The genetic difference between streptomycin "indifference" and streptomycin "resistance" in our sense has been shown by the transformation experiment using Diplococcus pneumoniae. The recipient strain used is a highly transformable rough strain derived from type II, and the donor strains are a streptomycin "indifferent" strain and three streptomycin "resistant" strains having different histories in their course of acquiring the resistance.
When the recipient strain grew in the transforming system with the extract containing DNA from the "indifferent" donor, a prompt transformation to streptomycin "indifference" occurred in a single step. However, when the same recipient strain was treated with the extracts from the "resistant" donors, the level of streptomycin resistance of the donors was not transferred in a single step. The transfer at this time was usually noticed up to lower levels of the resistance and the trait of high resistance could be transferred, in some experiments, only after repeated treatments with the same extract. The results of this successive transformation were variable according to the history of acquiring the resistance of the donor strain from which DNA was extracted.
The data presented in this paper seem to indicate that while streptomycin "indifference" is controlled by a single gene, streptomycin "resistance" is ruled by two or more genes.

View full abstract

The authors extracted the polysaccharide fraction from the celles of a strain of Candida albicans. This antigen was used in the diagnosis of candidiasis, especially the deep-seated infections, by skin test and precipitin reaction.
The polysaccharide antigen proved to be considerably high in specificity and sensitivity from the results of animal experiments and clinical investigations on human cases. Therefore, the authors consider it a reliable antigen for the serologic diagnosis of candidiasis.

View full abstract

Electron microscopic observations of a BCG strain on ultra-thin sections showed that the cell was composed of a cell wall, cytoplasm containing large electron-optically dense granules and a chromatin thread-like structure in a clear area. The chromatin thread-like structure had fine granules 15-20mμ in diameter attached to it, and extended through the central part of the cell along its longitudinal axis. It gave off fine fibers into the cytoplasm and was supposed to be connected with A-granules at the end portions of the cell. A-granules were isolated by ultracentrifugation from the cells of BCG and Mycobacterium phlei after the cells were disintegrated by repetition of freezing and thawing. Measurement of ultraviolet absorption of the fractions obtained by ultracentrifugation disclosed that the nuclear substances were dissolved and transferred into fraction III after the cells were disintegrated and that fraction II containing A-granules absorbed little or no ultraviolet light. Separated A-granules were identified with those in the cells on the basis that electron bombardment vacuolized all these granules.

View full abstract

Experiments were performed to analyse the biological characteristics of M. ulcerans and other mycobacteria.
M. ulcerans growing at both 33°C and 37°C showed a well developed cording of the type described for virulent mycobacteria.
The acid-fastness and boil-fastness of M. ulcerans are strong, and it gives positive reactions to the neutral red cytochemical reaction and catalase test. The results obtained from the oxidation-reduction potentials of bacterial suspensions and the oxidation-reduction dye decolorization test were essentially similar to those described for virulent mycobacteria. M. ulcerans differed from M. tuberculosis (H37Rv) in its in vitro sensitivity to drugs; high sensitivity to SM and insensitiveness to INH.
In view of the above results, we find it difficult to conclude that M. ulcerans shows essentially similar biological reactions as those obtained with virulent mycobacteria.
While there is a considerable agreement in characteristics, with virulent mycobacteria, the results concerning catalase activity and INH sensitivity resemble those of avirulent mycobacteria. Continued investigations to resolve the problem of biological characteristics and pathogenicity of M. ulcerans are necessary. This must be the subject of future research.

View full abstract

1. The staphylococcal toxin is detoxicated when incubated at 37°C, being added with KCNS in a concentration of 1M.
2. The KCNS-alum-precipitated toxoid shows a good antigenicity in guineapigs.

View full abstract

1. The presence of relatively thermostable toxin in supersonic extract of L. icterohaemorrhagiae suspension was demonstrated by intracutaneous injection into guinea pigs and rabbits.
2. Studies were made on thermolabile hemolysin found in culture supernatants of leptospira and it was suggested that this hemolytic and the above toxins are different.

View full abstract

Four hundred and eighteen culture filtrates of the freshly isolated streptomyces were examined on the activity against influenza virus cultivated in vitro, in which a piece of chorioallantoic membrane of embryonated egg was suspended in Hanks′ solution. The results indicated that 21.5% of the tested filtrates were active. Further, the active filtrates were studied in regard to some of the biological and physicochemical properties such as effect on dehydrogenase activity of the tissue, toxicity for mice, other antimicrobial activities, taxonomic characteristics and solubility of the active agent in the organic solvent. A definite relationship between the antiviral activity and other biological properties could not be established in the present experiment. Eleven active filtrates were selected for isolation of active principles in the respect that they possessed all unique biological properties.
The usage of the in vitro screening of antiviral agents was discussed.

View full abstract

1) By the usual mouse protection test, group-A which received the 3-dosevaccine together with PVL showed a MLD protective value of 8-times greater than the group-B which received the 6-dose-vaccine.
2) On the contrary, group-C which received the 3-dose-vaccine together with the 3-dose-cortisone showed 1/100th the MLD protective value of group-A. And, group-D which received the 3-dose-vaccine and later the 3-dose cortisone showed a protection of 1/52 of the group-A.
3) Also in the immunization experiment on rabbits, a rapid formation of neutralizing antibodies was shown by the combined vaccination with PVL. For example, the vaccine-PVL-group showed N. I. values of 4 times larger at 10 days and 2 times larger at 21 days, compared to those of the simple vaccine-group.
4) In the similar immunization experiment, a group which received cortisone of 4mg/kg of body weight in successive days showed low N. I. values like 1/10 of the vaccine-PVL-group and 1/3 of the vaccine-group at 10 days, and 1/6 of the vaccine-PVL-group and 1/2 of the vaccine-group at 21 days.
5) Cortisone gave rise to the increase of susceptibility of mice to rabies virus and emaciation of rabbits.

View full abstract

1) The growth inhibition on the desoxycholate-citrate medium is restored by the addition of magnesium and manganese ions among Mg⁺⁺, Ca⁺⁺, Al⁺⁺⁺, Mn⁺⁺, Fe⁺⁺, Fe⁺⁺⁺, Co⁺⁺, Ni⁺⁺, Cu⁺⁺, Zn⁺⁺ and Cd⁺⁺. Manganese ion stimulates especially the growth of colon bacilli.
2) For simplification of working conditions, a synthetic medium was devised.
3) Citrate without co-existence of desoxycholate has no growth inhibiting effect under the conditions tested. Lactose has only the role of an indicator of lactose-fermenters.
4) Free magnesium ion concentration in the medium and the growth of organisms on it are proportional when desoxycholate co-exists. And it is considered that the main role of citrate in this medium is to decrease the free magnesium ion concentration and to promote the effect of desoxycholate. The difference of requirement of free magnesium ion between the colon and dysentery bacilli appears to be one of the main principles for the selecting effect of this medium.

View full abstract