Eszter Horváth

Regulation of patulin-induced oxidative stress processes in the fission yeast Schizosaccharomyces pombe.

Patulin (PAT), is one of the most widely disseminated mycotoxins found in agricultural products. In this study the PAT-induced accumulation of reactive oxygen species (ROS) and the regulation of the specific activities of antioxidant enzymes were investigated in the single cell eukaryotic organism Schizosaccharomyces pombe. In comparison with the untreated cells, 500 μM PAT treatment caused a 43% decrease in the concentration of the main intracellular antioxidant, glutathione (GSH); this depletion of GSH initiated a 2.44- and a 2.6-fold accumulation of superoxide anion and hydrogen peroxide, respectively, but did not increase the concentration of hydroxyl radicals; the reduction of ROS-induced adaptation processes via the activation of Pap1 transcription factor resulted in significantly increased specific activities of Cu/Zn superoxide dismutase, catalase and glutathione S-transferase to protect the cells against the ROS-induced unbalanced redox state. However, no change was measured in the activities of glutathione reductase, glutathione peroxidase and glucose-6-phosphate dehydrogenase. It seems reasonable to assume that the temporary PAT-induced ROS accumulation plays a crucial role in adaptation processes. The adverse effects of PAT may be exerted mainly through the destruction of cellular membranes and protein/enzyme functions.

Comparative Assessment of the Mussel Micronucleus Test Versus Bacterial Bioassays for Genotoxicity Testing of Benzo[a]pyrene

Polycyclic aromatic hydrocarbons are hazardous compounds to the environment and human health, thus their detection is an important task. In this study the genotoxic effect of benzo[a]pyrene (B[a]P) was examined on a freshwater mussel Unio pictorum and results were compared to bacterial tests, such as the Ames test and SOS chromotest. The aim of the study was to calibrate the sensitivity of the mussel micronucleus test to that of the two bacterial tests using B[a]P as a reference chemical. The Ames and the micronucleus tests gave similar response both in sensitivity and in concentrationresponse pattern. These two tests are proposed to be applied in a battery for genotoxicity testing.

Genotoxic effect of Lythrum salicaria extract determined by the mussel micronucleus test.

A wide range of aquatic plants have been proven to release allelochemicals, of them phenolics and tannin are considered rather widely distributed. Tannins, however, have been demonstrated to have genotoxic capacity. In our study genotoxic potential of Lythrum salicaria L. (Purple Loosestrife, family Lythraceae) was assessed by the mussel micronucleus test, using Unio pictorum. In parallel, total and hydrolysable tannin contents were determined. Results clearly show that the extract had a high hydrolysable tannin content and significant mutagenic effect. As L. salicaria has been long used in traditional medicine for chronic diarrhoea, dysentery, leucorrhoea and blood-spitting, genotoxic potential of the plant should be evaluated not only with regard to potential effects in the aquatic ecosystem, but also assessing its safe use as a medicinal herb.

Eco- and genotoxicity profiling of a rapeseed biodiesel using a battery of bioassays

Biodiesel is considered an important renewable energy source but still there is some controversy about its environmental toxicity, especially to aquatic life. In our study, the toxicity of water soluble fraction of biodiesel was evaluated in relatively low concentrations using a battery of bioassays: Vibrio fischeri bioluminescence inhibition, Sinapis alba root growth inhibition, Daphnia magna immobilization, boar semen live/dead ratio and DNA fragmentation and Unio pictorum micronucleus test. While the S. alba test indicated nutritive (stimulating) effect of the sample, the biodiesel exerted toxic effect in the aquatic tests. D. magna was the most sensitive with EC50 value of 0.0226%. For genotoxicity assessment, the mussel micronucleus test (MNT) was applied, detecting considerable genotoxic potential of the biodiesel sample: it elucidated micronuclei formation already at low concentration of 3.3%. Although this test has never been employed in biodiesel eco/genotoxicity assessments, it seems a promising tool, based on its appropriate sensitivity, and representativity.

Assessment of the credibility of public websites about medicinal herbs

In recent decades, there has been a growing interest in the use of herbs and herbal medicinal products, both in developing and developed countries. While electronic medium has become a more and more important tool for presenting information about health-related issues, several studies demonstrated that the internet often contains inaccurate and/or misleading information. In our study we assessed 30 Hungarian websites and 2 cellphone applications intended for public use and evaluated the quality and credibility of the information presented about medicinal plants recommended. It was found that websites showed very diverse safety: most websites gave mixed information, that is, some medicinal herbs and their potential hazard were properly described, while others were not. There were, however, websites, which completely missed to give information about any potential hazard. As credibility of public websites can be in most cases questioned, it is strongly recommended for potential users to consult more than one source of information.

