The degree of gelatinization of potato starch was measured by the apparent optical density of starch-water suspensions at 530nm during isothermal gelatinization at 52.5-72.0°C. From the temperature dependence of the gelatinization rate, the activation energy of gelatinization was determined to be 22±6 kcal/mol, being in good agreement with the value obtained by the enzymic digestion method in the previous paper. The gelatinization temperature as measured from the halftransition was found to be 61.1°C which is slightly higher than the value of 59.1°C determined by the glucoamylase method. Fromthe transition curve, the van't Hoff enthalpy was evaluated to be 117±3 kcal/mol.

View full abstract

The gelatinization of potato starch in water was studied by quantitative differential thermal analysis at various heating rates ranging from 0.02 to 20K min^-1. It was found that at a heating rate slower than 0.5K min^-1 the gelatinization state is at all times in equilibrium uring the temperature scan, while it is kinetically limited at a heating rate faster than 0.5 K min^-1. The heat of gelatinization was calorimetrically obtained as ΔH_cal =2.77 ±0. 15 kJ (glucose residue)^-1 (661 ± 36 cal (glucose residue)^-1) Using the transition curve drawn from the enthalpy level, the van't Hoff enthalpy for gelatinization was determined to be ΔH_vH=816±8kJ mol^-1 (195±2 kcal mol^-1). From the ratio of the van't Hoff enthalpy to the calorimetric enthalpy, the size of the cooperative unit during the gelatinization of potato starch was estimated to be 295 ± 10 (glucose residues) mor^-1).

View full abstract

Glucose oxidase (EC 1.1.3.4) was inactivated almost completely at pH 7.0 (0.1 M sodium phosphate buffer, ionic strength = 0.22) by the cationic detergent, hexadecyltrimethylammonium bromide at a molar ratio of HTAB/GOD ?? 1, 700. This inactivation was accompanied by 1) a blue shift in the region of 270-300nm, 2) an increase in FADfluorescence at 520nm, and 3) an approximately 3-fold increase in tryptophan fluorescence at 340 nm. The extent of inactivation of glucose oxidase by the cationic detergent was different from that observed with other detergents under the sameexperimental conditions. Whenthe substrate, D-glucose, was added to the enzyme solution before the addition of hexadecyltrimethylammoniumbromideunder anaerobic conditions, the activity of glucose oxidase decreased to 70% of its original value after incubation at 25°C for 24 hr. In contrast, an anionic detergent, sodium dodecylsulfate, or a nonionic detergent, Triton X- 100, did not produce measurable changes in the enzyme activity.
Thus, the inactivation of glucose oxidase by the cationic detergent is caused by the formation of an ion-pair between a cationic head group of the detergent and anionic amino acid residues of the enzyme.

View full abstract

A strain of Micromonospora sp. produced a new substance capable of inhibiting β-glucuronidase activity. The inhibitor, abbreviated as M-GCI, was purified by means of ethanol treatment, column chromatography on DEAE-cellulose, and gel filtration on Sephadex G-50 from the culture filtrate, and properties of the purified preparation have been investigated. M-GCI is a glycoprotein which has a molecular weight of about 8, 700. The protein constituents lack S-containing and basic amino acids. The inhibitory activity of M-GCI was sensitive to pH. It was stable in the alkaline pH range, but gradually lost its inhibitory activity as the acidity increased. M-GCI showed strong inhibition against β-glucuronidase from Escherichia coli and a-glucosidase from yeast. Since MGCI showed little effect on β-glucuronidase from bovine liver, the inhibitory action of M-GCI seemed to be rather specific for the β-glucuronidase from E. coli. These properties have proved that M-GCI is completely different from the other inhibitors of β-glucuronidase so far reported.

View full abstract

Three types of blocked mutants were isolated from Streptomyces griseus subsp. cryophilus, which produces ight 5, 6-cis carbapenem antibiotics and penicillin N. The type I mutant was defective in producing dimethylated compounds at the C-8 position (C-19393 H₂ and S₂). The type II mutant, derived from the type I mutant, could not produce compounds with a sulfoxidated side chain at the C-2 position (C-19393 E₅ and MM 4550 as well as C-19393 H₂ and S ₂). The type III mutant accumulated only epithienamycin A and MM 17880 in large amounts. On the other hand, 8-dimethylated compounds with a saturated or deoxidized side chain at the C-2 position could not be detected in culture filtrates of the parent or these mutants. Based on the results, we propose a possible biosynthetic pathway for 5, 6-cis carbapenem antibiotics.

