Sugar nucleotide quantification by liquid chromatography tandem mass spectrometry reveals a distinct profile in Plasmodium falciparum sexual stage parasites

The obligate intracellular lifestyle of Plasmodium falciparum and the difficulties to obtain sufficient amounts of biological material has hampered the study of specific metabolic pathways in the malaria parasite. Thus, for example, the pools of sugar nucleotides required to fuel glycosylation reactions have never been studied in-depth in well-synchronized asexual parasites or in other stages of its life cycle. These metabolites are of critical importance, especially considering the renewed interest in the presence of N -, O - and other glycans in key parasite proteins. In this work, we adapted a liquid chromatography tandem mass spectrometry method based on the use of porous graphitic carbon (PGC) columns and MS-friendly solvents to quantify sugar nucleotides in the malaria parasite. We report on the thorough quantification of the pools of these metabolites throughout the intraerythrocytic cycle of P. falciparum The sensitivity of the method enabled for the first time the targeted analysis of these glycosylation precursors in gametocytes, the parasite sexual stages that are transmissible to the mosquito vector

A Plasmodium falciparum C-mannosyltransferase is dispensable for parasite asexual blood stage development

C-mannosylation was recently identified in the thrombospondin-related anonymous protein (TRAP) from Plasmodium falciparum salivary gland sporozoites. A candidate P. falciparum C-mannosyltransferase (Pf DPY-19) was demonstrated to modify thrombospondin type 1 repeat (TSR) domains in vitro, exhibiting a different acceptor specificity than their mammalian counterparts. According to the described minimal acceptor of Pf DPY19, several TSR domain-containing proteins of P. falciparum could be C-mannosylated in vivo. However, the relevance of this protein modification for the parasite viability remains unknown. In the present study, we used CRISPR/Cas9 technology to generate a Pf DPY19 null mutant, demonstrating that this glycosyltransferase is not essential for the asexual blood development of the parasite. Pf DPY19 gene disruption was not associated with a growth phenotype, not even under endoplasmic reticulum-stressing conditions that could impair protein folding. The data presented in this work strongly suggest that Pf DPY19 is unlikely to play a critical role in the asexual blood stages of the parasite, at least under in vitro conditions

«Et amicitia et magisterio»: Estudios en honor de José Manuel González Herrán

En este volumen se reúnen más de setenta estudios, ensayos y textos de creación escritos en honor de José Manuel González Herrán por colegas y amigos de España, Portugal, el Reino Unido, Francia, Suiza, Bélgica y Estados Unidos. La variedad de temas abordados se corresponde con las múltiples facetas investigadoras que ha cultivado el catedrático de la Universidad de Santiago de Compostela, destacado especialista en la literatura española de los siglos XVIII, XIX y XX y en las relaciones entre literatura y cin

Efectos del consumo digital en la Educación Latinoamericana

Las modificaciones precipitadas que atraviesa la sociedad en varios ámbitos de la productividad y la comunicación, obliga a que se adopten nuevos medios de transmisión de conocimientos por medio de la comunicación y el uso de la información a distancia.Por ende la transformación de la educación es un eje clave para que se desarrollen nuevas capacidades de creatividad e innovación, que se encaminen junto con la solidaridad y la integración a diferentes cambios. De tal motivo que en el área educativa no solo se impartan contenidos curriculares, sino que se genere un cambio significativo en cuanto a los procesos de aprendizaje, comunicación y producción de conocimientos.Es necesario mejorar la calidad de la educación, con el fin de que su papel se cumpla de manera efectiva dentro de la sociedad y hacia un orden global, competitivo que se centra en la sociedad de la información y del conocimiento. También es de gran valor el interactuar el desarrollo educativo con herramientas audiovisuales e interactivas, en donde cada vez se genera más participación del individuo.Por consiguiente, se ve la importancia de la interacción de la educación, la cultura y las nuevas tecnologí­as de la información y comunicación (TIC). El trabajar en la educación con las TIC, es generar nuevas formas de producir nuevos conocimientos, el comunicarse a distancia y formar parte de una era digital basada en el consumismo.

