Cyanotoxins in Bloom – Special Issue, Toxins

Dear colleagues,

The open access journal Toxins (ISSN 2072-6651, IF 3.895) is pleased to announce that we have launched a new Special Issue entitled:

“Cyanotoxins in Bloom: Ever-Increasing Occurrence and Global Distribution of Freshwater Cyanotoxins from Planktic and Benthic Cyanobacteria”.

We are serving as Guest Editors for this issue.

We would like to cordially invite you to contribute an article to the Special Issue. For more information on the issue, please visit the Special Issue website at

https://www.mdpi.com/journal/toxins/special_issues/Cyanotoxins_Bloom .

Kind regards,

Guest Editors

Dr. Triantafyllos Kaloudis

Athens Water Supply and Sewerage Company – EYDAP SA, Organic Micropollutants Lab – Quality Control Department, Flias 11, 13674 Menidi, Greece

Dr. Anastasia Hiskia

National Center for Scientific Research “DEMOKRITOS”, Institute of Nanoscience and Nanotechnology, Partiarchi Grigoriou E & Neapoleos 27 str., 15341, Agia Paraskevi, Athens, Greece

Dr. Theodoros Triantis

National Center for Scientific Research “DEMOKRITOS”, Institute of Nanoscience and Nanotechnology, Partiarchi Grigoriou E & Neapoleos 27 str., 15341, Agia Paraskevi, Athens, Greece

New microginins from cyanobacteria of Greek lakes

The first report of microginins isolated from cyanobacteria of Greek lakes was published by Zervou et al. in Chemosphere. As many as 36 new structures of microginins were elucidated with MS/MS techniques. The work was supported by a CYANOCOST STSM grant of Sevasti Zervou (NCSR Demokritos) to Hanna Mazur-Marzec (University of Gdansk).

The paper acknowledges CYANOCOST.

Reference:

Sevasti – Kiriaki Zervou, Spyros Gkelis, Triantafyllos Kaloudis, Anastasia Hiskia, Hanna Mazur-Marzec (2020). New microginins from cyanobacteria of Greek freshwaters,
Chemosphere, Volume 248, 125961. https://doi.org/10.1016/j.chemosphere.2020.125961.

 

Peptide patterns of Nostoc-like strains from alkali grassland areas

A paper by Riba et al. in Algal Research reports the chemotyping of terrestrial Nostoc-like isolates from alkali grassland areas by non-targeted peptide analysis.

From the Abstract:

The Nostoc genus is a well-known heterocytous, filamentous cyanobacterium which can be found all over the world. The size of terrestrial and/or freshwater colonies can be microscopic and macroscopic as well. In addition, Nostoc species are one of the most common photosynthetic cyanobacterial partners in symbiotic interactions. Terrestrial cyanobacterial colonies were collected and isolated in this study from various alkali grassland habitats (Great Hungarian Plain). Altogether 133 colonies were isolated from the 65 collected samples. The peptide patterns of the Nostoc-like strains were examined using HPLC-ESI-MS/MS and 41 peptides were identified from 45 isolated Nostoc-like strains; these compounds belonged to 4 different peptide classes. Twelve nostoginin/microginin, 16 anabaenopeptin, 12 banyaside/suomilide variants were identified. 37% of our isolated Nostoc-like strains produced some of the peptide metabolites we tested. These strains showed distinct chemotypes according to their peptide patterns, and can be divided into 4 groups based on their metabolisms. Strains either contained: (1) nostoginins/microginins, (2) anabaenopeptins, (3) anabaenopeptins and banyasides or (4) banyasides as major compounds. Banyasides were present in many of our strains and showed very high intensity in some cases. A number of previously unknown banyaside variants have been identified.

The paper acknowledges CYANOCOST.

Reference:

Milán Riba, Attila Kiss-Szikszai, Sándor Gonda, Péter Parizsa, Balázs Deák, Péter Török, Orsolya Valkó, Tamás Felföldi, Gábor Vasas (2020). Chemotyping of terrestrial Nostoc-like isolates from alkali grassland areas by non-targeted peptide analysis. Algal Research 46, 101798. https://doi.org/10.1016/j.algal.2020.101798.

