Both avian and non-avian reptiles eliminate excess nitrogen as solid compounds known as “urate,” an evolutionary trait that aids in water conservation. Despite this adaptation, numerous questions regarding the composition, structure, and assembly of these biological materials remain unresolved. In a recent study, researchers from Georgetown University, the International Diffraction Data Center, Chiricahua Desert Museum, and Georgia State University investigated uric acid excretion in the desert. They focused on the ball python (python) along with 20 other reptile species, aiming to uncover efficient and versatile mechanisms for processing both nitrogenous waste and salts.
Thornton et al. investigated the solid urine of over 20 reptile species. Image credit: Thornton et al., doi: 10.1021/jacs.5c10139.
“All living organisms possess some form of excretory system. After all, what enters must eventually exit,” says the chemist from Georgetown University, Jennifer Swift, along with her colleagues.
“In humans, we eliminate excess nitrogen primarily through urine in the forms of urea, uric acid, and ammonia.”
“Conversely, many reptiles and birds efficiently package these nitrogenous compounds into solids, specifically urates, which are excreted through their cloaca.”
Scientists theorize that this process may have evolved to aid in water conservation.
“While crystallizing waste fluids may provide an evolutionary benefit for reptiles, it poses significant challenges for humans,” the researchers noted.
“Excess uric acid in the human body can crystallize in the joints, leading to painful conditions like gout, or form kidney stones in the urinary tract.”
In this recent study, the authors examined urate from over 20 reptile species to understand how these animals safely eliminate crystalline waste.
“Our research stems from a curiosity about how reptiles safely process this substance, and we hope it could inform new approaches to disease prevention and treatment,” Dr. Swift commented.
Microscopic analyses revealed that three species—the ball python, Angora python, and Madagascar tree boa—produce urate consisting of microscopically textured microspheres ranging from 1 to 10 micrometers in diameter.
X-ray examinations indicated that these spheres are comprised of even smaller nanocrystals of uric acid and water.
Furthermore, scientists have found that uric acid plays a crucial role in transforming ammonia into a less harmful solid state.
They hypothesize that uric acid may serve a similar protective function in humans.
“Our investigation of urate produced by various squamate reptiles sheds light on the sophisticated and adaptable systems they employ for managing nitrogenous wastes and salts,” the researchers stated.
“Understanding how dietary habits, environmental conditions, and aging impact sample analysis—along with advancements in instrumentation—offers a more comprehensive insight into the structure and function of biological urates.”
“The specifics of where and how these microspheres are created remain an intriguing question, yet their presence across different uric acid globule species suggests that this low-energy process is optimized under similar selective pressures.”
“Recognizing the role of uric acid in ammonia management could have significant implications for human health, although clinical research is required to verify this hypothesis.”
For further information, refer to the findings published today in the Journal of the American Chemical Society.
_____
Alyssa M. Thornton et al. Uric acid monohydrate nanocrystals: an adaptable platform for nitrogen and salinity management in reptiles. J. Am. Chemistry Society published online October 22, 2025. doi: 10.1021/jacs.5c10139
Source: www.sci.news
