Camels have a fantastic ability to survive several weeks without taking even a sip of water. Now, we’ve a far better idea of the unknown ingredient that helps their bodies achieve this.
We already know that to save each and every drop of liquid, camels have a number of biological tricks – including large and complex noses that grab at the water within the air leaving their bodies and modified blood which will withstand dehydration.
They can gulp down many liters in matter of minutes when water is out there , which they then only absorb slowly to avoid osmotic shock; additionally, their body temp. fluctuates from 31-41 °C (87- 105 °F) to reduce sweating.
When a person’s runs low on water, our kidneys shift gears to preserve the maximum amount moisture as they can. Water is filtered into tubules in a region called the cortex, where it flows into another part called the medulla. Here, ions from dissolved salt are pumped across membranes to make an imbalance that forces some of the water to return to the blood, with the remain carrying away waste as urine.
Camels’ bodies take this water re-uptake to the maximal, concentrating their urine to a degree we could never manage. In a study examining genes expressed within the cells of Arabian camels’ (Camelus dromedarius) kidneys, a team of researchers compared those from camels that were dehydrated and camels who’d recently had their fill of water.
“We identified many genes and proteins that are significantly changed in both kidney cortex and medulla in dehydrated and rehydrated animals compared to controls,” said University of Bristol animal physiologist Fernando Alvira Iraizoz.
Many of the genes that changed expression in dehydrated camels seemed to be involved in suppressing the fatty substance cholesterol in their kidney cells.
So, Alvira Iraizoz and colleagues measured the quantity of cholesterol in kidney plasma membranes within the dehydrated animals and compared it to the controls. They found dehydrated camels did indeed have less cholesterol in these kidney cell membranes than hydrated ones.
What’s more, genes coding for transporting ions and water channels across the cell membranes were also being expressed more within the dehydrated camels’ kidney cells. Together, these findings support the team’s hunch that dehydration-induced cholesterol suppression allows camels to cling onto more water in their kidneys.
“A decrease within the amount of cholesterol within the membrane of kidney cells would facilitate the movement of solutes and water across different sections of the kidney – a process that’s required to efficiently re-absorb water and produce a highly concentrated urine, thus avoiding water loss,” explained Alvira Iraizoz and molecular neuroendocrinologist Benjamin Gillard, also from the University of Bristol.
In our rapidly warming world, livestock animals which will endure harsh conditions are getting ever more important. The Arabian camel already supports many millions of people since its domestication over 3,000 years ago. They supply milk, meat, clothing, transport, and shelter in several arid parts of our planet.
“Multiomic studies provide very valuable information within the context of desertification and global climate change and might be wont to evaluate how different species will adapt to their already changing environments,” said Alvira Iraizoz.
The researchers are now performing on a same analysis of the camel’s brain, and that they plan on looking into the genetic expression response to severe dehydration in other arid mammals, just like the adorable hopping rodents called jerboa.
This research was published in Communications Biology.