A Colpoda aspera isolate from animal faeces: In vitro cultivation and identification

A colpodean ciliate was found in the faeces of experimental rabbits. It was initially cultivated in medium mixed with 2% (w/v) rabbit faeces. Subsequently, two chemically defined media, designated CA-1 and CA-2, were found to be suitable for axenical cultivation of the ciliate. The maximum abundance of the ciliate isolate in the CA media was 1-2 × 10(5) cells/ml. The ciliate isolate was further identified with silver impregnation and molecular analysis. Features of the left oral polykinetid, somatic dikinetids, and sliverline pattern were similar to those of Colpoda aspera as described by Foissner (1993). The 18S small subunit ribosomal RNA gene of the ciliate isolate shared 99% sequence identity with that of C. aspera, with 100% coverage, and formed a sister clade in the phylogenetic tree with the reference C. aspera isolate. In addition, the trophozoite of C. aspera could proliferate over a temperature range from 25-37°C. When resting cysts were cultivated in CA-1 medium at 30-35°C, 98.2% of the trophozoites were detached from the cyst wall after 7 h.