The reduction of 2, 6-dichlorophenolindophenol (DCIP) by 6-substituted 3-hydroxy-4-pyrones was studied in the pHrange of 3.0 to 7.8, using a stopped-flow apparatus.
1) Kinetic characteristics of 6-substituted 3-hydroxy-4-pyronesare shownas the apparent firstorder rate constant, k_app, or the second-order rate constant, k. The plot of log k against pHwas different from those obtained for the reactions of L-ascorbic acid and triose reductone with DCIP.
2) The log (k/k_H) of 6-substituted 3-hydroxy-4-pyrone solutions at acidic pHs have been correlated with Δδ_c-3 values for 3-hydroxy-4-pyrone.

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The alkalophilic Bacillus DNA bank, cloned in the expression probe plasmid pGR71, has been screened for the p esence of genetic elements regulated by temperature, pH or NaCl concentration. It was found that several kinds of regulatory elements were obtained whose expression was controlled by temperature, pH or NaCl concentration. Temperature effect was analyzed further. In B. subtilis the 1000 base pair HindIII fragment (pGR71-11-73) of alkalophilic Bacillus sp. was shown to decrease CAT activity at higher temperatures. However, CAT activity of B. subtilis carrying the plasmid pGR71-13-36 (1.3 kb HindIII fragment) was not changed by temperature.

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Plasmid PUO1, which is present in a fluoroacetate-assimilating strain of Moraxella sp., specifies two kinds of haloacetate dehalogenases, H-1 and H-2, and mercury resistance. The H-1 and H-2 genes were cloned onto plasmid pBR322 in Escherichia coli. The analysis of the cloned DNA fragments revealed the loci of both genes on the pUO1 map and also the direction of transcription. Two different hybrid pBR322s containing the H-1 gene were maintained stably in E. coli, while three hybrids containing the H-2 gene were so unstable that they readily disappeared or changed into various deletion mutants. It was suggested that the instability of the H-2 hybrid plasmids might be caused by a certain DNA structure adjacent to the H-2 gene which might be concerned in the deletion of the H-2 gene from pUO1.

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Gelatin, soy protein, lysozyme, succinyl-casein and succinyl-egg albumin were allowed to react with methyl linoleate (ML) at a relative humidity (RH) of 0% at 50°C for 7 days (protein : ML=1:1). Gel filtration indicated that only gelatin was extensively fragmented. The gelatin was then incubated with ML under various conditions, and changes in the molecular sizes, the gel forming abilities and the chemical characteristics were investigated. The fragmentation of gelatin was increased by decreasing the RH and with the increase in the ratio of ML to protein. The melting point of gel in heating and cooling gelatin was decreased by increasing the fragmentation. The contents of amide and carbonyl groups increased and that of amino group decreased as the reaction progressed at RH 0%, but no change in C-terminal amino acids was observed. Following the reaction at RH 0%, many kinds of amino acid residues of gelatin were damaged, although in our previous paper[Matoba et al., Agric. Biol. Chem., 46, 979 (1982)] such was not detected in casein and egg albumin. From the above results, we conclude that gelatin is susceptible to fragmentation by reaction with oxidizing lipids and one possible mechanism of the degradationmay be the-N-C-scission ofpeptide bonds as proposed by Zirlin and Karel [J. Food Sci., 34, 160(1969)]. Complex reactions other than this scission may also occur.

