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关键词： Wildfires   Post-fire runoffs   Freshwater invertebrate shredder   Oxidative and neuronal stress   Metals and PAHs  

摘要： Forests in Mediterranean Europe including Portugal are highly susceptible to wildfires. Freshwaters are often exposed to post-wildfire contamination that contains several toxic substances, which may impose risk to freshwater organisms and ecosystem functions. However, knowledge on the impacts of postwildfire runoffs from different origins on freshwater biota is scarce. In forest streams, invertebrate shredders have a major contribution to aquatic detrital-based food webs, by translocating energy and nutrients from plant-litter to higher trophic levels. We investigated the leaf consumption behaviour and the responses of oxidative and neuronal stress enzymatic biomarkers in the freshwater invertebrate shredder Allogamus ligonifer after short-term exposure (96 h) to post-wildfire runoff samples from Pinus and Eucalyptus plantation forests and stream water from a burnt catchment in Portugal. Chemical analyses indicated the presence of various metals and PAHs at considerable concentrations in all samples, although the levels were higher in the runoff samples from forests than in the stream water. The shredding activity was severely inhibited by exposure to increased concentrations of post-wildfire runoff samples from both forests. The dose-response patterns of enzymatic biomarkers suggest oxidative and neuronal stress in the shredders upon exposure to increasing concentrations of post-wildfire runoffs. The impacts were more pronounced for the runoffs from the burnt forests. Moreover, the response patterns suggest that the energy from the feeding activity of shredders might have contributed to alleviate the stress in A. ligonifer. Overall, the outcomes suggest that the post-wildfire contamination can induce sublethal effects on invertebrate shredders with impacts on key ecological processes in streams. (C) 2020 Elsevier Ltd. All rights reserved.

关键词： Arbuscular mycorrhizal fungi   Salinity   Ligustrum vicaryi   Nutrient uptake   Soluble protein  

摘要： Salt stress has become a major threat to plant growth. Arbuscular mycorrhizal fungi (AMF) are considered as bioameliorators and can modulate plant growth in various ways. However, few studies have addressed whether AMF could mediate the detrimental effects of salinity on Ligustrum vicaryi plants. In this study, inoculated (colonization with two AMF, Rhizophagus intraradices (Ri) and Funneliformis mosseae (Fm), alone and in combination) and non-inoculated (NM) L. vicaryi plants were subjected to three levels of NaCl salinity (0, 50 and 200 mM NaCl) to examine the interactive effects on the growth, chlorophyll fluorescence parameters and biochemical parameters of plants in a greenhouse experiment. The results showed that salinity stress had significanlty decreased the total dry weight of L. vicaryi plants. However, with Ri inoculation, the total dry weight, F-v/F-m, Yield, qP, the nutrient contents of P, K+, Mg2+, Zn2+, the K+:Na+ ratio and soluble protein content were considerably increased, while tissue Na+ content and shoot:root Na+ ratio were decreaed under saline conditions. It is suggested that mycorrhizal fungi can alleviate the detrimental effects of salt stress on L. vicaryi plants. Furthermore, the results also provide evidence that the mediation of N, Ca2+, Zn2+, Mg2+ and soluble protein content would be probably the main mechanism underlying salt tolerance in mycorrhizal plants.

关键词： desynchronosis modeling   jetlag   cosinor analysis   biorhythms  

摘要： This article describes models for the study of acute desynchronosis: jetlag syndrome and acute desynchronosis under physical stress for possible pharmacological correction of these disorders. The cosinor analysis allowed assessing significance of changes in biological rhythms in 2 biological models: the jetlag-type diurnal rhythm shift model and the model with changed light mode. The revealed changes in the rhythms of biochemical parameters in the blood serum of animals with acute desynchronosis indicate significant changes in the intensity of carbohydrate-lipid metabolism, which affected the processes of cell bioenergetics. These changes are most pronounced in the group of animals that were kept under conditions of constant darkness, which can serve as a marker of the initial stage of pathological desynchronosis. The jetlag-type model can be used to evaluate the effectiveness of the pharmacological correction of physiological desynchronosis. The model with modified light regimen can be used for evaluation of the effectiveness of pharmacological correction of pathological desynchronosis.

