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Root effect

In today's article we are going to explore the fascinating world of Root effect, a topic that has captured the attention of humanity for decades. From its origins to its current impacts, Root effect has played a fundamental role in our lives, influencing the way we think, behave and relate to the world around us. Throughout this article, we will examine the various aspects of Root effect, from its historical importance to its relevance today, providing an in-depth and comprehensive look at this intriguing topic. Join us on this journey of discovery as we explore the mysteries and wonders of Root effect.

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The Root effect is a physiological phenomenon that occurs in fish hemoglobin, named after its discoverer R. W. Root. It is the phenomenon where an increased proton or carbon dioxide concentration (lower pH) lowers hemoglobin's affinity and carrying capacity for oxygen.[1][2] The Root effect is to be distinguished from the Bohr effect where only the affinity to oxygen is reduced. Hemoglobins showing the Root effect show a loss of cooperativity at low pH. This results in the Hb-O2 dissociation curve being shifted downward and not just to the right. At low pH, hemoglobins showing the Root effect don't become fully oxygenated even at oxygen tensions up to 20kPa.[2] This effect allows hemoglobin in fish with swim bladders to unload oxygen into the swim bladder against a high oxygen gradient.[3] The effect is also noted in the choroid rete, the network of blood vessels which carries oxygen to the retina.[3] In the absence of the Root effect, retia will result in the diffusion of some oxygen directly from the arterial blood to the venous blood, making such systems less effective for the concentration of oxygen.[4] It has also been hypothesized that the loss of affinity is used to provide more oxygen to red muscle during acidotic stress.[5]

References

  1. ^ Ito N.; Komiyama N. H.; Fermi G. (1995). "Structure of Deoxyhaemoglobin of the Antarctic Fish Pagothenia bernachii with an Analysis of the Structural Basis of the Root Effect by Comparison of the Liganded and Unliganded Haemoglobin Structures". Journal of Molecular Biology. 250 (5): 648–658. doi:10.1006/jmbi.1995.0405. PMID 7623382.
  2. ^ a b Pelster B (December 2001). "The generation of hyperbaric oxygen tensions in fish". News Physiol. Sci. 16 (6): 287–91. doi:10.1152/physiologyonline.2001.16.6.287. PMID 11719607. Archived from the original on 2016-03-03. Retrieved 2011-03-06.
  3. ^ a b Verde, C., A. Vergara, D. Giordano, L. Mazzarella, and G. di Prisco. 2007. The Root effect - a structural and evolutionary perspective. Antarctic Science 19:271-278.
  4. ^ Berenbrink M, Koldkjaer P, Kepp O, Cossins AR (March 2005). "Evolution of oxygen secretion in fishes and the emergence of a complex physiological system". Science. 307 (5716): 1752–7. doi:10.1126/science.1107793. PMID 15774753. S2CID 36391252.
  5. ^ Rummer JL, McKenzie DJ, Innocenti A, Supuran CT, Brauner CJ (June 2013). "Root Effect Hemoglobin May Have Evolved to Enhance General Tissue Oxygen Delivery" (PDF). Science. 340 (6138): 1327–9. doi:10.1126/science.1233692. hdl:2158/1022682. PMID 23766325. S2CID 43241955.
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