Get 20M+ Full-Text Papers For Less Than $1.50/day. Start a 7-Day Trial for You or Your Team.

Learn More →

Thin-blooded icefish relocate carbonic anhydrase to gill

Thin-blooded icefish relocate carbonic anhydrase to gill © 2018. Published by The Company of Biologists Ltd | Journal of Experimental Biology (2018) 221, jeb193680. doi:10.1242/jeb.193680 INSIDE JEB gas into bicarbonate. The pH decreased rapidly, confirming that the enzyme is located on blood vessel cell membranes. And when Jonathan Wilson stained the cell membranes with a series of specialised dyes that could only bind to molecules of carbonic anhydrase, he found one form of the enzyme (carbonic anhydrase 4) attached to the membranes lining the inner surface of the gill blood vessels. To confirm the presence of the enzyme, Harter and David Metzger then collected RNA from the fish’s gills, eventually identifying an mRNA molecule that could be translated to produce the carbonic anhydrase 4 enzyme. However, when the team searched for carbonic anhydrase proteins in the gills of a close relative, Notothenia rossii, which has retained its red blood cells despite sharing C. gunnari’s icy waters, they A Champsocephalus gunnari icefish. Photo credit: Michael Axelsson. found none. Few animals can justifiably be called ‘thin Reasoning that it might be might be So, it seems that icefish have relocated blooded’, but Antarctic icefish genuinely situated on the inner surface of gill blood carbonic anhydrase to their gills to are. They lack the brightly pigmented vessels, Harter, Colin Brauner and their overcome the difficulties of carbon red blood cells that usually carry oxygen international team of collaborators began dioxide disposal after trading in their red around the body, although the blood is searching for the elusive enzyme in the blood cells. But they suspect that red- still capable of transporting oxygen to gills of Champsocephalus gunnari blooded fish are unlikely to follow their tissues thanks to the high solubility icefish. their apparently ‘bloodless’ cousin’s of the gas in the frigid Antarctic waters. convenient example, as the enzyme could But the fish face another problem. In most Although Harter was unable to visit drastically disturb the delicate balance bony fish, waste carbon dioxide is carried Antarctica himself, he was fortunate that allows their red blood cells to keep in the blood to the gills in the form of that Kristin O’Brien from University hold of their oxygen cargo when bicarbonate, where it is converted back of Alaska Fairbanks, USA, and Lisa exercising hard. into carbon dioxide in red blood cells by Crockett from Ohio University, USA, sent 10.1242/jeb.193680 an enzyme known as carbonic anhydrase, C. gunnari that they had caught during the before it is exhaled. ‘However this 2015 Antarctic field season. After the fish Harter, T. S., Sackville, M., Wilson, J. M., Metzger, D. C. H., Egginton, S., Esbaugh, A. J., Farrell, strategy is impossible in icefishes, which arrived, he cautiously isolated the outer A. P. and Brauner, C. J. (2018). A solution to have lost red blood cells’, says Till Harter membrane from the cells lining the inside Nature’s haemoglobin knockout: a plasma- from the University of British Columbia, of the gill blood vessels before bathing accessible carbonic anhydrase catalyses CO excretion in Antarctic icefish gills. J. Exp. Biol. Canada. While there is some evidence it in water saturated with CO and 221, jeb190918. that the essential bicarbonate converting measuring how the pH changed – in the protein is harboured somewhere in the hope that any carbonic anhydrase present Kathryn Knight gills, the precise location was not clear. on the membrane surface may convert the [email protected] Inside JEB highlights the key developments in Journal of Experimental Biology. Written by science journalists, each short report gives the inside view of the science in JEB. Journal of Experimental Biology http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Journal of Experimental Biology The Company of Biologists

Thin-blooded icefish relocate carbonic anhydrase to gill

Kathryn, Knight,
Journal of Experimental Biology , Volume 221 (22) – Nov 15, 2018
Download PDF
1 page

Loading next page...
 
