Glycosidases and nanovesicles: novel biological tools for biotechnological applications.

Biocatalysis represents a versatile and valuable tool for industrial biotechnologies. The use of enzymes as biocatalysts has reached its present industrial level, due to their optimal reaction selectivity, high reaction rates, high product purity, and a significant decrease in the generation of chemical waste. The use of enzymes in industrial applications has been limited by several factors, mainly the high cost of enzymes, their instability, and their availability in small amounts. To overcome these problems, the quest for new catalytic activities and the development of new technical approaches, such as enzyme immobilization, to improve their stability and practical applications, remain a central focus of the current biotechnological research. In this PhD thesis, the biotechnological potential of a novel bacterial glycosidase (-RHA), and the characterization of two possible immobilization systems, bacterial OMVs and eukaryotic EVs is reported. More in detail, an optimized expression and purification procedure allowed to characterize a novel -RHA from the microorganism Novosphingobium sp. PP1Y, which resulted to be appealing from a biotechnological point of view for its interesting catalytic behaviour. Moreover, mutagenesis experiments, allowed a preliminary identification of the amminoacidic residues responsible for the catalytic activity of rRHA-P, which could be further mutagenized to fine-tune rRHA-P catalytic efficiency on selected substrates. In addition, two different potential scaffolds from bacteria (OMVs) and from an eukaryotic cell line (EVs) were isolated and characterized. Both systems resulted to be appealing either for enzyme immobilization or for drug-delivery strategies. In particular, OMVs isolated from N. sp. PP1Y were characterized by a peculiar biochemical composition, which showed some differences with the originating whole cells. EVs isolated from human macrophages resulted to have differential effects on inflammation activation, and their potential as a valid alternative to bacterial OMVs for the development of novel delivery Biosystems is discussed

Transcript Regulation of the Recoded Archaeal α-L-Fucosidase In Vivo

Genetic decoding is flexible, due to programmed deviation of the ribosomes from standard translational rules, globally termed “recoding”. In Archaea, recoding has been unequivocally determined only for termination codon readthrough events that regulate the incorporation of the unusual amino acids selenocysteine and pyrrolysine, and for −1 programmed frameshifting that allow the expression of a fully functional α-l-fucosidase in the crenarchaeon Saccharolobus solfataricus, in which several functional interrupted genes have been identified. Increasing evidence suggests that the flexibility of the genetic code decoding could provide an evolutionary advantage in extreme conditions, therefore, the identification and study of interrupted genes in extremophilic Archaea could be important from an astrobiological point of view, providing new information on the origin and evolution of the genetic code and on the limits of life on Earth. In order to shed some light on the mechanism of programmed −1 frameshifting in Archaea, here we report, for the first time, on the analysis of the transcription of this recoded archaeal α-l-fucosidase and of its full-length mutant in different growth conditions in vivo. We found that only the wild type mRNA significantly increased in S. solfataricus after cold shock and in cells grown in minimal medium containing hydrolyzed xyloglucan as carbon source. Our results indicated that the increased level of fucA mRNA cannot be explained by transcript up-regulation alone. A different mechanism related to translation efficiency is discusse

Genetic risk and a primary role for cell-mediated immune mechanisms in multiple sclerosis.

Multiple sclerosis is a common disease of the central nervous system in which the interplay between inflammatory and neurodegenerative processes typically results in intermittent neurological disturbance followed by progressive accumulation of disability. Epidemiological studies have shown that genetic factors are primarily responsible for the substantially increased frequency of the disease seen in the relatives of affected individuals, and systematic attempts to identify linkage in multiplex families have confirmed that variation within the major histocompatibility complex (MHC) exerts the greatest individual effect on risk. Modestly powered genome-wide association studies (GWAS) have enabled more than 20 additional risk loci to be identified and have shown that multiple variants exerting modest individual effects have a key role in disease susceptibility. Most of the genetic architecture underlying susceptibility to the disease remains to be defined and is anticipated to require the analysis of sample sizes that are beyond the numbers currently available to individual research groups. In a collaborative GWAS involving 9,772 cases of European descent collected by 23 research groups working in 15 different countries, we have replicated almost all of the previously suggested associations and identified at least a further 29 novel susceptibility loci. Within the MHC we have refined the identity of the HLA-DRB1 risk alleles and confirmed that variation in the HLA-A gene underlies the independent protective effect attributable to the class I region. Immunologically relevant genes are significantly overrepresented among those mapping close to the identified loci and particularly implicate T-helper-cell differentiation in the pathogenesis of multiple sclerosis

