Seminarium z fizyki biologicznej i bioinformatyki

link do spotkania: https://zoom.us/j/91976153012?pwd=azNiMWE4UnhPN3lRQlY2UHZHOXVkQT09

Malaria parasites infect red blood cells and digest host hemoglobin. The released free heme is highly cytotoxic, promoting the formation of reactive oxygen species. To mitigate it, the parasite sequesters free heme into inert hemozoin nanocrystals inside a specialized digestive compartment called the food vacuole. The biocrystallization of heme is thus a critical parasite survival strategy and a major antimalarial drug target. While the static properties of hemozoin are well-known, the mechanism behind its continuous erratic motion has remained unexplored.Through quantitative in-cell image analysis, we show that this motionrequires an intact food vacuole, but not the parasite itself. Furthermore, using single-particle tracking and Brownian dynamicssimulations, we demonstrate that the motion of crystals is inconsistentwith a model of passive Brownian motion under confinement, pointinginstead to a local driving mechanism within the vacuole. We identifyhydrogen peroxide as a potential source of this driving, as it stimulates the motion of isolated crystals in solution, while its suppression by culturing parasites under low-oxygen conditions slows hemozoin dynamics in vivo.Ultimately, our work reframes hemozoin crystals - long viewed as mereinert detoxification products—-as catalytically active, peroxide-poweredself-propelled nanoparticles. We propose that this propulsion mechanismconsumes reactive oxygen species while simultaneously preventingnanocrystal aggregation to optimize their active surface area.