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

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)


Unlike some other reproductions of classic texts (1) We have not used OCR(Optical Character Recognition), as this leads to bad quality books with introduced typos. (2) In books where there are images such as portraits, maps, sketches etc We have endeavoured to keep the quality of these images, so they represent accurately the original artefact. Although occasionally there may be certain imperfections with these old texts, we feel they deserve to be made available for future generations to enjoy.

Kyphosis and Other Variations in Soft-Shelled Turtles

Kyphosis and Other Variations in Soft-Shelled Turtles
by Smith Hobart M (Hobart Muir) (Creator)


Unlike some other reproductions of classic texts (1) We have not used OCR(Optical Character Recognition), as this leads to bad quality books with introduced typos. (2) In books where there are images such as portraits, maps, sketches etc We have endeavoured to keep the quality of these images, so they represent accurately the original artefact. Although occasionally there may be certain imperfections with these old texts, we feel they deserve to be made available for future generations to enjoy.

THE CANTOR'S GIANT SOFT-SHELLED TURTLE Do Your Kids Know This?: A Children's Picture Book (Amazing Creature Series) (Volume 47)

THE CANTOR'S GIANT SOFT-SHELLED TURTLE Do Your Kids Know This?: A Children's Picture Book (Amazing Creature Series) (Volume 47)
by Tanya Turner (Author)


If the Cantor’s Giant Soft-Shelled Turtle’s head seems like a snake’s head to you, that’s because they are both reptiles. This type of animal is also called a Frog-Faced Soft-Shelled Turtle because it somewhat looks like a frog, too (it’s face, at least). The Cantor’s Giant Soft-Shelled Turtle is a very special animal because it currently holds the record for being the biggest existing freshwater turtle. There may have been other species of freshwater turtles that were bigger than the Cantor’s Giant Soft-Shelled Turtle, but they are all extinct. Excited to learn more about the Cantor’s Giant Soft-shelled Turtle? Get a copy of this book and discover more fascinating information about this animal.

THE CANTOR'S GIANT SOFT-SHELLED TURTLE Do Your Kids Know This?: A Children's Picture Book (Amazing Creature Series 47)

THE CANTOR'S GIANT SOFT-SHELLED TURTLE Do Your Kids Know This?: A Children's Picture Book (Amazing Creature Series 47)


If the Cantor’s Giant Soft-Shelled Turtle’s head seems like a snake’s head to you, that’s because they are both reptiles. This type of animal is also called a Frog-Faced Soft-Shelled Turtle because it somewhat looks like a frog, too (it’s face, at least).
The Cantor’s Giant Soft-Shelled Turtle is a very special animal because it currently holds the record for being the biggest existing freshwater turtle. There may have been other species of freshwater turtles that were bigger than the Cantor’s Giant Soft-Shelled Turtle, but they are all extinct.
Excited to learn more about the Cantor’s Giant Soft-shelled Turtle? Get a copy of this book and discover more fascinating information about this animal.

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)


Pp. (8), ii, 174; 120+ color photos, 3 black-and-white photos, some maps. Publisher's original red cloth, lettered in gilt on the spine, color pictorial dust jacket. This work documents the last remaining members of the species, Rafetus swinhoei. This species is found along the Red River and its tributaries in northern Vietnam and in the Yangtze River in China. A related species is found in the basin of the Tigris and Euphrates Rivers in Iraq, Syrian Arab Republic, Turkey, and Khuzestan Province of Iran. The Vietnamese and Chinese species are on the brink of extinction. No ownership marks and no signs of use.

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)




Tortoises, Terrapins & Turtles of Africa

Tortoises, Terrapins & Turtles of Africa
by Struik Nature


Africa has a rich diversity of tortoises, terrapins and turtles. This authoritative field guide is richly illustrated with colour photographs that make for easy identification of the 46 African species; it provides accessible, up-to-date information and distribution maps, and examines how these creatures have adapted to their environments. The book offers an overview of their origins, anatomy and biology, their conservation status and the threats to their survival posed by the destruction of their habitats by man.

standardization of production technology, soft-shelled turtle

standardization of production technology, soft-shelled turtle
by YANG DUO CAI ?LI SHUANG AN (Author)




Turtle power indicating the power diabetes, heart disease - challenge of soft-shelled turtle (1998) ISBN: 488492214X [Japanese Import]

Turtle power indicating the power diabetes, heart disease - challenge of soft-shelled turtle (1998) ISBN: 488492214X [Japanese Import]
by Chihaya Shobo (Publisher)




Secrets of soft-shelled turtle - keep the beauty and youth (HEALTH BOOKS) ISBN: 4874611575 (1987) [Japanese Import]

Secrets of soft-shelled turtle - keep the beauty and youth (HEALTH BOOKS) ISBN: 4874611575 (1987) [Japanese Import]
by Ken Hall friend (Publisher)




© 2016 BrightSurf.com