A New Review of Chemicals Produced by the Toad Family, Bufonidae
As human diseases become alarmingly antibiotic resistant, identification of new pharmaceuticals is critical. The cane toad and other members of the Bufonidae family produce substances widely used in traditional folk medicine, but endangered family members, like Panama’s golden frog, Atelopus zeteki, may disappear before revealing their secrets. Smithsonian scientists and colleagues catalog the known chemicals produced by this amphibian family in the Journal of Ethnopharmacology highlighting this largely-unexplored potential for discovery.
“We’re slowly learning to breed members of this amphibian family decimated by the chytrid fungal disease,” said Roberto Ibañez, Panamanian staff scientist at the Smithsonian Tropical Research Institute (STRI) and in-country director of the Panama Amphibian Conservation and Rescue (PARC) project. “That’s buying us time to understand what kind of chemicals they produce, but it’s likely that animals in their natural habitats produce an even wider range of compounds.”
15 of 47 frog and toad species used in traditional medicine belong to the family Bufonidae. For millennia, secretions from their skin and from glands near their ears called parotid glands, as well as from their bones and muscle tissues have been used as remedies for infections, bites, cancer, heart disorders, hemorrhages, allergies, inflammation, pain and even AIDS.
Toxins of two common Asian toad species, Bufo gargarizans and Duttaphrynus melanostictus, produce the anticancer remedies known as Chan Su and Senso in China and Japan, respectively. Another preparation used to treat cancer and hepatitis, Huachansu or Cinobufacini, is regulated by the Chinese State Food and Drug Administration. In Brazil, the inner organs of the toad, Rhinella schneideri, are applied to horses to treat the parasite Habronema muscae. In Spain, extract from the toad Bufo bufo is used to treat hoof rot in livestock. In China, North and South Korea, ranchers use the meat of Bufo gargarizans to treat rinderpest.
Only a small proportion of the more than 580 species in the Bufonidae family have been screened by scientists. “In Panama, not only do we have access to an amazing diversity of amphibian species,” said Marcelino Gutiérrez, investigator at the Center for Biodiversity and Drug Discovery at Panama’s state research institute, Instituto de Investigaciones Cientificas y Servicios de Alta Tecnologia (INDICASAT), “we’re developing new mass spectrometry and nuclear magnetic resonance spectroscopy techniques to make it easier and cheaper to elucidate the chemical structures of the alkaloids, steroids, peptides and proteins produced by these animals. We work closely with herpetologists so as not to further threaten populations of these species in the wild.” Their efforts to catalog chemicals produced by the Bufonidae included researchers from the University of Panama, Vanderbilt University, in Tennessee, U.S.A. and Acharya Nagarjuna University in Guntur, India.
Most of the chemicals produced by frogs and toads protect them against predators. Atelopus varius contains tetrodototoxin. Chiriquitoxin is found in Atelopus limosus, one of the first species that researches succeeded in breeding in captivity as well as in Atelopus glyphus and Atelopus chiriquiensis. An atelopidtoxin (zetekitoxin) from the Panamanian golden frog, Atelopus zeteki, appears to consist of two toxins. Toxins from a single frog skin can kill 130-1000 mice.
The golden frog, A. zeteki, Panama’s national frog, is the only species of the genus Atelopus that secretes zetekitoxins. Threatened by the chytrid fungal disease that infects the skin and causes heart attacks, with collection for the exotic pet trade and by habitat destruction, if golden frogs were to disappear, they would take this potentially valuable chemical with them.
More than 30 percent of amphibians in the world are in decline. Racing to stay ahead of the wave of disease spreading across Central America, Panama is leading the way in conservation efforts. The Smithsonian’s Panama Amphibian Rescue and Conservation project (PARC) identified several Atelopus species in danger of extinction, and are learning how to create the conditions needed to breed them in captivity. Not only do animal caretakers at their facilities in Gamboa and El Valle, Panama experiment to discover what the frogs eat, they also recreate the proper environment the entire frog life-cycle: egg laying, egg hatching and tadpole survival, to successfully breed Atelopus. Each species has unique requirements, making it an expensive challenge to create this Noah’s ark for amphibians.
