Gastrin stimulation of salivary secretion: preliminary observations

The authors have investigated the effect of pentagastrin and of meat extract on salivary secretion. Both stimuli significantly increase the secretion of saliva. Factors such as taste and deglutition don't influence the increase of salivary secretion due to meat extract, as it remains even when meat extract was administered by naso-gastric tube. This finding suggest that endogenous gastrin, stimulated by meat extract, as well as exogenous pentagastrin, influence the secretion of saliva.     

Protocatechuic acid induces antioxidant/detoxifying enzyme expression through JNK-mediated Nrf2 activation in murine macrophages

Protocatechuic acid (PCA) is a main metabolite of anthocyanins, whose daily intake is much higher than that of other polyphenols. PCA has biological effects, e.g., it induces the antioxidant/detoxifying enzyme gene expression. This study was aimed at defining the molecular mechanism responsible for PCA-induced over-expression of glutathione (GSH) peroxidase (GPx) and GSH reductase (GR) in J774 A.1 macrophages. New evidence is provided that PCA increases GPx and GR expression by inducing C-JUN NH₂-terminal kinase (JNK)-mediated phosphorylation of Nuclear factor erythroid 2 (NF-E2)-related factor 2 (Nrf2). RNA and proteins were extracted from cells treated with PCA (25 μM) for different time points. Quantitative real-time polymerase chain reaction and immunoblotting analyses showed a rapid increase in mRNA (>60%) and protein (>50%) for both the enzymes. This was preceded by the up-regulation of Nrf2, in terms of mRNA and protein, and by its significant activation as assessed by increased Nrf2 phosphorylation and nuclear translocation (+60%). By using specific kinase inhibitors and detecting the activated form, we showed that JNK was the main upstream kinase responsible for Nrf2 activation. Convincing evidence is provided of a causal link between PCA-induced Nrf2 activation and increased enzyme expression. By silencing Nrf2 and using a JNK inhibitor, enzyme enhancement was counteracted. Finally, with the ChIP assay, we demonstrated that PCA-activated Nrf2 specifically bound ARE sequences in enzyme gene promoters. Our study demonstrates for the first time that PCA improves the macrophage endogenous antioxidant potential by a mechanism in which JNK-mediated Nrf2 activation plays an essential role. This knowledge could contribute to novel diet-based approaches aimed at counteracting oxidative injury by reinforcing endogenous defences.     

Polyproline helices in protein structures: A statistical survey

A statistical survey of polyproline II (PPII) helices extracted from protein crystal structures is here reported. The average hydrophobicity of these helices is intermediate between those displayed by beta-strands and coil regions and is similar to that of alpha-helices. PPII helices with amphipathic properties have been identified and classified. Amino acid propensities for PPII helices derived in this study differ significantly from those previously reported. They show a little albeit significant correlation with propensities for alpha-helices whereas they are fully non-correlated to propensities for beta-sheets. Finally, PPII propensities have been correlated with amino acid frequencies in structural proteins, such as collagen and extensins.     

Microcapillary-like structures prompted by phospholipase A2 activation in endothelial cells and pericytes co-cultures on a polyhydroxymethylsiloxane thin film

A thin film of poly(hydroxymethylsiloxane) (PHMS) has been deposited on glass dishes and tested as artificial support material for vascularization from mixed cultures of endothelial cells (EC) and pericytes (PC). The EC/PC co-cultures adhered massively on PHMS, with the formation of net-like microcapillary structures. Such evidence was not found on control glass substrates in the same co-culture conditions neither on PHMS for EC and PC in monocultures. The physicochemical characterization of PHMS and control glass surface by time-of-flight secondary ion mass spectrometry, X-ray photoelectron spectroscopy, water contact angle and atomic force microscopy, pointed to the main role of the polymer hydrophobilicy to explain the observed cellular behavior. Moreover, enhanced intercellular cross-talk was evidenced by the up-regulation and activation of cytoplasmic and Ca(2+)-independent phospholipase A(2) (cPLA(2) and iPLA(2)) expression and cPLA(2) phosphorylation, leading to the cell proliferation and microcapillary formation on the PHMS surface, as evidenced by confocal microscopy analyses. Co-cultures, established with growth-arrested PCs by treatment with mitomycin C, showed an increase in EC proliferation on PHMS. AACOCF(3) or co-transfection with cPLA(2) and iPLA(2)siRNA reduced cell proliferation. The results highlight the major role played by EC/PC cross-talk as well as the hydrophobic character of the substrate surface, to promote microcapillary formation. Our findings suggest an attractive strategy for vascular tissue engineering and provide new details on the interplay of artificial substrates and capillary formation.     

The role of gut hormones in controlling the food intake. What is their role in emerging diseases?

