The lethal and mutagenic effects of continuous irradiation with radioisotopes, P³², S³⁵ and Sr⁹⁰, on the growing and metabolizing population of a Mycobacterium were studied.
Continuous irradiation with P³²-isotopes added as p³²-orthophosphate at a concentration of 0.5μc/ml to a medium exhibited lethal and mutagenic effects during a four week observation period, but the effects became insignificant after five or six weeks of incubation. The effects were more prominent in the Sauton medium, in which the organism grew abundantly, than in the phosphorusdeficient medium, in which it grew only poor and slowly. However, greater amounts of P³² were incorporated into the cells growing in the phosphorusdeficient medium than these cells growing in the Sauton medium. The effects on the growing and metabolizing bacterial population were not too affected by the content of P³²-atoms in the DNA or in the total cell as it affected the frozen and resting cells. On the other hand, the population was considerably affected by the physiological condition of the cell. The lethal effect was less in the metabolizing population than in the frozen population.
The addition of 5μc of S³⁵-sulfate per ml to sulfur-deficient medium, in which the organism grew abundantly, could cause neither mutagenic nor lethal effect on the metabolizing population at least during a six-week observation period, whereas the addition of 0.5μc of P³²-phosphate per ml to a medium exhibited a significant change.
A continuous irradiation of the organism, which grew slowly in a phosphorus-deficient medium containing 2μc of Sr⁹⁰-nitrate per ml for a 285-day irradiation period, caused a significant increase (a 27-fold increase) in mutation frequency to isoniazid resistance but caused a slight increase (a 3-fold increase) in viability.
It is suggested that, in the growing and metabolizing population also, lethal and mutagenic effects are produced chiefly by transmutation and that a longterm irradiation with beta-ray (Sr⁹⁰) also caused an increase of mutation frequency without the accompaniment of a significant loss in viability.

View full abstract

The fine structure of C. albicans was studied by electron microscopy of ultrathin sections. In yeast-like cells, the cell wall is made up of two layers, and the cytoplasmic membrane is resolved into two dense layers separated by a light layer, which correspond to the components of the unit membrane. The nucleoplasm is enclosed in the nuclear membrane, which is also made up of the unit membrane and in which nuclear pores are apparent. The intracytoplasmic membrane system in manifold appearance is observable. Especially the structures resembling the mitochondria and endoplasmic reticulum in higher organisms are noted. This intracytoplasmic membrane system is seen to be connected to the nuclear and cytoplasmic membranes as well as to the mitochondria-like structures. Formazan granules appear to deposit in correspondence with the site of the intracytoplasmic membrane system. The chlamydospores are surrounded by the thick cell wall, and rich in lipids. The internal membrane is also observed in the chlamydospores, though indistinctly. The fine structure of the pseudomycelial forms is not greatly different from the yeast-like forms.

View full abstract

Sera obtained from 145 patients were tested for the presence of circulating antibodies by means of the agar-diffusion technique. The antigens employed were cultures of human tubercle bacillus H37Rv, bovine tubercle bacilli BCG, Ravenel, RO, and 263, as well as the atypical mycobacterial strains^(1-3.5) Fortyseven of the 145 serum specimens gave positive reaction. Thirty-eight of the 47 serum specimens reacted with the antigen of H37Rv, and 29 of 38 serum specimens produced the reaction only with this antigen (positive rate 76.3 per cent). The remaining sera demonstrated a common reaction with the antigens of bovine tubercle bacilli and atypical mycobacterial strains. Seven of the 145 patients were found to contain atypical mycobacterial antibodies, and two sera from the seven patients reacted only with the antigens of atypical mycobacterial strains; the others showed a common reaction to the antigen of the other mycobacterial strains. None of the sera reacted with any of the antigens of saprophytic mycobacterial strains. Only one of the serum specimens obtained from the 54 healthy nurses was found to contain an antibody to antigen of the atypical mycobacteria. In this nurse no previous history of tuberculosis was evident.

View full abstract

A phenomenon of suppressing plaque formations (abbreviated as spp.) of phages λ and Plkc by some R factors, which were used to infect the host cells of these phages, was described. In this respect, the R factors were divided into two groups; one has the character (spp (+)) and other has not (spp (-)). All of the spp (+) R factors tested were confirmed to be ri^-, that is, not to be endowed with the character of recombination interference. All of the ri⁺ R factors were spp (-). One case of ri- and spp (-) R factor was found. No difference could be observed between the adsorption rate of phage λto the resistantized cells carrying spp (+) R factor and those to the sensitive cells or to the resistantized cells carrying the spp (-) R factor. The phage λ (281), which was prepared by growing the original phage λ on the resistantized strain carrying the spp (+) R factor, was not suppressed by the spp (+) R factor. The insusceptibility of phage λ (281) was, however, not hereditary, and it became susceptible to the suppressive effect of the spp (+) R factor when it was again propagated on the sensitive strain. The change belongs, therefore, to the"host induced modification" or "host controlled variation" Thus, the spp (+) R factor, by which the host cells of phages are infected, changes the process of phage multiplication to decrease the number of plaques formed on one hand and for the progeny phages to be modified in their host specificity similarly to"host induced modification" or "host controlled variation" on the other. Some possible mechanism of the phenomenon of spp. and the modification, induced by the spp (+) R factor, were discussed.