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To clarify the function of carboxyl proteinase inhibitor (S-PI, Pepstatin Ac) in the fruit-body formation of Basidiomycetes, we purified the carboxyl proteinase in the extract from Lentinus edodes fruit-bodies. About 70mg of purified enzyme was obtained from 6kg of wet fruit-bodies, with 20% recovery. The enzyme showed a single protein band on polyacrylamide gel electrophoresis.
The molecular weight and isoelectric point were 42, 000 and pH 4.5, respectively. The enzyme contained no arginine, and the contents of lysine and histidine residues were higher than those of other carboxyl proteinases in vegetative mycelium or culture filtrates. The enzyme was most active between pH 2.5-2.8, and stable over a range of pH 3.1-5.7 when incubated at 37°C, for 3 hr. The enzyme was inhibited by S-PI, DAN, and EPNP, which are specific inhibitors for carboxyl proteinases. The rate of inhibition by S-PI was very different from that in other carboxyl proteinases described above. The enzyme preferentially split the Leu(15)-Tyr(16) bond of oxidized insulin B-chain at the rate of 70% for total hydrolysis. These characteristics are compared with those of other carboxyl proteinases.

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The process to a thermal equilibrium state of nonglutinous and glutinous rice starch-water mixtures around the gelatinization temperature (40-85°C) was studied by differential scanning calorimetry (DSC). The starch-water mixture was held at a constant temperature for an appropriate duration between 5 min and 140 hr, and then the usual DSC was carried out. Since the low temperature side of the peak of the DSC curve after the holding shifted to a higher temperature as the holding time proceeded, the peak gradually narrowed and grew higher. Even after a 100-hr holding, the DSC spectrum continued to change, indicating that an equilibrium state had not yet become established, so far as the constant holding temperature was concerned. By contrast, the gelatinization enthalpy reached a constant value corresponding to a holding temperature of less than 5min. In the course of holding, the crystalline structure of the X-ray diffraction pattern decreased. Only an amorphous component was observable in the pattern after holding for 22 hr at 75°C, corresponding to a state which showed a sharp endothermic peak in the DSC curve after holding for that time.

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A new enzyme system which produces gentiobiose from curdlan (β1, 3-glucan) was discovered in the culture filtrate of Streptomyces, and a preparation method for gentiobiose using the enzyme system was investigated.
The optimum pH and temperature of the enzyme system for curdlan-decomposing activity were 5.0 and 55°C, respectively.The enzyme system was stable at pH 3.0 to 7.0 on 1 hr incubation at 37°C.The treatment at 60°C for 3hr showed a complete loss of the activity.
On the other hand, a suitable pH for gentiobiose formation from curdlan was 6.0.When curdlan was hydrolyzed by the enzyme system under optimum conditions for the formation of gentiobiose (pH 6.0 and 50°C), the resultant hydrolyzate was composed mainly of glucose and gentiobiose in an approximate ratio of 4:1 by weight.Moreover, the yield of gentiobiose based on curdlan increased when the enzyme reaction was initiated with the addition of glucose to the reaction mixture.By the application of the enzyme system, the hydrolyzate containing 18.5 g of gentiobiose was obtained from 50 g (42.3 g as anhydroglucose) of curdlan and 100 g of glucose, and 14.7 g of crystalline gentiobiose was obtained after separation by carbon column chromatography.

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Conditions for tryptophan synthesis from pyruvic acid, indole and NH₄Cl by Enterobacter aerogenes AHU 1540 having a high tryptophanase activity, were investigated using a reaction mixture containing 1.7% ofpyruvic acid. Under optimum conditions, 16.4 g/liter oftryptophan was accumulated after 24 hr of incubation.
Agaricus campestris AHU 9382 produced pyruvic acid in amounts of 22 - 26.5 g/liter from 5% of glucose after 3-days shaking culture. When E. aerogenes was added to this fermentation broth together with indole and NH₄Cl, pyruvic acid produced was rapidly converted to tryptophan and yields of tryptophan as high as 15 g/liter were obtained after 12hr of incubation. Furthermore, pyruvic acid fermentation by Saccharomyces exiguus AHU 3110 or Corynebacterium sp. 37-3A could also be used as a pyruvic acid source for subsequent tryptophan production.

