ISSN:
1432-136X
Keywords:
Birgus
;
Land crabs
;
Carbon dioxide
;
Carbonic anhydrase
;
Gills
;
Lungs
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Medicine
Notes:
Summary The activity of carbonic anhydrase (CA), which catalyses the equilibrium CO2⇋H++HCO 3 - , was investigated in various tissues implicated in the excretion of CO2 by Birgus latro. Carbonic anhydrase was detected in the water-soluble fraction of gill tissue but also occurred in association with lipids (membrane bound). This is consistent with a CO2 excretory role and an ion regulation function for the gills. In the lungs (branchial chamber lining) CA activity was found in the membrane bound fraction but was not detected in the soluble fraction, suggesting that the lung CA is not important for ion regulation. The specific CA activity of gill tissue homogenate (A=1.8±0.7·mg-1) was higher than that measured for lung homogenates (A=0.4±0.2·mg-1), but when the whole organ was considered the total CA activity in the lungs was not significantly different from total CA activity in the gills. In comparison to aquatic and amphibious crustaceans the specific activity of carbonic anhydrase in the lungs was high (∼25% cf. gill activity). This CA activity in the lungs could be correlated with significant CO2 excretion by the lungs. CA may be retained in the branchial tissue as an adjunct to ion reabsorption by the gills.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00300957
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