Toxic cyanobacteria in Svalbard: chemical diversity of microcystins detected using a liquid chromatography mass spectrometry precursor ion screening method

Cyanobacteria synthesize a large variety of secondary metabolites including toxins. Microcystins (MCs) with hepato- and neurotoxic potential are well studied in bloom-forming planktonic species of temperate and tropical regions. Cyanobacterial biofilms thriving in the polar regions have recently emerged as a rich source for cyanobacterial secondary metabolites including previously undescribed congeners of microcystin. However, detection and detailed identification of these compounds is difficult due to unusual sample matrices and structural congeners produced. We here report a time-efficient liquid chromatography-mass spectrometry (LC-MS) precursor ion screening method that facilitates microcystin detection and identification. We applied this method to detect six different MC congeners in 8 out of 26 microbial mat samples of the Svalbard Archipelago in the Arctic. The congeners, of which [Asp3, ADMAdda5, Dhb7] MC-LR was most abundant, were similar to those reported in other polar habitats. Microcystins were also determined using an Adda-specific enzyme-linked immunosorbent assay (Adda-ELISA). Nostoc sp. was identified as a putative toxin producer using molecular methods that targeted 16S rRNA genes and genes involved in microcystin production. The mcy genes detected showed highest similarities to other Arctic or Antarctic sequences. The LC-MS precursor ion screening method could be useful for microcystin detection in unusual matrices such as benthic biofilms or liche

Pole-to-Pole Connections : Similarities between Arctic and Antarctic Microbiomes and Their Vulnerability to Environmental Change

Acknowledgments JK acknowledges the Carl Zeiss foundation for PhD funding, the Marie-Curie COFUND-BEIPD PostDoc fellowship for PostDoc funding, FNRS travel funding and the logistical and financial support by UNIS. JK and FK acknowledge the Natural Environment Research Council (NERC) Antarctic Funding Initiative AFI-CGS-70 (collaborative gearing scheme) and logistic support from the British Antarctic Survey (BAS) for field work in Antarctica. JK and CZ acknowledge the Excellence Initiative at the University of Tübingen funded by the German Federal Ministry of Education and Research and the German Research Foundation (DFG). FH, AV, and PB received funding from MetaHIT (HEALTH-F4-2007-201052), Microbios (ERC-AdG-502 669830) and the European Molecular Biology Laboratory (EMBL). We thank members of the Bork group at EMBL for helpful discussions. We acknowledge the EMBL Genomics Core Facility for sequencing support and Y. P. Yuan and the EMBL Information Technology Core Facility for support with high-performance computing and EMBL for financial support. PC is supported by NERC core funding to the BAS “Biodiversity, Evolution and Adaptation” Team. MB was funded by Helge Ax:son Johnsons Stiftelse and PUT1317. DRD acknowledges the DFG funded project DI698/18-1 Dietrich and the Marie Curie International Research Staff Exchange Scheme Fellowship (PIRSES-GA-2011-295223). Operations in the Canadian High Arctic were supported by the Natural Sciences and Engineering Research Council of Canada (NSERC), ArcticNet and the Polar Continental Shelf Program (PCSP). We are also grateful to the TOTAL Foundation (Paris) and the UK NERC (WP 4.3 of Oceans 2025 core funding to FCK at the Scottish Association for Marine Science) for funding the expedition to Baffin Island and within this context Olivier Dargent and Dr. Pieter van West for sample collection, and the Spanish Ministry of Science and Technology through project LIMNOPOLAR (POL200606635 and CGL2005-06549-C02-01/ANT to AQ as well as CGL2005-06549-C02-02/ANT to AC, the last of these co-financed by European FEDER funds). We are grateful for funding from the MASTS pooling initiative (The Marine Alliance for Science and Technology for Scotland), funded by the Scottish Funding Council (HR09011) and contributing institutions. Supplementary Material The Supplementary Material for this article can be found online at: https://www.frontiersin.org/articles/10.3389/fevo.2017.00137/full#supplementary-materialPeer reviewedPublisher PD

Contribution of cyanobacteria to the building of travertines in a calcareous stream

The ambient temperature travertine deposits of the calcareous Hoyoux River (Modave, Belgium) and several tributaries are organized and promoted by the filamentous cyanobacterium identified by its morphotype and ecological properties as Phormidium cf. incrustatum. A combination of techniques was used to study this biotope: physico-chemical parameters and CO2 measurements, Scanning and Transmission Electron Microscopy, RAMAN microspectroscopy. A molecular diversity study with pyrosequencing of the cyanobacterial 16S rRNA is in progress. A potential candidate was isolated in culture.Caractérisation des processus de fossilisation dans les roches calcaires et évolution des cyanobactéries impliquées dans la biominéralisatio

Diversität und Ökophysiologie cyanobakterieller Mattengemeinschaften in den Ökosystemen der Arktis und Antarktis

