Determination of the mycotoxin zearalenone in water by immunofluorescence and total internal reflection ellipsometry methods

In the scope of project Aquafluosense developing prototypes of fluorescence-based instrumentation for in situ measurement of several characteristic parameters of water quality, an immunofluorescent method have been developed for the detection of several environmental xenobiotics, including mycotoxin zearalenone (ZON). ZON, produced by several plant pathogenic Fusarium species, has recently been identified as an emerging pollutant in surface water, presenting a hazard to aquatic ecosystems. Due to its physico-chemical properties, detection of ZON at low concentration in surface water is a challenging task. The 96-well microplate-based fluorescent instrument is capable to detect ZON in the concentration range of 0.4–400 ng mL-1 . The sensitivity and accuracy of the analytical methods has been demonstrated by comparative assessment with detection by total internal reflection ellipsometry

A fotoakusztikus spektroszkópia (PÁS) alkalmazási lehetősége az élelmiszeripari nyers- és adalékanyagok minősítésében

A fotoakusztikus spektroszkópia a 70-es években fejlődött ki és különösen olyan területeken terjedt el, ahol a minta felületétől távolabbi rétegekből is szükség van az anyagszerkezetre utaló információra. Ilyen terület pl. a növényi hisztológia, de kézenfekvő alkalmazási területnek látszik az élelmiszertudomány is. A BME Atomfizikai Tanszékén a KÉKI-vel közösen kifejlesztett fotoakusztikus spektroszkóppal végzett mérésekről, Rodamin—B, különböző vizes higítású tejoldatok, burgonya- és búzakeményítő PA-spektrumának vizsgálatáról számol be a közlemény. Photoacoustic spectroscopy has been developed in the seventies and was spread in fields which need information concerning material structure of layers further from sample surface, too. Plant histology is one of them, and food science also seems to be a possible field. The article reports on measurements performed with a photoacoustic spectroscope developed in the Department of Nuclear Physics of Technical University of Budapest in cooperation with Central Food Research Institute. The PAS spectra of the following substances were investigated: Rhodamin В, aqueous milk solutions in different dilutions, potato and wheat starch. Die photoakustische Spektroskopie wurde in den 70 er Jahren entwickelt und wird insbesondere auf solchen Gebieten angewandt, wo Informationen über die Materialstuktur nicht nur von der Oberfläche der Probe, sondern auch von tieferen Schichten benötigt werden. Ein solches Gebiet ist z.B. die pflanzliche Hystologie, aber auch die Lebensmittelwissenschaft kann als ein geegnetes Anwendungsgebiet angesehen werden. Im vorliegenden Artikel werden über die mit dem am Lehrstuhl für Atomphysik der Technischen Universität Budapest gemeinsam mit dem Zentralinstitut für Lebensmittelforschung entwickelten photoakustischen Spektroskop durchgeführten Messungen und über die Untersuchungen des PA-Spektrums von Rodamin—B, verschiedener wäßriger Verdünnungen von Milchlösungen sowie Kartoffeln und Weizenstärke berichtet

Application of an induced fluorometry-based method in algal growth inhibition tests

Aquatic ecosystems are strongly exposed to various micropollutants from agricultural origin. The harmful effect can be expressed directly on aquatic organisms and indirectly through the food chain. The use of ecotoxicity assays mainly in aquatic environments, and corresponding water quality assessment are undoubtedly important. Project Aquafluosense was designed to develop instrument prototypes of a fluorescence-based setup for in situ measurement of algal biomass and for application of flurescence in ecotoxicity assays. Fluorescence-based determination of algal density was validated by conventional methods and signals obtained by the fluorometer correlated well with the conventional methods for algal density determination. The applicability of the fluorometer developed was demonstrated in ecotoxicity assays using the herbicide active ingredient isoxaflutole in neat and formulated forms

Chlorophyll fluorescence instrumentation for a rapid, in situ measurement of algal density

In the project reported, we are developing an instrument for measuring algal density based on the detection of chlorophyll fluorescence. Following the adjustment of several parameters defined during preliminary analyses, measurements were made on different concentrations of model green and blue algal cultures. Fluorescent signal intensities measured by the prototypes of the fluorometer module were compared to values determined by other, widely used methods for estimation of algal density (i.e. Bürker chamber cell counting, optical density measurement and chlorophyll-a measurement with ethanol extraction method). Fluorometer results correlated well with the other methods, resulting high correlation coefficients (R2>0.9%). Limits of detection and limits of quantification showed a decreasing trend during the development phases resulting in a highly sensitive instrument

