spacer gif spacer gif spacer gif spacer gif spacer gif
QUICK SEARCH:   [advanced]


spacer gif
     Home     Help     Feedback     Subscriptions     Archive     Search     Table of Contents    

First published online September 15, 2004
Journal of Experimental Biology 207, iii (2004)
Copyright © 2004 The Company of Biologists Limited
doi: 10.1242/jeb.01271
This Article
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Email this article to a friend
Right arrow Related articles in JEB
Right arrow Similar articles in this journal
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow reprints & permissions
Citing Articles
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Phillips, K.
Right arrow Search for Related Content
PubMed
Right arrow Articles by Phillips, K.

Inside JEB

PROCESSING A LIQUID LUNCH

Kathryn Phillips

kathryn{at}biologists.com


Rhodnius prolixus doesn't dine often, but when it does, it really goes to town. Consuming fresh blood meals in excess of ten times its unfed mass, the insects really gorge. But their extravagant tastes come at an enormous metabolic cost; the insect must rid itself of huge volumes of fluid before benefiting from its diet. To counteract the dilute meal, Mike O'Donnell explains that Rhodnius produces hyposmotic urine by secreting sodium, potassium and chloride ions into the Malpighian tubule through a cotransporter. Apparently most cotransporters in this class only function if all three ions are present. But O'Donnell adds that Rhodnius reabsorbs most of the valuable potassium ions further along the Malpighian tubule, and the Rhodnius cotransporter appears to function even when potassium is absent. Puzzled, O'Donnell, Juan Ianowski and Robert Christensen were curious to resolve the apparent contradiction (p. 3707).

Measuring the tubule's secretion rates in the presence of potassium while they raised the sodium levels, the team found that potassium transport became inhibited as the sodium levels rose; sodium transport was replacing potassium transport. So instead of continually losing potassium, the insect retained the precious ion while increasing its sodium and chloride losses. The team suspect that this unusual cotransporter behaviour allows Rhodnius to produce large volumes of dilute salty urine, while retaining potassium, as it processes a liquid lunch.

References

Ianowski, J. P., Christensen, R. J. and O'Donnell, M. J. (2004). Na+ competes with K+ in bumetanide-sensitive transport by Malpighian tubules of Rhodnius prolixus.J. Exp. Biol. 207,3707 -3716.[Abstract/Free Full Text]


Related articles in JEB:

Na+ competes with K+ in bumetanide-sensitive transport by Malpighian tubules of Rhodnius prolixus
Juan P. Ianowski, Robert J. Christensen, and Michael J. O'Donnell
JEB 2004 207: 3707-3716. [Abstract] [Full Text]  




This Article
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Email this article to a friend
Right arrow Related articles in JEB
Right arrow Similar articles in this journal
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow reprints & permissions
Citing Articles
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Phillips, K.
Right arrow Search for Related Content
PubMed
Right arrow Articles by Phillips, K.