Transformation of N ′,N ′-dimethyl-N -(hydroxyphenyl)ureas by laccase from the white rot fungus Trametes versicolor

Transformation of N′,N′-dimethyl-N-(hydroxyphenyl)ureas was assayed in the presence of purified laccase produced by the fungus Trametes versicolor. The para- and ortho-hydroxyphenyl derivatives were enzymatically transformed, whereas the meta derivative was not. The performance of laccase-mediated transformation depended on the pH, with an optimum for the para-derivative degradation rate at pH 5. The pH also influenced the nature of the reaction products. The chemical was exclusively oxidised into p-benzoquinone at pH 3 and into mainly N′,N′-dimethyl-N-[(2,5-cyclohexadiene-1-one)-4-ylidene]urea at pH 6. The ortho- derivative was transformed essentially into insoluble purple compounds, probably appearing as polymers resulting from coupling of the parent compound. Received: 14 September 1998 / Received revision: 23 November 1998 / Accepted: 29 November 1998     

Large-scale production of CMP-NeuAc and sialylated oligosaccharides through bacterial coupling

A large-scale production system of cytidine 5′-monophospho-N-acetylneuraminic acid (CMP-NeuAc) and sialyloligosaccharides was established by a whole-cell reaction through the combination of recombinant Escherichia coli strains and Corynebacterium ammoniagenes. For the production of CMP-NeuAc, two recombinant E. coli strains were generated that overexpressed the genes of CMP-NeuAc synthetase and CTP synthetase, respectively. C. ammoniagenes contributed to the formation of UTP from orotic acid. CMP-NeuAc was accumulated at 27 mM (17 g/l) after a 27-h reaction starting with orotic acid and N-acetylneuraminic acid. When E. coli cells that overexpressed the α-(2 → 3)-sialyltransferase gene of Neisseria gonorrhoeae were put into the CMP-NeuAc production system, 3′-sialyllactose was accumulated at 52 mM (33 g/l) after an 11-h reaction starting with orotic acid, N-acetylneuraminic acid, and lactose. Almost no oligosaccharide byproducts other than 3′-sialyllactose were observed after the reaction. The production of 3′-sialyllactose at a 5-l jar fermenter scale was almost the same as that at a beaker scale, which indicated the high potential of the 3′-sialyllactose production on an industrial scale. Received: 9 July 1999 / Received revision: 17 September 1999 / Accepted: 10 October 1999     

Purification, characterization, and primary structure of a chitinase from Pseudomonas sp. YHS-A2

A chitinase gene (chiA) from Pseudomonas sp. YHS-A2 was cloned into Escherichia coli using pUC19. The nucleotide sequence determination revealed a single open reading frame of chiA comprised of 1902 nucleotide base pairs and 633 deduced amino acids with a molecular weight of 67,452 Da. Amino acid sequence alignment showed that ChiA contains two putative chitin-binding domains and a single catalytic domain. Two proline-threonine repeat regions, which are linkers between catalytic and substrate-binding domains in some cellulases and xylanases, were also found. From E. coli, ChiA was purified 12.8-fold relative to the periplasmic fraction. The Michaelis constant and maximum initial velocity for p-nitrophenyl-N,N′-diacetylchitobiose were 1.06 mM and 44.4 μmol/h per mg protein, respectively. The purified ChiA binds not only to colloidal chitin but also to other substrates (avicel, chitosan, and xylan), but the binding affinity of avicel, chitosan, and xylan is around 10 times lower than that of colloidal chitin. The reaction of ChiA with colloidal chitin and chitooligosaccharides (trimer-hexamer) produced an end product of N,N′-diacetylchitobiose, indicating that ChiA is a chitobiosidase. Received: 29 October 1999 / Received revision: 16 March 2000 / Accepted: 24 March 2000     

Effects of shade on physiological changes,oxidative stress,and total antioxidant power in Thai Brahman cattle