关键词： Saccharomyces cerevisiae   Crystal structure   1-Cys Peroxiredoxin   Thioredoxin   Mitochondria  

摘要： Background: ScPrx1 is a yeast mitochondrial 1-Cys peroxiredoxins (Prx), a type of Prx enzyme which require thiol-containing reducing agents to resolve its peroxidatic cysteine. ScPrx1 plays important role in protection against oxidative stress. Mitochondrial thioredoxin ScTrx3 and glutathione have been reported to be the physiological electron donor for ScPrx1. However, the mechanism underlying their actions, especially the substrate recognition of ScPrx1 requires additional elucidation. METHODS: The structure of ScPrx1 was obtained through crystallization experiments. The oligomeric state of ScPrx1 was monitored by Blue-Native PAGE. Mutations were generated by the QuikChange PCR-based method. The ScPrx1 activity assay was carried out by measuring the change of 340 nm absorption of the NADPH oxidation. Results: ScPrx1 exist as a homodimer in solution. The structure adopts a typical Prx-fold core which is preceded by an N-terminal beta-hairpin and has a C-terminal extension. Mutations (Glu94Ala, Arg198Ala and Trp126) close to the active site could enhance the catalytic efficiency of ScPrx1 while His83Ala and mutations on alpha 4-beta 6 region exhibited reduced activity. The biochemical data also show that the deletion or mutations on ScPrx1 C-terminal have 2-4.56 fold increased activity. Conclusion: We inferred that conformational changes of ScPrx1 C-terminal segment were important for its reaction, and the alpha 4-beta 6 loop regions around the ScPrx1 active sites were important for the catalytic function of ScPrx1. Collectively, these structural features provides a basis for understanding the diverse reductant species usage in different 1-Cys Prxs.

关键词： Purification   Characterization   Phenoloxidase   Endogenous inhibitor  

摘要： Phenoloxidase system is a crucial component of insect innate immunity which contribute to oxidize phenols to quinones and to generate reactive oxygen and nitrogen intermediates. In the current study, a phenoloxidase (PO) was extracted by hemocyte lysate preparation and purified through ammonium sulfate precipitation, Sepharyl G-100, and DEAE-Cellulose fast flow columns. At the end of the purification process, an enzyme was purified with a specific activity of 0.462 U/mg protein, recovery of 40.47%, purification fold of 14.43 and molecular weight of similar to 78.7 kDa. The optimal activity was recorded at pH 7 while the optimal temperature was recorded at 30-35 degrees C, 35 degrees C and 25-35 degrees C, using L-dihydroxyphenylalanine, hydroquinone, and pyrocatechol, respectively. The highest V-max of PO was obtained using L-dopa while the lowest K-m value was gained using hydroquinone. Among used synthetic inhibitors of ethylenediaminetetraacetic acid (EDTA), diethyldithiocarbamate (DTC), N, N,N0,N0-tetraacetic acid (EGTA) and triethylenetetramine hexaacetic acid (TTHA), EDTA and DTC inhibited more than 60% of the enzyme activity. Moreover, an endogenous phenoloxidase inhibitor (POI) was purified by twice processing of Sepharyl G-100 chromatography with the molecular weight of similar to 52 kDa. The IC50 of POI was found 31.3 mg against the purified PO of C. perspectalis and led to a higher value of K-m. Finally, larval injection by DTC and POI demonstrated significant inhibition of PO over the time of exposure. A comprehensive understanding of insect's POs may better clarify the ways of their survival within infected areas and to potentially target them by specific and selective compounds.

关键词： AMPK   GC-qTOF-MS   Metformin   mGPDH   Molecular docking   Polyphenols  

摘要： The use of Kigelia africana plant is beneficial in many medicinal applications. This study investigated the chemical compounds as well as antioxidant and antidiabetic activities of KA fruits in vitro and in vivo. Molecular docking study was used to predict the activities of these metabolites in relation to diabetes mellitus. From the result of GC-qTOF-MS, phenol-2,4-bis(1,1-dimethylethyl)-, benzene propanoic acid-3,5-bis(1,1-dimethylethyl)-4-hydroxymethylester, naphthalene-2-methyl-, and oxalic acid-4-chlorophenyl nonyl-ester were newly identified and revealed a strong binding affinity of − 6.1, − 6.3, − 6.8, and − 6.2 kcal/mol respectively. The hexane and ethyl acetate fractions had the highest antioxidant activities with 0.14 and 0.025 mg/mL for DPPH;91.31 and 99.20 mg AAE/g for FRAP;and 80.61 and 98.88 mg AAE/g for TPC, respectively. Hexane fraction (HF) had the lowest IC₅₀ value (1.97 mg/mL) against α-amylase. At low and middle doses, HF showed significant ameliorative activities by restoring islet cells, increasing the number of β cells, and reducing fasting blood glucose levels. Significant differences were observed in the activities of GGT and G-6-PDH. KA fruit exhibited high antidiabetic and antihyperglycemic activities in STZ-induced diabetic rats. According to molecular docking study, the use of the base structure of 2,4-ditert-butylphenol identified from K. africana fruit may serve as the novel approach to the treatment of diabetes mellitus. Graphical abstract: [Figure not available: see fulltext.]. © 2020, Springer-Verlag London Ltd., part of Springer Nature.

