Search results for " Vita"

The Light-Harvesting Chlorophyll a/b Complex Can Be Reconstituted in Vitro from Its Completely Unfolded Apoprotein

2003

The major light-harvesting chlorophyll a/b protein (LHCIIb) of higher plants is one of the few membrane proteins that can be refolded in vitro. During folding, the apoprotein is assembled with pigments to form a structurally authentic and functional pigment--protein complex. All reconstitution procedures used so far include solubilization of the apoprotein in sodium dodecyl sulfate (SDS) where the protein adopts approximately half of its alpha-helical folding present in the native structure. This paper shows that this preformed alpha-helix is not a prerequisite for LHCIIb folding in vitro. The apoprotein can also be reconstituted starting from a solution in guanidinium hydrochloride (Gnd) w…

Simultaneous Determination of Pyridoxine and Riboflavin in Energy Drinks by High-Performance Liquid Chromatography with Fluorescence Detection

2015

Energy drinks, as familiar consumer products, have been widely used in laboratory courses to help promote student interest, as well as to connect lecture concepts with laboratory work. Energy drinks contain B vitamins: pyridoxine (vitamin B6) and riboflavin (vitamin B2) of which amounts are high enough to be of concern. In this work, a fast and inexpensive high-performance liquid chromatography (HPLC) coupled with fluorescence detection method for determining pyridoxine and riboflavin simultaneously in energy drinks is developed. It takes advantage of the native fluorescence of B vitamins and provides high selectivity and sensitivity with low background noise. The method is suitable for und…

Silica Entrapment for Significantly Stabilized, Energy-Conducting Light-Harvesting Complex (LHCII)

2014

The major light-harvesting chlorophyll a/b complex (LHCII) of the photosynthetic apparatus in green plants consists of a membrane protein and numerous noncovalently bound pigments that make up about one-third of the molecular mass of the pigment-protein complex. Due to this high pigment density, LHCII is potentially interesting as a light-harvesting component in synthetic constructs. However, for such applications its stability needs to be significantly improved. In this work, LHCII was dramatically stabilized by enclosing it within polymerizing colloidal silica. The entrapped LHCII stayed functional at 50 °C for up to 24 h instead of a few minutes in detergent solution and clearly showed e…

Determination of water-soluble vitamins in energy and sport drinks by micellar electrokinetic capillary chromatography

2016

Abstract A method for the determination of water-soluble vitamins in several energy and sport drinks by micellar electrokinetic chromatography (MEKC) has been developed in this work. The separation of vitamins was studied in terms of background electrolyte composition (borate content, pH, surfactant type and content) and in other MEKC parameters. A study of the possible compounds found in the vitamin-enriched drinks that could interfere in vitamin determination was also performed, and a modified procedure with enhanced resolution was developed. The proposed method was successfully applied to the analysis of water-soluble vitamins in a variety of energy and sport drinks and also in fruit nec…

Le relazioni tra le fasi della vita del prodotto e gli assetti strategici e strutturali delle imprese

2013

La scelta della disciplina applicabile ai c.dd. "vitalizi impropri". Riflessioni in tema di aleatorietà della rendita vitalizia e di tipicità e atipi…

2015

The essay stems from the current efforts in defining the rules applicable to the alleged 'vitalizi impropri'. The aims are to distance from dogmas and conceptual classifications that are blind to the concrete interests at stake and, as consequence, to debunk some common fallacies (i.e., the utility of traditional theories about mixed contracts; the idea of fungibility, periodicity and hazard as essential parts of typical life annuity).

Thermal stability of trimeric light-harvesting chlorophyll a/b complex (LHCIIb) in liposomes of thylakoid lipids.

2006

The major light-harvesting chlorophyll a/b complex (LHCIIb) of photosystem (PS) II functions by harvesting light energy and by limiting and balancing the energy flow directed towards the PSI and PSII reaction centers. The complex is predominantly trimeric; however, the monomeric form may play a role in one or several of the regulatory functions of LHCIIb. In this work the dissociation temperature was measured of trimeric LHCIIb isolated from Pisum thylakoids and inserted into liposomes made of various combinations of thylakoid lipids at various protein densities. Dissociation was measured by monitoring a trimer-specific circular dichroism signal in the visible range. The LHCIIb density in t…

Ascorbic acid content and transcriptional profiling of genes involved in its metabolism during development of petals, leaves, and fruits of orange (C…

2021

Citrus fruit is one of the most important contributors to the ascorbic acid (AsA) intake in humans. Here, we report a comparative analysis of AsA content and transcriptional changes of genes related to its metabolism during development of petals, leaves and fruits of Valencia Late oranges (Citrus sinensis). Petals of close flowers and at anthesis contained the highest concentration of AsA. In fruits, AsA content in the flavedo reached a maximum at color break, whereas the pulp accumulated lower levels and experienced minor fluctuations during development. AsA levels in leaves were similar to those in the flavedo at breaker stage. The transcriptional profiling of AsA biosynthetic, degradatio…

La dimensione urbana dell'immigrazione

2006

Life of Krembegi according to Pierre Clastres

2010

Nell'articolo si analizza un capitolo centrale dell'opera Chronique des Indiens Guayaki di Pierre Clastres. L'analisi della storia di vita illustrata nel testo mostra come l'autore adotti stilemi tipici del romanzo poliziesco per raccontare in forma narrativa la sua ipotesi interpretativa sulla struttura sociale dei Guayaki.