A dual responsive colorimetric sensor based on polyazomethine and ascorbic acid for the detection of Al (III) and Fe (II) ions.

In the present paper, a novel double cation target colorimetric sensor was developed for the detection of Al (III), and Fe (II) ions. It was composed of ascorbic acid in a polyazomethine matrix, and polyazomethine was used to form a homogenous matrix for mixing ascorbic acid. The photophysical properties of the colorimetric sensor were clarified by using UV-Vis and fluorescence spectrophotometers. It was found that the developed sensor was exhibited good naked eye selectivity, and sensitivity toward Al (III), and Fe (II) ions with excellent photostability. Furthermore, the detection limit of the sensor was calculated as 0.398 µM (0.096 ppm) and 0.185 µM (0.051 ppm) for Al (III), and Fe (II), respectively. The applicability of the colorimetric sensor in environmental (tap and sea waters) and biological (Bovine serum albumin) solutions was also studied, and the results exhibited that the developed sensor could be successfully applied to monitoring environmental and biological samples.

Phytosynthesis of CuONPs via Laurus nobilis: Determination of antioxidant content, antibacterial activity, and dye decolorization potential.

Copper oxide nanoparticles (CuONPs) were phytosynthesized by Laurus nobilis leaf extract, which was used as a reducing and capping agent. UV-vis spectroscopy was applied, and the spectrum of CuONPs gave a peak around 300 and 325 nm. An intense Fourier transform infrared spectroscopy between 4000 and 500 cm-1 wavelengths exhibited exterior functional groups of CuONPs. The results of scanning electron microscopy and transmission electron microscopy revealed that the green synthesized CuONPs were spherical in shape with sizes between 90 and 250 nm. Antibacterial activity of CuONPs was evaluated against both Gram-positive and Gram-negative bacteria. Brilliant Blue R-250 was employed in the dye decolorization studies, and CuONPs achieved 69% decolorization in 60 Min. The antioxidant activity of CuONPs was calculated by analyzing total phenolic compounds and flavonoid content. Furthermore, the reducing power of extract and nanoparticles was determined. Total phenolic compounds of CuONPs were determined as 6.7 µg of pyrocatechol equivalent/mg, while total flavonoids were measured as 236.62 µg catechin/mg sample. Results indicated that the method of CuONP formation is simple and low cost and the phytosynthesized CuONPs had antibacterial, antioxidant, and dye decolorization activity.

Fabrication of PVA-chitosan-based nanofibers for phytase immobilization to enhance enzymatic activity.

In the present paper, polyvinyl alcohol (PVA)-chitosan (CS) nanofibers were fabricated by using the electrospinning method under a constant voltage (23 kV) and the distance (12 cm). Phytase was purified from cowpea seeds and it was immobilized into the PVA-CS nanofibers. The effects of the electrospinning parameters such as enzyme concentration and flow rate on the catalytic activity of the free and immobilized phytase were also studied. The fabricated nanofibers were characterized via FT-IR, SEM, and XRD techniques. PVA-CS nanofiber and phytase containing nanofiber (phytase-PVA-CS) were exhibited a homogenous morphology with an average diameter of about 43.6 ± 13.7 and 65.3 ± 26.0 nm and fiber diameter of nanofiber containing phytase was increased after enzyme immobilization into PVA-CS nanofiber. The optimum pH and temperature of the free and immobilized phytase were also investigated. The obtained results showed that the optimum pH and temperature values of the immobilized enzyme were shifted to higher pH and temperature values after the immobilization of phytase into PVA-CS nanofiber. According to these results of the immobilized phytase, it could be used in some industrial applications such as animal feed, agriculture, pharmaceutical area, and food industry.

Poly(azomethine-urethane) and zeolite-based composite: Fluorescent biosensor for DNA detection.

In the present paper, a highly selective and sensitive fluorescent biosensor based on poly(azomethine-urethane) and zeolite for the determination of DNA molecules was developed. Zeolite was chosen to enhance with anionic or cationic functional groups in polymer matrix and interaction between polymer and DNA. Several parameters such as polymer concentration, pH and incubation time effect on the sensitivity of the fluorescent biosensor were optimized. Linear range was determined between 2.50 and 25.00 nmol/L DNA concentration and limit of detection (LOD) of the biosensor was calculated as 0.095 nmol/L under the optimal conditions. Interference study was also performed in the presence of different amino acids, cations and organic compounds. The results clearly indicated that the tested cations and compounds were not induced a significant fluorescence change and the proposed zeolite-based biosensor was shown a good selectivity for DNA.

Thermally Stable Schiff Base and its Metal Complexes: Molecular Docking and Protein Binding Studies.

In this paper, interaction of Schiff base and its metal complexes carrying naphthalene ring in the structure with bovine serum albumin (BSA) were investigated using UV-vis absorption, fluorescence spectroscopies and molecular docking methods. The effect on the binding mechanism and properties of these compounds containing metal-free, iron and copper ions were also investigated. The fluorescence spectroscopy results showed that fluorescence intensity of BSA in the presence of different concentration of ligands was decreased through a static quenching mechanism. Binding constants (KSV, Kbin and Ka) and thermodynamic parameters (ΔG, ΔH and ΔS) for the ligand-protein interactions were also determined. ΔG values of ligand-protein interaction were calculated in the range - 6.3 to -5.5 kcal/mol. These negative values showed that binding process is spontaneous and, hydrogen bonding and van der Waals force were main interaction of the protein and ligands. ΔH and ΔS value were also calculated in the range of 1.10 to 1.26 kJ/mol and 0.133 to 0.135 kJ/mol. K, respectively. These positive values indicated that the binding process between ligands and BSA are endothermic and electrostatic interaction, respectively.

