22,374 research outputs found

    Organisation and control of ascorbate biosynthesis pathway in plants

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    Ascorbate, also known as vitamin C, plays fundamental roles in human health. However, we are unable to synthesise ascorbate due to a series of accumulated mutations in the last enzyme of the pathway. Therefore, fruits and vegetables become the dietary source of ascorbate, hence being called a vitamin. In plants, ascorbate plays a plethora of roles provinding both biotic and abiotic stress resistance in plants. Although it is known that VTC2 (GDP-L-Galactose Phosphorylase) is the bottleneck of the pathway, little information is available on the basis of how it happens. In this thesis, I confirmed it by several two-by-two combinations as well as expressing the whole pathway. Furthermore, I have shown that this translation fusions are functional and locate in cytosol and nuclei, with the exception of GME and GLDH. Since ascorbate is essential in the response to stress in plants, and the enzymes involved in its biosynthesis locate in the same subcellular region, it was tempting to suggest that they may associate like in other pathways. Our protein-protein association assays suggest that they associate, further supported by the fact that the first and the last cytosolic enzymes immunoprecipitate together, although it deserves further investigation. Since VTC2 was found to be limiting ascorbate biosynthesis, we sought to understand the basis behind this fact. We found that the level of VTC2 expression is very low compared to the expression of the other components of the pathway. However, it was high enough to complement vtc2 phenotype therefore suggesting that keeping its protein amount little expressed in the first control point of the pathway. In addition, we observed that VTC2 is degraded rapidly just after entering the night period, which was further elucidated to be controlled by 26S proteasome

    Nanostructured Systems for Electrocatalysis of Reduction Reactions for Energy Conversion Applications

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    Oxygen Reduction Reaction (ORR) requires a platinum-based catalyst to reduce the activation barrier. One of the most promising materials as alternative catalysts are carbon-based, graphene and carbon nanotubes (CNT) derivatives. ORR on a carbon-based substrate involves the less efficient two electrons process and the optimal four electrons process. New synthetic strategies to produce tunable graphene-based materials utilizing graphene oxide (GO) as a base inspired the first part of this work. Hydrogen Evolution Reaction (HER) is a slow process requiring also platinum or palladium as catalyst. In the second part of this work, we develop and use a technique for Ni nanoparticles electrodeposition using NiCl2 as precursor in the presence of ascorbate ligands. Electrodeposition of nano-nickel onto flat glassy carbon (GC) and onto nitrogen-doped reduced graphene oxide (rGO-N) substrates are studied. State of the art catalysts for CO2RR requires rare metals rhenium or rhodium. In recent years significant research has been done on non-noble metals and molecular systems to use as electro and photo-catalysts (artificial photosynthesis). As Cu-Zn alloys show good CO2RR performance, here we applied the same nanoparticle electrosynthesis technique using as precursors CuCl2 and Cl2Zn and observed successful formation of the nanoparticles and a notable activity in presence of CO2. Using rhenium complexes as catalysts is another popular approach and di-nuclear complexes have a positive cooperative effect. More recently a growing family of pre-catalysts based on the earth-abundant metal manganese, has emerged as a promising, cheaper alternative. Here we study the cooperative effects of di-nuclear manganese complexes derivatives when used as homogeneous electrocatalysts, as well as a rhenium functionalized polymer used as heterogeneous electrocatalyst

    Characterization of physiochemical and molecular responses of sage (Salvia officinalis) to ozone-induced oxidative stress