Central nervous system (CNS) receives peripheral relevant information that are able to regulate individual's energy balance through metabolic, neural, and endocrine signals. Ingested nutrients come into contact with multiple sites in the gastrointestinal tract that have the potential to alter peptide and neural signaling. There is a strong relationship between CNS and those peripheral signals (as gastrointestinal hormones) in the control of food intake. The purpose of this review is to give updated information about the role of gut hormones as mediators of feeding behavior and of different nutrients in modulating gut hormones production. The role of gut hormones in the pathogenesis of emerging diseases as obesity and non-alcoholic fatty liver disease (NAFLD) is also discussed together with the possible role of these peripheral signals as targets of future therapeutic options.     

Prediction of potential barcoding sites on ITS1 by wavelet transform

For sustainable development, biodiversity conservation and life-quality improvement must be simultaneously considered. Molecular techniques have greatly impacted biotechnology. These methods have, in particular, improved the capability to investigate the fine differences among organisms and, as a consequence, to better investigate the effects on environmental factors on them. We propose an approach to support the optimal selection of molecular probes for barcoding application in many biotechnological fields. The aim of our work is specificity maximization. To this purpose, we have integrated a filter system based on wavelet transforms with biological knowledge about the sequence proneness to mutation and post-translational modification. Specifically, we have tested the proposed method on ITS1 sequences that are a region of the rRNA locus. Our analysis has shown the presence of other local relative stable conformations in addition to known cleavage site. Their characteristics differ within the group of mammals selected for our analysis. These variations could be used to design new species-specific barcoding probes or other quick molecular screening tools.     

Multilayered Polyelectrolyte Microcapsules: Interaction with the Enzyme Cytochrome C Oxidase

Cell-sized polyelectrolyte capsules functionalized with a redox-driven proton pump protein were assembled for the first time. The interaction of polyelectrolyte microcapsules, fabricated by electrostatic layer-by-layer assembly, with cytochrome c oxidase molecules was investigated. We found that the cytochrome c oxidase retained its functionality, that the functionalized microcapsules interacting with cytochrome c oxidase were permeable and that the permeability characteristics of the microcapsule shell depend on the shell components. This work provides a significant input towards the fabrication of an integrated device made of biological components and based on specific biomolecular functions and properties.     

Activation of cytosolic phospholipase A2 and 15-lipoxygenase by oxidized low-density lipoproteins in cultured human lung fibroblasts

In cell cultures of human lung fibroblasts, we found that oxidized LDL (oxLDL), after 24-h treatment, stimulated arachidonic acid release. A putative role for phospholipases A(2) and MAPK activities in this process was postulated. Consequently, we studied the contribution of either Ca(2+)-dependent, cytosolic phospholipase A(2) (cPLA(2)) or Ca(2+)-independent phospholipase A(2) (iPLA(2)), and the role of the MAP kinase family in oxLDL toxicity to fibroblastic cells in vitro. Activation of extracellular signal-regulated kinases ERK1/2, p38 and c-Jun NH(2)-terminal kinase (JNK) was also assessed with Western blotting. Compared with cellular samples untreated or treated with native LDL, treatment with oxLDL (50-100 microM hydroperoxides) for 24 h significantly increased the levels of either cPLA(2) protein expression or constitutively phosphorylated cPLA(2) protein; in addition we observed enzyme translocation to membranes. iPLA(2) activity was not stimulated by oxLDL. Arachidonic acid release appeared to be associated with phosphorylation of ERK1/2 which was significantly enhanced in a dose-dependent manner whereas no activation of p38 and JNKs was found, indicating that these MAPKs are not involved in mediating the maximal oxLDL response. Western blotting on subcellular fractions and confocal microscopy analyses confirmed an increase in 15-lipoxygenase (15-LO) protein expression and translocation upon activation. A significant increase of cyclooxygenase-2 expression into membrane fraction was also found. Collectively, the data presented link the stimulation of ERK-cPLA(2)-15-LO pathway by oxLDL to the prooxidant mechanism of the lipoprotein complex. It may initially stimulate the fibroblast reaction against the oxidation challenge as well as metabolic repair, such as during lung inflammation and pulmonary fibrosis.     

Biofilm formation of Candida albicans on the surface of a soft denture‐lining material

Background: Soft denture lining‐materials are more susceptible to microbial adhesion than hard denture base acrylic resin. Poor oral hygiene and Candida albicans infection are common among elderly denture wearers as these patients usually have difficulty in keeping them clean. Purpose: To evaluate the influence of the oral hygiene methods on the formation of a biofilm over a soft denture‐lining material. Material and methods: Twenty volunteers were randomly separated into two groups: G1 and G2. Ten volunteers performed daily hygiene of the prostheses with a soft toothbrush and toothpaste. The G2 performed a treatment identical to G1 but also immersed the prostheses in sodium hypochlorite 0.5% for 20 min, once a week. Quantification of the mean score values of biofilm formation at different times were statistically analysed using analysis of variance and Tukey’s test (α = 0.05). Results: G1 (0.65 ± 0.52) showed the lowest mean score values of biofilm formation. There was statistical difference between G1 and G2. The highest mean score values were found at 6 weeks (1.3 ± 1.08) and were statistically different from other times. Conclusion: The oral hygiene methods had a significant effect in the formation of the biofilm over a soft denture‐lining material.