/lp/the-company-of-biologists/thin-blooded-icefish-relocate-carbonic-anhydrase-to-gill-0157X0f8fj

References (1)

Publisher
The Company of Biologists
Copyright
© 2021 The Company of Biologists. All rights reserved.
ISSN
0022-0949
eISSN
1477-9145
DOI
10.1242/jeb.193680
Publisher site
See Article on Publisher Site

Abstract

© 2018. Published by The Company of Biologists Ltd | Journal of Experimental Biology (2018) 221, jeb193680. doi:10.1242/jeb.193680 INSIDE JEB gas into bicarbonate. The pH decreased rapidly, confirming that the enzyme is located on blood vessel cell membranes. And when Jonathan Wilson stained the cell membranes with a series of specialised dyes that could only bind to molecules of carbonic anhydrase, he found one form of the enzyme (carbonic anhydrase 4) attached to the membranes lining the inner surface of the gill blood vessels. To confirm the presence of the enzyme, Harter and David Metzger then collected RNA from the fish’s gills, eventually identifying an mRNA molecule that could be translated to produce the carbonic anhydrase 4 enzyme. However, when the team searched for carbonic anhydrase proteins in the gills of a close relative, Notothenia rossii, which has retained its red blood cells despite sharing C. gunnari’s icy waters, they A Champsocephalus gunnari icefish. Photo credit: Michael Axelsson. found none. Few animals can justifiably be called ‘thin Reasoning that it might be might be So, it seems that icefish have relocated blooded’, but Antarctic icefish genuinely situated on the inner surface of gill blood carbonic anhydrase to their gills to are. They lack the brightly pigmented vessels, Harter, Colin Brauner and their overcome the difficulties of carbon red blood cells that usually carry oxygen international team of collaborators began dioxide disposal after trading in their red around the body, although the blood is searching for the elusive enzyme in the blood cells. But they suspect that red- still capable of transporting oxygen to gills of Champsocephalus gunnari blooded fish are unlikely to follow their tissues thanks to the high solubility icefish. their apparently ‘bloodless’ cousin’s of the gas in the frigid Antarctic waters. convenient example, as the enzyme could But the fish face another problem. In most Although Harter was unable to visit drastically disturb the delicate balance bony fish, waste carbon dioxide is carried Antarctica himself, he was fortunate that allows their red blood cells to keep in the blood to the gills in the form of that Kristin O’Brien from University hold of their oxygen cargo when bicarbonate, where it is converted back of Alaska Fairbanks, USA, and Lisa exercising hard. into carbon dioxide in red blood cells by Crockett from Ohio University, USA, sent 10.1242/jeb.193680 an enzyme known as carbonic anhydrase, C. gunnari that they had caught during the before it is exhaled. ‘However this 2015 Antarctic field season. After the fish Harter, T. S., Sackville, M., Wilson, J. M., Metzger, D. C. H., Egginton, S., Esbaugh, A. J., Farrell, strategy is impossible in icefishes, which arrived, he cautiously isolated the outer A. P. and Brauner, C. J. (2018). A solution to have lost red blood cells’, says Till Harter membrane from the cells lining the inside Nature’s haemoglobin knockout: a plasma- from the University of British Columbia, of the gill blood vessels before bathing accessible carbonic anhydrase catalyses CO excretion in Antarctic icefish gills. J. Exp. Biol. Canada. While there is some evidence it in water saturated with CO and 221, jeb190918. that the essential bicarbonate converting measuring how the pH changed – in the protein is harboured somewhere in the hope that any carbonic anhydrase present Kathryn Knight gills, the precise location was not clear. on the membrane surface may convert the [email protected] Inside JEB highlights the key developments in Journal of Experimental Biology. Written by science journalists, each short report gives the inside view of the science in JEB. Journal of Experimental Biology

Journal

Journal of Experimental Biology – The Company of Biologists

Published: Nov 15, 2018

There are no references for this article.