Towards a structural understanding of the fibrillization pathway in Machado-Joseph’s disease: trapping early oligomers of non-expanded ataxin-3

Machado-Joseph’s disease is caused by a CAG trinucleotide repeat expansion that is translated into an abnormally long polyglutamine tract in the protein ataxin-3. Except for the polyglutamine region, proteins associated with polyglutamine diseases are unrelated, and for all of these diseases aggregates containing these proteins are the major components of the nuclear proteinaceous deposits found in the brain. Aggregates of the expanded proteins display amyloid-like morphological and biophysical properties. Human ataxin-3 containing a non-pathological number of glutamine residues (14Q), as well as its Caenorhabditis elegans (1Q) orthologue, showed a high tendency towards self-interaction and aggregation, under nearphysiological conditions. In order to understand the discrete steps in the assembly process leading to ataxin-3 oligomerization, we have separated chromatographically high molecular mass oligomers as well as medium mass multimers of non-expanded ataxin-3. We show that: (a) oligomerization occurs independently of the poly(Q)-repeat and it is accompanied by an increase in b-structure; and (b) the first intermediate in the oligomerization pathway is a Josephin domain-mediated dimer of ataxin- 3. Furthermore, non-expanded ataxin-3 oligomers are recognized by a specific antibody that targets a conformational epitope present in soluble cytotoxic species found in the fibrillization pathway of expanded polyglutamine proteins and other amyloid-forming proteins. Imaging of the oligomeric forms of the non-pathological protein using electron microscopy reveals globular particles, as well as short chains of such particles that likely mimic the initial stages in the fibrillogenesis pathway occurring in the polyglutamine-expanded protein. Thus, they constitute potential targets for therapeutic approaches in Machado-Joseph’s disease, as well as valuable diagnostic markers in disease settings

Azithromycin Treatment Alters Gene Expression in Inflammatory, Lipid Metabolism, and Cell Cycle Pathways in Well-Differentiated Human Airway Epithelia

Prolonged macrolide antibiotic therapy at low doses improves clinical outcome in patients affected with diffuse panbronchiolitis and cystic fibrosis. Consensus is building that the therapeutic effects are due to anti-inflammatory, rather than anti-microbial activities, but the mode of action is likely complex. To gain insights into how the macrolide azithromycin (AZT) modulates inflammatory responses in airways, well-differentiated primary cultures of human airway epithelia were exposed to AZT alone, an inflammatory stimulus consisting of soluble factors from cystic fibrosis airways, or AZT followed by the inflammatory stimulus. RNA microarrays were conducted to identify global and specific gene expression changes. Analysis of gene expression changes revealed that the AZT treatment alone altered the gene profile of the cells, primarily by significantly increasing the expression of lipid/cholesterol genes and decreasing the expression of cell cycle/mitosis genes. The increase in cholesterol biosynthetic genes was confirmed by increased filipin staining, an index of free cholesterol, after AZT treatment. AZT also affected genes with inflammatory annotations, but the effect was variable (both up- and down-regulation) and gene specific. AZT pretreatment prevented the up-regulation of some genes, such as MUC5AC and MMP9, triggered by the inflammatory stimulus, but the up-regulation of other inflammatory genes, e.g., cytokines and chemokines, such as interleukin-8, was not affected. On the other hand, HLA genes were increased by AZT. Notably, secreted IL-8 protein levels did not reflect mRNA levels, and were, in fact, higher after AZT pretreatment in cultures exposed to the inflammatory stimulus, suggesting that AZT can affect inflammatory pathways other than by altering gene expression. These findings suggest that the specific effects of AZT on inflamed and non-inflamed airway epithelia are likely relevant to its clinical activity, and their apparent complexity may help explain the diverse immunomodulatory roles of macrolides

Different exercise protocols improve metabolic syndrome markers, tissue triglycerides content and antioxidant status in rats

Background: An increase in the prevalence of obesity entails great expenditure for governments. Physical exercise is a powerful tool in the combat against obesity and obesity-associated diseases. This study sought to determine the effect of three different exercise protocols on metabolic syndrome and lipid peroxidation markers and the activity of antioxidant enzymes in adult Wistar rats (120 days old).Methods: Animals were randomly divided into four groups: the control (C) group was kept sedentary throughout the study; the aerobic group (A) swam1 h per day, 5 days per week, at 80% lactate threshold intensity; the strength group (S) performed strength training with four series of 10 jumps, 5 days per week; and the Concurrent group (AS) was trained using the aerobic protocol three days per week and the strength protocol two days per week.Results: Groups A and S exhibited a reduction in body weight compared to group C. All exercised animals showed a reduction in triglyceride concentrations in fatty tissues and the liver. Exercised animals also exhibited a reduction in lipid peroxidation markers (TBARS) and an increase in serum superoxide dismutase activity. Animals in group A had increased levels of liver catalase and superoxide dismutase activities.Conclusions: We concluded that all physical activity protocols improved the antioxidant systems of the animals and decreased the storage of triglycerides in the investigated tissues

