Journal Article

Sulphide Resistance in the Cyanobacterium Microcystis aeruginosa

Mariné, Mariona Hernández, Bañares-España, Elena, Reul, Andreas, del Mar Fernández-Arjona, María, García-Sánchez, María Jesús, Hernández-López, Miguel, Flores-Moya, Antonio

2016

Overview

The cyanobacterium Microcystis aeruginosa is a mesophilic freshwater organism, which cannot tolerate sulphide. However, it was possible to isolate a sulphideresistant (S r ) mutant strain that was able to survive in a normally lethal medium sulphide. In order to evaluate the cost of the mutation conferring sulphide resistance in the S r strain of M. aeruginosa, the morphology and the photosynthetic performance were compared to that found in the wild-type, sulphide-sensitive (S s ) strain. An increase in size and a disrupted morphology was observed in S r cells in comparison to the S s counterpart. Phycoerythrin and phycocyanin levels were higher in the S r than in the S s cells, whereas a higher carotenoid content, per unit volume, was found in the S s strain. The irradiance-saturated photosynthetic oxygen-production rate (GPRmax) and the photosynthetic efficiency (measured both by oxygen production and fluorescence,αGPR and αETR) were lower in the S r strain than in the wild-type. These results appear to be the result of package effect. On the other hand, the S r strain showed higher quantum yield of nonphotochemical quenching, especially those regulated mechanisms (estimated throughout q N and Y(NPQ)) and a significantly lower slope in the maximum quantum yield of lightadapted samples ( F v ' / F m ' ) compared to the S s strain. These findings point to a change in the regulation of the quenching of the transition states (q T ) in the S r strain which may be generated by a change in the distribution of thylakoidal membranes, which somehow could protect metalloenzymes of the electron transport chain from the lethal effect of sulphide.

• Publisher: Springer Science + Business Media,Springer US,Springer Nature B.V
• Subject: Biomedical and Life Sciences / Brackish / Carotenoids / Carotenoids - analysis / Carotenoids - metabolism / Chlorophyll - metabolism / Comparative analysis / Comparative studies / Cyanobacteria / Cyanobacterium (genus) / Ecology / Electron transport / Electron transport chain / ENVIRONMENTAL MICROBIOLOGY / Fluorescence / Fresh Water - microbiology / Freshwater / Freshwater organisms / Geoecology/Natural Processes / Inland water environment / Irradiance / Lethal effects / Life Sciences / Membranes / Microbial Ecology / Microbiology / Microcystis / Microcystis - drug effects / Microcystis - genetics / Microcystis - metabolism / Microcystis - ultrastructure / Microcystis aeruginosa / Microscopy, Electron, Transmission / Morphology / mutants / Mutation / Nature Conservation / Oxygen / Oxygen - metabolism / Oxygen production / Photochemicals / Photochemistry / Photosynthesis / Photosystem II Protein Complex - metabolism / Phycocyanin / Phycocyanin - analysis / phycoerythrin / Phycoerythrin - analysis / Quenching / Resistant mutant / Spain / Sulfides / Sulfides - pharmacology / Sulphides / Water Quality/Water Pollution