In April and May 2011, three dogs died and one dog became ill after swimming in Lake IJmeer (The Netherlands). At the time, the lake was infested with the benthic cyanobacterial species Phormidium. A Eurasian Coot (Fulica atra) and a Black-headed Gull (Chroicocephalus ridibundus) also died near Lake IJmeer in the same period. One of the dogs and both birds were subjected to a pathological investigation. Furthermore, the Phormidium mat; algal samples from the dikes; contents of the animals' digestive systems and organ tissues were analysed for the following cyanobacterial toxins: (homo)anatoxin-a; (7-deoxy-)cylindrospermopsin; saxitoxins and gonyautoxins by LC-MS/MS. Samples were also analysed for the nontoxic (homo)anatoxin-a metabolites dihydro(homo)anatoxin-a and epoxy(homo)anatoxin-a. The dog necropsy results indicated neurotoxicosis and its stomach contained Phormidium filaments. Anatoxin-a was detected in the Phormidium mat (272 μg g⁻¹) dry weight, stdev 65, n=3) and in the dog's stomach contents (9.5 μg g⁻¹ dry weight, stdev 2.4, n=3). Both samples also contained the anatoxin-a metabolite dihydroanatoxin-a, and a trace of homoanatoxin-a was detected in the Phormidium mat. The birds were in bad nutritive condition at the time of necropsy and their stomachs and intestines did not contain any cyanobacterial material. Furthermore, no cyanobacterial toxins were detected in their stomachs, intestines and organs and they both had lesions that are not associated with cyanobacterial intoxication. This is the first report of anatoxin-a and homoanatoxin-a occurrence in The Netherlands, these toxins have likely caused the deaths of three dogs. The birds probably died of other causes. Dutch recreational waters are at this moment only screened for pelagic cyanobacterial species, the current bathing water protocol therefore does not protect humans and animals from negative effects of blooms of benthic cyanobacteria.
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http://dx.doi.org/10.1016/j.toxicon.2012.04.335 | DOI Listing |
Toxins (Basel)
February 2024
Department of Biological Sciences, Institute of Environment, Biscayne Bay Campus, Florida International University, 3000 NE 151st St., North Miami, FL 33181, USA.
Cyanobacterial harmful algal proliferations (cyanoHAPs) are increasingly associated with dog and livestock deaths when benthic mats break free of their substrate and float to the surface. Fatalities have been linked to neurotoxicosis from anatoxins, potent alkaloids produced by certain genera of filamentous cyanobacteria. After numerous reports of dog illnesses and deaths at a popular recreation site on Lady Bird Lake, Austin, Texas in late summer 2019, water and floating mat samples were collected from several sites along the reservoir.
View Article and Find Full Text PDFEnviron Microbiol
December 2023
Department of Biology, University of New Brunswick, Fredericton, New Brunswick, Canada.
Cyanophages are crucial for regulating cyanobacterial populations, but their influence on anatoxin-producing Microcoleus mat dynamics remains unexplored. Here, we use metagenomics to explore phage presence in benthic mats from the Wolastoq|Saint John River (New Brunswick, Canada) and the Eel River (California, USA). We recovered multiple viral-like sequences associated with different putative bacterial hosts, including two cyanophage genomes with apparently different replication strategies.
View Article and Find Full Text PDFEnviron Microbiol
November 2023
Department of Earth and Environmental Sciences, Cooperative Institute for Great Lakes Research, University of Michigan, Ann Arbor, Michigan, USA.
Seasonal changes in light and physicochemical conditions have strong impacts on cyanobacteria, but how they affect community structure, metabolism, and biogeochemistry of cyanobacterial mats remains unclear. Light may be particularly influential for cyanobacterial mats exposed to sulphide by altering the balance of oxygenic photosynthesis and sulphide-driven anoxygenic photosynthesis. We studied temporal shifts in irradiance, water chemistry, and community structure and function of microbial mats in the Middle Island Sinkhole (MIS), where anoxic and sulphate-rich groundwater provides habitat for cyanobacteria that conduct both oxygenic and anoxygenic photosynthesis.
View Article and Find Full Text PDFEnviron Sci Technol
October 2022
Biotoxin Metrology, National Research Council Canada, 1411 Oxford Street, Halifax, Nova Scotia B3H 3Z1, Canada.
Toxic benthic cyanobacterial mats are increasingly reported worldwide as being responsible for animal mortalities due to their production of the potent neurotoxin anatoxin-a (ATX) and its analogues. Improved analytical methods for anatoxins are needed to address public health and watershed management challenges arising from extremely high spatial and temporal variability within impacted systems. We present the development, validation, and application of a direct analysis in real-time-high-resolution tandem mass spectrometry (DART-HRMS/MS) method for analysis of anatoxins in cyanobacterial field samples, including a simplified sample preparation approach.
View Article and Find Full Text PDFmSystems
December 2021
Department of Earth and Environmental Sciences, University of Michigan, Ann Arbor, Michigan, USA.
Cyanobacterial mats profoundly influenced Earth's biological and geochemical evolution and still play important ecological roles in the modern world. However, the biogeochemical functioning of cyanobacterial mats under persistent low-O conditions, which dominated their evolutionary history, is not well understood. To investigate how different metabolic and biogeochemical functions are partitioned among community members, we conducted metagenomics and metatranscriptomics on cyanobacterial mats in the low-O, sulfidic Middle Island sinkhole (MIS) in Lake Huron.
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