title: Molecular characterization of cyanobacterial diversity in a shallow eutrophic lake.
abstract: We have studied the diversity of pelagic cyanobacteria in Lake Loosdrecht, The Netherlands, through recovery and analysis of small subunit ribosomal RNA gene sequences from lake samples and cyanobacterial isolates. We used an adapted protocol for specific amplification of cyanobacterial rDNA for denaturing gradient gel electrophoresis (DGGE) analysis. This protocol enabled direct comparison of cyanobacterial community profiles with overall bacterial profiles. The theoretical amplification specificity of the primers was supported by sequence analysis of DNA from excised DGGE bands. Sequences recovered from these bands, in addition to sequences obtained by polymerase chain reaction (PCR) and cloning from lake DNA as well as from cyanobacterial isolates from the lake, revealed a diverse consortium of cyanobacteria, among which are representatives of the genera Aphanizomenon, Planktothrix, Microcystis and Synechococcus. One numerically important and persistent cyanobacterium in the lake, Prochlorothrix hollandica, appeared to co-occur with an unknown but related species. However, the lake is dominated by filamentous species that originally have been termed 'Oscillatoria limnetica-like'. We show that this is a group of several related cyanobacteria, co-occurring in the lake, which belong to the Limnothrix/Pseudanabaena group. The available variation among the coexisting strains of this group can explain the persistent dominance of the group under severe viral pressure.
authors.affiliation: Centre for Limnology, NIOO-KNAW Netherlands Institute of Ecology, Rijksstraatweg 6, 3631 AC Nieuwersluis, The Netherlands. g.zwart@nioo.knaw.nl
authors.forename: Gabriel
authors.initials: G
authors.lastname: Zwart
authors.forename: Miranda P
authors.initials: MP
authors.lastname: Kamst-van Agterveld
authors.forename: Irene
authors.initials: I
authors.lastname: van der Werff-Staverman
authors.forename: Ferry
authors.initials: F
authors.lastname: Hagen
authors.forename: Hans L
authors.initials: HL
authors.lastname: Hoogveld
authors.forename: Herman J
authors.initials: HJ
authors.lastname: Gons
mesh_terms: D015373:Bacterial Typing Techniques; D000458:Cyanobacteria / Q000145:classification* / Q000235:genetics; D004275:DNA, Ribosomal / Q000032:analysis / Q000235:genetics; D004591:Electrophoresis, Polyacrylamide Gel / Q000379:methods; D005618:Fresh Water / Q000382:microbiology*; D010802:Phylogeny; D016133:Polymerase Chain Reaction; D012336:RNA, Ribosomal, 16S / Q000032:analysis* / Q000235:genetics; D017422:Sequence Analysis, DNA
chemical_list: D004275:DNA, Ribosomal; D012336:RNA, Ribosomal, 16S