An amazing meeting full of Xenopus people!

It was my first time to experience the International Xenopus Conference, but I left wishing that I had been to many more. The conference abstract book is available online here, and the talks were just as diverse as the people giving them. Walking around the posters, and talking to the speakers, I quickly understood that everyone shared a passion for working with Xenopus frogs (both X. laevis and X. tropicalis), at the same time as acknowledging that this was a little unusual. 

I conducted my PhD in a department where Xenopus was used as a model organism to study neural biology. Thus I was acquainted with the other world of Xenopus users. However, I was completely unaware of the more recent scope of the work that is currently being conducted with this species. It is staggering the breadth of work being done, especially the way in which Xenopus is now being used as a model for single gene mutations in children. The speed of replicating the gene mutation suffered by a newborn child in a tadpole can really help clinicians work on finding better treatments. 

The meeting was held in a Hyatt-Regency Hotel, alongside large numbers of golfers and other holiday revelers. Certainly, I'd guess that most of these folks were unaware of the large number of frog lovers meeting in the ballroom.

Many thanks go out to the conference organizers who went above and beyond to help me attend. It was a truly great experience, and I look forward to the next one!

Abstract
Home and away: the core gut microbiome of Xenopus laevis is modified by its environment

Authors: Measey, J., Ersin, M., Guille, M., Almojil, D., Araspin, L., Wagener, C., Boissinot, S., Watts, J.,
Robson, S.
Presenting Author Affiliation: Centre for Invasion Biology, Institute of Biodiversity, Yunnan University, China & Centre for Invasion Biology, Stellenbosch University, Stellenbosch, South Africa

Abstract: The vertebrate gut microbiome is a community largely composed of bacterial, fungal and viral components, whose molecular component equal that of the host. The influence of the microbiome is known to be significant both on an individual basis, and also on population scales in a wide range of host organisms. The gut microbiome is known to be involved with key attributes of animal health, including assimilation of nutrients, immuno-defensive functions and host behavior. In this study, we used bacterial 16S rRNA amplicon-based sequencing for metataxonomic classification of the gut microbiome of individuals from eight populations of Xenopus laevis. These populations were selected to represent an altitudinal gradient in of the host species (0 to 3000 m asl). From the 16S rRNA community profiles, we determine the components of the core microbiome of X. laevis, and ask whether deviations from the core are associated with the environmental context in which they live. In addition, we sampled four European invasive populations and a laboratory population from the European Xenopus Resource Centre (EXRC) in the UK, to determine what aspects of the core microbiome are retained by non-native populations. This represents the first time that the microbiome of X. laevis has been assessed across such diverse conditions,
and provides data that will help understand the role played by the environment and inform monitoring of health within this model organism.

Visiting the Tropical Aquaculture Lab in Ruskin FL

The news that there is an invasive population of Xenopus tropicalis in Florida is now well established. For a short time, workers at the Tropical Aquaculture Lab thought that they had a population of very small Xenopus laevis (Hill et al. 2017), but once the identification was rectified the remarkable invasion was a reality and quickly spreading across the region (Goodman et al. 2021). I put some special time aside in my schedule to visit the Katie Everett, Quenton Tuckett and Jeff Hill at the Tropical Aquaculture Lab.

Excitingly, Katie took me to the field to collect some X. tropicalis  from one of the ponds in the area. Although we set traps in a lot of ponds, only one of them turned up any of the frogs, but we did capture over 50!

It was a great to see this invasive species together with so many other herps in Florida. Katie and assistant Myles were very helpful when it came to emptying all of the many traps that we saturated the pond with. 

Now that I've seen an invasive population of these animals, I'm really looking forward to seeing them in their native range. I feel sure that they occur in very similar habitats in their native Gabon. Stay tuned for reports on our visit to Gabon!

Further Reading

Hill, J.E., Lawson, K.M. and Tuckett, Q.M., 2017. First record of a reproducing population of the African clawed frog Xenopus laevis Daudin, 1802 in Florida (USA). BioInvasions Record, 6(1).

Goodman, C.M., Jongsma, G.F., Hill, J.E., Stanley, E.L., Tuckett, Q.M., Blackburn, D.C. and Romagosa, C.M., 2021. A case of mistaken identity: Genetic and anatomical evidence reveals the cryptic invasion of Xenopus tropicalis in central Florida. Journal of Herpetology, 55(1), pp.62-69.

