In vivo-Untersuchungen �ber den Glucose-Abbau beiArenicola marina (Annelida, Polychaeta)

The Pasteur effect in facultative anaerobic metazoa

The existence and the regulatory mechanisms of the Pasteur effect in facultative anaerobic metazoa are discussed. There are three reasons for the controversy surrounding this phenomenon. 1) The different definitions of the Pasteur effect, 2) the antagonistic effect of metabolic depression and its species specific response to hypoxia, as well as 3) the laboratory-specific differences in the experimental procedures for analyzing the Pasteur effect and its regulation. This review aims to clarify the confusion about the existence of the Pasteur effect in facultative anaerobic metazoa and to offer possible molecular mechanisms.

Direct calorimetry in ecological energetics. Long term monitoring of aquatic animals

The measurement of heat production represents the most general approach to the estimation of energy flow through biological systems. While aerobic energy metabolism is most conveniently studied by polarographic oxygen determination, direct calorimetry presents the only unspecific method for quantitative comparison of aerobic and anoxic metabolism in animals. In flow calorimeters constant experimental conditions may be controlled for practically unlimited periods of time, and transitions of the environmental regime may be repeatedly performed during one experiment. The merits of a direct calorimetric flow system are demonstrated in case studies of anoxic and aerobic animal metabolism and discussed in the context of current biochemical and ecophysiological concepts.

Glutamate dehydrogenases from tissues of the ribbed mussel Modiolus demissus: ADP activation and possible physiological significance

Glutamate dehydrogenase (E.C. 14.1.3) was localized in the mitochondria from heart, gill, mantle and hepatopancreas of this euryhaline bivalve mollusc. Activity levels were low (0.1-0.4 mumoles/min/g wet weight) in all tissues when assayed in the glutamate forming direction. Partially purified gill mitochondrial GDH was most active at pH 8.5. The rate in the glutamate deaminating direction was 10-20% of the rate in the glutamate forming direction. ADP at apparent Ka concentrations of micrometer (glutamate formation) and 170 micrometer (glutamate deamination) enhanced GDH activity, 8- and 4-fold respectively. GDH, in vivo, is probably in the activated form and appears to function in glutamate synthesis rather than ammonia formation. However, based on the low activities obtained, the role of GDH in salinity induced amino acid synthesis seems minimal.

Anaerobic metabolism of the common cockle, Cardium edule. I.--The utilization of glycogen and accumulation of multiple end products

1. Concentrations of glycogen and of key metabolites have been measured in Cardium edule during aerobic and anaerobic incubation. 2. After 15 hours of anoxia only a slight carbohydrate consumption was found in the whole animal, whereas a decrease in glycogen level seemed evident in the separated adductor muscle. 3. The main end products of the anaerobic carbohydrate breakdown are succinate and alanine which account for 40% and 30% respectively of all accumulated compounds. 4. The concentrations of L-lactate and octopine also increase after 15 hours anaerobic condition, but both are only of minor importance as end products. 5. Propionate is not detectable in the control groups, but accumulates a little during anaerobiosis. The two possible reasons for this low production have been discussed.