Barcoding local - Contributions by course participants (5)

Another guest post from one of the course participants. This time Kelsey Hoffmann. masters student at Winona State Univeristy in Minnesota who is doing research on parasites.

DNA barcoding will be a very useful tool for the research that I am doing at Winona State University. I am currently trying to identify parasites that I have found in bobcats and river otters from Wisconsin. Unfortunately, during the collection process, many of the parasites get damaged making it extremely difficult to get an exact identification. With most cestode (tapeworm) species that have been collected from the bobcats the only way to identify them morphologically is to have an undamaged scolex.

The scolices of two different species of tapeworm: T. solium (A) and T. saginata (B). The only thing differentiating these two species of tapeworms is if hooks are present on the anterior end. Unfortunately, scolices are very fragile and hooks can come off during the collection processes making identification using morphology difficult and inaccurate. Image taken from here.

The scolex is considered the “head” of the tapeworm and is what attaches to the intestinal wall of its

definitive host. They are very small and incredibly difficult to find within the digested material from an animals gastrointestinal tract. If they are recovered, they are usually in very poor condition, making an accurate identification of its species virtually impossible. The identification process, and any other research planned, for the parasites found in the Wisconsin bobcats has been put on hold as samples have been sent to other institutions, like the University of Helsinki in Finland, for identification. Having to send out samples for identification not only puts a temporary stop to the furthering of the research it also cost money. The way these parasites are preserved also posses a problem for identification. Once removed from the intestine all parasites are put into vials containing 70% ETOH, this helps to halt any degradation but it also dehydrates the specimens making them hard to identify, morphologically, at a later date. This is where having the ability to do DNA barcoding here in the lab at Winona State would be a beneficial tool. 

Currently, river otters (Lontra canadensis) from Wisconsin are being examined at Winona State for gastrointestinal parasites. The most prevalent types of infections found in the river otters thus far are Echinostoma species, Acanthocephala species, and Nematode (roundworm) species. Within each of the parasite groups the specimens that have been collected range in different size, color, and morphological features. For example, within the Echinostoma species there have been at least two visually different looking specimens collected. 

The anterior oral suckers of Echinostoma
 collected from Wisconsin river otter intestines

The two specimens of Echinostoma spp. collected have different anterior oral suckers and were also much different in size. These different morphological features seem to suggest that these two specimens are two different species of Echinostoma, however, it is possible that they could also be the same species but are at two different stages of development. Without having access to an expert taxonomist it is difficult to get an exact identification. Being able to preform the steps to get the DNA barcodes at Winona State University for any of the parasite specimens collected would help to answer these types of questions in an accurate at timely manner.

Having DNA barcoding in the arsenal of tools that could be used to identify very small, and at times microscopic, parasites would be beneficial to this research. I think it would be fairly simple to start doing DNA barcoding at Winona State as many of the things we need to perform it we already have available.