Cytoplasmic domain of NCAM140 interacts with ubiquitin-fold modifier-conjugating enzyme-1 (Ufc1)

The neural cell adhesion molecule NCAM is implicated in different neurodevelopmental processes and in synaptic plasticity in adult brain. The cytoplasmic domain of NCAM interacts with several cytoskeletal proteins and signaling molecules. To identify novel interaction partners of the cytosolic domain of NCAM a protein macroarray has been performed. We identified the ubiquitin-fold modifier-conjugating enzyme-1 (Ufc1) as an interaction partner of NCAM140. Ufc1 is one of the enzymes involved in modification of proteins with the ubiquitin-like molecule ubiquitin-fold modifier-1 (Ufm1). We also observed a partial co-localization of NCAM140 with Ufc1 and Ufm1 and increased endocytosis of NCAM140 in the presence of Ufm1 suggesting a possible ufmylation of NCAM140 and a potential novel function of Ufm1 for cell surface proteins.     

Doxorubicin inhibits oxidation of 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonate) (ABTS) by a lactoperoxidase/H(2)O(2) system by reacting with ABTS-derived radical

The effect of doxorubicin on oxidation of 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonate) (ABTS) by lactoperoxidase and hydrogen peroxide has been investigated. It was found that: (1) oxidation of ABTS to its radical cation (ABTS*(+)) is inhibited by doxorubicin as evidenced by its induction of a lag period, duration of which depends on doxorubicin concentration; (2) the inhibition is due to doxorubicin hydroquinone reducing the ABTS*(+) radical (stoichiometry 1: 1.8); (3) concomitant with the ABTS*(+) reduction is oxidation of doxorubicin; only when the doxorubicin concentration decreases to a near zero level, net oxidation of ABTS could be detected; (4) oxidation of doxorubicin leads to its degradation to 3-methoxysalicylic acid and 3-methoxyphthalic acid; (5) the efficacy of doxorubicin to quench ABTS*(+) is similar to the efficacy of p-hydroquinone, glutathione and Trolox C. These observations support the assertion that under certain conditions doxorubicin can function as an antioxidant. They also suggest that interaction of doxorubicin with oxidants may lead to its oxidative degradation.     

Recent developments and applications of immobilized laccase

Laccase is a promising biocatalyst with many possible applications, including bioremediation, chemical synthesis, biobleaching of paper pulp, biosensing, textile finishing and wine stabilization. The immobilization of enzymes offers several improvements for enzyme applications because the storage and operational stabilities are frequently enhanced. Moreover, the reusability of immobilized enzymes represents a great advantage compared with free enzymes. In this work, we discuss the different methodologies of enzyme immobilization that have been reported for laccases, such as adsorption, entrapment, encapsulation, covalent binding and self-immobilization. The applications of laccase immobilized by the aforementioned methodologies are presented, paying special attention to recent approaches regarding environmental applications and electrobiochemistry.     

A globotriaosylceramide (Gb3Cer) mimic peptide isolated from phage display library expressed strong neutralization to Shiga toxins

A Gb₃-trisaccharide mimic peptide was selected with biopanning from a phage display library against anti-Gb₃ antibody to neutralize Shiga toxins (Stxs). Biopanning was carried out on a microplate immobilized with a Fab fragment of anti-Gb₃ antibody and a subtraction procedure screening was applied to enhance specificity. The selected phage clones showed strong affinity to anti-Gb₃ antibody and to Stxs. Among these clones, a 9-mer sequence WHWTWLSEY was determined as the strongest Gb₃ mimic peptide and chemically synthesized. The peptide bound strongly to Stx-1 and Stx-2, though the binding was inhibited with Gb₃Cer. Surface plasmon resonance (SPR) and fluorescent spectroscopy determined that the affinity of the peptide to both Stxs was strong. Neutralization activity was confirmed by in vitro assay with HeLa cells. The Gb₃ mimic peptide potentially has great promise for use against Stxs.     

Antioxidative effect of melatonin on DNA and erythrocytes against free-radical-induced oxidation

The aim of this work is to investigate the antioxidative effect of melatonin (N-acetyl-5-methoxytryptamine) on the oxidation of DNA and human erythrocytes induced by 2,2'-azobis(2-amidinopropane hydrochloride) (AAPH). First, the 50% inhibition concentration (IC50) of melatonin is measured by reacting with two radical species, i.e., 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonate) radical cation (ABTS*+) and 2,2'-diphenyl-1-picrylhydrazyl (DPPH). The IC50 of melatonin are 75microM and 300microM when melatonin reacts with ABTS*+ and DPPH, respectively. Especially, the reactions of melatonin with ABTS*+ and DPPH are the direct evidence for melatonin to trap radicals. Then, melatonin is applied to protect DNA and human erythrocytes against oxidative damage and hemolysis induced by 2,2'-azobis(2-amidinopropane hydrochloride) (AAPH). The presence of melatonin prolongs the occurrence of the oxidative damage of DNA and hemolysis of erythrocytes, generating an inhibition period (t(inh)). The proportional relationship between t(inh) and the concentration of melatonin ([MLT]) is treated by the chemical kinetic equation, t(inh)=(n/R(i))[MLT], in which n means the number of peroxyl radical trapped by an antioxidant, and R(i) stands for the initiation rate of the radical reaction. It is found that every molecule of melatonin can trap almost two radicals in protecting DNA and erythrocytes. Furthermore, quantum calculation proves that the indole-type radical derived from melatonin is much stable than amide-type radical. Finally, melatonin is able to accelerate hemolysis of erythrocytes induced by hemin, indicating that melatonin leads to the collapse of the erythrocyte membrane in the presence of hemin. This may provide detailed information for the usage of melatonin and helpful reference for the design of indole-related drugs.     

