Yellow fever virus (YFV) is a member of the Flaviviridae family. In Brazil, yellow fever (YF) cases have increased dramatically in sylvatic areas neighboring urban zones in the last few years. ...Because of the high lethality rates associated with infection and absence of any antiviral treatments, it is essential to identify therapeutic options to respond to YFV outbreaks. Repurposing of clinically approved drugs represents the fastest alternative to discover antivirals for public health emergencies. Other Flaviviruses, such as Zika (ZIKV) and dengue (DENV) viruses, are susceptible to sofosbuvir, a clinically approved drug against hepatitis C virus (HCV). Our data showed that sofosbuvir docks onto YFV RNA polymerase using conserved amino acid residues for nucleotide binding. This drug inhibited the replication of both vaccine and wild-type strains of YFV on human hepatoma cells, with EC50 values around 5 μM. Sofosbuvir protected YFV-infected neonatal Swiss mice and adult type I interferon receptor knockout mice (A129-/-) from mortality and weight loss. Because of its safety profile in humans and significant antiviral effects in vitro and in mice, Sofosbuvir may represent a novel therapeutic option for the treatment of YF. Key-words: Yellow fever virus; Yellow fever, antiviral; sofosbuvir.
Resumo: O Programa Nacional de Imunizações (PNI), coordenado pelo Ministério da Saúde, de forma compartilhada com as secretarias estaduais e municipais de saúde, vem se consolidando como uma das ...principais e mais relevantes intervenções em saúde pública, com a conquista de resultados importantes, como a certificação de área livre da circulação do poliovírus selvagem, a eliminação da circulação do vírus da rubéola e pelo importante impacto na redução dos casos e mortes pelas doenças imunopreveníveis, a partir da sua criação em 1973. O Brasil é um dos países que oferece o maior número de vacinas, de forma gratuita, com 15 vacinas para crianças, 9 para os adolescentes, cinco para os adultos e idosos. A partir dessa expansão do programa e da manutenção de elevadas coberturas vacinais, foi possível observar o rápido impacto na diminuição das doenças imunopreveníveis, mudando completamente o cenário epidemiológico dessas doenças no país, ao longo destas últimas quatro décadas. Atualmente, o país vive um contexto em que aumenta a parcela da população sem vacinação adequada. Na medida em que as doenças passam a não circular mais, justamente porque se mantiveram elevadas coberturas vacinais principalmente a partir dos anos 2000, muitas doenças tornaram-se desconhecidas, fazendo com que algumas pessoas não tenham noção do perigo representado por elas. É necessário, portanto, entender os múltiplos fatores que estão contribuindo para essa diminuição, criando, dessa forma, o risco de ressurgimento de doenças graves já controladas ou eliminadas na população.
Resumen: El Programa Nacional de Inmunizaciones de Brasil (PNI), coordinado por el Ministerio de la Salud, de forma compartida con Las secretarías estatales y municipales de salud, se ha consolidando como una de las principales y más relevantes intervenciones en salud pública, con la conquista de resultados importantes, como la certificación de área libre de la circulación del poliovirus salvaje, la eliminación de la circulación del virus de la rubeola, además de por el importante impacto en la reducción de los casos y muertes por enfermedades inmunoprevenibles, a partir de su creación en 1973. Brasil es uno de los países que ofrece el mayor número de vacunas, de forma gratuita, con 15 vacunas, 9 para adolescentes, 5 para adultos y ancianos. A partir de esta expansión del programa y del mantenimiento de elevadas coberturas de vacunación fue posible observar el rápido impacto en la disminución de las enfermedades inmunoprevenibles, cambiando completamente el escenario epidemiológico de esas enfermedades en el país, a lo largo de estas últimas cuatro décadas. Actualmente, el país vive un contexto en que aumenta la proporción de la población sin vacunación adecuada. A medida que las enfermedades pasan a no circular más, justamente porque se mantuvieron elevadas, principalmente a partir de la década del 2000, muchas enfermedades se convirtieron en desconocidas, provocando que algunas personas no tengan noción del peligro representado por ellas. Es necesario, por tanto, entender los múltiples factores que están contribuyendo a esta disminución, creando, de esta forma, el riesgo de resurgimiento de enfermedades graves ya controladas o eliminadas de la población.
