Cells of Listeria monocytogenes, were fixed with OSO4 in acetate-veronal buffer containing CaCl2 and NaCl, and treated with uranyl acetate, and after embedding in methacrylates, the thin sections were examined with an electron microscope. A lower density nuclear region occupying the central area of the cytoplasm is filled with fine fibrils. The cytoplasmic membrane consists of a double layered membrane separated by a lighter interspace. The cytoplasmic membrane invaginates into the cytoplasm and seems to be reorganized into the intracytoplasmic membrane system which appears in electron micrographs in a variety of configurations, such as parallel stacks of membranes, lamellar structures and clusters of vesicles, frequently adjacent to the cell wall and to the newly forming septum, and sometimes extends into the nuclear region. These membrane systems appear in cells at all the stages of cultural development, and even in partially autolysed cells as slightly disorganized structures.
Using typing phages 80 and 81, transductions of tetracycline- and erythromycin-resistances in Staphylococcus aureus were investigated and the following results were obtained: 1) Tetracycline-resistance was transduced to about 50-70% of those strains belonging to phage types of group I or III with the aid of typing phages 80 and 81. Many of the strains which belonged to phage types of group II or the non-typable group were not transduced. 2) In the experiment on transduction of erythromycin-resistance, about 10-17% of the 160 test strains of Staph. aureus were competent recipients of this marker. No distinct relationship was found between the phage types and the competence of the test strains to serve as recipients of the EM-marker.
1. Screening tests for bacterial strains which can produce glutamic acid from petroleum or related hydrocarbons were carried out. 2. Various bacteria were found to display capabilities of accumulating glutamic acid in the cultural broth containing kerosine, light oil, heavy oil or liquid paraffin as the carbon source. 3. The highest level of glutamic acid production from kerosine, i.e. 281μg/ml, was obtained with a strain of Corynebacterium hydrocarboclastus.
Using a sensitive fluorometric method, the contents of NAD and NADP in various strains of lactic acid bacteria were measured and they were compared with those in some other microorganisms. The contents of the two coenzymes in lactic acid bacteria were found to be astonishingly high, as exemplified by the NAD content found in some strain which was as high as 0.78% of cell dry weight. Among the lactic acid bacteria tested, homofermentors in general were found to contain more NAD and less NADP compared with heterofermentors. The experiment, in which the levels of the coenzymes in L. plantarum were regulated by varying the quantity of nicotinic acid in the medium, showed that the racemiase activity of the cells was markedly dependent upon the intracellular concentration of NAD, while it was not the case with the glycolytic activity of the same cells. Some discussions were made on the significance of high level of NAD in lactic acid bacteria.
It was shown that an oxidase system which is highly specific to glyoxylate is located in the particulate fraction of Acetobacter dioxyacetonicus. The enzyme system can use both oxygen and 2, 6-dichlorophenolindophenol as electron acceptors, and its activity is independent of TPN or DPN, which distinguishes this system from the glyoxylic dehydrogenase purified from Pseudomonas oxalaticus by QUAYLE and his coworkers (7). It also differs from "coenzyme independent aldehyde dehydrogenase (8)" and xanthine oxidase in the substrate specificity, the optimal pH, etc.
A motile, spore-forming and rod-shaped bacterium was isolated from a chiken feed. The strain is Gram-positive, catalase-negative and is a typical homo-lactic acid fermenter producing leavo-rotatory lactic acid. Taxonomic position of this unusual strain was discussed and it was suggested that the organism represents an intermediate form between Lactobacillus and Clostridium, for which erection of a new subgenus Sporolactobacillus (in Lactobacillaceae) was proposed. The species was named Sporolactobacillusinulinus nov. sp. taking into account its powerful inulin fermenting activity.
Taxonomical studies on the genus Pseudomonas were carried out with 28 species and 202 strains, including those obtained from several type culture collections as well as those isolated from various sources by the authors. The cultural, biochemical, physiological and ecological properties of these organisms were found to be more or less closely correlated to the characteristics of pigmentation. In respect to the pigmentation characteristics, distinction was made of three groups which were named: Fluorescent group, Achromogenic group and Chromogenic group.
Using 28 species and 202 strains belonging to the genus Pseudomonas, comparative studies were made of the capacity of utilizing various organic compounds, of metabolizing carbohydrate under aerobic and anaerobic conditions, of oxidizing gluconate, of producing acetylmethyl carbinol, etc. By and large, the metabolic features were found to be closely correlated to the pigmentation characteristics of the organisms, according to which the present authors have classified the genus Pseudomonas into three groups: namely fluorescent group, achromogenic group and chromogenic group. Nearly all the strains known as oxidative bacteria such as Ps. aeruginosa, Ps. ovalis, and Ps. schuylkilliensis were found to belong to the fluorescent group, while the strains belonging to the other two groups are generally poor in oxidative activities.
Amylase productivity of strain K of Bacillus subtilis was transduced to a negative mutant of the same strain by the mediation of phage SP-10. The amylase locus on the chromosome seems to be linked with the ura-cys locus.
The fine structure of hyphae in Aspergillus niger has been investigated by means of ultrathin sectioning and electron microscopy with special reference to the developmental stages of colonial growth starting from germinated conidia. Cell components such as cell wall, cell membrane, nuclei encircled by nuclear envelope, mitochondria with cristae, endoplasmic reticulum and several kinds of cytoplasmic granules have been observed in common to all hyphae obtained from any region of a colony. Structural differentiation in hyphal cells taken from different loci in a colony has been distinguished in particular by characteristic changes in membraneous systems in cytoplasm; hyphae in the extending zone showed rather typical structures of nuclei and mitochondria and remarkable inf oldings of cell membrane, while cells found in the productive zone are characterized by the presence of irregularly extended mitochondria, the appearance of which is confused with that of endoplasmic reticulum. Continuities among such membraneous structures have been clearly demonstrated. Large vacuoles were shown to contain a number of polyphosphate granules as revealed by the OsO4-fixation followed by Pb-acetate treatment. Granules appearing in association with septum formation were also described. Mycelia of the fruiting and aged zones were characterized by the deposition of electron dense granules in the KMnO4- fixation. These granules may probably be the aggregates of denatured cytoplasmic protein.
Studies were made on the characterization of the genera Nocardia, Mycobacterium and Streptomyces by means of infrared spectrophotometry of whole cells obtained by the shaking culture. Spectra of 12 strains of mycobacteria, 37 strains of nocardia and 16 strains of streptomyces were investigated. It was found that culture ages of the test organisms may affect the spectral configuration to some extent, but considerably uniform spectra were obtained during the stationary phase of their growth. Among the investigated culture media, the glycerol Kelner-Morton medium proved to be most useful as it gave cells showing characteristic absorption bands in the spectra. Four regions in the spectrum were chosen for the differentiation, and each region was further classified into 5 types according to shape and relative intensity of selected key absorption bands. Good correlation of the spectral conformation and biological properties of test strains was noticed. Spectral analysis also suggested that whole cell infrared spectrophotometry would reflected characteristic chemical components of nocardia as an intermediate between mycobacterium and streptomyces.