The biochemical characteristics of 25 strains of the genus Serratia isolated from the stools, sputum, infected areas of humans and from the air were studied, and the following results were obtained: I) Some strains did not produce prodigiosin known as the pigment characteristic to the genus Serratia, although they showed the same biochemical characteristics as the pigment-producing strains. And, it was also noted that a large number of strains were lactose non-fermenters. 2) For this reason, it is believed that in isolating the members of the genus Serratia the main emphasis placed on the ability to split lactose and to produce prodigiosin is not always appropriate. 3) It seems difficult to differentiate the three species of S. marcescens, S. indica and S. plymuthica by biochemical studies only.
Moeller emphasized the significance of decarboxylase of arginine, lysine, ornithine and glutamic acid, for the classification of Enterobacteriaceae and he tested further about the decarboxylase of some other amino acids but the distinctive results could not be obtained. Here author tested the Citrulline decarboxylase by Moellers media, if the classification of Enterbacteriaceae is possible or not, and the following results were obtained that the remarkable difference was detected between Morganella and Rettgerella, but about other genera of Enterobacteriaceae the differences available for classification were not found.
Salmonella typhi H 901 w cells developed in abnormally elongated filament cells in presence of penicillin. The ultraviolet inactivation kinetics of the filament cells were examined in this paper to investigate the relationship with nucleic acids component and chromatinic bodies in these organisms. 1. Throughout the process of the filament formation, DNA and RNA synthesis proceeded without inhibition. 2. The composition of DNA of normally harvested Sal. typhi H 901 w was analysed by a method of phenol extraction in 2M NaCl soltuion. The result was that, Adenine; 22.75, Guanine; 27.15, Cytosine; 27.75, Thymine; 22.35. In contrast with this finding, concerning the result of the base analysis in the filament cells, no reasonable accordance was attained in four trials performed separately. 3. By a method of ultraviolet inactivation, no remarkable increase of target number in the filament cells was observed in no proportion to multiplement of chromatinic bodies in the cells. 4. Seventy per cent of biomass of the filament cells revived after transfered to a fresh medium without penicillin. The finding of this study suggest a probability that some extra-nuclear factor would take a part in the mechanism of cell division.
At the time of investigating the degree of acid-fastness among various types of Mycobacteria, the present authors were attracted by the fact that a smear of M. smegmatis, which was left on the desk near the sunny window, has lost remarkably the acid-fast stainability. This was assumed to be an effect of ultraviolet light. Smears of single cell suspension of about 50 germs per field were dried and irradiated from 10cm distance for various time periods employing a germicidal lamp, Matsuda GL 15, light of which is consisted mainly of the wave lergth of 2537 Å. The irradiance was assumed to be about 1, 200μw/cm2/min. according to Azuma et al's irradiance curve. Irradiated smears were flame fixed, stained with victoriablue solution by heating, and were rinsed in a 0.1% nitric acid-70% ethanol for 20 minutes. Then they were blotted with filter paper and were counterstained with a 10 fold dilution of Ziehl's phenolfuchsin for 10 to 20 seconds. Bacterial numbers in 20 fields at random were counted on 3 slides each per one strain to the respective irradiation time to make total bacterial number approximately to 2, 500∼3, 500. Results in Exp. 1 revealed that the loss of acid-fastness varied to a considerable extent in the different strains or types (Table 1). The loss of acid-fastness demonstrated S-shaped curves as the function of irradiation time (Fig. 1). The average irradiation times required for the complete loss of acid-fastness calculated in Exp. 2 employing 129 stock cultures were shown in Table 2. Difference in the irradiation time between the virulent and the avirulent mammalian types was repeatedly demonstrated and extremely interesting phenomenon. After UV irradiation for sufficient long time periods, the bacterial cells of all types were no more restainable by the ordinary acid-fast staining procedures as shown in Exp. 3 suggesting that the cell wall became more porous by the destruction due to the UV energy. Relation between the acid-fastness and Gram positiveness was investigated in Exp. 4. The results revealed that the gram positiveness was not deprived even from saprophytic Mycobacteria by the prolonged UV irradiation for about 20 hours suggesting that the acid-fastness and the gram positiveness are of quite different mechanism.
Clearance of virulent or avirulent Staphylococcus from the peritoneal cavity of mice was inhibited in the presence of coagulase. More abscess were found in peritoneal cavity of infected mice with coagulase than that of control mice without coagulase. Thus, it was suggested that coagulase intensified not only the invasiveness of the organisms but also promoted the abscess formation at the locus of infection.
