1. The pathways of glutamate formation from glucose and acetate were compared in Brevibacterium flavum No. 2247 (ATCC No. 14067) and Micrococcus glutamicus No. 534 (ATCC No. 13032) using biotin-poor media. 2. B. flavum and M. glutamicus produced large amounts of glutamate from glucose in biotin-poor media, and resting cells of both strains produced α-ketoglutarate, or glutamate in the presence of ammonium salt, from glucose with a yield of 45-55%. 3. Oxidative metabolism of glucose in resting cells of both M. glutamicus and B. flavum was inhibited by arsenite, and 1 mole of pyruvate was formed from 1 mole of glucose, accompanied by 1 mole of O2 uptake and 1 mole of CO2 evolution. 4. Labeled pyruvate was formed from glucose-1-, -6-, and -U-14C in the presence of arsenite by resting cells of M. glutamicus. From the 294 ÔTSUKA, MIYAJIMA and SHIIO Vol. 11 relative specific activity of pyruvate to substrate glucose and from distribution of 14C in pyruvate molecule, it was concluded that glucose was metabolized aerobically by both the EM and HMP pathways in the approximate ratio 85:15. 5. It was confirmed that glutamate was formed from acetate by resting cells of B. flavum, while acetate was completely oxidized to carbon dioxide by resting cells of M. glutamicus. Acetate oxidation of both strains was markedly inhibited by 5×10-2M of monofluoroacetate.
1. When Brevibacterium flavum No. 2247 (ATCC No. 14067) or Micrococcus glutamicus No. 534 (ATCC No. 13032) was cultured in biotin-rich medium, L-glutamate was not formed from glucose by either resting or growing cells, the resting cells of both strains oxidized glucose completely to carbon dioxide. 2. Enzyme activities which seem most closely related to glutamate formation did not change significantly with biotin concentration in the culture medium. An exception was isocitrate lyase activity in M. glutamicus. This enzyme was highly active in cell-free extracts prepared from biotin-rich cells, but hardly observed in cell-free extracts prepared from biotin-poor cells. 3. Marked differences of cellular permeability to glutamate between biotin-rich and biotin-poor cells of both strains were demonstrated with L-aspartate-α-ketoglutarate transaminase activity and with release of intracellular free glutamate on washing. 4. These results suggest that the "permeability hypothesis" proposed previously with regard to the effect of biotin on the extracellular formation of glutamate would be also applicable in the case of M. glutamicus.
A polyol was isolated from the conidia of Aspergillus oryzae and identified as glycerol. A NADP specific glycerol dehydrogenase (glycerol:NADP oxidoreductase) was found in the conidia; substrate specificities, pH optimum, Michaelis constants, the effect of inhibitors and stoichiometry were studied. Kinetic studies suggested that the main reaction by the enzyme was formation of glycerol. Glycerol dehydrogenase might play a role in the biosynthesis of glycerol from dihydroxyacetone or glyceraldehyde which was probably from triosephosphate by the action of phosphatases. Isotopic experiments and assays of glycerol in the germinating conidia agreed with these results.
The stimulative effect of succinate on cellulose decomposition and cellulase formation was studied with Ruminococcus flavefaciens and Ruminococcusalbus. The decomposition of cellulose by ruminal bacterial fraction was also stimulated by succinate. Glucose grown cells of R. albus and Bacteroides succinogenes which had no detectable cellulase activity formed the enzyme when the cells were incubated with succinate. These results suggest that the succinate effect is a general phenomenon in rumen bacteria.
A change in proteolytic activity in relation to the cell cycle was studied using synchronized cultures of Escherichia coli. Activities of three enzymes, protease, leucine aminopeptidase and glycylglycine dipeptidase, showed rhythmic variations in the cell cycle of the bacteria. The highest enzyme activities were found during the fission period and the lowest in the interdivision phase. The physiological significance of these observations is discussed.
Determinative studies were carried out with yeasts isolated from oil-brines and related materials obtained from oil-fields in Japan, and the following species were identified: Sporobolomyces japonica, new species, 1 strain; Rhodotorula rubra (Demme) Lodder, 25 strains; and Rh. glutinis (Fres.) Harrison var. rufusa, new variety, 7 strains. The species found in oil-brines differ from those of soil, and all isolates were the so-called red yeast which produce carotenoid pigments.
(1) Inosine-producing mutants derived from Bacillus subtilis strains had a common characteristic of converting exogenously added hypoxanthine to inosine in high yields. Investigations on activities of the "salvage" synthesis and of degradation of inosine revealed that differences in the latter activities might mainly be related to differences of the former reaction. (2) No. 11023, an inosine-producing mutant, degraded inosine to hypoxanthine 1/3-1/5 as much as the original strain. However, the strong activity of "salvage" synthesis seemed to completely suppress this degrading activity in inosine fermentation. Therefore, the "salvage" synthetic activity was thought essential for characterization as a typical inosine-producing mutant. (3) On the "salvage" synthesis and de novo formation of inosine some interesting relationships were observed. Total amount of inosln ("salvage" synthesized plus de novo formed) was always far greater than that by denovo formation. De novo formation was much influenced by the culture medium, especially by ammonium and phosphate ion concentrations, but total inosine was nearly equal under these different conditions. (4) "Salvage" syntheses of ribonucleosides from several kinds of bases by the original strain and many mutants were compared. Some interconversions of bases and nucleosides as well as "salvage" syntheses were observed. Both inosine- and xanthosine-producing mutants were capable of forming inosine and xanthosine from several kinds of purine bases, respectively.
A comparative study of the organic acid productivities of respiration-competent ("normal") and respiration-deficient (RD) strains of brewers' yeasts (Saccharomyces carlsbergensis) was made using a chemically defined medium containing 5% glucose. After growing for 6 days, lactic and an unknown acids were mainly accumulated by RD-mutants, while acetic, succinic and lactic acids were the major acids accumulated by the "normal" strains. The unknown acid was then isolated in a pure form by repeated silica gel chromatography and was identified as (-)-citramalic acid by elemental analysis, IR and NMR spectra, and rotation measurement. (-)-Citramalic acid was also accumulated by RD-mutants in other media, and the ratio of (-)-citramalic acid to the total amount of organic acids produced was almost constant (32-39%), even when the amount of citramalic acid increased by increasing glucose concentration or by the addition of calcium carbonate to the media.
Edited and published by : Applied Microbiology, Molecular and Cellular Biosciences Research Foundation/Center for Academic Publications Japan Produced and listed by : TERRAPUB, Center for Academic Publications Japan/Shobi Printing Co., Ltd. (-Vol.60,No12), Center for Academic Publications Japan/InternationalAcademic Printing Co., Ltd.(-Vol.54,No1)