The biological activities of zinc and cadmium on Euglena gracilis grown in zinc deficient and sufficient media were examined. Cadmium was neither involved in the normal cell meta-bolism of E. gracilis under zinc deficient conditions, nor did not replace zinc, which is essential for the normal growth. More cadmium was incorporated into cells grown in zinc deficient media than in zinc sufficient ones, resulting in more toxic effects in zinc deficient media than in zinc sufficient ones. Cadmium effectively provoked abnormal cells under zinc deficient con-ditions, suggesting that the normal process of cell division was interrupted by cadmium.

View full abstract

The physico-chemical properties of the purified glucose isomerases [D-xylose ketol iso-merase, EC 5. 3. 1. 5] of Streptomyces olivochrornogenes and Bacillus stearothermophilus were examined. The molecular size and shape of both enzymes were similar. The molecular weights, sedimentation coefficients, partial specific volumes, diffusion constants and Stokes' radii of the Streptomyces and Bacillus enzymes were determined to be 120, 000 and 130, 000, 7.55 S and 9.35 S, 0.725 and 0.736ml/g, 5.87×10^-7 and 6.82×10^-7cm²/sec, and 51 and 53 Å, respectively. The Streptomyces glucose isomerase was found to consist of two subunits, each having a molecular weight of 56, 000. Large differences were found in the amino acid composi-tions of these two enzymes, especially in their serine, proline, tyrosine, lysine and arginine contents. The enzymatic properties of both these purified glucose isomerases were also examined, and it was seen that they both displayed activity on D-xylose, D-xylulose, D-glucose, D-fructose, D-arabinose and D-ribose. The smaller Km values and the larger molecular ac-tivities for D-xylose and D-xylulose indicated that both enzymes are essentially D-xylose iso-merases. The optimum temperature was 80°C for both enzymes. The optimum pH was 8 to 10 for the Streptomyces enzymes and 7.5 to 8.0 for the Bacillus enzyme. The Bacillus enzyme was more thermostable than the Streptomyces enzyme, but required cobalt ions in addition to magnesium ions for the full expression of its activity.

View full abstract

It was found that minor components were approximately 1% of the total deoxyribosides in the analysis for base composition of chick embryo DNA. In order to identify the minor components, this work was done. The separation of the minor components from the major components in a DNA hydrolysate was carried out by celite column chromatography and the final purification was accomplished by paper chromatography. For detection of minor com-ponents at the deoxyriboside level, the microbial assay method with Lactobacillus leichmannii ATCC 7830 was applied. Thus, two minor deoxyribosides of the DNA were identical with deoxyuridine and 5-methyldeoxycytidine in spectral, electrophoretic and chromatographic properties, respectively. Furthermore, uracil and 5-methylcytosine were purified and identi-fied from perchloric acid hydrolysate of the DNA.

View full abstract

Glucoamylase I (MW 90, 000; N-terminal alanine) was selectively produced by a sub-merged culture of Aspergillus awamori var. kawachi as an enzyme having the ability to digest even raw starches, and was converted into a modified active glucoamylase decreasing in mole-cular weight during the digestion with the acid protease of the same mold strain. The modified glucoamylase (MW 83, 000; N-terminal alanine plus isoleucine) was resembled to an inter-mediate type of glucoamylase I', and exhibited hydrolysis curves for gelatinized potato starch and maltose in the same manner as that of glucoamylase I; but it did not digest raw starches and was not adsorbed onto cornstarch, and showed the lower hydrolysis limit of 80 percent for glycogen. The carbohydrate contents of glucoamylase I decreased 59 percent during the digestion with fungal α-mannosidase. The carbohydrate-split glucoamylase (MW 86, 000; N-terminal alanine) was unstable at pH 9 or at 65°C in the same extent as glucoamylase I', but was identical with glucoamylase I in the hydrolysis curves for various substrates, the digestibility for raw starches and the adsorbability onto cornstarch. Multiple forms of glucoamylase were observed when native glucoamylase I was degraded stepwisely with fungal acid protease and α-mannosidase.

View full abstract

Ipomeamarone, a furanosesquiterpenoid produced in Ceratocystis fimbriata-infected sweet potato root tissue, was decomposed by neither sweet potato strain nor oak strain of C. fimbriata. Ipomeamarone inhibited various physiological events of C. fimbriata such as endo-conidial germination, germ-tube growth, mycelial growth, endoconidial formation, black coloration of mycelia and normal morphological development of mycelia. The inhibitory effects were not so severe in sweet potato strain, pathogenic to sweet potato, compared with oak strain, non-pathogenic one.

