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Ralf Steuer - One of the best experts on this subject based on the ideXlab platform.
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flux balance analysis of Cyanobacterial metabolism the metabolic network of synechocystis sp pcc 6803
PLOS Computational Biology, 2013Co-Authors: Henning Knoop, Marianne Grundel, Yvonne Zilliges, Robert Lehmann, Sabrina Hoffmann, Wolfgang Lockau, Ralf SteuerAbstract:Cyanobacteria are versatile unicellular phototrophic microorganisms that are highly abundant in many environments. Owing to their capability to utilize solar energy and atmospheric carbon dioxide for growth, Cyanobacteria are increasingly recognized as a prolific resource for the synthesis of valuable chemicals and various biofuels. To fully harness the metabolic capabilities of Cyanobacteria necessitates an in-depth understanding of the metabolic interconversions taking place during phototrophic growth, as provided by genome-scale reconstructions of microbial organisms. Here we present an extended reconstruction and analysis of the metabolic network of the unicellular cyanobacterium Synechocystis sp. PCC 6803. Building upon several recent reconstructions of Cyanobacterial metabolism, unclear reaction steps are experimentally validated and the functional consequences of unknown or dissenting pathway topologies are discussed. The updated model integrates novel results with respect to the Cyanobacterial TCA cycle, an alleged glyoxylate shunt, and the role of photorespiration in cellular growth. Going beyond conventional flux-balance analysis, we extend the computational analysis to diurnal light/dark cycles of Cyanobacterial metabolism.
Geoffrey A Codd - One of the best experts on this subject based on the ideXlab platform.
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Performance assessment of a cylindrospermopsin ELISA with purified compounds and Cyanobacterial extracts
Environmental Forensics, 2017Co-Authors: James S Metcalf, Fiona M. Young, Geoffrey A CoddAbstract:ABSTRACTDetecting low amounts of Cyanobacterial toxins (cyanotoxins) in water and clinical materials is useful to protect human health and to understand cyanotoxin intoxication events. Commonly-occurring Cyanobacterial compounds and extracts of cyanotoxin-producing Cyanobacteria were tested by a cylindrospermopsin ELISA, in comparison with HPLC-PDA. Other than the cylindrospermopsin variants, none of the purified Cyanobacterial peptides tested showed cross-reactivity in the cylindrospermopsin ELISA up to 100 µg/L, with the exception of nodularin-R. The cylindrospermopsin concentration in cylindrospermopsin-producing Cyanobacteria showed good agreement between ELISA and HPLC-PDA. However, extracts of Microcystis, Planktothrix, Nodularia, and Chlorella showed ELISA positives with such non-cylindrospermopsin-producing organisms reporting concentrations greater than 1 µg/L. When cylindrospermopsins were present, the cylindrospermopsin ELISA yielded good quantification, but false positive results from non-cyli...
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Grazing livestock are exposed to terrestrial Cyanobacteria
Veterinary Research, 2015Co-Authors: Bruce C Mcgorum, James S Metcalf, R Scott Pirie, Laura Glendinning, Gerry Mclachlan, Sandra A Banack, Geoffrey A CoddAbstract:While toxins from aquatic Cyanobacteria are a well-recognised cause of disease in birds and animals, exposure of grazing livestock to terrestrial Cyanobacteria has not been described. This study identified terrestrial Cyanobacteria, predominantly Phormidium spp., in the biofilm of plants from most livestock fields investigated. Lower numbers of other Cyanobacteria, microalgae and fungi were present on many plants. Cyanobacterial 16S rDNA, predominantly from Phormidium spp., was detected in all samples tested, including 6 plant washings, 1 soil sample and ileal contents from 2 grazing horses. Further work was performed to test the hypothesis that ingestion of cyanotoxins contributes to the pathogenesis of some currently unexplained diseases of grazing horses, including equine grass sickness (EGS), equine motor neuron disease (EMND) and hepatopathy. Phormidium population density was significantly higher on EGS fields than on control fields. The Cyanobacterial neurotoxic amino acid 2,4-diaminobutyric acid (DAB) was detected in plant washings from EGS fields, but worst case scenario estimations suggested the dose would be insufficient to cause disease. Neither DAB nor the Cyanobacterial neurotoxins β-N-methylamino-L-alanine and N-(2-aminoethyl) glycine were detected in neural tissue from 6 EGS horses, 2 EMND horses and 7 control horses. Phormidium was present in low numbers on plants where horses had unexplained hepatopathy. This study did not yield evidence linking known cyanotoxins with disease in grazing horses. However, further study is warranted to identify and quantify toxins produced by Cyanobacteria on livestock fields, and determine whether, under appropriate conditions, known or unknown cyanotoxins contribute to currently unexplained diseases in grazing livestock.
