• Medientyp: E-Artikel
  • Titel: Mapping the Distribution of Cysts from the Toxic Dinoflagellate Cochlodinium polykrikoides in Bloom-Prone Estuaries by a Novel Fluorescence In Situ Hybridization Assay
  • Beteiligte: Hattenrath-Lehmann, Theresa K.; Zhen, Yu; Wallace, Ryan B.; Tang, Ying-Zhong; Gobler, Christopher J.
  • Erschienen: American Society for Microbiology, 2016
  • Erschienen in: Applied and Environmental Microbiology
  • Sprache: Englisch
  • DOI: 10.1128/aem.03457-15
  • ISSN: 0099-2240; 1098-5336
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  • Beschreibung: <jats:title>ABSTRACT</jats:title> <jats:p> <jats:named-content content-type="genus-species">Cochlodinium polykrikoides</jats:named-content> is a cosmopolitan dinoflagellate that is notorious for causing fish-killing harmful algal blooms (HABs) across North America and Asia. While recent laboratory and ecosystem studies have definitively demonstrated that <jats:named-content content-type="genus-species">Cochlodinium</jats:named-content> forms resting cysts that may play a key role in the dynamics of its HABs, uncertainties regarding cyst morphology and detection have prohibited even a rudimentary understanding of the distribution of <jats:named-content content-type="genus-species">C. polykrikoides</jats:named-content> cysts in coastal ecosystems. Here, we report on the development of a fluorescence <jats:italic>in situ</jats:italic> hybridization (FISH) assay using oligonucleotide probes specific for the large subunit (LSU) ribosomal DNA (rDNA) of <jats:named-content content-type="genus-species">C. polykrikoides</jats:named-content> . The LSU rDNA-targeted FISH assay was used with epifluorescence microscopy and was iteratively refined to maximize the fluorescent reaction with <jats:named-content content-type="genus-species">C. polykrikoides</jats:named-content> and minimize cross-reactivity. The final LSU rDNA-targeted FISH assay was found to quantitatively recover cysts made by North American isolates of <jats:named-content content-type="genus-species">C. polykrikoides</jats:named-content> but not cysts formed by other common cyst-forming dinoflagellates. The method was then applied to identify and map <jats:named-content content-type="genus-species">C. polykrikoides</jats:named-content> cysts across bloom-prone estuaries. Annual cyst and vegetative cell surveys revealed that elevated densities of <jats:named-content content-type="genus-species">C. polykrikoides</jats:named-content> cysts (&gt;100 cm <jats:sup>−3</jats:sup> ) during the spring of a given year were spatially consistent with regions of dense blooms the prior summer. The identity of cysts in sediments was confirmed via independent amplification of <jats:named-content content-type="genus-species">C. polykrikoides</jats:named-content> rDNA. This study mapped <jats:named-content content-type="genus-species">C. polykrikoides</jats:named-content> cysts in a natural marine setting and indicates that the excystment of cysts formed by this harmful alga may play a key role in the development of HABs of this species. </jats:p>
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