Microcystins, BMAA and BMAA isomers in 100-year-old Antarctic cyanobacterial mats collected during Captain R.F. Scott’s Discovery Expedition

From the abstract of a new paper by Jungblut et. al (2018) published in European Journal of Phycology :

Microcystins (MCN), β-N-methylamino-L-alanine (BMAA) and anatoxin-a were investigated in Antarctic cyanobacterial mats collected from Ross Island and the McMurdo Ice Shelf, East Antarctica during Captain Scott’s ‘Discovery’ National Antarctic Expedition (1901–1904). Ultra-performance liquid chromatography-photodiode array detection (UPLC-PDA) and tandem mass spectrometry (MS/MS) analysis were used to quantify the cyanotoxins in seven cyanobacterial mat samples. MCNs were identified in six of the mat samples at concentrations from 0.5 to 16.1 µg g–1 dry weight. BMAA was found in one sample (528 ng g–1 dry weight, total BMAA), as well as two BMAA isomers, 2,4-diaminobutyric acid (DAB) and N-(2-aminoethyl) glycine (AEG) in six samples up to 6.56 and 6.79 μg g–1 dry weight, respectively. No anatoxin-a was detected. The findings confirm that MCNs, BMAA and BMAA isomers are preserved under dry herbarium conditions. The ‘Discovery’ cyanobacterial mat samples represent the oldest polar cyanobacterial samples found to contain cyanotoxins to date and provide new baseline data for cyanotoxins in Antarctic freshwater cyanobacterial mats from prior to human activity in Antarctica, the development of the ozone hole and current levels of climatic change.

Read the story by Katie Pavid in the Natural History Museum, UK website.

Reference:

A.D. Jungblut, J. Wilbraham, S.A. Banack, J.S. Metcalf & G.A. Codd (2018) Microcystins, BMAA and BMAA isomers in 100-year-old Antarctic cyanobacterial mats collected during Captain R.F. Scott’s Discovery Expedition, European Journal of Phycology, DOI: 10.1080/09670262.2018.1442587

Sponges-Cyanobacteria associations: Global diversity overview and new data from the Eastern Mediterranean

A new paper has been published by Konstantinou et al. (2018) from Cyanolab AUTH, in PlosOne. The authors summarize the global diversity of sponge species hosting cyanobacteria, as well as the diversity of cyanobacterial symbionts and provide a detailed list, along with new data from the Aegean Sea, a previously unexplored eastern ecoregion. The evaluation of the literature along with the new data from the Aegean Sea raised the number of sponge species known for hosting cyanobacteria to 320 and showed that the cyanobacterial diversity reported from sponges is yet underestimated. Highlight of the research is the isolation of nine cyanobacteria strains (only 19 cyanobacteria strains have been isolated to date from sponges). The nine isolated cyanobacteria were found to form novel clades within Synechococcus, Leptolyngbyaceae, Pseudanabaenaceae, and Schizotrichaceae. This is the first report of a Schizotrichaceae cyanobacterium associated with sponges. The results of this research propose the occurrence of new sponge-cyanobacteria associations and new cyanobacteria taxa.

Reference:

Konstantinou D, Gerovasileiou V, Voultsiadou E, Gkelis S (2018) Sponges- Cyanobacteria associations: Global diversity overview and new data from the Eastern Mediterranean. PLoS ONE 13(3): e0195001. https://doi.org/10.1371/journal.pone.0195001

Hot and toxic: Temperature regulates microcystin release from cyanobacteria

Highlights from a paper by Walls et al. (2017) in Science of the Total Environment:

– Toxin release from harmful cyanobacteria increases with warming.

– In-situ and laboratory studies showed elevated microcystin release between 20 and 25 °C.

– Elevated toxin release was coupled with a decline in cyanobacteria biomass.

– Water temperature could be used to forecast harmful algal bloom severity.

Reference:

Jeremy T. Walls, Kevin H. Wyatt, Jason C. Doll, Eric M. Rubenstein, Allison R. Rober (2017).
“Hot and toxic: Temperature regulates microcystin release from cyanobacteria”, Science of The Total Environment 610–611, pp. 786-795. https://doi.org/10.1016/j.scitotenv.2017.08.149.

