Expression of Pyruvate Kinase, Malate and Octopine Dehydrogenase Genes in the Gills of the Mediterranean Mussel Mytilus galloprovincialis (Lamarck, 1819) under Conditions of Hypoxia and Reoxygenation

The effect of hypoxia on the level of expression of pyruvate kinase (PKM), octopine dehydrogenase (OcDH), and malate dehydrogenase (MDH) genes in the gill tissue of the Mediterranean mussel Mytilus galloprovincialis (L., 1819) was studied experimentally. The control group of mollusks was kept at 9-10 degrees C, and the oxygen level in the water was 8.5 mg O-2 L-1. The experimental levels were at 9-10 degrees C and 2.2 mg O-2 L-1. The exposure was 24 and 72 h. Some of the individuals were subsequently subjected to the reoxygenation procedure. Under conditions of hypoxia, the expression level of OcDH and MDH genes increased by three and two times, respectively (p < 0.05). At the same time, OcDH expression showed sensitivity to the oxygen content in the medium. Under the conditions of reoxygenation, the process was completely suppressed. The expression of the PKM gene, on the contrary, did not depend on hypoxic effects and remained at the level of the control values.