West Texas – field venom extraction

Mike Hogan put together a short video of how we process venomous snakes in the field. In the video, venom extraction is being performed by Mark Margres, with Micaiah Ward and Alyssa Bigelow assisting. Both animals being processed are Crotalus ornatus. The goal is to get venom and blood samples from each individual while minimizing handling and stress on the animal. The blood samples are used for genetics, and the venom samples are analyzed proteomically to compare venom compositions between species or population (such as we did here).

West Texas 2016

Members of the Rokyta Lab and Dr. Lisle Gibbs’ lab traveled out to west Texas at the end of June after the Evolution Conference in Austin for several days of fieldwork. We did extremely well with venomous species. We saw numerous western diamondback rattlesnakes (Crotalus atrox), prairie rattlesnakes (Crotalus viridis), Mojave rattlesnakes (Crotalus scutulatus), black-tail rattlesnakes (Crotalus ornatus), and a single rock rattlesnake (Crotalus lepidus).  We’ll be posting more pictures and videos from this trip soon.

From left to right: William Booker (Lemmon lab), Mark Margres, Micaiah Ward, Alyssa Bigelow, and Mike Hogan. 

Mike Hogan got some good video of a western diamondback rattlesnake:

Centipede venom extraction

We started trying to work with centipede venoms in 2014, but we struggled for months to perfect the process of venom extraction. We were used to snakes, with their huge venom yields and long-established procedures for extracting venom. And snakes, of course, have no legs, which actually makes them fairly easy to move around and restrain. Suddenly, we had legs everywhere. Fast, grippy legs. Venom yields were often so low that the liquid would evaporate faster than we could convince ourselves that there was actually something there.

Fortunately, Dr. Eivind Undheim was incredibly generous with his advice on how to extract venom from centipedes, and we were able to develop a procedure that works consistently. The animals are first anesthetized by exposure to CO2 for about two minutes, which keeps them under for three to five minutes. We then restrain them using velcro strips while we apply electrostimulation to the bases of the forcipules. The forcipules are the modified first pair of legs that house the venom glands. We use a commercially available TENS unit to apply low voltage/high frequency elctrostimulation to induce muscle contraction and expel the venom. We use a small spatula to catch the venom and to prevent its mixing with saliva. The video below shows the process after the animal has been anesthetized.

Evolution 2016

The Rokyta Lab had a strong showing at this year’s Evolution Conference in Austin, TX. Mark Margres and Alyssa Bigelow gave talks on snake-venom evolution, Micaiah Ward gave a talk on scorpion venom variation, and Andrew Sackman and Carl Whittington gave talks on bacteriophage experimental evolution. A video of Mark’s talk is below.