View full abstract

All possible 1-methylpyrazole carboxanilides and their mono- and dimethyl derivatives have been synthesised and assessed for their effectiveness in inhibiting the mycelial growth of Rhizoctonia solani and for the control of root rot disease caused by that organism in cotton seedlings. The structural requirements for activity are discussed and compared with previous assessments of general structure-activity relationships in carboxamide fungicides.

View full abstract

A series of alkyl 3-alkylamino-2-cyanoacrylates was synthesized and assayed as inhibitors of the Hill reaction in isolated pea chloroplasts. The results suggest that there is a single centre in these molecules, possibly the carbonyl group, which specifically interacts with the inhibitor receptor site and that maximum activity is associated with an asymmetric distribution about this centre of lipophilic alkyl groups which are involved in non-specific binding to discrete hydrophobic regions.

View full abstract

A series of alkoxyalkyl-3-alkylamino-2-cyanoacrylates and related compounds have been synthesised and their Hill inhibitory activity determined in isolated pea chloroplasts. The results suggest that the alkyl group attached to the amino function interacts with a mobile lipid phase in the thylakoid membrane whilst the alkoxyalkyl group interacts with a smaller, more ordered, lipid environment. It is suggested that the former region corresponds to the interior of the lipid membrane and the latter to membrane or proteinalkyl chains in the vicinity of the membrane-protein interface. There is evidence of a localized hydrophilic pocket in the more constrained lipid environment.

View full abstract

Single- and double-strand breaks in deoxyribonucleic acid (DNA) of Deinococcus radiodurans R1 cells caused by heating at 55°C for 8 min were rejoined by post-heating incubation in nutrient borth. In the presence of novobiocin (30μg/ml) or phenethyl alcohol (0.5%), inhibitors of DNA synthesis, the repair of single-strand DNAbreaks was inhibited, and the restoration of growth and DNAsynthesis during post-heating incubation was also inhibited completely. A recombinationdeficient mutant strain (rec30) was more sensitive to heat than the wild type strain Rl. Whenboth the strains were heated at 55°C for 8 min, the survival fraction ofRl cells was nearly 100%, but that of rec30 cells was only approximately 0.01%. Though the breaks of DNAmolecules induced by heating at 55°C for 8 min occurred in both rec30 cells and Rl cells, the DNAbreaks in the former cells were not restored during post-heating incubation in nutrient broth. Therefore, it can be concluded here that post-replication repair i.e. recombination repair, contributes to the repair during post-heating incubation of heat-induced DNAinjury of D. radiodurans cells.

View full abstract

An arabinase has been purified from the culture fluid of Erwinia carotovora IAM 1024 grown on a mediumcontaining arabinan. The purified enzymewas active on beet arabinan and inactive on 1, 5-arabinan, arabinoxylan, arabinogalactan, and p-nitrophenyl α-L-arabinofuranoside. The optimumpH was 6.0. The enzyme was stable over a pH range of5.0 to 1 1.0. Whenthe purified enzyme acted on beet arabinan, the main product was arabinotriose.

View full abstract

Sesquiterpene dialdehydes, isolated originally as insect antifeedants from East African Warburgia trees, have been shown to exhibit strong antimicrobial activity. Their chemical reactivities and biological activities were investigated in comparison with those of related compounds. There was a good correlation between the antifungal activity and the papain inhibitory activity of these compounds. Both activities appear to result from their highly specific reactivity with sulfhydryl groups. Consideration of the structure-activity relationships led to the proposal of a structure unit, the enal-aldehyde moiety, that is essential to biological activity.

View full abstract

Physicochemical properties of the isozymes SP1 and SP2 of alginate lyase specific for poly-D-mannuronatewere investigated to elucidate their molecular sizes and shapes and conformational features. The molecular weight of each isozyme was about 25, 000 by ultracentrifugal analysis. This value was in good agreement with those from gel filtration experiments, and the sedimentation coefficients, s_{20, w}, were 3.0S for SP1 and 3.1S for SP2. The partial specific volumes, diffusion coefficients, frictional ratios and Stokes' radii were calculated by routine methods. These results suggested that the shape of the protein molecule of each isozymewasspherical. The circular dichroic spectra and optical rotatory dispersion showedthat the ordered structure of each isozyme molecule was most likely β-sheets. A more rigid conformation of SP2 than SP1 was observed by denaturation experiments and fluorescence properties.

