Suspended animation in African lungfish

03 Aug 2015 NUS scientists discovered aestivation in the African lungfish in arid conditions at high temperature involves the up- and down-regulation of diverse cellular activities.

African lungfish, Protopterus annectens (see Figure), can undergo aestivation (suspended animation) without food and water for 3 to 5 years; arousal occurs when water becomes available. A team led by Prof IP Yuen Kwong from the Department of Biological Sciences in NUS has examined the differential gene expression in the liver of P. annectens after 6 months of aestivation as compared with the freshwater control, or after 1 day of arousal from 6 months aestivation as compared with 6 months of aestivation. Results obtained signified the importance of sustaining a low rate of waste production and conservation of energy store during the maintenance phase, and the dependence on internal energy store for repair and structural modification during the arousal phase, of aestivation.

During suspended animation, animals become inactive with absolutely no intake of food and water, and without urine or waste production, for an extended period. They enter into a state of torpor, slowing down the biological time in relation to the clock time. Suspended animation has long fascinated scientists because of its great application potentials in fields ranging from medicine to space travel. If suspended animation can be achieved in human, surgeons would have more time to operate on patients during critical moments when the blood circulation stops, and the dream of long distance space travel can be realized.

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Protopterus annectens aestivating in a dried mucus cocoon [Image credit: IP YK]



Hiong KC, Ip YK, Wong WP, Chew SF. “Differential gene expression in the liver of the African lungfish, Protopterus annectens, after 6 months of aestivation in air or 1 day of arousal from 6 months of aestivation.” (2015) PLoS ONE 10(3): e0121224. doi:10.1371/journal.pone.0121224