Effects of hydrogen peroxide on cyanobacteria and microcystins in irrigation water.

A new paper by Spoof et al. in Environmental Science and Pollution Research reports a series of experiments where lysis of cyanobacteria in abstracted lake water was induced by the use of hydrogen peroxide.

From the abstract:

This paper reports a series of experiments where lysis of cyanobacteria in abstracted lake water was induced by the use of hydrogen peroxide and the fate of released MCs was followed. The hydrogen peroxide–treated water was then used for spray irrigation of cultivated spinach and possible toxin accumulation in the plants was monitored. The water abstracted from Lake Köyliönjärvi, SW Finland, contained fairly low concentrations of intracellular MC prior to the hydrogen peroxide treatment (0.04 μgL −1 in July to 2.4 μgL −1 in September 2014). Hydrogen peroxide at sufficient doses was able to lyse cyanobacteria efficiently but released MCs were still present even after the application of the highest hydrogen peroxide dose of 20 mg L−1. No traces of MC were detected in the spinach leaves. The viability of moving phytoplankton and zooplankton was also monitored after the application of hydrogen peroxide. Hydrogen peroxide at 10 mg L−1 or higher had a detrimental effect on the moving phytoplankton and zooplankton.

The paper acknowledges CYANOCOST.

Reference:

Spoof, L., Jaakkola, S., Važić, T. Važić, T., Häggqvist, K., Kirkkala, T., Ventelä, A-M., Kirkkala, T., Svirčev, Z., Meriluoto, J. Elimination of cyanobacteria and microcystins in irrigation water—effects of hydrogen peroxide treatment. Environ Sci Pollut Res (2020). https://doi.org/10.1007/s11356-019-07476-x

New research sheds light on the underlying mechanisms of 2,4 DABA neurotoxic effects

A new paper by S. Spacic et al. in Aquatic Toxicology, presents important findings with regards to the mechanisms underlying 2,4-DABA neurotoxicity. From the abstract:

“Recent studies suggest that 2,4-DABA, a neurotoxic excitatory amino acid present in virtually all environments, but predominantly in aquatic ecosystems may be a risk factor for development of neurodegenerative diseases in animals and humans. Despite its neurotoxicity and potential environmental importance, mechanisms underlying the excitatory and putative excitotoxic action of 2,4-DABA in neurons are still unexplored. We previously reported on extensive two-stage membrane depolarization and functional disturbances in leech Retzius neurons induced by 2,4-DABA. Current study presents the first detailed look into the electrophysiological processes leading to this depolarization. Intracellular recordings were performed on Retzius neurons of the leech Haemopis sanguisuga using glass microelectrodes and input membrane resistance (IMR) was measured by injecting hyperpolarizing current pulses through these electrodes. Results show that the excitatory effect 2,4-DABA elicits on neurons’ membrane potential is dependent on sodium ions. Depolarizing effect of 5·10−3 mol/L 2,4-DABA in sodium-free solution was significantly diminished by 91% reducing it to 3.26 ± 0.62 mV and its two-stage nature was abrogated. In addition to being sodium-dependent, the depolarization of membrane potential induced by this amino acid is coupled with an increase of membrane permeability, as 2,4-DABA decreases IMR by 8.27 ± 1.47 MΩ (67.60%). Since present results highlight the role of sodium ions, we investigated the role of two putative sodium-dependent mechanisms in 2,4-DABA-induced excitatory effect – activation of ionotropic glutamate receptors and the electrogenic transporter for neutral amino acids. Excitatory effect of 5·10−3 mol/L 2,4-DABA was partially blocked by 10-5 mol/L 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX) a non-NMDA receptor antagonist as the first stage of membrane depolarization was significantly reduced by 2.59 ± 0.98 mV (40%), whilst second stage remained unaltered. Moreover, involvement of the sodium-dependent transport system for neutral amino acids was investigated by equimolar co-application of 5·10−3 mol/L 2,4-DABA and L-alanine, a competitive inhibitor of this transporter. Although L-alanine exhibited no effect on the first stage of membrane depolarization elicited by 2,4-DABA, it substantially reduced the second stage (the overall membrane depolarization) from 39.63 ± 2.22 mV to 16.28 ± 2.58 mV, by 58.92%. We therefore propose that the electrophysiological effect of 2,4-DABA on Retzius neurons is mediated by two distinct mechanisms, i.e. by activation of ionotropic glutamate receptor that initiates the first stage of membrane depolarization followed by the stimulation of an electrogenic sodium-dependent neutral amino acid transporter, leading to additional influx of positive charge into the cell and the second stage of depolarization.”

