DSpace Collection:
http://hdl.handle.net/10261/301
2024-03-19T02:07:20ZA new eyeless Poecilochroa Westring, 1874 (Araneae: Gnaphosidae) from Gran Canaria, Spain
http://hdl.handle.net/10261/350388
Título: A new eyeless Poecilochroa Westring, 1874 (Araneae: Gnaphosidae) from Gran Canaria, Spain
Autor: Lissner, Jørgen; Suárez, Daniel; López, Heriberto
Resumen: The mesovoid shallow substratum (MSS) of Gran Canaria is known to harbour a rich and diverse underground fauna. Since the 2000s surveys have been intensified in this island and the number of species associated with caves and MSS has steadily increased, now exceeding fifty species. In this study we describe another MSS species from Gran Canaria which is also the first eyeless member of the spider family Gnaphosidae from the Canary Islands. The new species is only tentatively placed in Poecilochroa Westring, 1874 and is named P. exoculata sp. nov.2024-03-14T09:13:40ZSensory attributes and quality perception of red natural wines: a comparative study in Spain and France
http://hdl.handle.net/10261/348755
Título: Sensory attributes and quality perception of red natural wines: a comparative study in Spain and France
Autor: Ballester, Jordi; Belascoin, Mirian; Gonzalez-Hernandez, Marivel; Parga-Dans, Eva; Alonso-González, Pablo; Sáenz-Navajas, María-Pilar
Resumen: Although the definition of natural wine remains contested and still lacks official recognition, it can be broadly described as a wine made with organic or biodynamic grapes without oenological additives in the cellar and minimal intervention in all winemaking stages. Despite growing interest in natural wines, uncertainty prevails about their sensory and quality attributes among both consumers and experts. In light of this research gap, this study aims to determine, first, if there are specific sensory dimensions allowing to differentiate natural wine as a wine category from conventional wines; second, if this sensory dimension affects the perception of the quality; and third, to characterise the physicochemical differences in terms of basic oenological parameters between natural wines and their conventional counterparts. To do so, 24 red wines (12 self-defined as natural and 12 conventional wines) were sensory and chemically characterised. The sensory evaluation was first carried out by winemakers from Spain. It consisted of a descriptive task (labelled sorting task) followed by a quality evaluation under two conditions: with and without information regarding the production method. A second panel of French experts carried out the same quality assessment, also with and without information. The aim was to find out whether expectations existed linked to each type of wine and to explore potential cross-cultural effects. The results of the labelled sorting task showed that natural wines tended to be different from conventional wines, but the difference was not clear-cut. However, natural wines were perceived to be of lower quality than their conventional counterparts, both with and without the information provided, regardless of the origin of winemakers. Results of the chemical analysis showed that natural wines presented higher values for volatile and total acidity and turbidity, while they had lower values for total and free sulphur. The study points to the existence of sensory dimensions with an impact on overall quality associated with the production method.2024-02-29T10:07:57ZAntioxidant Metabolism Pathways in Vitamins, Polyphenols, and Selenium: Parallels and Divergences
http://hdl.handle.net/10261/348737
Título: Antioxidant Metabolism Pathways in Vitamins, Polyphenols, and Selenium: Parallels and Divergences
Autor: Curieses Andrés, Celia María; Pérez de Lastra, José Manuel; Andrés Juan, Celia; Plou Gasca, Francisco José; Pérez-Lebeña, Eduardo
Resumen: Free radicals (FRs) are unstable molecules that cause reactive stress (RS), an imbalance between reactive oxygen and nitrogen species in the body and its ability to neutralize them. These species are generated by both internal and external factors and can damage cellular lipids, proteins, and DNA. Antioxidants prevent or slow down the oxidation process by interrupting the transfer of electrons between substances and reactive agents. This is particularly important at the cellular level because oxidation reactions lead to the formation of FR and contribute to various diseases. As we age, RS accumulates and leads to organ dysfunction and age-related disorders. Polyphenols; vitamins A, C, and E; and selenoproteins possess antioxidant properties and may have a role in preventing and treating certain human diseases associated with RS. In this review, we explore the current evidence on the potential benefits of dietary supplementation and investigate the intricate connection between SIRT1, a crucial regulator of aging and longevity; the transcription factor NRF2; and polyphenols, vitamins, and selenium. Finally, we discuss the positive effects of antioxidant molecules, such as reducing RS, and their potential in slowing down several diseases.2024-02-29T08:55:50ZThe active site of O-GlcNAc transferase imposes constraints on substrate sequence
http://hdl.handle.net/10261/347367
Título: The active site of O-GlcNAc transferase imposes constraints on substrate sequence
Autor: Pathak, Shalini; Jana Alonso Lorenzo; Schimpl, Marianne; Rafie, Karim; Blair, David E.; Borodkin, Vladimir S.; Schüttelkopf, Alexander W.; Albarbarawi, Osama; van Aalten, Daan M. F.
Resumen: O-GlcNAc transferase (OGT) glycosylates a diverse range of intracellular proteins with O-linked N-acetylglucosamine (O-GlcNAc), an essential and dynamic post-translational modification in metazoans. Although this enzyme modifies hundreds of proteins with O-GlcNAc, it is not understood how OGT achieves substrate specificity. In this study, we describe the application of a high-throughput OGT assay to a library of peptides. We mapped sites of O-GlcNAc modification by electron transfer dissociation MS and found that they correlate with previously detected O-GlcNAc sites. Crystal structures of four acceptor peptides in complex with Homo sapiens OGT suggest that a combination of size and conformational restriction defines sequence specificity in the −3 to +2 subsites. This work reveals that although the N-terminal TPR repeats of OGT may have roles in substrate recognition, the sequence restriction imposed by the peptide-binding site makes a substantial contribution to O-GlcNAc site specificity.2024-02-16T12:10:37Z