View full abstract

1) The oxidative activities of the members of dicarboxylic acid cycle by cells of A. aerogenes A-1, adapted to D-glucuronic acid, were superior to normal cells.
2) The cells adapted to D-glucuronolactone and ethyl-D-glucuronate were superior to non-adapted cells in the oxidative activities of the members of dicarboxylic acid cycle.
3) The stimulation of dicarboxylic acid cycle is considered to be one of the mechanisms of promoting action of D-glucose metabolism by adaptation to D-glucuronic acid derivatives.
4) D-glucuronic acid, D-glucuronolactone and ethyl-D-glucuronate are supposed to be degraded by the same or closely related enzyme systems.
5) The permeability of D-glucuronolactone through cell wall was inferior to that of D-glucuronic acid and ethyl-D-glucuronate.

View full abstract

The authors, for the first time, were able to isolate O. spp., possessing pathogenicity to mouse, from the body surface or enteric canal of fishes or from coastal sea-water and so forth. These results led the authors to the oceanic surveys. Among Vibrios there are some species of bacteria which can kill a mouse, however, they can grow abundantly on ordinary culture media containing 0.5% NaCl. As far as this character is concerned they are more likely to be classified into the category of land bacteria, non-halophilic organisms. Since our oceanic surveys revealed that a bacterium exist in the ocean which has the same serotypes as that of the food poisoning causing bacteria, it has become apparent for the first time for marine bacteria to be recorded as a human pathogen.
The existence of two types of O. spp., euryhaline and stenohaline, is of significance for the epidemiology of food poisoning and marine industry. Oceanomonas spp. of the euryhaline type which could be isolated from samples obtained from only two stations near the coast of the Sagami Bay during the winter (Fig. 3b) play a predominant role in the summer sea by driving away the stenohaline type (Fig. 1b): euryhaline- and stenohaline types of O. spp. are representatives of the microflora which take their place in summer and winter. The winter sea which abounds with avirulent stenohaline type, seems clean and healthy, whereas the summer sea, abundant in virulent euryhaline type, representing a reserve army, is conducive for food poisoning to occur. These contrasted two phases were called by the author as "winter" and "summer-type distributions" These could easily explain the epidemiological facts that fish and shellfish food poisoning are prevalent mainly during the summer season, particularly from June to October. Besides such seasonal alterations, a phenomenon of "habitat segregation" also became apparent, i. e., as depicted in Fig. 2, the euryhaline types are located, in general, near the shore whereas the stenohaline types in the offshore. This evidence could also explain the fact that this food poisoning are mainly caused by those coastal marine animals as mackerel, squid, octopus, shellfish, and so forth.
In view of the prevention of food poisoning caused by pathogenic halophilic bacteria, the use of. ice, especially for the period of preservation, preliminary washing with enough water for elimination or sterilization of the organisms, and the use of vinegar at the time of cooking, are to be recommended, because the euryhaline type of O. spp. is weak and sensitive to fresh water, low temperatures, and to acid.
Most promising and active way of preventing fish and shellfish food poisoning in the future could be provided, according to the author's proposal, by an oceanographical forecasts as to the distribution and MPN of euryhaline type O. spp.

View full abstract

A continuous oral administration of antibiotics, mostly chloramphenicol, in combination with resistance-lowering agents, such as carbon tetrachloride, cortisone acetate and croton oil, was very effective in establishing infections in ddN and CFW strains of mice when they were challenged with resistant strains of Shigella flexneri 2b and 3a.
The inoculated organisms remained in the intestinal tract for about a week in most of the animals and for as long as 4 or 5 weeks in a few.
Pathologic examination revealed that lesions developed in various organs, especially the intestinal tract, showing acute or chronic colitis.
Infection was not induced in animals which were inoculated with sensitive strains; because of the disruption in the administration of antibiotics to these animals, no organisms could be found in their feces within 1 or 2 days.
Thus, it is concluded that the elimination of intestinal microbial flora with the aid of antibiotics is of primary significance in establishing Shigella infection in mice, and that the resistance-lowering agents seem to play a secondary role in accelerating the infection.
Differences in the serotypes of Shigella flexneri (2b and 3a) and in the sexes (male and female) and strains (ddN and CFW) of the test animals did not seem to influence the grade or course of infections as far as the results obtained were concerned.

View full abstract