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To elucidate the effect of nutrition during induction on peripheral muscle responsiveness to insulin, the incorporation of radiolabeled glucose to glycogen and the uptake of radiolabeled deoxyglucose were studied in isolated diaphragms from the fetuses of normal and diabetic pregnant rats in vitro. Basal- and insulin-stimulated incorporation of [1-¹⁴C]glucose into diaphragm glycogen were greater in the fetuses of diabetic mothers (IDM) than in normal fetuses, but there was no difference in the degree of stimulation by insulin of labeled glucose into glycogen between normal fetuses and IDM. Diaphragms from normal fetuses and IDM had the same basal up ake of 2-deoxy-[1-³H]glucose as well as insulin-stimulated uptake. Consequently the sensitivity of glucose uptake to insulin was similar both in normal fetuses and IDM. These data indicate that glucose utilization (incorporation of labeled glucose into glycogen) was increased in IDM, but that the response of glucose uptake and glycogenesis to insulin was not altered.

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The effect of combining a cyclopropyl group with a benzo- 1, 3-dioxole group on their synergistic property has been studied by synthesizing a large number of such compounds.The factor of synergism, R_m values and spectroscopic data of these compounds is reported.

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Enzymatically modified proteins produced from gelatin by papain-catalyzed incorporation of leucine hexyl ester and leucine dodecyl ester, designated as EMG-6 and EMG-12, respectively, were investigated for their surface properties. Both EMG-6 and EMG-12 had critical micelle concentrations of 0.1-0.2% and 0.02-0.04%, respectively, reducing the surface tension of water as rapidly as synthetic surfactants, while bovine serum albumin, casein and gelatin hydrolysate used as controls induced much slower rates of reduction in the surface tension. Application of the Gibbs adsorption equation gave area requirements of 77A² molecule and 48A² molecule for EMG-6 and EMG-12, respectively. Functional properties such as emulsifying activity index, emulsion viscosity, emulsion stability, whippability and foam stability were evaluated, with the results that these parameters for EMG-6 and EMG-12 were not greatly influenced by pH of the aqueous medium studied.

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Enzymatically modified proteins produced from gelatin by papain-catalyzed incorporation of leucine hexyl ester and leucine dodecyl ester, designated as EMG-6 and EMG-12, respectively, are known to be potent surfactants [Agric. Biol. Chem., 46, 173 (1982)]. In the present study, experiments were carried out to characterize the phase behavior of these surface-active proteins in concentrated aqueous systems at elevated temperatures. For 60%- and 70%-EMG products, it was found that their elasticity and viscosity as represented by the storage modulus (G') and loss modulus (G"), respectively, decreased greatly at 30°C and 80°C. Polarized microscopic observations showed that in the temperature range of 30-80°C, a liquid crystalline structure of a lamel ar type was formed. Differential thermal analysis demonstrated that, in accordance with the liquid crystal formation, an endothermic process took place, which gives evidence for an energetic change associated with this phase transition. Such phase transition phenomena were not observed for a gelatin hydrolysate, bovine serum albumin and casein used as controls.

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Two new photoactivable heterobifunctional reagents, 1-azido-5-naphthalene sulfonyl chloride (ANS-C1) and the N-hydroxysuccinimide ester of 1 -azido-5-naphthalene sulfonyl aminopropionate (NHS-ANS-AP), were synthesized and characterized. The reagents were applicable to the groupdirected modification of ligands. Upon exposure to ultraviolet light, the non-fluorescent modified ligands generated reactive nitrene intermediates which could react with neighboring molecules to form fluorescent products. This was demonstrated by the covalent modification of bovine serum albumin with ANS-AP by photolysis. NHS-ANS-AP was used for the preparation of a photoreactive invertebrate lectin.

