Morphological studies were made on the strain of Corynebacterium, described previously. The main morphological changes were marked enlargement of the cells and formation of the spherical forms, irrespective to the nature of the antibiotics, though in some cases, especially in chloramphenicol cases, rod-like structures or net-works were sometimes found. These spherical or enlarged forms should have the same significance to the spindle forms in Escherichia coli, reported previously by the author.
The authors studied usefulness of the deoxyribonuclease test as an aid in the identification of pathogenic staphylococci with reference to the constitution of medium and criteria for determination. The constitution of the test agar divised by the authors was heart infusion agar added with 0.2% of DNA and 0.045% of CaCl2. Addition of NaCl in more than 0.5% to the medium proved to inhibit the DNase production of staphylococci. The most appropriate time to determine the reaction was shown about 15 minutes after pouring 1.5N of HCl onto the plate cultivated at 37°C for 18 hours. Using the above test medium, 395 strains of staphylococci freshly isolated from various sources of clinical specimens were investigated the DNase activity in comparison with coagulase production and several other biological properties: 193 strains of coagulase-positive staphylococci were all DNase-positive and 202 strains of coagulase-negative ones DNase-negative with exception of 8 strains. Furthermore, the correlation between DNase activity and coagulase production was found to be the closest among all the biological attributes of the strains tested. Thus it may be concluded that the DNase test agar divised by the authors is also useful for identification of pathogenic staphylococci isolated in this country.
We discovered that some S. typhi (V type) produced strong soluble protective antigen (SPA) that did not contain any toxity in TSA media. It is not O-antigen because it is not produced from W-type and Schwartzman reaction is negative; moreover it is not assumed to be Vi-antigen or heat-labil-protective antigen as Jenkins, because it is not produced from B. Ballerup containing Vi-antigen in common with S. typhi. We assume it to be a kind of soluble antigen of a new type, different from the well-known somaticprotective-antigen.
Cells of the Reiter treponeme were disrupted by sonication and fractionated by differential centrifugation. The cell fractions were tested for the electron transport system. The particulate fractions gave a reduced with Na2S2O4 minus oxidized difference spectrum consisting of peaks at 630, 562, 530 and 429mμ. The peaks at 630 and 562mμ seem to correspond to α-bands of a2-and b-types of cytochromes respectively and the peak at 530mμ may be characteristic of a β-band of the cytochrome b. The high peak at 429mμ may correspond to a Soret band of the cytochrome b. A marked trough with its maximum at 460mμ may be attributed to flavoprotein. Since only the Soret region at 429mμ can scarcely be seen in the supernatant following centrifugation at 104, 000×g, the cytochromes of the treponeme appear to be associated with the cytoplasmic membrane and the membranous structure as in bacterial cells. Higher activity of succinic dehydrogenase was localized in the particulate fractions than the supernatant obtained by centrifugation at 104, 000×g. NADH2 oxidase activity was found both particulate and supernatant fractions, but was generally higher in the supernatant fraction.
The investigations concerning biological properties of Mycoplasmas were carried out from the points of view of heat, pH and shaking stabilities. The Mycoplasma strains used were M. pneumoniae CL. FH, M. orale N-1, and M. salivarium-C Hup 127. M. orale N-1 was kindly supplied by Dr. Hayflick, who isolated this strain from human leukemia patients by direct agar method. These mycoplasma suspensions were tested in the resting states. The results obtained were as follows: 1) Resitance of three strains to heat was generally labile, especially that of M. orale was markedly thermolabile; it was inactivated at 50°C for 30min. The other two strains was throughly inactivated at 55°C for 30min. 2) Stability of strains to pH is characteristic; Mycoplasmas, in general, were very weak to acid, but fairly stable to alkali. M. pneumoniae and M. orale survived for 48 hours in pH 7.76. M. orale survived for 24 hours even in pH 8.9. 3) It was interesting in the case of stability of strains to shaking that Mycoplasmas were not destroyed by shaking of 150 rev. per min., but M. salivarium and especially M. orale increased their viable units, that is, the number of colonies increased by shaking, comparing with that under the stational condition.
1) The suspenion of E. coli was heated under the environment of oxygen with from 1 to 10 absolute atmospheric pressure (aap). At each temperature, the decimal reduction time showed a peak at 1aap, and then decreased as the pressure rose. 2) When E. coli was cultivated under the hyperbaric oxygen, the lag time was delayed with the increase of pressure up to 4aap. At 5aap or more of oxygen, no bacterial growth was observed. Generation time increased linearly with the pressure of oxygen up to 3aap. 3) The pretreatment with hyperbaric oxygen had not effect on the growth rate thereafter. 4) When the culture was oxygenated during the growth phase, the following relationship was observed between the number of the microbes (N) and oxygen pressure (p) N=N0e(3.7-0.8p)t(t: time in hour) 5) The amount of final growth showed the peak at 1aap. Exceeding 1aap, the amount diminished remarkably with the rise of the pressure. 6) Hyperbaric nitrogen showed no effect on the growth of bacteria. 7) Reducing agents added to the media had no protecting effect against the oxygen action on E. coli. 8) Antimetabolites showed the synergic, antagonistic and indifferent attitude toward the effect of hyperbaric oxygen depending on the mode of action of the chemicals.