Development of an immunofluorescence assay module for determination of the mycotoxin zearalenone in water

Project Aquafluosense is designed to develop prototypes for a fluorescence-based instrumentation setup for in situ measurements of several characteristic parameters of water quality. In the scope of the project an enzyme-linked fluorescent immunoassay (ELFIA) method has been developed for the detection of several environmental xenobiotics, including mycotoxin zearalenone (ZON). ZON, produced by several plant pathogenic Fusarium species, has recently been identified as an emerging pollutant in surface water, presenting a hazard to aquatic ecosystems. Due to its physico-chemical properties, detection of ZON at low concentrations in surface water is a challenging task. The 96-well microplate-based fluorescence instrument is capable of detecting ZON in the concentration range of 0.09–400 ng/mL. The sensitivity and accuracy of the analytical method has been demonstrated by a comparative assessment with detection by high-performance liquid chromatography and by total internal reflection ellipsometry. The limit of detection of the method, 0.09 ng/mL, falls in the low range compared to the other reported immunoassays, but the main advantage of this ELFIA method is its efficacy in combined in situ applications for determination of various important water quality parameters detectable by induced fluorimerty—e.g., total organic carbon content, algal density or the level of other organic micropollutants detectable by immunofluorimetry. In addition, the immunofluorescence module can readily be expanded to other target analytes if proper antibodies are available for detection

Advanced Multi-Color Fluorescence Imaging System for Detection of Biotic and Abiotic Stresses in Leaves

The autofluorescence of a sample is a highly sensitive and selective optical property and gives the possibility to establish non-destructive techniques of the investigation of plants, like detecting the chlorophyll fluorescence related to stress phenomena. In this study, an advanced multi-color fluorescence imaging system and data analysis were presented. The advantage of an imaging system is the additional receiving of spatial information over a sample area, this is a strong improvement compared to spot measurements commonly used. The purpose was to demonstrate the possibility of the detection and characterization of stress symptoms using this system. Specific fluorescence ratios were identified to characterize the stress status over the whole leaf, here shown on barley grown under different nitrogen supply (abiotic stress). Due to the changes, it is possible to make conclusions about leaf pigments (chlorophylls and phenolics) related to stress response. The second aim was to use the shape of local symptoms (biotic stress) as a criterion. For this purpose, three structural different kinds of fungal symptoms were analyzed using shape descriptors. It shows that an additional image shape analysis can be very useful for extracting further information, in this case the successful discrimination of fungal infections

Development of an Immunofluorescent Capillary Sensor for the Detection of Zearalenone Mycotoxin

A capillary-based immunofluorescence sensor was developed and incorporated in a flow injection analysis system. The light-guiding capillary was illuminated axially by a 473 nm/5 mW solid state laser through a tailored optofluidic connector. High sensitivity of the system was achieved by efficiently collecting and detecting the non-guided fluorescence signal scattered out along the wall of the capillary. The excitation was highly suppressed with bandpass and dichroic filters by simultaneously exploiting the guiding effect inside the capillary. The glass capillary used as a measuring cell was silanized in liquid phase by 3-aminopropyltriethoxysilane (APTS), and the biomolecules were immobilized using glutaraldehyde inside the capillary. The applicability of the developed system was tested with a bovine serum albumin (BSA)—anti-BSA-IgG model-molecule pair, using a fluorescently labeled secondary antibody. Based on the results of the BSA–anti-BSA experiments, a similar setup using a primary antibody specific for zearalenone (ZON) was established, and a competitive fluorescence measurement system was developed for quantitative determination of ZON. For the measurements, 20 µg/mL ZON-BSA conjugate was immobilized in the capillary, and a 1:2500 dilution of the primary antibody stock solution and a 2 µg/mL secondary antibody solution were set. The developed capillary-based immunosensor allowed a limit of detection (LOD) of 0.003 ng/mL and a limit of quantification (LOQ) of 0.007 ng/mL for ZON in the competitive immunosensor setup, with a dynamic detection range of 0.01–10 ng/mL ZON concentrations

