In vitro leishmanicidal activity of Tityus discrepans scorpion venom.
Leishmania parasites are sensitive to peptides with antimicrobial and ion-channel inhibitory activity. Because scorpion venoms are rich sources of such peptides, the leishmanicidal effect of Tityus discrepans venom was investigated. A negative correlation between cell growth and venom concentration was observed for venom-treated cultures of Leishmania (L.) mexicana mexicana promastigotes; 50% growth inhibition was obtained at 0.4 microg/ml. Light microscopy showed rounded, highly vacuolated L. (L.) m. mexicana cells with impaired flagellar motion after 15 min of incubation at 35 microg/ml. Ultrastructural studies confirmed an intense cytoplasm vacuolation and also enlargement of the flagellar pocket. Survival rates for New World Leishmania promastigotes (75% venom effective concentration, microg/ml) obtained after acute (1 h) venom toxicity tests were: L. (L.) m. mexicana (2.3), Leishmania (V.) braziliensis (11.3), and Leishmania (L.) chagasi (56.2). Heat (90 degrees C) treatment of venom and fraction TdII abolished most of their leishmanicidal effect. Acute toxicity assays performed with Sephadex G-50 fractions indicated that leishmanicidal activity is associated with the venom lowest molecular mass components (2.8-7.4 kDa), as determined by MALDI-TOF mass spectrometry.
Institute of Experimental Medicine, Central University of Venezuela, Box 50587, Sabana Grande, Caracas 1051, Venezuela. borgesa@rect.ucv.ve
Adolfo
A
Borges
Sylvia
S
Silva
Huub J M
HJ
Op den Camp
Elena
E
Velasco
Marco
M
Alvarez
Marcelo J M
MJ
Alfonzo
Alicia
A
Jorquera
Leonardo
L
De Sousa
Olinda
O
Delgado
D000818:Animals; D007891:Leishmania / Q000145:classification / Q000187:drug effects* / Q000254:growth & development; D007892:Leishmania braziliensis / Q000187:drug effects* / Q000254:growth & development; D007894:Leishmania mexicana / Q000187:drug effects* / Q000254:growth & development; D021261:Parasitic Sensitivity Tests; D012604:Scorpion Venoms / Q000737:chemistry / Q000494:pharmacology*; D012605:Scorpions / Q000378:metabolism*; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
D012604:Scorpion Venoms; C003609:tityustoxin