A novel pullulanase from a fungus Hypocrea jecorina QM9414: production and biochemical characterization.

Pullulanase production from a fungus Hypocrea jecorina QM9414 that produces native extracellular hydrolases having industrial applications was carried out in a shaking flask culture containing 0.5% amylopectin at a pH of 6.50 at 300C. The enzyme was purified 11-fold by ammonium sulfate fractionation, anion-exchange and gel-filtration chromatographies with a yield of 10.12% and a specific activity of 1.36 +/- 0.14 U/mg protein. The molecular mass of pullulanase was estimated to be 130.56 kDa by PAGE and SDS-PAGE, indicating that the native enzyme was a monomer. The optimum pH and temperature for purified enzyme was 6.5 and between 35 degrees-65 degreesC, respectively. The Km values for amylopectin, starch and pullulan as substrates were 10.7, 15.5 and 38.4 mg/mL, respectively. The Vmax values were found to be 3.32, 3.32 and 3.82 deltaA/min for amylopectin, starch and pullulan, respectively. The enzyme was stable at 40-70 degreesC for 30 min, but lost about 33% of its activity at 80 degreesC and about 43% of activity at 90 degreesC and 100 degreesC for the same incubation period. Pullulanase activity was stimulated by CoC1(2), NiC1(2), KI, NaC1, MgC1(2), and LiSO4. The enzyme was slightly inhibited by urea, CaC1(2) and beta3-mercaptoethanol. The enyzmatic characteristics, substrate specificity and the products of hydrolysis indicated that the enzyme was similar to those of type II pullulanases.

New p-Substituted Salicylaldehyde Phenylhydrazone Derivatives: Synthesis, Characterization, and Antioxidant Activities.

A series of new p-nitrophenylhydrazone derivatives 3a-f were synthesized, characterized, and investigated for their antioxidant activities. These compounds have been synthesized by refluxing (p-nitrophenyl)hydrazine with 4-sub-stituted salicylaldehydes. The structures of the compounds were established by IR, (1)H- and (13)C-NMR, and MS data. The antioxidant activities (free radical-scavenging activity, reducing power, metal chelating activity, and total anti-oxidant activity) of the hydrazone compounds were evaluated. All of the compounds exhibited significant activities, while compound 3a, with the shortest chain, showed the highest antioxidant activity in all of the tests.

The effect of combined treatment with niacin and chromium (III) chloride on the different tissues of hyperlipemic rats.

We investigated the effects of a combined treatment with chromium (Cr) and niacin on the spleen, tongue, and lens tissues in terms of lipid peroxidation (LPO), glutathione (GSH), serum catalase (CAT), lactate dehydrogenase (LDH), serum cholesterol, and total lipid levels in normal and hyperlipemic rats. In this study, female 1-year-old Swiss albino rats were used. The rats were randomly divided into four groups. Group I rats (control) were fed with standard pellet chow. Group II rats were fed a lipogenic diet in which 2% cholesterol, 0.5% cholic acid, and 20% sunflower oil were added and were given 3% alcoholic water for 60 days. Group III rats were fed with the same lipogenic diet and were treated with a dose of 250 microg/kg body weight CrCI3 x 6H2O and 100 mg/kg body weight niacin, for 45 days, by gavage. The rats in group IV were fed with pellet chow and treated with 250 microg/kg body weight CrCI3 x 6H2O and 100 mg/kg body weight niacin, by gavage, for 45 days. After 2 weeks, the animals showed symptoms of hyperlipemia. On the 60th day, tissue and blood samples were taken. We have observed decreased CAT activity and GSH levels, increased LDH activity, cholesterol, total lipid, and LPO levels in hyperlipemic rats. Niacin and Cr administration to hyperlipemic rats increased tissue GSH levels and CAT activity and decreased tissue LPO levels and LDH activity, cholesterol, and total lipid levels compared with hyperlipemic rats. We conclude that the administration of a combination of niacin and chromium has a protective effect against oxidative damage to tongue, lens, and spleen tissues as a result of hyperlipemia.

Effects of a combination of niacin and chromium(III)-chloride on the skin and lungs of hyperlipemic rats.

The aim of this study was to investigate the biochemical effects of niacin and chromium(III)-chloride on serum lipid peroxidation, uric and sialic acids, and the extent of lipid peroxidation and glutathione levels in skin and lung tissues of hyperlipidemic rats. In this study, female Swiss albino rats, 12 mo old, were used. They were randomly divided into four groups. Group I animals were fed with a standard pellet diet and water ad libitium. Group II rats were fed with a standard pellet diet and were treated with a dose of 250 microg/kg body weight CrCI(3).6H(2)O and 100 mg/kg body weight niacin, for 45 d, by the gavage technique. Group III rats were fed a lipogenic diet in which 2% cholesterol, 0.5% cholic acid, and 20% sunflower oil were added to the pellet chow. In addition, the animals in this group drank water containing 3% ethanol. This regime was maintained for 60 d. The rats in group IV were maintained in the same food and drink regime as the animals in group III. After 2 wk, the animals showed symptoms of hyperlipemia and they were treated with 250 microg/kg body weight CrCI(3).6H(2)O and 100 mg/kg body weight niacin, by gavage, for 45 d. On d 60, the blood and the skin and lungs samples were taken from animals. In the hyperlipemic groups, a reduction of the lung glutathione level and an increase in serum, lung, and skin lipid peroxidation levels and in serum sialic and uric acid were observed. In rats treated with a combination of niacin and Cr(III), the skin and serum lipid peroxidation and the sialic and uric acid levels decreased while showing an increase of lung glutathione activity. These results suggest that niacin and Cr(III), when administered in combination, have a protective effect against skin and lung tissues damage as a result of hyperlipidemia.