Organ specific changes in energy metabolism due to anaerobiosis in the sea mussel Mytilus edulis (L.)

1. 1. Anaerobic energy metabolism was investigated in different organs of Mytilus edulis and the whole animal. 2. 2. Succinate accumulates to high levels in most organs but remains low in the hemolymph. 3. 3. After 16 hours propionate accumulation is observed in all organs. Experimental evidence is not sufficient yet to point out organs that produce more propionate than others. 4. 4. Acetate is a minor end product. 5. 5. Acetate and propionate are found in the hemolymph in amounts equal to those in the organs. 6. 6. Animals incubated in oxygen-free seawater accumulate more end products than animals exposed to air, in the form of volatile fatty acids that are excreted into the incubation water. 7. 7. Alanine and glutamine increase in the posterior adductor muscle. Aspartate decreases in the total animal, posterior adductor muscle and gills, while in the hemolymph decrease in alanine, asparagine, serine, threonine and proline are observed

Seasonal variations in biochemical composition of mytilus edulis with reference to energy metabolism and gametogenesis

1. 1. Seasonal changes in biochemical composition in relation to energy metabolism and to gametogenesis were studied in Mytilus edulis for nearly one and a half year. 2. 2. During the whole experimental period animals were selected from samples of the same musselbed in the Dutch Wadden Sea at intervals of about three weeks. 3. 3. The biochemical composition of total tissues and different organs was analyzed. In growing mussels a gradual increase of protein, glycogen and lipid contents was observed from spring to autumn. From November to next April the protein and glycogen content declined, whereas the lipid content remained rather constant until spawning. The observed changes are discussed in relation to environmental parameters as temperature, salinity and nutrient levels, as well as to energy production and gametogenesis. 4. 4. Hardly no seasonal variations were found in the total free amino acid concentrations from both the total tissues and different organs. However, the individual amino acids showed clear seasonal changes in all tissues investigated. The greatest fluctuations were found for taurine and glycine. These amino acids showed an inverse relation to each other. 5. 5. Seasonal changes in the accumulation of end products of anaerobic metabolism and in the composition of the free amino acid pool were found in groups of mussels exposed to air for 48 h. The observed variations in propionate and alanine accumulation as well as other compiunds involved in anaerobic metabolism are discussed in relation to temperature and salinity

The influence of seasonal changes on energy metabolism in Mytilus edulise (L.).—III. Anaerobic energy metabolism

1. 1. Seasonal changes in the accumulation of end products after 48 hr of exposure to air and in the composition of the free amino acid pool were studied in Mytilus edulis. 2. 2. The accumulation levels of succinate and acetate showed only weak seasonal changes. 3. 3. Conversion of succinate to propionate was high in summer and virtually zero in winter 4. 4. Alanine and most other free amino acids were present in relatively high concentrations in summer and early autumn and reached minimal values in winter and early spring. 5. 5. Exceptions were glutamate, aspartate and taurine, which showed hardly an season related changes and glycine, which changed inversely to the majority of the free amino acids. 6. 6. The anaerobic formation of alanine was inversely proportional to the endogenous concentration. 7. 7. The only other free amino acids affected by anaerobiosis were glutamate and aspartate, which respectively increased and decreased under these conditions

Effects of PCB 126 and cadmium on the anaerobic metabolism of the mussel Mytilus edulis L

Exposure of mussels to PCB 126 and/or cadmium resulted in elevated anaerobic metabolic activity during 48 hr of aerial exposure. In mussels exposed to PCB 126 or cadmium this was achieved by an increased opine production. The largest increase was observed in PCB exposed mussels. In mussels that were exposed to PCB 126 and cadmium simultaneously the production of both succinate and opines had increased. Simultaneous exposure to PCB 126 and cadmium had a more negative effect on the aerial survival time than exposure to PCB 126 alone, whereas exposure to cadmium alone did not have a significant effect on the tolerance to aerial exposure. [KEYWORDS: anaerobic end products; opines; contaminants; succinate; survival in air Liquid-chromatography; energy-metabolism; extracts; alanopine; separation; strombine; mollusks; toxicity; hypoxia; stress]