Metabolism of Glutamate in Purple Nonsulfur Bacteria Participation of Vitamin B12

Purple nonsulfur bacteria, Rhodospirillum rubrum and Rhodopseudomonas spheroides were found to possess coenzyme B₁₂-dependent glutamate mutase activity. Cell-free extracts of these bacteria grown on Co²⁺-containing media catalyzed the conversion of glutamate to β-methylaspartate and further to mesaconate. The activity of the cell-free extracts of these organisms cultivated on Co²⁺-deficient media was markedly lower than that of the normal cells. Addition of coenzyme B₁₂ to the former reaction mixture enhanced the mesaconate formation via β-methylaspartate. These results indicate the involvement of coenzyme Independent glutamate mutase of these bacteria in the dissimilation of glutamate to acetyl-CoA and pyruvate through the following pathway.

glutamate→β→methylaspartate→mesaconate→citramalate→→acetyl-CoA, pyruvate On the other hand, a greater part of glutamate was converted to α-hydroxyglutarate and succinate with the cell-free extracts of these photosynthetic bacteria. This fact, taking account of the presence of propionyl-CoA carboxylase in these bacteria, implies the participation of coenzyme B₁₂-dependent (R)-methylmalonyl-CoA mutase in the formation of succinate via the following route.

glutamate→α-ketoglutarate→α-hydroxyglutarate→propionate→propionyl-CoA→(S)-methylmalonyl-CoA→(R)-methylmalonyl-CoA→succinyl-CoA     

Effects of Phosphatidylcholine or Ergosteryl Oleate on Physiological Properties of Saccharomyces sake

Chromatographically homogeneous phosphatidylcholine identified by thin-layer chromatography on silica gel G was isolated from mycelia of Aspergillus oryzae or egg yolk by a combination of alumina and silicic acid column chromatography. Although the 2-position in both Asp. oryzae- and egg yolk-phosphatidylcholine was occupied nearly exclusively by unsaturated fatty acids, significant proportions of unsaturated fatty acids were also found in the 1 -position of Asp. oryzae-phosphatidylcholine. In nitrogen gas-sparging anaerobic culture of Saccharomvces sake Kyokai No. 7, supplementing the basal synthetic medium with phosphatidylcholine enhanced the yeast growth and fermentative activity, whereas adding ergosteryl oleate enhanced alcohol-endurability. Supplementation with both phosphatidylcholine and ergosteryl oleate promoted the yeast growth, fermentative activity and alcohol-endurability of cells.     

Chitin Coated Cellulose as an Adsorbent of lysozyme like Enzymes Preparation and Properties

As a new adsorbent of lysozyme-like enzymes, chitin coated (CC-)cellulose was prepared. CC-cellulose was stable and had good flow properties for use in column chromatography. Affinity chromatography with CC-cellulose showed that 3~5 mg of lysozyme/ml resin was adsorbed specifically and desorbed quantitatively under mild conditions. The utilities of the method of affinity chromatography with CC-cellulose are discussed.     

Cell Structure of Yeasts Grown Anaerobically in Aspergillus orpzae-Proteolipid-supplemented Media

Effects of Aspergillus oryzae-proteolipid (PL) on the formation of high concentrations of alcohol, more than 20% as in sake brewing, have been studied. Electron microscopy revealed that there were no vacuoles but many lipid deposits in cytoplasm of the alcoholtolerant cells of Saccharomyces sake Kyokai No. 7, which were obtained by the anaerobic culture supplemented with PL. Sphaeroplasts from the alcohol-tolerant cells were stable in 20% alcohol, whereas those from the untolerant cells grown anaerobically in the PL-unsupplemented media were ruptured. The cell membrane became alcohol-endurable in the anaerobic cultures with PL. Synthetic phospholipid promoted yeast growth and the fermentative activity, whereas a small amount of sterol ester enhanced the alcohoi-endurability. The supplementation of both lipids anaerobically induced physiological properties characteristic of the alcohol-tolerant cells.     

Isolation and Structure of Neoannonin,a Novel Insecticidal Compound from the Seeds of Annona squamosa

Two insecticidal compounds were isolated from the seeds of Annona squamosa. One was identified as annonin (squamocin) and the other was characterized as a novel dihydroxy-bistetrahydrofuran fatty acid lactone (acetogenin) with 35 carbons. These two compounds were toxic to eggs, larvae and adults of the fruitfly.     

The Chemistry of Ilexol. I.

Ilexol, a new triterpenoid alcohol isolated from the barks of several species of the Genus Ilex, has now been oxidized with chromium trioxide to yield a ketone, designated as ilexone of C₃₀H₄₈O, m.p. 239.5–240.5°, and – 68.74°, which gives oxirne of m. p. 256.5–257.5°, 2,4-dinitrophenylhydrazone of m.p. 260–261°, and positive Zimmermann test.

On reduction with sodium and ethanol as well as with lithium aluminum hydride, it has been shown that ilexone is regenerated to yield an alcohol proved to be identical with natural ilexol.

On reduction according to the procedure of Huang-Minion, ilexone has been shown to yield an oxygen-free compound, designated as ilexene of C₃₀H₅₀, and m.p. 241–242°.

It seems most likely that ilexol might be a triterpenoid alcohol of C₃₀H₄₉OH, an alcoholic hydroxyl group of which is secondary in nature, and moreover attached at C–3 in its molecule.     

Essential Role of Aspartokinase in L-Threonine Production by Escherichia coli W Mutants

We previously constructed an l-threonine-producing strain of E. coli W, KY8280, which is an Ile⁺ revertant of KY8279 which requires l-methionine, a,£-diaminopimelic acid and l-isoleucine [H. Kase et al., Agric. Biol. Chem., 35, 2089 (1971)]. From KY8280, another l-threonine-hyperproducing strain, KY8366, was obtained as an α-amino-β-hydroxy valeric acid (AHV, a threonine analog)-resistant mutant. Enzymatic analysis revealed that KY8280 constitutively expressed 8-fold higher l-threonine-sensitive aspartokinase I activity than KY8279. In addition, KY8366 constitutively expressed 13-fold higher l-lysine-sensitive aspartokinase III activity than KY8280. Such elevated levels of aspartokinases may contribute to the hyperproduction of l-threonine by these mutant strains. KY8366 produced 28 mg/ml of l-threonine in a culture medium fed with 12% glucose.     

The Heterogeneity of the 7S Soybean Protein by Sepharose Gel Chromatography and Disc Gel Electrophoresis

Two kinds of N-acetylmuramidase, M-1 and M-2 enzymes, that were isolated from the cultural broth of Stm. globisporus 1829, were remarkably different in amino acid composition, immunological properties and modes of lytic action from each other. The M-1 enzyme was composed of 186 amino acid residues of which two moles were of half cystine, while the M-2 enzyme was composed of 99 amino acid residues with no cysteine. The hydrolyzing action of the M-2 enzyme was suppressed by the presence of an O-acetyl group on muramic acid residues in the peptidoglycan moiety, while that of the M-l enzyme was independent of the presence of O-acetyl groups. However, the hydrolyzing activity of both enzymes was enhanced when some muramic acid residues were substituted with stem peptides containing alanine, isoglutamine and lysine.