Conservation of cation-transporting ATPase genes in Leishmania.

DNA fragments isolated from Leishmania donovani ATPase genes were used to analyze the organization and expression of cation transporting ATPase genes in L. donovani, Leishmania tropica, Leishmania mexicana, Leishmania braziliensis, Trypanosoma brucei and Trypanosoma cruzi. The ATPase loci in all Leishmania species contained a tandem pair of ATPase genes arranged in head-to-tail orientation and separated by approximately 2 kb.

Cysteine proteinases of parasitic protozoa.

Proteinases are involved with many processes in living organisms. In recent years, there has been increasing interest in elucidating the functions the enzymes perform in parasites. These studies have revealed that one class of proteinases, the cysteine proteinases, predominates in many parasitic protozoa.

Bloodstream and metacyclic variant surface glycoprotein gene expression sites of Trypanosoma brucei gambiense.

Trypanosoma brucei gambiense is the causative agent of chronic human sleeping sickness. Previous studies have indicated that T. b.

A cysteine proteinase cDNA from Trypanosoma brucei predicts an enzyme with an unusual C-terminal extension.

A cDNA for a Trypanosoma brucei cysteine proteinase has been cloned and sequenced. The deduced protein can be divided into four domains, based on homologies with other cysteine proteinases: the pre-, pro- and central regions show considerable homology to the cathepsin L class of mammalian enzymes, whilst the long C-terminal extension distinguishes the trypanosome enzyme from all mammalian cysteine proteinases reported. This 108 amino acid extension, which includes 9 contiguous prolines near the junction with the central domain, appears likely to be processed in part to produce the mature enzyme, and may be involved in targeting the protein within the cell.

A transcriptional analysis of the Trypanosoma brucei hsp83 gene cluster.

Ten to twelve copies of the 83-kDa heat-shock protein gene (hsp83) from Trypanosoma brucei are arranged in a head-to-tail tandem array of 2.8-kb repeat units, which are transcribed to give 2.6-kb mature mRNAs.

Two variant surface glycoprotein genes distinguish between different substrains of Trypanosoma brucei gambiense.

Trypanosoma brucei gambiense differs from other T. brucei subspecies in the stability and conservation of its bloodstream form antigenic repertoire. Two variant surface glycoprotein (VSG) cDNA clones corresponding to the antigens U1 and L2 were isolated from T.

Isolation and sequence of four small nuclear U RNA genes of Trypanosoma brucei subsp. brucei: identification of the U2, U4, and U6 RNA analogs.

Trypanosomes use trans splicing to place a common 39-nucleotide spliced-leader sequence on the 5' ends of all of their mRNAs. To identify likely participants in this reaction, we used antiserum directed against the characteristic U RNA 2,2,7-trimethylguanosine (TMG) cap to immunoprecipitate six candidate U RNAs from total trypanosome RNA. Genomic Southern analysis using oligonucleotide probes constructed from partial RNA sequence indicated that the four largest RNAs (A through D) are encoded by single-copy genes that are not closely linked to one another.

Leishmania mexicana: subcellular distribution of enzymes in amastigotes and promastigotes.

Glycosomes and mitochondrial vesicles from cultured promastigotes of Leishmania mexicana mexicana have been separated using isopycnic centrifugation on linear sucrose gradients. Hexokinase (EC 2.7.

Leishmania mexicana: enzyme activities of amastigotes and promastigotes and their inhibition by antimonials and arsenicals.

A major difference between the metabolism of Leishmania species amastigotes and cultured promastigotes was found in the area of CO2 fixation and phosphoenolpyruvate metabolism. Malate dehydrogenase (EC 1.1.

Purification of particulate malate dehydrogenase and phosphoenolpyruvate carboxykinase from Leishmania mexicana mexicana.

The particulate activities of Leishmania mexicana mexicana amastigote malate dehydrogenase (L-malate:NAD+ oxidoreductase, EC 1.1.1.

Subcellular localisation of purine-metabolising enzymes in Leishmania mexicana mexicana.

Leishmania mexicana mexicana cultured promastigotes were fractionated by isopycnic centrifugation on linear sucrose gradients. Guanine, hypoxanthine and xanthine phosphoribosyltransferase activities were found to be associated with glycosomes, whereas adenine phosphoribosyltransferase was cytosolic. 3'- and 5'-nucleotidases and IMP dehydrogenase were shown to be particulate, the former two possibly being associated with the plasma membrane, IMP dehydrogenase with the endoplasmic reticulum.