Search results for "wolf"

Progress on nuclear reaction rates affecting the stellar production of 26Al

2023

Abstract The radioisotope 26Al is a key observable for nucleosynthesis in the Galaxy and the environment of the early Solar System. To properly interpret the large variety of astronomical and meteoritic data, it is crucial to understand both the nuclear reactions involved in the production of 26Al in the relevant stellar sites and the physics of such sites. These range from the winds of low- and intermediate-mass asymptotic giant branch stars; to massive and very massive stars, both their Wolf–Rayet winds and their final core-collapse supernovae (CCSN); and the ejecta from novae, the explosions that occur on the surface of a white dwarf accreting material from a stellar companion. Several r…

Vinorine synthase from Rauvolfia: the first example of crystallization and preliminary X-ray diffraction analysis of an enzyme of the BAHD superfamily

2004

Abstract Crystals of vinorine synthase (VS) from medicinal plant Rauvolfia serpentina expressed in Escherichia coli have been obtained by the hanging-drop technique at 305 K with ammonium sulfate and PEG 400 as precipitants. The enzyme is involved in the biosynthesis of the antiarrhythmic drug ajmaline and is a member of the BAHD superfamily of acyltransferases. So far, no three-dimensional structure of a member of this enzyme family is known. The crystals belong to the space group P 2 1 2 1 2 1 with cell dimensions of a =82.3 A, b =89.6 A and c =136.2 A. Under cryoconditions (120 K), a complete data set up to 2.8 A was collected at a synchrotron source.

Heterologous expression, purification, crystallization and preliminary X-ray analysis of raucaffricine glucosidase, a plant enzyme specifically invol…

2006

Raucaffricine glucosidase (RG) is an enzyme that is specifically involved in the biosynthesis of indole alkaloids from the plant Rauvolfia serpentina. After heterologous expression in Escherichia coli cells, crystals of RG were obtained by the hanging-drop vapour-diffusion technique at 293 K with 0.3 M ammonium sulfate, 0.1 M sodium acetate pH 4.6 buffer and 11% PEG 4000 as precipitant. Crystals belong to space group I222 and diffract to 2.30 A, with unit-cell parameters a = 102.8, b = 127.3, c = 215.8 A.

Hydroquinone: O-glucosyltransferase from cultivated Rauvolfia cells: enrichment and partial amino acid sequences.

2000

Plant cell suspension cultures of Rauvolfia are able to produce a high amount of arbutin by glucosylation of exogenously added hydroquinone. A four step purification procedure using anion exchange, hydrophobic interaction, hydroxyapatite-chromatography and chromatofocusing delivered in a yield of 0.5%, an approximately 390 fold enrichment of the involved glucosyltransferase. SDS-PAGE showed a M(r) for the enzyme of 52 kDa. Proteolysis of the pure enzyme with endoproteinase LysC revealed six peptide fragments with 9-23 amino acids which were sequenced. Sequence alignment of the six peptides showed high homologies to glycosyltransferases from other higher plants.

Crystallization and preliminary X-ray crystallographic analysis of strictosidine synthase from Rauvolfia: the first member of a novel enzyme family.

2004

Strictosidine synthase is a central enzyme involved in the biosynthesis of almost all plant monoterpenoid indole alkaloids. Strictosidine synthase from Rauvolfia serpentina was heterologously expressed in Escherichia coli. Crystals of the purified recombinant enzyme have been obtained by the hanging-drop technique at 303 K with potassium sodium tartrate tetrahydrate as precipitant. The crystals belong to the space group R3 with cell dimensions of a=b=150.3 A and c=122.4 A. Under cryoconditions (120 K), the crystals diffract to about 2.95 A.

Contradicciones del marxismo

2018

Indicatori di Wolff per la valutazione del rischio clinico: Fase preliminare presso il Presidio Ospedaliero "Sant'Antonio Abate" di Trapani.

2010

Purification and partial amino acid sequences of the enzyme vinorine synthase involved in a crucial step of ajmaline biosynthesis.

2004

The acetyl-CoA-dependent enzyme vinorine synthase was isolated from hybrid cell suspension cultures of Rauvolfia serpentina and Rhazya stricta. The sarpagan-type alkaloid gardneral was used as a substrate of the enzyme leading to the ajmalan-type 10-methoxyvinorine. An HPLC-based assay was developed to monitor vinorine synthase activity, which allowed establishing a five step purification procedure combining anion exchange, hydrophobic interaction, hydroxyapatite and gel filtration. Purification resulted in a yield of 0.2% and an approximately 991-fold enrichment of the acetyltransfer activity. SDS-PAGE analysis showed a Mr for the enzyme of approximately 50 kDa. The four peptide fragments …

Memoria, disinganno, composizione: Goethe, Kniep e la funzione del disegno durante il viaggio in Sicilia

2018

This article focuses on Goethe’s specific concept of drawing as it appears to the reader through the pages of his Italian journey. A fundamental role is played in this discourse by Christoph Heinrich Kniep, a young German draughtsman who has been recommended to Goethe by his friend, the painter Tischbein, and who accompanied the poet during his trip to Sicily. The key function of Kniep’s linear drawings was to create a visual archive destined to keep memory of his experience for future times, free from picturesque effects and potentially capable to force the recipient’s imagination. The relationship between the two travellers turned into a kind of creative symbiosis as can be seen from Goet…

«Una vera e non museografica conversazione di monumenti e di ambienti»: Guido Di Stefano e l’«azione urbanistica» nella Palermo del secondo dopoguerra

2019

L' articolo indaga gli scritti, le attività didattiche e le reti culturali dell'arte e dell'architettura siciliana storico Guido Di Stefano (1906-62). Concentrandosi sui suoi viaggi in Germania e sui suoi contatti con colleghi austriaci (Dagobert Frey), tedeschi (Wolfgang Krönig) ed eminenti colleghi italiani (Carlo Ludovico Ragghianti), l'autore legge la battaglia solitaria di Di Stefano contro la speculazione e il vandalismo nel settore immobiliare a Palermo, nonché il suo coinvolgimento nel stesura del piano urbano dopo la seconda guerra mondiale come aspetti specifici di un'idea di civiltà e impegno politico le cui radici possono essere identificate nell'influente pensiero filosofico di…