Co-cultivation of Thermoanaerobacter strains with a methanogenic partner enhances glycerol conversion

Glycerolrich waste streams produced by the biodiesel, bioethanol and oleochemical industries can be treated and valorized by anaerobic microbial communities to produce methane. As current knowledge of the microorganisms involved in thermophilic glycerol conversion to methane is scarce, thermophilic glyceroldegrading methanogenic communities were enriched. A coculture of Thermoanaerobacter and Methanothermobacter species was obtained, pointing to a nonobligately syntrophic glycerol degradation. This hypothesis was further studied by incubating Thermoanaerobacter brockii subsp. finnii and T. wiegelii with glycerol (10 mM) in pure culture and with different hydrogenotrophic methanogens. The presence of the methanogen accelerated glycerol fermentation by the two Thermoanaerobacter strains up to 3.3 mM day1, corresponding to 12 times higher volumetric glycerol depletion rates in the methanogenic cocultures than in the pure bacterial cultures. The catabolic pathways of glycerol conversion were identified by genome analysis of the two Thermoanaerobacter strains. NADH and reduced ferredoxin formed in the pathway are linked to proton reduction, which becomes thermodynamically favourable when the hydrogen partial pressure is kept low by the hydrogenotrophic methanogenic partner.The authors thank Ruben Gonçalves for preparing the thermophilic biomass and Andreia Salvador for the sup port with the microbial communities’ analysis. This study was supported by the Portuguese Foundation for Science and Technology (FCT) under the scope of the strategic funding of UID/BIO/04469/2019 unit, Project SAICTPAC/0040/2015 (POCI-01-0145-FEDER-016403) and BioTecNorte operation (NORTE-01-0145-FEDER 000004) funded by the European Regional Development Fund under the scope of Norte2020 – Programa Opera cional Regional do Norte. The authors also acknowledge the financial support of FCT and European Social Fund through the grants attributed to C.P. Magalhaes (SFRH/BD/132845/2017) and A.L. Arantes (PD/BD/128030/2016).info:eu-repo/semantics/publishedVersio

Enhanced glycerol conversion by Thermoanaerobacter strains

Glycerol-rich waste streams produced as a surplus by the biodiesel industry can be treated and valorized by anaerobic microbial communities to produce biogas. Glycerol is a highly reduced compound. Its complete degradation to methane and carbon dioxide requires a syntrophic cooperation of anaerobic bacteria and archaea, either directly or through propionate, lactate or ethanol as intermediates. The aim of this work was to study glycerol valorization to methane by thermophilic microbial communities. Glycerol-degrading methanogenic communities were enriched at 55 ºC. A co-culture of Thermoanaerobacter and Methanothermobacter was obtained pointing to facultatively syntrophic glycerol degradation. This hypothesis was further tested by incubating Thermoanaerobacter brockii subsp. finnii and T. wiegelli type strains with glycerol (10 mmol L-1) in pure culture and with different hydrogenotrophic methanogens. The presence of the methanogen accelerated glycerol fermentation by the two Thermoanaerobacter strains up to 3.3 mmol L-1 day-1, corresponding to 12 times higher volumetric glycerol depletion rates in the methanogenic co-cultures than in pure bacterial cultures. The methanogen acted as a biological electron acceptor, which enhanced glycerol conversion by Thermoanaerobacter species, since it facilitates the redox balance and contributes to a higher energy gain of these bacteria. Therefore, syntrophic glycerol fermentation promotes faster anaerobic treatment of glycerol rich waste streams coupled to methane production.info:eu-repo/semantics/publishedVersio

