Oxidative Imbalance in HIV-1 Infected Patients Treated with Antiretroviral Therapy

It is generally accepted that oxidative stress is involved in HIV infection. However, the role in oxidative balance of Highly Active Antiretroviral Therapy (HAART) is still debated. In our study we assessed serum oxidant and antioxidant levels in an HIV-1-infected population treated with HAART, and compared them with those of untreated HIV-1 patients and HIV-1-negative subjects. The study included 116 HIV-1-infected patients (86 HAART-treated and 30 untreated), and 46 HIV-negative controls. Serum oxidant levels were significantly higher in the HIV-1 treated group as compared to untreated and control groups. In addition, a decrease of serum total antioxidant status was observed in the HIV-1 treated group. To be noted is that patients who rigorously follow antiretroviral therapy (optimal HAART adherence) have significantly higher oxidative status than those who do not closely follow the therapy (poor HAART adherence). Analysis of variance revealed no significant further increase in oxidative status in HIV-1-infected patients taking antiretroviral and other drugs with the exception of psychiatric drugs (e.g. anxiolytics or antidepressants). Taken together, our results indicate that HAART may affect oxidative stress in HIV-1-infected patients and suggest that antiretroviral therapy plays an important role in the synergy of HIV infection and oxidative stress

Biodegradation of polycyclic aromatic hydrocarbons by pleurotus sajor-caju

Polycyclic aromatic hydrocarbons (PAHs) are considered priority pollutants because they have potentially dangerous effects on the environment and human health. Bioremediation has recently become attractive to restore polluted sites, because it is not expensive and fulfils the most important properties required by the current regulations. In this work the capability of a white-rot fungi, Pleurotus sajor-caju, was assessed for degradation of pyrene and chrysene. The main objective was to investigate the effects of pollutant concentration on the mycelium growth and find the conditions that can enhance the microorganism tolerance when exposed to pyrene and chrysene. The tests carried out in Petri dishes showed that chrysene inhibited mycelium growth, whereas pyrene was well tolerated. Experiments in liquid medium evidenced that the mycelium was able to degrade pyrene with a removal efficienty greater than 90%

Photometric assay for polyphenol oxidase activity in olives, olive pastes, and virgin olive oils

A photometric method is proposed that allows the determination of phenolase activity in olive fruits, olive pastes, and virgin olive oil. The method can also be used to quantify partially purified phenolase from olives, and is based on the coupling between 4-methyl-o-benzoquinone, the reaction product of phenolase toward its substrate 4-methylcatechol, and the aromatic amine 4-amino-N,N-diethylaniline. The deep-blue adduct arising from this reaction has been characterized by means of nuclear magnetic resonance and mass spectrometric techniques and identified as 4-(4'-diethylamino-phenylimino)-2-hydroxy-5-methyl-cyclohexa-2,5-dienone . This compound shows an absorption band, centered (in dichloromethane) at 617 nm, with an c of 11,080 M(-1)cm(-1). The main advantage of the proposed method resides in the high absorption coefficient of the adduct and its ultraviolet/visible absorption pattern, with a gimel(max) in a spectral region void of significant interferences by the pigments that ultimately will probably be present in the extracts to be tested by this proposed method. The method has proven to be sensitive, specific, and reliable

Properties of Thermus aquaticus b-NADH oxidase immobilised on various supports

beta-NADH oxidase purified from Thermus aquaticus was covalently immobilised on various solid supports. The preparations obtained were compared with the soluble enzyme for activity and kinetic properties. Activated glutaryl-PVA was found to be the best support. The immobilised enzyme was less stable at high temperatures than the soluble enzyme. No differences could be detected in the presence of organic solvents.beta-NADH oxidase purified from Thermus aquaticus was covalently immobilised on various solid supports. The preparations obtained were compared with the soluble enzyme for activity and kinetic properties. Activated glutaryl-PVA was found to be the best support. The immobilised enzyme was less stable at high temperatures than the soluble enzyme. No differences could be detected in the presence of organic solvents