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The structures of alkyl radicals generated in several methyl esters of fatty acids by irradiation with UV light were studied by the spin trapping technique. A spin trap, deuterated nitrosodurene, traps alkyl radicals in both saturated and unsaturated esters at the ambient temperature. The trapped radicals and their hyperfine splitting constants from several esters were as follows: pentadienyl radicals (a_N=13.8-14.0G, a_H=5.9-6.0G) from methyl linoleate, linolenate and docosahexaenoate; allyl radicals (a_N=13.9G, a_H=6.8 G) and α-carbon radicals (a_N=13.3G, a_H=10.0G) from methyl oleate and elaidate;α-carbon radicals (a_N=13.3-13.4G, a_H=9.6-10.0G) and secondary alkyl radicals (a_N=13.9G, a_H=6.8-7.2G) from saturated esters.

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Two new components of botrytised wine were identified: 4, 5-dimethyl-3-hydroxy-2(5H)-furanone (Sotolon) and et yl 9-hydroxynonanoate. Sotolon, the key substance of cane sugar aroma, was identified as the sugary flavor substance of botrytised wine by means of gas chromatography-mass spectrometry after column chromatographic separation on DEAESephadex and silica gel. Ethyl 9-hydroxynonanoate was identified by chemical ionization and electron impact mass spectrometry. To evaluate the role of 17 volatile and 5 nonvolatile compounds characteristic of botrytised wine, these compounds were added to a normal wine. This produced a sweet, honey-like flavor similar to that of botrytised wine. The importance of Sotolon and the role of each group of flavor substances in producting this flavor was clarified by omission tests.

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Nondialyzable melanoidins prepared from a glucose-glycine system were incubated with glucose oxidase under optimal conditions and then the melanoidins were decolorized to 65%. The decolorization of melanoidins by glucose oxidase may be mainly caused by hydrogen peroxide produced from the enzyme-substrate reaction. Therefore, oxidative decomposition and decolorization of melanoidins were tried using hydrogen peroxide. Melanoidins were treated with hydrogen peroxide (final cone. 6.72%) under neutral (pH 7.0) and alkaline (pH 10.0) conditions at 37°C for 28hr. Melanoidins were decolorized to 64% and 97%, respectively the under above optimum conditions. The mean molecular weight of melanoidins decreased from 5, 300 to 3, 500 after hydrogen peroxide treatment. The major components in the ether-soluble fraction obtained from melanoidins by oxidative degradation of alkaline hydrogen peroxide were identified as 2- methyl-2, 4-pentanediol, Af, 7V-dimethylacetamide, phenol, acetic acid, oxalic acid, methylpropanedioic acid, propanedioic acid, 2-furancarboxylic acid, butanedioic acid, 2-hydroxypropanoic acid, 2, 5-furandicarboxylic aicd and 5-(hydroxymethyl)-2-furancarboxylic acid. On the other hand, the major degradation product in aqueous fraction was identified as glycine, and glycine was produced in 1.73% yield per nondialyzable melanoidin.

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A method for analyzing the headspace volatiles of tobacco with an ether trap has been developed and the headspace volatiles of four kinds of tobacco, flue-cured, Burley, domestic (cv. Matsukawa) and Turkish, were analyzed. Dried air was passed through cut tobacco and the headspace volatiles swept were absorbed in ice-cooled ether. The ether solution of headspacevolatiles was analyzed, and 27 components were identified by GC and GC-MS. Of these 27 components, six have not previously been reported as components in the tobacco headspace volatiles. The individual headspace volatiles samples of the four kinds of tobacco each showed their characteristic GC profiles and odors. The odor and the GC profile of each headspace volatiles sample were different from those of the steam distillate of the same tobacco.

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Endogenous gibberellins (GAs) in immature seeds and flowering ears of rice (Oryza sativa L.) were investigated, and six 13-OH GAs (GA₁, GA₁₉, GA₂₀, GA₂₉, GAMand GA₅₃) and five 13-H GAs (GA₄, GA₉, GA₂₄, GA₃₄ and GA₅₁) were identified. The existence of these GAs suggests that two major GAbiosynthetic pathways exist in rice, one being that of the 13-OHGAseries and the other, the 13-H GAseries. The major GAwas GA₄in ears, and GA₃₄in immature seeds. The occurrence of 13-H GAsin reproductive organs suggests that 13-H GAsmayplay important roles in the regulation of reproductive growth.