Cyanobacteria (more commonly known as blue-green algae) are photosynthetic bacteria with a worldwide distribution. They are most common in the freshwater environment but are also present in many marine waters. As they are pioneer-organisms and they can often be found in extreme environments. They also constitute the dominant primary producers in the terrestrial Polar Regions and therefore have a pivotal role in polar ecosystems. In freshwater streams, ponds, and lakes that are formed during the polar summer, they occur as benthic or floating mats several millimetres to centimetres thick, sometimes covering several square meters. These mats are the nutritional basis and the micro-habitat for several other types of organisms (primarily proto- and metazoa).This study describes the species diversity of cyanobacterial mat communities from the Arctic and Antarctic that were collected prior to and during the thesis using molecular phylogenetic techniques. The characterization was accomplished by morphological identification as well as the sequencing of the ribosomal RNA genes and the more variable ITS-region (intergenic spacer region). Conventional molecular biological methods (clone-library, automated ribosomal intergenic spacer analysis (ARISA)) were applied as well as „Next-Generation-Sequencing“ based on the 454® technology. The latter allows thousands of sequences to be obtained from a single sample. Using these methods a comprehensive picture of the phylogenetic diversity could be obtained and mats from the Arctic and the Antarctic region compared with and within each other.Cyanobacteria synthesize multiple secondary metabolites, some of which are toxic to most higher organisms including humans. Health hazards or even life threatening incidents regularly occur in the temperate and tropical regions during bloom events (mass-occurrences of cyanobacteria).This study demonstrated that cyanobacterial toxins are present in cyanobacterial mats of the Arctic and the Antarctic. In the Arctic two cyanobacterial toxins were recorded for the first time: An unusual variant of the cyanobacterial hepatotoxin microcystin. This toxin acts as an inhibitor of cellular protein phosphatases (PP 1, 2A, 4 und 5). The second toxin identified was the neurotoxic saxitoxin which inhibits neuronal signal propagation by blocking Na2+ channels. Cylindrospermopsin, a protein synthesis inhibitor was detected for the first time in the Antarctic. These results indicate that the potential for toxin production in the cyanobacterial communities of the Arctic and Antarctic is higher than previously thought.The Polar Regions are currently subject to profound change: Temperatures are increasing at higher rates than anywhere else on the planet. In is expected that a consequence of climate change will be that the composition of the mat communities comprising cyanobacteria and associated proto- and metazoans, are affected. Because of their simple trophic structure and their sensitivity to change, they are an ideal model system for the exploration of climate induced changes. Therefore the effect of climate change on the diversity and toxicity of cyanobacterial mats was studied here in a laboratory based approach. Increased temperatures (8 - 16 °C) resulted in a higher concentration of microcystin as well as in structural changes of the community composition. Based on these results as well as on previous studies, it can be expected that climate change will affect the toxicity of cyanobacteria in the Polar Regions and in lower latitudes. A general increase and a wider distribution of toxic cyanobacteria, as well as an increase of the rate of toxin production may be expected

Diversity of toxin and non-toxin containing cyanobacterial mats of meltwater ponds on the Antarctic Peninsula: a pyrosequencing approach

Despite their pivotal role as primary producers, there is little information as to the diversity and physiology of cyanobacteria in the meltwater ecosystems of polar regions. Thirty cyanobacterial mats from Adelaide Island, Antarctica were investigated using 16S rRNA gene pyrosequencing and automated ribosomal intergenic spacer analysis, and screened for cyanobacterial toxins using molecular and chemical approaches. A total of 274 operational taxonomic units (OTUs) were detected. The richness ranged between 8 and 33 cyanobacterial OTUs per sample, reflecting a high mat diversity. Leptolyngbya and Phormidium (c. 55% and 37% of the OTUs per mat) were dominant. Cyanobacterial community composition was similar between mats, particularly those obtained from closely adjacent locations. The cyanotoxin microcystin was detected in 26 of 27 mats (10–300 ng g-1 organic mass), while cylindrospermopsin, detected for the first time in Antarctica, was present in 21 of 30 mats (2–156 ng g-1 organic mass). The latter was confirmed via liquid chromatography-mass spectrometry and by the presence of the cyrAB and cyrJ genes. This study demonstrates the usefulness of pyrosequencing for characterizing diverse cyanobacterial communities, and confirms that cyanobacteria from extreme environments produce a similar range of cyanotoxins as their temperate counterparts

Microplastics Reduce Short-Term Effects of Environmental Contaminants. Part II: Polyethylene Particles Decrease the Effect of Polycyclic Aromatic Hydrocarbons on Microorganisms

Microplastic particles in terrestrial and aquatic ecosystems are currently discussed as an emerging persistent organic pollutant and as acting as a vector for hydrophobic chemicals. Microplastic particles may ultimately deposit and accumulate in soil as well as marine and freshwater sediments where they can be harmful to organisms. In this study, we tested the sensitivity of natural freshwater sediment bacterial communities (by genetic fingerprint) to exposure to microplastics (polyethylene, 2 and 20 mg/g sediment) and microplastics loaded with polycyclic aromatic hydrocarbons (PAHs, phenanthrene and anthracene), using a laboratory-based approach. After two weeks of incubation, the bacterial community composition from an unpolluted river section was altered by high concentrations of microplastics, whereas the community downstream of a wastewater treatment plant remained unchanged. Low microplastic concentrations loaded with phenanthrene or anthracene induced a less pronounced response in the sediment communities compared to the same total amount of phenanthrene or anthracene alone. In addition, biodegradation of the PAHs was reduced. This study shows, that microplastic can affect bacterial community composition in unpolluted freshwater sediments. Moreover, the results indicate that microplastics can serve as a vehicle for hydrophobic pollutants but bioavailability of the latter is reduced by the sorption to microplastics