High diversity of microcystins in a Microcystis bloom from an Algerian lake

Bouhaddada, Ratiba; Nélieu, Sylvie; Nasri, Hichèm; Delarue, Ghislaine; Bouaı̈cha, Noureddine

doi:10.1016/j.envpol.2016.06.055

Cited by 57 publications

(38 citation statements)

References 51 publications

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“…As a result of the large number of literature reports spanning over four decades of research, it can be difficult to glean accurate information on the total number of identified MCs. The phrase 'more than 100 microcystin congeners' is still often used in the literature [12,[38][39][40][41] however estimates as high as 248 known MCs have recently been published [42]. In this review, we update this number to 279 and describe the methods by which this structural elucidation was carried out.…”

Section: Introductionmentioning

confidence: 99%

Structural Diversity, Characterization and Toxicology of Microcystins

Bouaı̈cha

Miles

Beach

et al. 2019

Toxins

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319

192

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Hepatotoxic microcystins (MCs) are the most widespread class of cyanotoxins and the one that has most often been implicated in cyanobacterial toxicosis. One of the main challenges in studying and monitoring MCs is the great structural diversity within the class. The full chemical structure of the first MC was elucidated in the early 1980s and since then, the number of reported structural analogues has grown steadily and continues to do so, thanks largely to advances in analytical methodology. The structures of some of these analogues have been definitively elucidated after chemical isolation using a combination of techniques including nuclear magnetic resonance, amino acid analysis, and tandem mass spectrometry (MS/MS). Others have only been tentatively identified using liquid chromatography-MS/MS without chemical isolation. An understanding of the structural diversity of MCs, the genetic and environmental controls for this diversity and the impact of structure on toxicity are all essential to the ongoing study of MCs across several scientific disciplines. However, because of the diversity of MCs and the range of approaches that have been taken for characterizing them, comprehensive information on the state of knowledge in each of these areas can be challenging to gather. We have conducted an in-depth review of the literature surrounding the identification and toxicity of known MCs and present here a concise review of these topics. At present, at least 279 MCs have been reported and are tabulated here. Among these, about 20% (55 of 279) appear to be the result of chemical or biochemical transformations of MCs that can occur in the environment or during sample handling and extraction of cyanobacteria, including oxidation products, methyl esters, or post-biosynthetic metabolites. The toxicity of many MCs has also been studied using a range of different approaches and a great deal of variability can be observed between reported toxicities, even for the same congener. This review will help clarify the current state of knowledge on the structural diversity of MCs as a class and the impacts of structure on toxicity, as well as to identify gaps in knowledge that should be addressed in future research.

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Section: Introductionmentioning

confidence: 99%

Structural Diversity, Characterization and Toxicology of Microcystins

Bouaı̈cha

Miles

Beach

et al. 2019

Toxins

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319

192

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“…In the surface waters of the northeast Algerian, several studies have shown that cyanobacterial blooms containing microcyst ins were dominated by the genus Microcystic [4,5,6,7,8,9]. Our investigation in the Cheffia dam has shown that this reservoir has seasonal cyanobacterial blooms that start in summer and last into autumn, however Lake Oubeira has persistent blooms that encompass all seasons.…”

Section: Biodiversity Of Toxic Cyanobacteria and Their Toxins In The mentioning

confidence: 87%

Blooms of Toxic Cyanobacteria in Freshwater in Algeria

Nasri¹,

Bouaı̈cha²

2017

Water conserv. manag.

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When water temperature and irradiance as well as meteorological conditions and nutrient supply are favourable, cyanobacteria can flourish in lakes and rivers where they can produce blooms usually in summer to late autumn, in both subtropical and temperate latitudes. Several of which are toxic and produce specifically hepatotoxins type microcyst ins. Studies undertaken in dams and natural lakes, particularly in the lake Oubeira and the dam Cheffia (East-Algeria), showed that these media evolve quickly to eutrophication, following an increased productivity stimulated continuously by the fertilizer contributions and a change of increasingly dry climate. The appearance of toxic cyanobacteria in these water bodies either used as drinking water or for recreational purposes may present serious health risks for the human population. The biodiversity of toxic cyanobacteria and their toxins, undertaken in the lake Oubeira and the dam Cheffia, showed that the Microcystic is the most implied genus in the formation of cyanobacterial blooms. The concentrations of microcyst ins, estimated by the PP2A method, are very high (28 mg/L) during the period of cyanobacterial blooms in summer and at the beginning of autumn. The MC-LR, MC-YR, and MC-RR are the most common microcyst in congeners identified in these water bodies.Cite this article as: Hichem Nasri and Noureddine Bouaïcha (2017). Blooms Of Toxic CyanobacteriaIn Freshwater In Algeria. Water Conservation and Management (WCM), 1(2):05-06.

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“…The first one is found, for example, in the Pseudomonas syringae (a plant pathogen) genome, as a virulence factor (Syringomycin E) [55] which also has antifungal activity against Saccharomyces cerevisiae [56]. On the other hand, Microcystin is a class of toxins produced by freshwater Cyanobacteria species [57] and it can be produced in large quantities during massive bloom events [58]. Due to the taxonomical classification of the bin and the higher number of domains similar to Syringomycin, however, it is more likely that the product encoded by this cluster is functionally close to the latter pathway.…”

Section: Discussionmentioning

confidence: 99%

Recovering genomic clusters of secondary metabolites from lakes: a Metagenomics 2.0 approach

Cuadrat

Ionescu

Dávila

et al. 2017

Preprint

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BackgroundMetagenomic approaches became increasingly popular in the past decades due to decreasing costs of DNA sequencing and bioinformatics development. So far, however, the recovery of long genes coding for secondary metabolism still represents a big challenge. Often, the quality of metagenome assemblies is poor, especially in environments with a high microbial diversity where sequence coverage is low and complexity of natural communities high. Recently, new and improved algorithms for binning environmental reads and contigs have been developed to overcome such limitations. Some of these algorithms use a similarity detection approach to classify the obtained reads into taxonomical units and to assemble draft genomes. This approach, however, is quite limited since it can classify exclusively sequences similar to those available (and well classified) in the databases.In this work, we used draft genomes from Lake Stechlin, north-eastern Germany, recovered by MetaBat, an efficient binning tool that integrates empirical probabilistic distances of genome abundance, and tetranucleotide frequency for accurate metagenome binning. These genomes were screened for secondary metabolism genes, such as polyketide synthases (PKS) and non-ribosomal peptide synthases (NRPS), using the Anti-SMASH and NAPDOS workflows.ResultsWith this approach we were able to identify 243 secondary metabolite clusters from 121 genomes recovered from the lake samples. A total of 18 NRPS, 19 PKS and 3 hybrid PKS/NRPS clusters were found. In addition, it was possible to predict the partial structure of several secondary metabolite clusters allowing for taxonomical classifications and phylogenetic inferences.ConclusionsOur approach revealed a great potential to recover and study secondary metabolites genes from any aquatic ecosystem.

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High diversity of microcystins in a Microcystis bloom from an Algerian lake

Cited by 57 publications

References 51 publications

Structural Diversity, Characterization and Toxicology of Microcystins

Structural Diversity, Characterization and Toxicology of Microcystins

Blooms of Toxic Cyanobacteria in Freshwater in Algeria

Recovering genomic clusters of secondary metabolites from lakes: a Metagenomics 2.0 approach

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