LACTIC AND Α-Glycerophosphate DEHYDROGENASES IN INSECTS

Abstract

Different tissues, especially muscles, from insects belonging to various groups were extracted and studied for their lactic dehydrogenase (LDH) and α-glycerophosphate dehydrogenase (GDH I) activities from the comparative point of view. In all cases assays of flight muscle extracts showed extremely low values of LDH activity whereas the GDH activities were surprisingly high. The activities in leg muscles were generally lower. In some insects, however, a very active LDH was found; in these cases the GDH activity seemed to be decreased. GDH I was rather active in the fat bodies. The presence of particulate glycerophosphate dehydrogenase (GDH II) was also demonstrated in insect muscles. These results were interpreted as indicating a system by which there is accomplished immediate and direct breakdown of metabolites to supply large amounts of energy during flight and other activities without the accumulation of intermediate substances.

The control of tricarboxylate-cycle oxidations in blowfly flight muscle. The steady-state concentrations of coenzyme A, acetyl-coenzyme A and succinyl-coenzyme A in flight muscle and isolated mitochondria

“…CoA content rises immediately on the activation of respiration (state 3) but then appears to fall, as succinyl-CoA concentration increases. Extrapolation of these results to the situation in vivo is difficult because although the concentration of carnitine used was similar to that in the fly (Childress et al, 1967) o; acetyl-CoA, (Zebe & McShan, 1957;Chefurka, 1958). Inclusion of glycerol phosphate in the experiment (Fig.…”

Increased muscular volume and cuticular specialisations enhance jump velocity in solitarious compared with gregarious desert locusts,Schistocerca gregaria

“…10A). Jumping in grasshoppers is a metabolically costly activity, and in the first minute of repetitive jumping a substantial oxygen debt is incurred with a corresponding accumulation of lactate in the extensor tibiae muscle (Zebe and McShan, 1957;Gade, 1984;Harrison et al, 1991;Kirkton et al, 2005). Schistocerca americana, a closely related non-swarming species that shows limited phase change (Sword, 2003;Gotham and Song, 2013), undergoes a two-thirds decrease in its jumping rate during 5 min of sustained jumping (Kirkton and Harrison, 2006).…”

IMP-L3, a 20-hydroxyecdysone-responsive gene encodes Drosophila lactate dehydrogenase: Structural characterization and developmental studies

“…LDH occurs in insects where oxygen availability is limited, for example, in the aquatic larvae of Chironomus and of the waterbug Belostoma [Zebe and McShan, 1957], and in tissues such as the femoral ''jumping'' muscles of grasshoppers [Delbrü ck et al, 1959]. In the dipterans Drosophila melanogaster [Rechsteiner, 1970b] and Muscsa domesticus [Agatsuma et al, 1977] LDH activity levels are high during larval development and drop ten-fold in pupal and adult stages.…”