ENGINEERING GEOLOGICAL SURVEY OF RÓZSADOMB AREA, BUDAPEST, HUNGARY

Late Triassic platform and extensional basinal sediments and Eocene shallow self carbonates are mainly covered by Oligocene clays, Pleistocene-Holocene slope sediments in the Rózsadomb area. Eocene carbonates are the host rocks of the extended (25 km) cave system, which passages are primarily tectonically controlled. The fractures and joints of the three major tectonic phases vvere enlarged by ascending thermal waters in the Plio-Pleistocene period. The presence of near surface cave passages raises special problems: hazards of cave collapse, especially when the cover beds are fractured Eocene marls; pollution of karst and related thermal water system from failure of sewer system or cesspits via fissures and cave passages. Damages in built environment are mainly related to landslides of the soaked clayey slope sediments, since in the deeper zones the 'solid' carbonate rocks are stable. The major trigger mechanism of the landslides is the precipitation combined with slope instability (human activity). To reduce the risk of landslides, damages and contaminations the reconstruction and extension of sewer system; the stricter regulations of human impact (control of townplanning regulations); the extension of protection zones and the exploration of the unknown cave system would be necessary

Hormesis, the Individual and Combined Phytotoxicity of the Components of Glyphosate-Based Formulations on Algal Growth and Photosynthetic Activity

The occurrence of the market-leading glyphosate active ingredient in surface waters is a globally observed phenomenon. Although co-formulants in pesticide formulations were considered inactive components from the aspects of the required main biological effect of the pesticide, several studies have proven the high individual toxicity of formulating agents, as well as the enhanced combined toxicity of the active ingredients and other components. Since the majority of active ingredients are present in the form of chemical mixtures in our environment, the possible combined toxicity between active ingredients and co-formulants is particularly important. To assess the individual and combined phytotoxicity of the components, glyphosate was tested in the form of pure active ingredient (glyphosate isopropylammonium salt) and herbicide formulations (Roundup Classic and Medallon Premium) formulated with a mixture of polyethoxylated tallow amines (POEA) or alkyl polyglucosides (APG), respectively. The order of acute toxicity was as follows for Roundup Classic: glyphosate < herbicide formulation < POEA. However, the following order was demonstrated for Medallon Premium: herbicide formulation < glyphosate < APG. Increased photosynthetic activity was detected after the exposure to the formulation (1.5–5.8 mg glyphosate/L and 0.5–2.2 mg POEA/L) and its components individually (glyphosate: 13–27.2 mg/L, POEA: 0.6–4.8 mg/L), which indicates hormetic effects. However, decreased photosynthetic activity was detected at higher concentrations of POEA (19.2 mg/L) and Roundup Classic (11.6–50.6 mg glyphosate/L). Differences were demonstrated in the sensitivity of the selected algae species and, in addition to the individual and combined toxicity of the components presented in the glyphosate-based herbicides. Both of the observed inhibitory and stimulating effects can adversely affect the aquatic ecosystems and water quality of surface waters

Ecotoxicological Evaluation of Safener and Antimicrobial Additives in Isoxaflutole-Based Herbicide Formulations

The environmental load by isoxaflutole and its formulated herbicide products has increasingly become apparent because, after the ban of atrazine, isoxaflutole has become its replacement active ingredient (a.i.). Obtaining information regarding the fate of this a.i. in environmental matrices and its ecotoxicological effects on aquatic organisms is essential for the risk assessment of the herbicide. In this study, the effects of Merlin Flexx- and Merlin WG75 formulated isoxaflutole-based herbicide products and two selected additives (cyprosulfamide safener and 1,2-benzisothiazol-3(2H)-one antimicrobial agent) were investigated on Raphidocelis subcapitata in growth inhibition assays. In ecotoxicological tests, two conventional (optical density and chlorophyll-a content) and two induced fluorescence-based (Fv*/Fp: efficiency of the photosystem PSII and Rfd* changes in the observed ratio of fluorescence decrease) endpoints were determined by UV-spectrophotometer and by our FluoroMeter Module, respectively. Furthermore, dissipation of isoxaflutole alone and in its formulated products was examined by an HPLC-UV method. In ecotoxicological assays, the fluorescence-based Rfd* was observed as the most sensitive endpoint. In this study, the effects of the safener cyprosulfamide and the antimicrobial agent 1,2-benzisothiazol-3(2H)-one on R. subcapitata is firstly reported. The results indicated that the isoxaflutole-equivalent toxicity of the mixture of the isoxaflutole–safener–antimicrobial agent triggered lower toxicity (EC50 = 2.81 ± 0.22 mg/L) compared to the individual effect of the a.i. (EC50 = 0.02 ± 0.00 mg/L). The Merlin Flexx formulation (EC50 = 27.04 ± 1.41 mg/L) was found to be approximately 50-fold less toxic than Merlin WG75, which can be explained by the different chemical characteristics and quantity of additives in them. The additives influenced the dissipation of the a.i. in Z8 medium, as the DT50 value decreased by approximately 1.2- and 3.5-fold under light and dark conditions, respectively