The Domains of Human Nutrition: The Importance of Nutrition Education in Academia and Medical Schools.

Human nutrition encompasses an extremely broad range of medical, social, commercial, and ethical domains and thus represents a wide, interdisciplinary scientific and cultural discipline. The high prevalence of both disease-related malnutrition and overweight/obesity represents an important risk factor for disease burden and mortality worldwide. It is the opinion of Federation of the Italian Nutrition Societies (FeSIN) that these two sides of the same coin, with their sociocultural background, are related to a low "nutritional culture" secondary, at least in part, to an insufficient academic training for health-care professionals (HCPs).

ATP independent proteasomal degradation of NQO1 in BL cell lines.

Human NAD(P)H: quinone oxidoreductase 1 (NQO1) catalyzes the obligatory two-electron reduction of quinones. For this peculiar catalytic mechanism, the enzyme is considered an important cytoprotector. The NQO1 gene is expressed in all human tissues, unless a polymorphism due to C609T point mutation is present.

The belonging of gpMuc, a glycoprotein from Mucuna pruriens seeds, to the Kunitz-type trypsin inhibitor family explains its direct anti-snake venom activity.

In Nigeria, Mucuna pruriens seeds are locally prescribed as an oral prophylactic for snake bite and it is claimed that when two seeds are swallowed they protect the individual for a year against snake bites. In order to understand the Mucuna pruriens antisnake properties, the proteins from the acqueous extract of seeds were purified by three chromatographic steps: ConA affinity chromatography, tandem anionic-cationic exchange and gel filtration, obtaining a fraction conventionally called gpMucB. This purified fraction was analysed by SDS-PAGE obtaining 3 bands with apparent masses ranging from 20 to 24 kDa, and by MALDI-TOF which showed two main peaks of 21 and 23 kDa and another small peak of 19 kDa.

High hydrostatic pressure-induced conformational changes in protein disulfide oxidoreductase from the hyperthermophilic archaeon Pyrococcus furiosus. A Fourier-transform infrared spectroscopic study.

Protein disulfide oxidoreductases (PDOs) are ubiquitous redox enzymes that catalyse dithiol-disulfide exchange reactions. PDOs have been well studied in bacteria and eukarya, and they have been described in a number of thermophilic and hyperthermophilic species, where they play a critical role in the structural stabilization of intracellular proteins. In this study, the effect of high hydrostatic pressure on the structural properties of PDO from the hyperthermophilic archaeon Pyrococcus furiosus (PfPDO) was analysed in order to gain insights on the possible mechanisms used to endure extreme environmental conditions.

Structure and stability of a rat odorant-binding protein: another brick in the wall.

The effect of temperature on the structure of the rat odorant-binding protein was investigated by spectroscopic and in silico methodologies. In particular, in this work, we examined the structural features of the rat OBP-1F by Fourier-transform infrared spectroscopy and molecular dynamics investigations. The obtained spectroscopic results were analyzed using the following three different methods based on the unexchanged amide hydrogens of the protein sample: (1) the analysis of difference spectra; (2) the generalized 2D-IR correlation spectroscopy; (3) the phase diagram method.

A strategic fluorescence labeling of D-galactose/D-glucose-binding protein from Escherichia coli helps to shed light on the protein structural stability and dynamics.

The D-glucose/D-galactose-binding protein (GGBP) of Escherichia coli serves as an initial component for both chemotaxis toward D-galactose and D-glucose and high-affinity active transport of the two sugars. GGBP is a monomer with a molecular weight of about 32 kDa that binds glucose with micromolar affinity. The sugar-binding site is located in the cleft between the two lobes of the bilobate protein.

A comparative infrared spectroscopic study of glycoside hydrolases from extremophilic archaea revealed different molecular mechanisms of adaptation to high temperatures.

The identification of the determinants of protein thermal stabilization is often pursued by comparing enzymes from hyperthermophiles with their mesophilic counterparts while direct structural comparisons among proteins and enzymes from hyperthermophiles are rather uncommon. Here, oligomeric beta-glycosidases from the hyperthermophilic archaea Sulfolobus solfataricus (Ss beta-gly), Thermosphaera aggregans (Ta beta-gly), and Pyrococcus furiosus (Pf beta-gly), have been compared. Studies of FTIR spectroscopy and kinetics of thermal inactivation showed that the three enzymes had similar secondary structure composition, but Ss beta-gly and Ta beta-gly (temperatures of melting 98.

Binding of glucose to the D-galactose/D-glucose-binding protein from Escherichia coli restores the native protein secondary structure and thermostability that are lost upon calcium depletion.