3-Hydroxykynurenine as a substrate/activator for mushroom tyrosinase

3-Hydroxykynurenine is a tryptophan metabolite with an o-aminophenol structure. It is both a tyrosinase activator and a substrate, reducing the lag phase, stimulating the monophenolase activity, and being oxidized to xanthommatin. In the early stage of monophenol hydroxylation, catechol accumulation takes place, whereas 3-hydroxykynurenine is substantially unchanged and no significant amounts of the o-quinone are produced. These results suggest an activating action of 3-hydroxykynurenine toward o-hydroxylation of monophenols. 3-Hydroxykynurenine could therefore well act as a physiological device to control phenolics metabolism to catechols and quinonoids. (C) 2003 Elsevier Science (USA). All rights reserved

Improved chromatographic purification of peroxidase and beta–glucosidase from Hordeum vulgare seedlings

Peroxidases (E.C. 1.11.1.7., hydrogen donor oxidoreductase) utilize hydrogen peroxide or substituted peroxides for the oxidation of a large number of substrates. Peroxidases are widely distributed and have been isolated from many higher plants (1). The wide distribution of the enzyme suggests that it could be of great biological importance, but the physiological functions and metabolic control of these enzymes are still poorly understood. The simultaneous presence of amine oxidase and peroxidase in cell walls suggests that the peroxide generated on oxidation of the amines could be utilized by the peroxidase (2,3). Recently we have purified an amine oxidase from Hordeum vulgare (4) and we have attempted to purify the peroxidase in order to study in vitro the reconstituted coupled system. Beta-glucosidase (beta-D-glucoside glucohydrolase E.C. 3.2.1.21.) is capable of transforming glucosides in glucose and the corresponding aglycone or disaccarides as cellobiose, sophorose, gentiobiose. This enzyme is widely distributed in plants, fungi, bacteria, yeasts and animals (5, 6). In the homogenate of Hordeum vulgare seedlings we also found beta-glucosidase activity and also attempted to purify beta-glucosidase. This enzyme copurified whit peroxidase up to the last step. We report here the isolation of peroxidase and Beta-glucosidase from Hordeum vulgare seedlings: some molecular and kinetic properties are given

Diafiltration in the presence of ascorbate in the purification of mushroom tyrosinase

In the present paper a method for the extraction of Agaricus bisporus tyrosinase, based on the use of a diafiltration procedure in the presence of ascorbate, is proposed. During the extraction of tyrosinase the oxidation of mushroom phenolics was avoided, keeping phenolic compounds in their reduced form throughout the extraction step. Their complete removal by means of a diafiltration apparatus was achieved. The method here described represents a useful way to obtain an enzymic solution of tyrosinase, devoid of phenolics and melanic compounds

Modelling and optimization of poly-aromatic-hydrocarbons biodegradation by Bulab 5738

In this work, the bacterial consortium Bulab 5738 was used to simultaneously remove pyrene, phenanthrene and catechol from aqueous solutions. The bacterial population growth was estimated by means of optical density measurements while HPLC was used to quantify the pollutant concentration in the solution. The obtained data were used to model the systems, in term of biomass population and substrate concentration. The effects of pollutant concentration values were analysed using the outputs of a full factorial experimental design

Detection of parameters enhancing the performance of white-rot fungi for degradation of Poly-Aromatic Hydrocarbons through design-of-experiment methodologies

The aim of this work is to evaluate the tolerance and the growth capabilities of a white rot fungus, the Pleurotus-Sajor Caju, when exposed to Poly-Aromatic Hydrocarbons. The research was carried out by using in vitro systems developed on Petri dishes, where microbial strains are exposed to chemical pollutants, in particular pyrene and chrysene along with addition of surfactants, peptone, copper sulphate and lecithin that may promote fungal growth and tolerance. It was found that the fungal population growth is strongly inhibited by chrysene presence. On the other hand the pyrene has a mild negative impact on the micelyal growth, which seems to be positively influenced by the presence of Tween 80 and copper sulphate