 

 

Repeated five-day administration of L-BMAA, microcystin-LR, or as mixture, in adult C57BL/6 mice – lack of adverse cognitive effects

Abstract from the Myhre et al. (2018) paper in Scientific Reports:

“The cyanobacterial toxins β-methylamino-L-alanine (L-BMAA) and microcystin-LR (MC-LR; a potent liver toxin) are suspected to cause neurological disorders. Adult male C57BL/6JOlaHsd mice aged approximately 11 months were subcutaneously injected for five consecutive days with L-BMAA and microcystin-LR alone, or as a mixture. A dose-range study determined a tolerable daily dose to be ~31 µg MC-LR/kg BW/day based on survival, serum liver status enzymes, and relative liver and kidney weight. Mice tolerating the first one-two doses also tolerated the subsequent three-four doses indicating adaptation. The LD50 was 43–50 μg MC-LR/kg BW. Long-term effects (up to 10 weeks) on spatial learning and memory performance was investigated using a Barnes maze, were mice were given 30 µg MC-LR/kg BW and/or 30 mg L-BMAA/kg BW either alone or in mixture for five consecutive days. Anxiety, general locomotor activity, willingness to explore, hippocampal and peri-postrhinal cortex dependent memory was investigated after eight weeks using Open field combined with Novel location/Novel object recognition tests. Toxin exposed animals did not perform worse than controls, and MC-LR exposed animals performed somewhat better during the first Barnes maze re-test session. MC-LR exposed mice rapidly lost up to ~5% body weight, but regained weight from day eight.”

Reference:

Oddvar Myhre, Dag Marcus Eide, Synne Kleiven, Hans Christian Utkilen & Tim Hofer (2018), Scientific Reports 8, Article number: 2308. doi:10.1038/s41598-018-20327-y

 

Aerosol Emissions from Great Lakes Harmful Algal Blooms

Abstract from a recent paper by May et al. in ES&T:

In freshwater lakes, harmful algal blooms (HABs) of Cyanobacteria (blue-green algae) produce toxins that impact human health. However, little is known about the lake spray aerosol (LSA) produced from wave-breaking in freshwater HABs. In this study, LSA were produced in the laboratory from freshwater samples collected from Lake Michigan and Lake Erie during HAB and nonbloom conditions. The incorporation of biological material within the individual HAB-influenced LSA particles was examined by single-particle mass spectrometry, scanning electron microscopy with energy-dispersive X-ray spectroscopy, and fluorescence microscopy. Freshwater with higher blue-green algae content produced higher number fractions of individual LSA particles that contained biological material, showing that organic molecules of biological origin are incorporated in LSA from HABs. The number fraction of individual LSA particles containing biological material also increased with particle diameter (greater than 0.5 μm), a size dependence that is consistent with previous studies of sea spray aerosol impacted by phytoplankton blooms. Similar to sea spray aerosol, organic carbon markers were most frequently observed in individual LSA particles less than 0.5 μm in diameter. Understanding the transfer of biological material from freshwater to the atmosphere via LSA is crucial for determining health and climate effects of HABs.

Reference:

Nathaniel W. May, Nicole E. Olson, Mark Panas, Jessica L. Axson, Peter S. Tirella, Rachel M. Kirpes, Rebecca L. Craig, Matthew J. Gunsch, Swarup China, Alexander Laskin, Andrew P. Ault, and Kerri A. Pratt Environmental Science & Technology 2018 52 (2), 397-405 DOI: 10.1021/acs.est.7b03609

Are Harmful Algal Blooms Becoming the Greatest Inland Water Quality Threat to Public Health and Aquatic Ecosystems?

From an ET&C Focus article by Brooks et al. (2016):

