Super Resolution Microscopy made it possible that Australian scientists have for the first time caught malaria parasites in the act of invading red blood cells. The researchers, from the Walter and Eliza Hall Institute and the University of Technology, Sydney (UTS), achieved this long-held aim using a combination of electron, light and super resolution microscopy, a technology platform new to Australia.
The detailed look at what occurs as the parasite burrows through the walls of red blood cells provides new insights into the molecular and cellular events that drive cell invasion and may pave the way for developing new treatments for malaria. Institute researchers Dr Jake Baum, Mr David Riglar, Dr Dave Richard and colleagues from the institute's Infection and Immunity division led the research with colleagues from the i3 institute at UTS.
Dr Baum said the real breakthrough for the research team had been the ability to capture high-resolution images of the parasite at each and every stage of invasion, and to do so reliably and repeatedly. Their findings are published in the journal Cell Host & Microbe.
"It is the first time we've been able to actually visualise this process in all its molecular glory, combining new advances developed at the institute for isolating viable parasites with innovative imaging technologies," Dr Baum said. "Super resolution microscopy has opened up a new realm of understanding into how malaria parasites actually invade the human red blood cell. Whilst we have observed this miniature parasite drive its way into the cell before, the beauty of the new imaging technology is that it provides a quantum leap in the amount of detail we can see, revealing key molecular and cellular events required for each stage of the invasion process."
The imaging technology, called OMX 3D SIM super resolution microscopy, is a new 3D tool that captures cellular processes unfolding at nanometer scales. The team worked closely with Associate Professor Cynthia Whitchurch and Dr Lynne Turnbull from the i3 institute at UTS to capture these images. Dr Baum said the methodology would be integral to the development of new malaria drugs and vaccines. "If, for example, you wanted to test a particular drug or vaccine, or investigate how a particular human antibody works to protect you from malaria, this imaging approach now gives us a window to see the actual effects that each reagent or antibody has on the precise steps of invasion," he said.
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Further he said that one of the most interesting discoveries the imaging approach revealed was that once the parasite has attached to the red blood cell and formed a tight bond with the cell, a master switch for invasion is initiated and invasion will continue unabated without any further checkpoints.
Malaria is caused by the Plasmodium parasite, which is transmitted by the bite of infected mosquitoes. Each year more than 400 million people contract malaria, and as many as a million, mostly children, die.
Riglar D.T. et al.: Super-Resolution Dissection of Coordinated Events during Malaria Parasite Invasion of the Human Erythrocyte. Cell Host & Microbe, Volume 9, Issue 1, 9-20, 20 January 2011
Teaser image: Dr Jake Baum and Mr David Riglar, from the institute's Infection & Immunity division, have for the first time captured the malaria parasite in the act of invading red blood cells. Source: Walter and Eliza Hall Institute
Webcast: A 3D reconstruction showing a Plasmodium falciparum parasite mid invasion. The red cell is labelled in red and the parasite is labelled in green, using conventional fluorescence microscopy. Source: Walter and Eliza Hall Institute
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