Development of a rapid assay for ß-etherase activity using a novel chromogenic substrate.

Biocatalytic processes play a crucial role in the valorization of lignin; therefore, methods enabling the monitoring of enzymes such as ß-etherases, capable of breaking ß-O-4 aryl-ether bonds, are of significant biotechnological interest. A novel method for quantifying ß-etherase activity was developed based on the ß-ester bond formation between a chromophore and acetovainillone. The chromogenic substrate ß-(ρ-nitrophenoxy)-α-acetovanillone (PNPAV), was chemically synthesized. Kintetic monitoring of ρ-nitrophenolate release at 410 nm over 10 min, using recombinant LigF from Sphingobium sp SYK-6, LigF-AB and LigE-AB from Althererytrobacter sp B11, yielded enzimatic activities of 404. 3 mU/mg, 72 mU/mg, and 50 mU/mg, respectively. This method is applicable in a pH range of 7.0-9.0, with a sensitivity of up to 50 ng of enzyme, exhibiting no interference with lipolytic, glycolytic, proteolytic, and oxidoreductase enzymes.

Cloning, expression, and biochemical characterization of ß-etherase LigF from Altererythrobacter sp. B11.

Lignin, a complex heteropolymer present in plant cell walls, is now recognized as a valuable renewable resource with potential applications in various industries. The lignin biorefinery concept, which aims to convert lignin into value-added products, has gained significant attention in recent years. ß-etherases, enzymes that selectively cleave ß-O-4 aryl ether bonds in lignin, have shown promise in lignin depolymerization. In this study, the ß-etherase LigF from Altererythrobacter sp. B11 was cloned, expressed, purified, and biochemically characterized. The LigF-AB11 enzyme exhibited optimal activity at 32 °C and pH 8.5 when catalyzing the substrate PNP-AV. The enzyme displayed mesophilic behavior and demonstrated higher activity at moderate temperatures. Stability analysis revealed that LigF-AB11 was not thermostable, with a complete loss of activity at 60 °C within an hour. Moreover, LigF-AB11 exhibited excellent pH stability, retaining over 50 % of its activity after 1 h under pH conditions ranging from 3.0 to 11.0. Metal ions and surface impregnation agents were found to affect the enzyme's activity, highlighting the importance of considering these factors in enzymatic processes for lignin depolymerization. This study provides valuable insights into the biochemical properties of LigF-AB11 and contributes to the development of efficient enzymatic processes for lignin biorefineries. Further optimization and understanding of ß-etherases will facilitate their practical application in the valorization of lignin.

Bi-allelic variants in the ESAM tight-junction gene cause a neurodevelopmental disorder associated with fetal intracranial hemorrhage.

The blood-brain barrier (BBB) is an essential gatekeeper for the central nervous system and incidence of neurodevelopmental disorders (NDDs) is higher in infants with a history of intracerebral hemorrhage (ICH). We discovered a rare disease trait in thirteen individuals, including four fetuses, from eight unrelated families associated with homozygous loss-of-function variant alleles of ESAM which encodes an endothelial cell adhesion molecule. The c.115del (p.Arg39Glyfs∗33) variant, identified in six individuals from four independent families of Southeastern Anatolia, severely impaired the in vitro tubulogenic process of endothelial colony-forming cells, recapitulating previous evidence in null mice, and caused lack of ESAM expression in the capillary endothelial cells of damaged brain. Affected individuals with bi-allelic ESAM variants showed profound global developmental delay/unspecified intellectual disability, epilepsy, absent or severely delayed speech, varying degrees of spasticity, ventriculomegaly, and ICH/cerebral calcifications, the latter being also observed in the fetuses. Phenotypic traits observed in individuals with bi-allelic ESAM variants overlap very closely with other known conditions characterized by endothelial dysfunction due to mutation of genes encoding tight junction molecules. Our findings emphasize the role of brain endothelial dysfunction in NDDs and contribute to the expansion of an emerging group of diseases that we propose to rename as "tightjunctionopathies."

Aft1 Nuclear Localization and Transcriptional Response to Iron Starvation Rely upon TORC2/Ypk1 Signaling and Sphingolipid Biosynthesis.