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    Tropospheric ozone (O3) is a major air pollutant causing negative effects on health of living organisms, as well as the third most powerful anthropogenic greenhouse gas. Despite numerous legislatory attempts aimed to control emissions of its precursors, O3 is still among the major air pollutants worldwide, especially in areas with elevated temperatures such as the Mediterranean basin, where it frequently exceeds the World Health Organization (WHO) guideline average values (i.e., 8 hours a day at most above 100 ╬╝gÔÇëm-3). Four decades of research on O3-vegetation effects have shown that excessive uptake of this gas and the consequent accumulation of reactive oxygen species (ROS) induce detrimental effects such as reduction of photosynthesis and growth, partial stomatal closure, cell dehydration, excessive excitation energy, accelerated leaf senescence, and appearance of chlorotic/necrotic leaf injuries, that overall result in reduction of plant yield and productivity. However, plants possess a forceful and multifarious antioxidant system composed of enzymatic reactions (e.g., superoxide dismutase, catalase and ascorbate peroxidase) and non-enzymatic compounds (e.g., ascorbic acid and glutathione), which are involved in detoxification, removal and/or neutralization of ROS overproduction due to biotic and abiotic stresses. During the last decades, medicinal and aromatic plants have been extensively studied and found to be excellent sources of bioactive and health-promoting molecules. Most of these compounds are also beneficial for the plant itself by their significant role in plant resistance. Salvia officinalis L. (sage) is one of the most well-known aromatic herbs. Native of southern Europe, it is largely cultivated in the Mediterranean countries due to its high ability to cope with environmental stressors. Since the impact of O3 on medicinal plants remains poorly understood, the overall scope of this research work was to investigate the responses of S. officinalis to a single pulse and a chronic exposure of O3. Firstly, S. officinalis plants were investigated to assess the role of signalling molecules, phytohormones and transcription factors under a single pulse of O3 (200 ppb of O3 for 5 h). The O3 concentration adopted in this experiment induced only a transient oxidative burst. Furthermore, signalling molecules resulted as good mediators of cell survival by providing better antioxidant defences and regenerating active reduced forms, whereas phytohormones were not involved in the perception and transduction of O3 stress. WRKY trancription factors seemed to act as promoter elements of the apoplastic response to ROS generation, regulating oxidative protection and providing O3-stress tolerance. Overall, this first dataset suggested that sage evolved several biochemical mechanisms to cope with such adverse environmental conditions. Following the results came out from this first experiment, the antioxidant mechanisms adopted by S. officinalis under the same single pulse O3 exposure (i.e., 200 ppb of O3 for 5 h) were also investigated. This study demonstrated that O3 induced some photosynthetic impairments in sage leaves during the exposure, but plants quickly recovered after the fumigation, confirming the tolerance of this species to the pollutant. Indeed, slightly higher levels of lipid peroxidation were only observed at the end of the exposure, and the antioxidant capacity was overall increased by the pollutant. The antioxidant response seemed to be finely regulated by the activation/suppression of specific antioxidants at the different times of analysis, both during and after the exposure. A key role in the antioxidant response seemed to be played by the Halliwell-Asada cycle. Actually, another major scope of the present study was to test the capability of full-range (350-2500 nm) reflectance spectroscopy to rapidly and non-destructively characterize responses of asymptomatic sage leaves to the single pulse of O3. Using partial least squares regression, spectral models were developed for the estimation of several traits related to photosynthesis, the oxidative pressure induced by O3, and the antioxidant mechanisms adopted by plants to cope with the pollutant. Physiological traits were well predicted by spectroscopic models [average model goodness-of-fit for validation (R2): 0.65-0.90], whereas lower prediction performances were found for biochemical traits (R2: 0.42-0.71). Furthermore, even in the absence of visible symptoms, comparing the full-range spectral profiles, it was possible to distinguish with accuracy plants maintained under charcoal-filtered air (i.e., controls) from those exposed to O3. The main objective of the third experiment was to give a thorough description of the effects of an O3 pulse at a lower concentration (120 ppb for 5 h) on the phenylpropanoid metabolism of S. officinalis, at both biochemical and molecular levels. Variable O3-induced changes were observed over time among the detected phenylpropanoid compounds (mostly identified as phenolic acids and flavonoids), likely because of their extraordinary functional diversity. Furthermore, decreases of the phenylalanine ammonia-lyase (PAL), polyphenol oxidase (PPO) and rosmarinic acid synthase (RAS) activities (i.e., key enzymes of phenolic biosynthetic pathways) were reported during the first hours of treatment, probably due to an O3-induced oxidative damage to proteins. Both PAL and PPO activities were also suppressed at 24 h from the beginning of the exposure, whereas an enhanced RAS activity occurred at the end of the treatment and at the recovery time, suggesting that specific phenylpropanoid pathways were activated. The increased RAS activity was accompanied by the up-regulation of the transcript levels of genes like RAS, tyrosine aminotransferase and cinnamic acid 4-hydroxylase. In conclusion, sage faced the O3 pulse by regulating the activation of the phenolic biosynthetic route as an integrated defence mechanism. Finally, the S. officinalis-O3 interaction was investigated from a different angle than previous experiments. Eliciting of plants consists in the application of chemical, physical and biological factors inducing stressful conditions to trigger defence mechanisms and thus the production of various bioactive compounds and phytochemicals with beneficial health effects. Thus, a final study was performed to weekly assess the effects of a chronic O3 exposure (120 ppb of O3 for 36 consecutive days, 5 h day-1) on the phenolic and volatile organic compounds (VOC) profiles of sage leaves, also relating the compositions of these compounds with the changing antioxidant activity induced by the air pollutant. The effects of O3 exposure on the VOC composition, yield and antioxidant capacity of essential oils (EOs) obtained from sage leaves were also evaluated. We identified 17 phenolic compounds in S. officinalis leaves (phenolic acids and flavonoids), and 62 and 56 VOCs emitted by leaves and EOs, respectively (monoterpene hydrocarbons, oxygenated monoterpenes, sesquiterpene hydrocarbons, two oxygenated sesquiterpenes and nine non-terpene derivatives). Ozone exposure resulted in an overall accumulation of phenolic compounds. In terms of VOCs, O3 mainly decreased the emission of monoterpenes, while increased the production of sesquiterpenes and non-terpene derivatives (from both leaves and EOs). These O3-induced accumulations were mainly triggered during the first weeks of exposure whereas they disappeared at the last time of analysis, suggesting that sage plants finally lost their ability or interest in investing in this response strategy, and indicating that reaching too high doses of O3 resulted in slow inhibition of secondary metabolites. The antioxidant capacity of all tested extracts resulted increased by O3 exposure. These outcomes support our speculation on the application of O3 for a limited period (i.e., a maximum of four weeks, at the investigated concentration) as a potential tool to improve the quality of sage leaf extracts

