A convenient method was proposed for the estimation of glucosamine content in koji. In this method, the time of acid hydrolysis of the mold sample was markedly shortened modifying the previously reported method as follows; the mold sample was immersed in 60% of sulfuric acid for 24 hr at 25°C, and then the mixture was diluted with water to make the concentration of sulforis acid 1 N and autoclaved under the pressure at 1kg/cm² for 1 hr. The liberated glucosamine was assayed by Blix's method. The glucosamine contents of mycelia obtained from the submerged and surface cultures were increased about 2 times of initial stages in prolonged incubation. The significant differences of the glucosamine contents in various kojis were seen depending on the raw materials used; the values were 18_??_26mg/g in wheat bran koji and 6_??_16mg/g in rice and defatted soybean meal koji.

View full abstract

The cell-free extract of Aspergillus niger (AKU 3302) catalyzed the degradation of nicotinamide mononucleotide to an unidentified compound. This compound was isolated from the reaction mixture and identified as nicotinic acid ribonucleoside (NAR). When the mold was cultured on media containing nicotinic acid- and nicotinamide-¹⁴C, the ratio of radioactivity incorporated into NAR was 16 and 10% of the total activity in the mycelial extracts, respectively.

View full abstract

A large fluorescence enhancement of 2-p-toluidinylnaphthalene-6-sulfonate (TNS) caused by amylose decreases as the substrate is degraded by amylases. This property was used to follow the enzymatic hydrolysis of amylose and analyze the action pattern of six kinds of amylases. This method can substitute the conventional blue value method, and is more sensitive for short chain amylodextrins. The advantage of the new method over the blue value method is that it is useful to monitor the hydrolysis of maltooligosaccharides to which the blue value method cannot be applicable, and that it enables continuous monitoring of the enzyme reactions.

View full abstract

The content of total cellular lipid of Candida tropicalis grown on a mixture of n-alkanes (C₁₀-C₁₃) was about 20% of the dry cell weight at the exponential growth phase and 14% at the early stationary phase. Phospholipid corresponded to approximately 70% of the total lipid independent of the growth phases. The composition of cellular lipid classes did not change significantly during the growth. On the other hand, a drastic time-course change in fatty acid composition was observed. The proportion of odd-chain fatty acids, one of the most specific cellular components of the yeast grown on the n-alkane mixture, increased in both phospholipid and triglyceride along with the yeast growth. In the meantime, the proportion of polyunsaturated fatty acids varied markedly during the course of cultivation, showing a peak at the early growth phase. The high content of polyunsaturated fatty acids at the early stages of growth correlated to the contents of these acids in phospholipid rather than in triglyceride.

View full abstract

Conditions for accumulation of guanosine polyphosphates-guanosine 3'-diphosphate, 5'-monophosphate (G3P), guanosine 3'-diphosphate, 5'-diphosphate (MSI), guanosine 3'-diphosphate, 5'-triphosphate (MSII)-by microbial conversion of 5'GMP using a mutant KY 13510 derived from Brevibacterium ammoniagenes ATCC 6872 were investigated. Optimum pH and temperature were 7.4 and 33 to 37°C, respectively. As the substrate, 5'XMP, 5'GMP, 5'GDP and 5'GTP gave similar results in the accumulation, and 5'GDP and 5'GTP did not specifically stimulate the accumulation of MSI and MSII. The concentration of phosphate and magnesium salt in reaction mixture was important, and relatively high levels of the both salts were stimulative for the accumulation. From the time course of the reaction, it was indicated that 5'GMP was first converted to 5'GDP and 5'GTP and then to MSI and MSII. By comparison of conversion activity of the strains, it was shown that the nucleotides degrading activity reduced the whole conversion rate. The practical procedure for the production of the guanosine polyphosphates was represented, which resulted in accumulation of more than 12g of MSI and 5g of MSII from 30g of 5'GMP•Na₂•7H₂O per liter.

View full abstract

The acidic and basic subunits are the main constituents of soybean 11S globulin. Each of these two subunits consists of three major polypeptides of similar size. The molecular weights of the acidic and basic subunits have been previously estimated to be 37, 000 and 22, 000, respectively, by SDS-polyacrylamide gel electrophoresis (Catsimpoolas et al., J. Sci. Food. Agric., 22, 448 (1971)). Reevaluation of the molecular weights by 6M guanidine gel chromatography gave the values of 28, 000 and 18, 000, respectively. These are supported by results of equilibrium sedimentation in the same solvent. The previously reported values seem to have been overestimated, especially for the acidic subunits. The overestimations seem to be related to the high percentage of acidic amino acids, which causes the conformation of the SDS-protein polypeptide complexes of these subunits to deviate from those of proteins usually employed as standards for molecular weight estimations.

View full abstract

A mutant of Sclerotinia libertiana Fuckel sometimes though seldom, restored the ability to form sclerotia when grown at a low temperature, 15_??_20°C, on potato medium. There appeared to be a correlation between the regulation of vegetative growth and accumulation of precursors of melanine pigments. The effects of various factors on the morphogenesis were investigated using Czapek-Dox medium with or without addition of amino acids. A combination of Sclerin (SCL) and thiol reagents stimulated melanogenesis in the presence of amino acids at a low temperature. While, cyclic adenosine 3', 5'-monophosphate (cyclic AMP) alone stimulated the melanogenesis without addition of the amino acids. Also, a combination of SCL and cyclic AMP or 3, 4-dihydroxyphenylalanine (DOPA) induced the formation of sclerotium-like hyphal aggregates though not normal sclerotia.