Iron scarcity provokes a cellular response consisting of the strong expression of high-affinity systems to optimize iron uptake and mobilization. Aft1 is a primary transcription factor involved in iron homeostasis and controls the expression of high-affinity iron uptake genes in Saccharomyces cerevisiae. Aft1 responds to iron deprivation by translocating from the cytoplasm to the nucleus. Here, we demonstrate that the AGC kinase Ypk1, as well as its upstream regulator TOR Complex 2 (TORC2), are required for proper Aft1 nuclear localization following iron deprivation. We exclude a role for TOR Complex 1 (TORC1) and its downstream effector Sch9, suggesting this response is specific for the TORC2 arm of the TOR pathway. Remarkably, we demonstrate that Aft1 nuclear localization and a robust transcriptional response to iron starvation also require biosynthesis of sphingolipids, including complex sphingolipids such as inositol phosphorylceramide (IPC) and upstream precursors, e.g., long-chain bases (LCBs) and ceramides. Furthermore, we observe the deficiency of Aft1 nuclear localization and impaired transcriptional response in the absence of iron when TORC2-Ypk1 is impaired is partially suppressed by exogenous addition of the LCB dihydrosphingosine (DHS). This latter result is consistent with prior studies linking sphingolipid biosynthesis to TORC2-Ypk1 signaling. Taken together, these results reveal a novel role for sphingolipids, controlled by TORC2-Ypk1, for proper localization and activity of Aft1 in response to iron scarcity.

Both human and soya bean ferritins highly improve the accumulation of bioavailable iron and contribute to extend the chronological life in budding yeast.

Ferritin proteins have an enormous capacity to store iron in cells. In search for the best conditions to accumulate and store bioavailable iron, we made use of a double mutant null for the monothiol glutaredoxins GRX3 and GRX4. The strain grx3grx4 accumulates high iron concentrations in the cytoplasm, making the metal easily available for ferritin chelation. Here, we perform a comparative study between human (L and H) and soya bean ferritins (H1 and H2) function in the eukaryotic system Saccharomyces cerevisiae. We demonstrate that the four human and soya bean ferritin chains are successfully expressed in our model system. Upon coexpression of either both human or soya bean ferritin chains, respiratory conditions along with iron supplementation led us to obtain the maximum yields of iron stored in yeast described to date. Human and soya bean ferritin chains are functional and present equivalent properties as promoters of cell survival in iron overload conditions. The best system revealed that the four human and soya bean ferritins possess a novel function as anti-ageing proteins in conditions of iron excess. In this respect, both ferritin chains with oxidoreductase capacity (human-H and soya bean-H2) bear the highest capacity to extend life suggesting the possibility of an evolutionary conservation.

Recent advances and new insights in the management of early-stage epidermal growth factor receptor-mutated non-small-cell lung cancer.

Patients with early-stage non-small-cell lung cancer (NSCLC) are candidates for curative surgery; however, despite multiple advances in lung cancer management, recurrence rates remain high. Adjuvant chemotherapy has been demonstrated to significantly prolong overall survival (OS), but this benefit is modest and there is an urgent need for effective new therapies to provide a cure for more patients. The high efficacy of tyrosine kinase inhibitors (TKIs) against epidermal growth factor receptor-mutated (EGFR) in patients with advanced EGFR-mutated NSCLC has led to the evaluation of these agents in early stages of the disease. Multiple clinical trials have evaluated the safety and efficacy of EGFR TKIs as an adjuvant treatment, in patients with resected EGFR-mutated NSCLC, and shown that they significantly prolong disease-free survival (DFS), but this benefit does not translate to OS. Recently, an interim analysis of the ADAURA trial demonstrated that, surprisingly, osimertinib improved DFS. This led to the study being stopped early, leaving many unanswered questions about its potential effect on OS and its incorporation as a standard adjuvant treatment in this patient subgroup. These targeted agents are also being evaluated in locally-advanced disease, with promising results, although prospective studies with larger sample sizes are needed to confirm these results. In this article, we review the most relevant studies on the role of EGFR TKIs in the management of early-stage EGFR-mutated NSCLC.

The Cell Wall Integrity Receptor Mtl1 Contributes to Articulate Autophagic Responses When Glucose Availability Is Compromised.

