BnSP-7 toxin, a basic phospholipase A2 from Bothrops pauloensis snake venom, interferes with proliferation, ultrastructure and infectivity of Leishmania (Leishmania) amazonensis.

This paper reports the effects of BnSP-7 toxin, a catalytically inactive phospholipase A2 from Bothrops pauloensis snake venom, on Leishmania (Leishmania) amazonensis. BnSP-7 presented activity against promastigote parasite forms both in the MTT assay, with IC50 of 58.7 µg mL(-1) of toxin, and a growth curve, inhibiting parasite proliferation 60-70% at concentrations of 50-200 µg mL(-1) of toxin 96 h after treatment. Also, the toxin presented effects on amastigotes, reducing parasite viability by 50% at 28.1 µg mL(-1) and delaying the amastigote-promastigote differentiation process. Ultrastructural studies showed that BnSP-7 caused severe morphological changes in promastigotes such as mitochondrial swelling, nuclear alteration, vacuolization, acidocalcisomes, multiflagellar aspects and a blebbing effect in the plasma membrane. Finally, BnSP-7 interfered with the infective capacity of promastigotes in murine peritoneal macrophages, causing statistically significant infectivity-index reductions (P < 0.05) of 20-35%. These data suggest that the BnSP-7 toxin is an important tool for the discovery of new parasite targets that can be exploited to develop new drugs for treating leishmaniasis.

Oral lesion in leprosy: borderline tuberculoid diagnosis based on detection of Mycobacterium leprae DNA by qPCR.

Oral lesions are rarely reported in paucibacillary forms of leprosy. We report here a case with an erythematous hyposensitive lesion in the palate and no skin lesions. In addition to routine tests, biopsies of the lesion in the palate and of clinically normal surrounding areas were performed and subjected to real-time PCR for detection of Mycobacterium leprae DNA. The biopsy of the oral lesion was positive for bacilli DNA, followed by positive serum anti-PGL-1 and Mitsuda test, but with negative histopathology. The patient was diagnosed with a borderline tuberculoid form. After multidrug therapy the lesion had significantly regressed and the bacilli DNA detection in the former lesion was negative. The bacilli DNA detection in an oral lesion by real-time PCR not only improved leprosy diagnosis, but also helped in the classification of clinical form, and in the establishment of the appropriate therapeutic regime.