The effect of combinations of Fusarium mycotoxins (deoxynivalenol, zearalenone and fumonisin B1) on growth of brewing yeasts

The interactive effect of combinations of the Fusarium mycotoxins deoxynivalenol (DON), zearalenone (ZEA) and fumonisin B1 (FB1) on growth of brewing yeasts was examined. Yeast growth was assessed by measurement of dry weight or relative growth, cell number, viability and conductance change of the growth medium using direct and indirect methods. The interactive effect of a combination of these mycotoxins was subject to the ratio of toxins in the mixture and the toxicity of individual toxins on yeast growth. When a combination of mycotoxins at low concentration was added into the growth medium, no significant inhibitory effect on growth was observed compared to controls. However, when a combination of high concentrations of DON and ZEA which individually inhibited yeast growth was examined, the interactive effect was shown to pass from antagonism to synergism depending on the ratio of the toxins in the mixture. As a synergistic interaction between these Fusarium mycotoxins was observed only at high concentrations, which were far higher than would be expected in good quality grain, they are not a concern when related to yeast growth under the brewing conditions studied.     

Pulmonary antioxidant defences and protein damage during the ageing process of both sexes

The free radical theory holds that the senescence is caused by oxidative damage that results from an imbalance between reactive oxygen and nitrogen species (RONS) and antioxidant defences. Hence, it plays an important role in the field of gerontology. We evaluated, in male and female rats, the activities of the antioxidant enzymes catalase (CAT), glutathione peroxidase (GPx), and total superoxide dismutase (tSOD), as well as oxidative protein damage in pulmonary tissue at 3, 6, 12, and 20 months of age. The results show an increase in the activities of all antioxidant enzymes at 12 months of age in female rats, suggesting an association with the reproductive life cycle. Protein damage in female pulmonary tissues did not change significantly throughout the ageing process. In male rats, the activity of GPx in 20 months of age showed an inter‐gender increase, while the tSOD and GPx showed higher activities in 20 months of age in the intra‐gender analysis. The male lung showed higher protein damage at 6 months of age. These findings suggest that antioxidant enzymatic activity is connected to the reproductive life cycle. Copyright © 2009 John Wiley & Sons, Ltd.     

Effects of beta-carboline alkaloids on the object recognition task in mice

beta-carboline alkaloids are found in several medicinal plants and display a variety of actions on the central nervous, muscular and cardiovascular systems. The aim of the present study was to evaluate the effects of systemic administration of beta-carboline alkaloids on object recognition in mice. Adult Swiss mice received an intra-peritoneal injection (i.p.) of alkaloids (1.0, 2.5 or 5.0 mg/kg) 30 min before training in an object recognition task. The fully aromatic beta-carbolines, harmine and harmol, induced an enhancement of short-term memory (STM) at all doses tested when compared to controls. Harmaline, a dihydro beta-carboline and inverse agonist of the MK-801 binding site on the N-methyl-d-aspartate (NMDA) receptor, also induced an enhancement of both short-term memory (STM) and long-term memory (LTM). These results demonstrate that systemic administration of beta-carboline alkaloids can improve object recognition memory in mice.     

Determination of moniliformin using SAX column clean-up and HPLC/DAD-detection

This work describes a method for the determination of theFusarium mycotoxin moniliformin (MON) in cereals. In addition to the optimization of the clean-up and the HPLC determination the most efficient extraction mode was investigated on natural contaminated samples. The method was validated for maize and wheat using a calibration range from 57 to 2300 μg/kg. Due to the ionic nature of the toxin the clean-up of the extracts was carried out with strong-anion-exchange columns. Moniliformin was separated by reversed phase ion-pair-chromatography (RP-Ion pair-HPLC) and detected by DAD. The validated method yielded recoveries of 76%±9% (maize) and 87%±5% (wheat) and detection limits of 39 μg/kg and 30 μg/kg, respectively. The suitability of the developed method was demonstrated on natural contaminated samples. Presented at the 25^th Mykotoxin Workshop in Giessen, Germany, May 19–21, 2003     

Response to Oxidative Stress in Eight Pathogenic Yeast Species of the Genus <Emphasis Type="Italic">Candida</Emphasis>

In the course of an infection, the formation of reactive oxygen species by phagocytes and the antioxidant defense mechanisms of microorganisms play a crucial role in pathogenesis. In this study, isolates representing 8 pathogenic Candida species—Candida albicans, Candida dubliniensis, Candida famata, Candida glabrata, Candida guilliermondii, Candida krusei, Candida parapsilosis and Candida tropicalis—were compared with regard to their resistance to oxidative stress in vitro. We evaluated degree of resistance, induction of oxidative damage, capacity to adapt, and induction of antioxidant enzymes. The species showed variable sensitivity to oxidative attack. C. albicans, C. glabrata, and C. krusei were more resistant to oxidative stress under the conditions tested; C. parapsilosis and C. tropicalis presented medium resistance; and C. dubliniensis, C. famata, and C. guilliermondii were more sensitive. The overall greater resistance to oxidative stress of C. albicans and C. glabrata may provide an advantage to these species, which are the major causative agents of candidiasis.     

Activation of Brain Indoleamine-2,3-dioxygenase Contributes to Depressive-Like Behavior Induced by an Intracerebroventricular Injection of Streptozotocin in Mice

Neurochemical Research - There is a lack of information concerning the molecular events underlying the depressive-like effect of an intracerebroventricular injection of streptozotocin (ICV-STZ) in...     

Hepatoprotective effect of bis(4‐methylbenzoyl) diselenide against CCl4‐induced oxidative damage in mice

From a pharmacological point of view, organoseleniums are compounds with important and interesting antioxidant and biological activities. The aim of this study was to evaluate the hepatoprotective effect of bis(4‐methylbenzoyl) diselenide (BMD) against carbon tetrachloride (CCl₄)–induced oxidative damage in mice. The animals received BMD (25 mg/kg p.o., for 3 days), and after 1 day, CCl₄ (1 mg/kg body weight) was administered by intraperitoneal route. One day after the CCl₄ exposure, the animals were euthanized for biochemical and histological analysis. Treatment with BMD (25 mg/kg p.o.) protected against aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase, gamma‐glutamyl transferase and lactate dehydrogenase activity increases induced by CCl₄ plasma exposure. Treatment with BMD (25 mg/kg) protected against increases in thiobarbituric reactive species and decreasing non‐protein thiols and ascorbic acid levels in liver of mice. Catalase and superoxide dismutase activity inhibition in the liver caused by CCl₄ were protected by treatment with BMD (25 mg/kg). Glutathione S‐transferase activity was inhibited by CCl₄ and remained unaltered even after treatment with BMD. Sections of liver from CCl₄‐exposed mice presented an intense infiltration of inflammatory cells and loss of the cellular architecture. BMD (25 mg/kg) attenuated CCl₄‐induced hepatic histological alterations. The results demonstrated the hepatoprotective effects of BMD in the mouse liver, possibly by modulating the antioxidant status. Copyright © 2012 John Wiley & Sons, Ltd.