    Phytotoxicity assessment of nuclear waste from Kaštela bay

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    Podru─Źje Ka┼ítelanskog zaljeva desetlje─çima je bilo sredi┼íte industrijskih aktivnosti u Dalmaciji. U blizini biv┼íe tvornice Jugovinil nalazi se napu┼íteni deponij pepela i ┼íljake s pove─çanom koncentracijom prirodnih radionuklida 238U, 235U, 226Ra i 210Pb. Njihova prisutnost iznad dozvoljenih koncentracija mo┼że uzrokovati negativne posljedice na hranidbene mre┼że i predstavlja ugrozu za prirodne resurse poput podzemnih voda, morske obale i autohtonog biljnog pokrova. Cilj ovog rada bila je toksikolo┼íka procjena tr┼ílje (Pistacia lentiscus L.) i alepskog bora (Pinus halepensis Mill.) sakupljenih s podru─Źja talo┼żnice biv┼íe tvornice. Kao indikatori toksi─Źnosti mjereni su biokemijski pokazatelji toksi─Źnosti - sadr┼żaj malondialdehida, fotosintetskih pigmenata te aktivnosti enzima superoksid dismutaze (SOD), katalaze (CAT), askorbat peroksidaze (APX) i glutation-S-transferaze (GST). Rezultati istra┼żivanja pokazali su statisti─Źki zna─Źajne razlike u sadr┼żaju proteina, fotosintetskih pigmenata i aktivnosti pojedinih enzima u listovima tr┼ílje, a posebice alepskog bora s lokacije Jugovinil u odnosu na biljke s kontrolne lokacije. Rezultati fitotoksikolo┼íke analize tr┼ílje i alepskog bora ukazuju na negativan utjecaj odlo┼żenog pepela i ┼íljake s povi┼íenim koncentracijama prirodnih radionuklida na novonastale biljne zajednice.For decades, the area around Ka┼ítela bay was known as the center of industrial activities in Dalmatia County. Radioactive coal ash and slag with high 238U, 235U, 226Ra, 210Pb values were ilegally disposed around ex-chemical factory Jugovinil. High presence of these elements can cause negative consequences on food chains and natural resources like groundwater, sea coast and native plant species. The aim of this study was toxicological evaluation of pine (Pinus helepensis Mill.) and mastic tree (Pistacia lentiscus L.) collected from coal ash and slag landfill. The chlorophylls and carotenoids, malondialdehyde and enzyme activities (superoxide dismutase, ascorbate peroxidase, catalase and glutathion-S-transferase) were used as biochemical toxicity indicators. The results showed statistically significant differences in relative protein and pigment abundance and individual enzyme activities in both pine and mastic tree leaves from contaminated location compared to those from control location. The results of phytotoxicity analysis of pine and mastic tree indicate negative influence of deposited coal ash and slag with elevated concentrations of naturally occurring radionuclides on newly formed plant communities