The purpose of this study was to assess the effects of artificial shade, tree shade, and no shade on physiological changes, oxidative stress, and total antioxidant power in Thai Brahman cattle. Twenty-one cattle were divided into three groups: cattle maintained under artificial shade, under tree shade, and without shade. On days 1, 7, 14, 21, and 28 of the experimental period, after the cattle were set in individual stalls for 2 h, physiological changes, thiobarbituric acid reactive substances (TBARS), and total antioxidant power were investigated. The results revealed that the respiratory rate, heart rate, sweat rate and the neutrophil/lymphocyte ratio of the no-shade cattle were significantly higher than those of cattle maintained under artificial shade and tree shade (P < 0.05). During the early period of heat exposure, the total antioxidant power of the no-shade cattle was lower than those of cattle maintained under artificial shade and tree shade, but the total antioxidant power of cattle maintained under artificial shade and tree shade were not different (P > 0.05). However, rectal temperature and packed cell volume of the cattle in all groups did not differ (P > 0.05). These results showed that artificial shade and tree shade can protect cattle from sunlight compared to no shade, and that the effectiveness of tree shade for sunlight protection is at an intermediate level.     

Antioxidant effects of different extracts from Melissa officinalis, Matricaria recutita and Cymbopogon citratus

Considering the important role of oxidative stress in the pathogenesis of several neurological diseases, and the growing evidence of the presence of compounds with antioxidant properties in the plant extracts, the aim of the present study was to investigate the antioxidant capacity of three plants used in Brazil to treat neurological disorders: Melissa officinalis, Matricaria recutita and Cymbopogon citratus. The antioxidant effect of phenolic compounds commonly found in plant extracts, namely, quercetin, gallic acid, quercitrin and rutin was also examined for comparative purposes. Cerebral lipid peroxidation (assessed by TBARS) was induced by iron sulfate (10 μM), sodium nitroprusside (5 μM) or 3-nitropropionic acid (2 mM). Free radical scavenger properties and the chemical composition of plant extracts were assessed by 1′-1′ Diphenyl-2′ picrylhydrazyl (DPPH) method and by Thin Layer Chromatography (TLC), respectively. M. officinalis aqueous extract caused the highest decrease in TBARS production induced by all tested pro-oxidants. In the DPPH assay, M. officinalis presented also the best antioxidant effect, but, in this case, the antioxidant potencies were similar for the aqueous, methanolic and ethanolic extracts. Among the purified compounds, quercetin had the highest antioxidant activity followed by gallic acid, quercitrin and rutin. In this work, we have demonstrated that the plant extracts could protect against oxidative damage induced by various pro-oxidant agents that induce lipid peroxidation by different process. Thus, plant extracts could inhibit the generation of early chemical reactive species that subsequently initiate lipid peroxidation or, alternatively, they could block a common final pathway in the process of polyunsaturated fatty acids peroxidation. Our study indicates that M. officinalis could be considered an effective agent in the prevention of various neurological diseases associated with oxidative stress.     

Role of cyclic nucleotides in pigment translocation within the freshwater shrimp, Macrobrachium potiuna, erythrophore

