Abstract
Cyanobacteria are cosmopolitan photosynthetic prokaryotes that can form dense accumulations in aquatic environments. They are able to produce many bioactive metabolites, some of which are potentially endocrine disrupting compounds, i.e., compounds that interfere with the hormonal systems of animals and humans. Endocrine disruptors represent potential risks to both environmental and human health, making them a global challenge. The aim of this study was to investigate the potential endocrine disrupting activities with emphasis on estrogenic effects of extracts from cultures of Microcystis or Planktothrix species. We also assessed the possible role of microcystins, some of the most studied cyanobacterial toxins, and thus included both microcystin-producing and non-producing strains. Extracts from 26 cyanobacterial cultures were initially screened in estrogen-, androgen-, and glucocorticoid-responsive reporter-gene assays (RGAs) in order to identify endocrine disruption at the level of nuclear receptor transcriptional activity. Extracts from selected strains were tested repeatedly in the estrogen-responsive RGAs, but the observed estrogen agonist and antagonist activity was minor and similar to that of the cyanobacteria growth medium control. We thus focused on another, non-receptor mediated mechanism of action, and studied the 17β-estradiol (natural estrogen hormone) biotransformation in human liver microsomes in the presence or absence of microcystin-LR (MC-LR), or an extract from the MC-LR producing M. aeruginosa PCC7806 strain. Our results show a modulating effect on the estradiol biotransformation. Thus, while 2-hydroxylation was significantly decreased following co-incubation of 17β-estradiol with MC-LR or M. aeruginosa PCC7806 extract, the relative concentration of estrone was increased.
Highlights
Cyanobacteria are cosmopolitan photosynthetic prokaryotes, known as “blue-green algae”.In favorable conditions they can form dense blooms [1], most often in freshwater, and in brackish and marine water environments [1,2,3].Toxins 2020, 12, 228; doi:10.3390/toxins12040228 www.mdpi.com/journal/toxinsToxins 2019, 11, x FOR PEER REVIEWToxins 2020, 12, 228 environments [1,2,3]
In the first part of the study we focused on effects on estrogen, androgen, and glucocorticoid receptors
MCs or Microcystis spp., we expected that extracts from visually dense cultures of the cyanobacteria would give a clear response in the estrogen-responsive Reporter gene assays (RGAs) provided that there are cyanobacterial metabolites or constituents that induce effects at the receptor level
Summary
Toxins 2020, 12, 228 environments [1,2,3] During such blooms, cyanobacteria may release a large variety of bioactive metabolites, including well-known cyanotoxins [1,4]. They may have negative effects on During such blooms, cyanobacteria may release a large variety of bioactive metabolites, including water safety and quality (drinking, bathing, fishing, and recreational uses) and result in harm to well-known cyanotoxins [1,4] They may have negative effects on water safety and quality invertebrates and vertebrates including humans [2,5,6,7,8,9]. Different types of cyanobacterial toxins are (drinking, bathing, fishing, and recreational uses) and result in harm to invertebrates and vertebrates classified according their toxicological target as hepatotoxins, dermatoxins
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
