s/mikrocystine/Microcystine/gi
Fatal dog poisoning after uptake of neurotoxic cyanobacteria associated with aquatic macrophytes in Tegeler See (Berlin, Germany) raised concerns about critical exposure of humans, especially children, to cyanotoxins produced by macrophyte associated cyanobacteria during recreational activity. From 2017 to 2021 a total of 398 samples of macrophytes washed ashore at bathing sites located at 19 Berlin lakes were analysed for anatoxins, microcystins, and cylindrospermopsins, as were 463 water samples taken in direct proximity to macrophyte accumulations. Cyanotoxins were detected in 66 % of macrophyte samples and 50 % of water samples, with anatoxins being the most frequently detected toxin group in macrophyte samples (58 %) and cylindrospermopsins in water samples (41 %). Microcoleus sp. associated with the water moss Fontinalis antipyretica was identified as anatoxin producing cyanobacterium in isolated strains as well as in field samples from Tegeler See. Anatoxin contents in macrophyte samples rarely exceeded 1 (micro)g/g macrophyte fresh weight and peaked at 9. 2 (micro)g/g f.w. Based on established toxicological points of departure, a critical anatoxin content of macrophyte samples of 3 (micro)g/g f.w. is proposed. Five samples, all taken in Tegeler See and all associated with the water moss Fontinalis antipyretica, exceeded this value. Contents and concentrations of microcystins and cylindrospermopsins did not reach critical levels. The potential exposure risks to anatoxins for children and dogs are assessed and recommendations are given. © 2022 The Authors
Cyanobacteria are favored by climate change and global warming; however, to date, mostresearch and monitoring programs have focused on planktic cyanobacteria. Benthic cyanobacte-ria blooms also increase and pose a risk to animal and human health; however, there is limitedknowledge of their occurrence, distribution and the toxins involved, especially in relation to theirplanktic conspeciï Ącs. Therefore, we analyzed the benthic and planktic life forms of cyanobacterialcommunities in 34 lakes in Germany, including a monitoring of cyanotoxins. Community analyseswere based on microscopic examination and Illumina sequencing of the 16S rRNA gene. The analysesof cyanotoxins were carried out using LC-MS/MS and ELISA. Observed benthic mats containingcyanobacteria consisted mainly of Nostocales and Oscillatoriales, being present in 35% of the lakes. Ana-toxin was the most abundant cyanotoxin in the benthic samples, reaching maximum concentrationsof 45,000Ìg/L, whereas microcystin was the predominate cyanotoxin in the open-water samples,reaching concentrations of up to 18,000Ìg/L. Based on the results, speciï Ąc lakes at risk of toxiccyanobacteria could be identiï Ąed. Our ï Ąndings suggest that monitoring of benthic cyanobacteria andtheir toxins should receive greater attention, ideally complementing existing open-water samplingprograms with little additional effort. © 2023 by the authors.
Chytrid parasites are increasingly recognized as ubiquitous and potent control agents of phytoplankton, including bloom-forming toxigenic cyanobacteria. In order to explore the fate of the cyanobacterial toxin microcystins (MCs) and assess potential upregulation of their production under parasite attack, a laboratory experiment was conducted to evaluate short- and long-term variation in extracellular and intracellular MC in the cyanobacteria Planktothrix agardhii and P. rubescens, both under chytrid infection and in the presence of lysates of previously infected cyanobacteria. MCs release under parasite infection was limited and not different to uninfected cyanobacteria, with extracellular toxin shares never exceeding 10%, substantially below those caused by mechanical lysis induced by a cold-shock. Intracellular MC contents in P. rubescens under infection were not significantly different from uninfected controls, whereas infected P. agardhii showed a 1.5-fold increase in intracellular MC concentrations, but this was detected within the first 48 hours after parasite inoculation and not later, indicating no substantial MC upregulation in cells being infected. The presence of lysates of previously infected cyanobacteria did not elicit higher intracellular MC contents in exposed cyanobacteria, speaking against a putative upregulation of toxin production induced via quorum sensing in response to parasite attack. These results indicate that chytrid epidemics can constitute a bloom decay mechanism that is not accompanied by massive release of toxins into the medium. © 2022 Elsevier
Das Projekt "Managing water resources for urban catchments" wird/wurde gefördert durch: Bundesministerium für Bildung und Forschung. Es wird/wurde ausgeführt durch: Technische Universität Dresden, Institut für Grundwasserwirtschaft, Juniorprofessur für Schadstoffhydrologie.
