A new identity of microcystins: Environmental endocrine disruptors? An evidence-based review

Cyanobacteria produce a wide range of structurally diverse cyanotoxins and bioactive cyanopeptides in freshwater, marine, and terrestrial ecosystems. The health significance of these metabolites, which include genotoxic- and neurotoxic agents, is confirmed by continued associations between the occurrence of animal and human acute toxic events and, in the long term, by associations between cyanobacteria and neurodegenerative diseases. Major mechanisms related to the neurotoxicity of cyanobacteria compounds include (1) blocking of key proteins and channels; (2) inhibition of essential enzymes in mammalian cells such as protein phosphatases and phosphoprotein phosphatases as well as new molecular targets such as toll-like receptors 4 and 8. One of the widely discussed implicated mechanisms includes a misincorporation of cyanobacterial non-proteogenic amino acids. Recent research provides evidence that non-proteinogenic amino acid BMAA produced by cyanobacteria have multiple effects on translation process and bypasses the proof-reading ability of the aminoacyl-tRNA-synthetase. Aberrant proteins generated by non-canonical translation may be a factor in neuronal death and neurodegeneration. We hypothesize that the production of cyanopeptides and non-canonical amino acids is a more general mechanism, leading to mistranslation, affecting protein homeostasis, and targeting mitochondria in eukaryotic cells. It can be evolutionarily ancient and initially developed to control phytoplankton communities during algal blooms. Outcompeting gut symbiotic microorganisms may lead to dysbiosis, increased gut permeability, a shift in blood-brain-barrier functionality, and eventually, mitochondrial dysfunction in high-energy demanding neurons. A better understanding of the interaction between cyanopeptides metabolism and the nervous system will be crucial to target or to prevent neurodegenerative diseases.

Section: Mechanisms Of Brain Toxicitymentioning

confidence: 99%

Freshwater Cyanobacterial Toxins, Cyanopeptides and Neurodegenerative Diseases

Nugumanova

Ponomarev

Askarova

et al. 2023

“…At the same time, Aravind et al mixed cyanobacteria mud with composite environmental induction material ECO-U100 in a ratio of 100:2 to obtain a non-toxic and pollution-free environmental organic fertilizer [ 56 ], which can significantly improve rice quality compared with chemical fertilizer. Therefore, in the process of resource utilization of cyanobacteria biogas fertilizer, MCs can be well degraded and will not cause such harm to the environment [ 57 ]. However, in this process, it is necessary to pay attention to the production of other harmful gases in the biogas production process, such as hydrogen sulfide (H 2 S), methyl mercaptan (CH 3 SH) and methyl sulfide (C 2 H 6 S), and the purity of anaerobic biogas fermentation needs to be improved by desulfurization [ 58 ].…”

Section: Exposure Pathways Of Mcs In the Process Of Resource Utilizationmentioning

confidence: 99%

Transmission of Microcystins in Natural Systems and Resource Processes: A Review of Potential Risks to Humans Health

Ren

Wang

Zhang

et al. 2023

The rapid rise of microcystins (MCs) poses a serious threat to global freshwater ecosystems and has become an important issue of global public health. MCs have considerable stability and are the most widely distributed hepatotoxins. It cannot only accumulate in aquatic organisms and transfer to higher nutrients and levels, but also be degraded or transferred during the resource utilization of cyanobacteria. No matter which enrichment method, it will lead to the risk of human exposure. This review summarizes the research status of MCs, and introduces the distribution of MCs in different components of aquatic ecosystems. The distribution of MCs in different aquatic organisms was summarized, and the potential risks of MCs in the environment to human safety were summarized. MCs have polluted all areas of aquatic ecosystems. In order to protect human life from the health threats caused by MCs, this paper also proposes some future research directions to promote MCs control and reduce human exposure to MCs.

“…With fossils dating back up to 3.6 billion years [3][4][5][6][7], these organisms are considered to have had a large influence on the evolution of our planet, such as through the generation of the oxygen atmosphere and the Great Oxidation Event [8][9][10][11]. More recently, cyanobacteria have also been shown to produce a large number of toxic compounds [12][13][14][15], including peptides, alkaloids and components of the cell wall, such as microcystins [16][17][18][19][20], cylindrospermopsins [21][22][23][24][25][26], anatoxin-a [27][28][29][30], anatoxin-a(S) (guanitoxin; [31][32][33][34][35][36][37]), saxitoxins [38][39][40][41][42], and LPS [43][44][45] as examples. With regard to human health, exposure to these toxins can occur through a wide range of exposure routes such as drinking water [46,47], the consumption of seafood in...…”

Section: Introductionmentioning

confidence: 99%

A Direct Analysis of β-N-methylamino-l-alanine Enantiomers and Isomers and Its Application to Cyanobacteria and Marine Mollusks

Metcalf,

Banack,

Wyatt

et al. 2023

Of the wide variety of toxic compounds produced by cyanobacteria, the neurotoxic amino acid β-N-methylamino-l-alanine (BMAA) has attracted attention as a result of its association with chronic human neurodegenerative diseases such as ALS and Alzheimer’s. Consequently, specific detection methods are required to assess the presence of BMAA and its isomers in environmental and clinical materials, including cyanobacteria and mollusks. Although the separation of isomers such as β-amino-N-methylalanine (BAMA), N-(2-aminoethyl)glycine (AEG) and 2,4-diaminobutyric acid (DAB) from BMAA has been demonstrated during routine analysis, a further compounding factor is the potential presence of enantiomers for some of these isomers. Current analytical methods for BMAA mostly do not discriminate between enantiomers, and the chiral configuration of BMAA in cyanobacteria is still largely unexplored. To understand the potential for the occurrence of D-BMAA in cyanobacteria, a chiral UPLC-MS/MS method was developed to separate BMAA enantiomers and isomers and to determine the enantiomeric configuration of endogenous free BMAA in a marine Lyngbya mat and two mussel reference materials. After extraction, purification and derivatization with N-(4-nitrophenoxycarbonyl)-l-phenylalanine 2-methoxyethyl ester ((S)-NIFE), both L- and D-BMAA were identified as free amino acids in cyanobacterial materials, whereas only L-BMAA was identified in mussel tissues. The finding of D-BMAA in biological environmental materials raises questions concerning the source and role of BMAA enantiomers in neurological disease.