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Special Issue "Potentially Toxic Benthic Microorganisms in Freshwater and Marine Ecosystems"

A special issue of Toxins (ISSN 2072-6651). This special issue belongs to the section "Marine and Freshwater Toxins".

Deadline for manuscript submissions: 31 August 2019

Special Issue Editors

Guest Editor
Dr. Philipp Hess

Laboratoire Phycotoxines, Ifremer, Nantes, France
Website | E-Mail
Phone: + 33 2 40 37 42 57
Interests: marine algal, bacterial and cyanobacterial toxins, mass spectrometric analysis of and biological assays for toxins and related metabolites, ecophysiology of toxin production and biosynthesis, HABs and climate change, reference materials, monitoring and risk evaluation
Guest Editor
Dr. Jean-Francois Humbert

Institute of Ecology and Environmental Sciences of Paris (iEES Paris), Sorbonne University, Paris, France
Website | E-Mail
Interests: cyanobacteria; cyanotoxins; ecology; microbial interactions; comparative genomics; cyanobacteria and cyanotoxin monitoring; risk managment

Special Issue Information

Dear Colleagues,

Benthic, epilitic, and epiphytic habitats in aquatic ecosystems are a way of life shared by numerous potentially-toxic microalgae and cyanobacteria, both in freshwater and marine ecosystems. In these latter ones, potentially toxic benthic microalgae have been extensively studied. While recent papers have shown the interest to better understand their benthic ecology, in particular their positive and negative interactions with other species into the biofilms, many aspects remain to be clarified: comparative risk of benthic and planktonic phase, species identification and distribution, toxin identity, etc.

In freshwater ecosystems, benthic cyanobacteria have received much less attention than planktonic species. Still, in the recent years, massive developments of river biofilms dominated by toxic cyanobacteria have been reported in several countries (New Zealand, France, USA, etc.), suggesting that changes in local or global environmental conditions might promote the recent increase of these events. Proliferations of benthic cyanobacteria have led to death of several dozen dogs in all these countries due to the production of anatoxins.

Consequently, increased knowledge is needed by scientists, ecosystem managers and other stakeholders to better comprehend the ecology and toxicity of these benthic cyanobacteria and microalgae and to finally limit the sanitary risks associated with their proliferations.

The aim of the current Special Issue is to gather the most recent research on benthic cyanobacteria and microalgae proliferating in marine and freshwater ecosystems and on their toxins. All papers dealing with the taxonomy, genetic diversity, ecology and toxicity of biofilms dominated by potentially-toxic cyanobacteria and microalgae and on risk assessment and management associated with such assemblages will be considered in this Special Issue.

Dr. Philipp Hess
Dr. Jean-Francois Humbert
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All papers will be peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a double-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Toxins is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 1500 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • Benthic cyanobacteria and microalgae
  • marine and freshwater ecosystems
  • taxonomy
  • ecology
  • toxicity

Published Papers (3 papers)

