Tsunetake Sugimori

Production of microbial neuraminidases induced by colominic acid

Abstract Microorganisms capable of producing neuraminidases were sought by using culture media containing colominic acid, a homopolymer of N -acetylneuraminic acid, as a sole source of carbon. Among 1000 microorganisms screened, neuraminidases with strong activity and wide specificity were obtained from the culture filtrate of Sporotrichum schenckii, Penicillium urticae, Streptomyces sp., and an unidentified bacterium B 3831-1.

On the Metabolism of Organic Acids by Clostridium acetobutylicum: Part III. Purification and Properties of RacemiasePart IV. Mechanism of Racemiase ActionPart V. Further Studies on the Formation of RacemiasePart VI. Metabolism of Crotonic AcidPart VII. Reduction of Crotonic Acid

Racemiase, an enzyme which catalyzed racemization of lactic acids, was isolated from culture filtrate of Clostridium acetobutylicum by salting-out, and its purification was attained to about twenty-fold by treating with calcium phosphate gel. It was shown that racemiase requires for its full activity cofactors, pyridoxamine phosphate and ferrous ions. These substances were detected in the racemiasc preparation. Several other properties of racemiase were also investigated.

Excretion of 5′-Nucleotides from Bacterial Cells

Incubating the dried cells of Brevibacterium sojae No. 425-40 in alkaline buffer, the excretion of 5′-nucleotides accompanying with the decrease of intracellular RNA was observed. Then the determination of the optimum condition of the excretion and the investigation on the enzyme responsible for the degradation of endogenous RNA were carried out.In the experiments using sonicate and disrupted cells, it appeared that orthophos-phate and Mg++ might be accelerative or essential for the degradation of endogenous RNA and, in addition to four 5′-nucleotides (AMP, GMP, UMP and CMP), each nucleoside 5′-diphosphate was also contained in its degraded products. Nucleoside 2′- or 3′-monophos-phates were not detected. Although it was not clear whether phosphodiesterase concerned with the degradation of intracellular RNA or not, it was suggested that polynucleotide phos-phorylase acted mainly on the degradation.The maximal excretion of 5′-nucleotides from dried cells was obtained by suspending 1 to 2% of dried cells in...

Excretion of Ultraviolet-Absorbing Materials by Zygosaccharomyces soja Mutant: Part I. Accumulation of 5′-Nucleotides in the Culture Fluid of Zygosaccharomyces soja Mutant during GrowthPart II. Excretion of 5′-Nucleotides by Autodegradation of RNA from Intact Cells of Zygosaccharomyces soja MutantPart III. Accumulation of 5′-Nucleotides by Autodegradation of RNA in Cell-free Preparation of Zygosaccharomyces soja Mutant

Zygosaccharomyces soja mutant obtained from cycloheximide treatment accumulated several kinds of nucleotides together with riboflavin in the minimal glucose salt medium. Accumulation of nucleotides took place in parallel with the propagation of the microorganism after inoculation. That the nucleotides accumulated were identical to 5′-CMP, 5′-AMP, 5′-UMP, 5′-GMP and UDP, ADP, GDP respectively was verified using chemical and enzymic procedures. It was assumed that the excretion of these nucleotides was mainly carried out by the action of polynucleotide phosphorylase.It was also surmised that the excretion of AMP at the early stage of incubation meant leakage from de novo synthesis.

On the Character of Riboflavin Producing Mutant of Zygosaccharomyces soja

Riboflavin producing mutant of Zygosaccharomyces soja* was obtained by a treatment with cycloheximide. This mutant actively utilized various sugars and excreted riboflavin to the culture medium in a concentration of 30 to 40 μg per ml. Aerobic condition was prefered to sustain the growth of mutant and glucose catabolism was altered from alcohol fermentation in case of mother strain to respiration in mutant. This paper presents data obtained from morphological and physiological investigations.

Characteristics of TCA Cycle of Cycloheximide-resistant Mutant of Zygosaccharomyces soja

Glucose catabolism in Zygosaccharomyces soja was carried out. through fermentation, whereas riboflavin producing mutant obtained by cycloheximicie treatment was found to utilize oxidative mechanisms. For instance, growth of mutant was sustained in minimal medium containing TCA cycle intermediates as the sole carbon source, whereas the mother strain could not grow on such culture media. Furthermore, malonate inhibited the oxidation of succinate with resting cells of mutant. As these results support the existence of TCA cycle in mutant, various enzyme activities relating to TCA cycle were investigated by the use of cell-free extracts of both strains. Aconitase, α-ketoglutaric decarboxylase, succinic dehydrogenase, fumarase, isocitritase and glyoxylic reductase were not detected in mother strain. These data indicated that both the TCA cycle and glyoxylate cycle did not operate in mother strain. On the other hand, all enzyme activities relating to TCA cycle and glyoxylate cycle were verified in mutant. This f...

On the Metabolism of Organic Acids by Clostridium acetobutylicum: Part I. Formation of Lactic Acid and RacemiasePart II. Lactic Acid Metabolism and Relating Role of Racemiase

Authors confirmatively observed the phenomena that in adequate conditions, the mode of acetone-butanol fermentation could be converted into homo-lactic acid fermentation, and that the formation of “Racemiase” (lactic acid racemiase) was intensified through the appropriate lactate level in growing culture of the bacterium, Clostridium acetobutylicum.Furthermore in this series of the papers, the possible role of “Racemiase” in the lactic acid metabolizing sequence was suggested, and the chemical properties of “Racemiase” as well as the mechanism of enzymatic racemization of lactic acid were investigated. The metabolism of several organic acids were also discussed in connection with the fermentation pathway of this organism.