The participation of cyclic nucleotide-dependent intracellular signalling pathways in the pigment translocation induced by pigment-dispersing hormone (α -PDH) or pigment-concentrating hormone (PCH) was investigated in the erythrophores of the freshwater shrimp, Macrobrachium potiuna. Cholera toxin, forskolin and dibutyryl cyclic adenosine 3′5′ monophosphate (dbcAMP) were able to induce pigment dispersion with effective agonist concentrations for half maximal response (EC₅₀s) of 2.8 · 10⁻¹¹ mol · l⁻¹, 7.0 · 10⁻⁷ mol · l⁻¹ and 3.3 · 10⁻⁷ mol · l⁻¹, respectively. KT5720 (10⁻⁷ mol · l⁻¹ and 10⁻⁶ mol · l⁻¹) significantly shifted the dose response curve to α -PDH to the right. Dibutyryl cyclic guanosine 3′5′ monophosphate (dbcGMP) was ineffective in inducing either pigment aggregation or dispersion. 2′5′ dideoxyadenosine (DDA) and SQ22,536 essentially elicit a pigment-aggregating response in a dose-dependent manner. These effects were not due to the activation of purinergic receptors, since concentrations up to 10⁻⁴ mol · l⁻¹ of adenosine and adenosine triphosphate (ATP), and up to 10⁻³ mol · l⁻¹ of uracil triphosphate (UTP) did not elicit pigment aggregation. In order to verify if PCH decreased cyclic adenosine 3′5′ monophosphate (cAMP) levels, cumulative dose-response curves to PCH in the absence and presence of pertussis toxin and 8-MOM-IBMX were determined. However, neither drug significantly affected PCH activity. The levels of cAMP in the integument cells of M. potiuna were significantly increased (P < 0.05) by α -PDH (10⁻⁷ mol · l⁻¹) and forskolin (10⁻⁶ mol · l⁻¹), but were not affected by PCH (10⁻⁷ or 10⁻¹⁰ mol · l⁻¹). In conclusion, α -PDH seems to elicit pigment dispersion through the activation of a Gs-protein coupled receptor resulting in cAMP increase and cAMP-dependent protein kinase (PKA) activation. Furthermore, although a decrease in cAMP was assumed to be responsible in turn for the action of PCH, such a decrease could not be directly demonstrated. Accepted: 11 August 1998     

Synthesis of <Emphasis Type="Italic">N</Emphasis>-<Emphasis Type="Italic">Z</Emphasis>, <Emphasis Type="Italic">N</Emphasis>′-Formyl α-Amino Acid Derived Gem-Diamines

A variety of N-carbobenzoxy, N′-formyl gem-diaminoalkyl derivatives have been obtained through Goldsmith-Wick reaction of Z-α-amino acid/peptide acid derived isocyanates with 96% HCOOH in presence of 4-dimethylaminopyridine (DMAP) as catalyst. The reaction proceeds to completion within 2–4 h and results in good yields of the products isolated as stable solids.     

Trace Minerals Status and Antioxidant Enzymes Activities in Calves with Dermatophytosis

The aim of this study was to determine the levels of trace minerals Zn, Cu, and Se, the effect of dermatophytosis on the level of thiobarbituric acid reactive substances (TBARS) as an indicator of lipid peroxidation, the status of enzymatic and nonenzymatic antioxidants, and the relationship between the mentioned trace minerals and antioxidant defense system in calves with dermatophytosis. A total of 21 Holstein calves with clinically established diagnosis of dermatophytosis and an equal number of healthy ones were included in this study. Results showed that 81% of mycotic isolates were Trichophyton verrucosum, while 19% were Trichophyton mentagrophytes. The level of Zn, Cu, Se, and glutathione (GSH) and the activity of the antioxidant enzymes, glutathione peroxidase (GSH-Px), and superoxide dismutase (SOD) were significantly (P ≤ 0.05) lower. The plasma level of TBARS was significantly (P ≤ 0.05) higher in dermatophytic calves compared to healthy controls. SOD activity was fairly correlated with serum Cu and positively correlated with serum Zn in healthy control (r = 0.68, P ≤ 0.05; r = 0.58, P ≤ 0.05) and in calves affected with dermatophytosis (r = 0.73, P ≤ 0.05; r = 0.55, P ≤ 0.05), respectively. GSH-Px activity was highly correlated with whole blood selenium (r = 0.78, P ≤ 0.05) in healthy control and dermatophytic subjects (r = 0.76, P ≤ 0.05). Our results demonstrated that in dermatophytosis, the alteration in the antioxidant enzyme activities might be secondary to changes in their cofactor concentrations.     

