Science Current Events | Science News | Brightsurf.com
 

Soft-shelled turtles urinate through mouth

October 11, 2012
Soft-shelled turtles excrete urea through mouth

Chinese soft-shelled turtles are exquisitely adapted to their aquatic lifestyle, sitting contentedly on the bottom of brackish muddy swamps or snorkelling at the surface to breath. According to Y. K. Ip from the National University of Singapore, they even immerse their heads in puddles when their swampy homes dry up: which intrigued Ip and his colleagues. Why do these air-breathing turtles submerge their heads when they mainly depend on their lungs to breathe and are unlikely to breathe in water? Given that some fish excrete waste nitrogen as urea - in addition to ammonia - and expel the urea through their gills, the team wondered whether the turtles were plunging their heads into water to excrete waste urea through their mouths, where they have strange gill-like projections. Ip and his colleagues publish their discovery that turtles effectively urinate through the mouth in The Journal of Experimental Biology at http://jeb.biologists.org.

Purchasing turtles from the local China Town wet market and immersing them in water for 6 days, the team measured the amount of urea that passed into the turtles' urine and found that only 6% of the total urea that the animals produced was excreted through the kidneys. Removing the turtles from the water and providing them with a puddle to dip their heads into, the team noticed that the turtles submerged their heads occasionally and could remain underwater for periods lasting up to 100 minutes. They also calculated the excretion rate of urea through the mouth by measuring the amount of urea that accumulated in the water and found that it was as much as 50 times higher than the excretion rate through the cloaca. And when the team injected urea into the turtles and measured their blood- and saliva-urea levels, they realised that the saliva-urea levels were 250 times greater than in the blood. The turtles were dipping their heads into water to excrete urea through their mouths.

Knowing this, the team reasoned that the animals must produce a specialised class of protein transporters in their mouths to expel the waste and, as these transporters can be deactivated by phloretin, the team decided to test the effect of phloretin on the turtle's ability to excrete urea. When the turtles were supplied with phloretin in their puddle of water, they were unable to excrete urea from their mouths when they submerged their head. And when the team analysed the turtles' cDNA, they found that the animals carried a gene that was very similar to urea transporters found in other animals. Finally, they checked to see if the turtles express this gene in their mouths and found evidence of the mRNA that is necessary to produce the essential urea transporter, allowing the reptiles to excrete urea waste through the mouth.

So, why do Chinese soft-shelled turtles go to such great lengths to excrete urea through their mouths when most other creatures do it through their kidneys? Ip and his colleagues suspect that it has something to do with their salty environment. Explaining that animals that excrete urea have to drink a lot, they point out that this is a problem when the only water available is salty - especially for reptiles that cannot excrete the salts. The team says, 'Since the buccopharyngeal [mouth and throat] urea excretion route involves only rinsing the mouth with ambient water, the problems associated with drinking brackish water- can be avoided'.

The Company of Biologists



More Soft-shelled Turtles Current Events and Soft-shelled Turtles News Articles

Kyphosis and other Variations in Soft-shelled Turtles

Kyphosis and other Variations in Soft-shelled Turtles


This book was converted from its physical edition to the digital format by a community of volunteers. You may find it for free on the web. Purchase of the Kindle edition includes wireless delivery.

North American recent soft-shelled turtles (family Trionychidae) (University of Kansas publications, Museum of Natural History)

North American recent soft-shelled turtles (family Trionychidae) (University of Kansas publications, Museum of Natural History)
by Robert G Webb (Author)




Rafetus, The Curve of Extinction: The Story of the Giant Softshell Turtle of the Yangtze and Red Rivers

Rafetus, The Curve of Extinction: The Story of the Giant Softshell Turtle of the Yangtze and Red Rivers
by Peter C. H. Pritchard (Author)


In this, Dr. Peter Pritchard's eleventh book, he tells the incredible story of the world's rarest turtle, Rafetus swinhoei, a true giant of the chelonian world. This freshwater Loch Ness Monster, is represented by a single mystical giant living in Lake Hoan Kiem in downtown Hanoi, a juvenile in Dong Mo, perhaps a few specimens living in the shadows of deep lakes in nature, and a large adult pair who lived alone as zoo specimens for more than fifty years, separated by thousands of miles. By a miraculous feat of politics, ingenuity, and human labor, these two individuals were brought together for the purpose of saving the species. In RAFETUS: The Curve of Extinction, Dr. Pritchard presents a story of looming loss, but also of hope.

Turtles and Tortoises (Barron's Complete Pet Owner's Manuals)

Turtles and Tortoises (Barron's Complete Pet Owner's Manuals)
by R.D. Bartlett (Author), Patricia P. Bartlett (Author)


Here is detailed information on both land and water species, with specifics on determining sex, life expectancy, housing, feeding, and health care. Books in the comprehensive and popular Barron's Complete Pet Owner's Manuals series advise on feeding, health care, housing, and all other important aspects of responsible pet ownership. Each title is individually written from first page to last by a pet trainer, veterinarian, or other pet-care specialist. All Complete Pet Owner's Manuals are filled with high-quality photos and instructive line art.

