Nitrones: not only extraordinary spin traps, but also good nitric oxide sources in vivo.

Free radicals are involved in the development of reperfusion injuries. Using a spin trap, the intensity of such lesions can be reduced. Nitrones (effective in vivo spin traps) were tried in this work as in vivo nitric oxide donors. Nitrite and nitrate concentration values (rabbit blood) were used as biomarkers of nitric oxide production. Most nitrones did not increase plasma concentrations of nitrite and nitrate; on the contrary, reduced plasma concentrations of these indicators were noted. However, glyoxal isopropyldinitrone, in a dose of 50 mg kg-1, was highly effective in increasing nitric oxide production. At the same time, nitrones do not react with hepatic homogenates, proving that the release of nitric oxide takes place in the tissues and is not related to hepatic metabolism. Before using nitrones in vivo, they were tested in vitro for the ability to release nitric oxide following a reaction with the hydroxyl radical.

Cd(II), Zn(II) and Cu(II) Bioadsorption on Chemically Treated Waste Brewery Yeast Biomass: The Role of Functional Groups.

Here we study the role of functional groups from waste brewery yeast Saccharomyces cerevisiae cells in the bioadsorption of Cd(2+), Zn(2+) and Cu(2+) ions. In order to clarify the role of these functional groups, the brewery yeast was pretreated chemically, thereby helping to determine the mechanisms responsible for binding the target metals. SEM studies were performed to examine the surface microstructure of the adsorbent in pure as well as pretreated forms. The biomass was characterized using FTIR analysis, which indicated that hydroxyl, carboxyl and amid groups are present on the biomass surface. When carboxyl groups were modified by various chemical treatments, the adsorption capacity decreased dramatically, showing that carboxyl groups play a fundamental role in the bioadsorption process. The residual metallic ion concentrations were determined using an Atomic Absorption Spectrophotometer (AAS). Pseudo-first and second-order kinetic models were used to describe the bioadsorption process.

Laboratory tests for the phytoextraction of heavy metals from polluted harbor sediments using aquatic plants.

The aim of this study was to investigate the concentrations and pollution levels of heavy metals, organochlorine pesticides, and polycyclic aromatic hydrocarbons in marine sediments from the Leghorn Harbor (Italy) on the Mediterranean Sea. The phytoextraction capacity of three aquatic plants Salvinia natans, Vallisneria spiralis, and Cabomba aquatica was also tested in the removal of lead and copper, present in high concentration in these sediments. The average detectable concentrations of metals accumulated by the plants in the studied area were as follows: >3.328 ± 0.032 mg/kg dry weight (DW) of Pb and 2.641 ± 0.014 mg/kg DW of Cu for S. natans, >3.107 ± 0.034 g/kg DW for V. spiralis, and >2.400 ± 0.029 mg/kg DW for C. aquatica. The occurrence of pesticides was also analyzed in the sediment sample by gas chromatography coupled with mass spectrometry (GC/MS). Due to its metal and organic compound accumulation patterns, S. natans is a potential candidate in phytoextraction strategies.

Phytoremediation capacity of aquatic plants is associated with the degree of phytochelatin polymerization.

Phytochelatins (PCs) play important role in phytoremediation as heavy metal binding peptides. In the present study, the association between heavy metal removal capacity and phytochelatin synthesis was compared through the examination of three aquatic plants: Elodea canadensis, Salvinia natans and Lemna minor. In case of a Cd treatment, or a Cd treatment combined with Cu and Zn, the highest removal capacity was observed in L. minor. At the same time, E. canadensis showed the lowest removal capacity except for Zn. The heavy metal-induced (Cu+Zn+Cd) oxidative stress generated the highest ascorbate level in L. minor. Cd in itself or combined with the other two metals induced a 10-15-fold increase in the amount of ɣ-glutamylcysteine in L. minor while no or smaller changes were observed in the other two species. Correspondingly, the total PC content was 6-8-fold greater in L. minor. In addition, PCs with higher degree of polymerization were only observed in L. minor (PC4, PC6 and PC7) while PC2 and PC3 occurred in E. canadensis and S. natans only. The correlation analysis indicated that the higher phytoremediation capacity of L. minor was associated with the synthesis of PCs and their higher degree of polymerization.