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Research

Open AccessArticle Development and Application of a Quantitative PCR Assay to Assess Genotype Dynamics and Anatoxin Content in Microcoleus autumnalis-Dominated Mats
Toxins 2018, 10(11), 431; https://doi.org/10.3390/toxins10110431
Received: 8 October 2018 / Revised: 21 October 2018 / Accepted: 23 October 2018 / Published: 26 October 2018
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Abstract
Microcoleus is a filamentous cyanobacteria genus with a global distribution. Some species form thick, cohesive mats over large areas of the benthos in rivers and lakes. In New Zealand Microcoleus autumnalis is an anatoxin producer and benthic proliferations are occurring in an increasing
[...] Read more.
Microcoleus is a filamentous cyanobacteria genus with a global distribution. Some species form thick, cohesive mats over large areas of the benthos in rivers and lakes. In New Zealand Microcoleus autumnalis is an anatoxin producer and benthic proliferations are occurring in an increasing number of rivers nationwide. Anatoxin content in M. autumnalis-dominated mats varies spatially and temporally, making understanding and managing proliferations difficult. In this study a M. autumnalis-specific TaqMan probe quantitative PCR (qPCR) assay targeting the anaC gene was developed. The assay was assessed against 26 non-M. autumnalis species. The assay had a detection range over seven orders of magnitude, with a limit of detection of 5.14 × 10−8 ng μL−1. The anaC assay and a cyanobacterial specific 16S rRNA qPCR were then used to determine toxic genotype proportions in 122 environmental samples collected from 19 sites on 10 rivers in New Zealand. Anatoxin contents of the samples were determined using LC-MS/MS and anatoxin quota per toxic cell calculated. The percentage of toxic cells ranged from 0 to 30.3%, with significant (p < 0.05) differences among rivers. The anatoxin content in mats had a significant relationship with the percentage of toxic cells (R2 = 0.38, p < 0.001), indicating that changes in anatoxin content in M. autumnalis-dominated mats are primarily related to the dominance of toxic strains. When applied to more extensive samples sets the assay will enable new insights into how biotic and abiotic parameters influence genotype composition, and if applied to RNA assist in understanding anatoxin production. Full article
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Open AccessArticle Cyanotoxins and Cyanobacteria Cell Accumulations in Drinking Water Treatment Plants with a Low Risk of Bloom Formation at the Source
Toxins 2018, 10(11), 430; https://doi.org/10.3390/toxins10110430
Received: 1 October 2018 / Revised: 18 October 2018 / Accepted: 23 October 2018 / Published: 26 October 2018
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Abstract
Toxic cyanobacteria have been shown to accumulate in drinking water treatment plants that are susceptible to algal blooms. However, the risk for plants that do not experience algal blooms, but that receive a low influx of cells, is not well known. This study
[...] Read more.
Toxic cyanobacteria have been shown to accumulate in drinking water treatment plants that are susceptible to algal blooms. However, the risk for plants that do not experience algal blooms, but that receive a low influx of cells, is not well known. This study determined the extent of cell accumulation and presence of cyanotoxins across the treatment trains of four plants in the Great Lakes region. Samples were collected for microscopic enumeration and enzyme-linked immunosorbent assay (ELISA) measurements for microcystins, anatoxin-a, saxitoxin, cylindrospermopsin, and β-methylamino-L-alanine (BMAA). Low cell influxes (under 1000 cells/mL) resulted in significant cell accumulations (over 1 × 105 cells/mL) in clarifier sludge and filter backwash samples. Microcystins peaked at 7.2 µg/L in one clarifier sludge sample, exceeding the raw water concentration by a factor of 12. Anatoxin-a was detected in the finished drinking water of one plant at 0.6 µg/L. BMAA may have been detected in three finished water samples, though inconsistencies among the BMAA ELISAs call these results into question. In summary, the results show that plants receiving a low influx of cells can be at risk of toxic cyanobacterial accumulation, and therefore, the absence of a bloom at the source does not indicate the absence of risk. Full article
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Graphical abstract

Open AccessFeature PaperArticle Spatial and Temporal Variability in the Development and Potential Toxicity of Phormidium Biofilms in the Tarn River, France
Toxins 2018, 10(10), 418; https://doi.org/10.3390/toxins10100418
Received: 30 August 2018 / Revised: 24 September 2018 / Accepted: 9 October 2018 / Published: 17 October 2018
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Abstract
Proliferation of Phormidium biofilms in rivers is becoming a worldwide sanitation problem for humans and animals, due to the ability of these bacteria to produce anatoxins. To better understand the environmental conditions that favor the development of Phormidium biofilms and the production of
[...] Read more.
Proliferation of Phormidium biofilms in rivers is becoming a worldwide sanitation problem for humans and animals, due to the ability of these bacteria to produce anatoxins. To better understand the environmental conditions that favor the development of Phormidium biofilms and the production of anatoxins, we monitored the formation of these biofilms and their toxins for two years in the Tarn River, biofilms from which are known to have caused the deaths of multiple dogs. As previously observed in New Zealand, Phormidium biofilm development occurred in riffle areas. The coverage of these biofilms at the bottom of the river exhibited strong spatial and temporal variations, but was positively correlated with water temperature and depth. Anatoxin-a was detected in less than 50% of the biofilms. The concentrations of these toxins in the biofilms exhibited high spatiotemporal variability, with the highest concentrations being recorded at the end of the summer period at the upstream sampling sites. These findings suggest that the maturity of the biofilms, combined with the local environmental conditions, have an impact on the production of anatoxin, making risk assessment for these benthic proliferations challenging. Full article
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Graphical abstract

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