Patricia del Arenal, M.Sc.

Respiratory system of Taenia crassiceps

OBJECTIVES

• To identify the pathways that participate in the aerobe metabolism of the Taenia crassiceps cysticercus.
• To identify the alternate pathways of aerobe metabolism of the Taenia crassiceps cysticercus.
• To corroborate the presence of cytochrome "o" and define its participation as alternate terminal oxidase.
• To define the bifurcation sites of the alternate pathways.
• To identify the type(s) of quinone that form(s) part of the respiratory chain of this organism.

SUMMARY

Taenia crassiceps is a cestode which, in its adult form, is a parasite of the red fox and, in its larva form, of wild rodents. During its life cycle, this organism has to adapt itself to media with different O2 pressures, to which end it has a metabolism that can act in an aerobe and anaerobe way.

Based on studies with inhibitors, we have found the presence of alternate pathways in the electron transportation chain in the cysticercus of this Taenia. We propose at least two alternate chains in which an "o" type cytochrome oxidase in addition to the cytochrome oxidase a/a3 and a dehydrogenase NADH resistant to retenone would seem to be involved.

The participation and regulation of these components will allow us to determine, on the one hand, the adaptation capacity of this organism to different media and, on the other, the pathways it does not share with the host and that could be the target of some drug.

PARTICIPANTS

BIBLIOGRAPHY

• 1. Escamilla, J.E., Barquera, B., Ramírez, R., García-Horsman and Arenal del. I. P. ( 1988). Role of menaquinone in inactivation and activation of the Bacillus cereus forespore respiratory system. J. Bact. 170:5908-5912.
• 2. Del Arenal Mena I.P. (1995) Metabolismo energético en helmintos parásitos. Mensaje Bioquímico vol. XIX (Martínez, M. Eds) Fac. de Medicina, UNAM, Mexico City. 119-134.
• 3. Del Arenal Mena I.P. and Escamilla M.J.E. (In press) Taenia crassiceps: Respiratory pathways in the cysticerci.