The paper acknowledges CYANOCOST.

Reference:

Svetolik Spasic, Marija Stanojevic, Jelena Nesovic Ostojic, Sanjin Kovacevic, Jasna Todorovic, Marko Dincic, Vladimir Nedeljkov, Milica Prostran, Srdjan Lopicic (2020).
Two distinct electrophysiological mechanisms underlie extensive depolarization elicited by 2,4 diaminobutyric acid in leech Retzius neurons. Aquatic Toxicology 220, 105398.
https://doi.org/10.1016/j.aquatox.2019.105398.

 

Frontiers topic: Global Intensification of Cyanobacterial Blooms: The Driving Forces and Mitigation Approaches

This Frontiers Research Topic presents research papers and reviews that explore novel approaches expanding our understanding of the development of toxic phytoplankton blooms and their immense performance in a changing environment, with particular focus on Microcystis sp. It aims to address various aspects of cyanobacterial blooms including the following:

• abiotic and biotic drivers of cyanobacteria blooms

• biological role of secondary metabolites, including cyanotoxins, in the bloom’s lifecycle,

• allelopathic and info-chemical interactions between microorganisms involved in toxic blooms,

• competition in host/parasite interactions, including cy-anophages,

• novel strategies for mitigation of cyanobacterial blooms.

Topic Editors:

Aaron Kaplan, Hebrew University of Jerusalem, Israel),
Rainer Kurmayer, University of Innsbruck, Austria,
Assaf Sukenik, Kinneret Limnological Laboratory, Israel Oceanographic and Limnological Research, Leon H. Charney School of Marine Sciences, University of Haifa, Migdal, Israel.

Deadline for submission of abstracts: 01 April 2020.

Link to the webpage of this Frontiers Topic

 

Special Issue “Selected Papers from the 11th International Conference on Toxic Cyanobacteria” – Toxins

Dear Colleagues,

The International Conference on Toxic Cyanobacteria is a periodic summit of an international community focusing on the study of cyanotoxins and toxic cyanobacteria. The next ICTC 11 will be held in Kraków, Poland, 5–10 May, 2019.

The Local Organizing Committee agreed with Toxins to call for a Special Issue related to the research presented during ICTC 11. The submitted articles should contain recent and most important findings discussed during the conference including: the occurrence of toxic/invasive cyanobacteria in the context of climate changes; ecology of cyanobacteria with special emphasis on abiotic and biotic factors which regulate their growth and/or toxin production; physiological function, environmental significance and biotechnological application of secondary cyanometabolites; physiology and molecular biology of cyanobacteria; toxicity and harmful effects; risk identification and water management.

Link to the special issue: https://www.mdpi.com/journal/toxins/special_issues/Conference_Toxic_Cyanobacteria

Additional links to the conference which you may find useful: http://ictc11.org/special-issues/

On behalf of the Local Organizing Committee

Dr. Dariusz Dziga
Guest Editor

Special Issue “Harmful Cyanobacteria and Their Metabolites” – Applied Sciences

Dear Colleagues,

The ongoing eutrophication of aquatic ecosystems has increased cyanobacterial blooms and also intensified the problems caused by the blooms. Harmful cyanobacteria and their toxic metabolites are known to cause health concerns in humans, animals, and plants, and water-users continue to experience cyanobacterial hazards and nuisance in Europe and other parts of the world as evidenced by some recent events.

The Special Issue “Harmful Cyanobacteria and Their Metabolites” in the journal Applied Sciences has a wide scope and it is intended to address some of the gaps in our knowledge concerning the management of cyanobacterial problems. It deals with, e.g., the occurrence of harmful cyanobacteria, methods for the analysis of noxious cyanometabolites, fate/impact/health effects of cyanotoxins, as well as management measures related to harmful cyanobacteria.