The chemical building blocks amphibians use to create toxic compounds come from sources including their diet, skin glands or symbiotic microorganisms. Toads in the genus Melanophryniscus sequester lipophilic alkaloids from their complex diet consisting of mites and ants. Researchers found that toxins found in a wild-caught species of Atelopus could not be isolated from frogs raised in captivity: another reason to conserve frog habitat and to begin to explore the possibility of releasing frogs bred in captivity back into the wild.
Learn more about amphibians by visiting the PARC blog and the Panama’s Fabulous Frogs exhibit at the Smithsonian’s Culebra Point Nature Center in Panama.
The Smithsonian Tropical Research Institute, headquartered in Panama City, Panama, is a part of the Smithsonian Institution. The Institute furthers the understanding of tropical nature and its importance to human welfare, trains students to conduct research in the tropics and promotes conservation by increasing public awareness of the beauty and importance of tropical ecosystems. Website. Promo video.
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Rodriguez, Candelario, Rollins-Smith, Louise, Ibanez, Roberto, Durant-Archibold, Armando, Gutiérrez, Marcelino. 2016. Toxins and pharmacologically active compounds from species of the family Bufonidae (Amphibia, Anura). Journal of Ethnopharmacology, doi:10.1016/j.jep.2016.12.021
EL VALLE DE ANTON
SATURDAY, AUGUST 13
FAMILY DAY #RANATICOS
Paseo El Valle, El Valle de Anton
11:00 AM – 3:00 PM
Activities: Games for children, exhibition of frogs, food and drinks, and the Golden Frog mascot.
SUNDAY, AUGUST 14
La Dorada Race
6:00 to 11:00 a.m.
Walk or run 5 to 15km to save a national treasure.
main streat of El Valle
SUNDAY, AUGUST 21
Amphibian Rescue and Conservation Project
1:00 – 4:00 PM
Activities: Open house to visit the amphibian Ark and meet the scientists.
18 -19 AUGUST
Atlapa Convention Center
9:00 a.m. to 9:00 PM
Activities: exhibition of science and live frogs, games, dynamic, book sales and more.
SATURDAY, AUGUST 20
FAMILY DAY #RANATICOS
Punta Culebra Nature Center,
Calzada de Amador, Panama
11:00 AM – 4:00 PM
Activities: Meet experts frogs, Restaurant Rana, face painting, many games, food and drinks.
Please remember that up until golden frog day, all donations to the amphibian rescue project will be generously matched by Golden Frog CLICK HERE TO DONATE
Amphibians are dying all over the world due to chytridiomycosis. This disease, caused by Batrachochytrium dendrobatidis (Bd), is responsible for dramatic amphibian declines and extinctions in the Neotropics, including Panamanian tropical forests.
We are a research team that is part of an NSF project investigating microbial diversity on frog skin in Panama. This team includes three principal investigators (Lisa Belden, Reid Harris and Kevin Minbiole), three postdoctoral fellows (Eria Rebollar, Myra Hughey and Tom Umile) and several graduate and undergraduate students from James Madison University, Virginia Tech, Villanova University and the Smithsonian Tropical Research Institute. We are interested in understanding how microbial communities from amphibian skin might contribute to the survival of amphibian species that have persisted in the wild despite the presence of Bd. Since 2012, we have collected samples from multiple sites in lowland tropical forests to describe the factors that shape skin microbial communities in tropical amphibians, including the presence of the pathogen Bd.
We recently published a study on the skin microbiota of five species of tropical amphibians from one of the few sites in Panamá where amphibians have not been infected with Bd, called Serranía del Sapo, in the Darién Province. In the summer of 2012, Myra Hughey, Roberto Ibáñez and Daniel Medina collected skin swab samples from this lowland site of highly susceptible and less-susceptible species, including two highly threatened species: Atelopus certus and Strabomantis bufoniformis. When we analyzed the bacterial species present on the skin of these five amphibian species we found that amphibians had a unique microbiota on the skin that was very distinct from the bacterial communities in the environment. These symbiotic bacteria were not only different from the environment, but were also different among the amphibian species. Interestingly we found that the three less Bd-susceptible species that we studied (Craugastor fitzingeri, Espadarana prosoblepon and Colosthetus panamansis) had a common set of bacteria that was not present on the two highly susceptible species (A. certus and S. bufoniformis).