Abstract: The Brazilian National Immunization Program (PNI, in Portuguese) is coordinated by the Ministry of Health in cooperation with state and municipal health departments. Since the program’s creation in 1973, it has become one of the country’s most relevant public health interventions, having produced important results such as certification of Brazil as free of wild poliovirus circulation, the elimination rubella virus circulation, and an important reduction in cases and deaths from vaccine-preventable diseases. Brazil is one of the countries that offers the most vaccines free of cost to the population, with 15 vaccines for children, 9 for adolescents, and 5 for adults and the elderly. The program’s expansion and the maintenance of high vaccination coverage rates led to a rapid decrease in vaccine-preventable diseases, completely changing the epidemiological scenario of these diseases in Brazil in the last four decades. The country is currently witnessing an increasing share of the population without adequate vaccination. To the extent that these diseases are no longer circulating, precisely because of the high vaccination coverage rates, especially since the early 2000s, many of them are now unknown to the population. As a result, many people have no notion of the danger these diseases represent. We thus need to understand the multiple factors contributing to this decrease in coverage, which has created the risk of resurgence of serious diseases that had already been controlled or eliminated in Brazil.
A non-negligible proportion of human pathogenic variants are known to be present as wild type in at least some non-human mammalian species. The standard explanation for this finding is that molecular ...mechanisms of compensatory epistasis can alleviate the mutations’ otherwise pathogenic effects. Examples of compensated variants have been described in the literature but the interacting residue(s) postulated to play a compensatory role have rarely been ascertained. In this study, the examination of five human X-chromosomally encoded proteins (FIX, GLA, HPRT1, NDP and OTC) allowed us to identify several candidate compensated variants. Strong evidence for a compensated/compensatory pair of amino acids in the coagulation FIXa protein (involving residues 270 and 271) was found in a variety of mammalian species. Both amino acid residues are located within the 60-loop, spatially close to the 39-loop that performs a key role in coagulation serine proteases. To understand the nature of the underlying interactions, molecular dynamics simulations were performed. The predicted conformational change in the 39-loop consequent to the Glu270Lys substitution (associated with hemophilia B) appears to impair the protein’s interaction with its substrate but, importantly, such steric hindrance is largely mitigated in those proteins that carry the compensatory residue (Pro271) at the neighboring amino acid position.
A Molecular Perspective on Sirtuin Activity Teixeira, Carla S S; Cerqueira, Nuno M F S A; Gomes, Pedro ...
International journal of molecular sciences,
11/2020, Volume:
21, Issue:
22
Journal Article
Peer reviewed
Open access
The protein acetylation of either the α-amino groups of amino-terminal residues or of internal lysine or cysteine residues is one of the major posttranslational protein modifications that occur in ...the cell with repercussions at the protein as well as at the metabolome level. The lysine acetylation status is determined by the opposing activities of lysine acetyltransferases (KATs) and lysine deacetylases (KDACs), which add and remove acetyl groups from proteins, respectively. A special group of KDACs, named sirtuins, that require NAD
as a substrate have received particular attention in recent years. They play critical roles in metabolism, and their abnormal activity has been implicated in several diseases. Conversely, the modulation of their activity has been associated with protection from age-related cardiovascular and metabolic diseases and with increased longevity. The benefits of either activating or inhibiting these enzymes have turned sirtuins into attractive therapeutic targets, and considerable effort has been directed toward developing specific sirtuin modulators. This review summarizes the protein acylation/deacylation processes with a special focus on the current developments in the sirtuin research field.
