•Sulfated polysaccharide (SFP) possess a high sulfate content.•The main constituent of the SFP is iota-carrageenan.•SFP reduced the oxidative stress and the gastric damage in vivo.•SFP also revealed ...the relevant antioxidant activity in vitro.
A sulfated polysaccharide (SFP) fraction from the marine alga Solieria filiformis was extracted and submitted to microanalysis, molar mass estimation and spectroscopic analysis. We evaluated its gastroprotective potential in vivo in an ethanol-induced gastric damage model and its in vitro antioxidant properties (DPPH, chelating ferrous ability and total antioxidant capacity). Its chemical composition revealed to be essentially an iota-carrageenan with a molar mass of 210.9kDa and high degree of substitution for sulfate groups (1.08). In vivo, SFP significantly (P<0.05) reduced, in a dose dependent manner, the ethanol-induced gastric damage. SFP prevents glutathione consume and increase of malondialdehyde and hemoglobin levels. SFP presented an IC50 of 1.77mg/mL in scavenging DPPH. The chelating ferrous ability was 38.98%, and the total antioxidant capacity was 2.01mg/mL. Thus, SFP prevents the development of ethanol-induced gastric damage by reducing oxidative stress in vivo and possesses relevant antioxidant activity in vitro.
The present work aimed at carrying out the isolation and biochemical characterization of a sulfated polysaccharide fraction (PLS) from the marine algae Gracilaria intermedia and investigating its ...anti-inflammatory and antinociceptive potential. PLS was obtained through enzymatic digestion with papain and analyzed by means of gel permeation chromatography and Nuclear Magnetic Resonance to 1H and 13C. In order to evaluate the potential of anti-inflammatory action of PLS, we performed paw edema induced by carrageenan, dextran, compound 48/80, histamine and serotonin. In addition, we also measured the concentration of myeloperoxidase, cytokines, the count of inflammatory cells and performed tests of the nociception. The PLS isolated was of high purity and free of contaminants such as proteins, and had molecular weight of 410 kDa. The same macromolecule was able to decrease the paw edema induced by all inflammatory agents (P < 0.05), myeloperoxidase (MPO) activity, neutrophil migration and IL-1β levels. It also decreased acetic acid-induced writhing (P < 0.05) and formalin-induced paw licking time (P < 0.05), but no in hot plate test. In summary, the PLS decreased the inflammatory response by reducing neutrophil migration and modulating IL-1β production and antinociceptive effects by a peripheral mechanism dependent on the down-modulation of the inflammatory mediators.
The active sites of the xanthine oxidase and sulfite oxidase enzyme families contain one pterin−dithiolene cofactor ligand bound to a molybdenum atom. Consequently, monodithiolene molybdenum ...complexes have been sought by exploratory synthesis for structural and reactivity studies. Reaction of MoO(S2C2Me2)21- or MoO(bdt)21- with PhSeCl results in removal of one dithiolate ligand and formation of MoOCl2(S2C2Me2)1- (1) or MoOCl2(bdt)1- (2), which undergoes ligand substitution reactions to form other monodithiolene complexes MoO(2-AdS)2(S2C2Me2)1- (3), MoO(SR)2(bdt)1- (R = 2-Ad (4), 2,4,6-Pr i 3C6H2 (5)), and MoOCl(SC6H2-2,4,6-Pr i 3)(bdt)1- (6) (Ad = 2-adamantyl, bdt = benzene-1,2-dithiolate). These complexes have square pyramidal structures with apical oxo ligands, exhibit rhombic EPR spectra, and 3−5 are electrochemically reducible to MoIVO species. Complexes 1−6 constitute the first examples of five-coordinate monodithiolene MoVO complexes; 6 approaches the proposed structure of the high-pH form of sulfite oxidase. Treatment of MoO2(OSiPh3)2 with Li2(bdt) in THF affords MoO2(OSiPh3)(bdt)1- (8). Reaction of 8 with 2,4,6-Pr i 3C6H2SH in acetonitrile gives MoO2(SC6H2-2,4,6-Pr i 3)(bdt)1- (9, 55%). Complexes 8 and 9 are square pyramidal with apical and basal oxo ligands. With one dithiolene and one thiolate ligand of a square pyramidal MoVIO2S3 coordination unit, 9 closely resembles the oxidized sites in sulfite oxidase and assimilatory nitrate reductase as deduced from crystallography (sulfite oxidase) and Mo EXAFS. The complex is the first structural analogue of the active sites in fully oxidized members of the sulfite oxidase family. This work provides a starting point for the development of both structural and reactivity analogues of members of this family.