We think that the bacteria present in the less-susceptible species might be playing a defensive role against pathogens like Bd. If these bacteria indeed have antifungal properties, what are the factors determining the presence of these antifungal bacteria on the skin of less susceptible species? To pursue this idea, we compared the microbial communities of C. fitzingeri in the Darién region with skin communities from regions where the frogs were infected with Bd, in Colón and Panamá provinces (Mamoní, Soberanía and Gamboa). We found that the skin bacterial communities in the infected regions had an increased proportion of bacterial species like Pseudomonas and members of the Actinomycetes. Interestingly, these bacteria are known for their antifungal activities in other amphibians, and therefore it is possible that they might be playing an important role in Bd resistance. Since other factors could be influencing these communities, we are currently analyzing experimental data to determine if Bd infection is driving these changes in the skin microbiota.
How can we use the information we have gathered to protect amphibians that do not have high proportions of Pseudomonas and Actinomycetes on their skins? Can we culture these bacteria and study their antifungal properties? We are currently analyzing cultured microbes from less susceptible species to determine if they have anti-Bd properties in vitro. If these microbes are indeed effective against Bd, can we use them as skin probiotics for the highly susceptible species? Probiotics are a very promising avenue towards conservation of susceptible amphibians since the skin microbiota has already been manipulated in some species to protect them from Bd. However a lot of additional studies still need to be done to implement this approach successfully.
Belden LK, Hughey MC, Rebollar EA, Umile TP, Loftus SC, Burzynski EA, Minbiole KPC, House LL, Jensen RV, Becker MH, Walke JB, Medina D, Ibáñez R and Harris RN (2015) Panamanian frog species host unique skin bacterial communities. Front. Microbiol. 6:1171. doi: 10.3389/fmicb.2015.01171
,,, , and ISME Journal. doi:10.1038/ismej.2015.234
by Eria Rebollar
FRIDAY 14 August
GAMBOA AMPHIBIAN RESCUE CENTER OPEN HOUSE
Corner of Morrow and Jadwin, Gamboa.
Get a behind the scenes tour of the Gamboa Amphibian Rescue Center
SATURDAY 15 August
Golden EL VALLE DE ANTON, PASEO EL VALLE
Times: Saturday: 11:00am-3:00pm
Educational activities refreshments and games hosted by the El Valle Amphibian Conservation Center and the Golden Frog Mascott.
SUNDAY 16 August
PUNTA CULEBRA NATURE CENTER, AMADOR
Time: 11 am – 4pm
Meet the golden frog mascott, tour an exhibition of Panama’s most beautiful frogs, games activities and refreshments.
WEDNESSDAY AUG 19
NIGHT FROGS at the BIOMUSEO, AMADOR
Frog raffle, photo booth, exhibition and talk with frog experts.
SATURDAY AUGUST 22
MULTIPLAZA PACIFIC MALL, PANAMA CITY
Time: 11AM- 5PM
Face painting, frog jumping, photobooth and acrobatics by La Tribu.
SUNDAY AUGUST 30
GOLDEN FROG RUN, EL VALLE DE ANTON
Time: 7AM, starting at Hotel Campestre
Register for a race for golden frogs hosted by Caminando Panama.
Presented by: Autoridad Nacional del Ambiente, Smithsonian Tropical Research Institute, Fundacion Smithsonian, El Valle Amphibian Conservation Center, Panama Amphibian Rescue and Conservation Project, La Rana Dorada Pub, SENACYT, USAID, National Science Foundation, APRADAP, Uber, Biomuseo, Oferta simple, Live animals, Stratego , Multiplaza Pacifico, North Face, Caminando Panama.
To celebrate the Golden Frog Festival and the conservation of amphibians in Panama you are invited to join us for ‘la Dorada’ 5K /10K /15K run in the beautiful mountains of El Valle de Anton.
