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关键词： Biochemistry  

摘要： The worldwide dependence of population on fossil fuels continues to have several harmful implications for the environment. Bioethanol is an excellent option for renewable fuel to replace the current greenhouse gas emitters. In addition, its production by enzymatic route has gained space among the industrial processes because it replaces the traditional acid treatment. Due to its high versatility, the xylanase family is used in this process as an accessory enzyme for degrading the lignocellulosic substrate of biomass. A chimera built by a xylanolytic domain (Xyl) and a xylose-binding protein (XBP) showed an experimentally improved catalytic efficiency and interdomain allosteric modulation after xylose binding. In this context, we performed a quantum biochemistry characterization of the interactions between these domains and dynamic cross-correlation (DCC) analysis after performing molecular dynamics (DM) simulations of the systems in the presence and absence of xylose in the XBP active site. We used the density functional theory (DFT) within the molecular fractionation with the conjugated caps (MFCC) approach to describe the pair energies, and the corresponding energy difference between the chimera domains responsible for the allosteric effect and amino acid DCC to evaluate the interdomain coupling differences between the energy states. The detailed energetic investigation together with the related structural and dynamics counterparts revealed the molecular mechanisms of chimeric improvement of the xylanase activity observed experimentally. This mechanism was correlated with greater stability and high connectivity at the interdomain interface in the xylose bound relative to the free chimera. We identify the contributions of hydrogen bonds, hydrophobic interactions and water-mediated interactions in the interdomain region responsible for stability together with the structural and dynamical elements related to the allosteric effect. Taken together, these observations l

关键词： functional food   thermal treatment   plant metabolome   phytochemicals   organosulfur   glycerophospholipids   Maillard reaction  

摘要： Aged black garlic (BG) is a functional food in global markets;however, very few studies have ventured into comprehensive profiling of BG metabolomes during the aging process. Herein, we exploited UHPLC-Orbitrap HRMS for a comparative metabolomics analysis. During the heat treatment, organosulfur compounds such as allicin, diallyl disulfide, ajoene, S-allyl-L-cysteine (SAC), and gamma-glutamyl-SAC were downregulated. Plenty of glycerophospholipids together with shikimate, aromatic amino acids, and vitamin B6 vitamers were significantly augmented;tryptophan was however consumed to generate downstream products manifested in nicotinate metabolism and aminobenzoate degradation. These secondary metabolites serve as signaling mediators or protectants against extreme thermal exposure. Besides, Heyns compounds and Amadori-rearrangement byproducts with potential mutagenic effects were concentrated. Together, our findings expand the known metabolome space of BG processing and better elucidate the reactivities of the key metabolites. We provide in-depth insights into the biochemical changes of BG that enable further functional or toxicological investigations of this popular food.

关键词： Fish   Wetland   Pesticides   Metabolism  

摘要： World food production is directly related to human population growth. Chemicals are constantly applied to pest control in crops to increase productivity. Therefore, sustainable alternatives are needed to reduce environmental impacts. The biochemical responses in liver and muscle of Astyanax lacustris collected in different rice planting systems were analysed. Ten fish were collected in organic rice cultivation systems and conventional as well as water and sediment for pesticide analysis. In water from conventional system, bentazon (56.1 mu g L-1), fipronil (0.226 mu g L-1) and propoxur (0.141 mu g L-1) were found, while azoxystrobin and quinclorac were below the limit of quantification (LOQ). There were no pesticides in the sediment from the conventional system. In the water of the organic system, only propoxur (below the LOQ) was registered. Metalaxil (0.025 mu g kg(-1)) were verified in the sediment, while diphenoconazole, dinoxifene and tebuconazole were below the LOQ. The presence of these pesticides in crops with an organic production system may be related to proximity to crops to conventional production systems. Besides this, the amount is very low as compared with conventional system. Muscle glycogen, protein and amino acid levels were higher in fish collected in organic ponds. Lactate and ammonia levels were higher in conventional cultures. Lipids and proteins had greater oxidative damage in both tissues in the conventional system. Although pesticides were detected in organic sediments, the parameters of metabolic and oxidative damage were probably related by exposure to higher concentrations of pesticide in the water or by the lower oxygen content of conventional systems. However, fish mortality was not observed during collections. Despite being an anthropic environment, areas of organic cultivation seem to present better conditions for the survival of A. lacusiris. (C) 2020 Elsevier B.V. All rights reserved.

