The African trypanosomes undergo extensive development as they proceed through their life cycle, producing a range of stages with distinct functions. In response to the somewhat treacherous, extracellular environments occupied by trypanosomes in their rather different hosts mammals and tsetse flies elaborate survival mechanisms are utilized. The best known of these is antigenic variation (revie...

The transformation of Trypanosoma cruzi epimastigotes to the mammal infective metacyclic trypomastigotes (metacyclogenesis) can be performed in vitro under chemically defined conditions. Under these conditions, differentiating epimastigotes adhere to a surface before their transformation into metacyclic trypomastigotes. Scanning and transmission electron microscopy of adhered and non-adhered pa...

We study a classM of cyclically presented groups that includes both finite and infinite groups and is defined by a certain combinatorial condition on the defining relations. This class includes many finite metacyclic generalized Fibonacci groups that have been previously identified in the literature. By analysing their shift extensions we show that the groups in the class M are are coherent, su...

We show that if the fundamental group π of an inde-composable orientable P D 3-complex is the fundamental group of a finite graph of finite groups then the vertex groups have periodic cohomology and the edge groups are metacyclic. If the vertex groups all have cohomological period dividing 4 at most one is not dihedral, the edge groups are Z/2Z, and the underlying graph is a tree. We also ask w...