TY - JOUR
T1 - Casting a net
T2 - Fibres produced by Microcystis sp. in field and laboratory populations
AU - Harel, Moshe
AU - Weiss, Gad
AU - Daniel, Einat
AU - Wilenz, Avraham
AU - Hadas, Ora
AU - Sukenik, Assaf
AU - Sedmak, Bojan
AU - Dittmann, Elke
AU - Braun, Sergei
AU - Kaplan, Aaron
PY - 2012/6
Y1 - 2012/6
N2 - The reasons for the apparent dominance of the toxic cyanobacterium Microcystis sp., reflected by its massive blooms in many fresh water bodies, are poorly understood. We show that in addition to a large array of secondary metabolites, some of which are toxic to eukaryotes, Microcystis sp. secretes large amounts of fibrous exopolysaccharides that form extremely long fibres several millimetres in length. This phenomenon was detected in field and laboratory cultures of various Microcystis strains. In addition, we have identified and characterized three of the proteins associated with the fibres and the genes encoding them in Microcystis sp. PCC 7806 but were unable to completely delete them from its genome. Phylogenetic analysis of the most abundant one, designated IPF-469, showed its presence only in cyanobacteria. Its closest relatives were detected in Synechocystis sp. PCC 6803 and in Cyanothece sp. strains; in the latter the genomic organization of the IPF-469 was highly conserved. IPF-469 and the other two proteins identified here, a haloperoxidase and a haemolysin-type calcium-binding protein, may be part of the fibres secretion pathway. The biological role of the fibres in Microcystis sp. is discussed.
AB - The reasons for the apparent dominance of the toxic cyanobacterium Microcystis sp., reflected by its massive blooms in many fresh water bodies, are poorly understood. We show that in addition to a large array of secondary metabolites, some of which are toxic to eukaryotes, Microcystis sp. secretes large amounts of fibrous exopolysaccharides that form extremely long fibres several millimetres in length. This phenomenon was detected in field and laboratory cultures of various Microcystis strains. In addition, we have identified and characterized three of the proteins associated with the fibres and the genes encoding them in Microcystis sp. PCC 7806 but were unable to completely delete them from its genome. Phylogenetic analysis of the most abundant one, designated IPF-469, showed its presence only in cyanobacteria. Its closest relatives were detected in Synechocystis sp. PCC 6803 and in Cyanothece sp. strains; in the latter the genomic organization of the IPF-469 was highly conserved. IPF-469 and the other two proteins identified here, a haloperoxidase and a haemolysin-type calcium-binding protein, may be part of the fibres secretion pathway. The biological role of the fibres in Microcystis sp. is discussed.
UR - http://www.scopus.com/inward/record.url?scp=84860856286&partnerID=8YFLogxK
U2 - 10.1111/j.1758-2229.2012.00339.x
DO - 10.1111/j.1758-2229.2012.00339.x
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AN - SCOPUS:84860856286
SN - 1758-2229
VL - 4
SP - 342
EP - 349
JO - Environmental Microbiology Reports
JF - Environmental Microbiology Reports
IS - 3
ER -