关键词： phosphoinositide homeostasis   lipid kinase   lipid phosphatase  

摘要： The phosphoinositide PI(3,5)P-2, generated exclusively by the PIKfyve lipid kinase complex, is key for lysosomal biology. Here, we explore how PI(3,5)P-2 levels within cells are regulated. We find the PIKfyve complex comprises five copies of the scaffolding protein Vac14 and one copy each of the lipid kinase PIKfyve, generating PI(3,5)P-2 from PI3P and the lipid phosphatase Fig4, reversing the reaction. Fig4 is active as a lipid phosphatase in the ternary complex, whereas PIKfyve within the complex cannot access membrane-incorporated phosphoinositides due to steric constraints. We find further that the phosphoinositide-directed activities of both PIKfyve and Fig4 are regulated by protein-directed activities within the complex. PIKfyve autophosphorylation represses its lipid kinase activity and stimulates Fig4 lipid phosphatase activity. Further, Fig4 is also a protein phosphatase acting on PIKfyve to stimulate its lipid kinase activity, explaining why catalytically active Fig4 is required for maximal PI(3,5)P-2 production by PIKfyve in vivo.

关键词： Penaeus vannamei   Olive (Olea europaea)   White spot syndrome virus (WSSV)   Phenoloxidase activity   Oxyhemocyanin  

摘要： The main goal of this study was to investigate the biochemical, hematological, and immunological impacts of olive (Olea europaea) leaf extract (OLE) in Penaeus vannamei experimentally infected by white spot syndrome virus (WSSV). A total of 160 juvenile whiteleg shrimp (11.1 +/- 0.2 g), obtained from a private sector in Hormozgan Province (Iran), were kept for two weeks to acclimatize to conditions in the facility aquarium. The health status of the shrimp was assured by random sampling before experiment action;PCR testing confirmed the absence of common shrimp diseases. Three groups, each consisting of 20 shrimp fed with three different doses of OLE (50, 100, 200 mg/kg of the shrimp biomass), and a positive control group (not feeding with OLE), were all orally subjected to a virus challenge two weeks later. For comparison, three negative control groups with 20 shrimp were fed three different doses of OLE, and another group was fed with a diet lacking OLE. The PCR test confirmed the presence of the WSS virus in the treatment and positive control groups, while the ne-gative control groups did not show any infections. The hemolymph of shrimp was taken on days 1, 8, and 22 from all groups after challenge for evaluation of hemolymph total protein, glucose, oxyhemocyanin (OxH), superoxide dismutase (SOD), phenoloxidase (PO) activity, coagulation time, and total hemocyte count (THC). Results showed that shrimp survival significantly increased up to 65% when fed with high doses of OLE for seven days. The maximum hemolymph total protein and glucose levels significantly belonged to the treatment that was challenged by WSSV without receiving OLE. The present findings indicate WSS infection caused a significant decrease in OxH level compared to that of the control groups. Therapeutic feeding with OLE could significantly decrease the SOD and PO activities, and the hemolymph clotting time. We did not see no remarckable effects of OLE on the total hemocyte count. In conclusion, th