Nature has tailored a wide range of metalloenzymes that play a vast array of functions in all living organisms and from which their survival and evolution depends on. These enzymes catalyze some of ...the most important biological processes in nature, such as photosynthesis, respiration, water oxidation, molecular oxygen reduction, and nitrogen fixation. They are also among the most proficient catalysts in terms of their activity, selectivity, and ability to operate at mild conditions of temperature, pH, and pressure. In the absence of these enzymes, these reactions would proceed very slowly, if at all, suggesting that these enzymes made the way for the emergence of life as we know today. In this review, the structure and catalytic mechanism of a selection of diverse metalloenzymes that are involved in the production of highly reactive and unstable species, such as hydroxide anions, hydrides, radical species, and superoxide molecules are analyzed. The formation of such reaction intermediates is very difficult to occur under biological conditions and only a rationalized selection of a particular metal ion, coordinated to a very specific group of ligands, and immersed in specific proteins allows these reactions to proceed. Interestingly, different metal coordination spheres can be used to produce the same reactive and unstable species, although through a different chemistry. A selection of hand-picked examples of different metalloenzymes illustrating this diversity is provided and the participation of different metal ions in similar reactions (but involving different mechanism) is discussed.
Self-Determination Theory (SDT) is amongst motivational frameworks the most popular and contemporary approach to human motivation, being applied in the last decades in several domains, including ...sport, exercise and physical education (PE). Additionally, Achievement Goal Theory (AGT) has presented evidence of how contextual factors may influence student's behavior in this particular context. The main purpose of this study was to analyze the motivational climate created by the teacher in the classroom, students' satisfaction of Basic Psychological Needs (BPN), and how their behavioral regulation could explain PE grades and intention to practice sports in the future.
A total of 618 students (290 female; 328 male) from the 6th to the 9th school level, aged between 10 and 18 years (M = 13.3; SD = 1.7) participated in this study. The following surveys were used for the proposed variables: Learning and Performance Orientations in Physical Education Classes Questionnaire (LAPOPECQ); the Basic Psychological Needs in Exercise Scale (BPNESp); and the Perceived Locus of Causality (PLOCp). Intentions to practice sport/physical activity in the future were assessed through a single item. Students' PE grade was obtained through his/her teacher final assessment. Structural Equation Analysis was performed via AMOS 23.0.
After analyzing modification indices and model adjustment, the final model emerged: learning climate > BPN > autonomous motivation > intentions/PE grade. Results interpretation seems to indicate that i) the satisfaction of BPN are influenced by motivational climate (i.e., learning climate), ii) the individuals' motivation is influenced by the satisfaction of three basic psychological needs (i.e., particularly competence), and iii) the motivational regulations have direct and significant effects with intention to practice sports outside school in the future and PE grades.
The main results showed that a climate oriented for learning has a positive impact on basic psychological needs satisfaction of students. However, only competence satisfaction had a significant positive relationship with students' autonomous motivation, which in turn had a significant positive relation with PE grade, as well as for intentions for leisure-time sport/physical activity practice.
The consumption of insects has increased in western countries, raising concerns about their potential to induce food allergic reactions in sensitized/allergic individuals. This work intended to ...develop a real-time PCR approach for the detection/quantification of yellow mealworm (
) as a potential allergenic food in complex matrices. For this purpose, reference mixtures simulating the production of pork sausages and wheat biscuits containing known amounts of mealworm were used. Real-time PCR with TaqMan probe targeting the cytochrome b gene of
was able to detect up to 2 fg of insect DNA, and 1.0 and 0.1 mg/kg of mealworm flour in autoclaved sausages and baked biscuits, respectively. Generally, the method showed acceptable analytical performance parameters, confirming its suitability/applicability for a wide range of foods. However, real-time PCR data showed significant differences among food matrix and processing, highlighting the importance of using appropriate calibration models for quantitative analysis. Finally, the real-time PCR approach was successfully validated with blind mixtures and applied to commercial samples, demonstrating its efficacy and reliability in the quantification of mealworm in processed foodstuffs.
