RESUMEN
Based on morphological and molecular characterisation, four amoeba strains isolated from organs of freshwater fish were identified as Hartmannella vermiformis Page, 1967. Small subunit rRNA gene sequences of these strains expand the set of corresponding complete and almost complete sequences of this species to twelve. A new species-specific oligonucleotide probe inferred from recently available SSU rRNA gene sequences was designed and successfully tested in tissue lesions produced by one strain of H. vermiformis in experimentally infected fish.
Asunto(s)
Amebiasis/veterinaria , Enfermedades de los Peces/parasitología , Hartmannella/genética , Hartmannella/ultraestructura , Filogenia , Amebiasis/diagnóstico , Amebiasis/parasitología , Animales , Secuencia de Bases/genética , Enfermedades de los Peces/diagnóstico , Peces , Genes de ARNr/genética , Hartmannella/clasificación , Hartmannella/aislamiento & purificación , Hibridación Fluorescente in Situ/métodos , Funciones de Verosimilitud , Microscopía Electrónica/métodos , Datos de Secuencia Molecular , Análisis de Secuencia de ADNRESUMEN
A new species of amphizoic amoeba, Nuclearia pattersoni sp. n., isolated from gills of Rutilus rutilus L. is described. It is characterised by elongate flattened trophozoites of irregular shape. The longer dimension of their bodies is 13.2 (11.0-15.7) microm. Filopodia radiating mostly from the poles are 2 to 2.5 times longer than the body. The diameter of less frequently observed spherical trophozoites is 8.2-10.8 microm; their filopodia radiate to all directions. Cyst-like stages have shorter pseudopodia that arise from one pole only. The surface of locomotive forms from agar plate cultures has a thin amorphous glycocalyx, while most cells are covered by two layers of extracellular matrix. Mitochondria have flattened cristae, dictyosomes are located in the perinuclear zone. A conspicuous ultrastructural feature of the morphologically similar N. simplex, perinuclear striated band, is not present. Light microscopic and ultrastructural data are completed with the sequence of SSU rRNA gene and phylogenetic analysis including sequences of related taxa. The bacterial endosymbiont found in N. pattersoni type strain RR2G2 is assigned to the genus Rickettsia.