Study of the Cys-His bridge electron transfer pathway in a copper-containing nitrite reductase by site-directed mutagenesis, spectroscopic, and computational methods

The Cys-His bridge as electron transfer conduit in the enzymatic catalysis of nitrite to nitric oxide by nitrite reductase from Sinorhizobium meliloti 2011 (SmNir) was evaluated by site-directed mutagenesis, steady state kinetic studies, UV-vis and EPR spectroscopic measurements as well as computational calculations. The kinetic, structural and spectroscopic properties of the His171Asp (H171D) and Cys172Asp (C172D) SmNir variants were compared with the wild type enzyme. Molecular properties of H171D and C172D indicate that these point mutations have not visible effects on the quaternary structure of SmNir. Both variants are catalytically incompetent using the physiological electron donor pseudoazurin, though C172D presents catalytic activity with the artificial electron donor methyl viologen (kcat =3.9(4) s-1) lower than that of wt SmNir (kcat =240(50) s-1). QM/MM calculations indicate that the lack of activity of H171D may be ascribed to the Nδ1H...OC hydrogen bond that partially shortcuts the T1-T2 bridging Cys-His covalent pathway. The role of the Nδ1H...OC hydrogen bond in the pH-dependent catalytic activity of wt SmNir is also analyzed by monitoring the T1 and T2 oxidation states at the end of the catalytic reaction of wt SmNir at pH6 and 10 by UV-vis and EPR spectroscopies. These data provide insight into how changes in Cys-His bridge interrupts the electron transfer between T1 and T2 and how the pH-dependent catalytic activity of the enzyme are related to pH-dependent structural modifications of the T1-T2 bridging chemical pathway.Fil: Cristaldi, Julio César. Universidad Nacional del Litoral. Facultad de Bioquímica y Ciencias Biológicas. Departamento de Física; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe; ArgentinaFil: Gómez, María C.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe; Argentina. Universidad Nacional del Litoral. Facultad de Bioquímica y Ciencias Biológicas. Departamento de Física; ArgentinaFil: González, Pablo Javier. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe; Argentina. Universidad Nacional del Litoral. Facultad de Bioquímica y Ciencias Biológicas. Departamento de Física; ArgentinaFil: Ferroni, Felix Martín. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe; Argentina. Universidad Nacional del Litoral. Facultad de Bioquímica y Ciencias Biológicas. Departamento de Física; ArgentinaFil: Dalosto, Sergio Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Física del Litoral. Universidad Nacional del Litoral. Instituto de Física del Litoral; ArgentinaFil: Rizzi, Alberto Claudio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe; Argentina. Universidad Nacional del Litoral. Facultad de Bioquímica y Ciencias Biológicas. Departamento de Física; ArgentinaFil: Rivas, Maria Gabriela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe; Argentina. Universidad Nacional del Litoral. Facultad de Bioquímica y Ciencias Biológicas. Departamento de Física; ArgentinaFil: Brondino, Carlos Dante. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe; Argentina. Universidad Nacional del Litoral. Facultad de Bioquímica y Ciencias Biológicas. Departamento de Física; Argentin

Alcohol Use Disorder Treatment: The Association of Pretreatment Use and the Role of Drinking Goal

BACKGROUND: In a recent study conducted in a family medicine setting, the medication acamprosate was found not to be efficacious in the treatment of alcohol dependence, but a drinking goal of abstinence was found to have positive effects on alcohol use outcomes. The purpose of this secondary analysis was to further understand which patients with an alcohol use disorder may be most successfully treated in a primary care setting. METHODS: The study was exploratory and used a trajectory-based approach based on data from the acamprosate treatment trial of 100 participants (recruited mostly by advertisement) who were randomly assigned to receive either acamprosate or a matching placebo. Post hoc trajectories of alcohol use before treatment were identified to examine whether trajectory classes and their interactions with treatment arm (acamprosate or placebo), pretreatment drinking goal (abstinence or a reduction), and time predicted alcohol use outcomes. RESULTS: Three distinct trajectory classes were identified: frequent drinkers, nearly daily drinkers, and consistent daily drinkers. Consistent daily drinkers with a goal of abstinence significantly improved over time on the primary outcome measure of percent days abstinent when compared with frequent and nearly daily drinkers. In addition, all participants with a goal of abstinence, regardless of trajectory class, significantly reduced their percentage of heavy drinking days over time. CONCLUSIONS: Patients with an alcohol use disorder who have a drinking goal of abstinence, in particular consistent daily drinkers, may maximally benefit from alcohol use disorder treatment, including the use of medication, in a primary care setting

