The ε-caprolactum-utilizing bacteria were searched. Among 40 authentic strains stored in the IAM Culture Collection, only one strain, Pseudomonas ovalis JAM 1002, was found to utilize ε-caprolactam as a sole sourse of carbon and nitrogen. From the polluted water lines of the Nylon 6 manufacturing plant (Nagoya Plant, Toyo Rayon Co., Ltd., Nagoya) 11 strains of this nature were also isolated and identified. Various characteristics of these bacteria are described.
Six strains of spore-bearing lactic acid bacteria were isolated from rhizosphere of various wild plants by means of the following process: A small piece of specimen was immersed in a glucose broth, heated at 80° for 20min, incubated anaerobically, Clostridia allowed to develop, one loopful of the broth was plated if its pH was lowered below 4.0, and the pin-point colonies with transparent haloes were picked up. The isolates are mesophilic, facultatively aerobic, and catalase-positive rods with peritrichous flagella and an oval endospore at the terminal. The characteristic features are as follows: pH value of the glucose, fructose, sucrose and generally inulin broth is brought to 3.8-3.2 with lactic acid produced in the homo-fermentative way. These isolates were classified into the following two new species based on the isomeric types of lactic acid produced: Bacillus laevolacticus nov. sp. for five strains of the l-rotatory lactic acid producers, and Bacillus racemilacticus nov. sp. for the two strains of the dl-lactic acid producers.
Seven strains of catalase-negative, spore-bearing, lactic acid-producing bacteria were isolated from rhizosphere of various wild plants. They are mesophilic, facultatively anaerobic, gram-positive rods with peritrichous flagella and oval endospores at terminal to sub-terminal, and produce dl-lactic acid from glucose, fructose, sucrose, trehalose, and inulin in the homo-fermentative way, lowering the pH value of the medium to 3.8-3.2. Among the hitherto known organisms, only Sporolactobacillus inulinus KITAHARA et al. may be the closely related species to the new isolates.
A sexual interaction was discovered between two strains of Rhodotorulaglutinis considered as haploid. The nutritionally prototrophic mycelial colony was obtained by the conjugation and plasmogamy of cells of their auxotrophic mutants. The mycelial development was also found in the couple of their wild type cells. The mycelium has septa with clamp-connections, and consists of dikaryotic cells. It produces terminally brown pear-shaped resting spores which are regarded as diploid. The resting spore germinates to form a promycelium, on which haploid sporidia bud off laterally. Single sporidium propagates by budding and develops to the same haploid yeast as that of the original Rhodotorula strains. Among monosporidial yeasts, there are two mating types. The same mycelial stage appears again by conjugation of the two mating types. For the perfect stage of these strains of Rhodotorula, a life history is proposed schematically. It was concluded that this organism was related to the order Ustilaginales of Basidiomycetes. After the examination for sexual interaction in many couples of the authentic strains of Rhodotorula, the same mating reactions were found between IFO. 0559, IFO. 0413, or IFO. 0871 and IFO. 0880 or IFO. 1236. The mating types of the former three and the latter two were designated by symbols A and a, respectively. A monotypic new genus, Rhodosporidium, was proposed and a new species, Rhodosporidium toruloides, was given to the perfect stage of these Rhodotorula strains.
An attempt was made to improve the spore-forming ability of Sporolactobacillus inulinus whose sporulation rate was usually only 10-4-10-6 in a population. An improved medium in which sporulation takes place reproducibly at the rate of 1% has been prepared by examining the effect of various substances on sporulation. From cells grown in the sporulation medium, clean spores were separated and the following features characteristic to spores of Bacillaceae were demonstrated: (1) spores could tolerate against the heat treatment at 80° for 10min, (2) electron micrographic profile of the section of the spores was characteristic to that of bacterial spores, and (3) they contained dipicolinic acid at the concentration of 5.16% dry weight.
The addition of 3% of glycine and 10units/ml of penicillin G to a culture of Pseudomonas resulted in a rapid death of the bacterium. More than 95% of viable cells were killed within 30min of incubation. Cell wall synthesis, as determined by amino acid incorporation, was inhibited by glycine plus penicillin. It was also noted that penicillin in high concentrations induced some kind of unbalanced growth. Ethylenediaminetetraacetate in a concentration of 1×10-4M had little or no effect on intact cells or cells treated with penicillin but lysed the cells which were treated with glycine and penicillin. The combined action of these chemicals was successfully utilized for the rapid screening of temperature-sensitive mutants from ultraviolet-irradiated cells. N-Nitroso-N-methylurethane was found to be an extremely efficient mutagen for the isolation of temperature-sensitive mutants. The frequency of mutation was so high that mutants can be isolated without any screening procedure.
Nine good hydrocarbon utilizers including Corynebacterium hydrocarboclastus, Alcaligenes marshallii and yeasts were isolated. They showed abundant growth on a simple synthetic hydrocarbon medium after 24-hr incubation. Various auxotrophic mutants derived from them produced the following amino acids: Ornithine, valine, glutamic acid, leucine, tyrosine, alanine, proline, aspartic acid, and lysine. The anticipation of this method for fermentative production of amino acids from hydrocarbons was also discussed.
Employing Aspergillus niger strain 1617, we have made a kinetic analysis of the region of protease formation in the hypha. When the fungal hyphae, grown by shaking in the ordinary synthetic medium containing sulfate (+S medium), were transferred to the same medium devoid of sulfate (-S medium), they produced acid protease after an induction period of 5hr. Making use of this phenomenon, the fungal conidia were grown in several batches of +S media (primary culture) each for different period and the growing hyphae transferred to -S media (secondary culture). Then the course of protease formation was followed in each culture. From the kinetic analysis of the data of the above experiments, it was concluded that the apical growing region of ca. 40μ does not respond to the S-deficiency which causes protease induction, and the portion, following this, of ca. 30μ responds to the S-deficiency. The inducible region is followed by a region of protease formation. The site of septum formation in relation to these regions is discussed.