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Themetabolic fates of the carbonskeletons of L-(U-¹⁴C)arginine, proline and glutamic acid were investigated in growing rats fed with diets containing different percentages of protein calories (0, 5, 10, 15 and 30 PC%) at 4100 kcal ofmetabolizable energy per kg of diet.
The incorporation of ¹⁴C into body protein at 12hr after the injection of ¹⁴C-arginine was more than 50% of the dose in all dietary groups, showing a high efficiency of utilization of this amino acid for protein synthesis. The incorporation of ¹⁴C into body protein from ¹⁴C-proline was most increased in the 15 PC%group, and the values were reduced in rats fed with lower and higher PC%diets. The carbon skeleton of ¹⁴C-glutamic acid was extensively oxidized to expired carbon dioxide, and the ¹⁴C incorporation into body protein was markedly less. The pattern of expired ¹⁴CO₂production from each ¹⁴C-amino acid was in inverse proportion to that of ¹⁴C incorporation into body protein. The results indicate that the metabolic responses of arginine, proline and glutamic acid to dietary protein change at 10 to 15 PC%, where the growth rate reached its approximatemaximum.

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Such (+)- and (-)-cw-cycloheximide isomers as isocycloheximide (la, lb), a-epiisocycloheximide (2a, 2b) and neocycloheximide (3a, 3b) were synthesized by aldol condensation of (-)-(2R, 4R)- and (+)-(2S, 4S)-cis-2, 4-dimethyl-l-cyclohexanone (5a, 5b), obtained by microbial resolution, with 4-(2-oxoethyl)-2, 6-piperidinedione (7). The absolute configuration of the ( - )-cisketone 5a was confirmed by chemical correlation with natural (2S, 4S, 6S, αR-cycloheximide (4). The newly synthesized isomer, (-)-α-epiisocycloheximide (2b), showed strong antimicrobial activity against S. cerevisiae and P. oryzae close to that of natural cycloheximide (4).

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To ascertain whether the phosphorylation-dephosphorylation reaction is actually involved in the in vivo regulation of intestinal 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase, dietary modulation of the activation state of the enzyme was studied in isolated epithelial cells of rats. Substitution of a sucrose-enriched semipurified diet for the commercial non-purified diet caused a significant increase in jejunal activity with a concomitant decrease in ileal activity. Jejunal activity increased without influencing the activation state whereas at the early stage of dietary manipulation, there was a rapid decrease in apparent activity compared to total activity in the ileum, hence the reduction of the activation state. These observations favor the view that the phosphorylation (inactivtion) reaction is responsible for the regulation of intestinal HMG-CoA reductase in vivo. In contrast, dietary fat-dependent stimulation of jejunal reductase activity was mainly attributable to an increase in enzyme protein rather than in the level of the activation. The results suggest a complex controlling feature of the cholesterol synthesis in the intestine.