The effect of a safety climate training on safety performance. A longitudinal study on the use of individual protective devises

The aim of this study is to explore the effectiveness on safety performance and particularly on the use of individual protective devises at work of a training concerning safety climate. Safety climate and culture research developed successfully in the last decades, showing how safety climate is a robust predictor of safety subjective outcomes, such as safety behaviour, and of objective outcomes, such as accidents and injuries. Literature shows ambiguous findings on the effectiveness of safety training and interventions to improve safety performance of employees and highlights some methodological criticality. The idea of the present study was to test the effect of a training focused on the improvement of safety climate with a longitudinal design. Data collection involved 1495 blue-collars from 6 Italian manufacturing companies. Two different types of safety climate trainings for supervisors were performed and in some cases no training was performed. A long training was scheduled in 6 weekly meetings of 4 hours each and a short one was scheduled in only one meeting of 3 hours. In 3 companies of the sample safety climate and safety performance were measured twice, one before the training and one about 12 months after it. In all the companies monitoring activities on the use of individual protective devises were conducted. The research evidenced that safety climate training does not always help to reduce the number of unsafe behaviours, but a moderation effect of safety climate seems to inflect the relation between training and performance. Particularly, in work-groups with a high safety climate a positive effect of the training always was found

Incorporation of either molybdenum or tungsten into formate dehydrogenase from Desulfovibrio alaskensis NCIMB 13491; EPR assignment of the proximal iron-sulfur cluster to the pterin cofactor in formate dehydrogenases from sulfate-reducing bacteria

J Biol Inorg Chem (2004) 9: 145–151 DOI 10.1007/s00775-003-0506-zWe report the characterization of the molecular properties and EPR studies of a new formate dehydrogenase (FDH) from the sulfate-reducing organism Desulfovibrio alaskensis NCIMB 13491. FDHs are enzymes that catalyze the two-electron oxidation of formate to carbon dioxide in several aerobic and anaerobic organisms. D. alaskensis FDH is a heterodimeric protein with a molecular weight of 126+/-2 kDa composed of two subunits, alpha=93+/-3 kDa and beta=32+/-2 kDa, which contains 6+/-1 Fe/molecule, 0.4+/-0.1 Mo/molecule, 0.3+/-0.1 W/molecule, and 1.3+/-0.1 guanine monophosphate nucleotides. The UV-vis absorption spectrum of D. alaskensis FDH is typical of an iron-sulfur protein with a broad band around 400 nm. Variable-temperature EPR studies performed on reduced samples of D. alaskensis FDH showed the presence of signals associated with the different paramagnetic centers of D. alaskensis FDH. Three rhombic signals having g-values and relaxation behavior characteristic of [4Fe-4S] clusters were observed in the 5-40 K temperature range. Two EPR signals with all the g-values less than two, which accounted for less than 0.1 spin/protein, typical of mononuclear Mo(V) and W(V), respectively, were observed. The signal associated with the W(V) ion has a larger deviation from the free electron g-value, as expected for tungsten in a d(1) configuration, albeit with an unusual relaxation behavior. The EPR parameters of the Mo(V) signal are within the range of values typically found for the slow-type signal observed in several Mo-containing proteins belonging to the xanthine oxidase family of enzymes. Mo(V) resonances are split at temperatures below 50 K by magnetic coupling with one of the Fe/S clusters. The analysis of the inter-center magnetic interaction allowed us to assign the EPR-distinguishable iron-sulfur clusters with those seen in the crystal structure of a homologous enzyme

