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Identification of Amoebae Implicated in the Life Cycle of Pfiesteria and Pfiestena‐ Like Dinoflagellates
Author(s) -
PEGLAR MICHAEL T.,
NERAD THOMAS A,
ANDERSON O. ROGER,
GILLEVET PATRICK M.
Publication year - 2004
Publication title -
journal of eukaryotic microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.067
H-Index - 77
eISSN - 1550-7408
pISSN - 1066-5234
DOI - 10.1111/j.1550-7408.2004.tb00290.x
Subject(s) - biology , dinoflagellate , protist , ciliate , protozoa , gymnodinium , epilimnion , algae , fish kill , ecology , algal bloom , isolation (microbiology) , zoology , microbiology and biotechnology , phytoplankton , eutrophication , biochemistry , hypolimnion , nutrient , gene
This study was undertaken to assess whether amoebae commonly found in mesohaline environments are in fact stages in the life cycles of Pfiesteria and Pfiesteria‐like dinoflagellates. Primary isolations of amoebae and dinoflagellates were made from water and sediment samples from five tributaries of the Chesapeake Bay. Additional amoebae were also cloned from bioassay aquaria where fish mortality was attributed to Pfiesteria . Electron microscopy and small subunit (SSU) rRNA gene sequence analysis of these isolates clearly demonstrated that the commonly depicted amoeboid form of Pfiesteria is very likely a species of Korotnevella and is unrelated to Pfiesteria or Pfiesteria ‐like dinoflagellates. We have determined that the Pfiesteria and Pfiesteria ‐like dinoflagellates examined in this study undergo a typical homothallic life cycle without amoeboid stages. Furthermore, we have demonstrated that cloned amoebae sharing morphological characteristics described for stages in the life cycle of Pfiesteria do not transform into dino7.oites. The strict clonal isolation and cultivation techniques used in this study substantially support the conclusion that the amoebae and some of the flagellates depicted in the life cycle of Pfiesteria are environmental contaminants of the Pfiesteria culture system and that the Ambush Predator Hypothesis needs to be rigorously reevaluated.