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Grazing livestock are exposed to terrestrial Cyanobacteria
Veterinary Research, 2015Co-Authors: Bruce C Mcgorum, James S Metcalf, R Scott Pirie, Laura Glendinning, Gerry Mclachlan, Sandra A Banack, Paul A Cox, Geoffrey A CoddAbstract:xins from aquatic Cyanobacteria are a well-recognised cause of disease in birds and animals, exposure of grazing livestock to terrestrial Cyanobacteria has not been described. This study identified terrestrial Cyanobacteria, predominantly Phormidium spp., in the biofilm of plants from most livestock fields investigated. Lower numbers of other Cyanobacteria, microalgae and fungi were present on many plants. Cyanobacterial 16S rDNA, predominantly from Phormidium spp., was detected in all samples tested, including 6 plant washings, 1 soil sample and ileal contents from 2 grazing horses. Further work was performed to test the hypothesis that ingestion of cyanotoxins contributes to the pathogenesis of some currently unexplained diseases of grazing horses, including equine grass sickness (EGS), equine motor neuron disease (EMND) and hepatopathy. Phormidium population density was significantly higher on EGS fields than on control fields. The Cyanobacterial neurotoxic amino acid 2,4-diaminobutyric acid (DAB) was detected in plant washings from EGS fields, but worst case scenario estimations suggested the dose would be insufficient to cause disease. Neither DAB nor the Cyanobacterial neurotoxins β-N-methylamino-L-alanine and N-(2-aminoethyl) glycine were detected in neural tissue from 6 EGS horses, 2 EMND horses and 7 control horses. Phormidium was present in low numbers on plants where horses had unexplained hepatopathy. This study did not yield evidence linking known cyanotoxins with disease in grazing horses. However, further study is warranted to identify and quantify toxins produced by Cyanobacteria on livestock fields, and determine whether, under appropriate conditions, known or unknown cyanotoxins contribute to currently unexplained diseases in grazing livestock.
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Cyanobacterial blooms statistical models describing risk factors for national scale lake assessment and lake management
Science of The Total Environment, 2011Co-Authors: Laurence Carvalho, Geoffrey A Codd, Claire Miller, Marian E Scott, Sian P Davies, Andrew N TylerAbstract:Abstract Cyanobacterial toxins constitute one of the most high risk categories of waterborne toxic biological substances. For this reason there is a clear need to know which freshwater environments are most susceptible to the development of large populations of Cyanobacteria. Phytoplankton data from 134 UK lakes were used to develop a series of Generalised Additive Models and Generalised Additive Mixed Models to describe which kinds of lakes may be susceptible to Cyanobacterial blooms using widely available explanatory variables. Models were developed for log Cyanobacterial biovolume. Water colour and alkalinity are significant explanatory variables and retention time and TP borderline significant (R 2 -adj = 21.9%). Surprisingly, the models developed reveal that nutrient concentrations are not the primary explanatory variable; water colour and alkalinity were more important. However, given suitable environments (low colour, neutral-alkaline waters), Cyanobacteria do increase with both increasing retention time and increasing TP concentrations, supporting the observations that Cyanobacteria are one of the most visible symptoms of eutrophication, particularly in warm, dry summers. The models can contribute to the assessment of risks to public health, at a regional- to national level, helping target lake monitoring and management more cost-effectively at those lakes at the highest risk of breaching World Health Organisation guideline levels for Cyanobacteria in recreational waters. The models also inform restoration options available for reducing Cyanobacterial blooms, indicating that, in the highest risk lakes (alkaline, low colour lakes), risks can generally be lessened through management aimed at reducing nutrient loads and increasing flushing during summer.
