September 21, 2015
Ever since we wrote how probiotics are helping save endangered Chinese Panda Bears and fish, we’ve stumbled upon even more interesting research on how probiotics may help the animal kingdom – this time it’s about how probiotics may help save frogs from extinction!
Why do we want to save frogs? Whether they are endangered or threatened, these slippery, slimy amphibians need to be protected just as much as the pandas and fish. They’re definitely not as cute as pandas, nor are they a major food source, at least not here in the U.S. like trout or salmon, but they’re very important to the ecosystem. They are beneficial to us humans because they eat pests and other insects that cause malaria, and they’re prey to a vast range of creatures, from reptiles to birds – and other frogs. If frogs become extinct, it won’t be too long before their predators will follow.
Surprisingly, they are known as an indicator species, meaning that their health is thought to be indicative of the biosphere as a whole. If there are lots of frogs and other amphibians in a habitat, it means the ecosystem is healthy, but once they begin to disappear, it is a sign of pollution and disease. This should serve as an alarm-call to humans that something is drastically wrong in the environment.
Frogs have existed on this planet for several million years, and even though they are constantly under threat, they have managed to survive difficult environmental conditions. Today, many amphibians are on the verge of extinction for one reason or another; but a particularly deadly fungus called Batrachochytrium dendrobatidis, or Bd for short, has wiped out close to 200 amphibians and it’s working its way to killing the rest. One of its victims is a bright yellow and black frog called he Panamanian Golden Frog.
Conservationists have been successful at breeding this frog in captivity, but it’s already extinct in the wild largely because of the deadly clutches of Bd. Captive frogs aren’t likely to survive if they were released back into their natural habitat. Not unless there is a solution.
Perhaps that solution may be in the form of probiotics. In 2006, a team of researchers discovered that there are a few other amphibians (salamanders and another type of frog) that naturally carry a bacterium on their skin, called Janthinobacterium lividum. J. lividum acts like a coat of armor preventing Bd from growing. They wondered if they bathed the laboratory-bred golden frogs with J. lividum, would they too become resistant to the fungus. Could this probiotic bacteria act as an anti-fungal so they could release these frogs back into their natural environment?
Unfortunately, the anti-Bd probiotic didn’t persist on the frogs skin. According to the article, they theorized that maybe because the frogs were from Panama and carried their own unique probiotic microbes, and the bacterium was from California, that it wasn’t a good fit. New samples of other bacteria were collected that were more closely related to the golden frog, and while some of these also stopped Bd from growing in lab tests, the treated frogs survived no longer than untreated ones. The new microbes didn’t seem to make any difference to the frogs existing microbes either. Despite this initially disappointing finding, what they did discover was that five of the frogs bathed in J. lividum managed to clear the fungus on their own, and that was unheard of in golden frogs! Closely studying these frogs, the team discovered they were different than the ones that died. The difference seemed to be in the groups of bacteria found on their skin and the chemicals those bacteria produced. Would these new groups of microbes protect against Bd, or do they resist the fungus on specific skin microbes? If they do protect against Bd, would the frogs survive in their natural habitat?
Questions remain and finding the answers isn’t easy. There are environmental considerations, and what may work on one species may not work on another. Like human probiotics, there does not appear to be a one-size-fits-all solution, and we need to keep pushing the boundaries of bacterial science to find the answer. We are reminded that many, perhaps every single species, depend on probiotic bacteria for their survival. At the same time, we must question where did this deadly fungus come from? Is there something going on in our environment on a broader spectrum that is causing an increased fungal load? Did these frogs used to have probiotic bacteria present that protected them? Have they have lost a probiotic bacterial layer over time? Or is the fungus getting stronger? Time and hard scientific work may reveal some of these answers, and we look forward to learning more.
If you want to learn more or keep up to date with the research on frogs you can follow the study here: http://rspb.royalsocietypublishing.org/content/282/1805/20142881
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