Biological removal of triphenylmethane dyes from aqueous solution by Lemna minor.

The aim of this study is to investigate and develop a phytoremediation method for the removal of two triphenylmethane dyes (crystal violet and malachite green) using an aquatic plant, Lemna minor. The effects of operational parameters such as aquatic plant quantity, initial dye concentration, initial pH of the solutions and temperature of the medium were studied in order to determine the optimum phytoremediation conditions. The plant's photosynthetic pigments were determined quantitatively in order to detect the plant's response to abiotic stress. During the phytoremediation experiments the parallel sub-processes (phytosorption, phytoextraction, phytodegradation) were observed and analysed. The mechanisms of phytoremediation were studied using Fourier transformation infrared spectroscopy, ultraviolet-visible spectroscopy, thin layer chromatography and Energy-dispersive X-ray spectroscopy. Results show that the plant tolerated high concentrations (300 mg/L) of dyes, and was able to remove from the environment and accumulate in its cells the dyes up to a significant percentage (crystal violet was removed by about 80% and malachite green by 90%).

Cadmium (II) ions removal from aqueous solutions Using Romanian untreated fir tree sawdust a green biosorbent.

Biosorption of cadmium ions from synthetic aqueous solution using popular Romanian fir tree sawdust (Abies Alba) as biosorbent, was investigated in this work. Prior to its utilization the considered biomass was washed, dried and sieved without further chemical treatments. The biosorbent was characterized using humidity, density and elemental analysis determinations and FTIR. FTIR analysis indicated that, on the biomass surface hydroxyl and carboxyl groups are presented. The effect of different biosorption parameters was studied. Higher biomass quantity, neutral pH, slightly elevated temperature and high cadmium ions concentration are all favouring the biosorption process. Equilibrium (Langmuir and Freundlich isotherm), kinetics and thermodynamics of the considered biosorption process were discussed in details. Equilibrium was best described by the Langmuir isotherm, while the kinetic of the process was best described by the pseudo-second-order model, suggesting monolayer coverage and a chemisorption process. Thermodynamic parameters showed that cadmium biosorption process on fir tree sawdust is an endothermic process.

Accumulation and distribution of iron, cadmium, lead and nickel in cucumber plants grown in hydroponics containing two different chelated iron supplies.

Cucumber plants grown in hydroponics containing 10 µM Cd(II), Ni(II) and Pb(II), and iron supplied as Fe(III) EDTA or Fe(III) citrate in identical concentrations, were investigated by total-reflection X-ray fluorescence spectrometry with special emphasis on the determination of iron accumulation and distribution within the different plant compartments (root, stem, cotyledon and leaves). The extent of Cd, Ni and Pb accumulation and distribution were also determined. Generally, iron and heavy-metal contaminant accumulation was higher when Fe(III) citrate was used. The accumulation of nickel and lead was higher by about 20% and 100%, respectively, if the iron supply was Fe(III) citrate. The accumulation of Cd was similar. In the case of Fe(III) citrate, the total amounts of Fe taken up were similar in the control and heavy-metal-treated plants (27-31 µmol/plant). Further, the amounts of iron transported from the root towards the shoot of the control, lead- and nickel-contaminated plants were independent of the iron(III) form. Although Fe mobility could be characterized as being low, its distribution within the shoot was not significantly affected by the heavy metals investigated.

Leaching of antimony from polyethylene terephthalate (PET) bottles into mineral water.

