Translational regulation in mycobacteria and its implications for pathogenicity.

Protein synthesis is a fundamental requirement of all cells for survival and replication. To date, vast numbers of genetic and biochemical studies have been performed to address the mechanisms of translation and its regulation in Escherichia coli, but only a limited number of studies have investigated these processes in other bacteria, particularly in slow growing bacteria like Mycobacterium tuberculosis, the causative agent of human tuberculosis. In this Review, we highlight important differences in the translational machinery of M. tuberculosis compared with E. coli, specifically the presence of two additional proteins and subunit stabilizing elements such as the B9 bridge. We also consider the role of leaderless translation in the ability of M. tuberculosis to establish latent infection and look at the experimental evidence that translational regulatory mechanisms operate in mycobacteria during stress adaptation, particularly focussing on differences in toxin-antitoxin systems between E. coli and M. tuberculosis and on the role of tuneable translational fidelity in conferring phenotypic antibiotic resistance. Finally, we consider the implications of these differences in the context of the biological adaptation of M. tuberculosis and discuss how these regulatory mechanisms could aid in the development of novel therapeutics for tuberculosis

The organisation of fish assemblages in the regulated Lima basin, Northern Portugal

In order to understand the structure of fish assemblages in the modified Lima basin (Northern Portugal), two distinct datasets concerning the presence and abundance of fish species were subjected to multivariate analysis. On the River Lima two types of flow modification are present within kilometres of one another: (a) a reduced and constant flow due to hypolimnetic release; and (b) an intense and irregular flow. A comparison of their influence on fish assemblages revealed a gradient of assemblage types from tributaries to main river sites. The latter were characterised by a strong dominance of cyprinids, particularly Iberian barbel (Barbus bocagei). The former harboured two kinds of fish assemblages: those closer to the river mouth were dominated by the cyprinids Iberian chub (Squalius carolitertii) and Iberian nase (Chondrostoma polylepis), which were also frequently present in the main river; while in those further upstream the predominant species was the brown trout (Salmo trutta). Although explanatory variables such as distance from source, altitude, substrate coarseness and width were the primary correlates of fish assemblage composition, dam construction and flow regulation also had a significant effect upon assemblage structure, particularly by: i) reducing the importance of migratory species; ii) constraining the presence of trout in the regulated segments; and iii) simplifying the community, especially in the case of the constant and reduced flow regimeinfo:eu-repo/semantics/publishedVersio

Combinando habitat y caracterizacion biologica: validacion ecologica del "river habitat survey"

The River Habitat Survey (RHS) is a widespread technique used to characterize the habitats at the fluvial sector level and to quantify the magnitude of physical disturbances. In this study we tested the ability of this method to discriminate sites along a gradient of perturbation and to analyse its relation with typological and environmental features. At the same time, a biological validation of RHS parameters was carried out by crossing the descriptors with three different aquatic communities (benthic macroinvertebrates, fish, and macrophytes). The Portuguese sector of the Douro basin was the area selected for this purposes. Ordination and classification techniques were used to achieve the objectives mentioned, after a reduction of the variables as a function of their relationships and according to their affinity. The multivariate analysis revealed that the variables associated with the river corridor were more appropriate to differentiate the sampling stations along the gradient of disturbance. However, these variables, together with the ones describing the river conditions (together with the RHS derived indices) were strongly dependent on the typological characteristics. This work shows an adequate strategy for the characterization of the fluvial habitat with biological data to obtain an integrated ecological vision

Efeito da Seca e da Invasão pela Esteva (Cistus ladanifer L.) na Capacidade Fotossintética do Sobreiro (Quercus suber L.)