View full abstract

Aromaconcentrates from twelve tea samples, manufactured by different withering processes from three varieties of tea leaves, were prepared and qualitatively and quantitatively analyzed by GC and GC-MS. The individual effects of (1) solar-withering, (2) indoor-withering with shaking and turn over treatment and (3) additional mass-rolling on the development of aroma components were illustrated by a comparison of the aroma compositions among12 tea samples.
The combined effect of these processes showed an increase in the concentrations of 23 main componentswith few exceptions. Remarkableconcentration increases of α-farnesene, nerolidol, jasmine lactone, benzyl cyanide and indole were recognized while that of linalool decreased.

View full abstract

Acid precipitated soybean protein (Soybean Protein Isolate, SPI) was phosphorylated with POCl₃ under an alkaline condition. The amount of incorporated phosphorus was 14μg per mgof SPI. Whenthe molecular weight of the SPI was taken as 360, 000 daltons, the mol ratio of phosphorus to protein was about 140. Aminoacid analysis for the phosphorylated SPI suggested that the type of phosphate bound to the protein was ortho-phosphoric acid, and that the phosphorylated amino acid residues were lysine and histidine. The association of phosphate to SPI was stable for more than 2 weeks at pH>5.0. The functions ofphosphorylated SPI were examined at various pH levels. The high solubility of phosphorylated SPI at pH>3.0 did not decrease the emulsifying ability and gel forming ability, even in the acidic range when compared with the neutral range, whereas the SPI lost most solubility and functionality at pH<5.5. There was no difference between the digestibility of phosphorylated SPI and SPI. These results suggested that phosphorylated SPI is a very useful food material possessing good functional properties throughout a wide pH range.

View full abstract

Six monohydroperoxides of methyl arachidonate were fractionated, and each isomer was incubated so as to be decomposed (further oxygenation). The products were analyzed by GC-MS after derivatization. DiOH, triOH, tetraOH and pentaOH compounds were obtained, and their formation mechanismsare discussed.

View full abstract

Odorous compounds in heated swine feces were isolated by means of vacuum distillation under frozen state in o der to identify the odorous substances evolved from a hot-air drier of swine feces. Identification and quantification of odorous components were carried out by gas chromatographymass spectrometry and gas chromatography, respectively. Raw swine feces were also analyzed as a control. The most important compounds for malodor were various kinds of alkylpyrazines which were newly produced during heating. Large decreases of fatty acids and indoles and increases of alcohols were observed in heated feces. Quantities ofphenols and methyl ketones were not changed significantly by heating.

View full abstract

The structure of a new sesquiterpene antibiotic, terrecyclol (I), from Aspergillus terreus Thorn No. 14 was determined to be I. The antimicrobial activity ofI is as high as that ofterrecyclic acid A (II), which is a main antimicrobial product of Asp. terreus No. 14.

View full abstract

Thermomonospora curvata IFO 12384 was selected from many thermophiles tested as a strain capable of converting 2, 6, 6-trimethyl-2-cyclohexene- 1, 4-dione (4-oxoisophorone) into (6R)-2, 2, 6- trimethyl-1, 4-cyclohexanedione ((3R)-dihydro-4-oxoisophorone) efficiently. The other conversion products were also isolated and identified by spectrometry. Based on the results of experiments with a degradation sequence, a conversion pathway for 4-oxoisophorone by this thermophile is proposed. The effects of nutritional conditions, temperature, initial pH and the concentration of the substrate on the conversion were examined. Under the optimal conditions, the conversion ratio of 4-oxoisophorone to (3R)-dihydro-4-oxoisophorone was over 95%. The production rate of (3R)- dihydro-4-oxoisophorone was 86mg per 1 g of dry cells per hr.

View full abstract

Saccharomyces diastaticus produces extracellular glucoamylases and ferments starch. Wehave isolated glucoamylase-non-producing (amy) mutants from wild-type strains of S. diastaticus carrying a STAl gene after mutagenesis with ethylmethane sulfonate. All amy mutations were recessive and were divided into two complementation groups, amy1 and amy2. The amy1 group may be located in the STAl gene. The amy2 mutation was involved in both glucoamylase production and flocculation.