Molecular cloning, expression, and purification of pig interleukin-5

 Interleukin-5 (IL-5) is thought to be a key cytokine in allergic inflammation. Pig IL-5 was cloned, sequenced, and expressed to enable us to study of the biological role of IL-5 in pigs used in a model for allergen-induced late-phase reactions. These pigs were sensitized to proteins extracted from Ascaris suum, resulting in hypersensitivity to this antigen in both the skin and airways, and a slight blood eosinophilia. Peripheral blood mononuclear cells from antigen-sensitized pigs were isolated and polyclonally stimulated. Total RNA was extracted and reverse transcribed into cDNA. IL-5 primers based on the cow IL-5 cDNA sequence were used to obtain an initial polymerase chain reaction product. 3′ rapid amplification of cDNA ends (3′RACE) and 5′RACE procedures were applied to identify the 3′ and 5′ ends, respectively. The full-length pig IL-5 cDNA is 405 base pairs long. Mature pig IL-5 was expressed in Escherichia coli with a His-tag for purification. The IL-5 protein is 115 amino acids long, has an estimated molecular weight of 14 000 M _r and forms a biologically active homodimer of 28 000 M _r . Pig IL-5 shows 65% amino acid identity to the human IL-5 sequence and 90, 88, 83, 62, and 61% identity to the cow, sheep, horse, mouse, and rat counterparts. Received: 29 June 1999 / Revised: 22 September 1999     

Quercetin in Lyotropic Liquid Crystalline Formulations: Physical, Chemical and Functional Stability

The purpose of this study was to develop a lyotropic liquid crystalline formulation using the emulsifier vitamin E TPGS and evaluate its behavior after incorporation of a flavonoid, quercetin. The physical (macro and microscopic), chemical (determination of quercetin content by the HPLC method) and functional (determination of quercetin antioxidant activity by DPPH^• assay) stability of the lamellar liquid crystalline formulation containing flavonoid was evaluated when stored at 4 ± 2 °C; 30 ± 2 °C/70 ± 5% RH (relative humidity) and 40 ± 2 °C/70 ± 5% RH during 12 months. The lamellar liquid crystalline structure of the formulation was maintained during the experiment, however chemical and functional stability results showed a great influence of the storage period in all conditions tested. A significant decrease in quercetin content (approximately 40%) was detected during the first month of storage and a similar significant loss in antioxidant activity was detected after 6 months. The remaining flavonoid content was unchanged during the final 6 months of the experimental period. The results suggest possible interactions between quercetin and the liquid crystalline formulation, which could inhibit or reduce the quercetin activity incorporated in the system. In conclusion, the present study demonstrated that incorporation of quercetin (1%) did not affect the liquid crystalline structure composed of vitamin E TPGS/IPM/PG–H₂O (1:1) at 63.75/21.25/15 (w/w/w). Nevertheless, of the total quercetin incorporated in the system only 60% was free to act as an antioxidant.     

Haplotypes of IL12B promoter polymorphisms condition susceptibility to severe malaria and functional changes in cytokine levels in Thai adults

Polymorphic variability in immune response genes, such as IL12B, encoding the IL-12p40 subunit is associated with susceptibility to severe malaria in African populations. Since the role of genetic variation in conditioning severe malaria in Thai adults is largely unexplored, the functional association between IL12B polymorphisms [i.e. IL12Bpro (rs17860508) and IL12B 3′ UTR T/G (rs3212227)], severe malaria and cytokine production was examined in patients with Plasmodium falciparum infections (n = 355) recruited from malaria endemic areas along the Thai–Myanmar border in northwest Thailand. Circulating IL-12p40 (p = 0.049) and IFN-γ (p = 0.051) were elevated in patients with severe malaria, while only IL-12p40 was significantly higher in severe malaria patients with hyperparasitaemia (p = 0.046). Carriage of the IL12Bpro1.1 genotype was associated with enhanced severity of malaria (OR, 2.34; 95% CI, 0.94–5.81; p = 0.066) and hyperparasitaemia (OR, 3.42; 95% CI, 1.17–9.87; p = 0.025) relative to the IL12Bpro2.2 genotype (wild type). Individuals with the IL12Bpro1.1 genotype also had the lowest IL-12p40 (p = 0.002) and the highest IFN-γ (p = 0.004) levels. Construction of haplotypes revealed that carriage of the IL12Bpro-2/3′ UTR-T haplotype was associated with protection against severe malaria (OR, 0.51; 95% CI, 0.29–0.90; p = 0.020) and reduced circulating IFN-γ (p = 0.06). Thus, genotypic and haplotypic variation at IL12Bpro and IL12B 3′ UTR in this population influences susceptibility to severe malaria and functional changes in circulating IL-12p40 and IFN-γ levels. Results presented here suggest that protection against severe malaria in Thai adults is associated with genotypic variants that condition enhanced IL-12p40 and reduced IFN-γ levels.     

