Kinetoplast DNA (kDNA) was isolated from 56 stocks of Trypanosoma cruzi isolated from human patients, animals and insects from Brazil, Venezuela, Colombia and Costa Rica. Comparison of the patterns of digested kDNA on acrylamide gels led to the grouping of several stocks into two schizodemes. Schizodeme analysis was also performed using a set of 330-bp fragments representing all the variable re...

Besides the nicking-closing (topoisomerase I) activity, an ATP-dependent DNA topoisomerase is present in rat liver nuclei. The enzyme, partially purified, is able to catenate in vitro closed DNA circles in a magnesium-dependent, ATP-dependent, histone H1-dependent reaction, and to decatenate in vitro kinetoplast DNA networks to yield free minicircles in a magnesium-dependent and ATP-dependent r...

We demonstrate the genetic transfer of DNA between eukaryotes from different kingdoms. The mitochondrial kinetoplast DNA (kDNA) of the intracellular parasite Trypanosoma cruzi is transferred to human patients with Chagas disease. This transfer was reproduced experimentally in rabbits and chickens. The kDNA is integrated into the host genome. In the human chromosomes, five loci were identified a...

Three PCR assays for diagnosing leishmaniasis were compared and validated against parasite cultures and microscopic evaluation of stained tissue smears using 92 specimens from suspected cases of cutaneous leishmaniasis (CL) in Israel and the West Bank. Samples from imported and locally acquired disease were examined. The kinetoplast DNA (kDNA) PCR showed the highest sensitivity (98.7%) of any a...

Cesium chloride centrifugation of each of the DNAs extracted from eight strains of Crithidia revealed a main band at rho = 1.717 g/cm(3) and a satellite band varying from rho = 1.701 to 1.705 g/cm(3) for the different strains By electron microscopy each DNA was shown to include circular molecules, 0.69-0.80 micro in mean contour length, and large, topologically two-dimensional masses of DNA in ...

Two oligonucleotide primers Lsmc1 and Lsmv1 derived from the conserved and the variable region of a major class kinetoplast DNA (kDNA) minicircle (pLURkE3) of Leishmania strain UR6 were used for the polymerase chain reaction (PCR) in order to amplify a 461-bp fragment from the kDNAs of different Leishmania species. These primers amplify the specific fragment from the kDNAs of cutaneous species ...

The sequence-directed bent structure of kinetoplast DNA minicircles specifies a unique binding site for Crithidia fasciculata nicking enzyme. Binding of the purified enzyme to the bent structure results in the formation of a tight enzyme-DNA complex that is highly specific to curved DNA. Recognition of the binding site is not determined by the nucleotide sequence at the site of binding per se b...

BACKGROUND The causative agent of Chagas disease, Trypanosoma cruzi, is divided into 6 Discrete Typing Units (DTU): Tc I, IIa, IIb, IIc, IId and IIe. In order to assess the relative pathogenicities of different DTUs, blood samples from three different clinical groups of chronic Chagas disease patients (indeterminate, cardiac, megacolon) from Bolivia were analyzed for their circulating parasites...

Furamidine (DB75) and related unfused aromatic diamidines have proven useful for the treatment of parasitic infections. These compounds were primarily developed to combat infections by Pneumocystis carinii and African trypanosomes but they are also active against other parasites. Here we have investigated the in vitro effects of DB75 and its phenyl-substituted analog DB569 on two kinetoplastid ...

The Leishmania species cause a variety of human disease syndromes. Methods for diagnosis and species differentiation are insensitive and many require invasive sampling. Although quantitative PCR (qPCR) methods are reported for leishmania detection, no systematic method to quantify parasites and determine the species in clinical specimens is established. We developed a serial qPCR strategy to id...