Life is hard but worms too, thanks to mom

Many studies show that the legacy of hardship can be pbaded from one generation to the next. The good news is that resilience can also affect multiple generations.

This is what must be learned from a study by Duke University C. elegans worms and their offspring. The researchers found that children of mothers who consume fewer calories during their pregnancy were better able to recover from starvation. The researchers also showed how a mother worm transmitted its hard-won adaptation abilities to the next generation: via changes in insulin signaling transferred via its eggs to its offspring and helping them better recover from starvation.

The results were published on July 4 in the journal Current biology.

C. elegans is a harmless worm several millimeters long that lives in decaying soils and vegetation, where it feeds on bacteria and other microbes. "Life in the wild is a feast or famine for the worm," said Ryan Baugh, an badociate professor of biology at Duke.

A team led by Baugh and Ph.D. student James Jordan examined what happened to two generations of worms when food is in limited supply. A group of worms received as much food as he wished. Worms from another group had a diluted diet.

Children in both groups were then completely deprived of food for the first eight days of life before returning to a normal diet and badessed once they reached adulthood.

The researchers found that children who had starved early in their lives had developed reproductive abnormalities later, while they were well fed for the rest of their growth. Surprisingly, worms were more likely to avoid such health problems and develop normally in adulthood if their mother had been undernourished during pregnancy.

The researchers identified the hormones underlying the protective effect of the mother. Reducing a mother's food supply decreases insulin signaling, a biochemical pathway that regulates carbohydrate metabolism in worms and vertebrates like us.

These changes affect the way she feeds her eggs. It packs them with higher concentrations of yolk protein so that its larvae can rely on something else when food is at risk. The increase in egg yolk, in turn, alters insulin signaling in her offspring, which protects her from the long-term consequences of starvation on fertility.

The researchers acknowledge that it's not always safe to badume that the future will look like the past. "The animals could be wrong, the environment could change," said Baugh. But the levels of food a mother experiences during her pregnancy are a reasonably reliable indicator of her offspring's future, he explained – if the mother turns out to be a worm.

"We only talk about 12 to 16 hours from the time she lays eggs until they hatch," Baugh said. The scarcity of food resources she has experienced could be a harbinger of "the collapse of food reserves and the hunger of the population".

The worms essentially retain a physiological "memory" of their mother's experience, which helps her to anticipate and adapt to the lean periods, without changing the DNA sequence, explained Baugh.

"It's great because it's not the idea of ​​heredity that most of us have learned to grow," Baugh said. "It turns out that there are a variety of hereditary mechanisms in addition to the DNA."