Everyone would have died long ago, but a Naked mole-rat will be unimpressed: the curious rodents can survive more than a quarter of an hour without oxygen. Because they sometimes behave like plants.
They can survive without oxygen. As if Naked mole-rats had not already made us sufficiently aware of the extraordinary habilities they possess. If you look away from the look, the small animals have brought it quite far:
No other rodent can get as old as they can. Its maximum lifespan exceeds 30 years, making this animal the longest-living rodent. 4 With about 30 years, Naked mole-rats live ten times longer than similar large rodents like mice and rats. Despite their high age, naked mules do not develop cancer. They hardly feel pain. In addition, nudge mules always have company: They live similar to many insects in states with 200 to 300 animals and clear roll distribution.
Naked mole rats pose a challenge to the theories that link ageing, cancer and redox homeostasis. Although characterized by significant oxidative stress, the naked mole rat proteome does not show age-related susceptibility to oxidative damage or increased ubiquitination. Here we report the sequencing and analysis of the naked mole rat genome, which reveals unique genome features and molecular adaptations consistent with cancer resistance, poikilothermy, hairlessness and insensitivity to low oxygen, and altered visual function, circadian rythms and taste sensing. This information provides insights into the naked mole rat’s exceptional longevity and ability to live in hostile conditions, in the dark and at low oxygen. 4
The latter has apparently helped them to find another unusual ability: the rodents can survive up to 18 minutes without oxygen, researchers report by Gary Lewin from the Berlin Max Delbrück Center for Molecular Medicine in the Helmholtz Association in the specialist magazine "Science".
Any other land-based mammal would have long since stifled. whales and seals have found their own way to overcome extensive dives: They can store considerable amounts of oxygen in their muscle tissue. Man survives only a few minutes without oxygen, then brain cells die off.
Naked mole-rats, on the other hand, are dependent on oxygen deficiency, the researchers believe. In the underground tunnels in the hot semi-desert of East Africa, where the rodents live, it is extremely stuffy, especially when hundreds of animals live together in a narrow space. If the air becomes scarce, the naked mullets fall into a kind of winter sleep. The heart hits only 50 times a minute instead of 200 times. As soon as the oxygen content rises again, the animals wake up and continue as if nothing had happened.
Fructose instead of glucose
This succeeds in the Naked mole-rats, because they use fruit sugar (fructose) as an energy supplier for brain cells. It is true that many mammals can utilize fruit sugar, but only in certain tissues - for example, in the liver. The brain cells, on the other hand, depend on glucose.
Not so with the Naked mole-rats: if the oxygen in the construction is not sufficient to gain energy from glucose, the naked mullets give fructose into the blood. Their brain cells have pumps and enzymes that can absorb and utilize the sugar.
"This is not known to any other mammal," says Thomas Park of the University of Illinois, Chicago, who led the study with Lewin. "It is more like the metabolism of plants." In tissue samples of the rodents, which were obtained in the case of oxygen deficiency, the researchers found, in addition to fruit sugar, also ordinary household sugar (sucrose), which otherwise occurs only in the tissue of plants.
The researchers hope that in the future they can also make human brain cells use fruit and household sugar as an energy supplier. "We would like to protect patients from the effects of oxygen deficiency, the heart attack or stroke within minutes," says Lewin. To what extent this is actually possible is currently uncertain.
From the way they communicate, to the way they breed is very different. Although they are not the most beautiful to look at, they are one of the most fascinating. These animals are far from boring and ordinary. 1
The naked mole rat is also the only mammal that lives in a “eusocial” society, similar to that of bees. Only a few of the mole rats get to breed with one queen, while the rest gather food and maintain the nest. 3
Hey, if you want to live a long, cancer-free life, and you don’t mind the risk of a few side-effects like being bald, blind, cold-blooded, and living underground like a drone in a hive, you might consider signing up for a DNA transplant.
The eyes look smaller on the outside, but that belies their internal complexity. The scientists “discovered that in contrast to previous assumptions, the eyes of subterranean African mole-rats have a rather well-structured retina with an unusually high proportion of cone photoreceptors,” says the report. Since cones are the photoreceptors for daylight vision, “their usefulness in the lightless world of mole-rats is puzzling.” Also puzzling was that 90% of the cones are sensitive to blue light, whereas in most mammals 90% are sensitive to green. “The density of rods, the photoreceptors for low-light night vision,” furthermore, “is much lower in the mole-rats than in nocturnal surface-dwelling rodents.” These findings were the opposite of what was expected:
In summary, the photoreceptors of African mole-rats show stark deviations from the common mammalian pattern. But none of these peculiarities fit the concept of a general regression of the retina in adaptation to a lightless living environment. Evolutionary biology would predict that obsolete structures are removed because they are metabolically too expensive. Hence these photoreceptor features should be interpreted as specializations for particular visual needs. 5
Fructose-driven glycolysis supports anoxia resistance in the naked mole-rat 2
The African naked mole-rat’s (Heterocephalus glaber) social and subterranean lifestyle generates a hypoxic niche. Under experimental conditions, naked mole-rats tolerate hours of extreme hypoxia and survive 18 minutes of total oxygen deprivation (anoxia) without apparent injury. During anoxia, the naked mole-rat switches to anaerobic metabolism fueled by fructose, which is actively accumulated and metabolized to lactate in the brain.
Proponents of evolution have another enigma to explain....