Ever wonder how deep-sea fish and other animals are able to survive in an environment where the water pressure would kill us humans? Well, the secret lies in a chemical that occurs naturally in their cells – and we now have a new understanding of how that chemical works.
First of all, you might think that the intense water pressure – which reaches 8 tons (7.25 tonnes) per square inch at the bottom of the Mariana Trench – would simply squash a person like they were a bug. There's more to it than that, however.
Ordinarily, under normal atmospheric pressure, the water molecules within a living cell form a tetrahedron-like network. If that network changes shape – such as through the external application of pressure – proteins in the cell likewise get distorted, preventing vital bio-chemical processes from taking place. When this happens on a whole-body scale, it results in the death of the organism.
Back in the mid-90s, it was found that a molecule known as TMAO (trimethylamine N-oxide) protects those proteins from such distortion.
Led by Prof. Paul H Yancey, a team at Washington state's Whitman College observed that TMAO increases linearly with depth in the tissue of marine fish and other animals such as squid and crustaceans. "The only environmental factor that increases linearly with depth is pressure," Yancey told us. "Pressure has long been known to inhibit functions and distort shapes of proteins, the key active biomolecules of all life."
At the time, the exact means by which TMAO serves its protective role wasn't fully understood. A recent study, however, has shed more light on the manner in which the chemical keeps water molecule networks – and thus cell proteins – from becoming distorted.
Building on previous research, University of Leeds scientists Dr. Harrison Laurent and Prof. Lorna Dougan fired neutron beams at water samples with and without added TMAO, which were being stored at either high or low pressure. When the samples were analyzed, it was found that the hydrogen bonds in the non-TMAO water molecules became distorted under pressure, and the molecule networks in general became compacted. In the TMAO-boosted samples, however, the hydrogen bonds were strong and stable, and the network structure was maintained.
"The TMAO provides a structural anchor which results in the water being able to resist the extreme pressure it is under," said Laurent. "The findings are important because they help scientists understand the processes by which organisms have adapted to survive the extreme conditions found in the oceans."
A paper on the research was recently published in the journal Communications Chemistry.
Source: University of Leeds