Adapting the Vegetative Vigour Terrestrial Plant Test for assessing ecotoxicity of aerosol samples

Plants, being recognized to show high sensitivity to air pollution, have been long used to assess the ecological effects of airborne contaminants. However, many changes in vegetation are now generally attributed to atmospheric deposition of aerosol particles; the dose–effect relationships of this process are usually poorly known. In contrast to bioindication studies, ecotoxicological tests (or bioassays) are controlled and reproducible where ecological responses are determined quantitatively. In our study, the No. 227 OECD Guideline for the Testing of Chemicals: Terrestrial Plant Test: Vegetative Vigour Test (hereinafter referred to as ‘Guideline’) was adapted and its applicability for assessing the ecotoxicity of water-soluble aerosol compounds of aerosol samples was evaluated. In the aqueous extract of the sample, concentration of metals, benzenes, aliphatic hydrocarbons and PAHs was determined analytically. Cucumis sativus L. plants were sprayed with the aqueous extract of urban aerosol samples collected in a winter sampling campaign in Budapest. After the termination of the test, on day 22, the following endpoints were measured: fresh weight, shoot length and visible symptoms. The higher concentrations applied caused leaf necrosis due to toxic compounds found in the extract. On the other hand, the extract elucidated stimulatory effect at low concentration on both fresh weight and shoot length. The test protocol, based on the Guideline, seems sensitive enough to assess the phytotoxicity of aqueous extract of aerosol and to establish clear cause–effect relationship.

Microbiological characterization of stable resuspended dust

OBJECTIVES Air quality in the stables is characterized by elevated level of dust and aeroallergens which are supposed to directly cause or exacerbate several respiratory disorders. The most often recognized problem is recurrent airway obstruction (RAO), previously known as chronic obstructive pulmonary disease (COPD). There is some indication that aeroallergens (among them endotoxins) may also cause inflammation in human airways and may exceed safe levels in stables. Monitoring studies have covered mainly the determination of the concentration of respirable particles and of culturable fungi and their toxins. However, these particles do not only directly affect the respiratory system, but might act as a carrier conveying toxic contaminants and biological agents such as bacteria. In a typical, 20-horse Hungarian stable, microbial community of respirable fraction of resuspended dust has been characterized to reveal if these particles convey hazardous pathogenic bacteria, posing risk to either horses or staff. MATERIAL AND METHODS Resuspended dust was sampled using a mobile instrument. The instrument contains a PARTISOL-FRM model 2000 sampler that was operated at a flow rate of 16.7 l/min and a cyclone separator which collected the particulate matter with an aerodynamic size between 1 μm and 10 μm (PM1-10) fraction. Microbial taxa were identified by culture-independent next generation sequencing (NGS) of variable 16S ribosomal ribonucleic acid (rRNA) gene regions. RESULTS In total, 1491 different taxa were identified, of them 384 were identified to species level, 961 to genus level. The sample was dominated by common ubiquitous soil and organic material-dwelling taxa. CONCLUSIONS Pathogens occurred at low abundance, and were represented by mostly facultative human pathogens, with the prevalence of Staphylococcus species.

Geno- and cytotoxicologic assessment of wastewater effluents with mussel micronucleus assay and with flow cytometric sperm toxicity assay: a comparison

Several pharmaceutical drugs have potential harmful effect on wildlife such as aquatic toxicity, genotoxicity, or endocrine disruption effect. Removal rates of pharmaceuticals from municipal sewage during waste water treatment is questionable, several studied drugs are insufficiently or not removed while passing through the sewage treatment plants (STP).The analytical monitoring of potentially harmful drugs and especially drug residues in influent and effluent of STP are rather costly and not always possible on a day to day basis. Toxicity bioassays, on the other hand, are relatively cost-effective short-term tests, estimating the aggregate genotoxicity of the samples on different taxonomic levels. In our study the cytoand genotoxicity of the pre-treated potentially pharmaceutical containing influent and the effluent sample of a Hungarian STP were estimated with mussel (Unio pictorum) micronucleus (MN) assay and flow cytometric boar spermatozoa assay. The influent induced in the flow cytometric assay significant changes in mitochondrial transmembrane potential, oxidative DNA lesions and DNA fragmentation, but no significant genotoxic effect was detected by the MN assay. These results point to deficiencies of present wastewater treatment systems and remind us to choose carefully among available toxicity assays. Keywords— genotoxicity, cytotoxicity, pharmaceutical sewage, micronucleus assay, flow cytometric spermatozoa assay

Assessment of municipal wastewater genotoxicity using the Ames fluctuation test, the SOS Chromotest and the mussel micronucleus test: a comparison

Municipal wastewaters may contain a variety of genotoxic compounds, including drugs or their metabolites, PAHs, etc. Bacterial genotoxicity assays use DNA impairment as end point while micronucleus tests, conducted on eucaryotes, assess chromosome aberrations. As relatively few comparative studies exist, in this study results of the micronucleus test using the painter’s mussel (Unio pictorum) are compared to those of two bacterial assays, the Ames test and the SOS Chromotest. Both the Ames test and the micronucleus test showed clear concentration-response pattern, however, the Ames test proved more sensitive. Of the two bacterial assays, the SOS Chromotest gave positive result only for the most concentrated sample. Keywords—municipal wastewater, genotoxicity, mussel micronucleus test, Ames test, SOS Chromotest