The effect of the depletion of calcium on the structure and thermal stability of the D-galactose/D-glucose-binding protein (GGBP) from Escherichia coli was studied by fluorescence spectroscopy and Fourier-transform infrared spectroscopy. The calcium-depleted protein (GGBP-Ca) was also studied in the presence of glucose (GGBP-Ca/Glc). The results show that calcium depletion has a small effect on the secondary structure of GGBP, and, in particular it affects a population of alpha-helices with a low exposure to solvent.

Oleoylethanolamide protects human sperm cells from oxidation stress: studies on cases of idiopathic infertility.

N-acylethanolamides are naturally occurring hydrophobic molecules usually present in a very small amount in many mammalian tissues and cells. The presence of N-acylethanolamides has also been demonstrated in human reproductive tracts and fluids, although their biological effects and molecular mechanisms of action are not yet completely elucidated. It is known that some N-acylethanolamides, such as oleoylethanolamide, have antioxidative properties.

Temperature-, SDS-, and pH-induced conformational changes in protein disulfide oxidoreductase from the archaeon Pyrococcus furiosus: a dynamic simulation and fourier transform infrared spectroscopic study.

The effect of SDS, pD, and temperature on the structure and stability of the protein disulfide oxidoreductase from Pyrococcus furiosus (PfPDO) was investigated by molecular dynamic (MD) simulations and FT-IR spectroscopy. pD affects the thermostability of alpha-helices and beta-sheets differently, and 0.5% or higher SDS concentration influences the structure significantly.

Temperature-induced molten globule-like state in human alpha1-acid glycoprotein: an infrared spectroscopic study.

Despite extensive investigations on thermal denaturation of alpha(1)-acid glycoprotein (AGP) using a variety of techniques, structural features of the folded-unfolded state in terms of residual secondary structures and the structural transitions involved in this process have not been fully characterized. In this study we employed FT-IR spectroscopy to investigate the thermal unfolding and reversibility of temperature-induced changes in AGP. The data revealed a fully reversible beta-sheet-rich protein which exhibits a molten globule-like state, an important protein folding intermediate.

Increased plasma concentrations of palmitoylethanolamide, an endogenous fatty acid amide, affect oxidative damage of human low-density lipoproteins: an in vitro study.

Fatty acid ethanolamides (NAEs) are naturally occurring hydrophobic molecules usually present in a very small amount in many mammalian tissues and cells. Moreover, these compounds have been isolated in mammalian biological fluids, such as blood. Palmitoylethanolamide (C16:0) (PEA) is a fully saturated NAE, which presents some possible pharmaceutical activities, such as anti-inflammatory and antinociceptive effects.

Idiopathic infertility: effect of palmitoylethanolamide (a homologue of anandamide) on hyperactivated sperm cell motility and Ca2+ influx.

The goal of this study was to examine the effect of palmitoylethanolamide (PEA) on the capacitation process and hyperactivated motility (HA) in idiopathic infertile men. Our data show the effect of PEA on the kinematic parameters of sperm cells from idiopathic infertile men during the capacitation of spermatozoa in vitro, both in the presence and absence of 2.5 nM PEA, a molecule physiologically present in human reproductive tracts.

Computational, spectroscopic, and resonant mirror biosensor analysis of the interaction of adrenodoxin with native and tryptophan-modified NADPH-adrenodoxin reductase.

In steroid hydroxylation system in adrenal cortex mitochondria, NADPH-adrenodoxin reductase (AR) and adrenodoxin (Adx) form a short electron-transport chain that transfers electrons from NADPH to cytochromes P-450 through FAD in AR and [2Fe-2S] cluster in Adx. The formation of [AR/Adx] complex is essential for the electron transfer mechanism in which previous studies suggested that AR tryptophan (Trp) residue(s) might be implicated. In this study, we modified AR Trps by N-bromosuccinimide (NBS) and studied AR binding to Adx by a resonant mirror biosensor.

Two-dimensional IR correlation spectroscopy of mutants of the beta-glycosidase from the hyperthermophilic archaeon Sulfolobus solfataricus identifies the mechanism of quaternary structure stabilization and unravels the sequence of thermal unfolding events.

Beta-glycosidase from the hyperthermophilic archaeon Sulfolobus solfataricus is a homotetramer with a higher number of ion pairs compared with mesophilic glycoside hydrolases. The ion pairs are arranged in large networks located mainly at the tetrameric interface of the molecule. In the present study, the structure and thermal stability of the wild-type beta-glycosidase and of three mutants in residues R488 and H489 involved in the C-terminal ionic network were examined by FTIR (Fourier-transform IR) spectroscopy.

Correlation between functional and structural changes of reduced and oxidized trout hemoglobins I and IV at different pHs. A circular dichroism study.