The prognosis for malignant gliomas remains poor, and new treatments are urgently needed. Targeted suicide gene therapy exploits the enzymatic conversion of a prodrug, such as a nucleoside analog, ...into a cytotoxic compound. Although this therapeutic strategy has been considered a promising regimen for central nervous system (CNS) tumors, several obstacles have been encountered such as inefficient gene transfer to the tumor cells, limited prodrug penetration into the CNS, and inefficient enzymatic activity of the suicide gene. We report here the cloning and successful application of a novel thymidine kinase 1 (TK1) from the tomato plant, with favorable characteristics in vitro and in vivo. This enzyme (toTK1) is highly specific for the nucleoside analog prodrug zidovudine (azidothymidine, AZT), which is known to penetrate the blood-brain barrier. An important feature of toTK1 is that it efficiently phosphorylates its substrate AZT not only to AZT monophosphate, but also to AZT diphosphate, with excellent kinetics. The efficiency of the toTK1/AZT system was confirmed when toTK1-transduced human glioblastoma (GBM) cells displayed a 500-fold increased sensitivity to AZT compared with wild-type cells. In addition, when neural progenitor cells were used as delivery vectors for toTK1 in intracranial GBM xenografts in nude rats, substantial attenuation of tumor growth was achieved in animals exposed to AZT, and survival of the animals was significantly improved compared with controls. The novel toTK1/AZT suicide gene therapy system in combination with stem cell-mediated gene delivery promises new treatment of malignant gliomas.
Hydrogen storage and transportation in form of charged Liquid Organic Hydrogen Carrier (LOHC) systems is attractive as these hydrocarbon-based carrier molecules can provide hydrogen using the ...existing infrastructure for fossil fuels. For hydrogen release on board of heavy-duty vehicles, however, the limited volumetric power density of the hydrogen release units was so far seen as a critical factor. Herein, we show that the power density achieved in perhydro benzyltoluene dehydrogenation in a classical fixed-bed dehydrogenation reactor can be doubled by applying an inverted multi-tubular reactor with upstream LOHC flow and hydrogen release in the reactor housing and crossflow heating through perpendicular heating tubes. The resulting power densities of up to 0.76kWH2-LHV L−1reactor-outside (with respect to the total reactor housing), and 2.34kWH2-LHV L−1reactor-inside (with respect to inner reactor volume) bring on-board hydrogen release of LOHC-bound hydrogen much closer to technical reality. This very impressive increase in power density is mainly due to the fact, that the inverted arrangement of catalyst bed and heat transfer tubes offers a much higher catalyst volume per reactor volume compared to a classical fixed-bed reactor.
•Design of a new reactor concept for the dehydrogenation of perhydro benzyltoluene.•Doubling the release unit's power density by inversion of a multi-tubular reactor.•Description of the reactor's dependency on temperature, pressure and LOHC flow rate.•Estimation of heat transfer coefficients for a dehydrogenation reactor.
•Funding decisions can benefit from multi-attribute utility theory.•Value Focused Thinking can reinforce the strategic alignment of funding programs.•We suggest that agency personnel should be in the ...role of decision-makers.•We suggest that attributes of value functions should be based on factual information.•Factual assessments provided by reviewers serve as data for program evaluation.
Research funding programs are a policy instrument utilized by governments to influence the innovation process. They are usually elaborated, launched and managed by research funding agencies. In order to select the most adequate research projects, agencies often rely on the peer review process.
This paper introduces a methodology to support funding decisions based on the peer review process. The methodology involves the use of a multicriteria decision model to support the assessment, evaluation, prioritization and selection of applications, under a multi-step decision-making process, which fits into a strategic management cycle within the agency. The Multiattribute Value Theory, being considered under a Value Focused Thinking approach, provides a basis for the construction of the multicriteria decision model. The good practices in peer review and also a logical framework for program management are considered by the methodology.
A pilot study, presented in the paper, involved a retrospective implementation of a peer review process in the context of a program launched by the Ministry for Science, Technology, Innovations and Communications and the National Council of Technological and Scientific Development, in Brazil. The methodology allowed a clear distinction of roles. The agency staff in the role of decision-makers was responsible for making value judgments on behalf of the agency. The experts, in the role of committee members and ad hoc reviewers, contributed with their expertise by providing objective assessments. Such assessments served as a basis for evaluating the applications, characterizing the possible portfolios, and can be considered as data in future program evaluation studies.
Programmed cell death (PCD) is a genetically controlled cell death that is regulated during development and activated in response to environmental stresses or pathogen infection. The degree of ...conservation of PCD across kingdoms and phylum is not yet clear; however, whereas caspases are proteases that act as key components of animal apoptosis, plants have no orthologous caspase sequences in their genomes. The discovery of plant and fungi metacaspases as proteases most closely related to animal caspases led to the hypothesis that metacaspases are the functional homologues of animal caspases in these organisms. Arabidopsis thaliana has nine metacaspase genes, and so far it is unknown which members of the family if any are involved in the regulation of PCD. We show here that metacaspase-8 (AtMC8) is a member of the gene family strongly up-regulated by oxidative stresses caused by UVC, H2O2, or methyl viologen. This up-regulation was dependent of RCD1, a mediator of the oxidative stress response. Recombinant metacaspase-8 cleaved after arginine, had a pH optimum of 8, and complemented the H2O2 no-death phenotype of a yeast metacaspase knock-out. Overexpressing AtMC8 up-regulated PCD induced by UVC or H2O2, and knocking out AtMC8 reduced cell death triggered by UVC and H2O2 in protoplasts. Knock-out seeds and seedlings had an increased tolerance to the herbicide methyl viologen. We suggest that metacaspase-8 is part of an evolutionary conserved PCD pathway activated by oxidative stress.
