Gas Transfer System inAlvinella pompejana(Annelida Polychaeta, Terebellida): Functional Properties of Intracellular and Extracellular Hemoglobins
| Autor: | André Toulmond, Brian N. Green, Stéphane Hourdez, Marie-Cécile De Cian, François H. Lallier, Roy E. Weber |
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| Rok vydání: | 2000 |
| Předmět: |
biology
Physiology Chemistry Temperature Order (ring theory) Polychaeta Anatomy Hydrogen-Ion Concentration biology.organism_classification Adaptation Physiological Biochemistry Oxygen Hemoglobins Crystallography Gas transfer Digestive System Physiological Phenomena Extracellular Alvinella pompejana Animals Terebellida Animal Science and Zoology Hemoglobin Intracellular Hydrothermal vent |
| Zdroj: | Hourdez, S, Lallier, F H, De Cian, M C, Green, B N, Weber, R E & Toulmond, A 2000, ' Gas transfer system in Alvinella pompejana (Annelida polychaeta, Terebellida): functional properties of intracellular and extracellular hemoglobins ', Physiological and Biochemical Zoology, vol. 73, no. 3, pp. 365-73 . https://doi.org/10.1086/316755 |
| ISSN: | 1537-5293 1522-2152 |
| DOI: | 10.1086/316755 |
| Popis: | Alvinella pompejana is a tubicolous polychaete that dwells in the hottest part of the hydrothermal vent ecosystem in a highly variable mixture of vent (350 degrees C, anoxic, CO(2)- and sulfide-rich) and deep-sea (2 degrees C, mildly hypoxic) waters. This species has developed distinct-and specifically respiratory-adaptations to this challenging environment. An internal gas exchange system has recently been described, along with the report of an intracellular coelomic hemoglobin, in addition to the previously known extracellular vascular hemoglobin. This article reports the structure of coelomic hemoglobin and the functional properties of both hemoglobins in order to assess possible oxygen transfer. Coelomocytes contain a unique monomeric hemoglobin with a molecular weight of 14,810+/-1.5 Da, as determined by mass spectrometry. The functional properties of both hemoglobins are unexpectedly very similar under the same conditions of pH (6.1-8.2) and temperature (10 degrees -40 degrees C). The oxygen affinity of both proteins is relatively high (P50=0.66 Torr at 20 degrees C and pH 7), which facilitates oxygen uptake from the hypoxic environment. A strong Bohr effect (Phi ranging from -0.8 to -1.0) allows the release of oxygen to acidic tissues. Such similar properties imply a possible bidirectional transfer of oxygen between the two hemoglobins in the perioesophagal pouch, a mechanism that could moderate environmental variations of oxygen concentration and maintain brain oxygenation. |
| Databáze: | OpenAIRE |
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