Role and induction of 2,3-bisphosphoglycerate synthase

Molecular and Cellular Biochemistry - 2,3-Bisphosphoglycerate accumulates in mammalian erythrocytes, where it facilitates the supply of oxygen to the tissues by binding to hemoglobin. Regulatory...     

Polyribosome disaggregation and cell-free protein synthesis in preparations from cerebral cortex of hyperphenylalaninemic rats

Abstract— Seven-day-old rats were injected intraperitoneally with l -phenylalanine (1 g/kg) and the time course of brain polyribosome disaggregation and changes in brain levels of phenylalanine, tryptophan and tyrosine were determined. Disaggregation of brain polyribosomes preceded the increase in levels of phenylalanine in brain, and followed the same time course as depletion of tryptophan from brain. The effects of several metabolites of phenylalanine (which are formed in phenylketonuria) on protein synthesis in vitro was determined for brain and liver systems. None of the compounds tested was inhibitory at concentrations below 10 mM and in all cases hepatic protein synthesis was more sensitive to inhibition than was the corresponding system from brain. Ribosomal dimers, formed in brain after injection of phenylalanine, were incapable of supporting high levels of protein synthesis in vitro, a finding that suggested that the inhibition of protein synthesis in vitro in cell-free systems of brain tissue after injection of phenylalanine into young rats was mediated by disaggregation of brain polyribosomes associated with tryptophan deficiency in brain.     

Inhibition of Thiamine Pyrophosphate Utilization by Thiamine or Its Monophosphate in Escherichia coli

The growth of a thiamine pyrophosphate auxotroph of Escherichi coli was inhibited by either thiamine or thiamine monophosphate, and the growth of a thiamine monophosphate auxotroph was inhibited by thiamine. The thiamine pyrophosphate-dependent oxidation of pyruvate was inhibited by thiamine with whole cells of the thiamine pyrophosphate auxotroph but not with cell extracts prepared from the same organism. In addition, the thiamine pyrophosphate uptake of the thiamine pyrophosphate auxotroph was inhibited by either thiamine or thiamine monophosphate. Although the thiamine pyrophosphate uptake of a revertant, selected for prototrophy from the thiamine monophosphate auxotroph, was inhibited by thiamine to an extent comparable to that observed with the thiamine monophosphate auxotroph, its growth was no longer inhibited by thiamine. A possible mechanism for the inhibition by thiamine and thiamine monophosphate in the utilization of thiamine pyrophosphate is discussed.     

Adenine-dependent growth of marine yeast,Rhodotorula glutinis var.salinaria under sodium chloride-hypertonic condition

Nitrate and ammonium were shown to alter the growth ofRhodotorula glutinis var.salinaria in saline and non-saline media. In saline medium in which ammonium was the sole nitrogen source, ammonium inhibited growth in the presence of molybdate ions. Detailed comparisons of the growth in saline and non-saline media when nitrate was supplemented in the presence of molybdate ions showed that differences in utilizability of purine bases of nucleic acid were responsible for the differences in growth,i.e. adenine increased the growth in such saline medium, but decreased it in non-saline medium. There was not such a specific requirement for adenine in saline medium in the presence of molybdate ions when nitrate was substituted for ammonium as the sole nitrogen source. It was suggested that adenine might provide the necessary skeleton of nucleic acid for serving nitrate reduction in saline medium.     

Electrocardiographic studies in the Japanese monkey (Macaca fuscata) with special reference to the effect of anesthesia with barbiturates

The electrocardiograms of 157 healthy Japanese monkeys (Macaca fuscata), covering a wide range of ages in both sexes, were recorded under light pentobarbital (Nembutal) anesthesia. Although results were generally similar to those reported for other macaque species, some quantitative differences were observed.The heart rate was about 160 per minute in all monkeys examined; the P-Q interval was 0.11±0.06 sec.; the duration of QRS was 0.04±0.01 sec.; the Q-T interval was 0.24±0.06 sec. The mean axis of QRS was +59° and the pattern of the QRS complex was qR type in most cases.The comparison with the human electrocardiogram shows that the heart rate ofM. fuscata is about twice that of man, while the P-Q, QRS, and Q-T intervals were about one-half of those found in human subjects. In the monkey, however, the P wave was sharp and the T wave flat.In order to estimate the effect of anesthesia on the electrocardiogram, the records of several monkeys before, during, and after intravenous administration of barbiturates were compared. Although some animals showed extrasystoles after barbiturate was administered, generally no essential changes were noted in the records, except for the retardation of the rate and proportional prolongation of intervals.This work was presented at the 10th Annual Meeting of the Primate Research Association held in Inuyama, March 13, 1966.