Laser tweezers show malaria invading red blood cells
Date: Aug-20-2014 One of the features of the malaria parasite that makes it difficult to study is the fact
it takes less than one minute for it to travel from one red blood cell to infect another, and it
quickly loses its infective ability within 2 or 3 minutes of leaving a blood cell. Now with
the help of a new device - laser optical tweezers - scientists find they can look in great detail
at how the parasite interacts with red blood cells during this short time interval.
Dr. Julian C. Rayner and colleagues of the Wellcome Trust Sanger Institute, located near
Cambridge in the UK, describe their findings in the Biophysical Journal.
Dr. Rayner, who runs a lab that is investigating the molecular details of the blood stages of
the malaria-causing parasite Plasmodium falciparum, says:
"Using laser tweezers to study red blood cell invasion gives us an unprecedented level of
control over the whole process and will help us to understand this critical process at a level of
detail that has not been possible before."
He and his colleagues hope their findings, which reveal some surprising facts about malaria
biology, will help the development of drugs and vaccines against a disease that infects millions
of people and causes over 600,000 deaths a year.
Laser optical tweezers exert extremely small forces using a highly focused laser beam. This
allows for precise control over the movement of individual cells, say the researchers.
In their study they describe how they used the laser tweezers to pick up individual parasites
as they emerged from red blood cells and deliver them to another red blood cell, showing that the
technique can be used in the detailed study of the invasion process.
The team was also able to use the laser tweezers to measure how strongly, and the means by
which, the parasites stick to red blood cells.
Parasite sticks to red blood cells by means of many weak interactions
They found the parasites are able to adhere to red blood cells by means of lots of weak
interactions, which could perhaps serve as targets for new drugs that sever or block these
interactions.
When the parasite has lost its ability to invade a red blood cell, it retains the ability to cause temporary dents in the membranes of red blood cells.
They also discovered that even when the parasite has lost its ability to invade a red blood
cell - at this stage in its life cycle it is called a merozoite - it retains the ability to stick
to red blood cells by means of the weak interactions and cause temporary dents in the membranes
of red blood cells.
In a further stage of the study, the researchers used the laser tweezers to study the effect
of three different drugs on the weak interactions.
They conclude that, taken together, the findings show "the power of optical tweezers
technologies in unraveling the blood-stage biology of malaria," at the level of individual
cells.
The team now plans to use the laser tweezers to find out which genes and proteins are involved
in each step of the invasion process.
"This will allow us to design better inhibitors or vaccines that block invasion by targeting
multiple steps at the same time," says Dr. Rayner.
Meanwhile, Medical News Today recently brought news of a study where scientists
discovered a possible way to trap
the malaria parasite in a prison of its own making. The discovery also identifies a protein
that offers a new drug target.
Written by Catharine Paddock PhD
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Courtesy: Medical News Today
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