Helminth mitochondrial respiratory chain

The helminth mitochondrial respiratory chain is a specialized metabolic system essential for the survival of parasitic flatworms, including tapeworms (cestodes). Unlike their mammalian hosts, many adult helminths inhabit anaerobic or microaerobic environments within the host's gastrointestinal tract and rely on a unique anaerobic respiratory pathway known as the NADH-fumarate reductase system (Kita et al., 2012). This system utilizes rhodoquinone as an electron carrier to reduce fumarate to succinate, a process catalyzed by a parasite-specific complex II (fumarate reductase) that differs significantly from the succinate dehydrogenase found in humans (Omura et al., 2001). Drugs such as niclosamide target this machinery by acting as uncouplers of oxidative phosphorylation, which dissipates the mitochondrial proton gradient and halts ATP production (Winn et al., 2021). Other anthelmintics, like certain benzimidazoles and specialized inhibitors like nafuredin, directly interfere with the enzymes of this respiratory chain (Kita et al., 2012). Because of these distinct biochemical adaptations, the tapeworm mitochondrial machinery represents a highly effective target for selective chemotherapy against helminthic infections. Disruption of this machinery leads to rapid ATP depletion, loss of motor function, and eventual death of the parasite.

Other names

Tapeworm mitochondrial functional machineryNADH-fumarate reductase systemCestode mitochondrial respiratory chainHelminth anaerobic respiratory chainFumarate reductase system

Uncoupling of oxidative phosphorylation and inhibition of the NADH-fumarate reductase system, leading to the dissipation of the mitochondrial membrane potential and depletion of cellular ATP (Kita et al., 2012; Winn et al., 2021).