Trypanosoma cruzi, the agent of Chagas' disease, alternates between different morphogenetic stages that face distinct physiological conditions in their invertebrate and vertebrate hosts, likely in the availability of glucose. While the glucose transport is well characterized in epimastigotes of T. cruzi, nothing is known about how the mammalian stages acquire this molecule. Herein glucose transport activity and expression were analyzed in the three developmental stages present in the vertebrate cycle of T. cruzi. The infective trypomastigotes showed the highest transport activity (V(max)=5.34+/-0.54 nmol/min per mg of protein; K(m)=0.38+/-0.01 mM) when compared to intracellular epimastigotes (V(max)=2.18+/-0.20 nmol/min per mg of protein; K(m)=0.39+/-0.01 mM). Under the conditions employed no transport activity could be detected in amastigotes. The gene of the glucose transporter is expressed at the mRNA level in trypomastigotes and in intracellular epimastigotes but not in amastigotes, as revealed by real-time PCR. In both trypomastigotes and intracellular epimastigotes protein expression could be detected by Western blot with an antibody raised against the glucose transporter correlating well with the transport activity measured experimentally. Interestingly, anti-glucose transporter antibodies showed a strong reactivity with glycosome and reservosome organelles. A comparison between proline and glucose transport among the intracellular differentiation forms is presented. The data suggest that the regulation of glucose transporter reflects different energy and carbon requirements along the intracellular life cycle of T. cruzi.

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The CSC markers might play an important role not only in CSC trait acquisition but also in tongue SCC development and progression.

Ionotropic P2X and metabotropic P2Y purinergic receptors are expressed in the central nervous system and participate in the synaptic process particularly associated with acetylcholine, GABA, and glutamate neurotransmission. As a result of activation, the P2 receptors promote the elevation of free intracellular calcium concentration as the main signaling pathway. Purinergic signaling is present in early stages of embryogenesis and is involved in processes of cell proliferation, migration, and differentiation. The use of new techniques such as knockout animals, in vitro models of neuronal differentiation, antisense oligonucleotides to induce downregulation of purinergic receptor gene expression, and the development of selective inhibitors for purinergic receptor subtypes contribute to the comprehension of the role of purinergic signaling during neurogenesis. In this review, we shall discuss the participation of purinergic receptors in developmental processes and in brain physiology, including neuron-glia interactions and pathophysiology.

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