View full abstract

Pepsidine hydrolase, which was produced by Bacillus pumilus EF49-210 and catalyzed the two-step hydrolysis of pepsidines, was purified by means of ammonium sulfate precipitation, DEAE-Sephadex column chromatography and Sephadex G-200 and Sepharose 6 B gel filtrations. The purified enzyme was homogeneous in disc electrophoresis and the ratio of the deacylating activity to the valine-splitting activity remained almost unchanged throughout the purification processes, showing that both activities were inherent in the enzyme.
The substrate specificity of the purified enzyme showed the enzyme to be a kind of aminopeptidase. The molecular weight of the enzyme was calculated to be 320, 000. The enzyme consisted of two identical subunits and showed the maximum activities at pH 7.5 on both activities.

View full abstract

Oerskovia sp. CK produced three types of β-1, 3-glucanases designated as F-L, F-0 and F-2. F-L showed high lytic activity to viable yeast cells and weak activity to yeast glucan. F-0 and F-2 had little or no lytic activity and strong β-1, 3-glucanase activity.
F-0 or F-2 showed high lytic activities to yeast cells pretreated with small amounts of F-L which did not lysed the cells. Lytic activity of F-0 or F-2 also increased when cells were treated with alkaline pH or with both reducing agents and pH.
From these results, it is supposed that the ineffectiveness of F-0 or F-2 on the lysis of yeast cells might be attributed to a spatial inaccessibility of enzymes to the yeast glucan layer. However, the treatment of F-L, alkaline pH and reducing agents would bring about a modification of cells to give F-0 or F-2 access to the wall glucan and consequently the lysis of cells would occur.

View full abstract

Unlike technical grade yeast RNA, which was confirmed to contain several per cent of 2'-5' phosphodiester linkages, RNA prepared from different kinds of commercial yeast in a cold room consisted exclusively of 3'-5' phosphodiester linkages. Heat treatment of the 3'-5' linked RNA solution resulted in partial isomerization of the internucleotide linkage of the polynucleotide chain (C_3'-C_5'→C_2'-C_5'). The isomerization of RNA occurred in the presence of water, at high temperature, and under acidic conditions. Treatment of dry RNA at 100°C for 2 hr did not result in any detectable isomerization. The isomerization was actually observed in yeast RNA when yeast cells suspended in sodium chloride solution were heated. It is concluded therefore that 2'-5' phosphodiester linkages found in technical grade RNA had been formed neither at a step of precipitating RNA with acid nor at a step of drying RNA, but had been formed at a step of heat extraction of RNA from yeast. When 0.1% poly (A) solution, pH 4.8, was heated for 20 hr in a boiling water bath, the isomerization proceeded during the first 6 hr, and finally reached about 37%, irrespective of chain length.

View full abstract

Isolation of thermophilic hydrogen bacteria was performed at 50°C using enrichment culture method. One of the four strains isolated, strain TH-1 grew most rapidly. Culture conditions of strain TH-1 were investigated. Optimum temperature and pH for growth proved to be 52°C and 7.0, respectively. There existed a positive correlation between the specific growth rate and the partial pressure of carbon dioxide in the gas phase. Ammonium and nitrate are the good nitrogen sources in that order. Effect of concentrations of nitrogen source, magnesium, ferrous and phosphate ions on the cell growth was also investigated. The maximum specific growth rate (μ_max) of strain TH-1 was determined as 0.68 hr^-1 by the cultivation at 52°C in a jar fermentor containing the optimal medium at pH 7.0.

View full abstract

Starting from (Z)-13-trimethylsilyl-9-tridecen-12-yn-1-ol (IVa), (±)-dendrotrifidiol (Ia), a new antifungal polyacetylenic compound from Dendropanax trifidus Makino, was first synthesized together with methyl (±) dendrotrifidate (Ic) and dendrotrifiolone acetate (IId). Their interconversions, stabilities and characteristic UV spectra are also discussed. Antifungal activities of synthetic racemic products were a little lower than those of optically active natural products.

View full abstract

Interaction of α_S1-κ-casein complex with Ca²⁺, Ba²⁺, Mg²⁺ and Sr²⁺ was investigated. On the addition of 0 to 11mM of these ions, the sedimentation coefficients of α_S1-κ-casein complex increased gradually with the rise of concentration of the ions. On the addition of more than 11mM of Ca²⁺ and Ba²⁺, a new peak with a higher sedimentation coefficient (large aggregate) appeared, while such a new peak did not appear on the addition of Mg²⁺ and Sr²⁺. The amounts of Ca²⁺ and Ba²⁺ bound to α_S1-κ-casein complex were higher than those of bound Mg²⁺ and Sr²⁺. An apparant partial specific volume of α_S1-κ-casein complex decreased remarkably on the addition of more than 11 mM of Ca⁺², while it decreased only slightly on the addition of the same concentration of Mg²⁺ Stable α_S1-κ-casein micelles were formed by Ca²⁺ and Ba²⁺, but not by Mg²⁺ and Sr²⁺. From the above results, it is suggested that the formation of the large aggregate of α_S1-κ-casein complex is essential for the formation of the stable casein micelles.

View full abstract