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first observation of cylindrospermopsin in anabaena lapponica isolated from the boreal environment finland
Environmental Toxicology, 2006Co-Authors: Lisa Spoof, Katri A Berg, Liisa Lepisto, James S Metcalf, Kirsti Lahti, Jarkko Rapala, Geoffrey A Codd, Jussi MeriluotoAbstract:The Cyanobacterial cytotoxin cylindrospermopsin has been mostly associated with Cyanobacteria present in tropical and subtropical regions. Cylindrospermopsin has recently been found in Cyanobacterial samples in central and southern Europe but the possible presence of the toxin in northern Europe has been unknown. Fifty-eight field and laboratory culture samples of Finnish Cyanobacteria were analyzed by high-performance liquid chromatography combined with UV diode-array detection, multiple reactant monitoring in a triple-quadrupole mass spectrometer (MS), and accurate mass measurements using a time-of-flight MS instrument. Cylindrospermopsin was confirmed by all three techniques in a culture sample of Anabaena lapponica at a concentration of 242 μg cylindrospermopsin per g freeze-dried Cyanobacterial material. © 2006 Wiley Periodicals, Inc. Environ Toxicol 21: 552–560, 2006.
James S Metcalf - One of the best experts on this subject based on the ideXlab platform.
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Performance assessment of a cylindrospermopsin ELISA with purified compounds and Cyanobacterial extracts
Environmental Forensics, 2017Co-Authors: James S Metcalf, Fiona M. Young, Geoffrey A CoddAbstract:ABSTRACTDetecting low amounts of Cyanobacterial toxins (cyanotoxins) in water and clinical materials is useful to protect human health and to understand cyanotoxin intoxication events. Commonly-occurring Cyanobacterial compounds and extracts of cyanotoxin-producing Cyanobacteria were tested by a cylindrospermopsin ELISA, in comparison with HPLC-PDA. Other than the cylindrospermopsin variants, none of the purified Cyanobacterial peptides tested showed cross-reactivity in the cylindrospermopsin ELISA up to 100 µg/L, with the exception of nodularin-R. The cylindrospermopsin concentration in cylindrospermopsin-producing Cyanobacteria showed good agreement between ELISA and HPLC-PDA. However, extracts of Microcystis, Planktothrix, Nodularia, and Chlorella showed ELISA positives with such non-cylindrospermopsin-producing organisms reporting concentrations greater than 1 µg/L. When cylindrospermopsins were present, the cylindrospermopsin ELISA yielded good quantification, but false positive results from non-cyli...
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Grazing livestock are exposed to terrestrial Cyanobacteria
Veterinary Research, 2015Co-Authors: Bruce C Mcgorum, James S Metcalf, R Scott Pirie, Laura Glendinning, Gerry Mclachlan, Sandra A Banack, Geoffrey A CoddAbstract:While toxins from aquatic Cyanobacteria are a well-recognised cause of disease in birds and animals, exposure of grazing livestock to terrestrial Cyanobacteria has not been described. This study identified terrestrial Cyanobacteria, predominantly Phormidium spp., in the biofilm of plants from most livestock fields investigated. Lower numbers of other Cyanobacteria, microalgae and fungi were present on many plants. Cyanobacterial 16S rDNA, predominantly from Phormidium spp., was detected in all samples tested, including 6 plant washings, 1 soil sample and ileal contents from 2 grazing horses. Further work was performed to test the hypothesis that ingestion of cyanotoxins contributes to the pathogenesis of some currently unexplained diseases of grazing horses, including equine grass sickness (EGS), equine motor neuron disease (EMND) and hepatopathy. Phormidium population density was significantly higher on EGS fields than on control fields. The Cyanobacterial neurotoxic amino acid 2,4-diaminobutyric acid (DAB) was detected in plant washings from EGS fields, but worst case scenario estimations suggested the dose would be insufficient to cause disease. Neither DAB nor the Cyanobacterial neurotoxins β-N-methylamino-L-alanine and N-(2-aminoethyl) glycine were detected in neural tissue from 6 EGS horses, 2 EMND horses and 7 control horses. Phormidium was present in low numbers on plants where horses had unexplained hepatopathy. This study did not yield evidence linking known cyanotoxins with disease in grazing horses. However, further study is warranted to identify and quantify toxins produced by Cyanobacteria on livestock fields, and determine whether, under appropriate conditions, known or unknown cyanotoxins contribute to currently unexplained diseases in grazing livestock.