Impact of coronavirus syndromes on physical and mental health of health care workers: Systematic review and meta-analysis

Background: Health care workers (HCW) are at high risk of developing physical/mental health outcomes related to coronavirus syndromes. Nature and frequency of these outcomes are undetermined. Methods: PRISMA/MOOSE-compliant (PROSPERO-CRD42020180205) systematic review of Web of Science/grey literature until 15th April 2020, to identify studies reporting physical/mental health outcomes in HCW infected/exposed to Severe Acute Respiratory Syndrome -SARS-, Middle East Respiratory Syndrome -MERS-, Novel coronavirus -COVID-19-. Proportion random effect meta-analyses, I2 statistic, quality assessment and sensitivity analysis. Results: 115 articles were included (n=60,458 HCW, age 36.1±7.1, 77.1% female). Physical health outcomes: 75.9% HCW infected by SARS/MERS/COVID-19 reported fever (95%CI=65.9–83.7%, k=12, n=949), 47.9% cough (95%CI=39.2–56.8%, k=14, n=970), 43.6% myalgias (95%CI=31.9–56.0%, k=13, n=898), 42.3% chills (95%CI=20.2–67.9%, k=7, n=716), 41.2% fatigue (95%CI=18.2–68.8%, k=6, n=386), 34.6% headaches (95%CI=23.1–48.2%, k=11, n=893), 31.2% dyspnoea (95%CI=23.2–40.5%, k=12, n=1003), 25.3% sore throat (95%CI=18.8–33.2%, k=8, n=747), 22.2% nausea/vomiting (95%CI=14.9–31.8%, k=6, n=662), 18.8% diarrhoea (95%CI=11.9–28.4%, k=9, n=824). Mental health outcomes: 62.5% HCW exposed to SARS/MERS/COVID-19 reported general health concerns (95%CI=57.0–67,8%, k=2, n=2254), 43.7% fear (95%CI=33.9–54.0%, k=4, n=584), 37.9% insomnia (95%CI=30.9–45.5%, k=6, n=5067), 37.8% psychological distress (95%CI=28.4–48.2%, k=15, n=24,346), 34.4% burnout (95%CI=19.3–53.5%, k=3, n=1337), 29.0% anxiety features (95%CI=14.2–50.3%, k=6, n=9191), 26.3% depressive symptoms (95%CI=12.5–47.1%, k=8, n=9893), 20.7% post-traumatic stress disorder features (95%CI=13.2–31%, k=11, n=3826), 16.1% somatisation (95%CI=0.2–96.0%, k=2, n=2184), 14.0% stigmatisation feelings (95%CI=6.4–28.1%, k=2, n=411). Limitations: Limited amount of evidence for some outcomes and suboptimal design in several studies included. Conclusions: SARS/MERS/COVID-19 have a substantial impact on the physical and mental health of HCW, which should become a priority for public health strategies

Kinetic, Structural, and EPR Studies Reveal That Aldehyde Oxidoreductase from Desulfovibrio gigas Does Not Need a Sulfido Ligand for Catalysis and Give Evidence for a Direct Mo-C Interaction in a Biological System