Mestrado em Engenharia Agronómica / Instituto Superior de Agronomia. Universidade de LisboaOs ecossistemas mediterrânicos, de que fazem parte os montados, são hotspots para as alterações climáticas, na medida em que os maiores impactos das alterações climáticas estão previstos para a região mediterrânica, principalmente pelo aumento dos eventos de seca em frequência e intensidade. Estes ecossistemas estão também ameaçados pela invasão por arbustos, o que poderá diminuir, ainda mais, a disponibilidade de água para as árvores e afetar o funcionamento e a resiliência dos ecossistemas. No entanto, os efeitos combinados da seca e da invasão por arbustos nos ecossistemas carecem de investigação. Com o presente trabalho, pretende-se estudar o efeito da seca e a presença da esteva (Cistus ladanifer L.) na capacidade fotossintética do sobreiro (Quercus suber L.) ao longo do ano hidrológico de 2019/2020 num montado Alentejano sujeito a quatro tratamentos: exclusão da chuva/ambiente, invasão/não invasão pela esteva. Foram realizadas curvas de resposta da taxa de assimilação de CO2 à concentração de CO2 intercelular (A/Ci) para estimar os parâmetros da capacidade fotossintética: taxa máxima de carboxilação da RuBisCO (Vcmax) e taxa máxima de transporte de eletrões (Jmax). Foram também medidos cursos diários de potencial hídrico foliar (Y), condutância estomática (gs) e A e determinada a eficiência intrínseca do uso de água em 36 sobreiros e 18 estevas. Os cursos diários de Y, gs e A variaram sazonalmente, com uma forte diminuição no verão, ou seja, após seca prolongada. No sobreiro, o efeito da invasão por esteva sobrepôs-se ao efeito da exclusão da chuva, reduzindo significativamente Y, gs e A. A seca prolongada inibiu severamente a Vcmax e Jmax. As espécies demonstraram tolerância à seca e rápida recuperação após a ocorrência de precipitação, no final do verão. Além das limitações estomáticas, o sobreiro e a esteva também sofreram limitações bioquímicasN/

Small-Extracellular-Vesicle-Derived miRNA Profile Identifies miR-483-3p and miR-326 as Regulators in the Pathogenesis of Antiphospholipid Syndrome (APS)

Antiphospholipid syndrome; Pathogenesis; Small extracellular vesicleSíndrome antifosfolípid; Patogènesi; Petita vesícula extracel·lularSíndrome antifosfolípido; Patogénesis; Pequeña vesícula extracelularPrimary antiphospholipid syndrome (PAPS) is a systemic autoimmune disease associated with recurrent thrombosis and/or obstetric morbidity with persistent antiphospholipid antibodies (aPL). Although these antibodies drive endothelial injury and thrombophilia, the underlying molecular mechanism is still unclear. Small extracellular vesicles (sEVs) contain miRNAs, key players in intercellular communication. To date, the effects of miRNA-derived sEVs in PAPS are not well understood. We characterised the quantity, cellular origin and miRNA profile of sEVs isolated from thrombotic APS patients (PAPS, n = 50), aPL-carrier patients (aPL, n = 30) and healthy donors (HD, n = 30). We found higher circulating sEVs mainly of activated platelet origin in PAPS and aPL patients compared to HD, that were highly engulfed by HUVECs and monocyte. Through miRNA-sequencing analysis, we identified miR-483-3p to be differentially upregulated in sEVs from patients with PAPS and aPL, and miR-326 to be downregulated only in PAPS sEVs. In vitro studies showed that miR-483-3p overexpression in endothelial cells induced an upregulation of the PI3K-AKT pathway that led to endothelial proliferation/dysfunction. MiR-326 downregulation induced NOTCH pathway activation in monocytes with the upregulation of NFKB1, tissue factor and cytokine production. These results provide evidence that miRNA-derived sEVs contribute to APS pathogenesis by producing endothelial cell proliferation, monocyte activation and adhesion/procoagulant factors

Premature termination of transcription is shaped by Rho and translated uORFS in Mycobacterium tuberculosis

Little is known about the decisions behind transcription elongation versus termination in the human pathogen Mycobacterium tuberculosis (M.TB). By applying Term-seq to M.TB we found that the majority of transcription termination is premature and associated with translated regions, i.e., within previously annotated or newly identified open reading frames. Computational predictions and Term-seq analysis, upon depletion of termination factor Rho, suggests that Rho-dependent transcription termination dominates all transcription termination sites (TTS), including those associated with regulatory 5′ leaders. Moreover, our results suggest that tightly coupled translation, in the form of overlapping stop and start codons, may suppress Rho-dependent termination. This study provides detailed insights into novel M.TB cis-regulatory elements, where Rho-dependent, conditional termination of transcription and translational coupling together play major roles in gene expression control. Our findings contribute to a deeper understanding of the fundamental regulatory mechanisms that enable M.TB adaptation to the host environment offering novel potential points of intervention

A Model-Driven Framework for Domain Specific Process Design and Governance

Current BPM approaches and standards have not sufficiently reduced the Business-IT gap. Indeed, today's solutions are mostly domainindependent and platform-dependent, which limits the ability of business matter experts to express business intent and enact process change. In contrast, the tool presented in this paper supports an approach that focuses on BPM and SOA environments in a domain-dependent and platform-independent way. We propose to add a domain specific-layer on top of current solutions so that business stakeholders can design and understand their processes in a more intuitive way. This significantly improves the agility and governance of processes. The demo shows the appropriateness and the feasibility of the approach.Ministerio de Ciencia y Tecnología TIN2015-63502-C3-2-

