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| Human World on Jan 20, 2011

Scientists catch malaria in the act of invading cells

Hundreds of millions of people contract malaria every year. New high resolution images show the mosquito-borne parasite in the act of breaking into a red blood cell.

Australian scientists have captured the malaria parasite in the act of invading a red blood cell, using a powerful new microscopic technique that can take images on the nanometer scale. The high-resolution images show the parasite at each step of its invasion, a view that researchers hope will help spur on a breakthrough in combating the deadly disease.

Credit: David Riglar and Jacob Baum (Walter and Eliza Hall Institute) with support from Cynthia Whitchurch and Lynne Turnbull (University of Technology, Sydney).

When a mosquito carrying the malaria parasite bites a human, the parasite hides out in the liver until it begins to attack and multiply in red blood cells. It literally burrows into the cell. Looking at the above image, you can see the parasite’s biggest tool in green. It’s called a tight junction, and the parasite, in blue, brings it along to create a “window” into the cell. The red object is a vacuole, a structure in the cell’s membrane. In the final shot, you can see the parasite has sealed itself inside the vacuole, within the red blood cell. Below, you’ll see another view. The red blood cell is in gray.

Image credit: David Riglar and Jacob Baum (Walter and Eliza Hall Institute) with support from Cynthia Whitchurch and Lynne Turnbull (University of Technology, Sydney).

The research and images were published in the journal Cell Host & Microbe in January 2011. Dr. Jake Baum, who led the research at the Walter and Eliza Hall Institute of Medical Research, described what happens to Australia’s ABC News:

It’s very graceful actually the way the parasite sidles up next to a red blood cell, turns around, puts its pointy end, if you can imagine an egg, pushes that against the red cell surface and it drives itself in with very little fuss.

Scientists have observed this process before, but this is the first time they’ve been able to take pictures of the event. Baum told ABC News that the technology is an important tool to understand how new anti-malarial drugs or potential vaccines act against the parasite.

If we can actually either add an antibody say from a vaccine trial or a new drug and see what happens to the parasite as it invades we can actually understand how the inhibitory compound or antibody is actually working.

The technology is called super resolution microscopy, and it takes photos at nanometer scales. The parasite itself is only one micron, or one millionth of a meter, in diameter.

Malaria has been targeted as one of the world’s top health issues. More than 400 million people contract malaria each year. The disease kills as many as a million people each year, most of them children, according to the World Health Organization. But scientists believe that research is bringing them close to a breakthrough. Catching the malaria parasite in the act is a good step in that direction.

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