Many infectious pathogens, like those that cause Toxoplasmosis or Leishmaniases, have a complex life cycle alternating between free-living creature and cell-enclosed parasite. A thorough analysis of the proteins that help these organisms undergo this lifestyle change would be tremendously useful for drug or vaccine development; however, it's extremely difficult to separate the parasites from their host cell for detailed study.
As reported in the September Molecular & Cellular Proteomics, Toni Aebischer and colleagues worked around this problem by designing special fluorescent Leishmania mexicana (one of the many Leishmaniases parasites). They then passed infected cells through a machine that can separate cell components based on how much they glow. Using this approach, the researchers separated the Leishmania parasites with only about 2% contamination, far better than current methods.
They then successfully identified 509 proteins in the parasites, 34 of which were more prominent in parasites than free -living Leishmania. The results yielded many characteristics of these organisms, such as a high presence of fatty acid degrading enzymes, which highlights adaptation to intracellularly available energy sources. The identified proteins should provide a good data set for continued selection of drug targets, and the success of this method should make it a good resource for other cellular parasites like malaria.
