A deep-sea isopod. [Photo provided to chinadaily.com.cn]
Chinese scientists have found a mechanism that may explain how giant deep-sea isopods are able to survive for extraordinarily long periods without food.
In one widely reported case, a giant deep-sea isopod remained alive for more than five years after its last meal.
The study was carried out by researchers from the Chinese Academy of Sciences' Institute of Oceanology in Shandong province, the Chinese University of Hong Kong, and Northwestern Polytechnical University. Their findings were published on Friday in the journal Cell.
A deep-sea isopod. [Photo provided to chinadaily.com.cn]
Despite living in nutrient-poor waters, deep-sea isopods grow to giant sizes, raising the question of how they sustain such high energy demands. The researchers studied two species living at different ocean depths, integrating comparative genomics with morphological, physiological, behavioral, and metagenomics analyses.
A deep-sea isopod. [Photo provided to chinadaily.com.cn]
Their study found a dual survival strategy in deep-sea isopods to cope with oligotrophic conditions: an enlarged stomach, accounting for about two-thirds of the animal's body, that can store large amounts of food, and an extremely low basal metabolic rate. It also identified a gene named ND1 that originated from an exogenous symbiotic bacterium and integrated into the isopod genome, which may play a critical role in the duration of starvation.
To test the gene's function, the research team inserted ND1 into zebrafish, nematodes, and human cell lines. The experiments showed that ND1 increased energy use at normal temperatures but reduced energy metabolism under low-temperature conditions. In zebrafish, it improved starvation tolerance by 37 percent.
A deep-sea isopod. [Photo provided to chinadaily.com.cn]
"Our work not only successfully deciphers the mystery of ultra-long starvation tolerance in deep-sea isopods, but also provides an important paradigm for understanding how life balances growth and survival in extreme environments," said Yuan Jianbo, first author of the study and a research fellow at the Institute of Oceanology.
The findings may also provide insights for research on longevity, obesity treatment, and aquaculture breeding, he added.