View full abstract

The following ten new analogs of neohesperidin dihydrochalcone (DHC) (I) were synthe-sized: Hesperetin DHC-4'-β-L-glucopyranoside (II), hesperetin DHC-4'-[2-O-methyl-β-D-glucopyranoside] (III), hesperetin DHC-4'-[3-O-methyl-β-D-glucopyranoside] (IV), hesperetin DHC-4'-[6-O-methyl-β-D-glucopyranoside] (V), hesperetin DHC-4'-β-D-glucopyranosiduronic acid (VI), hesperetin DHC-4'-β-maltotrioside (VII), hesperetin DHC-4'-[β-L-glucopyranosyl-(1→2)-β-D-glucopyranoside] (VIII), 3, 2', 4'-trihydroxy-4-methoxydihydrochalcone-4'-[β-L-rhamnopyranosyl-(1→2)-β-D-galactopyranoside] (IX), 3, 4'-dihydroxy-4-methoxydihydrochal-cone-4'-[β-L-rhamnopyranosyl-(1→2)-β-D-galactopyranoside] (X) and 4, 2', 4'-trihydroxydihy-drochalcone-4'-[β-L-rhamnopyranosyl-(1→2)-β-D-galactopyranoside] (XI).
Compounds II, III, IV, V, VII, VIII, IX, and X are 0.8, 2.0, 0.8, 4.0, 1.4, 0.02, 4.5 and 0.004 times as sweet as saccharin, respectively, while VI and XI are tasteless.

View full abstract

The levels of guanosine 3', 5'-monophosphate (cGMP)-dependent protein kinase in the larval and pupal tissues of Bombyx mori were estimated. This activity was highest in the fat body of the female pupa. The enzyme showed a significant variation in activity during devel-opment of adult in female. Male silkworm gave less significant results. The cGMP-de-pendent kinase partially purified from the pupa could be activated by a high concentration of adenosine 3', 5'-monophosphate (cAMP) as reported for cGMP-dependent protein kinases from other sources. The nature of the enzyme thus activated and that of the enzyme activated by a low concentration of cGMP were found to be similar in several aspects. This indicates that the intrinsic activity of protein kinase from the silkworm pupa is independent of the kind of cyclic nucleotide as an activator.

View full abstract

It was shown that reduction of the disulfide bonds of the sonicated α-ovomucin by thiol reagent produced polypeptide chains of smaller size in 3 M NaCl, 3_??_6M guanidine hydro-chloride and 1% SDS solutions. It was also found that monomeric α-ovomucin tended to dimerize in 0.1M salt solution.
Little change in molecular size of the sonicated β-ovomucin was found to result from reduction of the disulfide bonds.
Sedimentation equilibrium gave 1.8×10⁵ for the molecular weight of S-carboxymethylated α-ovomucin and 4.0×10⁵ for that of β-ovomucin.

View full abstract

The dispersion mechanism in gel chromatography of proteins was quantitatively studied on the basis of a dispersion model which gave consideration to the contribution of gel phase dif-fusion and longitudinal dispersion in a column. Particularly, the effect of gel phase diffusion was examined in detail by comparing the values determined by applying the moment analysis to the elution curve and those obtained for a single gel bead.
When the distribution coefficient of solute was small and the particle size of gel was large, the elution curve was asymmetrical and had a prolonged tail of low concentration. The gel phase diffusion coefficient determined from the elution curve was much higher than that for a single gel bead owing to the effect of the tail. This suggested that only a small portion near the gel bead surface was accessible to most of the solute applied owing to the much lower diffusion velocity in gel than the superficial velocity. The column efficiency improved as compared with the theoretical result because of the apparent increase in gel phase diffusion coefficient. On the other hand, in the case of large distribution coefficient and small particle size, the actual column efficiency was lower than the theoretical as seen in our previous study on the dispersion of low-molecular substances.
Furthermore, the elution curves were numerically calculated on the basis of the disper-sion model to examine the validity of the values of the gel phase diffusion coefficient and the longitudinal dispersion coefficient. The agreement of the calculated elution curves with the experimental ones suggested that the dispersion model was applicable to gel chromatography of proteins as well as that of low-molecular substances.