Cytoprotective and antioxidant properties of organic selenides for the myelin-forming cells,oligodendrocytes

Here a new series of twenty-one organoselenides, of potential protective activity, were synthesized and tested for their intrinsic cytotoxicity, anti-apoptotic and antioxidant capacities in oligodendrocytes. Most of the organoselenides were able to decrease the ROS levels, revealing antioxidant properties. Compounds 5b and 7b showed a high glutathione peroxidase (GPx)-like activities, which were 1.5 folds more active than ebselen. Remarkably, compound 5a diminished the formation of the oligodendrocytes SubG1 peak in a concentration-dependent manner, indicating its anti-apoptotic properties. Furthermore, based on the SwissADME web interface, we performed an in-silico structure-activity relationship to explore the drug-likeness of these organoselenides, predicting the pharmacokinetic parameters for compounds of interest that could cross the blood-brain barrier. Collectively, we present new organoselenide compounds with cytoprotective and antioxidant properties that can be considered as promising drug candidates for myelin diseases.     

Protective effect of Opuntia ficus-indica L. cladodes against UVA-induced oxidative stress in normal human keratinocytes

Opuntia ficus-indica L. is known for its beneficial effects on human health, but still little is known on cladodes as a potent source of antioxidants. Here, a direct, economic and safe method was set up to obtain water extracts from Opuntia ficus-indica cladodes rich in antioxidant compounds. When human keratinocytes were pre-treated with the extract before being exposed to UVA radiations, a clear protective effect against UVA-induced stress was evidenced, as indicated by the inhibition of stress-induced processes, such as free radicals production, lipid peroxidation and GSH depletion. Moreover, a clear protective effect against apoptosis in pre-treated irradiated cells was evidenced. We found that eucomic and piscidic acids were responsible for the anti-oxidative stress action of cladode extract. In conclusion, a bioactive, safe, low-cost and high value-added extract from Opuntia cladodes was obtained to be used for skin health/protection.     

Beneficial effects of exogenous iodine in lettuce plants subjected to salinity stress

Salinity inhibits plant growth due to ionic and osmotic effects on metabolic processes and nutritional balance, leading to impaired physiological functions. Selenium (Se) and silicon (Si) can be partially alleviated by the effects wrought by NaCl on the plant metabolism. Iodine (I), applied as iodate (IO₃⁻) in biofortification programmes, has been confirmed to improve the antioxidant response in lettuce plants. Thus, the aim of this study was to determine whether the application of IO₃⁻ can improve the response to severe salinity stress in lettuce (Lactuca sativa cv. Philipus). In this work, the application of IO₃⁻ (20-80 μM) in lettuce plants under salinity stress (100 mM of NaCl) exerted a significantly positive effect on biomass and raised the levels of soluble sugars while lowering the Na⁺ and Cl⁻ concentrations as well as boosting the activity of antioxidant enzymes such as SOD, APX, DHAR and GR. Therefore, IO₃⁻ could be considered a possibly beneficial element to counteract the harmful effects of salinity stress.     

A simple method for monitoring chromatography column eluates for laccase activity during enzyme purification

A simple and economical method is described that allows rapid detection of laccase activity in chromatography column fractions during enzyme purification. Aliquots of column eluants are applied to filter paper coated with 2,2-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) containing a numbered grid, and incubated at ambient temperature for 20 min. Indications of enzyme activity are simply observed by a colour change. This method avoids having to manually assay each fraction of a chromatographic run for enzyme activity.     

Radical scavenging and anti-inflammatory activities of (hetero)arylethenesulfonyl fluorides: Synthesis and structure-activity relationship (SAR) and QSAR studies

A series of (hetero)arylethenesulfonyl fluorides (1–58) were synthesized and screened for their in vitro antioxidant (DPPH, ABTS and DMPD methods) and anti-inflammatory activities. The results revealed that compounds 4, 15, 16, 24, 25, 26, 38, 39, 40, and 54 exhibited excellent antioxidant activity using all the three performed antioxidant methods, which were superior to the standard antioxidants ascorbic acid and gallic acid. Compounds 6–9, 11, 18, 19, 21, 22, 30, 39, 40, 44, 45, 48–50, 54, 55 and 57 displayed promising anti-inflammatory activity, which were better than the reference drug indomethacin. Preliminary structure–activity relationship (SAR) revealed that compounds containing electron donating (OH and OCH₃) groups on the phenyl ring possessed excellent antioxidant properties while compounds containing electron-withdrawing (Cl, NO₂, F and Br) groups on the phenyl ring were found to be most potent anti-inflammatory agents. The presence of SO₂F group played a crucial role in increases both antioxidant and anti-inflammatory activities.