The race will be on Sunday August 30 in El Valle de Anton. This annual event is in its second year, organized and hosted by Caminando Panama the North Face and the Smithsonian. Some of the routes have changed, so stay tuned and visit the event facebook page for updates.
Register from July 26 at The North Face – Multiplaza Mall or Hushpuppies Soho – Albrook Mall in Panama City.
Smithsonian Conservation Biology Institute (SCBI) and Smithsonian Tropical Research Institute (STRI) scientists working together as part of the Panama Amphibian Rescue and Conservation Project (PARC) opened a new safe haven for endangered amphibians today, April 8. The state-of-the-art, $1.2 million amphibian center at STRI’s Gamboa field station expands on the capacity of the El Valle amphibian conservation center to implement a national strategy to conserve Panama’s amphibian biodiversity by creating captive assurance populations. Together these form the largest dedicated facility for amphibian conservation in Latin America.
Panama is a biodiversity hotspot for amphibians with more than 200 species of frogs, salamanders and caecilians. For the past 20 years, however, many of Panama’s unique and endemic amphibian species have declined or disappeared as a result of the deadly chytrid fungus that has spread throughout Latin America and the Caribbean. In fact, a third of amphibian species in Panama are considered threatened or endangered. Amphibian conservationists around the world have been working to establish captive populations of the world’s most vulnerable amphibian species to safeguard them from extinction.
“Our biggest challenge in the race to save tropical amphibians has been the lack of capacity,” said Brian Gratwicke, amphibian scientist at SCBI and international coordinator of PARC. “This facility will allow us to do so much more. We now have the space needed to safeguard some of Panama’s most vulnerable and beautiful amphibians and to conduct the research needed to reintroduce them back to the wild.”
The center features a working lab for scientists, a quarantine space for frogs collected from the wild and amphibian rescue pods capable of holding up to 10 species of frogs. In the working lab, SCBI scientists will continue research focusing on things like a cure for chytrid. Seven amphibianrescue pods house the amphibian collection and colonies of insects needed to feed them. Amphibian rescue pods are constructed from recycled shipping containers that were once used to move frozen goods around the world and through the Panama Canal; they have been retrofitted to become mini-ecosystems with customized terrariums for each frog species.
“Our project is helping implement the action plan for amphibian conservation in Panama, authored by Panama’s National Environmental Authority—now Environment Ministry—in 2011,” said Roberto Ibañez, STRI project director for PARC. “This is only possible thanks to the interest in conservation of amphibian biodiversity by the government of Panama and the support we have received from businesses in Panama.”
The new rescue lab will be crucial to ongoing breeding efforts and breakthroughs, such as the successful hatching of an Andinobates geminisae froglet. SCBI and STRI scientists hatched the first A. geminisae froglet in human care in one of the amphibian rescue pods at the existing Gamboa amphibian conservation center. The tiny poison frog species, smaller than a dime, was discovered and described for the first time in Panama in 2014. They simulated breeding conditions in a rescue pod. The new facility will provide much-needed space to grow and expand, allowing them to build assurance populations for many more species. A small exhibition niche provides a window directly into an active rescue pod, where visitors can see rescued frogs and scientists as they work to conserve these endangered frogs.
PARC is a partnership between the Houston Zoo, Cheyenne Mountain Zoo, Zoo New England, SCBI and STRI. Funding for the new facilities was provided by Defenders of Wildlife, Frank and Susan Mars, Minera Panama, the National Science Foundation and USAID.
As a research facility, PARC is not open to the public. However, there are interpretive panels and a window into the research pod where visitors can get a glimpse of the project in action. To learn more, the public is welcome to visit the new Fabulous Frogs of Panama exhibit at the Smithsonian’s Punta Culebra Nature Center, located on the Amador Causeway.
Smithsonian Conservation Biology Institute (SCBI) and Smithsonian Tropical Research Institute (STRI) scientists working as part of the Panama Amphibian Rescue and Conservation Project hatched the first Andinobates geminisae froglet born in captivity. The tiny dart frog species only grows to 14 millimeters and was first collected and described last year from a small area in central Panama. Scientists collected two adults to evaluate the potential for maintaining the species in captivity as an insurance population.