“In this Focus article, the authors ask a seemingly simple question: Are harmful algal blooms (HABs) becoming the greatest inland water quality threat to public health and aquatic ecosystems? When HAB events require restrictions on fisheries, recreation, and drinking water uses of inland water bodies significant economic consequences result. Unfortunately, the magnitude, frequency, and duration of HABs in inland waters are poorly understood across spatiotemporal scales and differentially engaged among states, tribes, and territories. Harmful algal bloom impacts are not as predictable as those from conventional chemical contaminants, for which water quality assessment and management programs were primarily developed, because interactions among multiple natural and anthropogenic factors determine the likelihood and severity to which a HAB will occur in a specific water body. These forcing factors can also affect toxin production. Beyond site-specific water quality degradation caused directly by HABs, the presence of HAB toxins can negatively influence routine surface water quality monitoring, assessment, and management practices. Harmful algal blooms present significant challenges for achieving water quality protection and restoration goals when these toxins confound interpretation of monitoring results and environmental quality standards implementation efforts for other chemicals and stressors. Whether HABs presently represent the greatest threat to inland water quality is debatable, though in inland waters of developed countries they typically cause more severe acute impacts to environmental quality than conventional chemical contamination events. The authors identify several timely research needs. Environmental toxicology, environmental chemistry, and risk-assessment expertise must interface with ecologists, engineers, and public health practitioners to engage the complexities of HAB assessment and management, to address the forcing factors for HAB formation, and to reduce the threats posed to inland surface water quality.”

Reference:

Brooks, B. W., Lazorchak, J. M., Howard, M. D.A., Johnson, M.-V. V., Morton, S. L., Perkins, D. A.K., Reavie, E. D., Scott, G. I., Smith, S. A. and Steevens, J. A. (2016), Are harmful algal blooms becoming the greatest inland water quality threat to public health and aquatic ecosystems?. Environ Toxicol Chem, 35: 6–13. doi:10.1002/etc.3220

 

Special Issue: Emerging Marine Biotoxins (Toxins, Sep. 2018)

A Special Issue on “Emerging Marine Biotoxins” is under development in Toxins (MDPI), by Guest Editors Prof. Dr. Ana Gago-Martínez (University of Vigo, Spain) and Dr. Arjen Gerssen (RIKILT Wageningen Research, The Netherlands)

“This Special Issue will cover all emerging toxins that might be considered as a threat to human health, and different aspects, including analytical methods for detection and quantification, rapid tests for screening, toxicology, mode of action, occurrence, epidemiology, are considered as the main areas of interest.”

Deadline for manuscript submissions: 30 September 2018.

Details about this Special Issue can be found in the Toxins website.

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Metabolic solutions to the biosynthesis of BMAA and 2,4-DAB in cyanobacteria

The pathways of BMAA (and the related 2,4-DAB) biosynthesis in cyanobacteria are not known. A recent review by Peter Nunn and Geoffrey Codd considers possible metabolic routes, by analogy with reactions used in other species, by which these amino acids might be biosynthesised by cyanobacteria, which are a widespread potential environmental source of these neurotoxins.

Reference: Nunn, P. B. and Codd, G. A. (2017). “Metabolic solutions to the biosynthesis of some diaminomonocarboxylic acids in nature: Formation in cyanobacteria of the neurotoxins 3-N-methyl-2,3-diaminopropanoic acid (BMAA) and 2,4-diaminobutanoic acid (2,4-DAB)”. Phytochemistry 144, 253-270.

https://doi.org/10.1016/j.phytochem.2017.09.015

Microcystin-LR included in the proposed revision of the Drinking Water Directive !

The European Commission has issued a proposal for a Directive on the Quality of Water Intended for Human Consumption. The proposal is a recast of Directive 98/83/EC, which was amended in 2003, 2009 and 2015.

Microcystin-LR is included in the proposal as a “Chemical Parameter”, with a parametric value of 1μg/L, along with other organic compounds that are added in the list (Bisphenol A, Haloacetic acids, Nonylphenol, PFAS). Performance criteria for determination of MC-LR are specified as 30% uncertainty at the parametric value, while methods should comply to the requirements of ISO 17025.

Inclusion of MC-LR in the proposed Directive is a result of increased occurrence of microcystins in European waters and beyond, as well as of increased awareness of the health risks and hazards associated with toxic cyanobacteria. CYANOCOST has significant contributions in this field, including two books on chemical analysis of cyanotoxins and molecular detection of toxigenic cyanobacteria and many joint parers on cyanotoxin research. Since 2012, CYANOCOST has also contributed in raising awareness of cyanotoxins in Europe; in this sense, the proposed Directive is rewarding of the vast amount of voluntarily work done within the Network and highlights the important societal impact of COST Actions.

The proposed Directive is under public consultation till 2 April 2018. You can download the related documents and submit your feedback here.