    Self-Powered Wearable Gas Sensors Based on lÔÇĹAscorbate-Treated MXene Nanosheets and SnO<sub>2</sub> Nanofibers

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    Self-powered sensing devices have aroused the regime of flexible, portable, and wearable gas sensors due to their economic and environmentally friendly nature. Highly active two-dimensional MXene with high metallic conductivity, large surface area, and surface chemistry has shown great potential for sensing applications except for their oxidation degradation. The present work reports the development of a humidity tolerant self-powered gas sensor comprising nanocomposite of sodium l-ascorbate-treated MXene and SnO2 nanofiber-based gas sensor and piezoelectric pressure sensor (PPs). The interfacial engineering of MXene with SnO2 was significantly found to enhance both the pressure sensitivity and room-temperature NO2 gas sensing performance. The SnO2/MXene nanocomposite-based gas sensor exhibits Ôł╝8- and 34-fold response toward NO2 gas as compared to SnO2 nanofibers and MXene sheets, respectively, along with a lower detection limit of 0.03 ppb NO2 and power consumption as low as 1.2 ╬╝W. Moreover, the SnO2/MXene nanocomposite-based PPs exhibits a high sensitivity of 2.088 kPaÔÇô1 under the pressure range of 1.63ÔÇô6.23 kPa with a fast response time (265 ms) and recovery time (75.5 ms). In addition, the PPs can produce a power density of 21.80 mW mÔÇô2, sufficient enough to drive the gas sensor and demonstrate its potential application for self-powered wearable gas sensors

    Differential responses in some quinoa genotypes of a consortium of beneficial endophytic bacteria against bacterial leaf spot disease

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    Many effective plant-microbe interactions lead to biological changes that can stimulate plant growth and production. This study evaluated the effect of the interaction between quinoa (Chenopodium quinoa Willd.) and endophytic bacterial strains on differential responses under biotic stress. Four strains of endophytic bacteria were used to inoculate three quinoa genotypes. Endophytic bacteria, isolated from the endosphere of healthy genotypes of quinoa plants, were used to evaluate their biocontrol activity against Pseudomonas syringae on quinoa plants, which causes leaf spot disease, depending on some different parameters. Quinoa genotype plants were treated with four treatments: pathogenic bacteria only (T1), internal bacteria only (T2), pathogenic bacteria + endogenous bacteria (T3), and untreated as the control (T4). The results indicated that there was a significant difference between chlorophyll content index of infected plants without bioagent (untreated) compared to plants bio-inoculated with endophytic bacteria. The highest mean disease incidence was on the plants without bacterial inoculum (90, 80, and 100%) for quinoa genotypes G1, G2, and G3, respectively. The results showed that there were significant differences in the weight of grains/plant, as the value ranged from 8.1 to 13.3ÔÇëg when treated with pathogens (T1) compared to the treatment with pathogens and endogenous bacteria (T3), which ranged from 11.7 to 18.6ÔÇëg/plant. Decreases in total aromatic amino acids appeared due to the pathogen infection, by 6.3, 22.8, and 24.1% (compared to the control) in G1, G2, and G3, respectively. On the other hand, genotype G3 showed the highest response in the levels of total aromatic and total neutral amino acids. The endophytic strains promoted quinoa seedling growth mainly by improving nutrient efficiency. This improvement could not be explained by their ability to induce the production of amino acids, showing that complex interactions might be associated with enhancement of quinoa seedling performance by endophytic bacteria. The endophytic bacterial strains were able to reduce the severity of bacterial leaf spot disease by 30, 40, and 50% in quinoa genotypes G1, G2, and G3, respectively, recording significant differences compared to the negative control. The results indicated that, G1 genotype was superior in different performance indicators (pathogen tolerance index, yield injury %, superiority measure and relative performance) for grain weight/plant under pathogen infection condition when treated with endophyte bacteria. Based on this study, these bacterial strains can be used as a biotechnology tool in quinoa seedling production and biocontrol to diminish the severity of bacterial leaf spot disease