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Grazing livestock are exposed to terrestrial Cyanobacteria
Veterinary Research, 2015Co-Authors: Bruce C Mcgorum, James S Metcalf, R Scott Pirie, Laura Glendinning, Gerry Mclachlan, Sandra A Banack, Paul A Cox, Geoffrey A CoddAbstract:xins from aquatic Cyanobacteria are a well-recognised cause of disease in birds and animals, exposure of grazing livestock to terrestrial Cyanobacteria has not been described. This study identified terrestrial Cyanobacteria, predominantly Phormidium spp., in the biofilm of plants from most livestock fields investigated. Lower numbers of other Cyanobacteria, microalgae and fungi were present on many plants. Cyanobacterial 16S rDNA, predominantly from Phormidium spp., was detected in all samples tested, including 6 plant washings, 1 soil sample and ileal contents from 2 grazing horses. Further work was performed to test the hypothesis that ingestion of cyanotoxins contributes to the pathogenesis of some currently unexplained diseases of grazing horses, including equine grass sickness (EGS), equine motor neuron disease (EMND) and hepatopathy. Phormidium population density was significantly higher on EGS fields than on control fields. The Cyanobacterial neurotoxic amino acid 2,4-diaminobutyric acid (DAB) was detected in plant washings from EGS fields, but worst case scenario estimations suggested the dose would be insufficient to cause disease. Neither DAB nor the Cyanobacterial neurotoxins β-N-methylamino-L-alanine and N-(2-aminoethyl) glycine were detected in neural tissue from 6 EGS horses, 2 EMND horses and 7 control horses. Phormidium was present in low numbers on plants where horses had unexplained hepatopathy. This study did not yield evidence linking known cyanotoxins with disease in grazing horses. However, further study is warranted to identify and quantify toxins produced by Cyanobacteria on livestock fields, and determine whether, under appropriate conditions, known or unknown cyanotoxins contribute to currently unexplained diseases in grazing livestock.
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first observation of cylindrospermopsin in anabaena lapponica isolated from the boreal environment finland
Environmental Toxicology, 2006Co-Authors: Lisa Spoof, Katri A Berg, Liisa Lepisto, James S Metcalf, Kirsti Lahti, Jarkko Rapala, Geoffrey A Codd, Jussi MeriluotoAbstract:The Cyanobacterial cytotoxin cylindrospermopsin has been mostly associated with Cyanobacteria present in tropical and subtropical regions. Cylindrospermopsin has recently been found in Cyanobacterial samples in central and southern Europe but the possible presence of the toxin in northern Europe has been unknown. Fifty-eight field and laboratory culture samples of Finnish Cyanobacteria were analyzed by high-performance liquid chromatography combined with UV diode-array detection, multiple reactant monitoring in a triple-quadrupole mass spectrometer (MS), and accurate mass measurements using a time-of-flight MS instrument. Cylindrospermopsin was confirmed by all three techniques in a culture sample of Anabaena lapponica at a concentration of 242 μg cylindrospermopsin per g freeze-dried Cyanobacterial material. © 2006 Wiley Periodicals, Inc. Environ Toxicol 21: 552–560, 2006.