View full abstract

An α-glucosidase and a glucoamylase have been isolated from fruit bodies of Lentinus edodes (Berk.) Sing., by a procedure including fractionation with ammonium sulfate, DEAE-cellulose column chromatography, and preparative gel electrofocusing. Both of them were homogeneous on gel electrofocusing and ultracentrifugation. The molecular weight of α-glucosidase and glucoamylase was 51, 000 and 55, 000, respectively. The α-glucosidase hydro-lyzed maltose, maltotriose, phenyl α-maltoside, amylose, and soluble starch, but did not act on sucrose. The glucoamylase hydrolyzed maltose, maltotriose, phenyl α-maltoside, soluble starch, amylose, amylopectin, and glycogen, glucose being the sole product formed in the digests of these substrates. Both enzymes hydrolyzed phenyl α-maltoside into glucose and phenyl α-glucoside. The glucoamylase hydrolyzed soluble starch, amylose, amylopectin, and glycogen, converting them almost completely into glucose. It was found that β-glucose was liberated from amylose by the action of glucoamylase, while α-glucose was produced by the α-glucosidase.
Maltotriose was the main α-glucosyltransfer product formed from maltose by the α-glucosidase.

View full abstract

A major glycoprotein, CB-7+8 component, was selectively precipitated by dialyzing the fraction extracted with 1M KCl from the delipidated milk fat globule membrane against deionized water. The CB-7+8 contained 4.16% hexoses, 2.05% hexosamines and 2.08 sialic acid.
The CB-7+8 component was observed to be able to associate with the constituent poly-peptides of the soluble glycoprotein, PAS-I_??_VII and CB-III, and to form a soluble complex.
The CB-7+8 component which gave an apparently asymmetrical monopeak on sodium dodecyl sulfate-polyacrylamide gel electrophoresis showed remarkable heterogeneity on iso-electric focusing, and six major bands of pI ranging from 5.9 to 6.8 were observed. The results of digestion of CB-7+8 with neuraminidase suggested that this heterogeneity was due to the microheterogeneity of oligosaccharide chains having a variable number of sialic acid residues.

View full abstract

Some biological aspects of radiosensitization of microorganisms by NaCl at compara-tively higher concentrations were studied. Among different strains of bacteria and yeasts, the radioresistant vegetative form was particularly sensitive to NaCl present during irradiations. With E. coli, such radiosensitizing effect of NaCl was abolished by mutations at the pol and rec loci or by the addition of certain solutes at the time of irradiation. The effective extra-cellular chloride concentrations for E. coli B/r were not less than 0.1M. When actinomycin D and chloramphenicol were added during reincubation of E. coli B/r following irradiation in the presence of NaCl, the radiation lethal effect was enhanced, the extent of which was almost independent of doses of irradiation. From these results together with the previous data, the basic mechanism for NaCl radiosensitization was discussed with special references to a possible role of C1₂ radical anions as attacking species and to the inhibition of pol- and rec-de-pendent DNA repair systems as the primary cellular damage.

View full abstract

Damages in macromolecular components and in their functions of E. coli produced by gamma irradiation in the presence of higher concentration of NaCl were determined with reference to the basic mechanism for NaCl radiosensitization. As the results, inhibitions of DNA repair, of DNA degradation, of macromolecular syntheses and of RNA species formation were found in DNA repair proficient strains. The number of radiation-induced DNA-strand breaks was not increased by the presence of 1M NaCl during irradiation. It was suggested that inhibition of DNA repair may be of primary importance among these lesions for NaCl radiosensitization.

View full abstract

Six pairs of enantiomeric N-(purin-6-yl) amino acid methyl esters were synthesized and tested for their cytokinin activities by three bioassay systems, the growth of tobacco callus, the seed germination of lettuce and the fresh weight increase of excised radish cotyledons. L-(-)-Antipodes were as a whole more active than the corresponding D-(+)-isomers in the tobacco callus and seed germination tests, whereas an uniform tendency was not observed in the radish cotyledon expansion. The discussions were focused on the effects on the biological response of configurational arrangements around the asymmetric center at α-position to the adenine ring and on species difference of cytokinin receptor molecules.

View full abstract

Racemic citronellol was converted to a Stereoisomeric mixture of 3, 7-dimethylpentadec-2-yl acetate, the sex pheromone of the pine sawflies.