Mtl1protein is a cell wall receptor belonging to the CWI pathway. Mtl1 function is related to glucose and oxidative stress signaling. In this report, we show data demonstrating that Mtl1 plays a critical role in the detection of a descent in glucose concentration, in order to activate bulk autophagy machinery as a response to nutrient deprivation and to maintain cell survival in starvation conditions. Autophagy is a tightly regulated mechanism involving several signaling pathways. The data here show that in Saccharomyces cerevisiae, Mtl1 signals glucose availability to either Ras2 or Sch9 proteins converging in Atg1 phosphorylation and autophagy induction. TORC1 complex function is not involved in autophagy induction during the diauxic shift when glucose is limited. In this context, the GCN2 gene is required to regulate autophagy activation upon amino acid starvation independent of the TORC1 complex. Mtl1 function is also involved in signaling the autophagic degradation of mitochondria during the stationary phase through both Ras2 and Sch9, in a manner dependent on either Atg33 and Atg11 proteins and independent of the Atg32 protein, the mitophagy receptor. All of the above suggest a pivotal signaling role for Mtl1 in maintaining correct cell homeostasis function in periods of glucose scarcity in budding yeast.

Description of the molecular and clinical characteristics of the mucopolysaccharidosis type VII Iberian cohort.

BACKGROUND: Mucopolysaccharidosis type VII (Sly syndrome) is an ultra-rare neurometabolic disorder caused by inherited deficiency of the lysosomal enzyme ß-glucuronidase. Precise data regarding its epidemiology are scarce, but birth prevalence is estimated to vary from 0.02 to 0.24 per 100,000 live births. The clinical course and disease progression are widely heterogeneous, but most patients have been reported to show signs such as skeletal deformities or cognitive delay. Additionally, detection criteria are not standardized, resulting in delayed diagnosis and treatment. METHODS: We present a cohort of 9 patients with mucopolysaccharidosis VII diagnosed in the Iberian Peninsula, either in Spain or Portugal. The diagnostic approach, genetic studies, clinical features, evolution and treatment interventions were reviewed. RESULTS: We found that skeletal deformities, hip dysplasia, hydrops fetalis, hepatosplenomegaly, hernias, coarse features, respiratory issues, and cognitive and growth delay were the most common features identified in the cohort. In general, patients with early diagnostic confirmation who received the appropriate treatment in a timely manner presented a more favorable clinical evolution. CONCLUSIONS: This case series report helps to improve understanding of this ultra-rare disease and allows to establish criteria for clinical suspicion or diagnosis, recommendations, and future directions for better management of patients with Sly syndrome.

GOECP/SEOR clinical guidelines on radiotherapy for malignant pleural mesothelioma.

Malignant pleural mesothelioma (MPM) is a rare tumor with poor prognosis and rising incidence. Palliative care is common in MPM as radical treatment with curative intent is often not possible due to metastasis or extensive locoregional involvement. Numerous therapeutic advances have been made in recent years, including the use of less aggressive surgical techniques associated with lower morbidity and mortality (e.g., pleurectomy/decortication), technological advancements in the field of radiotherapy (intensity-modulated radiotherapy, image-guided radiotherapy, stereotactic body radiotherapy, proton therapy), and developments in systemic therapies (chemotherapy and immunotherapy). These improvements have had as yet only a modest effect on local control and survival. Advances in the management of MPM and standardization of care are hampered by the evidence to date, limited by high heterogeneity among studies and small sample sizes. In this clinical guideline prepared by the oncological group for the study of lung cancer of the Spanish Society of Radiation Oncology, we review clinical, histologic, and therapeutic aspects of MPM, with a particular focus on all aspects relating to radiotherapy, including the current evidence base, associations with chemotherapy and surgery, treatment volumes and planning, technological advances, and reradiation.

The MAPK Slt2/Mpk1 plays a role in iron homeostasis through direct regulation of the transcription factor Aft1.