View full abstract

Saccharomyces cerevisiae is closely allied to Saccharomyces diastaticus which produces extracellular glucoamylases and ferments starch. Tetrad analysis using S. cerevisiae, S. diastaticus and their recombinant progenies revealed that S. cerevisiae carries two negative genes against glucoamylase production: one was designated sta° and the other, INH1.

View full abstract

Resting cells of ribulose monophosphate pathway (RMP)-type methylotroph strain OM33and serine pathway-type methylotroph Pseudomonas FM518actively catalyzed the formation of lmethionine from DL-homocysteineand methanol. Cyanocobalaminstimulated the L-methionine formation by strain OM33, indicating that vitamin B₁₂ dependent homocysteine transmethylase functions in this obligate methylotroph. Whereas, the L-methionine formation by Pseudomonas FM518was not stimulated by added cyanocobalamin because this strain is a vitamin B₁₂-producer. The Pseudomonas FM518 cells formed L-methionine with betaine or L-serine as well as methanol as the methyl donor source. The conditions for the formation of L-methionine from DL-homocysteine and methanol were investigated preliminarily using the reaction system with resting cells of an ethionine-resistant mutant of Pseudomonas FM518. The methanol-grown cells at the exponential phase of growth possessed the highest activity. Under the optimum reaction conditions, 2.6 mMlmethionine was formed from 30 mMDL-homocysteine and 0.8 m methanol.

View full abstract

Anewenzymatic acyloin-type condensation betweenpyruvate (or acetoin or methylacetoin) and D-glyceraldehyde was found to be catalyzed by cell-free extracts of a transketolase mutant of Bacillus pumilus IFO 12089. The reaction product (1) was isolated and determined to be 1-deoxy-D- threo-pentulose (d-DTP), which is considered to be a precursor of the five-carbon unit of the thiazole ring thiamine. l-Deoxy-L-threo-pentulose (l-DTP, 2) was synthesized similarly when lglyceraldehyde was used instead of D-glyceraldehyde. The configurations of 1 and 2 were confirmed by reduction to the corresponding 1-deoxy-pentitols.
Similar enzyme activities were also detected in cell-free extracts of all the wild-type strains tested of bacteria, actinomycetes, yeasts, and molds. These results suggest that the d-DTP synthesizing enzyme plays an important role in the biosynthesis of the thiazole ring of thiamine in vivo.

View full abstract

Two sesquiterpenoids, called components A₁ and A₂, were isolated from sweet potato root tissue either infected by Ceratocystis fimbriata or injured by HgCl₂, and their chemical structures were determined. Both components inhibited germination and term-tube growth of Ceratocystis fimbriata-oak strain. The above results indicate that the components are among the phytoalexins of sweet potato. When ¹⁴C-component A₂ was supplied to diseased tissue discs, the label was efficiently incorporated into dehydroipomeamarone, ipomeamarone, ipomeamaronol, and component B₁, indicating it to be a close precursor of these components. In the case of ¹⁴C-component A₁ administration, the label was mainly incorporated into the two unknown fractions.

View full abstract

An oxygen-resistant hydrogen bacterium developed during an autotrophic plate culture under 40%O₂. Whenoxygen-sensitive strain N34 was incubated under an atmosphere of 50%H₂ +40% O₂+10% CO₂, small white colonies (SW) first formed, and then, large yellow colonies (LY) developed from some of the SW. The LYcounts increased gradually. The hydrogenase activity of SWwas one-fifth that of LY. The growth lag period of a liquid culture under 40% O₂ inoculated with SWwas more than 100 hr, while it was almost zero with LY, indicating that SWwere oxygensensitive and LYoxygen-resistant. Whena single SWwas transferred to a fresh plate culture under 40% O₂ at first SWand then LY were formed again. On the other hand, LYwere always formed under 40%O₂ when a single LYwas transferred. From these data, it was concluded that SWwere formed from oxygen-sensitive strain N34 whose growth was inhibited under 40%O₂ and that oxygen-resistant LYwere formed as a result of adaptation of SWto high oxygen tension.