IL1RN genetic variations and risk of IPF: a meta-analysis and mRNA expression study

Idiopathic pulmonary fibrosis (IPF) is a rare and devastating lung disease of unknown aetiology. Genetic variations in the IL1RN gene, encoding the interleukin-1 receptor antagonist (IL-1Ra), have been associated with IPF susceptibility. Several studies investigated the variable number tandem repeat (VNTR) or single nucleotide polymorphisms rs408392, rs419598 and rs2637988, with variable results. The aim of this study was to elucidate the influence of polymorphisms in IL1RN on IPF susceptibility and mRNA expression. We performed a meta-analysis of the five case–control studies that investigated an IL1RN polymorphism in IPF in a Caucasian population. In addition, we investigated whether IL1RN mRNA expression was influenced by IL1RN polymorphisms. The VNTR, rs408392 and rs419598 were in tight linkage disequilibrium, with D′ > 0.99. Furthermore, rs2637988 was in linkage disequilibrium with the VNTR (D′ = 0.90). A haploblock of VNTR*2 and the minor alleles of rs408392and rs419598 was constructed. Meta-analysis revealed that this VNTR*2 haploblock is associated with IPF susceptibility both with an allelic model (odds ratio = 1.42, p = 0.002) and a carriership model (odds ratio = 1.60, p = 0.002). IL1RN mRNA expression was significantly influenced by rs2637988, with lower levels found in carriers of the (minor) GG genotype (p < 0.001). From this meta-analysis, we conclude that the VNTR*2 haploblock is associated with susceptibility to IPF. In addition, polymorphisms in IL1RN influence IL-1Ra mRNA expression, suggesting that lower levels of IL-1Ra predispose to developing IPF. Together these findings demonstrate that the cytokine IL-1Ra plays a role in IPF pathogenesis.     

Evaluation of blood antioxidant defense and apoptosis in peripheral lymphocytes on exogenous administration of pineal proteins and melatonin in rats

In view of the significant health impact of oxidative stress and apoptosis dysfunction, and further, because of suggestions that administration of antioxidants might reduce apoptosis rate through up-regulation of body antioxidant defense systems, therefore the purpose of this study was to compare the effect of buffalo (Bubalus bubalis) pineal proteins (PP at 100 μg/kg BW, i.p.) with melatonin (MEL at 10 mg/kg BW, i.p.) on blood (erythrocytes) antioxidant defense system and apoptosis in isolated peripheral blood lymphocytes of female Wistar albino rats. The cell viability index (%) and apoptosis index (%), which are directly related to the apoptosis rate of the cells, were used as dependent measures for inferring PP and MEL activity. The total cell viability index did not differ between rats treated with MEL and PP from control animals. The percentage of apoptotic cell death through fluorescence microscopy also did not change in MEL and PP groups as compared with control. DNA fragmentation as an index of apoptosis was detected with propidium iodide staining and assessed by flow cytometry. Pineal proteins and MEL administration caused significant (p < 0.05) reduction in lipid peroxidation and increased level of catalase, superoxide dismutase, glutathione peroxidase, and glutathione in erythrocytes as compared with control. Interestingly, we did not observe increase in the non-viable cells and percentage of apoptotic cell death in PP-treated group, controls or in animals in which MEL had been administered. Therefore, the present study confirmed the up-regulation of erythrocytes (blood) antioxidant defense systems and absence of adverse effect on rate of apoptosis in PP and MEL-administered rats under absence of stress or toxicant exposure. Hence, these test agents can be tested for further therapeutic values against adverse apoptosis rate under stress or toxicants exposures.     

