The Crithidia fasciculata RNH1 gene encodes an RNase H, an enzyme that specifically degrades the RNA strand of RNA-DNA hybrids. The RNH1 gene is contained within an open reading frame (ORF) predicted to encode a protein of 53.7 kDa. Previous work has shown that RNH1 expresses two proteins: a 38 kDa protein and a 45 kDa protein which is enriched in kinetoplast extracts. Epitope tagging of the C-...

In a recent paper (5), Noyes et al. discussed a nested-PCRbased approach for identification and analysis of Leishmania kinetoplast DNA (kDNA) minicircle classes using the analysis of minicircle variable-region (VR) restriction profiles. The kDNA of trypanosomatids consists of catenated minicircle (approximately 5 3 10 to 5 3 10 per associate) and maxicircle (20 to 50 per associate) molecules (8...

Multiplication of Trypanosoma pacifica was common in the fish host from observations of live flagellates and Giemsa-stained blood smears. Multiplication began with the elongation of the kinetoplast, thickening of the posterior portion of the body, and appearance of a new flagellum near the kinetoplast. The new flagellum was very rigid when less than 3 microm in length, but it became flexible as...

A 414-base pair fragment from a Leishmania tarentolae kinetoplast DNA minicircle has unusual physical properties. We reported previously that in comparison to phi X174 and pBR322 control fragments, the kinetoplast fragment behaves in gel electrophoresis, gel filtration, and electric dichroism experiments as if it has an unusually compact conformation. We accounted for these unusual properties b...

The sequences of seven new Trypanosoma brucei kinetoplast DNA minicircles were obtained. A detailed comparative analysis of these sequences and those of the 18 complete kDNA minicircle sequences from T. brucei available in the database was performed. These 25 different minicircles contain 86 putative gRNA genes. The number of gRNA genes per minicircle varies from 2 to 5. In most cases, the gene...

A fully kinetoplastic strain of an antigenic variant of Trypanosoma equiperdum has been made dyskinetoplastic by successive treatments of infected rats with ethidium bromide or acriflavine. After seven passages in the absence of the dye, the loss of kinetoplast DNA (kDNA) is stable and complete as shown by analytical ultracentrifugation, CsCl-dye gradients, and the reassociation kinetics of in ...