View full abstract

Two dye-linked alcohol dehydrogenases (EC 1.1.99.8) were purified from extracts of Rhodopseudomonas acidophila 10050 grown anaerobically on methanol and extracts of R. acidophila M402grown aerobically on vanillyl alcohol. Both dehydrogenases have the same name based on the rules of enzyme nomenclature, and have similar properties in coupling to phenazine methosulfate and requiring ammonia as an activator, but differences between the two enzymes could be pointed out in many aspects, especially as to their substrate specificities. The former enzymeis active on methanol, whereas the latter is enzyme is completely inert on methanol. While the former enzyme does not act on vanillyl alcohol, the latter enzyme shows high affinity for vanillyl alcohol and some aromati alcohols. Another evident difference is the behavior of the former enzyme toward oxygen. The methanol-induced enzymewas sensitive to oxygen. The enzyme lost its activity on exposure to oxygen, but the activity could be recovered by passing nitrogen gas over it for a few minutes. Therefore, these inactivation and reactivation changes of the enzymewere reversible. This implied a change of affinity constants for substrate alcohols on nitrogen treatment. Apparent Km values for methanol, ethanol, n-propanol and n-butanol were lowered to one-tenth the original values with nitrogen gas treatment, while maximumreaction velocities on these alcohols remained unchanged after nitrogen treatment.
We propose that the methanol-induced enzyme should be called an anoxygenic dye-linked alcohol dehydrogenase or dye-linked aliphatic alcohol dehydrogenase. The latter enzyme which is induced by vanillyl alcohol is better named a dye-linked alcohol (non-specific) dehydrogenase.

View full abstract

L-Glutamate in soy sauce was determined with L-glutamate oxidase partially purified from the aqueous extract of a wheat bran culture of Streptomyces sp. X-l 19-6. L-Glutamate was determined spectrophotometrically by measuring a-ketoglutarate or hydrogen peroxide with a good correlation coefficient with conventional autoanalyzer analysis with L-glutamate decarboxylase. The value obtained by hydrogen peroxide method indicated 85% of that of conventional method. L-Glutamate was also determined electrically by monitoring oxygen consumption of the enzymereaction mixture. This method is very simple and rapid but spend a large amount of enzyme.

View full abstract

A 2-alkenal reductase, which catalyzes the reduction of sorbaldehyde (trans-2, trans-4- hexadienal) to trans-4-hexenal, was purified from Mucor griseo-cyanus by dialysis against an acidic buffer solution (pH 5.2), salting-out fractionation with ammoniumsulfate, chromatography on DEAE-Sephadex, preparative disc electrophoresis, and gel filtration on Bio-Gel P-75. A 2-alkenal reductase of a microorganismwas purified for the first time. The molecular weight was estimated to be 2.6 x 10⁴ by SDS-disc electrophoresis, and the optimum pH was found to be 6.5. The enzyme was dependent on both NADPHand NADH, and was specific for cis-2-heptenal and -octenal in a series of 2-alkenals, trans-2-alkenals (C₄, C₆-C₁₀ and C₁₂), cis-2-alkenals (C₇ and C₈), acrolein, and trans-2-cinnamaldehyde.

View full abstract

Theoccurrence of bacteriocinogeny wassystematically investigated in 80 strains of aminoacid or nucleic acid producing bacteria and related species by cross-testing all the strains against each other. Spot test was also performed on ultraviolet light or mitomycinC treated culture broths of all strains. Consequently, it was found that 6 strains were bacteriocinogenic and 2 strains were lysogenic. Furthermore, 12 strains were induced to bacterial lysis by ultraviolet light or mitomycin C treatment and 10 of them produced phage-like particles following lysis. The bacteriocins, named linecin, maricin, mediolacin, and rosecin, were produced by Brevibacterium linens, B. maris, Corynebacterium mediolanum, and Micrococcus roseus, respectively.

View full abstract

The hydrogen bonding of C-H…X^- type of substituted alkanes in an aprotic solvent has been mainly studied with simple halogenated compounds, ¹⁾ and some glycosyl halides and aryl glycosides.²⁾ Recently, we have investigated the association of BHC³⁾and DDT⁴⁾ analogues with tetraalkylammonium halides, using ¹H-NMRspectroscopy, and found that specific hydrogens in the molecule such as three syn-axia¥ or three closely located hydrogen form a multiple hydrogen bond; the association constants of β- and δ-BHCwere much larger in their magnitude than that of the single hydrogen bond of chloroform, for example. In view of the possible correlation of such intermolecular association of BHCisomers with their translocation velocity in cockroach, ^{5, 6)} and recent advances in the mode of action of halogenated anesthetics, ⁷⁾ further studies on the effect of configuration and electronegativity of substituents on the multiple hydrogen bond were desired. This paper reports the association of myo- and epi-inositol hexatrifluoroacetates with tetrabutylammonium bromide in acetonitrile.

View full abstract