“There is a real art to learning about the natural history of an animal and finding the right set of environmental cues to stimulate successful captive breeding,” said Brian Gratwicke, amphibian conservation biologist at SCBI and director of the Panama Amphibian Rescue and Conservation Project. “Not all amphibians are easy to breed in captivity, so when we do breed a species for the first time in captivity it is a real milestone for our project and a cause for celebration.”
Scientists simulated breeding conditions for the adult frogs in a small tank. The frogs laid an egg on a bromeliad leaf, which scientists transferred to a moist petri dish. After 14 days, the tadpole hatched. Scientists believe adult A. geminisae frogs may provide their eggs and tadpoles with parental care, which is not uncommon for dart frogs, but they have not been able to determine if that is the case. In the wild, one of the parents likely transports the tadpole on his or her back to a little pool of water, usually inside a tree or on a bromeliad leaf.
After the tadpole hatched, scientists moved it from the petri dish to a small cup of water, mimicking the small pools available in nature. On a diet of fish food, the tadpole successfully metamorphosed into a froglet after 75 days and is now the size of a mature adult.
Panama Amphibian Rescue and Conservation Project scientists are unsure if A. geminisae is susceptible to the amphibian-killing chytrid fungus. However, since it is only found in a small area of Panama and is dependent on primary rain forests, which are under pressure from agricultural conversion, they have identified it as a conservation-priority species.
The Panama Amphibian Rescue and Conservation Project breeds endangered species of frogs in Gamboa, Panama and El Valle, Panama. The Panama Amphibian Rescue and Conservation Project is a partnership between the Houston Zoo, Cheyenne Mountain Zoo, Zoo New England, SCBI and STRI. This study was supported by Minera Panama.
The toad mountain harlequin frog is all decked out in orange and black for Halloween! Atelopus certus is a biological treasure found only in Panama. This terrestrial species has a golden iridescent hue with spots like a giraffe. In its natural setting, the toad mountain harlequin frog can be found streamside or on mossy rocks in moist lowland and mountain forests. We have a healthy population in captivity to safeguard against predicted chytridomycosis-related declines.
Atelopus certus is endemic to Panama and identified only on a single mountain range in the south-western Darien region. Before 2011, this species was quite common within its small known range, and they were still abundant in 2013, but they are predicted to decline severely once chytridiomycosis arrives in that region. Thankfully, due to the swift action of the PARC project, Atelopus certus is being successfully reproduced in captivity. The Gamboa ARC has bred a very stable population
Did you know? The Smithsonian Channel documentary “Mission Critical: Amphibian Rescue” recounts the valiant rescue effort to save this species from imminent extinction.
Post by Dara Wilson
Beauty is in the eye of the beholder! The bright red eyes, and blue striped sides of Agalychnis callidryas are a defense mechanism the frog uses to surprise potential predators, and avoid predation. During the day the red-eyed tree frog folds its legs at its sides, closes its eyes, and sleeps, effectively camouflaging itself on green leaves. You can observe this behavior in their natural habitat of low to mid-elevation rainforests from the Yucatan to Colombia. They are considered a species of least concern according to the IUCN, and are abundant throughout their range. We also have these beauties on display in our exhibit Fabulous Frogs of Panama at Punta Culebra Nature Center.
Did you know? Red-eyed tree frogs lay their eggs on plants overhanging the wáter, and when they hatch the tadpoles fall into the wáter. Eggs in the trees can be eaten by wasps, snakes, or katydids, or killed by pathogenic fungus. Embryos can hatch early to escape from attacks by egg predators and pathogens, or in response to abiotic threats, but they typically hatch later if undisturbed. Thus tadpoles enter the water at different ages, sizes and stages of development. Tadpoles that were induced to hatch early are more likely to be killed by aquatic predators and less likely to survive to metamorphosis. After a month or more in the water, the tadpoles metamorphose into froglets. Metamorphs on land remain relatively inactive near the pond while they absorb their tails, then climb up into the trees and disappear. We know very little about their lives as juveniles.
Snake induced hatching of red-eyed tree frogs.
Video and information by Karen Warkentin Lab
Post by Hannah Arney