Stenamoeba polymorpha, a New Species Isolated from Domesticated Horse Equus ferus caballus.

A new species of lobosean amoeba, Stenamoeba polymorpha n. sp., was isolated from the diarrheic stool of a domesticated horse in Great Falls Virginia, U.

Interrelationships of chromalveolates within a broadly sampled tree of photosynthetic protists.

The Chromalveolata "supergroup" is a massive assemblage of single-celled and multicellular protists such as ciliates and kelps that remains to be substantiated in molecular trees. Recent multigene analyses place chromalveolates into two major clades, the SAR (Stramenopiles, Alveolata, and Rhizaria) and the Cryptophyta+Haptophyta. Here we determined 69 new sequences from different chromalveolates to study the interrelationships of its constituent phyla.

Etiology of ulcerative lesions of Atlantic menhaden (Brevoortia tyrannus) from James River, Virginia.

We observed ulcerative lesions on live Atlantic menhaden, Brevoortia tyrannus, during ichthyofaunal sampling in the tidal James River in October 1999 (near Jamestown, VA, USA). Other synoptically collected fishes exhibited no signs of lesions or pre-ulcerative tissues. Live fish were classified as unremarkable (no dermal anomalies), pre-ulcerative (integument intact with boil-like swelling), and ulcerative (severe focal lesions).

Identification of amoebae implicated in the life cycle of Pfiesteria and Pfiesteria-like dinoflagellates.

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.

Two new small-subunit ribosomal RNA gene lineages within the subclass gymnamoebia.

Phylogenetic analysis of small-subunit ribosomal RNA gene sequences for gymnamoebae of the families Vexilliferidae, Paramoebidae, and Vannellidae identified two distinct lineages that are supported by gross morphological characters. This analysis indicates that paramoebids and vexilliferids are part of one lineage and that vannellids belong to another. A shared morphological character unique to the paramoebid/vexilliferid lineage members is the presence of dactylopodiate subpseudopodia.