Person: Fastner, Jutta
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Veröffentlichung Temperature Effects Explain Continental Scale Distribution of Cyanobacterial Toxins(2018) Mantzouki, Evanthia; Fastner, Jutta; Lürling, MiquelInsight 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.comVeröffentlichung Microcystin production revisited: conjugate formation makes a major contribution(2013) Meissner, Sven; Fastner, Jutta; Dittmann, ElkeThe impact of environmental stimuli on the productionof the widespread cyanobacterial hepatotoxinmicrocystin (MC) is under debate. Whereas transcriptionalstudies of the biosynthetic genes suggest aclear influence of light conditions on toxin productionthe data for the metabolite itself are inconsistent andhighly strain-specific. Here, we have reassessed theMC content by using two immunological detectiontechniques that allow a parallel quantification of MCin the methanolic extracts and the residual pellet fractionthat contains high molecular weight proteins. Ourresults show a significant proportion of MC in theprotein bound fraction in strains of Microcystis andPlanktothrix and of the related toxin nodularin (NOD)in Nodularia. Moreover, we could show a very strongincrease of MC after high light illumination in theprotein fraction contributing to a significant overallincrease in MC production under these conditionsthat is not seen in extracts analysed by LC-MS andELISA. The fact that a considerable portion of MC isneglected with current analysis techniques was alsoconfirmed for selected field samples. Immunofluorescencestudies suggest strain-specific differences inthe amount of MC conjugate formation.Quelle: Environmental Microbiology (2013) 15(6), 1810-1820Veröffentlichung Combating cyanobacterial proliferation by avoiding or treating inflows with high P load ̶ experiences from eight case studies(2015) Abella, Sally E. B.; Chorus, Ingrid; Litt, Arni; Fastner, Jutta; Morabito, Giuseppe; Voeroes, Lajos; Pálffy, Károly; Straile, Dietmar; Kümmerlin, Reiner; Matthews, David; Phillips, M. GeoffIncreased external nutrient loads of anthropogenic origin, especially those of phosphorus (P), were one of the major causes of eutrophication during the first half of the twentieth century in Europe. They led to deterioration of lake ecosystems, particularly including noxious blooms of (potentially toxic) cyanobacteria. From the 1970-1980s, strategies to decrease the phosphorus loads from sewage were increasingly implemented, among them are the ban of phosphates in detergents, the expansion of sewer systems and improvement in wastewater treatment to remove nutrients. Case studies of eight lakes, whose response to point source reduction of phosphorus was observed over decades, show that a pronounced reduction of the phosphorus load from point sources can be achieved either by the diversion of inflows carrying high loads, by upgraded sewage treatment, or by phosphorus precipitation in the major tributary directly before its inflow into the water body. Outcomes demonstrate that in order to effectively control cyanobacterial blooms, the measures taken need to reduce in-lake concentrations of total phosphorus below 20-50 Ţg L-1, with this threshold varying somewhat between lakes depending in particular on hydromorphological and biological conditions. Whether and when load reduction succeeds in controlling cyanobacteria depends primarily on the load remaining after remediation and on the water residence time.
Quelle: http://link.springer.com/Veröffentlichung Northern Expansion of Cylindrospermopsis raciborskii (Nostocales, Cyanoprokaryota) Observed in Shallow Highly Eutrophic Lake Nero (Russia)(2015) Babanazarova, O.V.; Sidelev, S.I.; Fastner, JuttaVeröffentlichung CYANOCOST special issue on cyanobacterial blooms: synopsis̶a critical review of the management options for their prevention, control and mitigation(2016) Ibelings, Bastiaan W.; Bormans, Myriam; Fastner, Jutta; Visser, Petra M.Nuisance, toxic cyanobacterial blooms are a persistent and globally expanding problem. Prevention of blooms requires that external and internal sources of nutrients are managed to levels where development of cyanobacterial blooms is restricted. Control of blooms, in which their presence is reduced to a level where they no longer pose a risk through additional measures such as biomanipulation or artificial mixing, demands that three elements come together: (1) understanding of the key ecological traits of the dominant cyanobacteria taxa, (2) system analysis of the lake, in particular its morphometry, water and nutrient balance, (3) adequate design and execution of the management methods of choice. All three elements are important for choosing effective management interventions and predicting their outcome. Mitigation of blooms reduces the risks and harmful effects of blooms if they cannot be prevented or sufficiently controlled, methods such as harvesting of surface scums or application of cyanocides may be used in those cases where water quality improvement is urgent. Ultimately, managing cyanobacterial blooms is most effective in the context of developing a Water Safety Plan. This is a risk assessment and management approach developed by the World Health Organization and provides a platform for bringing together the stakeholders who have a say about activities in the catchment causing eutrophication. Together, they can develop and implement control measures in the chain from catchment to drinking-water offtake which effectively mitigate eutrophication and thus protect humans and the lake ecosystem services they rely on from effects of toxic cyanobacteria.