Iron is an essential element for life. Cells develop mechanisms to tightly regulate its homeostasis, in order to avoid abnormal accumulation and the consequent cell toxicity. In budding yeast, the high affinity iron regulon is under the control of the transcription factor Aft1. We present evidence demonstrating that the MAPK Slt2 of the cell wall integrity pathway (CWI), phosphorylates and negatively regulates Aft1 activity upon the iron depletion signal, both in fermentative or respiratory conditions. The lack of Slt2 provokes Aft1 dysfunction leading to a shorter chronological life span. The signal of iron scarcity is not transmitted to Slt2 through other signalling pathways such as TOR1, PKA, SNF1 or TOR2/YPK1. The observation that Slt2 physically binds Aft1 rather suggests a direct regulation.

Bulk autophagy induction and life extension is achieved when iron is the only limited nutrient in Saccharomyces cerevisiae.

We have investigated the effects that iron limitation provokes in Saccharomyces cerevisiae exponential cultures. We have demonstrated that one primary response is the induction of bulk autophagy mediated by TORC1. Coherently, Atg13 became dephosphorylated whereas Atg1 appeared phosphorylated. The signal of iron deprivation requires Tor2/Ypk1 activity and the inactivation of Tor1 leading to Atg13 dephosphorylation, thus triggering the autophagy process. Iron replenishment in its turn, reduces autophagy flux through the AMPK Snf1 and the subsequent activity of the iron-responsive transcription factor, Aft1. This signalling converges in Atg13 phosphorylation mediated by Tor1. Iron limitation promotes accumulation of trehalose and the increase in stress resistance leading to a quiescent state in cells. All these effects contribute to the extension of the chronological life, in a manner totally dependent on autophagy activation.

A sensitive pH indicator-based spectrophotometric assay for PHB depolymerase activity on microtiter plates.

A continuous spectrophotometric assay for the screening of PHB depolymerase activity in microtiter plates was developed. We evaluated crystalline PHB in the suspension and coated it with the addition of a pH indicator to detect the breakage of the ester bond by proton titration. The reaction rate and the concentration of the recombinant PhaZ1 from Paucimonas lemoignei PHB depolymerase presented a linear correlation. A comparison of the proposed method with the turbidimetric method adapted to the microtiter plates revealed that the use of indicators increases the response signal by at least 5-fold, resulting in increased sensitivity and better signal-to-noise ratio. Furthermore, the proposed method offers a wide range of pH from 5.0 to 9.2 by using different buffer-indicator pairs and was employed for the screening of PHB-depolymerase activity on 140 bacterial strains isolated from Lake Chapala. Eleven strains were positive for PHB-depolymerase activity, which were ACSLRF-27, ACPLRF-6, and ACPLRF-5 (16S rRNA sequence alignment revealed 99-100% similarity with Actinomadura geliboluensis strain A8036, Streptomyces cavourensis strain NRRL 2740, and Streptomyces coelicolor strain DSM 40233, respectively); these that showed the highest activities. In conclusion, the method was successfully applied for finding new strains and for quantifying the PHB depolymerases activity with crystalline PHB.

Interactions of GMP with Human Glrx3 and with Saccharomyces cerevisiae Grx3 and Grx4 Converge in the Regulation of the Gcn2 Pathway.

The human monothiol glutaredoxin Glrx3 (PICOT) is ubiquitously distributed in cytoplasm and nuclei in mammalian cells. Its overexpression has been associated with the development of several types of tumors, whereas its deficiency might cause retardation in embryogenesis. Its exact biological role has not been well resolved, although a function as a chaperone distributing iron/sulfur clusters is currently accepted. Yeast humanization and the use of a mouse library have allowed us to find a new partner for PICOT: the human GMP synthase (hGMPs). Both proteins carry out collaborative functions regarding the downregulation of the Saccharomyces cerevisiae Gcn2 pathway under conditions of nutritional stress. Glrx3/hGMPs interact through conserved residues that bridge iron/sulfur clusters and glutathione. This mechanism is also conserved in budding yeast, whose proteins Grx3/Grx4, along with GUA1 (S. cerevisiae GMPs), also downregulate the integrated stress response (ISR) pathway. The heterologous expression of Glrx3/hGMPs efficiently complements Grx3/Grx4. Moreover, the heterologous expression of Glrx3 efficiently complements the novel participation in chronological life span that has been characterized for both Grx3 and Grx4. Our results underscore that the Glrx3/Grx3/Grx4 family presents an evolutionary and functional conservation in signaling events that is partly related to GMP function and contributes to cell life extension.IMPORTANCESaccharomyces cerevisiae is an optimal eukaryotic microbial model to study biological processes in higher organisms despite the divergence in evolution. The molecular function of yeast glutaredoxins Grx3 and Grx4 is enormously interesting, since both proteins are required to maintain correct iron homeostasis and an efficient response to oxidative stress. The human orthologous Glrx3 (PICOT) is involved in a number of human diseases, including cancer. Our research expanded its utility to human cells. Yeast has allowed the characterization of GMP synthase as a new interacting partner for Glrx3 and also for yeast Grx3 and Grx4, the complex monothiol glutaredoxins/GMPs that participate in the downregulation of the activity of the Gcn2 stress pathway. This mechanism is conserved in yeast and humans. Here, we also show that this family of glutaredoxins, Grx3/Grx4/Glrx3, also has a function related to life extension.

