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Biomedical subjects

R Vilu

Publications and source records attributed to R Vilu.

3 recordsLinked to original sources

Role of adenine nucleotides in the regulation of bacterial energy metabolism: theoretical problems and experimental pitfalls.

The effect of growth rate on ATP pool and adenylate energy charge (EC) value of Escherichia coli has been studied in batch culture on different media (mu max varying from 0.1 h-1 to 1.2 h-2) and in continuous culture at dilution rates (D = mu) from 0.045 h-1 to 0.310 h-1. Within the limits of error both ATP pool and EC values did not change with alterations in the relative growth rate of E. coli. The effect of in vivo EC values on experimental errors in ATP, ADP and AMP measurements with the luciferin-luciferase method, and, subsequently, on measurements of different ratios between adenylates, as in the case of adenylate kinase in vivo equilibrium, is discussed.

Adenine Nucleotides

13C-NMR study of acetate assimilation in Thermoproteus neutrophilus.

Acetate assimilation into amino acids and the functioning of central biosynthetic pathways in the extremely thermophilic anaerobic archaebacterium Thermoproteus neutrophilus was investigated using 13C NMR as the method for determination of the labelling patterns. Acetate was assimilated via reductive carboxylation of acetyl-CoA to pyruvate and pyruvate conversion to phosphoenolpyruvate which was further carboxylated to oxaloacetate. 2-Oxoglutarate was mainly formed via citrate. However, the labelling patterns of glutamic acid and alanine were in agreement with the concurrent synthesis of about 15% 2-oxoglutarate and 5% pyruvate through the reductive citric acid cycle. A scrambling phenomenon occurring in aspartate and all amino acids derived through oxaloacetate was observed. The labelling patterns of amino acids were in agreement with their standard biosynthetic pathways, with two remarkable exceptions: isoleucine was synthesized via the citramalate pathway and lysine was synthesized via the 2-aminoadipate pathway which has previously been reported only in eukaryotic microorganisms.

Acetates