Evolutionary Adaptations of Parasitic Flatworms to Different Oxygen Tensions
Por:
Martinez-Gonzalez, Jose de Jesus, Guevara-Flores, Alberto, del Arenal Mena, Irene Patricia
Publicada:
1 jun 2022
Resumen:
During the evolution of the Earth, the increase in the atmospheric
concentration of oxygen gave rise to the development of organisms with
aerobic metabolism, which utilized this molecule as the ultimate
electron acceptor, whereas other organisms maintained an anaerobic
metabolism. Platyhelminthes exhibit both aerobic and anaerobic
metabolism depending on the availability of oxygen in their environment
and/or due to differential oxygen tensions during certain stages of
their life cycle. As these organisms do not have a circulatory system,
gas exchange occurs by the passive diffusion through their body wall.
Consequently, the flatworms developed several adaptations related to the
oxygen gradient that is established between the aerobic tegument and the
cellular parenchyma that is mostly anaerobic. Because of the aerobic
metabolism, hydrogen peroxide (H2O2) is produced in abundance. Catalase
usually scavenges H2O2 in mammals; however, this enzyme is absent in
parasitic platyhelminths. Thus, the architecture of the antioxidant
systems is different, depending primarily on the superoxide dismutase,
glutathione peroxidase, and peroxiredoxin enzymes represented mainly in
the tegument. Here, we discuss the adaptations that parasitic flatworms
have developed to be able to transit from the different metabolic
conditions to those they are exposed to during their life cycle.
Filiaciones:
Martinez-Gonzalez, Jose de Jesus:
Univ Nacl Autonoma Mexico, Fac Med, Dept Bioquim, Mexico City 04510, DF, Mexico
Guevara-Flores, Alberto:
Univ Nacl Autonoma Mexico, Fac Med, Dept Bioquim, Mexico City 04510, DF, Mexico
del Arenal Mena, Irene Patricia:
Univ Nacl Autonoma Mexico, Fac Med, Dept Bioquim, Mexico City 04510, DF, Mexico
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