Cryptosporidium parvum is a gastrointestinal parasite that can cause moderate to severe diarrhea in children and adults, and deadly opportunistic infection in AIDS patients. Because C. parvum is resistant to chlorine disinfectant treatment, it frequently causes water-borne outbreaks around the world. A study published on November 12th in PLOS Pathogens provides a detailed analysis of a C. parvum protein that is central to glycolysis – the only pathway by which the parasite can generate energy – and identifies it as a potential drug target.
Guan Zhu and colleagues, from Texas A&M University in College Station, USA, study the parasite’s metabolism during its complicated life-cycle. C. parvum exists both in free stages (where parasites are in the environment or in the host’s digestive tract) and intracellular stages following host cell invasion, during which the parasite occupies a specialized compartment – the parasitophorous vacuole – which is delineated by a host-cell derived border called the parasitophorous vacuole membrane (PVM).
CpLDH on the parasitophorous vacuole membrane
Lactate dehydrogenase (LDH) is typically a cytosolic protein, which is true in the extracellular stages of the apicomplexan parasite Cryptosporidum parvum (oocysts and sporozoites). However, LDH becomes localized to the parasitophorous vacuole membrane (PVM) during the parasite intracellular development (LDH in red and nuclei in blue). The top panel show oocysts stained only for oocyst walls (green) and nuclei (blue)