Worms self-eat the intestines to age

need to produce eggs from yolks. PHOTO: JAMES KING-HOLMES/SCIENCE SOURCE
tiny nematodes that twist in soil and researchers' labs feed on their own internal organs. The habit of digesting one's gut can help it reproduce, but it also accelerates their aging, according to a new study. These results support the unorthese assumption that humans and other organisms break down as they age, because the characteristics that benefit them when they are young become harmful.
time has done a lot of damage to the worm. Like many people, these worms, which can live for about 3 weeks, get fat as they get older. The bodies of elderly worms are filled with fat stored in the form of egg yolks. These worms are also prone to uterine tumors and withering of the intestines.
what drives the degradation of worms and other organisms? One idea is that aging occurs because molecules such as DNA and proteins accumulate damage and start to fail. Another "uninterrupted hypothesis" holds that organisms break down over time because their ability to survive and reproduce early in life continues to "run" and then become a problem. For example, specific genes that coordinate growth and development are beneficial for young animals. But if they continue to operate in older animals, they can cause cancer.
David Gems, a geneticist at University College London, and colleagues may have found the best example of what the "uninterrupted hypothesis" does. The team found that the worms consumed their intestines to synthesize the egg yolks. This ability to turn organs into yolks may allow young worms to lay eggs, even when food is scarce. However, the worms continue to digest their intestines, even after they stop laying eggs.
Gems and colleagues report in the
journal
that this persistent self-devouring behavior accelerates the aging of worms. When scientists inhibited egg yolk synthesis by changing specific genes, the worms' intestines did not break down and they no longer gain weight. The researchers also found that preventing the intestinal breakdown caused some worms to live longer.
evidence from male worms also supports this view. Male worms are rare - more than 99 percent of them are males and females that excrete eggs and sperm. Male worms usually do not produce egg yolks. Gems and his team noted that their intestines did not deteriorate. But when researchers genetically modified male worms to produce a key egg yolk protein, the animals began to show two previously aging signs: intestinal degradation, and fat began to accumulate. (Source: Zong Hua, China Science Daily)