentrations than DdPhyA. TgSkp1 is a DdPhyA substrate and DdSkp1 is a TgPhyA substrate. No cross-reactivity was detected between DdPhyA/TgPhyA substrates and human PHD2. The human Skp1 E147P variant is a DdPhyA and TgPhyA substrate, suggesting some retention of ancestral interactions. Crystallographic analysis of DdPhyA enables comparisons with homologues from humans, Trichoplax adhaerens, and prokaryotes, informing on differences in mobile elements involved in substrate binding and catalysis. In DdPhyA, two mobile loops that enclose substrates in the PHDs are conserved, but the C-terminal helix of the PHDs is strikingly absent. The combined results support the proposal that PHD homologues have evolved kinetic and structural features suited to their specific sensing roles.

关键词： micro dielectric barrier discharge plasma   Panax ginsengC   A   Meyer   growth rate   chlorophyll   total phenolic content   radical scavenging activity  

摘要： We confirmed that micro dielectric barrier discharge plasma improved the growth and immunity ofPanax ginsengC. A. Meyer seedlings. The growth rate of the ginseng seedlings was compared by height and weight monitoring. The length and weight of the aerial part of the 3 min. Plasma treated ginseng increased by 25% and 54%, respectively, compared to the untreated ginseng. The difference between the initial root weight before planting in the soil and the root weight 5 weeks after planting in the soil increased by 28% and 22% for the 3 and 10 min. Plasma treated ginseng, respectively. Chlorophyll and total phenolic contents were increased 62% and 56%, respectively in the aerial part of the plasma-treated ginseng seedlings compared to the untreated controls. Radical scavenging activity was also increased by 18% in the 3 min plasma treated ginseng seedlings. The plasma treatment increased the expression level of chlorophyll metabolism-related and auxin response factor genes in ginseng and might be the result of ginseng growth development by enhancing plant growth hormone. Increasing disease resistance through induced systemic resistance can ultimately improve crop productivity by strengthening the immune system. We demonstrated this by comparing the transcription patterns of genes involved in the pathogenic defense mechanisms of ginseng. The expression of the pathogen-associatedPgPR2, PgPR5, PgPR10andPgCATgenes improved significantly and rapidly in the plasma treated ginseng seedlings. In particular, mRNA expression levels of thePgPR2andPgPR5genes were significantly increased 5- and 3-fold, respectively, in the 10 min plasma treated seedlings. An increased expression level of abscisic acid signaling related genes (PgABFandPgPYL) means an increased resistance to stress, which in turn, could affect the enhanced antioxidant activity. Our results suggest that plasma can enhance the growth and increase the immunity of ginseng seedlings especially by improving its resistance to p