1,721,096 research outputs found
Combining voltammetric and mass spectrometric data to evaluate iron organic speciation in subsurface coastal seawater samples of the Ross sea (Antarctica)
No full textIron (Fe) is the most important trace element in the ocean, as it is required by phytoplankton for photosynthesis and nitrate assimilation. Iron speciation is important to better understand the biogeochemical cycle and availability of this micronutrient, in particular in the Southern Ocean. Dissolved Fe (dFe) concentration and speciation were determined in 24 coastal subsurface seawater samples collected in the western Ross sea (Antarctica) during the austral summer 2017 as part of the CELEBeR (CDW Effects on glacial mElting and on Bulk of Fe in the Western Ross sea) project. ICP-DRC-MS was used for dFe determination, whereas CLE-AdSV was used to obtain the concentration of complexed and free dFe, of the ligands, and the values of the stability constants of the complexes. Dissolved Fe values ranged from 0.4 to 2.5 nM and conditional stability constant (logK'Fe'L) from 13.0 to 15.0, highlighting the presence of Fe-binding organic complexes of different stabilities. Principal component analysis (PCA) allowed us to point out that Terra Nova Bay and the neighboring area of Aviator and Mariner Glaciers were different in terms of chemical, physical, and biological parameters. A qualitative investigation on the nature of the organic ligands was carried out by HPLC-ESI-MS/MS. Results showed that siderophores represented a heterogeneous class of organic ligands pool
Positive patch test reactionto Lonicera japonica extract in a patient sensitized to formaldehyde
No full textYeast strain expressing C. reniformis prolyl hydroxylase for recombinant marine collagen production
No full textThere is an increasing demand for alternative sources of collagens, which are needed for a wide variety of applications (food, cosmetics, healthcare). Sponge collagens have unique physico-chemical properties and as a consequence are a promising resource, but sponge collagens are not available in large quantities. A biotechnology-based approach for a sustainable production of this family of proteins is here shown. The expression system consists of a yeast strain co-transformed with three different expression vectors containing the following coding sequences identified and cloned from Chondrosia reniformis marine sponge: i) the alpha subunit of C. reniformis enzyme prolyl-4-hydroxylase (P4H), equipped with its signal peptide for endoplasmic reticulum localization, ii) the coding sequence of the beta subunit of the same enzyme (Protein disulphite Isomerase, PDI) whose signal peptide has been replaced with that of S. cerevisiae AlfaMating factor (AM) ensuring a better solubility and activity of the quaternary structure of the reconstituted enzyme in the yeast, and iii) the coding sequence of a non-fibrillar collagen from C. reniformis resembling, from homology sequence analysis, mammalian collagen type IV. The yeast strain used is defective for a gene related to the synthesis of adenine (ade2), while the first vector, carrying the P4H sequence, contains the ADE2 gene allowing the transformed yeast to grow on a medium lacking the purine . In turn, the other two expression vectors are equipped with markers for antibiotic resistance such as blasticidin and zeocin for the PDI expression vector and the collagen expression vector, respectively. Co-transformed yeast strains were finally isolated and cloned in plates containing a semi-solid medium lacking adenine and in the presence of both antibiotics. The enzymatic activity of P4H was then assessed by a specific assay on the microsomal fraction of the co-transformed strain. Presence of the recombinant collagen was subsequently confirmed both in the yeast extract and in the cell culture medium. In particular protein expression was assessed by mass spectrometry analysis of triptic peptides derived from digestion of a protein extracted from SDS-PAGE gel with a molecular weight corresponding to that of C. reniformis collagen single chain and found specifically only in the tripletransformed yeast strain
High throughput HPLC-ESI-MS method for the quantitation of dexamethasone in blood plasma.
No full textPositive patch test reaction to Lonicera japonica extract in a patient sensitized to formaldehyde
No full textElectrophysiological study of the effects of side products of RuBi-GABA uncaging on GABAA receptors in cerebellar granule cells
No full textThe study of the GABAA receptor itself and its pharmacology is of paramount importance for shedding light on the role of this receptor in the central nervous system. Caged compounds have emerged as powerful tools to support research in this field, as they allow to control, in space and time, the release of neurotransmitters enabling, for example, to map receptors' distribution and dynamics. Here we focus on γ-aminobutyric acid (GABA)-caged compounds, particularly on a commercial complex called RuBi-GABA, which has high efficiency of uncaging upon irradiation at visible wavelengths. We characterized, by electrophysiological measurements, the effects of RuBi-GABA on GABAA receptors of rat cerebellar granule cells in vitro. In particular, we evaluated the effects of side products obtained after RuBi-GABA photolysis. For this purpose, we developed a procedure to separate the "RuBi-cage" from GABA after uncaging RuBi-GABA with a laser source; then, we compared electrophysiological measurements acquired with and without administering the RuBi-cage in the perfusing bath. In conclusion, to investigate the role of the "cage" molecules both near and far from the cell soma, we compared experiments performed changing the distance of the uncaging point from the cell
Metodo per la produzione di collagene marino ricombinante e organismo capace di produrre detto collagene marino
No full textMetodo per la produzione di proteine collageniche ricombinanti di spugna di mare il quale metodo prevede l’introduzione e l’espressione all’interno di un organismo ospite di almeno una sequenza nucleotidica codificante per una catena polipetidica primaria di collagene marino, cosiddetto procollagene, e di almeno una sequenza nucleotidica codificante per una proteina enzimatica o di almeno una sua subunità coinvolta nelle modifiche di detta catena nel processo di formazione del collagene marino
- …
