caa a22 4500 378853139 CHVBK 20180305123328.0 cr unu---uuuuu 161128e20030820xx s 000 0 eng 10.1515/BC.2003.126 doi (NATIONALLICENCE)gruyter-10.1515/BC.2003.126 Differential Haemoglobin Gene Expression in the Crustacean Daphnia magna Exposed to Different Oxygen Partial Pressures [Elektronische Daten] [B. Zeis, B. Becher, T. Goldmann, R. Clark, E. Vollmer, B. Bölke, I. Bredebusch, T. Lamkemeyer, O. Pinkhaus, R. Pirow, R. J. Paul] The quantity and quality of the haemoglobin (Hb) of Daphnia magna is related to oxygen partial pressure in the water. Both the dynamics of hypoxia-induced Hb gene transcription, as well as Hb properties in animals incubated long-term at hyperoxia, normoxia and hypoxia, were investigated. Examination of Hb gene (dhb1-dhb3) transcription showed the expression of dhb2 and especially dhb3 to increase markedly approximately one hour after the onset of hypoxia, whereas dhb1 was expressed more or less constitutively. At an incubation close to anoxia, an onset of dhb3 transcription was found already after two minutes. In longterm incubated animals, concentration and oxygen affinity of Hb were lower at higher oxygen partial pressures. With decreasing oxygen availability, the subunit composition of Hb macromolecules changed. The share of the dhb2-encoded subunit, DHbF, increased already during moderate hypoxia. The increase of dhb3 mRNA (encoding DHbC) may be related to a transient increase of DHbC in the first days of hypoxia and/or to an additional coding of dhb3 for DHbD. The rise of DHbD, and particularly DHbA, only at severe hypoxia coincided with the increase of Hb oxygen affinity. The dhb1-encoded subunits DHbB and DHbE showed either a relatively moderate increase or even a decrease in concentration at hypoxia. In small animals with restricted homeostasis capabilities such as Daphnia, adaptation of the protein equipment seems to be a more effective strategy than allosteric modulator control. Copyright © 2003 by Walter de Gruyter GmbH & Co. KG Biochemistry nationallicence Molecular biology nationallicence Cellular biology nationallicence Zeis B. aut Becher B. aut Goldmann T. aut Clark R. aut Vollmer E. aut Bölke B. aut Bredebusch I. aut Lamkemeyer T. aut Pinkhaus O. aut Pirow R. aut Paul R. J. aut Biological Chemistry Walter de Gruyter 384/8(2003-08-20), 1133-1145 1431-6730 384:8<1133 2003 384 bchm https://doi.org/10.1515/BC.2003.126 text/html Onlinezugriff via DOI 1 research article jats NATIONALLICENCE 856 40 https://doi.org/10.1515/BC.2003.126 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Zeis B. aut NATIONALLICENCE 700 1- Becher B. aut NATIONALLICENCE 700 1- Goldmann T. aut NATIONALLICENCE 700 1- Clark R. aut NATIONALLICENCE 700 1- Vollmer E. aut NATIONALLICENCE 700 1- Bölke B. aut NATIONALLICENCE 700 1- Bredebusch I. aut NATIONALLICENCE 700 1- Lamkemeyer T. aut NATIONALLICENCE 700 1- Pinkhaus O. aut NATIONALLICENCE 700 1- Pirow R. aut NATIONALLICENCE 700 1- Paul R. J. aut NATIONALLICENCE 773 0- Biological Chemistry Walter de Gruyter 384/8(2003-08-20), 1133-1145 1431-6730 384:8<1133 2003 384 bchm CC0 http://creativecommons.org/publicdomain/zero/1.0 nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-gruyter