    Serum creatinine and urea assays on Atellica® CH and Architect® ci4100: method comparison

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    Serum creatinine and urea are markers of renal function usually measured in conjunction. This study aims to evaluate the comparability of a new analyzer incorporated to our laboratory, Atellica┬« with the established analyzer, Architect ┬« ci 4100 in serum creatinine and urea assays. We ran 110 tests for creatinine and 107 for urea. In both analyzers, serum creatinine assay is based on the Jaffe reaction while urea measurement is based on the Roch-Ramel enzymatic reaction. Linear association between methods was evaluated using Pearson's correlation coefficient. Methods comparability was assessed using Passing-Bablok and Deming linear regression. Differences between analyzers were evaluated using Bland-Altman plot. For serum creatinine, regression equations are Atellica = 0.9721 x Architect - 2.7282 (Passing & Bablok) and Atellica = 0.8884 x Architect + 1.3456 (Deming). The mean difference between the two methods is -11.7 ┬Ámol/L as indicated by Bland-Altman plot. For urea, regression lines are expressed as Atellica = 1.0252 x Architect ÔÇô 0.1609 (Passing-Bablok) and Atellica = 1.1424 x Architect ÔÇô 0.9532 (Deming). Bland-Altman plot presented a mean difference of -0.1 mmol/L. These results could be described as a very good agreement between the two methods, the two analyzers could be used interchangeably. DOI: http://dx.doi.org/10.5281/zenodo.754215

    Pollution-induced community tolerance in freshwater biofilms ÔÇô from molecular mechanisms to loss of community functions