Quelle: http://link.springer.comVeröffentlichung Toxic cyanobacteria and cyanotoxins in European waters(2017) Meriluoto, Jussi; Blaha, Ludek; Bojadzija, Gorenka; Fastner, JuttaVeröffentlichung Fatal neurotoxicosis in dogs associated with tychoplanktic, anatoxin-a producing tychonema sp. in mesotrophic Lake Tegel, Berlin(2018) Beulker, Camilla; Chorus, Ingrid; Fastner, JuttaIn May 2017, at least 12 dogs showed signs of acute neurotoxicosis after swimming in or drinking from Lake Tegel, a mesotrophic lake in Berlin, Germany, and several of the affected dogs died shortly afterwards despite intensive veterinary treatment. Cyanobacterial blooms were not visible at the water surface or the shorelines. However, detached and floating water moss (Fontinalis antipyretica) with high amounts of Tychonema sp., a potential anatoxin-a (ATX) producing cyanobacterium, was found near the beaches where the dogs had been swimming and playing. Necropsies of two of the dogs revealed no specific lesions beside the anamnestic neurotoxicosis. ATX was detected in concentrations up to 8700 Ìg Lâ Ì1 in the stomach contents, while other (neuro)toxic substances were not found. In the aqueous fraction of Fontinalis/Tychonema clumps sampled after the casualties, ATX was found in concentrations up to 1870 Ìg Lâ Ì1. This is the first report of a dense population of Tychonema sp. in stands of Fontinalis resulting in high ATX contents. This case emphasizes the need for further investigation of potentially toxic, non-bloom forming cyanobacteria in less eutrophic water bodies and underlines the novel challenge of developing appropriate surveillance schemes for respective bathing sites. Quelle: https://www.mdpi.comVeröffentlichung Nitrogen Limitation Promotes Accumulation and Suppresses Release of Cylindrospermopsins in Cells of Aphanizomenon Sp.(2014) Preußel, Karina; Chorus, Ingrid; Fastner, JuttaAs the biosynthesis of cylindrospermopsin (CYN) is assumed to depend on nitrogen availability, this study investigated the impact of nitrogen availability on intra- and extracellular CYN and deoxy-CYN (D-CYN) contents in three Aphanizomenon strains from temperate waters. Nitrogen deficient (-N) cultures showed a prolonged growth phase and intracellular toxin accumulation by a factor of 2-6. In contrast, cultures with additional nitrate supply (+N) did not accumulate CYN within the cells. Instead, the maximum conceivable CYN release estimated for dead cells (identified by SYTOX® Green staining) was much lower than the concentrations of dissolved CYN actually observed, suggesting these cultures actively release CYN from intact cells. Furthermore, we found remarkably altered proportions of CYN to D-CYN: as batch cultures grew, the proportion of D-CYN increased by up to 40% in +N medium, whereas D-CYN remained constant or decreased slightly in -N medium. Since +N cultures showed similar toxin patterns as -P cultures with increased extracellular CYNs and higher proportion of D-CYN we conclude that nitrogen limitation may affect the way the cells economize resources, especially the yield from phosphorus pools, and that this has an impact on CYN production and release. For water management, these result imply that nutrient availability not only determines the abundance of potentially CYN-producing cyanobacteria, but also the amount of extracellular CYNs (challenging drinking-water treatment) as well as the ratio of D-CYN to CYN (affecting toxicity).
Quelle: http://www.mdpi.com/Veröffentlichung Multi-toxin occurrences in ten french water resource reservoirs(2018) Pitois, Frederic; Fastner, Jutta; Pagotto, ChristelleCyanobacteria 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.comVeröffentlichung Cyanobacterial blooms. Ecology, prevention, mitigation and control: Editorial to a CYANOCOST Special Issue(2016) Ibelings, Bastiaan W.; Fastner, Jutta; Bormans, Myriam; Visser, Petra M.This is the Editorial to a Special Issue entitled "Cyanobacterial blooms. Ecology, prevention, mitigation and controlŁ. The Special Issue is a product of a European COST Action, CYANOCOST. In this Special Issue, contributions describe methods currently available for the management of cyanobacterial blooms, a key issue threatening the ecological functioning of lakes and the ecosystem services they provide . Contributions start with a section on the prevention of blooms, through the restriction of nutrient availability for cyanobacterial development at three levels: (1) in the catchment, (2) at the inflow to the lake and (3) in-lake methods, including nutrient release from the sediment. Then follows a section on control of blooms where blooms could be formed in the lake, but the chosen treatment restricts cyanobacterial growth to a level where risks and negative effects are minimal, e.g., artificial mixing, flushing or biomanipulation. The Special Issue continues with contributions on mitigation where blooms do develop, but physical and chemical methods mitigate the negative effects. For effective control key traits of the dominant cyanobacteria, characteristics of the lake system and an adequate design of the control method must come together. Each contribution answers questions like: what is the proposed or proven working mechanism of a given method? What have been the successes and failures? What are the reasons for success or failure? How is success linked to characteristics of the waterbody being treated? The Special Issue is concluded with contributions aiming at social and political aspects of bloom management .
Quelle: http://link.springer.com