The Sb leaching from polyethylene terephthalate (PET) package material into 10 different brands of still (non-carbonated) and sparkling (carbonated) Hungarian mineral water purchased in supermarkets was investigated by inductively coupled plasma sector field mass spectrometry (ICP-SF-MS). The Sb concentration measured in PET package materials varied between 210 and 290 mg/kg. Generally, the Sb concentration of still mineral water was lower than that of sparkling in the case of identical storage time. For modelling improper storage conditions, storage time (10-950 days), temperature (22 degrees C-70 degrees C), illumination (dark vs. 23 W daylight lamp for 116 h) as well as bottle volume (0.5, 1.0 and 1.5 L) were taken into consideration. Under certain extreme light and temperature storage conditions, the Sb concentration of some samples exceeded the concentration value of 2 ng/mL. The extent of Sb leaching from the PET recipients of different brands of mineral water can differ by even one order of magnitude in experiments conducted under the same conditions. Thus, the adequate selection of the polymer used for the production of the PET bottle for the solar water disinfection (SODIS) procedure seems to ensure low Sb levels in the water samples.

Role of chemical structure in molecular recognition by transferrin.

Studies of molecular recognition of chiral compounds by proteins are of importance from many points of view. The biological role of proteins in their interaction with small molecules is of fundamental interest and can be used in many different fields, for instance for in vitro analysis of optically active compounds. Studies in these areas need a detailed study of the interaction sites on the protein surface and the relationship between chemical structure and the complex formation ability of small molecules, such as drugs. The electrophoretic migration of charged compounds through a protein zone may provide information about the surface properties of the macromolecule in the interaction site. The interaction of human serum transferrin with tryptophan-methyl- (TME), ethyl- (TEE) and butyl-esters (TBE) has been investigated by capillary electrophoresis (CE) and model calculations. Differences in the separation of tryptophan derivatives were obtained by varying experimental parameters such as, pH, ionic strength of background electrolyte and the length of transferrin zone. Limited separation of the enantiomer pairs were observed at pH 5 and 7 with a maximum resolution at pH 6. The size of the ligands coupled to the chiral centre has importance in stereoselective recognition; however, a direct comparison of resolution different in same runs may lead to false conclusion if the experimental conditions are not comparable. With a careful evaluation of the data we obtained significant differences between the resolution of the smallest enantiomer pair compared to those of tryptophan derivatives with longer alkyl chains.

Experimental and quantum chemical study on the vibrational spectroscopy of N-methylphenothiazines: part 1.

In this work the authors deal with the vibrational spectroscopy of three derivatives of phenothiazine: the 10-methyl-10H-phenothiazine, the 10 methyl-10H-phenothiazine-3-carbaldehyde and the 10-methyl-10H-phenothiazine-3-yl-methanol. The authors investigated the vibrational spectroscopic behaviour of the phenothiazine skeleton and dealt with the aldehyde and the alcohol substituent effect on the vibrational spectroscopic and structural properties of these skeleton. The infrared and Raman spectra of the compounds have been recorded in condensed state. The Gaussian 98 program package was applied with the ab initio HF method since in this case beside the infrared also the Raman spectoroscopic properties appear in the output file. On the basis of the calculated force constants and geometric parameters, normal coordinate analysis was applied for the interpretation of the experimental vibrational spectra. Problems arose with the choice of the internal coordinates of the molecules. Full interpretations of the vibrational fundamentals of the compounds are presented. The relative mean deviations between the measured and calculated frequencies were below 1%.

Separation of N-alkyl phenothiazine sulfones by HPTLC using an optimum mobile phase.

In high performance thin layer chromatography some form of optimization is necessary if complete separation of all components is required. The selection of mobile phase composition is one of the most important components of an optimization strategies. The aim of this paper is the separation of the N-alkyl phenothiazine sulfones by high performance thin layer chromatography using an optimum mobile phase system. The optimum composition of mobile phase (toluene-ethyl ether-chloroform, 30:50:20, v/v) are given by the maximum of objective function (F(obj)=10.6110).