J. Am. Chem. Soc., 2009, 131 (23), pp 7990–7998 DOI: 10.1021/ja809448rAldehyde oxidoreductase from Desulfovibrio gigas (DgAOR) is a member of the xanthine oxidase(XO) family of mononuclear Mo-enzymes that catalyzes the oxidation of aldehydes to carboxylic acids. The molybdenum site in the enzymes of the XO family shows a distorted square pyramidal geometry in which two ligands, a hydroxyl/water molecule (the catalytic labile site) and a sulfido ligand, have been shown to be essential for catalysis. We report here steady-state kinetic studies of DgAOR with the inhibitors cyanide, ethylene glycol, glycerol, and arsenite, together with crystallographic and EPR studies of the enzyme after reaction with the two alcohols. In contrast to what has been observed in other members of the XO family, cyanide, ethylene glycol, and glycerol are reversible inhibitors of DgAOR. Kinetic data with both cyanide and samples prepared from single crystals confirm that DgAOR does not need a sulfido ligand for catalysis and confirm the absence of this ligand in the coordination sphere of the molybdenum atom in the active enzyme. Addition of ethylene glycol and glycerol to dithionite-reduced DgAOR yields rhombic Mo(V)EPR signals, suggesting that the nearly square pyramidal coordination of the active enzyme is distorted upon alcohol inhibition. This is in agreement with the X-ray structure of the ethylene glycol and glycerolinhibited enzyme, where the catalytically labile OH/OH2 ligand is lost and both alcohols coordinate the Mo site in a η2 fashion. The two adducts present a direct interaction between the molybdenum and one of the carbon atoms of the alcohol moiety, which constitutes the first structural evidence for such a bond in a biological system

Efficacy of IV Immunoglobulins on Psychiatric Symptoms: A Case Report

Borderline personality disorder (BPD) is a fairly common psychiatric illness with a prevalence between 1.8% and 2% in the general population..

Crystal structure and EPR spectra of glycilglycilglycinocopper(II)bromide sesquihydrate

The title compound, Cu(glyglygly)Br·1·5H2O, crystallizes in the space group C2/c, with a = 21.468(7), b = 6.716(5), c = 16.166(6) A, β = 98.39°, and Z = 8. The tripeptide is bonded to one Cu(II) ion through the nitrogen [Cu–N=1.97(1)A] and oxygen [Cu–O=2.019(8)A] atoms of the amino end glycine residue and to another Cu(II) through one oxygen atom [Cu–O=1.931(9)A] of the terminal carboxyl group. This give rise to covalently bonded and infinite ···–Cu–tripeptide–Cu–··· chains. These chains are linked to one another by a network of H-bonds involving the water molecules and bromide ions. The Cu(II) ion is in a distorted tetragonal pyramidal coordination polyhedron. At the corner of the base of the pyramid are the terminal glycine nitrogen and oxygen atoms of one tripeptide, a carboxylic oxygen of another tripeptide and a bromide ion. The fivefold coordination is completed with a water molecule at the top of the pyramid [Cu–Ow=2.286(9)A]. For all orientations of the applied magnetic field the single crystal EPR spectra display a single anisotropic exchange collapsed resonance without hyperfine structure. Its position was measured in three perpendicular planes and the crystal g-tensor evaluated from the data. This tensor is interpreted in terms of the contributing Cu(II) complexes in the unit cell to deduce the principal values g1 = 2.273, g2 = 2.050 and g3 = 2.131 for the molecular gyromagnetic tensor. We also discuss the magnitude of the exchange interaction between neighboring copper ions in the lattice on the basis of the features in the EPR spectra and the structural information.Facultad de Ciencias Exacta

DESTRESS: Um jogo para treinar competências de gestão de stress relacionado com o uso da tecnologia

A saúde e a segurança no local de trabalho fazem parte das políticas de âmbito social e de emprego da União Europeia, sob os Princípios e Direitos Fundamentais no Trabalho. No entanto, apesar de existir um vasto investimento na prevenção de riscos, ainda há grandes desafios no que diz respeito aos riscos psicossociais e ao stress no trabalho. O impacto negativo dos riscos psicossociais e do stress no bem-estar e na produtividade representa um custo para muitas organizações, mas especialmente para as pequenas e médias empresas (PMEs). O projeto “Desenvolver competências de resiliência face ao stress @PMEs” (DeSTRESS) pretende desenvolver uma formação inovadora para responder a este problema. Baseando-se no estado da arte da investigação científica, está a ser desenvolvida uma formação com base num jogo inovador e utilizando uma plataforma digital. Este jogo está a ser desenvolvido usando as técnicas mais recentes de gamificação e formação baseada em jogos, complementadas por um conjunto de ferramentas e recursos práticos que facilitarão a transferência do conhecimento para o local de trabalho.info:eu-repo/semantics/publishedVersio