Normal human dermal fibroblasts: proteomic analysis of cell layer and culture medium.

Proteins present within the cell layer and those released in the cell medium from in vitro cultured normal human dermal fibroblasts were separated and characterized in terms of their isoelectric point and molecular weight, by two-dimensional (2-D) gel electrophoresis. All spots in the synthetic gel were firstly analyzed by the Melanie 3 software and compared with those of breast cancer cells, colorectal epithelial cells, HL60, lymphoma cells, and platelets, already available on-line. From the identification of 144 spots from both the cell layer and the medium, we were able to recognize 89 different proteins, since a certain number of spots represented different isoforms of the same molecule. Identifications were performed by matching with on-line 2-D databases, and by matrix assisted laser-desorption/ionization-time of flight-mass spectrometry (MALDI-TOF-MS), in order to confirm the identification by matching, or to identify new proteins. The procedure we used allows (i) to design a highly reproducible reference map of the proteome of adult human normal fibroblasts in culture, (ii) to evaluate protein species produced in the cell layer as well as those released in the culture medium, and (iii) to compare data from gel matching with those obtained by MS. This work represents an essential step for a better knowledge of mesenchymal cells, given the widespread use of this cell type in both clinical and experimental investigations.     

Isoelectric focusing identification of four freshwater fish commercially labeled "perch"

Isoelectric focusing (IEF) was used to distinguish 4 freshwater fish species that are sold in the European Union under the generic label of "perch": Perca fluviatilis (European perch), Lates niloticus (Nile perch), Stizostedion lucioperca (European pikeperch), and Morone chrysops x saxatilis (Sunshine bass). These species have different commercial values but are easily interchangeable because they are sold already filleted, in view of the numerous bones of the whole fish. IEF of the water-soluble proteins extracted from fish muscle resulted in species-specific patterns. None of the bands was common to all 4 species. Intraspecies polymorphism was low and did not concern the bands identified as characteristic of the species.     

DSC and Raman study on the effect of lysozyme and bovine serum albumin on phospholipids liposomes

In this paper, the effect of increasing amounts of lysozyme (Lyso) and bovine serum albumin (BSA) on the behaviour of lecithin (DMPC) and cephalin (DMPE) liposomes was investigated by means of Raman and DSC techniques. The results showed that both proteins affected, but in a different way, both lecithin and cephalin liposomes. In the samples with lower Lyso concentrations (up to 2 % w/w), a small decrease on the main transition temperature (T _m) was observed, whereas T _m increased by further addition of Lyso (up to 15.0 % w/w). At the same time, an increase of about 20 % in the ΔH of the transition was observed. Pre-transition was also affected in a greater extent by protein presence. When BSA interacted with liposomes, a smaller increase in the T _m values was observed with a contemporary increase of about 8 % in the associated ΔH. The data suggested that the BSA–liposomes interaction involves only the external surface of the bilayer, excluding thus any penetration into the liposomal hydrophobic core. On the contrary, a partial penetration into the bilayer is suggested when Lyso is added to liposomes. Both considered proteins strengthened the overall bilayer structure of DMPC liposomes, suggesting a decrease in the membrane permeability. Moreover, Lyso secondary structure changed by interaction with liposomes, as demonstrated by the Raman spectra behaviour, in particular in the case of DMPE.     

Force field and multinuclear nmr study of the conformational properties of thiolane-1-oxide and its mono and dimethyl derivatives

Force field calculations and ¹H, ¹³C and ¹⁷O NMR data are reported for thiolane S-oxide and several of its mono and dimethyl derivatives. For comparison carbon-13 and oxygen-17 chemical shifts of the corresponding S-dioxides are also reported. According to force field calculations and NMR data the conformation of S-oxides depends on the number and on the position of ring substituents. Oxygen-17 chemical shifts of thiolane S-oxides are apparently not very sensitive to ring substitution and to the configuration of the sulfinyl group. This is however the result of conformational changes which cannot be easily predicted. For 2-methyl derivatives δ₁₇₀ allows an easy identification of the cis and trans isomers.     

Synthesis and characterization of gold nanoparticles stabilized by palladium(II) phosphine thiol

This work is focused on the synthesis of innovative hybrids made by linking gold nanoparticles to protected organometallic Pd(II) thiolate. The organometallic protected Pd(II) thiolate, i.e. trans-thioacetate-ethynylphenyl-bis(tributylphosphine)palladium(II) has been synthesized, in situ deprotected and linked to Au nanoparticles. In this way new hybrid, with a direct link between Pd(II) and Au nanoparticles through a single S bridge, has been isolated. The combination of the organometallic Pd(II) thiol with gold nanoparticles allows the enhancement and tailoring of electronic and optical properties of the new organic-inorganic nano-compound. Single-crystal gold nanoparticles, uniform in shape and size were obtained by applying a modified two-phase method (improved Brust-Schiffrin reaction). In addition, the chemical environment of the Au nanoparticles was investigated and a covalent bonding between Au nanoparticles and the organometallic thiols was observed.     