View full abstract

Intracellular DNA breaking activities of aromatic reductones derived from adrenalone were compared by use of the neutral sucrose gradient centrifugation. The activity of adrenalone derivatives was also tested in the presence of Cu²⁺ on λ DNA. The compounds which was highly active on the breakage of intracellular DNA were not necessarily the potential breaker of λ DNA. HeLa cells were more resistant than RFL cells against the splitting action of aromatic reductone derivatives on intracellular DNA, indicating that cellular sus-ceptibilities to the breaking action of the derivatives were different depending upon cell lines. 3, 4-Dihydroxyphenylglyoxime was the most powerful drug to break chromatin DNAs in both HeLa and RFL cells. A part of double strand breaks of the cellular DNA provoked by the drug was repaired, however some were still not repaired in spite of post-cultivation of the cells over many generations.
The partial repair seemed to be indispensable to cellular post-proliferation.

View full abstract

The structure of sulfated oligosaccharide II, one of the main sulfated oligosaccharide chains of ovomucin, has been determined. This oligosaccharide was found to compose of each 1 mole of N-acetylgalactosaminitol, galactose, N-acetylneuraminic acid and sulfate. The sequential periodate oxidation, borohydride reduction and acid hydrolysis of N-acetylneuraminic acid-free oligosaccharide resulted in the formation of glycerol and N-acetylthreosaminitol.
From these results, the following structure was proposed for sulfated oligosaccharide II: N-acetylneuraminyl-(2→3)-galactosyl-(1→3)-N-acetylgalactosaminitol-6-sulfate.

View full abstract

Whole casein dephosphorylated almost completely with a bovine spleen phosphoprotein phosphatase was prepared and its coagulation by chymosin and its proteolysis by chymosin and other proteases were compared with those of native whole casein. Dephosphorylated casein coagulated more slowly than native casein in the calcium caseinate system containing 20mM calcium. The yield of coagulated protein was the same for both caseins. Calcium content of the precipitate from dephosphorylated casein was less than one fourth of that from native casein. Dephosphorylated casein gave a much softer gel than native casein when com-pared in the sol system prepared by Grindrod et al. General proteolysis of casein with chymo-sin at pH 6.8 and with pepsin at pH 1.8 was accelerated and that with trypsin at pH 8.2 was retarded by dephosphorylation of casein.

View full abstract

From the phytopathogenic fungus, Colletotrichum nicotianae, three phytotoxic substances have been isolated and named colletotrichin, colletotrichins B and C (1, 2 and 3). The struc-tures of these compounds have been elucidated from the physical and chemical evidence. When applied on the tobacco leaves, colletotrichins induced the symptom similar to that of the tobacco anthracnose caused by C. nicotianae. The compounds were also toxic to the lettuce and rice seedlings.

View full abstract

An α-1, 3-glucanase was purified to homogeneous state from culture broth of Clado-sporium resinae. The enzyme was purified through salting-out with ammonium sulfate, followed by column chromatographies on DEAE^*3-Sephadex, hydroxyapatite, and Sephadex G-100. A pepsin inhibitor from Streptomyces was added on each step of purification to prevent pro-teolytic cleavage of the α-1, 3-glucanase protein by contaminating enzymes. The purified enzyme showed no action on CMC^*3, β-1, 3-glucan, dextran, starch, pullulan or maltose. The enzyme was most active at pH 4.5 and 47°C, stable at 4°C at pH 3.5_??_7.0, and not in-activated up to 47°C on heat-treatment for 30 min at pH 4.5. Its molecular weight was estimated to be 87, 000 and 88, 000 by SDS^*3-polyacrylamide gel electrophoresis and gel filtra-tion, respectively, and the isoelectric point to be 3.2. The Michaelis constant for α-1, 3-glucan was 13mM (as anhydroglucose units). The α-1, 3-glucanase was found to liberate α-glucose successively from the non-reducing ends of α-1, 3-glucans. It acted on pseudonigeran, α-1, 3-glucans from Lentinus edodes and Polyporus betulinus, as well as insoluble glucans produced by Streptococcus mutans and Streptococcus salivarius. Oligosaccharides of the nigerose series with the degree of polymerization above 4 were rapidly hydrolyzed by the enzyme, and nigerose was also attacked at high enzyme concentrations.

View full abstract