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    Exposure to herbicides poses a threat to aquatic biofilms by affecting their community structure, physiology and function. These changes render biofilms to become more tolerant, but on the downside community tolerance has ecologic costs. A concept that addresses induced community tolerance to a pollutant (PICT) was introduced by Blanck and W├Ąngberg (1988). The basic principle of the concept is that microbial communities undergo pollution-induced succession when exposed to a pollutant over a long period of time, which changes communities structurally and functionally and enhancing tolerance to the pollutant exposure. However, the mechanisms of tolerance and the ecologic consequences were hardly studied up to date. This thesis addresses the structural and functional changes in biofilm communities and applies modern molecular methods to unravel molecular tolerance mechanisms. Two different freshwater biofilm communities were cultivated for a period of five weeks, with one of the communities being contaminated with 4 ╬╝g L-1 diuron. Subsequently, the communities were characterized for structural and functional differences, especially focusing on their crucial role of photosynthesis. The community structure of the autotrophs was assessed using HPLC-based pigment analysis and their functional alterations were investigated using Imaging-PAM fluorometry to study photosynthesis and community oxygen profiling to determine net primary production. Then, the molecular fingerprints of the communities were measured with meta-transcriptomics (RNA-Seq) and GC-based community metabolomics approaches and analyzed with respect to changes in their molecular functions. The communities were acute exposed to diuron for one hour in a dose-response design, to reveal a potential PICT and uncover related adaptation to diuron exposure. The combination of apical and molecular methods in a dose-response design enabled the linkage of functional effects of diuron exposure and underlying molecular mechanisms based on a sensitivity analysis. Chronic exposure to diuron impaired freshwater biofilms in their biomass accrual. The contaminated communities particularly lost autotrophic biomass, reflected by the decrease in specific chlorophyll a content. This loss was associated with a change in the molecular fingerprint of the communities, which substantiates structural and physiological changes. The decline in autotrophic biomass could be due to a primary loss of sensitive autotrophic organisms caused by the selection of better adapted species in the course of chronic exposure. Related to this hypothesis, an increase in diuron tolerance has been detected in the contaminated communities and molecular mechanisms facilitating tolerance have been found. It was shown that genes of the photosystem, reductive-pentose phosphate cycle and arginine metabolism were differentially expressed among the communities and that an increased amount of potential antioxidant degradation products was found in the contaminated communities. This led to the hypothesis that contaminated communities may have adapted to oxidative stress, making them less sensitive to diuron exposure. Moreover, the photosynthetic light harvesting complex was altered and the photoprotective xanthophyll cycle was increased in the contaminated communities. Despite these adaptation strategies, the loss of autotrophic biomass has been shown to impair primary production. This impairment persisted even under repeated short-term exposure, so that the tolerance mechanisms cannot safeguard primary production as a key function in aquatic systems.:1. The effect of chemicals on organisms and their functions .............................. 1 1.1 Welcome to the anthropocene .......................................................................... 1 1.2 From cellular stress responses to ecosystem resilience ................................... 3 1.2.1 The individual pursuit for homeostasis ....................................................... 3 1.2.2 Stability from diversity ................................................................................. 5 1.3 Community ecotoxicology - a step forward in monitoring the effects of chemical pollution? ................................................................................................................. 6 1.4 Functional ecotoxicological assessment of microbial communities ................... 9 1.5 Molecular tools ÔÇô the key to a mechanistic understanding of stressor effects from a functional perspective in microbial communities? ...................................... 12 2. Aims and Hypothesis ......................................................................................... 14 2.1 Research question .......................................................................................... 14 2.2 Hypothesis and outline .................................................................................... 15 2.3 Experimental approach & concept .................................................................. 16 2.3.1 Aquatic freshwater biofilms as model community ..................................... 16 2.3.2 Diuron as model herbicide ........................................................................ 17 2.3.3 Experimental design ................................................................................. 18 3. Structural and physiological changes in microbial communities after chronic exposure - PICT and altered functional capacity ................................................. 21 3.1 Introduction ..................................................................................................... 21 3.2 Methods .......................................................................................................... 23 3.2.1 Biofilm cultivation ...................................................................................... 23 3.2.2 Dry weight and autotrophic index ............................................................. 23 3.2.4 Pigment analysis of periphyton ................................................................. 23 3.2.4.1 In-vivo pigment analysis for community characterization ....................... 24 3.2.4.2 In-vivo pigment analysis based on Imaging-PAM fluorometry ............... 24 3.2.4.3 In-vivo pigment fluorescence for tolerance detection ............................. 26 3.2.4.4 Ex-vivo pigment analysis by high-pressure liquid-chromatography ....... 27 3.2.5 Community oxygen metabolism measurements ....................................... 28 3.3 Results and discussion ................................................................................... 29 3.3.1 Comparison of the structural community parameters ............................... 29 3.3.2 Photosynthetic activity and primary production of the communities after selection phase ................................................................................................. 33 3.3.3 Acquisition of photosynthetic tolerance .................................................... 34 3.3.4 Primary production at exposure conditions ............................................... 36 3.3.5 Tolerance detection in primary production ................................................ 37 3.4 Summary and Conclusion ........................................................................... 40 4. Community gene expression analysis by meta-transcriptomics ................... 41 4.1 Introduction to meta-transcriptomics ............................................................... 41 4.2. Methods ......................................................................................................... 43 4.2.1 Sampling and RNA extraction................................................................... 43 4.2.2 RNA sequencing analysis ......................................................................... 44 4.2.3 Data assembly and processing................................................................. 45 4.2.4 Prioritization of contigs and annotation ..................................................... 47 4.2.5 Sensitivity analysis of biological processes .............................................. 48 4.3 Results and discussion ................................................................................... 48 4.3.1 Characterization of the meta-transcriptomic fingerprints .......................... 49 4.3.2 Insights into community stress response mechanisms using trend analysis (DRomicÔÇÖs) ......................................................................................................... 51 4.3.3 Response pattern in the isoform PS genes .............................................. 63 4.5 Summary and conclusion ................................................................................ 65 5. Community metabolome analysis ..................................................................... 66 5.1 Introduction to community metabolomics ........................................................ 66 5.2 Methods .......................................................................................................... 68 5.2.1 Sampling, metabolite extraction and derivatisation................................... 68 5.2.2 GC-TOF-MS analysis ............................................................................... 69 5.2.3 Data processing and statistical analysis ................................................... 69 5.3 Results and discussion ................................................................................... 70 5.3.1 Characterization of the metabolic fingerprints .......................................... 70 5.3.2 Difference in the metabolic fingerprints .................................................... 71 5.3.3 Differential metabolic responses of the communities to short-term exposure of diuron ............................................................................................................ 73 5.4 Summary and conclusion ................................................................................ 78 6. Synthesis ............................................................................................................. 79 6.1 Approaches and challenges for linking molecular data to functional measurements ...................................................................................................... 79 6.2 Methods .......................................................................................................... 83 6.2.1 Summary on the data ............................................................................... 83 6.2.2 Aggregation of molecular data to index values (TELI and MELI) .............. 83 6.2.3 Functional annotation of contigs and metabolites using KEGG ................ 83 6.3 Results and discussion ................................................................................... 85 6.3.1 Results of aggregation techniques ........................................................... 85 6.3.2 Sensitivity analysis of the different molecular approaches and endpoints 86 6.3.3 Mechanistic view of the molecular stress responses based on KEGG functions ............................................................................................................ 89 6.4 Consolidation of the results ÔÇô holistic interpretation and discussion ............... 93 6.4.1 Adaptation to chronic diuron exposure - from molecular changes to community effects.............................................................................................. 93 6.4.2 Assessment of the ecological costs of Pollution-induced community tolerance based on primary production ............................................................. 94 6.5 Outlook ............................................................................................................ 9