Brain aging is a naturally occurring process resulting in the decline of cognitive functions and increased vulnerability to develop age‐associated disorders. Fluctuation in lipid species is crucial ...for normal brain development and function. However, impaired lipid metabolism and changes in lipid composition in the brain have been increasingly recognized to play a crucial role in physiological aging, as well as in several neurodegenerative diseases. In the last decades, the role of sexual dimorphism in the vulnerability to develop age‐related neurodegeneration has increased. However, further studies are warranted for detailed assessment of how age, sex, and additional non‐biological factors may influence the lipid changes in brains. The aim of this work is to address the presence of sex differences in the brain lipid changes that occur along aging, and in the two most common age‐related neurodegenerative disorders (Alzheimer's and Parkinson's diseases). We included the studies that assessed lipid‐related alterations in the brain of both humans and experimental models. Additionally, we explored the influence of sex on lipid‐lowering therapies. We conclude that sex exerts a notable effect on lipid modifications occurring with age and neurodegeneration, and in lipid‐reducing interventions. Therefore, the application of sex as an experimental variable is strongly encouraged for future research in the field of precision medicine approach.
Modifications in the lipid profile across the lifespan are crucial for brain development and functions. Aging is associated with both physiological and pathological changes in lipid species and metabolism, and different factors play a role in them. In this review, we provide evidence of sex‐specific lipid changes along aging, Alzheimer's and Parkinson's diseases, as well as in the response to lipid‐lowering therapies. Therefore, research would benefit from acknowledging sex differences in physiology and pathology, in order to provide more accurate diagnostic tools and therapeutical strategies.
Background: The yeast CDC9 gene encodes a DNA ligase I activity required during nuclear DNA replication to ligate the Okazaki fragments formed when the lagging DNA strand is synthesised. The only ...other DNA ligase predicted from the yeast genome sequence, DNL4/LIG4, is specifically involved in a non-homologous DNA end-joining reaction. What then is the source of the DNA ligase activity required for replication of the yeast mitochondrial genome?
Results: We report that CDC9 encodes two distinct polypeptides expressed from consecutive in-frame AUG codons. Translational initiation at these two sites gives rise to polypeptides differing by a 23 residue amino-terminal extension, which corresponds to a functional mitochondrial pre-sequence sufficient to direct import into yeast mitochondria. Initiation at the first AUG codon results in a 755 amino-acid polypeptide that is imported into mitochondria, whereupon the pre-sequence is proteolytically removed to yield the mature mitochondrial form of Cdc9p. Initiation at the second AUG codon produces a 732 amino-acid polypeptide, which is localised to the nucleus. Cells expressing only the nuclear isoform were found to be specifically defective in the maintenance of the mitochondrial genome.
Conclusions:CDC9 encodes two distinct forms of DNA ligase I. The first is targeted to the mitochondrion and is required for propagation and maintenance of mitochondrial DNA, the second localises to the nucleus and is sufficient for the essential cell-division function associated with this gene.
Transduced deoxyribonucleoside kinases (dNK) can be used to kill recipient cells in combination with nucleoside prodrugs. The Drosophila melanogaster multisubstrate dNK (Dm-dNK) displays a superior ...turnover rate and has a great plasticity regarding its substrates. We used directed evolution to create Dm-dNK mutants with increased specificity for several nucleoside analogs (NAs) used as anticancer or antiviral drugs. Four mutants were characterized for the ability to sensitize Escherichia coli toward analogs and for their substrate specificity and kinetic parameters. The mutants had a reduced ability to phosphorylate pyrimidines, while the ability to phosphorylate purine analogs was relatively similar to the wild-type enzyme. We selected two mutants, for expression in the osteosarcoma 143B, the glioblastoma U-87M-G and the breast cancer MCF7 cell lines. The sensitivities of the transduced cell lines in the presence of the NAs fludarabine (F-AraA), cladribine (CdA), vidarabine and cytarabine were compared to the parental cell lines. The sensitivity of 143B cells was increased by 470-fold in the presence of CdA and of U-87M-G cells by 435-fold in the presence of F-AraA. We also show that a choice of the selection and screening system plays a crucial role when optimizing suicide genes by directed evolution.
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