1) Staphylococcus aureus 248 βH strain is one of the mutants producing β-hemolysine isolated from 248 orig. As was reported in the previous paper this mutant strain shows at the same time much higher virulenc for mice and rather better growth in ordinary nutrient media than those shown by the original strain. The previous paper reported that 248 βH could occur by one step mutation from 248 orig. However, the subsequent studies revealed that sigregation could be seen at least between the ability of producing β-hemolysine and the virulence for mice. 2) The virulence of 248 βH for mice shown upon the intravenous infection primarily depends on its ability of growing in the mice kidney. 3) It would be likely considered that the following two phases could be separated in the course from the intravenous infection with 248 βH to the death of the infected mice: primarily the successful growth of 248 βH in the kiney of the infected mice and secondarily the attack of some unkown lethal agent produced chiefly in the kidney during the proliferation of the cocci against its target organ. However, neither the nature of that lethal agent nor its target organ have yet investigated in the present step of our studies. 4) The mice infected with sublethal dose of 248 βH retain for a long time, the survivals of cocci in their kidney and show a stable and strong resistance against the superinfection of the same or the homologous virulent strain of staphylococci. 5) The resistance of such high level as those observed in the mice being infected with 248 βH could not be aquired by the pretreatment of mice with the large dose of living organisms of 248 orig or killing vaccine of 248 βH although the latter two treatments could make the mice to survive a little longer than untreated control mice. 6) Some advantages of the characters provided by this experimental system for the analysis of the staphylococcal infection and its immunity were disscussed.
Vibrio parahaemolyticus, a food poisoning microorganism, was demonstrated to have a generation time of 11-13min. (sometimes 9-10min.) when cultivated at 37°C on Monod type shaker in tube containing 15ml of brain heart infusion (pH 7.6) supplemented with 2.5% NaCl. Growth was estimated turbidimetrically at 470mμ, after which culture broth was diluted to one-seventh with 1/200 formalin (in 3% NaCl), using a Hitachi spectrophotometer. Generation time was obtained from optical density value of the growth curve. When the organisms in log phase as the inoculum was used and when a small inoculum was used, a shorter generation time was noted. There was no difference of generation times in strains isolated from patient feces, food stoffs and sea water, and in strains grouping biotype 1 or 2. It was also observed that 10min. of the generation time was determined in viable counts, 13min. in particle counts, 15min. in packed volume method, and 14min. in turbidimetrical method, respectively. In some cases V. parahaemolyticus has been observed to have a generation time of 8-8.9min. in viable counts. This is the shortest generation time reported to date.
Japaneses B encephalitis (JBE) virus investigated was Gl strain which was serially passaged into primary hamster kidney tissue cultures more than 150 generations. The virus infected culture fluid was used in the following experiments and this was designated as “TC strain”. On the other hand, the mouse-passaged original JBE virus (Gl strain) of more than 250 generations was also used for comparison with the former and designated as “M strain”. Some experimental methods and results obtained are summarized as follows: (1) The chromatographic behavior of the M and TC strain viruses on DEAE-cellulose column: Each virus suspension diluted in the medium was load onto DEAE-cellulose column and eluted with 0.07M phosphate buffer (PH 7.2) increasing stepwise from 0.1 to 0.6M NaCl. The eluates were fractionated in every 10ml and their viral contents were assayed by inoculating into hamster kidney cell cultures. From these results obtained, it was found that more than 74% of the TC strain virus was recovered in earlier fractions (1 to 6) of the effluent and its elution pattern showed a simple curve. On the contrary, the M strain virus was slowly eluted from the cellulose column. (2) Interaction between the viruses and some animal tissue homogenates: Each virus suspension was mixed with the tissue homogenates, incubated at 37°C for 2 hours, and then centrifuged at 15, 000rpm for 30 minutes. The infectivity of residual active virus in the supernatant fluid was titrated by inoculating into either mice or hamster kidney cell cultures. The infectivity of M strain virus was completely inactivated by the brain tissue but not liver or kidney tissue homogenates of mice. On the the other hand, the infectivity of the TC strain virus was affected, to similar extents, by the brain, liver or kidney tissue homogenates of mice, and inactivated, more or less, by the liver or kidney tissue homogenates of hamster. (3) Thermal inactivation of the viruses: The thermal inactivation rate of both virus strains was determined at different temperature. The infectivity of the TC strain virus was completely inactivated by being heated at 55°C for 30 minutes, while about 0.01% of the TC strain virus had shown the viral infectivity. After incubation at 40°C for 120 minutes, about 1.7% of the TC strain virus remained active and, on the contrary, the surviving rate of the M strain virus was only 0.1% under the same condition.