Tag Archives: frogs

New Study Reveals Insights into Frogs’ Evolutionary Success

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New Research Reveals Frogs Have Preserved Their Ecology for 45 Million Years

Frog melanosome geometry study shows similarities between ancient and modern frog eyes. Image credit: Falk et al., doi: 10.1016/j.isci.2025.114220.

This groundbreaking study led by University College Cork investigates 45 million-year-old frog fossils from Geiseltal, a notable paleontological site in central Germany.

These remarkable fossils preserve not only skin remnants but also microscopic fossilized cell structures known as melanosomes.

Melanosomes are essential for synthesizing, storing, and transporting melanin, the pigment responsible for the coloration of skin, hair, and eyes.

Like contemporary frogs, these ancient melanosomes are found in various body areas, including the eyes, skin, and internal organs.

While melanosome shapes differ between fossilized and modern soft tissues, the shapes in the eyes and internal organs remain consistent.

Dr. Valentina Rossi, a researcher at University College Cork, stated, “The shape of melanosomes may correspond to different functions across tissues, including photoprotection and homeostasis.”

Dr. Daniel Falk, also from University College Cork, noted, “The unchanged shape of eye melanosomes over millions of years suggests their function has remained constant, indicating that no evolutionary changes were necessary.”

Some frog species appear to maintain ancestral traits rather than evolving new characteristics.

This research confirms that frogs have preserved their ecological niche for at least 45 million years, adapting to activities such as hunting and mating during dawn and night.

This study is the first to analyze a large dataset of both extant and fossil melanosomes from frogs.

Utilizing advanced electron microscopy and synchrotron X-ray fluorescence analysis, researchers gained insights that were unavailable in the early 20th century when the fossils were first discovered.

Professor Maria McNamara emphasized, “Integrating fossil and living species data in paleontological research can illuminate our understanding of evolutionary processes.”

“We are just beginning to recognize that melanin may serve as a significant evolutionary signal.”

Read the full study published in this month’s iScience magazine here.

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Daniel Falk et al. “Evolutionary Constraints on Melanin over 45 Million Years.” iScience, published online December 17, 2025. doi: 10.1016/j.isci.2025.114220

Source: www.sci.news

Deadly Fungus Causes Ill Frogs to Leap Great Distances, Possibly in Search of Mates

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Bellow’s alpine tree frogs enhance their jumping ability when infected with a common fungus

Robert Valentich/naturepl.com

The chytrid fungus is a lethal pathogen affecting amphibians amid an ongoing global crisis, capable of wiping out entire populations. Yet, for one endangered frog species in Australia, the infection has led to an unusual positive effect: significantly larger hops.

Verreaux’s alpine tree frog (Litoria Verouki Alpina) is impacted by the chytrid fungus, Batrachochytrium dendrobatidis. Those infected can leap nearly a quarter further than their uninfected counterparts.

“These findings remind us of the incredible resilience of these amphibians and their responses to threats from this daunting pathogen. Remarkably, their bodies can display unexpected adaptations,” says Teagan McMahon from the University of Connecticut in New London, who was not involved in the research.

Alexander Wendt and colleagues at the University of Melbourne, Australia, investigated the impact of Bd infection on the health of alpine tree frogs, using their locomotion as an indicator of physiological health.

In their laboratory study, the researchers separated 60 frogs into groups based on infection status. Wendt and his team assessed how the frogs responded to extreme temperature conditions and measured their jumping distances when gently stimulated.

Remarkably, six weeks after infection, the frogs that had contracted Bd exhibited an increase in jumping distance of nearly 24% compared to uninfected ones. Typically, in other amphibian species, energy reserves are drained as the immune system combats the fungus. The physiological responses to Bd can vary significantly among amphibian species, offering temporary advantages in cases of sublethal infections.

“However, as soon as clinical symptoms emerge, it becomes exceedingly challenging for most species,” Wendt notes.

The immune response of alpine tree frogs does not appear robust enough to hinder their reaction to Bd, suggesting that such enhancements may aid them in locating mates quickly before their condition worsens. Other frog species are also known to amplify their mating calls when infected with Bd.

This short-term bolstering of jumping ability can be advantageous when faced with Bd. “From an evolutionary standpoint, it makes sense,” McMahon adds. “Enhanced mobility may contribute to increased transmission rates and prolong the host’s lifespan.”

The influence of Bd on amphibians is increasingly recognized as being shaped by complex interactions between host biology, the fungus, and the surrounding environment. “All we can do is gather as much information as possible to assist these species in surviving and mitigating the spread of Bd before it reaches a critical point,” Wendt emphasizes.

Topic:

  • Animal Behavior/
  • Amphibian

Source: www.newscientist.com

Survival of Endangered Frogs Boosted by Winter Sauna Treatment for Fungal Disease

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Green and gold bell frogs in an artificial hotspot shelter

Anthony Waddle

One of Australia’s most endangered amphibians can fight off a deadly fungal infection with the help of a naturally heated shelter that researchers are calling a “frog sauna.”

The disease, chytridiomycosis, has wiped out about 100 species of frogs, toads and salamanders worldwide.

Green and gold bell frog (Litoria aureaThe fungus was once widespread along the south-eastern coast of Australia, but its range has shrunk by 90 percent, and although other factors such as habitat loss are also at play, chytrid is thought to be the greatest threat to the endangered species.