Isocyanates induces DNA damage,apoptosis, oxidative stress,and inflammation in cultured human lymphocytes

Isocyanates, a group of low molecular weight aromatic and aliphatic compounds containing the isocyanate group (?NCO), are important raw materials with diverse industrial applications; however, pathophysiological implications resulting from occupational and accidental exposures of these compounds are hitherto unknown. Although preliminary evidence available in the literature suggests that isocyanates and their derivatives may have deleterious health effects including immunotoxicity, but molecular mechanisms underlying such an effect have never been addressed. The present study was carried out to assess the immunotoxic response of methyl isocyanate (MIC) on cultured human lymphocytes isolated from healthy human volunteers. Studies were conducted to evaluate both dose‐dependent and time‐course response (n = 3), using N‐succinimidyl N‐methylcarbamate, a surrogate chemical substitute to MIC. Evaluation of DNA damage by ataxia telangiectasia mutated (ATM) and γ H2AX protein phosphorylation states; measure of apoptotic index through annexin‐V/PI assay, apoptotic DNA ladder assay, and mitochondrial depolarization; induction of oxidative stress by CM‐H2DCFDA and formation of 8‐hydroxy‐2′ deoxy guanosine; levels of antioxidant defense system enzyme glutathione reductase; and multiplex cytometric bead array analysis to quantify the secreted levels of inflammatory cytokines, interleukin‐8, interleukin‐1β, interleukin‐6, interleukin‐10, tumor necrosis factor, and interleukin‐12p70 parameters were carried out. The results of the study showed a dose‐ and time‐dependent response, providing evidence to hitherto unknown molecular mechanisms of immunotoxic consequences of isocyanate exposure at a genomic level. We anticipate these data along with other studies reported in the literature would help to design better approaches in risk assessment of occupational and accidental exposure to isocyanates. © 2008 Wiley Periodicals, Inc. J Biochem Mol Toxicol 22:429–440, 2008; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/jbt.20260     

Radioprotective effect of geraniin via the inhibition of apoptosis triggered by γ-radiation-induced oxidative stress

The radioprotective effect of geraniin, a tannin compound isolated from Nymphaea tetragona Georgi var. (Nymphaeaceae), against γ-radiation-induced damage was investigated in Chinese hamster lung fibroblast (V79-4) cells. Geraniin recovered cell viability detected by MTT test and colony formation assay, which was compromised by γ-radiation, and reduced the γ-radiation-induced apoptosis by the inhibition of loss of the mitochondrial membrane potential. Geraniin protected cellular components (lipid membrane, cellular protein, and DNA) damaged by γ-radiation, which was detected by lipid peroxidation, protein carbonyl formation, and comet assay. Geraniin significantly reduced the level of intracellular reactive oxygen species generated by γ-radiation, which was detected using spectrofluorometer, flow cytometer, and confocal microscope after 2′,7′-dichlorodihydrofluorescein diacetate staining. Geraniin normalized the superoxide dismutase and catalase activities, which were decreased by γ-radiation. These results suggest that geraniin protects cells against radiation-induced oxidative stress via enhancing of antioxidant enzyme activities and attenuating of cellular damage.     

Sodium Tungstate Attenuate Oxidative Stress in Brain Tissue of Streptozotocin-Induced Diabetic Rats