Hyperthermia-induced seizures produce long-term effects on the functionality of adenosine A1 receptor in rat cerebral cortex.

Febrile seizures are one of the most frequent childhood neurological disorders; they are classified into simple and prolonged, depending on their duration. Prolonged FS lasts more than 15 min and may evoke neurological sequelae in a process in which molecular alterations seem to play an important role. Adenosine is a purine nucleoside that exerts anticonvulsant effects through binding to adenosine A1 receptor (A1 R). This receptor belongs to the GPCR superfamily and is negatively coupled to adenylyl cyclase (AC) activity through Gi proteins. In the present study, we analyzed the functionality of A1 R, measured as the inhibition of forskolin-stimulated AC activity, 48 hr after hyperthermia-induced seizures (HIS). Surprisingly, the results obtained show that the activation of A1 R increased forskolin-stimulated cAMP production instead of decreasing it. This alteration was not accompanied by changes in αG protein levels. The functionality of A1 R remained altered two months after HIS. However, this alteration was abolished when AC assays were carried out in the presence of anti αGs subunit-specific antibody, suggesting that HIS can switch A1 R coupling from Gi to Gs proteins. Finally, radioligand binding assays revealed that density and affinity of A1 R were not significantly altered by HIS. In summary, the results obtained show that HIS induces long-term changes in the A1 R/AC signaling pathway in rat brain cortex.

Screening of Gastrointestinal Lipase Inhibitors Produced by Microorganisms Isolated from Soil and Lake Sediments.

Gastrointestinal lipase inhibitors are molecules of pharmaceutical interest due to their use as anti-obesity drugs. In this study, forty strains isolated from soil and sediments were identified with the ability to produce inhibition of gastrointestinal lipase activity. The biomass extract of these strains showed at least 50% inhibition in the hydrolysis of tributyrin by recombinant human pancreatic lipase (rHPL) or rabbit gastric lipase (RGL) by in vitro assays. Based on gene sequencing, the isolates were identified mainly as Streptomycetes. Moreover, none of the identified strains has been reported to be lipase inhibitor producers, so they can be viewed as potential sources for obtaining new drugs. IC50 values of the three best inhibitor extracts showed that AC104-10 was the most promising strain for production of gastrointestinal lipase inhibitors. AC104-10 shows 99% homology (16S rRNA gene fragment) to Streptomyces cinereoruber strain NBRC 12756. An inhibitory study over trypsin activity revealed that AC104-10 extract, as well as THL, had no significant effect on the activity of this protease, showing its specificity for lipases. In addition, analyzes by MALDI-TOF mass spectrometry of the enzyme-inhibitor complex revealed that there is a covalent interaction of the AC104-10 inhibitor with the catalytic serine of the pancreatic lipase, and that the molecular weight of the inhibitor is approximately 686.19 Da.

