Purification and characterization of the α-glucosidase produced by thermophilic fungus <Emphasis Type="Italic">Thermoascus aurantiacus</Emphasis> CBMAI 756

An α-glucosidase enzyme produced by the fungus Thermoascus aurantiacus CBMAI 756 was purified by ultra filtration, ammonium sulphate precipitation, and chromatography using Q Sepharose, Sephacryl S-200, and Superose 12 columns. The apparent molecular mass of the enzyme was 83 kDa as determined in gel electrophoresis. Maximum activity was observed at pH 4.5 at 70°C. Enzyme showed stability stable in the pH range of 3.0–9.0 and lost 40% of its initial activity at the temperatures of 40, 50, and 60°C. In the presence of ions Na⁺, Ba²⁺, Co²⁺, Ni²⁺, Mg²⁺, Mn²⁺, Al³⁺, Zn²⁺, Ca²⁺ this enzyme maintained 90–105% of its maximum activity and was inhibited by Cr³⁺, Ag⁺, and Hg²⁺. The enzyme showed a transglycosylation property, by the release of oligosaccharides after 3 h of incubation with maltose, and specificity for short maltooligosaccharides and α-PNPG. The K_m measured for the α-glucosidase was 0.07 μM, with a V_max of 318.0 μmol/min/mg.     

On the bioreactivity of triorganotin aminobenzoates. Investigation of trialkyl and triarylyltin(IV) esters of 3-amino and 4-aminobenzoic acids

The synthesis and study of trimethyl-, tributyl- and triphenyltin esters of the 3- and 4-aminobenzoic acids are reported. The triorganotin derivatives are characterized by elemental analyses, FT-IR and solution ¹H and ¹³C NMR spectra. The structure of the trimethyltin 4-aminobenzoate is solved by X-ray diffraction and proves to be polymeric in nature with bridging carboxylates and trigonal bipyramidal tin(IV) environment. However, all the compounds become monomeric in solution with a tetrahedral tin coordination environment in chloroform and trigonal bipyramidal in DMSO due to coordination of the solvent as the NMR spectra have revealed. The compounds exhibit variable cytotoxic activity when tested against Κ562 myelogenous leukaemia, HeLa cervical cancer and HepG2 hepatocellular carcinoma cell lines, with the butyl derivatives being the more effective and the methyl ones the less. Interestingly, their antibacterial action was significantly lower when tested against Escherichia coli, while not appreciable direct interaction with DNA has been observed. The above observations account for a mode of action that may be related to their potential interaction with cell membranes and the subsequent inhibition of various signaling processes.     

Metal complexes with the quinolone antibacterial agent N-propyl-norfloxacin: synthesis, structure and bioactivity

Nine new metal complexes of the quinolone antibacterial agent N-propyl-norfloxacin, pr-norfloxacin, with VO(2+), Mn(2+), Fe(3+), Co(2+), Ni(2+), Zn(2+), MoO(2)(2+), Cd(2+) and UO(2)(2+) have been prepared and characterized with physicochemical and spectroscopic techniques while molecular mechanics calculations for Fe(3+), VO(2+) and MoO(2)(2+) complexes have been performed. In all complexes, pr-norfloxacin acts as a bidentate deprotonated ligand bound to the metal through the pyridone and one carboxylate oxygen atoms. All complexes are six-coordinate with slightly distorted octahedral geometry. For the complex VO(N-propyl-norfloxacinato)(2)(H(2)O) the axial position, trans to the vanadyl oxygen, is occupied by one pyridone oxygen atom. The investigation of the interaction of the complexes with calf-thymus DNA has been performed with diverse spectroscopic techniques and has shown that the complexes can be bound to calf-thymus DNA resulting to a B-->A DNA transition. The antimicrobial activity of the complexes has been tested on three different microorganisms. The complexes show equal or decreased biological activity in comparison to the free pr-norfloxacin except UO(2)(pr-norf)(2) which shows better inhibition against S. aureus.     

Mononuclear copper(II) complexes with quinolones and nitrogen-donor heterocyclic ligands: Synthesis, characterization, biological activity and interaction with DNA

The neutral mononuclear copper(II) complexes with the quinolone antibacterial drugs, pipemidic acid and N-propyl-norfloxacin, in the presence or absence of nitrogen-donor heterocyclic ligands, 2,2′-bipyridine, 1,10-phenanthroline or 2,2′-dipyridylamine, have been prepared and characterized spectroscopically. The interaction of copper(II) with the deprotonated quinolone ligand leads to the formation of the neutral mononuclear complexes of the type [Cu(quinolone)₂(H₂O)] (1)–(2) while the presence of the N-donor ligand leads to the formation of the neutral mononuclear complexes of the type [Cu(quinolone)(N-donor)Cl] (3)–(8). In all the complexes, copper(II) is pentacoordinate having a distorted square pyramidal geometry. The electron paramagnetic resonance spectra of 1 and 2 are typical of mononuclear Cu(II) complexes, while for the mixed-ligands complexes 3–8 a mixture of dimeric and monomeric species is indicated. The interaction of the complexes with calf-thymus DNA has been investigated with diverse spectroscopic techniques and has shown that the complexes can be bound to calf-thymus DNA by the intercalative mode. The antimicrobial activity of the complexes has been tested on three different microorganisms. All the complexes show an increased biological activity in comparison to the corresponding free quinolone ligand.     

