title: The localization of exogenous microcystin LR taken up by a non-microcystin producing cyanobacterium.
abstract: The effect of exogenous microcystin on non-microcystin producing cyanobacteria has not yet been extensively studied. Existing evidence for internalization of microcystin by cyanobacteria is based only on the presence of internalized radioisotopic label. Where a function or physiological role for microcystin has been proposed based on the molecule acting as a signalling molecule, the hypothetical function has not been demonstrated at the site of action in receiving cells. We therefore exposed Synechocystis PCC6803 to microcystin LR and showed that the microcystin-LR was both taken up by Synechocystis PCC6803 and localised in the thylakoid membranes, where it caused a decrease in photosystem II activity as has been shown for endogenous microcystin, without any negative effects on the cell's survival.
authors: Department of Biochemistry and Microbiology, Nelson Mandela Metropolitan University, PO Box 77000, Port Elizabeth, 6031, South Africa.
authors: Richard R
authors: RR
authors: Phelan
authors: Department of Biochemistry and Microbiology, Nelson Mandela Metropolitan University, PO Box 77000, Port Elizabeth, 6031, South Africa. Electronic address: tim.downing@nmmu.ac.za.
authors: Timothy G
authors: TG
authors: Downing
mesh_terms: D008387:Marine Toxins; D052998:Microcystins / Q000378:metabolism* / Q000494:pharmacology; D045332:Photosystem II Protein Complex / Q000187:drug effects; D046939:Synechocystis / Q000378:metabolism*; D020524:Thylakoids / Q000378:metabolism
chemical_list: D008387:Marine Toxins; D052998:Microcystins; D045332:Photosystem II Protein Complex; C057862:cyanoginosin LR
keywords: Cyanobacteria; Microcystin; Photosynthesis; Thylakoid