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Oxidative stress in the cyanobacterium microcystis aeruginosa PCC 7813: comparison of different analytical cell stress detection assays.

Menezes, Indira; Maxwell-McQueeney, Declan; Capelo-Neto, Jos�; Pestana, Carlos J.; Edwards, Christine; Lawton, Linda A.


Declan Maxwell-McQueeney

Jos� Capelo-Neto


Cyanobacterial blooms are observed when high cell densities occur and are often dangerous to human and animal health due to the presence of cyanotoxins. Conventional drinking water treatment technology struggles to efficiently remove cyanobacterial cells and their metabolites during blooms, increasing costs and decreasing water quality. Although field applications of hydrogen peroxide have been shown to successfully suppress cyanobacterial growth, a rapid and accurate measure of the effect of oxidative stress on cyanobacterial cells is required. In the current study, H2O2 (5 and 20 mg L-1) was used to induce oxidative stress in Microcystis aeruginosa PCC 7813. Cell density, quantum yield of photosystem II, minimal fluorescence and microcystin (MC-LR, -LY, -LW, -LF) concentrations were compared when evaluating M. aeruginosa cellular stress. Chlorophyll content (determined by minimal fluorescence) decreased by 10% after 48 hours while cell density was reduced by 97% after 24 hours in samples treated with 20 mg L-1 H2O2. Photosystem II quantum yield (photosynthetic activity) indicated cyanobacteria cell stress within 6 hours, which was considerably faster than the other methods. Intracellular microcystins (MC-LR, -LY, -LW and -LF) were reduced by at least 96% after 24 hours of H2O2 treatment. No increase in extracellular microcystin concentration was detected, which suggests that the intracellular microcystins released into the surrounding water were completely removed by the hydrogen peroxide. Thus, photosynthetic activity was deemed the most suitable and rapid method for oxidative cell stress detection in cyanobacteria, however, an approach using combined methods is recomended for efficient water treatment management.


MENEZES, I., MAXWELL-MCQUEENEY, D., CAPELO-NETO, J., PESTANA, C.J., EDWARDS, C. and LAWTON, L.A. 2021. Oxidative stress in the cyanobacterium Microcystis aeruginosa PCC 7813: comparison of different analytical cell stress detection assays. Chemosphere [online], 269, article ID 128766. Available from:

Journal Article Type Article
Acceptance Date Oct 25, 2020
Online Publication Date Oct 28, 2020
Publication Date Apr 30, 2021
Deposit Date Oct 30, 2020
Publicly Available Date Oct 29, 2021
Journal Chemosphere
Print ISSN 0045-6535
Electronic ISSN 1879-1298
Publisher Elsevier
Peer Reviewed Peer Reviewed
Volume 269
Article Number 128766
Keywords Cyanobacteria; Fluorescence; Microcystin; Water treatment; Hydrogen peroxide
Public URL


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