A term in physiology: piezolyte for an osmolyte whose cellular levels respond to hydrostatic and osmotic pressure

The term piezolyte derives from the Greek roots piezo and lytos, referring to something squeezed under pressure and something that is soluble or dissolved, respectively.  The “something”  is a special form of an osmolyte. An osmolyte, dissolved in intracellular liquid, regulates cell properties—mainly the cell's volume—in response to osmotic pressure. A piezolyte performs in response to both osmotic and hydrostatic pressure [1-3].

Piezolytes are organic molecules, which are found in organisms that live in shallow or deep water, where they experience hydrostatic pressure. Examples are the small molecule β-hydroxybutyrate (β-HB) and oligomers composed of β-HB units, identified as intracellular solutes in the deep-sea bacterium Photobacterium profundum [1].

Piezolytes have also been studied in crustaceans and sea cucumbers (down to 2,900 m) and in fish (down to 4,900 m), but it is not yet known how piezolytes perform in animals living at depths down to 10,000 m. The HADES (Hadal Ecosystem Studies) project includes expeditions into the hadal zone of the Kermadec trench near New Zealand and will examine how marine animals adapt to high pressures in the deep sea and which role piezolytes play in cells that grow and function above atmospheric pressures [3].  

Keywords:  biochemistry, microbiology, intracellular solutes, osmosis, marine science.

References and more to explore
[1] Deana Desmarais Martin, Douglas H. Bartlett and Mary F. Roberts: Solute accumulation in the deep-sea bacterium Photobacterium profundum. Extremophiles 2002, 6, pp. 507-514 [bartlettlab.ucsd.edu/Publications_files/Martin2002.pdf].
[2] Paul H. Yancey: Organic osmolytes as compatible, metabolic and counteracting cytoprotectants in high osmolarity and other stresses. The Journal of Experimental Biology 2005, 208, pp. 2819-2830 [jeb.biologists.org/content/208/15/2819.full].
[3] Jane J. Lee: Ocean's Deep, Dark Trenches to Get Their Moment in the Spotlight. Science April 13, 2012, 336 (6078), pages 141and 143. DOI: 10.1126/science.336.6078.141.