Citrate-synthase mRNA in relation to enzyme synthesis in division-synchronized Euglena cultures

Abstract

The regulation of citrate-synthase (EC 4.1.3.7) synthesis in division-synchronized cultures of Euglena gracilis Klebs strain z was investigated. Citrate-synthase activity increased approximately two fold at the end of the light phase and in early dark phase in phototrophic cells synchronized by a 14 h light-10 h dark regime. Anti-(citrate synthase) was used to demonstrate that this increase in activity resulted from an increase in citrate-synthase protein. The amount of polyadenylated RNA per aliquot of culture increased midway through the light phase (before DNA replication) and had doubled by the end of this phase. Anti-(citrate synthase) was used to detect precursor citrate synthase in translations of total polyadenylated RNA in rabbit reticulocyte lysates. Citratesynthase mRNA was found to be present in cells at each stage of a division cycle, so that a stagespecific production of this mRNA to coincide with an increase in enzyme protein is unlikely. It is suggested that a post-transcriptional control operates in the regulation of citrate-synthase synthesis.

Effect of l-glutamate on 2-oxoglutarate decarboxylase in Euglena gracilis

“…3) and immunoblot analysis (Fig. 4) indicate that the increase in 2-OG decarboxylase activity results from an increase in protein, as is the case for the increase in citrate synthase in regreening [7] and division-synchronized Euglena cells [15]. The increase in 2-OG decarboxylase and NADP+-linked SSA dehydrogenase activities after the addition of L-glutamate indicates that, as L-glutamate is accumulated in Euglena cells, both NADP+-linked SSA dehydrogenase and 2-OG decarboxylase are induced to assimilate the amino acid.…”

Aerobic‐interval exercise with blood flow restriction potentiates early markers of metabolic health in man

“…Compared to the other exercise sessions, BFR‐interval exercise evoked similar responses of the investigated mitochondrial genes, including CS , p53 , COXIV‐1 and COXIV‐2 . The finding that none of the sessions significantly changed the expression of these genes suggests that they are either under post‐transcriptional control, as shown in cell culture experiments for citrate synthase (CS) 54 or alternatively, that the time point of measurement (+3h post exercise) was not optimal for detecting changes at the mRNA level 55 . By contrast, the expression of both PGC‐1α2 and ‐1α3 was selectively increased by the BFR‐session.…”

Comparative molecular cell biology of phototrophic euglenids and parasitic trypanosomatids sheds light on the ancestor of Euglenozoa

“…The fraction of polysome‐associated LHCPII mRNA was the same in the dark when the synthesis of LHCPII precursor (pLHCPII) was low as in the light when the rate of pLHCPII synthesis had increased 50–100‐fold (Weiss et al, , ; Kishore & Schwartzbach, ). The photoinduction of the E. gracilis cytoplasmic localized enzymes ascorbate peroxidase and NADPH (reduced NADP + ) glutamate dehydrogenase, the mitochondrial enzymes fumarase and citrate synthase, the ethanol induction of fumarase and the glutamate induction of NADPH‐glutamate dehydrogenase occurs in the absence of a concomitant increase in mRNA levels (Cannons & Merrett, , ; Fayyaz‐Chaudhary, Cannons & Merrett, ; Parker, Javed & Merrett, ; Javed & Merrett, ; Rikin & Schwartzbach, ; Madhusudhan et al, ).…”