100 Questions and Answers of Efficient Breeding of Soft-shelled Turtle (Chinese Edition)

100 Questions and Answers of Efficient Breeding of Soft-shelled Turtle (Chinese Edition)
by Zhao Chun Guang. Dai Hai Ping. (Author)




Fatty acid composition and lipid peroxidation of soft-shelled turtle, Pelodiscus sinensis, fed different dietary lipid sources [An article from: Comparative Biochemistry and Physiology, Part C]

Fatty acid composition and lipid peroxidation of soft-shelled turtle, Pelodiscus sinensis, fed different dietary lipid sources [An article from: Comparative Biochemistry and Physiology, Part C]
by W.Y. Lin (Author), C.H. Huang (Author)


This digital document is a journal article from Comparative Biochemistry and Physiology, Part C, published by Elsevier in 2007. The article is delivered in HTML format and is available in your Amazon.com Media Library immediately after purchase. You can view it with any web browser.

Description:
Juvenile soft-shelled turtles (Pelodiscus sinensis) were fed 7 diets containing 8% of lard, soybean oil, olive oil, menhaden fish oil, or mixtures of 1 to 1 ratio of fish oil and lard, soybean oil, olive oil for 10 weeks. Growth and muscle proximate compositions of the turtles were not affected by different dietary treatments (p>0.05). Fatty acid profiles in muscle polar lipids, muscle non-polar lipids, and liver polar lipids reflected the fatty acid composition of dietary lipid source....

The effects of vitamin E on antiacid stress ability in juvenile soft-shelled turtles (Pelodiscus sinensis) [An article from: Comparative Biochemistry and Physiology, Part C]

The effects of vitamin E on antiacid stress ability in juvenile soft-shelled turtles (Pelodiscus sinensis) [An article from: Comparative Biochemistry and Physiology, Part C]
by X. Zhou (Author), C. Niu (Author), R. Sun (Author)


This digital document is a journal article from Comparative Biochemistry and Physiology, Part C, published by Elsevier in 2004. The article is delivered in HTML format and is available in your Amazon.com Media Library immediately after purchase. You can view it with any web browser.

Description:
We determined the effect of dietary supplementation with vitamin E (0-, 50-, 250-, 500-, 1000- and 5000-mg/kg diet for 4 weeks) on antistress ability in juvenile soft-shelled turtle (Pelodiscus sinensis). Half of the turtles per dose group were treated by acid stress for 24 h. The results showed that phagocytosis of blood cells in the control group significantly decreased after acid stress while the other five groups had no significant changes compared with those of before stress. Serum...

Aquatic Turtles: Sliders, Cooters, Painted, and Map Turtles (Reptile Keeper's Guide)

Aquatic Turtles: Sliders, Cooters, Painted, and Map Turtles (Reptile Keeper's Guide)
by R.D. Bartlett (Author), Patricia Bartlett (Author)


Titles in this series present basic information on reptiles plus specific instructions for their care. Each book opens with a description of the animal as it exists in its natural habitat, then continues with information on its life cycle and distribution in nature. Readers then get advice on selecting a good specimen, determining sex, and providing proper housing, feeding, and health care. Books are heavily illustrated with instructive color photos.

Natural History (Smithsonian)

Natural History (Smithsonian)
by DK Publishing (Author)


A landmark in reference publishing and overseen and authenticated by the Smithsonian Institution's National Museum of Natural History, Natural History presents an unrivaled visual survey of Earth's natural history. Giving a clear overview of the classification of our natural world-over 6,000 species-Natural History looks at every kingdom of life, from bacteria, minerals, and rocks to fossils to plants and animals. Featuring a remarkable array of specially commissioned photographs, Natural History looks at thousands of specimens and species displayed in visual galleries that take the reader on an incredible journey from the most fundamental building blocks of the world's landscapes, through the simplest of life forms, to plants, fungi, and animals.

Turtles: An Extraordinary Natural History 245 Million Years in the Making

Turtles: An Extraordinary Natural History 245 Million Years in the Making
by Carl J. Franklin (Author), David C. Killpack (Illustrator)


Turtles are a species of reptile at its evolutionary zenith, with an ancient lineage stretching back over 200 million years. Under their unmistakable shells, testament to their survival, they harbor a natural history of epochal proportions. This is the engrossing story Turtles tells.

The book offers a full account of the evolution, history, diversity, ecology, and behavior of the turtle, and of the problems facing these reptiles worldwide. The book describes the important role turtles play in their ecosystems, as well as the pressures put upon current populations by habitat destruction, over-collection for the pet trade, and increasing consumption for food.

Accompanying Franklins text are photographs and illustrations testifying to the colorful diversity of the 300...

© 2014 BrightSurf.com