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Quinoxaline and benzimidazole derivatives obtained from L-rhamnose and L-fucose under deoxygenated, weakly acidic, heated conditions were studied using GLC, HPLC, and NMR.
Four quinoxalines and one benzimidazole were obtained from L-rhamnose (RHA-I, II, III, III', and IV) and L-fucose (FUA-I, II, III, IV, and V) in an acidic solution (MeOH-AcOH-H₂O= 8:1:2) at 80°C. The total yield of the products as sugar was about 80%from either rhamnose or fucose.
The structure of RHA-I was (2'S')-2-methyl-3-(2'-hydroxypropyl) quinoxaline; RHA-II, (2'R, 3'S)-2-(2', 3'-dihydroxybutyl) quinoxaline; RHA-III, (1'S, 2'S, 3'5)-2-(1', 2', 3'-trihydroxybutyl) quinoxaline [2-(L-arabino-1', 2', 3'-trihydroxybutyO) quinoxaline]; RHA-III ', 2-(L-ribo- trihydroxybutytl) quinoxaline; and RHA-IV, 2-(L-manno-1', 2', 3', 4'-tetrahydroxypentyl)- benzimidazole, and the structure of FUA-I was the same as RHA-I; FUA-II, (2'S, 3'S)-2-(2', 3'- dihydroxybutyl) quinoxaline; FUA-III, (1'R, 2'R, 3'S)-2-(1', 2', 3'-trihydroxybutyl)quinoxaline [2-(L-xylo-1', 2', 3'-trihydroxybutytyquinoxaline; FUA-IV, 2-(L-lyxo-1', 2', 3'-trihydroxybutyl)- quinoxaline; and FUA-V, 2-(L-galacto-1', , 2', 3', 4'-tetrahydroxypentyl) benzimidazole. These results suggest no significant difference for the pathways of quinoxaline and benzimidazole formation between L-rhamnose and L-fucose. Possible pathways are proposed for each sugar.

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Microbial protease inhibitors, bestatin and leupeptin, were per fused through hindquarters, and the effects of these inhibitors on the amino acid release and the accumulation of acid soluble peptides were studied using normal and Streptozotocin-induced diabetic rats. Both inhibitors depressed the amino acid release from the hindquarters of normal rats. However, leupeptin, unlikebestatin, failed to suppress the release of amino acids in diabetic rats. Bestatin caused an accumulation of acid soluble peptides in per fused skeletal muscle. However, leupeptin did not show this effect. The amino acid composition and the N-terminal amino acids were analyzed on the acid soluble peptides accumulated after bestatin per fusion. Branched-chain amino acids were preferentially accumulated as the acid soluble peptides, and more than half of the total amounts of these amino acids were located in the N-terminus. From these results, it was concluded that bestatin-sensitive protease(s), probably leucine aminopeptidase and/or arylamidase, play an important role in the degradation process of skeletal muscle proteins, especially in the steps to degrade acid soluble peptides into free amino acids.

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6-Isopentenylnaringenin 1, which has previously been synthesized by other workers, was isolated together with xanthohumol 2 and isoxanthohumol 3 from hard resins of hops (Humulus lupulus L.). The structures of 1 and sophoraflavanone B were examined; that of the latter previously reported as 6-isopentenylnaringenin, has been revised to 8-isopentenymaringenin. 1, 2 and 3 were found to have antifungal activities.

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Erwinia exopolygalacturonate lyase is strongly activated by Na⁺, but very weakly by divalent cations such as Ca²⁺, in contrast to most of the knownpectic lyases; nevertheless, this enzyme is completely inhibited by 1 mM EDTA. In this work, six polyamino carboxylates such as EDTA and a polyamine were examined for their effects on the enzyme activity.
EDTA, trans-1, 2-cyclohexanediaminetetraacetate, and diethylenetriaminepentaacetate inhibited the enzyme stron ly, but ethylenediaminediacetate showed little inhibition. Only triethylenetetramine stimulated the enzyme. The removal of EDTA from the enzyme solution resulted in an almost complete restoration of the activity. The EDTA-treated enzyme as well as the untreated one revealed no requirement for any divalent cations. The inactivation by hydroxyethylenediaminetriacetate, a mild inhibitor, was the mixed type. It seems most likely that the inactivation by the polyamino carboxylates is caused not by sequestering any metals but by directly forming an enzyme-chelator complex.