Some examples of work relevant for the Special Issue includes manuscripts on toxic invasive cyanobacteria; occurrence of toxic cyanobacteria in less-studied environments; cyanobacterial adaptations to climate change especially in relation to toxin production; cyanobacterial production of taste and odor compounds; management of harmful cyanobacteria in protected ecosystems; exposure assessment and effects of cyanotoxins in aquatic and terrestrial organisms including humans; novel methods for monitoring and analysis of cyanotoxins; prevention and control measures for the elimination of cyanobacterial problems. Review papers promoting international initiatives for the management of cyanobacterial problems may also be considered if presented with a strong scientific rationale but the potential authors of such papers are encouraged to contact the Guest Editors in advance.

Dr. Jussi Meriluoto
Dr. Nada Tokodi
Guest Editors

Link to the webpage of the Issue.

Download the flyer of the Issue.

First study to show that microginins are genotoxic

Abstract from a paper by Ujvarosi et al. (2019), published in Chemospere :

Microginins (MGs) are bioactive metabolites mainly produced by Microcystis spp., (Cyanobacteria) commonly found in eutrophic environments. In this study, the cytotoxic and genotoxic activities of four MG congeners (MG FR3, MG GH787, cyanostatin B, MGL 402) and a well characterized cyanobacterial extract B-14-01 containing these metabolites were evaluated in the human hepatocellular carcinoma (HepG2) cell line. The cytotoxicity was measured with the MTT assay, while genotoxicity was studied with the comet, γH2AX and cytokinesis block (CBMN) micronucleus assays. The viability of cells after 24 h was significantly affected only by the extract, whereas after 72 h a concentration dependent decrease in cell proliferation was observed for the extract and tested microginins, with MGL 402 being the most potent and MG FR3 the least potent congener. The extract and all tested congeners induced DNA strand breaks after 4 and 24 h exposure. The most potent was the extract, which induced concentration and time dependent increase in DNA damage at concentrations ≥0.01 μg mL−1. Among microginins the most potent was MGL 402 (increase in DNA strand breaks at ≥ 0.01 μg mL−1) and MG FR3 was the least potent (increase in DNA strand breaks at ≥ 1 μg mL−1). However, no induction of DNA double strand breaks was observed after 24 and 72-h exposure to the cyanobacterial extract or MGs. Induction of genomic instability was observed in cells exposed to MG GH787, cyanostatin B and the extract B-14-01. This study is the first to provide the evidence that microginins exert genotoxic activity.

The paper is a product of joined research by groups in Slovenia and Hungary and features CYANOCOST members Bojana Zegura, Gabor Vasas, Klara Hercog, Metka Filipic. The authors acknowledge CYANOCOST.

Reference:

Andrea Zsuzsanna Ujvárosi, Klara Hercog, Milán Riba, Sándor Gonda, Metka Filipič, Gábor Vasas, Bojana Žegura (2019). “The cyanobacterial oligopeptides microginins induce DNA damage in the human hepatocellular carcinoma (HepG2) cell line”, Chemosphere, Volume 240,  https://doi.org/10.1016/j.chemosphere.2019.124880.

 

New marine cyanobacteria species found by Cyanolab in Aegean sea

A new paper by Konstantinou et al. from Cyanolab AUTH (Head: Dr. Spyros Gkelis), published in Journal of Phycology. The authors propose a novel marine genus Leptothoe gen. nov. and describe three new sponge-associated species:  Le. sithoniana, Le. kymatousa, and Le.  spongobia, based on a combination of molecular, chemical and morphological approach. The new sponge-associated Leptothoe species show distinct characters compared to other marine Leptolyngbyaceae, reinforcing the investigation of cyanobacterial diversity associated with sponges. Interestingly, Leptothoe spongobia TAU-MAC 1115 isolated from the sponge Acanthella acuta was shown to produce microcystin-RR indicating that microcystin production among marine cyanobacteria could be more widespread than previously determined.

Reference:

Konstantinou, D., Voultsiadou, E., Panteris, E., Zervou, S. K., Hiskia, A., & Gkelis, S. (2019). Leptothoe, a new genus of marine cyanobacteria (Synechococcales) and three new species associated with sponges from the Aegean Sea. Journal of phycology.  https://doi.org/10.1111/jpy.12866