Circular dichroism (CD) spectra of two major hemoglobin components (Hb), HbI and HbIV, from Oncorhyncus mykiss (formerly Salmo irideus) trout were evaluated in the range 250-600 nm. HbI is characterized by a complete insensitivity to pH changes, while HbIV presents the Root effect. Both reduced [iron(II) or oxy] and oxidized (met) forms of the two proteins were studied at different pHs, 7.

Structural and thermal stability characterization of Escherichia coli D-galactose/D-glucose-binding protein.

The effect of temperature and glucose binding on the structure of the galactose/glucose-binding protein from Escherichia coli was investigated by circular dichroism, Fourier transform infrared spectroscopy, and steady-state and time-resolved fluorescence. The data showed that the glucose binding induces a moderate change of the secondary structure content of the protein and increases the protein thermal stability. The infrared spectroscopy data showed that some protein stretches, involved in alpha-helices and beta strand conformations, are particularly sensitive to temperature.

Thermal stability and aggregation of sulfolobus solfataricus beta-glycosidase are dependent upon the N-epsilon-methylation of specific lysyl residues: critical role of in vivo post-translational modifications.

Methylation in vivo is a post-translational modification observed in several organisms belonging to eucarya, bacteria, and archaea. Although important implications of this modification have been demonstrated in several eucaryotes, its biological role in hyperthermophilic archaea is far from being understood. The aim of this work is to clarify some effects of methylation on the properties of beta-glycosidase from Sulfolobus solfataricus, by a structural comparison between the native, methylated protein and its unmethylated counterpart, recombinantly expressed in Escherichia coli.

Effects induced by mono- and divalent cations on protein regions responsible for thermal adaptation in beta-glycosidase from Sulfolobus solfataricus.

The perturbation induced by mono- and divalent cations on the thermophilicity and thermostability of Solfolobus solfataricus beta-glycosidase, a hyperthermophilic tetrameric enzyme, has been investigated by spectroscopic and computational simulation methods to ascertain the Hofmeister effects on two strategic protein regions identified previously. Specifically, (1). an extra segment (83-124), present only in the sequence of hyperthermophilic glycosidases and recognized as an important thermostability determinant for the enzyme structure; and (2).

The N-terminal region of HtrA heat shock protease from Escherichia coli is essential for stabilization of HtrA primary structure and maintaining of its oligomeric structure.

HtrA heat shock protease is highly conserved in evolution, and in Escherichia coli, it protects the cell by degradation of proteins denatured by heat and oxidative stress, and also degrades misfolded proteins with reduced disulfide bonds. The mature, 48-kDa HtrA undergoes partial autocleavage with formation of two approximately 43 kDa truncated polypeptides. We showed that under reducing conditions, the HtrA level in cells was increased and efficient autocleavage occurred, while heat shock and oxidative shock caused the increase of HtrA level, but not the autocleavage.

Different modulation of phospholipase A2 activity by saturated and monounsaturated N-acylethanolamines.

The physiological functions of N-acylethanolamines (NAEs) are poorly understood, although many functions were suggested for these naturally occurring membrane components of plants and animals. The binding with cannabinoid receptors CB1 and CB2 was demonstrated for some NAEs, such as anandamide. However, the chemical nature of these molecules suggests that some of their biological effects on biomembranes could be related, at least partially, to physical interactions with the lipid bilayer.

Structure-activity relationship on fungal laccase from Rigidoporus lignosus: a Fourier-transform infrared spectroscopic study.

The structure and thermal stability of a laccase from Rigidoporus lignosus (Rl) was analysed by Fourier-transform infrared (FT-IR) spectroscopy. The enzyme was depleted of copper atoms, then part of the apoenzyme was re-metalled and these two forms of the protein were analysed as well. The enzymatic activity, lost by the removal of copper atoms, was restored in the re-metalled apoenzyme and resulted similar to that of native protein.

Specific methylation of the CpG-rich domains in the promoter of the human tissue transglutaminase gene.

The activity of tissue transglutaminase is present in many cells and tissues but almost absent in leucocytes and lymphocytes. The present work describes the distribution of 5-methylcytosine along the bisulphite-converted promoter of the human tissue transglutaminase gene as being in an essentially repressed state. In this promoter, the chain-specific sequencing revealed the location of three CpG-rich domains whose methylation responds to an 'all or nothing' signal.

Effect of acidic phospholipids on the structural properties of recombinant cytosolic human glyoxalase II.

A peculiar characteristic of highly concentrated cytosolic recombinant human glyoxalase II (GII) solutions is to undergo partial precipitation. Previous work indicated that anionic phospholipids (PLs) exert a noncompetitive inhibition on the enzymatic activity of the soluble enzyme. In this study, FTIR spectroscopy was used to analyze the structural properties and the thermal stability of the soluble protein in the absence and in the presence of liposomes made of different phospholipids (PLs).