Desemprego: experiências de transição

Work appears as an important determinant in psychological health and well-being (Blustein, 2008). However, the current structure of the labor market is complex, unpredictable and unstable, making it necessary to rethink the meaning of work in human existence. This article focuses on the different types of transitions (voluntary vs. involuntary) as well on the different reactions to unemployment, and presents some intervention strategies in the context of career counseling, conceived as a (possible) response to changes in employment.Le travail apparaît comme un déterminant de la santé psychologique et du bien-être (Blustein, 2008). Cependant, la structure actuelle du marché du travail est complexe, imprévisible et instable, ce qui rend nécessaire de repenser la signification du travail dans l’existence humaine. Cet article se concentre en la première partie sur les différents types de transition (volontaire ou involontaire), et la diversité des modes de réaction au chômage, et la seconde partie présente quelques stratégies d’intervention dans le contexte de l’orientation professionnelle, conçue comme une réponse (possible) à des changements dans l’emploi.O trabalho afigura-se como determinante para a saúde psicológica e o bem-estar (Blustein, 2008). Contudo, a actual estrutura do mercado de trabalho é complexa, imprevisível e instável, sendo necessário repensar o significado do trabalho na existência humana. O presente artigo incide, na primeira parte sobre os diferentes tipos de transição (voluntária vs. involuntária), e a diversidade de modos de reacção face ao desemprego, e na segunda parte, são apresentadas algumas estratégias de intervenção, no âmbito do aconselhamento de carreira, concebidas como uma (possível) resposta às mudanças que ocorrem ao nível do emprego

description of the methodological approach

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HBM4EU chromates study: determinants of exposure to hexavalent chromium in plating, welding and other occupational settings

Work-related exposures in industrial processing of chromate (chrome plating, surface treatment, and welding) raise concerns regarding the health risk of hexavalent chromium (Cr(VI)). In this study, performed under the HBM4EU project, we focused on better understanding the determinants of exposure and recognising how risk management measures (RMMs) contribute to a reduction in exposure. HBM and occupational hygiene data were collected from 399 workers and 203 controls recruited in nine European countries. Urinary total chromium (U-Cr), personal inhalable and respirable dust of Cr and Cr(VI), and Cr from hand wipes were collected. Data on the RMMs were collected by questionnaires. We studied the association between different exposure parameters and the use of RMMs. The relationship between exposure by inhalation and U-Cr in different worker groups was analysed using regression analysis and found a strong association. Automatisation of Cr electroplating dipping explained lower exposure levels in platers. The use of personal protective equipment resulted in lower U-Cr levels in welding, bath plating, and painting. An effect of wearing gloves was observed in machining. An effect of local exhaust ventilation and training was observed in welding. Regression analyses showed that in platers, exposure to an air level of 5 µg/m3 corresponds to a U-Cr level of 7 µg/g of creatinine. In welders, the same inhalation exposure resulted in lower U-Cr levels reflecting toxicokinetic differences of different chromium species.info:eu-repo/semantics/publishedVersio

Expressed sequence tag analysis of the human pathogen Paracoccidioides brasiliensis yeast phase: Identification of putative homologues of Candida albicans virulence and pathogenicity genes

Paracoccidioides brasiliensis, a thermodimorphic fungus, is the causative agent of the prevalent systemic mycosis in Latin America, paracoccidioidomycosis. We present here a survey of expressed genes in the yeast pathogenic phase of P. brasiliensis. We obtained 13,490 expressed sequence tags from both 5' and 3' ends. Clustering analysis yielded the partial sequences of 4,692 expressed genes that were functionally classified by similarity to known genes. We have identified several Candida albicans virulence and pathogenicity homologues in P. brasiliensis. Furthermore, we have analyzed the expression of some of these genes during the dimorphic yeast-mycelium-yeast transition by real-time quantitative reverse transcription-PCR. Clustering analysis of the mycelium-yeast transition revealed three groups: (i) RBT, hydrophobin, and isocitrate lyase; (ii) malate dehydrogenase, contigs Pb1067 and Pb1145, GPI, and alternative oxidase; and (iii) ubiquitin, delta-9-desaturase, HSP70, HSP82, and HSP104. the first two groups displayed high mRNA expression in the mycelial phase, whereas the third group showed higher mRNA expression in the yeast phase. Our results suggest the possible conservation of pathogenicity and virulence mechanisms among fungi, expand considerably gene identification in P. brasiliensis, and provide a broader basis for further progress in understanding its biological peculiarities.Univ São Paulo, Dept Ciencias Farmaceut, Fac Ciencias Farmaceut Ribeirao Preto, BR-14040903 Ribeirao Preto, SP, BrazilUniv São Paulo, Fac Filosofia Ciencias & Letras Ribeirao Pret, BR-14040903 Ribeirao Preto, SP, BrazilInst Pasteur, Unite Genet Mol Levures, Paris, FranceUniv Vale do Paraiba, UNIVAP, Vale Do Paraiba, BrazilUniv Mogi das Cruzes, Nucleo Integrado Biotecnol, Mogi Das Cruzes, BrazilUniversidade Federal de São Paulo, Dept Microbiol Imunol & Parasitol, São Paulo, BrazilUniversidade Federal de São Paulo, Dept Microbiol Imunol & Parasitol, São Paulo, BrazilWeb of Scienc