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The application of fast atom bombardment-and secondary ion-mass spectrometry to the Determination of molecular weights of non-volatile toxins was successfully examined with the use of authentic specimens of paralytic shellfish poisons (saxitoxin, gonyautoxin-1 gonyautoxin-2 and protogonyautoxin-1) and tetrodotoxin.
Two non-sulfated toxins, saxitoxin and tetrodotoxin, produced intense pseudomolecular ion peaks in both positive and/or negative ion detection. On the other hand, each of gonyautoxin-1 and -2 and protogonyautoxin-1, all sulfated, gave only small (M+H)⁺ ion peaks in the positive ion detection whereas exhibiting prominent (M-H)^- ion peaks in the negative ion spectrum.
The molecular weights thus determined were 299 for saxitoxin, 41 1 for gonyautoxin-1, 395 for gonyautoxin-2, 475 for protogonyautoxin-1 and 319 for tetrodotoxin, in good accordance with their molecular weights.

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Bovine κ-casein, a phosphoglycoprotein, has mucin-type carbohydrate chains. Subcellular distribution of enzymes that take part in the post-translational modification of κ-casein was examined. In lactating mammaryglands from rats and cows, .N-acetyl-galactosaminyl transferase, galactosyl transferase, sialyl transferase, and casein kinase were localized specifically in the Golgi apparatus.
The substrate specificities indicate that these enzymes are actually responsible for the processing of κ-casein.
The presence of a phosphate group attached to K>casein did not affect the rate of glycosylation by N-acetyl-galactosaminyl transferase, while the presence of carbohydrate chains attached to κ-casein strongly reduced the rate of phosphorylation by casein kinase. These results suggest that in the Golgi apparatus, phosphorylation of K-casein precedes glycosylation.

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L-Phenylalanine was converted to optically impure (R)-(+)-2, 6-dimethy1-1, 5-heptadien-3-ol 2 (19% e.e.). (R)-(+)-2 (96% e.e.) was prepared by a kinetic resolution of (±)-2. Acetylation of the pure (R)-( + )-2 gave the pheromone of the Comstock mealybug (Pseudococcus comstockii KUWANA) [(R)-( + )-1].

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Lipase from Aspergillus niger NRRL 337 catalyzed the synthesis of esters from various dicarboxylic acids and diols. Amongthe esters synthesized, those from 1, 13-tridecanedioic acid and 1, 3-propanediol were separated by gel permeation chromatography. The constitution of the purified ester was determined by using IR and MS. The dominant components of synthesized esters were pentamer and heptamer, and both end groups of the pentamer and heptamer were hydroxyl.
The possible reaction sequence in synthesis of ester oligomer by Aspergillus niger lipase is described.

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In the cell-free extracts and intact cells of an obligately autotrophic, extremely thermophilic, aerobic hydrogen-oxidizing bacterium, Hydrogenobacter thermophilus TK-6, eleven different organic compounds tested were only slightly oxidized compared with NADH or H₂. Glucose acetate and pyruvate could be incorporated into intact cells of strain TK-6 only in the presence of hydrogen and oxygen in an atmosphere. These two findings, both weak oxidation of organic compounds and the requirement of energy for incorporation of organic compounds, presented a partial explanation for the obligate autotrophy of Hydrogenobacter thermophilus TK-6. The addition of a small amount of pyruvate, acetate and malate to the medium, stimulated the autotrophic growth of this strain, which suggests that these three compounds mayplay important roles in the carbon metabolismof the strain.

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From a supernatant of a mixed continuous culture of Pseudomonas sp. VM15C and Pseudomonas putida VM15A, of which the former produced a poly(vinyl alcohol) (PVA)-degrading enzyme and the latter an essential growth factor (trivial name, factor A) for PVA utilization by the former, purified factor A showing homogeneity on high performance liquid chromatography was obtained. From spectral and other evidence, factor A was identified as pyrroloquinoline quinone (PQQ). PQQ was effective in not only causing growth of the PVA-degrading bacterium on PVA but also in enhancing the growth rate and the cell yield at concentrations of 0.05 to 4ng/ml. Thus, a novel coenzyme, PQQ, was reported as a bacterial growth factor for the first time.

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