关键词： RGIases Aspergillus aculeatinus   Camelina mucilage   RGI-type pectins  

摘要： Rhamnogalaturonans I (RGI) pectins, which are a major component of the plant primary cell wall, can be recalcitrant to digestion by commercial enzymatic cocktails, in particular during fruit juice clarification process. To overcome these problems and get better insights into RGI degradation, three RGI degrading enzymes (RHG: Endo-rhamnogalacturonase;ABF: alpha-Arabinofuranosidases;GAN: Endo-beta-1,4-galactanase) from Aspergillus aculeatinus were expressed in Pichia pastoris, purified and fully biochemically characterized. All three enzymes showed acidic pH optimum, and temperature optima between 40-50 degrees C. The Km values were 0.5 ***(-1), 1.64 ***(-1) and 3.72 ***(-1) for RHG, ABF, GAN, respectively. NMR analysis confirmed an endo-acting mode of action for RHG and GAN, and exo-acting mode for ABF. The application potential of these enzymes was assessed by measuring changes in viscosity of RGI-rich camelina mucilage, showing that RHG-GAN enzymes induced a decrease in viscosity by altering the structures of the RGI backbone and sidechains.

关键词： CtCYP45082C subfamily   Leucoanthocyanidins   Gene expression   Flavonoid biosynthesis   Carthamus tinctorius  

摘要： Flavonoids are a distinctive class of phenolic compounds known to be involved in plant growth, development and floral pigmentation. During the natural phenylalanine pathway, dihydroflavonol-4-reductase is the first committed enzyme that catalyzes the stereo-specific reduction of dihydroflavonols into ***, less attention has been given to studies explaining the evolution and function of dihydroflavonol-4-reductases in Carthamus tinctorius L. This study explains the first comprehensive genome-wide identification and functional characterization of putative dihydroflavonol 4-reductase in Carthamus tinctorius L. Altogether, 20 CtCYP45082C enzyme encoding genes have been identified in the Carthamus tinctorius genome. Phylogeney analysis revealed the clustering of CtCYP45082C sequences into five major clades illustrating the significant effects of evolutionary divergence across the plant kingdom. Further in silico analyses indicated that all enzyme-encoding CtCYP45082Cs contain fundamental cis-regulatory units and protein domains/motifs that are specifically conserved throughout eukaryotic CYP450 s. In addition, the transient expression of CtCYP45082C1 fused with green fluorescent protein in onion epidermal cells and tobacco leaves confirmed a clearly distinct subcellular localization to plasma membrane. Biochemical characterization of CtCYP45082C1 using the heterologous protein expression assay indicated that CtCYP45082C1 effectively catalyzes the reduction of cis-3,4-leucopelargonidin and dihydromyricetin in leucoanthocyanidin biosynthesis. Moreover, the transcript expression of 20 Carthamus tinctorius derived CYP45082C genes has also been analyzed by real-time quantitative PCR. Each mRNA transcript was detected, in general, in all the investigated tissues, but with different patterns except for CtCYP45082C17-20, indicating the potential role of CtCYP45082C gene family in the secondary metabolite biosynthesis of Carthamus tinctorius. Additionall

关键词： Depression   Inflammation   MRI   MR spectroscopy   Lipopolysaccharide   Glutamine   Astrocyte   VCR   Behavior  

摘要： Despite mounting evidence for the role of inflammation in Major Depressive Disorder (MDD), in vivo preclinical investigations of inflammation-induced negative affect using whole brain imaging modalities are scarce, precluding a valid model within which to evaluate pharmacological interventions. Here we used an E. coli lipopolysaccharide (LPS)-based model of inflammation-induced depressive signs in rats to explore brain changes using multimodal neuroimaging methods. During the acute phase of the LPS response (2 h post injection), prior to the emergence of a task-quantifiable depressive phenotype, striatal glutamine levels and splenial, retrosplenial, and peri-callosal hippocampal cortex volumes were greater than at baseline. LPS-induced depressive behaviors observed at 24 h, however, occurred concurrently with lower than control levels of striatal glutamine and a reversibility of volume expansion (i.e., shrinkage of splenial, retrosplenial, and peri-callosal hippocampal cortex to baseline volumes). In both striatum and hippocampus at 24 h, mRNA expression in LPS relative to control animals demonstrated alterations in enzymes and transporters regulating glutamine homeostasis. Collectively, the observed behavioral, in vivo structural and metabolic, and mRNA expression alterations suggest a critical role for astrocytic regulation of inflammation-induced depressive behaviors.