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Tuesday, May 15, 2012

“Black flies may have a purpose after all”



That was the title of a press release I just read. I’m sure the black flies will be delighted to hear this. All this time, they’ve been moping about in existential despair. What, did you think I didn’t write this blog to amuse myself? Okay, obviously, the paper is about how black flies might be of some use to us. So let’s get to it.

Like most biting insects, black flies (Simulium vittatum) secrete products in their saliva to prevent blood from clotting while they’re taking their meal. Hitoshi Tsujimoto and his colleagues from the University of Georgia, the Academy of Sciences of the Czech Republic and from the National Institutes of Health have identified just such a protein in black fly saliva, dubbed ‘Simukunin’. It is expressed only in females but not males, who feed on nectar rather than blood.

Blood clotting in mammals is a complicated business involving a cascade of products. As each protein is cleaved, it becomes the active enzyme capable of cleaving the next in line. Ultimately, the final protein is activated and a fibrin clot is produced. Clotting inhibitors can disrupt the pathway by binding to certain factors and preventing them from cleaving and activating other factors.  In this way, coagulation is circumvented.

Sure enough, Simukunin binds to clotting factors and interferes with coagulation. Even more intriguing, Simukunin also appears to play a role in preventing inflammation. It binds even more strongly to factors involved in the inflammatory response.

Because the authors were able to synthesize functional Simukunin, it could prove to be a useful anti-coagulant and possibly anti-inflammatory drug. Black flies can rejoice that they now have meaning in their lives.

By the way, if you want to study black flies you should definitely go to the University of Georgia.  They have the only contained black fly colony in the world. Luckily for the residents of Georgia, their flies are not vectors for disease.

As Don Champagne of the University of Georgia emphatically states:
They are not being infected with the parasite that causes river blindness; and there is no risk to the public.