    Alterations to cerebral perfusion, metabolite profiles, and neuronal morphology in the hippocampus and cortex of male and female mice during chronic exposure to a high-salt diet

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    Excess dietary salt reduces resting cerebral blood flow (CBF) and vascular reactivity, which can limit the fueling of neuronal metabolism. It is hitherto unknown whether metabolic derangements induced by high-salt-diet (HSD) exposure during adulthood are reversed by reducing salt intake. In this study, male and female mice were fed an HSD from 9 to 16 months of age, followed by a normal-salt diet (ND) thereafter until 23 months of age. Controls were continuously fed either ND or HSD. CBF and metabolite profiles were determined longitudinally by arterial spin labeling magnetic resonance imaging and magnetic resonance spectroscopy, respectively. HSD reduced cortical and hippocampal CBF, which recovered after dietary salt normalization, and affected hippocampal but not cortical metabolite profiles. Compared to ND, HSD increased hippocampal glutamine and phosphocreatine levels and decreased creatine and choline levels. Dietary reversal only allowed recovery of glutamine levels. Histology analyses revealed that HSD reduced the dendritic arborization and spine density of cortical and hippocampal neurons, which were not recovered after dietary salt normalization. We conclude that sustained HSD exposure throughout adulthood causes permanent structural and metabolic alterations to the mouse brain that are not fully normalized by lowering dietary salt during aging

    Chitosan oligosaccharide as a plant immune inducer on the Passiflora spp. (passion fruit) CMV disease

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    Cucumber mosaic virus (CMV), one of the main viruses, is responsible for Passiflora spp. (passion fruit) virus diseases, which negatively affect its planting, cultivation, and commercial quality. In this study, a laboratory anti-CMV activity screening model for Passiflora spp. CMV disease was first established. Then, the effects of different antiviral agents of chitosan oligosaccharide (COS), dufulin (DFL), and ningnanmycin (Ning) on CMV virulence rate in Passiflora spp. were determined. The virulence rate and anti-CMV activity in Passiflora spp. treated with COS were 50% and 45.48%, respectively, which were even better than those of DFL (66.67% and 27.30%, respectively) and Ning (83.30% and 9.17%, respectively). Field trials test results showed COS revealed better average control efficiency (47.35%) against Passiflora spp. CMV disease than those of DFL (40.93%) and Ning (33.82%), indicating that COS is effective in the control of the Passiflora spp. CMV disease. Meanwhile, the nutritional quality test results showed that COS could increase the contents of soluble solids, titratable acids, vitamin C, and soluble proteins in Passiflora spp. fruits as well as enhance the polyphenol oxidase (PPO), superoxide dismutase (SOD), and peroxidase (POD) activity in the leaves of Passiflora spp. seedlings. In addition, the combined transcriptome and proteome analysis results showed that COS mainly acted on the Brassinosteroids (BRs) cell signaling pathway, one of plant hormone signal transduction pathway, in Passiflora spp., thus activating the up-regulated expression of TCH4 and CYCD3 genes to improve the resistance to CMV disease. Therefore, our study results demonstrated that COS could be used as a potential plant immune inducer to control the Passiflora spp. CMV disease in the future
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