It has long been known that warm temperatures suppress fungal infections, and many frog species, including the Japanese bush frog, are susceptible to the disease in winter when it’s hard for them to stay warm, especially when it’s hard to find a warm place.

To learn more, Anthony Waddle The researcher, from Macquarie University in Sydney, and his colleagues studied two groups of captive frogs that were intentionally infected with chytridiomycosis over the winter.

The first group was provided with bricks with holes in them in an unshaded greenhouse shelter where temperatures rose to nearly 40°C (104°F), while the second group was provided with bricks in a shaded greenhouse shelter where temperatures rose to 35°C (95°F).

Frogs that were given warmer shelter had 100 times fewer chytrid spores on their skin than other groups.

Although chytrid has difficulty growing above 28°C (82°F), warmer temperatures appear to activate the frogs’ immune systems, Waddle said.

“Using shelter to survive is like a vaccination for the frogs,” Waddle says, “and we’ve shown that firefly frogs can develop resistance after heat has cleared their infection, potentially making them 22 times more likely to survive future infections in cold environments.”

Although the researchers have only tested the shelter on one species at this stage, they believe the technology could be used with other animals threatened by chytrid fungus, as long as they seek out natural warmth when it’s cold. Waddle says there are at least six Australian animal species that could benefit from the technology.

Importantly, these thermal shelters are easy and inexpensive to set up: “All you need is a small vegetable greenhouse from the hardware store and a few bricks, and it will only cost about $60-70. [Australian] “It will cost a few hundred dollars to build,” Waddle said, “and I can envision people putting them in their backyards to help the frogs through the winter.”

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Source: www.newscientist.com

Safeguarding Poison Dart Frogs from Their Lethal Toxins

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Scientists have discovered a “toxin sponge” protein in poison dart frogs that safely stores dangerous alkaloids, offering the possibility of a new approach to treating poisoning in humans. (Artist’s concept) Credit: SciTechDaily.com

The newly identified protein helps poison dart frogs accumulate and store powerful toxins in their skin that they use in self-defense against predators.

Scientists announced that they have identified a protein that helps poison dart frogs safely accumulate their namesake toxin, according to a study published Dec. 19 in the journal Nature. e-life.

The discovery solves a long-standing scientific mystery and could suggest potential therapeutic strategies to treat humans addicted to similar molecules.

Alkaloids: from coffee to frog skin

Alkaloid compounds such as caffeine make coffee, tea, and chocolate delicious and comforting, but they can be harmful if consumed in large amounts. In humans, the liver can safely metabolize moderate amounts of these compounds. Small poison dart frogs ingest far more toxic alkaloids in their diet, but instead of breaking them down, they accumulate them in their skin as a defense mechanism against predators.

“It has long been a mystery how poison dart frogs are able to transport highly toxic alkaloids into their bodies without being poisonous themselves,” said lead author and doctoral student in the Department of Biology at Stanford University in California, USA. Aurora Álvarez Buira says. “We aimed to answer this question by searching for proteins that could bind and safely transport alkaloids in poison dart frog blood.”

Diablito poison dart frog, Uofaga Silvatica, native to Colombia and Ecuador. Credit: Marie-Therese Fischer (CC BY 4.0)

Uncover the secrets of frogs

Alvarez-Buylla and colleagues used compounds similar to poison dart frog alkaloids as a kind of “molecular fishing hook” to attract and bind proteins in blood samples taken from poison dart frogs. The alkaloid-like compounds were bioengineered to glow under fluorescent lights, allowing the researchers to watch proteins bind to the decoys.

They then separated the proteins to see how each protein interacted with the alkaloids in solution. They discovered that a protein called alkaloid-binding globulin (ABG) acts like a “toxin sponge” that collects alkaloids. They also identified how proteins bind to alkaloids by systematically testing which parts of the protein are needed to successfully bind the alkaloids.

Impact on humans and future research

“The way that ABG binds to alkaloids is similar to the way that proteins that transport hormones in human blood bind to their targets,” Álvarez Buira explains. “This finding may suggest that hormone-processing proteins in frogs have evolved the ability to manage alkaloid toxins.”

The authors say the similarities with human hormone transport proteins could be a starting point for scientists to try bioengineering human proteins that “sponge” with toxins. “If successful, these efforts could provide new ways to treat certain addictions,” said lead author Lauren O’Connell, an assistant professor of biology at Stanford University and a member of the Wu Tsai Institute for Neuroscience. he says.

“Beyond potential medical relevance, we have achieved a molecular understanding of a fundamental part of poison dart frog biology, which will inform future research on biodiversity and the evolution of natural chemical defenses.” “This will be important for research,” concludes O’Connell.

Reference: “Binding and isolation of poison dart frog alkaloids” plasma Aurora Alvarez Buira, Marie Therese Fisher, Maria Dolores Moya Garzon, Alexandra E. Rangel, Elisio E. Tapia, Julia T. Tanzo, H. Tom So, Luis A. Coloma, Written by Jonathan Z. Long and Lauren A. O’Connell, December 19, 2023. e-life.
DOI: doi:10.7554/eLife.85096

Funding: National Science Foundation, New York Stem Cell Foundation, National Science Foundation Graduate Research Fellowship Program, Howard Hughes Medical Institute, Alfonso Martín Escudero Foundation, Wu Tsai Human Performance Alliance.

Source: scitechdaily.com