Viability of Glycolysis for the Chemical Recycling of Highly Coloured and Multi-Layered Actual PET Wastes

The chemical recycling of poly(ethylene terephthalate) –PET– fractions, derived from actual household packaging waste streams, using solvolysis, was investigated. This recycling strategy was applied after a previous on-line automatic identification, by near-infrared spectroscopy –NIR–, and a subsequent selective sorting of the different PET materials that were present in the packaging wastes. Using this technology, it was possible to classify fractions exclusively including PET, virtually avoiding the presence of both other plastics and materials, such as paper, cardboard and wood, that are present in the packaging wastes, as they were efficiently recognised and differentiated. The simple PET fractions, including clear and monolayered materials, were adequate to be recycled by mechanical means meanwhile the complex PET fractions, containing highly coloured and multi-layered materials, were suitable candidates to be recycled by chemical routes. The depolymerisation capacity of the catalytic glycolysis, when applied to those complex PET wastes, was studied by evaluating the effect of the process parameters on the resulting formation and recovery of the monomer bis(2-hydroxyethyl) terephthalate –BHET– and the achieved quality of this reaction product. Comparable and reasonable results, in terms of monomer yield and its characteristics, were obtained independently of the type of complex PET waste that was chemically recycled.This research was funded by the Department of Economic Development, Sustainability and Environment of The Basque Government by its ELKARTEK 2023 Program (NEOPLAST 2 Project, Reference KK-2023/00060), and also by CDTI (Centro para el Desarrollo Tecnológico Industrial), within the framework of grants for Technological Centres of Excellence “Cervera” (OSIRIS Project, CER-20211009)

The Apicomplexa-specific glucosamine-6-phosphate N-acetyltransferase gene family encodes a key enzyme for glycoconjugate synthesis with potential as therapeutic target

Apicomplexa form a phylum of obligate parasitic protozoa of great clinical and veterinary importance. These parasites synthesize glycoconjugates for their survival and infectivity, but the enzymatic steps required to generate the glycosylation precursors are not completely characterized. In particular, glucosamine-phosphate N-acetyltransferase (GNA1) activity, needed to produce the essential UDP-N-acetylglucosamine (UDP-GlcNAc) donor, has not been identified in any Apicomplexa. We scanned the genomes of Plasmodium falciparum and representatives from six additional main lineages of the phylum for proteins containing the Gcn5-related N-acetyltransferase (GNAT) domain. One family of GNAT-domain containing proteins, composed by a P. falciparum sequence and its six apicomplexan orthologs, rescued the growth of a yeast temperature-sensitive GNA1 mutant. Heterologous expression and in vitro assays confirmed the GNA1 enzymatic activity in all lineages. Sequence, phylogenetic and synteny analyses suggest an independent origin of the Apicomplexa-specific GNA1 family, parallel to the evolution of a different GNA1 family in other eukaryotes. The inability to disrupt an otherwise modifiable gene target suggests that the enzyme is essential for P. falciparum growth. The relevance of UDP-GlcNAc for parasite viability, together with the independent evolution and unique sequence features of Apicomplexa GNA1, highlights the potential of this enzyme as a selective therapeutic target against apicomplexans

Validation of the ‘Test of the Adherence to Inhalers’ (TAI) for Asthma and COPD Patients

Background: To validate the ‘Test of Adherence to Inhalers’ (TAI), a 12-item questionnaire designed to assess the adherence to inhalers in patients with COPD or asthma. Methods: A total of 1009 patients with asthma or COPD participated in a cross-sectional multicenter study. Patients with electronic adherence ≥80% were defined as adherents. Construct validity, internal validity, and criterion validity were evaluated. Self-reported adherence was compared with the Morisky-Green questionnaire. Results: Factor analysis study demonstrated two factors, factor 1 was coincident with TAI patient domain (items 1 to 10) and factor 2 with TAI health-care professional domain (items 11 and 12). The Cronbach's alpha was 0.860 and the test-retest reliability 0.883. TAI scores correlated with electronic adherence (ρ=0.293, p=0.01). According to the best cut-off for 10 items (score 50, area under the ROC curve 0.7), 569 (62.5%) patients were classified as non-adherents. The non-adherence behavior pattern was: erratic 527 (57.9%), deliberate 375 (41.2%), and unwitting 242 (26.6%) patients. As compared to Morisky-Green test, TAI showed better psychometric properties. Conclusions: The TAI is a reliable and homogeneous questionnaire to identify easily non-adherence and to classify from a clinical perspective the barriers related to the use of inhalers in asthma and COPD