13 research outputs found
Questions to objects/ Vragen aan objecten
No full textQuestions to objects/ Vragen aan objecten is a bilingual artist book written by Vlad Ionescu about the artistic research project of Nedda El-Asmar, professor at PXL MAD. School of Arts. Nedda El-Amsar is hereby recognised as co-author of the book. The book deals with the tranformative process of melting donated gold and turning it into a newly designed object.
https://www.borgerhoff-lamberigts.be/mer/shop/books/nedda-el-asmar-questions-to-objects-vragen-aan-objecte
Effects of elicitors and Ca2+ deprivation on the levels of sterols and 1alpha,25-dihydroxy vitamin D3 in cell cultures of Solanum malacoxylon
No full text1alpha,25-dihydroxy vitamin D-3[1alpha,25(OH)(2)D-3], the hormonal form of vitamin D-3 that is essential for the maintenance of calcium-phosphorus homeostasis in birds and mammals, has been found in several plants. In order to study the metabolic role of 1alpha,25(OH)(2)D-3 in plant cells, we monitored the changes of cellular levels of 1alpha,25(OH)(2)D-3 in cell suspension cultures of Solanum malacoxylon Sendt. under different experimental conditions. We also measured the levels of cholesterol, the assumed precursor of vitamin D-3, and other end-product sterols such as beta-sitosterol, stigmasterol and campesterol. It was found that when cells are incubated in a calcium-deprived medium, the level of 1alpha,25(OH)(2)D-3 increases markedly within a few hours. Treatment with methyl jasmonate (MeJ), a linolenic acid-derived compound that accumulates during wounding stress, was found to reduce the cellular level of 1alpha,25(OH)(2)D-3 and to promote its secretion into the culture medium. After treatment with cellulysin, a cellulase of fungal origin, the metabolite was no longer detectable, either in the medium or in the cells. Calcium deprivation in the medium and treatment with the elicitors MeJ and cellulase lowered the cellular level of all the sterols tested. The possible role of 1alpha,25(OH)(2)D-3 is discussed in light of these results
Identification of enzyme activities involved in vitamin D3 metabolism in Solanum malacoxylon
No full textIn animals vitamin D3 is made from 7-deydrocholesterol through the action of UV light in the skin; the activation process of vitamin D3 involves a 25-hydroxylation in the liver, followed by a 1a-hydroxylation in the kidney, leading to 1a,25(OH)2D3, the hormone active on the regulation of calcium homeostasis. Vitamin D3 and the related hydroxylated metabolites, 25-hydroxy vitamin D3 [25-OH D3] and 1a,25-dihydroxy vitamin D3 or calcitriol [1a,25-(OH)2D3], have been found also in different plants[1]. The physiological role of these substances in plants has not been clarified yet but different hypothesis have been considered [2].
Aburjai et al. [3] observed that when calli of Solanum malacoxylon were grown in the light, vitamin D3 and the related hydroxylated metabolites were identified; if the calli were grown in the dark, only 7-dehydrocholesterol was found: these findings suggest that in plant cells may be present a biosynthetic pathway for 1a,25-(OH)2D3 similar to the one acting in animals.
To confirm this hypothesis we attempted to identify the enzymes involved in vitamin D3 metabolism in plant. We detected a 25(OH) vitamin D3 1α-hydroxylase activity in mitochondrial membranes purified both from leaves and from cell cultures of Solanum malacoxylon.
An activity vitamin D3 25-hydroxylase has also been measured in a reconstituted system containing: a solubilized enzyme fraction obtained from a cell cultures microsomal preparation, NADPH, ferredoxin-NADP+ reductase and ferredoxin I, both recombinant proteins from spinach. An attempt to identify also a 24-hydroxylase, the enzyme responsible for 25-OH D3 and 1a,25-(OH)2D3 catabolism in animals, is in progress
Interpretation of female representatives of verismo ( Santuzza, Nedda)
No full textThe work deals with the interpretation of two female representatives of verismo operas. These are Santuzza ( Pietro Mascagni: Cavalleria rusticana) and Nedda ( Ruggiero Leoncavallo : Pagliacci). Interpretation of both roles is based on author´s personal experience and focuses on selected Czech and Slovak singers, which the author saw personally on stage or on videos of Czech theaters and Slovak National Theatre. The work also includes basic information about the composers of both operas and analysis of selected arias
Benzothiadiazole (BTH) activates sterol pathway and affects vitamin D3 metabolism in Solanum malacoxylon cell cultures
