Cutaneous leishman iasis: iso-enzyme charcterisation of leishmania tropica

In order to identify and characterise the organisms responsible for Cutaneous Leishmaniasis, parasites were isolated from active lesions, grown in-vitro cultures and identified by iso-enzyme characterisation. Thirteen isolates from different patients were typed as L. tropica. Seven of these isolates were from Afghan refugees encamped in the suburbs of Islamabad, 3 were from patients in Multan, 1 was from a patient from Azad Jammu and Kashmir and 1 was from Besham [Swat, NWFP]. The study confirms the presence of anthroponotic Cutaneous Leishamaniasis caused by L. Tropica in Pakistan

Leishmania enzyme activities in the promastigotes of leishmania tropica and leishmania major

A comparison was made between the enzyme activity in the promastigotes of Leishmania tropica and Leishmania major. Specific activities of hexokinase and lactate dehydrogenase in L. major were about 3 folds and glucose 6 phosphate dehydrogenase 8 folds those of in L. tropica. Acid phosphatase activity was 30% higher in L. major. No significant differences were, however, observed in alkaline phosphatase activity in the two species. The results of this study imply that the activity of acid phosphatase in a local acid environment, which results from hexokinase and lactate dehydrogenase activities, may be directly associated with the degree of virulence of leishmania

Heterogeneity of cysteine proteinases in Leishmania braziliensis and Leishmania major

Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) with acrylamide copolymerized with gelatin (substrate-SDS-PAGE) was used to compare promastigote proteinases from two Leishmania species (L. braziliensis and L. major-like). Substrate-SDS-PAGE resolved at least 6 distinct proteinase activities with relative molecular masses between 20 and 65 kDa. The profile of proteinase activity was the same for both species, although qualitative differences were observed. L. major-like expressed a low molecular weight (20 kDa) proteinase with maximum activity at pH 7.0, which was demonstrable from pH 5.0 to pH 8.0. The 20-kDa protease was recovered in the detergent phase of TX-114 and was inhibited by the sulfhydryl group-blocking reagent E-64 (2.5 mM) and the non-specific inhibitor iodoacetic acid (1 mM). Pepstatin (1 microM) and PMSF (2.5 mM) did not inhibit the 20-kDa enzyme. The present study suggests that both Leishmania species studied express hydrophobic cysteine proteases of different molecular weights, since about 2 x 10(7) parasites were analyzed in each lane and the proteolytic activity developed at 37 degrees C for 16 h

Extracellular dephosphorylation in the parasite, leishmania major / Desfosforilacion extracelular en el parasito, leishmania major

Leishmania major promastigotes were analyzed for the presence of protein phosphatase activity in intact cells and membrane-enriched fractions. Parasite phosphoprorylated in live cells with {*-32P} adenosine 5'-triphosphate (ATP) and an edogemous leishmanial ectokinase, were dephosphorylated by endogenous protein phosphatase like activity in intact cells and membrane-rich fractions. An alkaline phosphatase-like activity was also identified using the artificial substrate, p-nitrophenyl phosphate (pNPP). This activity was localized on the extracellular membrane of intact parasite, as well as in the particulate fraction of lysed cells. The phosphatase activity measure using pNPP had inhibition properties and a pH profile between protein phosphatases and general alkaline phosphatase. This study supports the observation that there is extracellular protein phosphorylation/dephosphorylation in L.major which may play a significant role in host-cell-parasite recognition and infection