Tryptophan Synthase (TSase) is an emergent therapeutic target in the treatment of tuberculosis. Interest in TSase as a drug target arose from the fact that this enzyme is not present in humans, while ...in bacteria, like M. tuberculosis, it catalyses the last two steps in the tryptophan biosynthetic pathway. Several inhibitors of TSase have recently been developed, with promising results. However, the exact catalytic mechanism of this enzyme has remained unexplained at the atomic level. The fact that TSase is a multifunctional enzyme, with two dimers, each one with two independent active sites, interconnected by a 25 Å tunnel, has made it a challenging enzyme, from the catalytic point of view. QM/MM calculations were used to analyze and explain the two steps catalyzed by this enzyme. The results provide an atomic‐level clarification of the full catalytic mechanism of this enzyme, offering also important clues for the development of new inhibitors against tuberculosis.
Mechanism of enzyme catalysis: QM/MM calculations were used to analyse and explain the two steps of the catalytic mechanism of tryptophan synthase. The results provide an atomic‐level clarification of the full catalytic mechanism of this enzyme, offering also important clues for the development of new inhibitors against tuberculosis.
Fighting cancer is one of the major challenges of the 21st century. Among recently proposed treatments, molecular-targeted therapies are attracting particular attention. The potential targets of such ...therapies include a group of enzymes that possess the capability to catalyze at least two different reactions, so-called multifunctional enzymes. The features of such enzymes can be used to good advantage in the development of potent selective inhibitors. This review discusses the potential of multifunctional enzymes as anti-cancer drug targets along with the current status of research into four enzymes which by their inhibition have already demonstrated promising anti-cancer effects in vivo, in vitro, or both. These are PFK-2/FBPase-2 (involved in glucose homeostasis), ATIC (involved in purine biosynthesis), LTA
H (involved in the inflammation process) and Jmjd6 (involved in histone and non-histone posttranslational modifications). Currently, only LTA
H and PFK-2/FBPase-2 have inhibitors in active clinical development. However, there are several studies proposing potential inhibitors targeting these four enzymes that, when used alone or in association with other drugs, may provide new alternatives for preventing cancer cell growth and proliferation and increasing the life expectancy of patients.
Worldwide, bacterial resistance to chemical antibiotics has reached such a high level that endangers public health. Presently, the adoption of alternative strategies that promote the elimination of ...resistant microbial strains from the environment is of utmost importance. This review discusses and analyses several (potential) alternative strategies to current chemical antibiotics. Bacteriophage (or phage) therapy, although not new, makes use of strictly lytic phage particles as an alternative, or a complement, in the antimicrobial treatment of bacterial infections. It is being rediscovered as a safe method, because these biological entities devoid of any metabolic machinery do not possess any affinity whatsoever to eukaryotic cells. Lysin therapy is also recognized as an innovative antimicrobial therapeutic option, since the topical administration of preparations containing purified recombinant lysins with amounts in the order of nanograms, in infections caused by Gram-positive bacteria, demonstrated a high therapeutic potential by causing immediate lysis of the target bacterial cells. Additionally, this therapy exhibits the potential to act synergistically when combined with certain chemical antibiotics already available on the market. Another potential alternative antimicrobial therapy is based on the use of antimicrobial peptides (AMPs), amphiphilic polypeptides that cause disruption of the bacterial membrane and can be used in the treatment of bacterial, fungal and viral infections, in the prevention of biofilm formation, and as antitumoral agents. Interestingly, bacteriocins are a common strategy of bacterial defense against other bacterial agents, eliminating the potential opponents of the former and increasing the number of available nutrients in the environment for their own growth. They can be applied in the food industry as biopreservatives and as probiotics, and also in fighting multi-resistant bacterial strains. The use of antibacterial antibodies promises to be extremely safe and effective. Additionally, vaccination emerges as one of the most promising preventive strategies. All these will be tackled in detail in this review paper.
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