TRYPANOSOMA-CRUZI INVOLVEMENT OF INTRACELLULAR CALCIUM IN MULTIPLICATION AND DIFFERENTIATION

Citation
Em. Lammel et al., TRYPANOSOMA-CRUZI INVOLVEMENT OF INTRACELLULAR CALCIUM IN MULTIPLICATION AND DIFFERENTIATION, Experimental parasitology, 83(2), 1996, pp. 240-249
Citations number
39
Categorie Soggetti
Parasitiology
Journal title
ISSN journal
00144894
Volume
83
Issue
2
Year of publication
1996
Pages
240 - 249
Database
ISI
SICI code
0014-4894(1996)83:2<240:TIOICI>2.0.ZU;2-9
Abstract
The possible role of intracellular Ca2+ level on Trypanosoma; cruzi di fferentiation was explored. The addition to epimastigotes of a Triatom a infestans intestinal homogenate, which that triggers off tile differ entiation to the infective metacyclic form, induced a sudden rise in [ Ca2+](i) from the basal value, 94 +/- 28 to 584 +/- 43 nmole/liter. Th is increase was not affected by the presence of EGTA in the medium. Tr ypsin-treated intestinal homogenate did not alter the [Ca2+](i) of epi mastigotes. Calmodulin inhibitors (Calmidazolium, Trifluoperazine, and Chlorpromazine) blocked differentiation. Although the calcium ionopho re ionomycin increased [Ca2+](i) to 342 +/- 29 nmole/liter, it was una ble to induce differentiation by itself. BAY K8644 and Methoxyverapami l (agonist and antagonist of Ca2+ channels, respectively) were unable to affect [Ca2+](i) by themselves, or when added to stimulated parasit es, and did not exert a stimulatory or inhibitory effect on morphogene sis. BAPTA/AM, a Ca2+ chelator, partially blocked the rise in [Ca2+](i ) and morphogenesis; this effect was reversed by ionomycin. The requir ement of intracellular Ca2+ on epimastigote multiplication was also ev aluated. The addition of EGTA to the culture medium led to a decrease in epimastigote multiplication till it practically ceased in the sixth passage. When such parasites were transferred to LIT they partially r ecovered the growth rate. Parasites from passages III, IV, and V in th e Ca2+-depleted medium maintained their basal [Ca2+](i), but when trea ted with the intestinal homogenate, the rise in [Ca-2+](i) was abrogat ed, Accordingly, the differentiation percentages of such parasites dro pped significantly completed With controls. (C) 1996 Academic Press, I nc.