1. Metabolizing activities of Nocardia sp. CF 222 on phenol and 21 related substances were examined. Eight of these substances including phenol could be metabolized. Some of the utilizable substances exhibited toxicity at higher concentrations, while homocatechol, benzoate and phenylphosphate had no such effect at the highest concentration tested (25×103μg/10ml). 2. Cultures of the organism in synthetic media containing glucose or phenol and in a nutrient broth have revealed that in all cases the cells release phosphorus compounds into the culture medium at a later stage of logarithmic growth. 3. Cells grown in different media (synthetic medium containing glucose or phenol and a nutrient broth) were followed for their morphological changes during the culture. It was found that in the nutrient broth and in the synthetic glucose medium the cells assumed, at first, a form of long branched mycelium which later divided to give rise to short rods and coccoid forms, whereas in the synthetic phenol medium the cells remained to be long rod without dividing into shorter cells. 4. Although the organism can grow in a synthetic glucose medium containing ammonium sulfate as the sole nitrogen source, its growth is considerably accelelated when ammonium was substituted with tyrosine. Such an effect was not observed with vitamins B1 and B2, biotin, adenine, guanine and uracil.
Phosphorus metabolism of Nocardia sp. CF 222 was investigated using 32P as a tracer. It was found that the rate of phosphate incorporation into the cells was higher at the logarithmic phase than at the stationary phase. A large amount of phosphorus compounds was released at later stage of logarithmic growth, and 65% (in terms of phosphorus) of them were released in a form of inorganic phosphate. In parallel with the release of phosphorous compounds into the medium, there occurred a decrease of acid soluble organic phosphorus compounds in the cells. Columnchromatographic analysis showed that the cells at different phases of growth in a nutrient broth had essentially the same patterns of nucleotides and related compounds. However, some changes in the pattern were observed when the cells were grown in different media or when the cells grown in nutrient broth for 35hr were transferred to a fresh synthetic medium deficient in phosphate.
1. Various kinds of auxotrophic mutants were derived by X-ray irradiation from an adenine requiring mutant of Bacillus subtilis which accumulates hypoxanthine in the culture medium. 2. Among these mutants, some were found to have acquired the ability of accumulating inosine. Some mutants accumulated only inosine but not hypoxanthine, others both inosine and hypoxanthine in varying ratio. One of the adenine-histidine requiring mutants had the highest level of inosine productivity, and its productivity could be improved by further mutation. 3. A mutant which produced inosine alone was found to have almost lost the ability of degrading inosine to hypoxanthine. The genetic conversion of the pattern of such accumulation was discussed in connection with the inosine degradation ability. 4. The fermentation product was isolated by the use of ion exchange resin "Dowex-1, formate form", and by acetylation it was converted to 2′, 3′, 5′-tri-0-acetyl-inosine. Thus the fermentation product was identified as inosine by comparison with its authentic preparation.
Using three typical inosine-producing mutants of Bacillus subtilis, the effect of medium composition on the inosine productivity was investigated. 1. To allow the bacteria grow and accumulate inosine, the synthetic medium should contain, besides suitable carbon and nitrogen sources, certain amounts of adenine and some amino acids. A considerable increase of inosine production was brought about by the addition of yeast extract or dry yeast to the medium. Excess amount of adenine was found to repress the inosine formation. 2. As the bulk carbon source, various kinds of carbon compounds belonging to hexose, pentose and polyalcohol were utilized. Glucose and starch hydrolysate were the most suitable. 3. Ammonium salts, urea and nitrates were all usable as bulk nitrogen sources. For the maximum production of inosine, greater amounts of nitrogen were necessary than that required for the full growth of the bacteria.
Using two typical inosine-producing mutants of Bacillus subtilis, the effect on inosine fermentation of cultural conditions as well as the time course of inosine formation was investigated. 1. Sufficient supply of oxygen was requisite for the production of a large amount of inosine. 2. The optimum pH for inosine production was in the range of 5-7. 3. The inosine formation began at 10th hr of cultivation, and was at the highest rate at 30th-50th hr. At 70th-90th hr, the accumulation attained to the highest level, i. e., 7g/liter of the culture medium, which contained initially 6% glucose. 4. The inosine formation proceeded in parallel with the consumption of glucose. 5. Methods for preparing a single compound related to nucleic acids on a large scale was discussed.
It was observed that Streptomyces sp. No. 3558 produced D-4-amino-3-isoxazolidone and 0-carbamyl-D-serine simultaneously. The production of 0-carbamyl-D-serine occurred earlier than that of D-4-amino-3-isoxazolidone in the fermentation process. 0-Carbamyl-D-serine was not converted into D-4-amino-3-isoxazolidone by the cells of the Streptomyces. The use of 14C-labelled 0-carbamyl-D-serine also showed that it was not significantly incorporated into the isoxazolidone molecule by the growing cells. Either DL-serine-3-14C or glycine-14C (U) was significantly incorporated into 0-carbamyl-D-serine and D-4-amino-3-isoxazolidone in the biosynthetic process. D-Glucose-14C (U) was also biosynthetically converted into 0-carbamyl-D-serine. A plausible pathway in the biosynthesis of these two antibiotics is presented.
The site of accumulation of vitamin B12 by the cells of Lactobacillusdelbrueckii No. 1, a B12-requiring organism, was investigated. The principal site of accumulation was found in the cell-wall fraction. The existence of a certain principle binding with the vitamin in the cell wall was suggested. It was also discussed on a possible role of the cell wall in the mechanism of uptake of B12 in this organism.
Glucose-6-phosphate dehydrogenase was partially purified starting from the cell-free extract of Lactobacillus plantarum 11 and the properties of the dehydrogenase were investigated. The intracellular activity of the enzyme was calculated. Using kinetic data concerning the dehydrogenase activity in the presence of various concentrations of coenzyme, and inorganic ions, the activity of this enzyme under the conditions thought to be comparable with an intracytoplasmic environment was calculated to be 0.04μ moles per mg dry weight of cells per hr. This value was 1% of lactic acid forming activity of the intact cells. A similar quantitative relationship was also demonstrated between C14O2 and lactate which were produced from 1-C14-glucose by washed cells. The role of the dehydrogenase in the cells of this organism was discussed with respect to its relation to the homo-lactic acid fermentation.
Using sodium lauryl sulfate, the effect of a surface active agent on oxygen transfer rate in bubble aeration was studied experimentally. It was found that the value of liquid film coefficient in bubble aeration was reduced by the addition of small amounts of sodium lauryl sulfate, less than 100 ppm, to about one-fourth of that obtained in the case without the surfactant. This degree of increase of resistance to oxygen transfer was not ascribed directly to an increase of diffusional resistance due to the adsorption of the substance at the air-liquid interface, but principally to a sort of calming action of sodium lauryl sulfate on the oscillation as well as the other complicated motions of bubble surfaces in aeration.