TRANSIENT ADENYLATE-CYCLASE ACTIVATION ACCOMPANIES DIFFERENTIATION OF TRYPANOSOMA-BRUCEI FROM BLOOD-STREAM TO PROCYCLIC FORMS

Pleomorphic bloodstream forms of Trypanosoma brucei differentiate synchronously into procyclic forms when cultivated at 27-degrees-C in the presence of citrate/cis-aconitate [22]. The activity of adenylate cyclase was monitored during this process. Two phases of transient stimulation were observed. The first phase occurred 6-10 h after the triggering of differentiation, a period which immediately follows the release of the bulk of the VSG and immediately precedes both the first cell division and the loss of the bloodstream-specific ESAG 4 transmembrane adenylate cyclase, The second phase occurred between 20 and 40 h, when the cells that emerged from the first division began to proliferate. These observations suggest that cAMP may be involved in differentiation/proliferation of the parasite.