Modes of action of the current Priority Substances list under the Water Framework Directive and other substances of interest

The Water Framework Directive 2000/60/EC (WFD) has established a strategy for water protection that includes specific measures for pollution control to achieve good chemical and ecological status at European level. There is a need to review the approach to the current listing of priority substances (PS) under the WFD and to the current assessment of the chemical status, and consider eventually a wider range of chemical substances that could be covered in future monitoring programmes. Overall, the aim is to assess the water status more holistically and understand which the real effects are caused by the sum of the chemical substances present in the aquatic environment (including emerging pollutants /other substances of interest, metabolites and transformation products). The assessment of chemical status should be improved and linked with ecological status where relevant. Hundreds of different substances may co-occur, and even if most are present at very small concentrations they could exert a toxic effect on aquatic organisms (Carvalho et al. 2014) exposed for their entire life cycle and indirectly on human health (via food and drinking water consumption). Some of the substances in the current list of Priority Substances and in the first Watch List are considered in groups (e.g. brominated diphenylethers, neonicotinoid insecticides), but the overall approach to chemical pollution is otherwise based on the regulation of single substances. It has become increasingly clear that the risks from the vast number of chemical substances present in the environment cannot be adequately controlled on this basis. The Commission acknowledges the need to consider the potential toxic effects of mixtures of chemicals (EC COM(2012)252, 7th EAP). The challenge is to find a way of capturing a true picture of the chemical status of water bodies based on standards and methods that assess the presence of an adequate range of representative chemical effect types or modes of action (MoA), for example. The knowledge on the MoA is an important driver for linking exposure to chemicals to their effects in the aquatic environment, and therefore for development and application of the scientific methodologies for the assessment of combined effects of chemicals - the effect-based methods (EBM). The EBM, including biomarkers and bioassays, can target different levels of biological organisation in the aquatic environment, such as individual and/or sub-organism, community, and population levels (Carvalho et al. 2014, Ann-Sofie Wernersson et al. 2014). It is however much less clear how these EBM can be used to capture (predictively) the indirect effects that might occur in humans following long-term chronic exposure to pollutants via the aquatic environment. The use of effect-based monitoring approaches, complementary to chemical analysis, could allow assessing chemical status more holistically (rather than with a limited but ever-growing list of individual substances). The use of the EBM offers also the advantage of overcoming analytical difficulties (Kunz et al. 2015) and reducing monitoring costs by screening. To become a credible complement to chemical monitoring information, however, a better understanding of the capabilities and gaps of available EBM is needed. This report, based on a comprehensive literature study, reviews the current PS list and other substances of interest, considering their MoA(s). The review of data from the open sources clearly identified few groups of toxicological endpoints, with the majority driven by non-specific mechanisms (e.g. oxidative stress, activation of metabolizing / detoxifying pathways, histopathology, and others), and few groups with more specific biochemical / physiological pathways (photosynthesis inhibition, acetylcholinesterase inhibition, presence of PAHs metabolites, expression of metallothioneins). The majority of current PS and other substances of interest can be grouped, based on few common toxicological endpoints, and biomarkers are available for determining the concentrations and/or effects of some groups of substances. The identified biomarkers of effect seem to be however in general not very specific. There is clearly no “one size fits all” bioassay / EBM that could provide the toxicological potency of every PS and other substances of interest and their mixture toward all aquatic organisms in all water bodies, but rather a battery of bioassays that should be selected as “fit for purpose”. In addition, the present report allowed identification of uncertainty and inconsistency in observations, and thus identified areas where future investigations can be best directed. The present knowledge about MoA(s) remains limited, especially for the emerging substances of concern, such as pyrethroids and neonicotinoides.JRC.D.2-Water and Marine Resource

Leaf litter decomposition in western Iberian forested wetlands : lentic versus lotic response