Cyanobacteria are known to produce a wide array of metabolites, including various classes of toxins. Among these, hepatotoxins (Microcystins), neurotoxins (Anatoxin-A and PSP toxins) or cytotoxins (Cylindrospermopsins) have been subjected to numerous, individual studies during the past twenty years. Reports of toxins co-occurrences, however, remain scarce in the literature. The present work is an inventory of cyanobacteria with a particular focus on Nostocales and their associated toxin classes from 2007 to 2010 in ten lakes used for drinking water production in France. The results show that potential multiple toxin producing species are commonly encountered in cyanobacteria populations. Individual toxin classes were detected in 75% of all samples. Toxin co-occurrences appeared in 40% of samples as two- or three-toxin combinations (with 35% for the microcystinsâ€Ìanatoxin combination), whereas four-toxin class combinations only appeared in 1% of samples. Toxin co-occurrences could be partially correlated to species composition and water temperature. Peak concentrations however could never be observed simultaneously and followed distinct, asymmetrical distribution patterns. As observations are the key for preventive management and risk assessment, these results indicate that water monitoring should search for all four toxin classes simultaneously instead of focusing on the most frequent toxins, i.e., microcystins Quelle: https://www.mdpi.com
Das Projekt "Depletion of algal toxin-contaminated water using selective biofilters based on plant-produced antibodies (plantibodies)" wird/wurde gefördert durch: Deutsche Forschungsgemeinschaft. Es wird/wurde ausgeführt durch: Technische Universität München, Institut für Wasserchemie und Chemische Balneologie, Lehrstuhl für Analytische Chemie und Wasserchemie.Although the use of genetically modified plants for bioremediation, or the in situ cleaning of contaminated sites, has been known for quite some time, little attention has so far been paid to the production of antibodies in plants and their ex vivo application in selective depletion. Therefore, highly affine and specific antibodies against algal toxins using microcystin as an example will be produced in plants at low cost within this research project. The basis is a monoclonal antibody (Mab 10E7, species: mouse) generated in a former research project. The sequence of the variable domains will be determined, optimized for plants and sub cloned into suitable plant transformation vectors, which already contain constant antibody sequences. In addition, a scFv fragment containing different tag sequences and fusion proteins will be constructed. Leaf-based (tobacco) as well as seed-based (barley) systems will be used.Affinity-purified plant-produced antibodies (plantibodies) will be characterized in detail for their binding properties using microtitre plate-ELISA and surface plasmon resonance (SPR). The monoclonal mouse antibody will be used as reference. To assure cost-efficiency for future applications, roughly purified fractions (sequential pH and temperature treatment followed by filtration) will be tested for the upscaling. Following immobilization of the plantibody fractions on suitable substrates, for instance membranes, porous polymer monoliths or in porous glasses, their application for depletion will be defined using model water samples spiked fortified with microcystins.
Insight into how environmental change determines the production and distribution of cyanobacterial toxins is necessary for risk assessment. Management guidelines currently focus on hepatotoxins (microcystins). Increasing attention is given to other classes, such as neurotoxins (e.g., anatoxin-a) and cytotoxins (e.g., cylindrospermopsin) due to their potency. Most studies examine the relationship between individual toxin variants and environmental factors, such as nutrients, temperature and light. In summer 2015, we collected samples across Europe to investigate the effect of nutrient and temperature gradients on the variability of toxin production at a continental scale. Direct and indirect effects of temperature were the main drivers of the spatial distribution in the toxins produced by the cyanobacterial community, the toxin concentrations and toxin quota. Generalized linear models showed that a Toxin Diversity Index (TDI) increased with latitude, while it decreased with water stability. Increases in TDI were explained through a significant increase in toxin variants such as MC-YR, anatoxin and cylindrospermopsin, accompanied by a decreasing presence of MC-LR. While global warming continues, the direct and indirect effects of increased lake temperatures will drive changes in the distribution of cyanobacterial toxins in Europe, potentially promoting selection of a few highly toxic species or strains. Quelle: https://www.mdpi.com
Das Projekt "Molecular mechanisms of tolerance of Daphnia to microcystins" wird/wurde gefördert durch: Deutsche Forschungsgemeinschaft. Es wird/wurde ausgeführt durch: Universität zu Köln, Biowissenschaftliches Zentrum, Zoologisches Institut, Aquatische chemische Ökologie.Man-made eutrophication of lakes has caused increased frequencies of cyanobacterial blooms, which go along with a reduction in abundance of Daphnia, the major herbivore of the phytoplankton. This reduced abundance of Daphnia is a major cause for the fact that food web manipulations frequently cause only short term improvements of water quality. The most frequently reported toxins of cyanobacterial blooms are microcystins, which are hepatotoxic to mammals and increase mortality in Daphnia. Although it has frequently been shown that Daphnia coexisting with cyanobacteria show increased tolerance to toxic cyanobacteria, the genetic basis of this tolerance is entirely unknown. Here the genetic basis of tolerance to microcystins in Daphnia will be investigated. A microcystin-producing strain and a mutant of that strain, which is deficient in microcystins, will be fed to a microcystin-tolerant and a microcystin-sensitive clone of Daphnia magna. Transcriptome analysis based on RNASeq will be used to identify differentially expressed genes that either differ constitutively in expression among the two Daphnia clones or are differentially expressed upon ingestion of microcystins. Bioinformatic analysis of the data and metabolic mapping will be used to identify key enzymes and genes that mediate tolerance to microcystins. Expression of selected differentially expressed genes will be validated in an independent experiment using qPCR. Further evidences for a mediation of microcystin tolerance by selected differentially expressed genes will be gained by investigating how the concentration of dietary microcystins affect gene expression. This will be achieved by feeding liposomes that are loaded with microcystins to Daphnia. Understanding the molecular mechanisms is indispensable for the understanding of the evolution of microcystin tolerance in Daphnia and is of potentially pivotal importance for the management of lakes with toxic cyanobacterial blooms.