High blood glucose concentration in diabetes induces free radical production and, thus, causes oxidative stress. Damage of cellular structures by free radicals play an important role in development of diabetic complications. In this study, we evaluated effects of sodium tungstate on enzymatic and nonenzymatic markers of oxidative stress in brain of streptozotocin (STZ)-induced diabetic rats. Rats were divided into four groups (ten rats in each group): untreated control, sodium tungstate-treated control, untreated diabetic, and sodium tungstate-treated diabetic. Diabetes was induced with an intraperitoneal STZ injection (65 mg/kg body weight), and sodium tungstate with concentration of 2 g/L was added to drinking water of treated animals for 4 weeks. Diabetes caused a significant increase in the brain thiobarbituric acid reactive substances (P < 0.01) and protein carbonyl levels (P < 0.01) and a decrease in ferric reducing antioxidant power (P < 0.01). Moreover, diabetic rats presented a reduction in brain glucose-6-phosphate dehydrogenase (21%), superoxide dismutase (41%), glutathione peroxidase (19%), and glutathione reductase (36%) activities. Sodium tungstate reduced the hyperglycemia and restored the diabetes-induced changes in all mentioned markers of oxidative stress. However, catalase activity was not significantly affected by diabetes (P = 0.4), while sodium tungstate caused a significant increase in enzyme activity of treated animals (P < 0.05). Data of present study indicated that sodium tungstate can ameliorate brain oxidative stress in STZ-induced diabetic rats, probably by reducing of the high glucose-induced oxidative stress and/or increasing of the antioxidant defense mechanisms.     

Antioxidant Properties of Selected <Emphasis Type="Italic">Boletus</Emphasis> Mushrooms

Considering the growing interest for mushrooms and the demand search of natural antioxidants sources, the aim of this study was to investigate the antioxidant properties of two edible widely used Boletus species, Boletus edulis, and Boletus auranticus, collected from Istra region in Croatia in late summer 2007. To evaluate the antioxidant properties and content of antioxidant compounds, scavenging capacity on DPPH˙, OH˙, and O₂˙⁻ radicals, reducing power and capacity to inhibit lipid peroxidation has been investigated. It is determined that content of total phenols (41.82 ± 0.08 mg gallic acid equivalent per gram of dry extract) was higher for B. edulis. Using high performance liquid chromatography/diode array detector analysis, the main antioxidant compound, variegatic acid, has been detected and quantified. 1,1-Diphenyl-2-picryl-hydrazyl-hydrate assay was used as a preliminary free radical–scavenging evaluation. By this assay, it has been found that B. edulis dry mushroom extract exhibits 50% of inhibition value at the extract concentration of 0.016 ± 0.0003 mg/ml. The extracts were capable of reducing iron(III) and, thus, are capable of donating electrons. Using electron paramagnetic resonance spin-trapping and spin-probing techniques, activity against relevant reactive species, ˙OH and O₂˙⁻ radical, was analyzed for both mushroom extracts. Both investigated extracts are determined as good inhibitors for ˙OH radical reduction, and both exhibited significant capacity for scavenging O₂˙⁻ radical and for that could help to prevent or meliorate oxidative damage. Only B. edulis extract prevents lipid peroxidation. Investigated mushroom extracts could represent easily accessible natural antioxidant resource.     

Response of plasma IL-6 and its soluble receptors during submaximal exercise to fatigue in sedentary middle-aged men

The pleiotropic cytokine interleukin-6 (IL-6) has been demonstrated to increase during exercise. Little is known regarding the response of the soluble IL-6 receptors (sIL-6R and sgp130) during such exercise. The aim of the current study was to investigate the response of plasma IL-6, sIL-6R and sgp130 during fatiguing submaximal exercise in humans. Twelve participants underwent an incremental exercise test to exhaustion and one week later performed a submaximal exercise bout (96 ± 6% lactate threshold) to volitional exhaustion. Blood samples taken at rest and immediately post exercise were analyzed for IL-6, sIL-6R and sgp130. IL-6 increased (P < 0.01) by 8.4 ± 8.9 pg ml⁻¹ (75.7%) during the exercise period. sIL-6R and sgp130 also increased (P < 0.05) by 2.7 ± 3.9 ng ml⁻¹ (9.6%) and 37.7 ± 55.6 ng ml⁻¹ (9.6%), respectively. The current study is the first investigation to demonstrate that alongside IL-6, acute exercise stress results in an increase in both sIL-6R and sgp130.