The Amphibian Foundation is home to amazing people

One of the amazing aspects to my visit to North America has been meeting with so many people that share similar interests. A particular privilege today is becoming part of the Amphibian Foundation, based in a fantastic facility in Atlanta GA. The founder of AF, Mark Mandica, is a long-term friend who I first met while he was doing his MSc at Miami University back in 2003. Mark and I have kept in touch ever since those days, and this has seen both of us move around quite a bit. Mark, and partner Crystal, has done great things at the Amphibian Foundation and are constantly building on their success.

I was greatly honoured by their request for me to become part of their affiliated faculty, to which I have happily accepted today.

The Amphibian Foundation has an amazing outreach programme with hundreds of participants from the local area learning about respect for local amphibians and reptiles as well as their global needs. When one a five minute break from their class time activities, they all rushed out to the parking lot where they immediately started flipping rocks looking for toads. These kids are very serious about having a lot of fun in the field with amphibians!

The Amphibian Foundation also has some serious amphibian conservation ambitions. For example, their plans to help the Frosted Flatwoods Salamander, Ambystoma cingulatum, include both rehabilitating habitat and captive breeding for a headstarting programme (see here).   

I'm proud to be affiliated with this team of amazing herpetologists.

Contact me at the Amphibian Foundation: john@amphibianfoundation.org  

Catching Xenopus in Baja California, Mexico

With the invasive population of African clawed frogs being in so many drainages in San Diego, it was long expected that they would cross the border into Tijuana, the city at the border between USA and Mexico. But it wasn't until 2014 that Anny Peralta-García and colleagues reported that these frogs had not only crossed the border, but had travelled around 20 km South along the coast and appeared to have moved up the drainage inland.

The Tijuana River does not look hospitable to African clawed frogs, but when the flow is slow like this, they can use it as a corridor to expand their invasion.

Reports from Anny and colleagues with those posted on iNaturalist now indicate that the invasion has moved ~40 km south of the border. I was very lucky to be able to work with Anny and Jorge and make a quick visit to Baja-California. Both Anny and Jorge were out of town, but I met up with Diego Maldonado who very kindly picked me up in Tijuana and drove me to the two southernmost sites to place traps.

Diego at one of the sites near Puerto Nuevo.

Although we were unlucky at the inland site, we found large numbers of animals near Puerto Nuevo. Here you see Diego pulling in one of the traps.

Moreover, we could see many animals in the water. I've ringed a couple in the picture below. How many more can you see?

 

Thanks to Anny, Jorge and Diego for making my trip to Mexico not only possible but also successful. It was great to learn about Baja-California and see some of the beautiful areas that Xenopus has invaded.

Literature

Anny Peralta-García, Jorge H. Valdez-Villavicencio, and Patricia Galina-Tessaro "African clawed frog (Xenopus laevis) in Baja California: a confirmed population and possible ongoing invasion in Mexican watersheds," The Southwestern Naturalist 59(3), 431-434

Xenopus from LA with stars in their eyes

Among all the glitz and glam of life in LA, there is an invasion of African clawed frogs that has made its way into many of the waterways and drainages in the area. I was very lucky to meet up with Greg Pauly from the LA County Museum. Greg has his own passion for Xenopus with a citizen science project to determine how diverse their predators are (see here). Greg is a fountain of knowledge about all things wild and urban in LA, so of course he was the perfect guide for collecting clawed frogs. Greg knew of many sites to catch frogs in LA, and was happy to get his seine net out and hit some of LA's most salubrious spots to pull some specimens out of the water. 

Greg took us to two sites in the LA area. The first (pictured above) was inside a park where Greg had seined animals before. We were joined for the day by Estella and Taylor from the LA County Museum who were both great frog wranglers once we got the seine net in.

We collected a bunch of tadpoles and ~10 adults from this small pond connected to the road sewer system. The water was really fowl and black. The frogs and tadpoles seemed to love it!

 

After we got over the stench of our equipment at the first site, we were quite unprepared to find something much much worse. The second site was really bad. Above you can see how it looked after we had finished seining out the many plastic bags, condoms, masks and other unidentified matter from this road sewer. Note the grey-brown colour of the water - for those not in the know, this is the colour of raw sewage. Once again, we caught a bunch of tadpoles and around 20 adults from this site. They appeared not to share our concerns about the water they lived in and instead appeared to be thriving there, and it was even possible to see the stars in their eyes...

Thanks so much to Greg, Estella and Taylor for making this trip to LA so successful!