Das Projekt "FP4-ENV 2C, The application of integrated biosensors with antibody and macrocyclic receptor libraries in the measurement of algal cells and toxins in water" wird/wurde gefördert durch: Kommission der Europäischen Gemeinschaften Brüssel. Es wird/wurde ausgeführt durch: Technische Universität Berlin, Fachbereich 07 Umwelt und Gesellschaft, Institut für Ökologie und Biologie, Fachgebiet Ökotoxikologie.General Information: The objective of the proposed work is to develop biosensor systems for the reliable monitoring of algae toxins and cells. Diagnosis will also be carried out using newly developed immunotoxicity assay. The use of an integrated electronic sensing principle is a very flexible approach, allowing the sample to be probed in many ways. The proposed approach is to use simple, disposable electrochemical affinity sensors. Affinity sensors are based on a receptor molecule specifically recognizing and binding an analyte. This is a very sensitive method and for biosensors the receptor most commonly used is an antibody. Recently a number of chemically or biochemically derived artificial receptors have been developed and their use in the construction of sensors has led to a new class of bio mimetic sensors. The principle of producing immunosensors has been demonstrated for other applications and is considered to have a high chance of success. Two state-of-the-art approaches are proposed for the production of receptor molecules. This is clearly a difficult task, but one which we believe will be successful. The proposers have considerable experience in antibody production, and significant experience in combinatorial synthesis. Both approaches have been demonstrated for use with compounds which are not dissimilar to those considered for this project. These approaches have the added advantage that they can be adapted to airy group of compounds. The biosensor array will be combined with multivariate analysis software for use in analyzing real samples taken from a number of sites throughout Europe. The instruments will be compared with current laboratory based methods such as chromatography. Immunotoxicity assay method will also be developed. The toxic and non-toxic algae will be fed to bivalves. The hemocytes will be tested concerning their phagozytotic activity. By recording immunological resistance (phagocytosis) in terms of quality and quantity, it is possible to detect biotoxins and their effects on the aquatic organisms. Experiments with reference biotoxins will be done with microcystin and anatoxin. Measurement of phagocytic activity offers ample opportunities for detecting unknown biotoxins by their influence on mussel immunology and hence a sensor can be constructed from this assay. Prime Contractor: Cranfield University, Biotechnology Centre; Cranfield.
Das Projekt "Toxin Production in Cyanobacteria" wird/wurde gefördert durch: Kommission der Europäischen Gemeinschaften Brüssel. Es wird/wurde ausgeführt durch: Universität Berlin (Humboldt-Univ.), Institut für Biologie.In many lakes and rivers toxic cyanobacteria are found. This causes severe problems for recreation and drinking water production. The toxicity of cyanobacteria is found to be highly vanable. Toxic blooms can change from toxic to non-toxic and vise versa. It is not clear how far this is caused by a succession of toxic and non-toxic strains within one species or, by the changes in toxicity of one population. Morphological analyses and physiological knowledge cannot give a solution here. Little is known of the relation of this toxin with the food-web in fresh waters. Is this toxin produced to prevent grazing, what is the distribution of this toxin in the food-web. In the synthesis of Microcystin the toxin produced by the cyanobacterium Microcystis the enzyme microcystin-synthetase plays a crucial role. Recently two institutes of this network have sequenced the genes if this enzyme. With this information it becomes possible to produce probes and construct-strains which are extremely important tools for physiological and ecological research concerning toxin production in continuous cultures and in natural systems. In this multidisciplinary research programme molecular biological tools will be developed and used to unravel the conditions under which this toxin is produced and what its influence is on the food-web of the natural systems. A network-programme has been developed to train young post-docs to incorporate molecular biological, physiological and ecological theories and techniques to study one problem: toxin production in cyanobacteria. - The programme contains training on the job, short training couses, working visits, and an 8 week workshop. Important topics are: - The production of DNA-probes and reporter strains to be used in physiology and ecology to recognize toxin production in laboratory and field populations. - Toxin production will carefully compared with ecological relevant conditions in laboratory and field systems. - In an eight-week field traing-course the whole team of the network is training to use all information and molecular tools to study the toxicity of a field population of Microcystis and to compare this with the results of the physiological and enclosure studies. Prime Contractor: Universiteit van Amsterdam, Research Institute voor Stoffen in Ecosystemen, Amsterdam NL.
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