Amor constante : Quevedo más allá de la muerte

La col·lecció Studia Aurea Monográfica, coeditada por la Universitat Autònoma de Barcelona y la Universitat de Girona, es una colección auspiciada por Studia Aurea. Revista de Literatura Española y Teoría Literaria del Renacimiento y Siglo de Oro.Els capítols d'aquest llibre els trobareu també al Dipòsit digital de documents de la UAB en text complet.El estudio de la recepción de la obra de Quevedo como 'clásico contemporáneo' se enriquece hoy con la publicación de una serie de ensayos que, por su propia naturaleza específica y variedad del conjunto, proporcionan y confirman un dato incontrovertible: Quevedo no solo es un modelo literario, sino un arquetipo, de la cultura y del pensamiento; su obra no solo vale como antecedente o hipotexto, sino que funciona como verdadero sistema comunicativo, disponible al uso de las distintas formas de la expresión humana

Effect of Hydrocortisone on Mortality and Organ Support in Patients With Severe COVID-19: The REMAP-CAP COVID-19 Corticosteroid Domain Randomized Clinical Trial.

Importance: Evidence regarding corticosteroid use for severe coronavirus disease 2019 (COVID-19) is limited. Objective: To determine whether hydrocortisone improves outcome for patients with severe COVID-19. Design, Setting, and Participants: An ongoing adaptive platform trial testing multiple interventions within multiple therapeutic domains, for example, antiviral agents, corticosteroids, or immunoglobulin. Between March 9 and June 17, 2020, 614 adult patients with suspected or confirmed COVID-19 were enrolled and randomized within at least 1 domain following admission to an intensive care unit (ICU) for respiratory or cardiovascular organ support at 121 sites in 8 countries. Of these, 403 were randomized to open-label interventions within the corticosteroid domain. The domain was halted after results from another trial were released. Follow-up ended August 12, 2020. Interventions: The corticosteroid domain randomized participants to a fixed 7-day course of intravenous hydrocortisone (50 mg or 100 mg every 6 hours) (n = 143), a shock-dependent course (50 mg every 6 hours when shock was clinically evident) (n = 152), or no hydrocortisone (n = 108). Main Outcomes and Measures: The primary end point was organ support-free days (days alive and free of ICU-based respiratory or cardiovascular support) within 21 days, where patients who died were assigned -1 day. The primary analysis was a bayesian cumulative logistic model that included all patients enrolled with severe COVID-19, adjusting for age, sex, site, region, time, assignment to interventions within other domains, and domain and intervention eligibility. Superiority was defined as the posterior probability of an odds ratio greater than 1 (threshold for trial conclusion of superiority >99%). Results: After excluding 19 participants who withdrew consent, there were 384 patients (mean age, 60 years; 29% female) randomized to the fixed-dose (n = 137), shock-dependent (n = 146), and no (n = 101) hydrocortisone groups; 379 (99%) completed the study and were included in the analysis. The mean age for the 3 groups ranged between 59.5 and 60.4 years; most patients were male (range, 70.6%-71.5%); mean body mass index ranged between 29.7 and 30.9; and patients receiving mechanical ventilation ranged between 50.0% and 63.5%. For the fixed-dose, shock-dependent, and no hydrocortisone groups, respectively, the median organ support-free days were 0 (IQR, -1 to 15), 0 (IQR, -1 to 13), and 0 (-1 to 11) days (composed of 30%, 26%, and 33% mortality rates and 11.5, 9.5, and 6 median organ support-free days among survivors). The median adjusted odds ratio and bayesian probability of superiority were 1.43 (95% credible interval, 0.91-2.27) and 93% for fixed-dose hydrocortisone, respectively, and were 1.22 (95% credible interval, 0.76-1.94) and 80% for shock-dependent hydrocortisone compared with no hydrocortisone. Serious adverse events were reported in 4 (3%), 5 (3%), and 1 (1%) patients in the fixed-dose, shock-dependent, and no hydrocortisone groups, respectively. Conclusions and Relevance: Among patients with severe COVID-19, treatment with a 7-day fixed-dose course of hydrocortisone or shock-dependent dosing of hydrocortisone, compared with no hydrocortisone, resulted in 93% and 80% probabilities of superiority with regard to the odds of improvement in organ support-free days within 21 days. However, the trial was stopped early and no treatment strategy met prespecified criteria for statistical superiority, precluding definitive conclusions. Trial Registration: ClinicalTrials.gov Identifier: NCT02735707

