Radioactive starch was digested with crystalline Taka-amylase A and the incorporation of the radioactivity into the enzyme crystal was investigated under various conditions. The incorporated radioactive sugar seems to be polysaccharide in nature and, though this radioactive sugar could not be removed by various purifying procedures, it was released from the protein part by boiling or paper-electrophoresis. Possible implications of this incorporation was discussed.
In order to systematize the descriptive terms of the conidial walls, which are one of the essential characteristics in the taxonomy of the Aspergilli, the author classified the micromorphological characteristics of the conidia as observed with an electron microscope.
(1) The authors studied the oxidation of D-glucose, D-fructose, D-mannose, D-galactose, D-xylose, and L-arabinose by surface and shaking cultures of Gluconoacetobacter liquefaciens. (2) The production of organic acids from these sugars was studied by paper chromatographic techniques and 8 spots from D-glucose, one spot from D-fructose, D-mannose, D-galactose, 3 spots from D-xylose, 2 spots from L-arabinose were detected on the paper chromatograms. The production of D-mannonic acid from D-mannose, D-galactonic acid from D-galactose, D-xylonic acid from D-xylose, and L-arabonic acid from L-arabinose were assumed. (3) The oxidation of glucose was studied in detail. When CaCO3 was not added to the shaking culture, glucose was oxidized very slowly. When CaCO3 was added to the shaking culture, glucose was oxidized rapidly and the organic acid with the RF value of 0.02 was produced at first and then the production of organic acids with the RF, values of 0.22-0.25, 0.33-0.35, 0.43-0.47, 0.60-0.65, and 0.90 followed. Three spots with the RF values of 0.02, 0.47-0.50, and 0.60-0.65 were detected with ferric chloride solution. (4) Isolation and identification of oxidative products from glucose were tried. Aldehyde, formic-, acetic-, 5-keto-D-gluconic-, glycolic-, and tartronic acid, other unknown reducing acids and three substances which gave reddish violet color reactions were isolated from the culture liquid by shaking culture. (5) Three substances of positive ferric chloride reaction were isolated as crystals, showing the melting point of 203.5°, 230° and 275°, respectively. All of them were recognized as γ-pyrone compounds and the former two were recognized as new substances. Since these γ-pyrone compounds were found to be produced by other oxidative bacteria, for example by Acetobacter 1955 Studies on Oxidative Fermentation. I. 29 melanogenum, which produced reddish brown pigment in the fermentation liquor, these new substances were named "Rubiginol" and "Rubiginic acid" ("rubiginosus" means" reddish brown"). (6) These three γ-pyrone compounds were found to be produced from D-glucose by Gluconoacetobacter liquefaciens when it was incubated by shaking culture with the addition of CaCO3, but not without CaCO3. They were not produced from glucose by surface culture both with and without CaCO3. From D-fructose, D-mannose, D-galactose, D-xylose, and L-arabinose, we could not find the formation of the substances of positive ferric chloride reaction both in shaking and in surface culture.
In the previous report, the authors found the formation of three substances which gave reddish violet color reactions with ferric chloride in the metabolic products of glucose by Gluconoacetobarter liquefaciens. One of them was found to be a new γ-pyrone derivative and was named as rubiginol. Its chemical properties was studied and the chemical structure was confirmed to be 3, 5-dihydroxy-1, 4-pyrone.
Pectic glycosidases produced by a strain of Aspergillus niger comprise at least two kinds of polygalacturonases, each of which is formed in different ways depending on the culture conditions, especially on the kinds of C-sources. The one, depolymeric polygalacturonase (DPG), produced constitutively by the mold, attacks the polygalacturonase chain at random, reducing the molecular size rapidly, and leaving tri-, di- and D-galacturonic acids as end products in the final reaction mixture where more than 50% of the substrate is hardly hydrolyzed. This enzyme was effectively purified by adsorption onto pulpified filter paper, followed by the general method of precipitation, from the culture liquor which did not contain pectic substrate and other adaptive pectic enzymes. DPG is easily adsorbed in a salt-free state at a pH near 4 and eluted with a more neutral salt-solution. The reaction pH has the optimum value of 3.4-4.6, variable with the substrate and with the method of determination. DPG is most stable at pH 3.6, where the half activity is reduced by treatment at 50° for 1hour. This enzyme seems to hydrolyze the non methoxylated glycosidic chain. The another polygalacturonase, galacturonogenic polygalacturonase (GPG), the formation of which is induced by the pectic substrate in contrast to DPG, splits the terminal galacturonic acid from one end of the polygalacturonide chain, not reducing the molecular size of the substrate as rapidly as DPG does. Other properties of GPG are similar to those of DPG though there are some differences which might be due to the lesser purity.
Using Pseudomonas incognita strain 3L aerobic and anaerobic decomposition of L-(+)-tartarate was investigated. Succinic and acetic acids were isolated and identified as the anaerobic decomposition products of tartarate by resting cells. Furthermore, from the balance studies it was clearly established that anaerobic decomposition of tartarate is performed according to eq. (3). In order to clarify the mechanism of this reaction, anaerobic decomposition of tartarate by resting cells was conducted in the presence of radioactive bicarbonate and the incorporation of C14O2 into various compounds was examined. From the experimental results two schemes (Scheme I and II.) were proposed to explain the observed incorporations of the isotope. But the following experimental results excluded the possibility of Scheme I as the main path of the anaerobic decomposition of tartarate by this organism. (1) D-(-)-Phosphoglycerate was decomposed anaerobically and about 1 molecule of CO2 was evolved per molecule of phosphoglycerate consumed, while 1/3 molecule of CO2 should be expected if this compound were metabolized according to Scheme I. Therefore CO2 fixation reaction according to Scheme I did not occur under these conditions. From the thermodynamic point of view, the CO2 fixation reaction according to Scheme I may be performed more easily when phosphoglycerate rather than tartarate is the substrate. Therefore this experimental result makes Scheme I unlikely. (2) Similarly succinate formation by the CO2 fixation reaction was not observed in the anaerobic decomposition of pyruvate, (3) NaF, in the final concentration of M/600, completely inhibited the decomposition of phosphoglycerate, whereas the decomposition of tartarate was not inhibited in the same concentration. Therefore phoshoglycerate was excluded as the intermediate. (4) Anaerobically, DL-glcerate was not metabolized by this organism and is not likely to be the intermediate.
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Edited and published by : Applied Microbiology, Molecular and Cellular Biosciences Research Foundation/Center for Academic Publications Japan Produced and listed by : TERRAPUB, Center for Academic Publications Japan/Shobi Printing Co., Ltd. (-Vol.60,No12), Center for Academic Publications Japan/InternationalAcademic Printing Co., Ltd.(-Vol.54,No1)