Synthesis and anti-inflammatory/antioxidant activities of some new ring substituted 3-phenyl-1-(1,4-di-N-oxide quinoxalin-2-yl)-2-propen-1-one derivatives and of their 4,5-dihydro-(1H)-pyrazole analogues

We report the synthesis, anti-inflammatory and antioxidant activities of novel ring substituted 3-phenyl-1-(1,4-di-N-oxide quinoxalin-2-yl)-2-propen-1-one derivatives and of their 4,5-dihydro-(1H)-pyrazole analogues. The tested compounds inhibit the carrageenin-induced rat paw edema (4.5-56.1%) and present important scavenging activities. Compound 2a is the most potent (56.1%) in the in vivo experiment and exhibits promising in vitro inhibition of soybean lipoxygenase (IC(50)<1microM).     

The effect of interval training in children with exercise-induced asthma competing in soccer

A lot of emphasis has been placed in screening individuals with exercise-induced bronchospasm in order to avoid persistence bronchial hyperactivity and consequent chronic silent inflammation of the respiratory tract. The purpose of this study was to evaluate the effect of interval training on the respiratory function and endurance in children with exercise-induced asthma (EIA) participating in the sport of soccer. Twenty-nine boys ages 10-14, who developed EIA after a 6-minute free running test (decline in forced expiratory volume in 1 second: FEV(1)10%), participated in the study. They were divided into 2 groups (experimental: n = 18, and control: n = 11), fulfilling the same criteria (i.e., age, body height and weight, and severity of asthma). The experimental group exercised with the interval training method for a period of 8 weeks, (3 sessions per week), whereas the control group exercised with the usual football program. Measurements were made for FEV(1) and endurance in both groups, before and after the application of training (8 weeks). Following the implementation of the training program, a significant improvement in FEV(1) and endurance was documented in the experimental group, as well as significant differences between the 2 groups. In conclusion, duration and aerobic training via the interval method seems to be beneficial to soccer players with EIA.     

Anti-inflammatory and antioxidant activity of coumarins designed as potential fluorescent zinc sensors

A series of coumarin analogs, designed and synthesised as potential fluorescent zinc probes were evaluated for their biological activity as anti-inflammatory and antioxidant agents. The effect of the synthesised compounds on inflammation, using the carrageenin-induced rat paw oedema model, was studied. In general, the compounds were found to be potent anti-inflammatory agents (26.5-64%). Compound 5 was found to interact significantly with 1,1-diphenyl-2-picryl-hydrazyl stable free radical (DPPH) whereas the remainder were inactive in this assay. The compounds inhibit in general the soybean lipoxygenase and scavenge superoxide anion radicals. The anti-inflammatory activity seems to be connected with their reducing activity. Their RM values were determined as an expression of their lipophilicity. Theoretical calculations of their lipophilicity as clog P were performed indicating that only a poor relationship exists between their lipophilicity and anti-inflammatory activity.     

Electrical Stimulation Improves Microbial Salinity Resistance and Organofluorine Removal in Bioelectrochemical Systems

Fed batch bioelectrochemical systems (BESs) based on electrical stimulation were used to treat p-fluoronitrobenzene (p-FNB) wastewater at high salinities. At a NaCl concentration of 40 g/liter, p-FNB was removed 100% in 96 h in the BES, whereas in the biotic control (BC) (absence of current), p-FNB removal was only 10%. By increasing NaCl concentrations from 0 g/liter to 40 g/liter, defluorination efficiency decreased around 40% in the BES, and in the BC it was completely ceased. p-FNB was mineralized by 30% in the BES and hardly in the BC. Microorganisms were able to store 3.8 and 0.7 times more K⁺ and Na⁺ intracellularly in the BES than in the BC. Following the same trend, the ratio of protein to soluble polysaccharide increased from 3.1 to 7.8 as the NaCl increased from 0 to 40 g/liter. Both trends raise speculation that an electrical stimulation drives microbial preference toward K⁺ and protein accumulation to tolerate salinity. These findings are in accordance with an enrichment of halophilic organisms in the BES. Halobacterium dominated in the BES by 56.8% at a NaCl concentration of 40 g/liter, while its abundance was found as low as 17.5% in the BC. These findings propose a new method of electrical stimulation to improve microbial salinity resistance.     

Isolation and characterization of latent and active polyphenoloxidase in BRS Clara (CNPUV 154-147 × Centennial seedless) and BRS Morena (Marroo seedless × Centennial seedless) seedless table grapes

The seedless grapes BRS Clara and BRS Morena, developed in Brazil, are currently growing in popularity due to their premium texture and taste. However, there are no reports on the polyphenoloxidase (PPO) from these cultivars. In this paper, active and latent PPO from BRS Clara and BRS Morena seedless grapes were extracted using the non-ionic detergents Triton-X-100 (active) and Triton-X-114 (latent), and their catecholase activities were characterized. The PPO extracted using Triton-X-110 exhibited maximum activities at pH 6.0 and at 25 °C. Above 30 °C, a gradual decline in activities was noted, with complete inactivation at 60 °C. The PPO from grapes extracted with Triton-X-114 was activated with 0.2% of the ionic detergent sodium dodecyl sulfate (SDS), and exhibited maximum activities at pH 5.5 and at 30 °C. It was stable until the temperature reached 60 °C.