Low-Frequency and Rare-Coding Variation Contributes to Multiple Sclerosis Risk

Multiple sclerosis is a complex neurological disease, with 3c20% of risk heritability attributable to common genetic variants, including >230 identified by genome-wide association studies. Multiple strands of evidence suggest that much of the remaining heritability is also due to additive effects of common variants rather than epistasis between these variants or mutations exclusive to individual families. Here, we show in 68,379 cases and controls that up to 5% of this heritability is explained by low-frequency variation in gene coding sequence. We identify four novel genes driving MS risk independently of common-variant signals, highlighting key pathogenic roles for regulatory T cell homeostasis and regulation, IFN\u3b3 biology, and NF\u3baB signaling. As low-frequency variants do not show substantial linkage disequilibrium with other variants, and as coding variants are more interpretable and experimentally tractable than non-coding variation, our discoveries constitute a rich resource for dissecting the pathobiology of MS. In a large multi-cohort study, unexplained heritability for multiple sclerosis is detected in low-frequency coding variants that are missed by GWAS analyses, further underscoring the role of immune genes in MS pathology

Archaea as a Model System for Molecular Biology and Biotechnology

Archaea represents the third domain of life, displaying a closer relationship with eukaryotes than bacteria. These microorganisms are valuable model systems for molecular biology and biotechnology. In fact, nowadays, methanogens, halophiles, thermophilic euryarchaeota, and crenarchaeota are the four groups of archaea for which genetic systems have been well established, making them suitable as model systems and allowing for the increasing study of archaeal genes’ functions. Furthermore, thermophiles are used to explore several aspects of archaeal biology, such as stress responses, DNA replication and repair, transcription, translation and its regulation mechanisms, CRISPR systems, and carbon and energy metabolism. Extremophilic archaea also represent a valuable source of new biomolecules for biological and biotechnological applications, and there is growing interest in the development of engineered strains. In this review, we report on some of the most important aspects of the use of archaea as a model system for genetic evolution, the development of genetic tools, and their application for the elucidation of the basal molecular mechanisms in this domain of life. Furthermore, an overview on the discovery of new enzymes of biotechnological interest from archaea thriving in extreme environments is reported

Novel Drug Targets for the Treatment of Cardiac Diseases

Background: Cardiovascular disease is the leading cause of morbidity and mortality worldwide in developed countries, and its social and economic burden is expected to increase dramatically over the next decades. Despite significative improvement in the pharmacological treatment, and the huge advances in prevention, the quest for new molecular targets and for novel, more efficient and personalized therapies is still a priority for this group of pathologies. Objective: The paramount complexity of the metabolic networks responsible for the onset and progression of cardiovascular disease is highlighted by the wide and diverse array of new molecular targets recently described in literature. In this brief review, we focused our interest on a subset of promising molecular targets for the development of new pharmacological treatments specific for cardiac diseases such as coronary artery disease, heart failure and myocardial infarction. Conclusion: The global quest for new molecular targets for the treatment of cardiac diseases is leading to an impressive amount of records in the more recent literature. Although several promising molecular pathways have been identified so far, great caution should be used in considering all these targets effective in promoting the production of new drugs. The identification of suitable therapeutic targets is in fact an ongoing challenge that often lacks enough pre-clinical and clinical studies, which hinders the effective utilization of several new drugs due to a lack of efficacy or induction of safety liabilities

The marine Gram-negative bacterium Novosphingobium sp. PP1Y as a potential source of novel metabolites with antioxidant activity

Objective The antioxidant activity and protective effect of a methanolic extract obtained from the marine Gram-negative bacterium Novosphingobium sp. PP1Y, isolated from the surface water of a polluted area in the harbour of Pozzuoli (Naples, Italy), was evaluated. Results The extract was tested in vitro on epithelial colorectal adenocarcinoma cells and in vivo on Caenorhabditis elegans. It showed strong protective activity against oxidative stress, in both experimental systems, by preventing ROS accumulation. In the case of the cells, pre-treatment with methanolic extract was also able to maintain unaltered intracellular GSH levels and phosphorylation levels of mitogen-activated protein kinases p38. Instead, in the case of the worms, the extract was able to modulate the expression levels of stress response genes, by activating the transcription factor skn-1. Conclusions From a biotechnological and economical point of view, antioxidants from microorganisms are convenient as they provide a valid alternative to chemical synthesis and respond to the ever-growing market demand for natural antioxidants