Partial Ribosomal RNA Gene Sequences Research Articles

Granulomatous Nephritis and Meningoencephalomyelitis Caused by Halicephalobus gingivalis in a Pony Gelding

A ten-year-old Shetland pony gelding showed low appetite, ataxia, peculiar swaying, clouding of consciousness, and ultimately died. At necropsy, multiple coalescing granulomatous foci were detected in the kidneys, and small necrotic lesions were found in the cerebellum. Histologic examination of the renal tissue sections revealed extensive granuloma, and Halicephalobus gingivalis-like nematodes were seen. Similar nematodes were found in the granulomatous or necrotic lesions of the renal lymph nodes and cerebellum, and were also frequently detected in cerebrospinal meningovascular lesions. Morphologic features together with partial ribosomal RNA gene sequences of the nematodes in the lesions revealed that they were H. gingivalis. The present results indicated that H. gingivalis caused granulomatous nephritis and meningoencephalomyelitis in this pony gelding.

PCR protocols for genetic identification of dinoflagellates directly from single cysts and plankton cells

A simple preparation method and PCR protocol are described which allow successful PCR amplification of partial ribosomal RNA gene sequences from as little as one dinoflagellate cyst or vegetative cell. Amplification from single or small numbers of cysts can be applied to a range of morphologically identifiable cyst species and produces rDNA sequence data identical to those obtained from DNA extractions from cultured vegetative cells. Applications of the approach have the potential to aid phylogenetic studies of dinoflagellates and other microalgae by (1) improving taxonomic sampling of unculturable and heterotrophic species; (2) providing data to link cysts of unknown affinity with their potential planktonic cell counterparts; and (3) confirming the identification of cysts that cannot be germinated or are nonviable. Examples are presented where this method was used to confirm the identity and distribution of nonviable microreticulate cysts in coastal marine sediment samples, such as those of the recently described species Gymnodinium microreticulatum.