关键词： analytical error   control limit   QC validation   RPT   statistical QC  

摘要： Background Repeat patient testing-based quality control (RPT-QC) is a form of statistical QC and an alternative to commercial quality control materials (QCM). Objective This study investigated the suitability of canine heparinized plasma for use in RPT-QC and assessed the predicted performance of RPT-QC for the detection of analytical error in chemistry testing. Methods The stability of canine plasma for RPT-QC was investigated via storage at two temperatures for three or six time points. Storage data were analyzed using repeated measures ANOVA and by comparing results for stored specimens to baseline data using predetermined criteria. To generate RPT-QC limit-setting and -validation data, leftover plasma was prospectively measured. Once control limits were established, these were challenged by measuring specimens for which the repeat aliquot had been manipulated to mimic analytical error. Finally, the predicted performance of RPT-QC and QCM-QC with four control rules was investigated using Westgard's EZ Rules 3. Results Refrigerated storage of canine plasma for 7 days allowed mild changes facilitating RPT-QC. RPT-QC limits for 12 of 17 common measurands were validated. Validated limits successfully flagged differences from manipulated specimen pairs as "error." The predicted performance of RPT-QC for analytical error detection (represented by smallest achievable allowable total error, given a probability of error detection >= 85% and a probability of false rejection <= 5%) for four common control rules is comparable to that of QCM-QC. Conclusions This study provides evidence that RPT-QC using canine heparinized plasma refrigerated for 7 days can be used with simple control rules and low numbers of control materials, suggesting RPT-QC is applicable to both reference and in-clinic laboratory settings.

关键词： Biochemical processes   Bioreactor landfill   Coupled processes   Elevated temperatures   Heat generation   Landfill gas  

摘要： A coupled bio-thermal (BT) model is proposed and validated for the prediction of long-term biochemical and thermal behavior of municipal solid waste (MSW) in landfills. The biochemical and thermal behavior of the waste was modeled using a two-stage anaerobic degradation model and diffusive heat transport model, respectively. A temperature function that accounts for the inhibitory effect of non-optimum temperatures on the microbial growth was proposed to simulate the coupled effects of biochemical and thermal behavior of waste in landfills. Six numerical simulation cases representing conventional and bioreactor landfill conditions were performed on a typical full-scale landfill cell model to determine the spatial and temporal variation in the long-term biochemical and thermal characteristics of waste in landfills. The results from the numerical analyses show that incorporating the effect of temperature of waste in the modeling of biodegradation of waste in landfills plays a significant role in realistically predicting the long-term biochemical and thermal regime in MSW landfills. The proposed BT model captures the key trends in the landfill gas (LFG) production and waste temperatures typically observed in actual full-scale landfills. Elevated waste temperatures were predicted especially in the bioreactor landfill cases suggesting that rapid decomposition of waste induces high heat generation rates;however, the elevated temperatures were short-lived.

关键词： Cardiac damage   Lead (Pb) intoxication   Metabolic enzymes   Oxidative insult  

摘要： Regarding the potential interrelation between lead (Pb) toxicity and cardiovascular diseases, the current investigation aims to study the alterations of some metabolic enzyme activities as well as oxidative stress-related parameters in the myocardium of lead-exposed mice. Twelve male mice are distributed arbitrarily into two equal groups. First group served as control. Mice in group 2 received water containing 1000 mg L⁻¹ lead acetate. The results revealed that Pb-treated mice had significantly higher values of cardiac troponin I and creatine kinase MB as compared with the control group. Moreover, Pb-treated mice had comparatively lower values of cardiac superoxide dismutase, catalase, and glutathione. Considerable rise of cardiac lactate dehydrogenase and alanine aminotransferase as well as malondialdehyde was also detected in Pb-exposed group. However, the influences of lead poisoning on other measured indices including protein carbonyls, ferric reducing antioxidant power, glutathione peroxidase, alkaline phosphatase, and aspartate aminotransferase were not significant compared with controls. The current data show that lead exposure in mice results in histochemical disturbances in heart tissue which are manifested by decreased quantities of some endogenous antioxidants, increased levels of lipid peroxidation and some enzyme activities, as well as increase of measured plasma indices of cardiac damage. These findings suggested that some biological systems of heart tissue can be influenced following Pb exposure which should be considered in the pathogenesis of Pb-induced cardiac toxicity. © 2020, Springer-Verlag London Ltd., part of Springer Nature.