13C and 17O chemical shifts and conformational analysis of mono- and di-methyl-substituted thiane 1-oxide and thiane 1,1-dioxide

The ¹³C and ¹⁷O (natural abundance) chemical shifts of several mono- and di-methyl ring-substituted thiane 1-oxides and thiane 1,1-dioxides are reported. The cis and trans isomers of methyl-substituted thiane 1-oxide are readily identified by ¹³C and ¹⁷O NMR. In particular, the ¹⁷O NMR signals of axial SO groups are found several ppm upfield of those of the equatorial counterparts. The proportion of axial and equatorial conformers of thiane 1-oxide in different solvents has been measured by low-temperature ¹³C NMR. In THF the proportion of the axial conformer is higher than in CD₂Cl₂ whereas in CDCl₃ or CHF₂Cl the conformational preference is reversed and the equatorial conformer is slightly favoured.     

High-performance liquid chromatography and capillary electrophoresis: methodological challenges for the determination of biologically relevant low-aliphatic aldehydes in human saliva

Tobacco smoke is involved in the pathogenesis of cardiovascular and respiratory diseases and also has a local toxic effect in the oral cavity. Low-aliphatic aldehydes, such as formaldehyde, acetaldehyde and acrolein, are among the main components of mainstream cigarette smoke and their local noxious and carcinogenic effects in the oral cavity and upper gastrointestinal tract are well-known. Although various studies have been performed so far to determine their content in cigarette smoke, none has included the direct measurement of these compounds in the saliva of smoking and nonsmoking subjects. Thus, in an attempt to verify whether typical chromatographic (high-performance liquid chromatography, HPLC) and/or electrophoretic (capillary electrophoresis, CE) techniques could be reliable methods for determining the levels of these analytes in human saliva, we submitted specimens obtained from a selected population of heavy, moderate, and nonsmoking subjects to HPLC and CE analyses. Both methods showed good reproducibility in terms of migration times and peak height and/or areas and had comparable linearity. Quantitative analyses performed on the specimens investigated evidenced a 3.5-fold increase of low-aliphatic aldehydes in saliva of nonsmoking subjects after they have smoked a single cigarette and a further 2-fold increase of these compounds in saliva of smokers with a daily consumption of 10 or more cigarettes.     

Raman and SERS study on cimetidine–metal complexes with biomedical interest

Cimetidine (cim) is one of the most potent histamine H₂‐receptor antagonists for inhibiting excessive acid secretion caused by histamine; it has been hypothesized that the therapeutic effects can be related to its interactions with metal ions. Raman spectra of the solid cim with Co(II), Cu(II), Ni(II) and Zn(II) metal complexes show that they can adopt two different structures: one is octahedral and the other, with Zn(II), is probably tetrahedral. The octahedral structure appears to be distorted both by the different metal ions as well as by the different anion present. The study was extended to very dilute solutions (ppm range) by using the surface‐enhanced Raman scattering (SERS) technique, mimicking the physiological concentrations of cim and its metal complexes. SERS spectra suggest that, upon the binding of cim to silver colloids, the formation of stable 1:2 cim–metal complexes is excluded, the formation of 1:1 adduct appearing more probable; in this product the metal reaches its total coordination shell by complexion with water molecules. To better explain the binding mechanism of cim to a metal (Ag) surface, we performed theoretical B3LYP calculations on cim alone as well as on cim bonded to an Ag₂ metal cluster in presence of water, observing a sufficiently good agreement between experimental and theoretical wavenumbers. Copyright © 2010 John Wiley & Sons, Ltd.     

Binuclear Pd(II) complexes with alkynyl ligands and functionalised tail-groups: Molecular and electronic structure studied by XPS and EXAFS

The binuclear transition metal dialkynyl bridged Pd(II) complexes trans,trans-[ClPd(PBu₃)₂–CC–C₆H₄–C₆H₄–CC–Pd(PBu₃)₂Cl] and trans,trans-[CH₃OC–S–Pd(PBu₃)₂–CC–C₆H₄–C₆H₄–CC–Pd(PBu₃)₂–S–COCH₃] were synthesized and investigated by X-ray Photoemission (XPS) and X-ray Absorption (XAS) spectroscopies. XPS measurements lead to assess that the thiolate terminal group does not affect dramatically the electronic structure of the transition metal, and as a consequence the two complexes are expected to possess analogous molecular structure. XAS data analysis suggested a square-planar geometry around the palladium center in both binuclear compounds.     

Atrazine toxicity reduction following H2O2/TiO2- photocatalyzed reaction and comparison with H2O2- photolytic reaction

An atrazine photodegradation study carried out by a Q-Panel suntest apparatus is reported in this work. H2O2/TiO2 photocatalyzed reaction yield and parameters (time, irradiance, temperature, H2O2 (40%) volume, TiO2 amount) were exactly determined relating to the used atrazine concentration. An experimental kinetic study was performed to establish the reaction order in fixed conditions. Using a biosensor method, 10(-4) M Atrazine solution toxicity and final photocatalytic reaction solution toxicity were quantitatively determined. A consistent toxicity decrease was observed on passing from the analyte to the products of the photocatalytic reaction. An analogous photolytic reaction carried out in absence of TiO2, but in the same experimental conditions of time, irradiance, temperature and H2O2 volume, brings to a toxicity increase.