Two hundred and fourteen strains of the Aspergillus were cultured both in agar slants and in a liquid medium by shaking, and the productivity of aflatoxins was studied, respectively, by observation of the fluorescence of the medium and by fluorometry and thin-layer chromatography, using the aflatoxin-producing strain ATCC 15517 as a control. In the slant culture of Czapek agar, only a few strains showed the stronger blue or green fluorescence than that of the control strain. Statistically, in the yellow-green-spored Aspergillus, certain mycological characters were seemed to be closely associated with the productivity of fluorescence. When the chloroform solutions of the yellow-green-spored Aspergillus, prepared from the shake-cultured broth by the same preparation method as that of aflatoxin, were analyzed fluorometrically, none was found to have the same excitation wavelength as that of control in the blue fluorescence; on the contrary, in the green fluorescence, the majority of strains showed both the same excitation wavelength and emission wavelength as those of control. On thin-layer chromatograms, there were spots corresponding to aflatoxins, but they were quite different from aflatoxins as will be reported in Part 2.
The distribution of deaminases active for adenosine compounds was studied and it was found that besides two kinds of deaminases, i.e., non-specific ATP and adenosine deaminases, another acid-type ADP-deaminating enzyme was present in Aspergillus species. Deaminases from Aspergillus glaucus and A. repens were purified and it was confirmed that they were of the same type of non-specific ATP deaminase which was found in Microsporum audouini by the authors. Non-specific acid ADP-deaminating enzymes were found and purified from the koji cultures of both A. ochraceus and A. melleus. They deaminate ADP, ATP, adenosine sulfate, adenosine tetraphoshate, 5′-AMP, dAMP, 3′, 5′-cyclic AMP, adenosine, and 3′-AMP in this order. The optimum pH of ADP-deaminating enzyme obtained from both strains were 3.4 in acetate buffer, and the Km values of A. ochraceus and A. melleus were calculated to be 4.0×10-5M and 6.6×10-5M, respectively.
Seven homoserine, 42 methionine, 42 threonine, and 15 isoleucine auxotrophs were obtained from Brevibacterium flavum No. 2247 (ATCC No. 14067) by X-ray irradiation and N-methyl-N′-nitro-N-nitrosoguanidine treatment. Concerning the L-lysine-producing ability, the homoserine auxotrophs were the best and about one-half of the threonine auxotrophs ranked next. The rest of threonine auxotrophs and all of the methionine and isoleucine auxotrophs produced little of L-lysine. Investigation on enzyme activities of threonine synthesis revealed that L-lysine-producing threonine auxotrophs lacked homoserine kinase and accumulated the substrate, L-homoserine. On the other hand, the rest which produced little L-lysine and fairly much phosphohomoserine last the threonine synthase activity.
Te content in staphylococcal cells was determined by activation analysis. Tellurite uptake took place primarily in the cytoplasm of the cell. Staphylococcal tellurite uptake, as determined by activation analysis, varied in different strains but could not be used as a means to differentiate species. Staphylococcal uptake could not be directly correlated with their ability to grow on TGA and produce observed differences in blackness of colonies.
Inosine formation by mutants of Bacillus subtilis in chemically defined medium was investigated, using strains No. 11413 (adenine-histidine-requiring) and No. 11023-4 (adenine-requiring). Only adenine (or its congeners) was able to regulate the formation of inosine in the growing culture, and it was also found that adenine was a specific requirement for inhibition of inosine formation by non- growing washed cells of these mutants. Purines other than adenine, pyrimidines, and amino acids were all inactive in inhibitory effect on inosine formation by these washed cells. However, the optimum concentration of adenine for the nucleoside formation in growing culture was greatly altered by certain substances. AICA and amino acid mixture(artificial L-amino acid mixture of "casamino acids" type) were found to have a strong adenine-sparing action, while AICA-R, L-histidine, purines, etc., had no such action. AICA inhibited adenine deamination reaction of the intact cells in some cases, which might be one of the mechanisms of the sparing action of the amine. On the other hand, effect of the amino acid mixture on the deamination reaction was not clear under the conditions examined. Another significant effect of the amino acid mixture was its promotive action on the cell growth accompanied with a marked increase in the amount of inosine produced. AICA and some purine compounds were slightly stimulative, but far less than the amino acid mixture in the stimulation of the production.
Conditions for the induction of the ascogonium in Gaeumannomycesgraminis (SACC.) von Arx et Olivier are defined and the various stages of development of this reproductive structure are illustrated as well as in Neurospora crassa Shear et Dodge. Under the influence of certain physical and chemical factors, both these organisms differentiate hyphal structures with loose coil which may correspond to abnormal ascogonia.
Institute of Applied Microbiology, University of Tokyo, Bunkyo-ku, Tokyo (Received October 26, 1967) The transfer of host specificity by conjugation from one rhizobial species to the other was studied. Rhizobium trifolii and Rh. phaseoli were mixed-cultured in yeast extract-mannitol medium and then the former was eliminated completely from the culture by the action of Rh. trifolii-specific phage. Cells remained survived in the culture (strain W1, progeny of Rh. phaseoli) was examined for the clover infectivity as determined by the formation of infection threads in root hairs of clover plants. Strain W1 clearly showed the clover infectivity, but it retained various physiological and immunological characteristics of Rh. phaseoli. When Rh. trifolii and strain W1 were cultured in the presence of acridine orange, which is known to eliminate episomic factors in bacterial cells, a marked decrease in infective activity on clover plants was demonstrated. The present observations strongly support the view that the host specificity in rhizobia is mediated by an episome-like factor just like as the drug resistance factor in bacteria, although the evidence is lacked in that the factor could be integrated into the chromosome.