The image of physical education teachers held by students from two universities / A imagem dos professores de educação física de alunos de duas universidades

ABSTRACT This study analyses the image that students of initial physical education teacher education (PETE) from two different universities (University of Alicante- UA, Spain, and Central University of Ecuador-UCE) have of physical education teachers. This qualitative and comparative study uses a metaphorical approach. Qualitative methodology was used to analyse the participating students metaphors in order to explore whether or not they suit the current learning and teaching perspectives in the field of Physical Education, and whether the images conveyed any differences between universities due to the influence of the context in the Physical Education teacher image and in gender stereotypes. A total of 190 students participated in the study (n= 105 men; n= 85 women). The software AQUAD 7 was used to process the data. The results showed that there were no obvious gender differences that keep women away from physical activity. As well as not excessive differences due to the different context of the participants.

RESUMO Este estudo analisa a imagem que alunos de educação inicial de professores de educação física de duas universidades diferentes (Universidade de Alicante - UA, Espanha e Universidade Central do Equador - UCE) possuem professores de educação física. Este estudo qualitativo e comparativo utiliza uma abordagem metafórica. A metodologia qualitativa foi utilizada para analisar as metáforas dos alunos participantes, a fim de explorar se elas se adequam ou não às perspectivas atuais de aprendizagem e ensino no campo da Educação Física, e se as imagens transmitiram alguma diferença entre as universidades devido à influência do contexto na imagem do professor de Educação Física e nos estereótipos de gênero. Um total de 190 alunos participaram do estudo (n= 105 homens; n= 85 mulheres). O software AQUAD 7 foi utilizado para processar os dados. Os resultados mostraram que não havia diferenças de gênero óbvias que afastassem as mulheres da atividade física. Assim como não há diferenças excessivas devido ao contexto diferente dos participantes.

A genome-wide transcriptional study reveals that iron deficiency inhibits the yeast TORC1 pathway.

Iron is an essential micronutrient that participates as a cofactor in a broad range of metabolic processes including mitochondrial respiration, DNA replication, protein translation and lipid biosynthesis. Adaptation to iron deficiency requires the global reorganization of cellular metabolism directed to optimize iron utilization. The budding yeast Saccharomyces cerevisiae has been widely used to characterize the responses of eukaryotic microorganisms to iron depletion. In this report, we used a genomic approach to investigate the contribution of transcription rates to the modulation of mRNA levels during adaptation of yeast cells to iron starvation. We reveal that a decrease in the activity of all RNA polymerases contributes to the down-regulation of many mRNAs, tRNAs and rRNAs. Opposite to the general expression pattern, many genes including components of the iron deficiency response, the mitochondrial retrograde pathway and the general stress response display a remarkable increase in both transcription rates and mRNA levels upon iron limitation, whereas genes encoding ribosomal proteins or implicated in ribosome biogenesis exhibit a pronounced fall. This expression profile is consistent with an activation of the environmental stress response. The phosphorylation stage of multiple regulatory factors strongly suggests that the conserved nutrient signaling pathway TORC1 is inhibited during the progress of iron deficiency. These results suggest an intricate crosstalk between iron metabolism and the TORC1 pathway that should be considered in many disorders.

Short-term perioperative iron in major orthopedic surgery: state of the art.

In major orthopaedic surgery, it is recommended to detect and correct preoperative anaemia several weeks prior to surgery. However, in many cases, the procedure is urgent or the patient is evaluated shortly before the intervention. As iron deficiency is the leading cause of perioperative anaemia, an exhaustive review of the literature was performed to assess the efficacy and safety of short-term perioperative intravenous, with or without erythropoietin, or postoperative oral or intravenous supplementation in major orthopaedic surgery. Overall, 20 studies met the inclusion criteria. There were 13 randomized trials (moderate quality) and seven observational studies (low to very low quality). The primary outcomes were reduction in transfusion requirements, haemoglobin increase and medication side-effects during the study period. Data analysis showed that postoperative oral iron administration neither increased haemoglobin nor reduced transfusion requirements, and it was associated with significant gastrointestinal adverse effects (15%). In contrast, for some patient populations, perioperative or postoperative administration of intravenous iron, with or without recombinant erythropoietin, may reduce transfusion requirements and/or hasten the recovery from postoperative, with few clinically relevant adverse effects (<2%). However, discrepancies between randomized trials and observational studies on the possible beneficial effects of short-term perioperative intravenous iron administration were found for patients undergoing surgery for hip fracture repair. Further studies are needed to elucidate when the treatment should be started, which combination of drugs should be used, and which patient groups would be most benefit.