Leaf litter breakdown is frequently used to measure both structural and functional integrity in aquatic ecosystems. Forested wetlands are interface systems that received little attention, especially in the Iberian Peninsula. The present study compares the decomposition of alder and willow in two biotopes (lentic and lotic) located in two different sites (Caxarias and Alpiarça). Litterbags were used to compare decomposition among the different treatments. Throughout decay, dry weight loss, nitrogen and phosphorus content, microbial community physiological profiles, microbial and macro-invertebrate colonization were measured at days 2, 4, 8, 16, 32 and 64. Decomposition rates ranged from intermediate to rapid for alder (0.006 day−1 to 0.0338 day−1) and slow to rapid for willow (0.0024 day−1 to 0.0272 day−1), depending on site and biotopes type. The combined effects biotope × time was significant for heterotrophs (P < 0.05), molds (P < 0.05) and yeasts (P < 0.001). The analysis of average well colour development (AWCD), richness (R) and Shannon-Wiener index (H') based on the oxidation of carbon and nitrogen sources by the microbial community, showed differences between the two biotopes, lotic and lentic, and sites. These differences were also shown by the principal component analysis (PCA). Moreover, the macroinvertebrate communities clearly distinguished between lentic and lotic systems. The invertebrates belonging to Plecoptera, Ephemeroptera and Trichoptera were absent from lentic habitats.La descomposición de hojarasca se utiliza frecuentemente para medir la integridad estructural y funcional en los sistemas acuáticos. Los humedales arbolados son sistemas de transición que han recibido escasa atención especialmente en la Península Ibérica. El presente trabajo compara la descomposición de la hojarasca de aliso y sauce en dos sistemas (lenítico y lótico) situados en dos localidades (Caxarias y Alpiarça). Se utilizaron bolsas para hojarasca para comparar la descomposición entre los diferentes tratamientos. Se determinaron las pérdidas de peso seco, contenido en N y P en el detritus vegetal, perfiles fisiológicos de la comunidad microbiana, la colonización microbiana y de macroinvertebrados a los 2, 4, 8, 16, 32 y 64 días del experimento. Las tasas de descomposición variaron de intermedias a rápidas para el aliso (0.006 día−1 a 0.0338 día−1) y de lentas a rápidas para el sauce (0.0024 día−1 a 0.0272 día−1), dependiendo de la localidad de muestreo y del tipo de sistema. Los efectos combinados sistema × tiempo resultaron significativos para los heterótrofos totales (p < 0.05), hongos filamentosos (p < 0.05) y levaduras (p < 0.001). El análisis del desarrollo medio del color (AWCD), la riqueza (R) y el índice de Shannon-Wiener (H') basados en la oxidación de las fuentes de nitrógeno y carbono por parte de la comunidad microbiana, mostraron diferencias entre los dos sistemas, lótico y lenítico y entre las localidades de muestreo. Estas diferencias se pusieron también de manifiesto en el análisis de componentes principales (PCA). Además, las comunidades de macroinvertebrados claramente diferenciaron los sistemas leníticos de los lóticos. Se observó que en los sistemas leníticos los organismos pertenecientes a Plecoptera, Ephemeroptera y Trichoptera estaban ausentes

Supervisão na formação inicial de professores: um modelo em construção

Este estudo surgiu pela necessidade, de enquanto supervisoras da Prática de Ensino Supervisionada II (PES II), refletir sobre o trabalho desenvolvido. Qual o papel da supervisão e avaliação na prática pedagógica, no modelo que preconizamos, com o objetivo de a melhorar, assim como promover a relação entre os interveni - entes: alunos, professores cooperantes e supervisores. Desenvolvemos uma investigação aplicada, inspirada no paradigma crítico cujo objetivo principal do investigador é intervir diretamente numa situação ou contexto e solucionar problemas reais, Investigação Ação (Coutinho et al., 2009). Pretendemos (...) monitorizar os processos centrais da supervisão que são a experi - mentação e a reflexão (Vieira & Moreira, 2011) e, ainda, ir ao encontro das novas tendências da supervisão que se enquadram numa visão democrática, que realça a importância da reflexão e da aprendizagem colaborativa e horizontal, perspetivando o desenvolvimento de mecanismos que possibilitem a auto supervisão e autoapren - dizagem e a capacidade de gerar, gerir e partilhar o conhecimento (...) (Alarcão & Roldão, 2010, citado em Lopes, 2013). Para as alunas o número de horas da PES II era suficiente; cumpriu os objetivos e correspondeu às suas expectativas. A maioria manifestou interesse em estagiar em dois anos de escolaridade, um em cada semestre. Sentiram-se envolvidas na dinâ mica da escola e da sala de aula, tendo sido muito importante a supervisão realizada pela professora cooperante, logo seguida pelo acompanhamento que era feito pelas colegas. Reconheceram o papel fundamental das supervisoras na gestão dos três interve - nientes da supervisão, nomeadamente na preparação, acompanhamento, análise e reflexão da prática pedagógica.info:eu-repo/semantics/publishedVersio