No full textBenzo-(1,2,3)-thiadiazole-7-carbothioic acid S-methyl ester (BTH), a particularly efficient inducer of systemic acquired resistance (SAR), was developed as an immunizing agent to sensitize various crop species against pathogen infections. Recent works highlighted its activating effect on different metabolic pathways, concerning both primary and secondary metabolites. In this study, we investigated the effect of BTH treatment on sterol levels and vitamin D-3 metabolism in Solanum malacoxylon cultures. Calli of S. malacoxylon were incubated in Gamborg B5 liquid medium alone or added with 50 mu M BTH for different times (one, two or three cycles of light). Histocytochemical investigations performed on our experimental system using 3,3'-diaminobenzidine (DAB) for hydrogen peroxide (H2O2) detection and phloroglucinol for lignin staining showed that BTH causes H2O2 accumulation and lignin deposition in treated calli. Gas chromatographic analysis of principal cell membrane sterols (beta-sitosterol, campesterol, stigmasterol) showed that BTH transiently increases their cellular levels. Callus cultures were found to contain also cholesterol, 7-dehydrocholesterol, the putative precursor of vitamin D-3, and the hydroxylated metabolites 25-hydroxyvitamin D-3 [25(OH)D-3] and 1 alpha,25-dihydroxyvitamin D-3 [1 alpha,25(OH)(2)D-3]. BTH treatment enhanced 7-dehydrocholesterol while reduced cholesterol. HPLC analysis of sample extracts showed that BTH does not affect the cell content of vitamin D3, though results of ELISA tests highlighted that this elicitor moderately enhances the levels of 25(OH)D-3 and 1 alpha,25(OH)(2)D-3 metabolites. In conclusion, BTH treatment not only causes cell wall strengthening, a typical plant defence response, as just described in other experimental models, but in the same time increases the cellular level of the main sterols and 7-dehydrocholesterol
Dependence on cyclic AMP of glucose-induced inactivation of yeast gluconeogenetic enzymes
No full textDe la violence dans quelques nouvelles de Verga
No full textInternational audienceGiovanni Verga was a man of his time. He believed in progress and thought that evolution entailed the elimination of those who were unfit to economic change. The author of this article analyses three short stories whose main characters are the victims of social violence. Because Nedda is the only daughter of a poor and sick widow she is doomed to destitution, celibacy and dishonour when she gets pregnant. Rosso Malpelo is a child who works in a quarry and after his father’s death is bullied by his fellow workers while he himself victimizes a sick lame boy who works under his supervision. In La libertà Verga relates the revolt of the peasants of Bronte and the ensuing repression by Garibaldi’s deputy Nino Bixio and his troops. However, the article focuses on how Verga compels his readers to face violence. In Nedda the narrator has compassion for the “poor girl’s fate” and so have the readers. This means that the harshness of Nedda’s plight is softened and partly concealed by the sympathy her condition arouses in the readers. In Rosso Malpelo on the contrary the narrator (as demonstrated by Romano Luperini) thinks that physical abuse is a natural feature of social life. Consequently the readers must dissociate themselves from the narrator in order to protect themselves from the violence reported in the text. In La libertà, there is no mediation between the gruesome sight of the peasants’ cruelty or, later, the ferocity of the armed forces, and the reader. Hence the latter’s inability to take sides either with the rioting masses or those who carried out the repression.Giovanni Verga était un homme de son époque. Il croyait au progrès et pensait que l’évolution entraînait l’élimination de ceux qui ne pouvaient pas s’adapter au changement. L’auteur de l’article analyse trois nouvelles dont les protagonistes sont des victimes de la violence sociale. Étant la fille unique d’une veuve pauvre et malade, Nedda est destinée à la misère, au célibat et au déshonneur quand elle est enceinte. Rosso Malpelo est un enfant qui travaille dans une carrière et, après la mort de son père, est brutalisé par les autres ouvriers alors que lui-même martyrise un garçon boiteux et malade qui travaille à ses côtés. Dans La liberté, Verga relate la révolte des paysans de Bronte et la répression qui s’ensuivit menée par Nino Bixio pour le compte de Garibaldi. Cependant l’article étudie surtout la façon dont Verga place ses lecteurs face à la violence. Dans Nedda le narrateur a de la pitié pour le destin de celle qu’il désigne comme ‘une pauvre enfant’, apitoyant ainsi ses lecteurs. Cela signifie que la dureté de la condition de Nedda est contrebalancée et en partie masquée par la sympathie que sa misère suscite chez les lecteurs. Dans Rosso Malpelo en revanche (comme cela a été montré par Romano Luperini), le narrateur estime que mauvais traitements et sévices sont une donnée parfaitement naturelle de la vie en société. Aussi les lecteurs doivent-ils se dissocier du narrateur pour se protéger de la violence qui se dégage du texte. Dans La libertà, il n’y aucune médiation entre la cruauté des paysans puis celle de l’armée et le lecteur, de ce fait, est dans l’impossibilité de prendre parti que ce soit pour les émeutiers ou ceux qui organisent la répression
Author Correction: Improved reference genome for the domestic horse increases assembly contiguity and composition
No full textAuthor Correction: Puma genomes from North and South America provide insights into the genomic consequences of inbreeding
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