The comparative studies of the flagellation and biochemical characteristics were carried out on 3 strains of Kluyvera citrophila, 2 strains of Kluyveranon-citrophila and 24 strains of Escherichia and the other related genera. The flagellation of both species of Kluyvera was found to be peritrichous. Having made clear the mistake in this respect of the original description, the authors proposed to transfer the species of Kluyvera to the genus of Escherichia of Enterobacteriaceae.
DL-Glutamic acid-2-14C and DL-glutamic acid-3, 4-14C were definitely incorporated into the molecule of variotin, when labeled glutamic acid was introduced into the culture of Paecilomyces varioti in the early period of variotin production and the culture was harvested after the production reached the maximal level. The radioactivity was observed to be mainly localized in the γ-aminobutyric acid moiety, suggesting that glutamic acid might be a fairly direct precursor of the moiety. By the method employed, DL-glutamic acid-1-14C was not significantly incorporated into variotin. It was demonstrated that L-glutamic acid was converted to γ-aminobutyric acid in the presence of acetone-dried cells of Paecilomyces varioti. These results indicated that decarboxylation of glutamic acid was involved in the formation of variotin. The incorporation yield was decreased when DL-glutamic acid-3, 4-14C was introduced into the culture in the late stage of variotin formation.
The colonies of Aspergillus niger and Penicillium urticae were grown on cellophane membranes placed on agar media, and paraffin sections of the isolated colonies were examined comparatively by cytochemical methods. Hyphal cells showing high degree of basophilia were located mainly in the growing outer region, especially in the surface layer, of the colonies. The basophilic substances present in the surface layer of the outer region seemed to move into fruiting bodies that reproduce conidia. Fruiting bodies located in the outer region were the most basophilic of all parts of the colonies, whereas those in the central region were less or not basophilic; most of the basophilic substances might have been transferred into the condia from these bodies. A metachromatic substance, which is considered to be polyphosphate, was highly concentrated in the fruiting bodies in granular forms. This substance was also transferred into the conidia as the colonies developed. In general, no essential difference was observed between the colonies of the two fungi tested.
The general type of transduction of Bacillus subtilis Marburg strain with the phage S-1 was studied. The transducing phage of S-1 seemed to be a defective one as those of P1 in E. coli and P22 in Salmonella (5, 6). The phage S-1 was found to have a killing ability toward group 2 recipient bacteria, which did not allow the multiplication of S-1. This might be explained mainly by the multiple infection of active and transducing phages. The stimulation of transduction with the ultraviolet-light irradiated phage, however, could not be considered on the same basis, because the extent of the stimulation is diverse in the different lines of the recipient bacteria, and there is no coordination between the per cent of killing of the phage with ultraviolet irradiation and that of stimulation of the transduction by the UV-phage. Possible causes for this phenomenon are discussed.
(1)It was experimentally shown that the pattern of angular distribution of light scattered by moderately large microbial cells is roughly presented by the FRAUNHOFER diffraction theory for a circular slit. (2) When a parallel beam is used as the incident rays, cuvettes of usual size give, however, smoothed scattering pattern due to the finite effective volume of scattering centre. The light was shown still to be strongly scattered as theoretically expected into the forward direction. (3) Practically all the scattered light could therefore, be collected by using a light receiver with a large aperture placed close to a thin cuvette. providing thus a convenient method of obtaining the true absorption spectra of cell suspensions. (4) In accordance with RAYLEIGH-GANS' first approximation to the cross section of microbial cells of moderate size, the total extinction is given by the sum of scattering and absorption attenuation. A true scattering spectra, therefore, could be obtained as the difference of the extinction spectra observed with a usual narrow beam spectrophotometer and the true absorption spectra obtained by use of a wide angle apparatus such as the one mentioned above. (5) Even in the case of fairly high-populated suspension of Chlorella, the observed apparent absorption spectra are mostly due to scattering loss. The local feature of the curves reflects the mode of anomalous dispersion of the real part of refractive indices of cells. (6) A slow rise experienced in the spectrum of yeast at 450mμ is also mainly due to scattering interference and partly to the existence of anomalous dispersion of refractive indices. In the single scattering region, the absorption of cell contributes to the attenuation only through modifying the real part of refractive index and not directly through its imaginary part.
Since spores of Aspergillus niger require L-alanine specifically for the initiation of germination, the role of alanine in this respect was investigated using alanine-C14 as a tracer. The radioactive alanine was actively incorporated into spores during germination after a short lag of about 30min. The alanine once incorporated was immediately deaminated resulting in the formation of ammonia and pyruvate, which in turn was gradually decarboxylated with the evolution of CO2. The radioactivity of incorporated alanine-C14 was readily distributed to various fractions of germinating spores, especially to protein and nucleic acids. In this case, pyruvate, CO2 and probably ammonia derived from alanine seem to supply building blocks for the construction of these macromolecular substances in the early phase of germination. The observation that the base composition of ribonucleic acid changed markedly in the early germination implies that those metabolites of alanine involve in the modification of nucleic acid molecules; such event occurring in the early phase is considered to be a prerequisite for the initiation of germination.
Several nutritional conditions were tested for their capacity to synchronize the segmentation of filamentous cells of Lactobacillus delbrueckii produced by growth under vitamin B12 deficiency. A medium containing adenine, guanine, uracil, vitamin B2, B12, folic acid, niacin, and pantothenic acid, beside glucose, amino acid, and inorganic salts was found to be most effective in synchronizing the segmentation of filamentous cells which was not followed by separation and growth of daughter cells. Cytological observations disclosed that the segmentation of filamentous cells in this medium was preceded by an increase in stainability with HCl-Giemsa and the rearrangement in cells of nuclear bodies.
1. The activity to synthesize aspartic acid from fumaric acid and ammonia and the activity to synthesize glutamic acid from citric acid and ammonia were examined with the cell-free extracts obtained from several strains of M. glutamicus and their mutants grown on glucose bouillon media. All of them were found to possess a strong activity of the latter but practically no activity of the former. 2. The activities of aspartase, glutamic dehydrogenase, alanine dehydrogenase, leucine dehyrogenase, glutamic-aspartic transaminase, and glutamic-alanine transaminase were examined with the cell-free extracts obtained from the cells of M. glutamicus (parent strain) grown on different levels of biotin. Only glutamic dehydrogenase and transaminases were detected in ample amounts. No significant difference was found in the activities of enzymes involved in the ammonia uptake in the extracts of the cells grown on the different levels of biotin. 3. From the results 1 and 2, it is concluded that in M. glutamicus the principal mechanism of ammonia uptake is effected by TPN-linked glutamic dehydrogenase irrespective of the biotin level in the growth medium, and consequently, the biosynthesis of the amino acids belonging to glutamic acid family and aspartic acid family proceeds directly or indirectly via the synthesis of glutamic acid.
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