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Cyanobacterial toxins, exposure routes and human health
European Journal of Phycology, 1999Co-Authors: Geoffrey A Codd, Kenneth A Beattie, S. G. Bell, Kunimitsu Kaya, Clive J. Ward, James S MetcalfAbstract:The production of potent toxins by bloom-, scum- and mat-forming Cyanobacteria, in fresh-, brackish and marine waters, appears to be a global phenomenon. Cyanobacterial toxins can also be produced by Cyanobacteria from terrestrial sources. The range and number of known Cyanobacterial toxins are increasing apace as associated poisoning incidents are investigated, and increasingly powerful analytical methods are applied to complement toxicity-based studies on both natural samples and laboratory isolates of Cyanobacteria. Water quality management to reduce toxic Cyanobacterial mass developments, and schemes to mitigate the potential effects of Cyanobacterial toxins, require an understanding of the occurrence and properties of the toxins and of the exposure routes via which the toxins present risks to health. Here, we review advances in the recognition of Cyanobacterial toxins and their toxicity, and of the exposure routes with reference to human health, namely via skin contact, inhalation, haemodialysis and ...
Henning Knoop - One of the best experts on this subject based on the ideXlab platform.
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flux balance analysis of Cyanobacterial metabolism the metabolic network of synechocystis sp pcc 6803
PLOS Computational Biology, 2013Co-Authors: Henning Knoop, Marianne Grundel, Yvonne Zilliges, Robert Lehmann, Sabrina Hoffmann, Wolfgang Lockau, Ralf SteuerAbstract:Cyanobacteria are versatile unicellular phototrophic microorganisms that are highly abundant in many environments. Owing to their capability to utilize solar energy and atmospheric carbon dioxide for growth, Cyanobacteria are increasingly recognized as a prolific resource for the synthesis of valuable chemicals and various biofuels. To fully harness the metabolic capabilities of Cyanobacteria necessitates an in-depth understanding of the metabolic interconversions taking place during phototrophic growth, as provided by genome-scale reconstructions of microbial organisms. Here we present an extended reconstruction and analysis of the metabolic network of the unicellular cyanobacterium Synechocystis sp. PCC 6803. Building upon several recent reconstructions of Cyanobacterial metabolism, unclear reaction steps are experimentally validated and the functional consequences of unknown or dissenting pathway topologies are discussed. The updated model integrates novel results with respect to the Cyanobacterial TCA cycle, an alleged glyoxylate shunt, and the role of photorespiration in cellular growth. Going beyond conventional flux-balance analysis, we extend the computational analysis to diurnal light/dark cycles of Cyanobacterial metabolism.
Dominik Martin-creuzburg - One of the best experts on this subject based on the ideXlab platform.
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Absence of sterols constrains food quality of Cyanobacteria for an invasive freshwater bivalve
Oecologia, 2012Co-Authors: Timo Basen, Karl-otto Rothhaupt, Dominik Martin-creuzburgAbstract:The accumulation of Cyanobacterial biomass may severely affect the performance of aquatic consumers. Here, we investigated the role of sterols in determining the food quality of Cyanobacteria for the invasive clam Corbicula fluminea , which has become a common benthic invertebrate in many freshwater ecosystems throughout the world. In standardized growth experiments, juvenile clams were fed mixtures of different Cyanobacteria ( Anabaena variabilis , Aphanothece clathrata , Synechococcus elongatus ) or sterol-containing eukaryotic algae ( Cryptomonas sp., Nannochloropsis limnetica , Scenedesmus obliquus ) . In addition, the Cyanobacterial food was supplemented with different sterols. We provide evidence that somatic growth of C. fluminea on Cyanobacterial diets is constrained by the absence of sterols, as indicated by a growth-enhancing effect of sterol supplementation. Thus, our findings contribute to our understanding of the consequences of Cyanobacterial mass developments for benthic consumers and highlight the importance of considering sterols as potentially limiting nutrients in aquatic food webs.
