New Insights on Apicomplexa Biology

Although viruses and bacteria currently get the lion’s share of research money and media attention, parasitic diseases kill millions of people each year.  Why are they overlooked so frequently?  They largely don’t affect Americans.  It’s the sad, but true, world of science and journalism and research funding.

However, in the most recent edition of PLoS Pathogens, researchers from the University of Georgia and the University of Montana (among others) released a ground-breaking study on Apicomplexa biology.  Hadn’t heard of Apicomplexa?  Neither had I.  But they are a phylum that consists of many of the parasites that have plauged humans for millennia, such as Toxoplasma gondii, Cryptosporidia, and Plasmodium sp., the latter of which cause malaria in hundreds of millions of people each year.  Studying these little critters has been difficult first because, being eukaryotes, they have substantially more genes than bacteria or viruses.  Second of all, drug development has been hindered because, again, they’re eukaryotes.  Things that kill them are much more likely to kill or harm us.

When you add all of these factors to the historical deficits in funding towards tropical disease (read as: diseases that don’t affect Americans and therefore effectively don’t exist), it meant that little progress was being made towards finding new cures for malaria and like diseases.

Enter the current study on Aplicomplexa.

What these scientists did was take a first step in developing a more firm understanding of parasite biology.  Many of these genomes have been sequenced.  And, like with the Human Genome Project, it’s a fantastic first step.  But only a first step.  Information isn’t all that useful until you can, I don’t know, actually use it.  The biologists involved with this study created a high-throughput genetic screening for heat-sensitive Toxoplasma gondii mutants.

Which means precisely nothing, until you understand that “high-throughput genetic screening” really means an easy way to look at a lot of different genetic sequences really really quickly, and that heat sensitivity is really just a way for scientists to identify mutations that might be involved with cell replication and development.  Using a technique called “forward genetics,” the researchers first generated thousands of mutant Toxoplasma cells, each with a potentially different mutation affecting their growth and development.  Then, using the high-throughput screening method, these genes were identified and paired with the mutation.

This isn’t a cure-all by any means.  Drug development is still years, if not decades, down the road.  But a basic understanding of the Toxoplasma cell machinery has been greatly improved, and with this step, drug development can move forward.

You can find the full text of the article here: Forward Genetic Analysis on the Apicomplexan Cell Division Cycle in Toxoplasma Gondii.