Search

Histamine (HIST) and other biogenic amines found in fish and fishery products accumulated by the action of bacterial amino acid decarboxylase cannot be decomposed and eliminated by heating or other chemical methods. A simple method for HIST elimination is proposed by a coupling reaction of the fungal amine oxidase (FAO) and bacterial aldehyde oxidase (ALOX) of acetic acid bacteria. As a model reaction, FAO oxidized benzylamine to benzaldehyde, which in turn was oxidized spontaneously to benzoic acid with ALOX. Likely, in HIST elimination, FAO coupled well with ALOX to produce imidazole 4-acetic acid from HIST with an apparent yield of 100%. Imidazole 4-acetaldehyde was not detected in the reaction mixture. In the absence of ALOX, the coupling reaction was incomplete given a number of unidentified substances in the reaction mixture. The proposed coupling enzymatic method may be highly effective to eliminate toxic amines from fish and fishery products.

The aim of this study was to propose an alternative route for preparing chiral β- and α-ionols by asymmetric oxidation with a heme acquisition system A (HasA) derived from symbiotic fluorescent bacteria as a biocatalyst. The HasA (6 g) in distilled water (300 mL) was stirred at 1150 rpm for 1 day at 40°C. Subsequently, a secondary alcohol (0.77 mmol) as a substrate in 2% 2-propanol was added to the catalyst solution. After verifying that the oxidation proceeded to ca 50% using gas chromatography (GC), the reaction mixture was filtered, extracted, washed, and dried over. The extract was concentrated in vacuo and purified using silica gel column chromatography to yield the oxidized product and recover the unreacted alcohol. β-Ionol was oxidized into β-ionone in a conversion of ca. 50% in the presence of the HasA for three days, and the remaining alcohol was recovered and analyzed using chiral GC after acetylation. The HasA selectively catalyzed the asymmetric oxidation of β-ionol with a preference for the (R)- form to recover (S)-β-ionol with 96.4 ±1.6% enantiomeric excess (ee). In addition, α-ionol was similarly oxidized into α-ionone in a conversion of ca. 50% for seven days, preferentially remaining (9S)-α-ionol with 97.9 ± 0.2% ee. The characteristic aroma of (S)-β-ionol obtained by the asymmetric oxidation with the HasA showed floral and fruity like, while the aroma of (9S)-α-ionol described as violet and sweet. In this study, we successfully developed a new approach to prepare enantiomerically pure (S)-β- and α-ionols by the asymmetric oxidation with the HasA.

The aim of this study was to identify and characterize the aroma components of absolute oil from natsudaidai (Citrus natsudaidai Hayata) flowers. A total of 43 aroma components were detected in the absolute oil of natsudaidai flowers using a headspace solid phase microextraction (SPME)-gas chromatography-mass spectrometry (GC-MS). The most abundant components from the absolute oil was linalool (31.14%), followed by methyl anthranilate, γ-terpinene, p-cymene, (E)-β-ocimene, limonene, indole and α-terpineol. The configuration of linalool from the absolute oil was assigned as (S)-form and its optical purities were determined as 89.36±0.36% enantiomeric excess using a SPME-chiral GC. These results indicated that the composition of aroma components in the absolute oil would influence the overall aroma qualities of natsudaidai flowers and the physiological effects on human.

d-Mannose isomerase (EC 5.3.1.7) catalyzing reversible conversion between d-mannose and d-fructose was found in acetic acid bacteria. Cell fractionation confirmed the enzyme to be a typical membrane-bound enzyme, while all sugar isomerases so far reported are cytoplasmic. The optimal enzyme activity was found at pH 5.5, which was clear contrast to the cytoplasmic enzymes having alkaline optimal pH. The enzyme was heat stable, and the optimal reaction temperature was observed at around 40-60 °C. Purified enzyme after solubilization from membrane fraction showed the total molecular mass of 196 kDa composing of identical 4 subunits of 48 kDa. Washed cells or immobilized cells were well functional at nearly 80% of conversion ratio from d-mannose to d-fructose and reversely 20%-25% of d-fructose to d-mannose. Catalytic properties of the enzyme were discussed with respect to the biotechnological applications to high fructose syrup production from konjac taro.

This work aims to propose a pathway for the production of 2(E),4(E)-decadienal from arachidonic acid (ARA) via 11-hydroperoxide eicosanoid (11 hydroperoxyeicosatetraenoic acid, 11-HPETE) through lipoxygenase (LOX) and hydroperoxide lyase (HPL) in the brown alga, Saccharina angustata, by identifying pathway intermediates through three studies. The first study investigated the biogeneration of 2(E),4(E)-decadienal in crude homogenates of fronds (CHF), while the second and third investigated whether ARA is the precursor of the pathway and if 11-HPETE is produced from ARA as an intermediate in 2(E),4(E)-decadienal generation, respectively. The results showed that 2(E),4(E)-decadienal was formed in CHF and its concentration increased after incubation. This finding led to the hypothesis that 2(E),4(E)-decadienal is formed enzymatically via LOX-HPL and consequently its biogeneration was determined. ARA was indicated to be a precursor of the pathway since, after CHF was incubated with ARA as a substrate, the amount of aldehyde increased significantly compared with that produced by CHF without ARA and without incubation. The production of 11-HPETE from ARA was also demonstrated as an intermediate reaction in 2(E),4(E)-decadienal formation via the LOX-HPL pathway. The hydroxy isomer of 11-HPETE was produced, and ARA was incubated with homogenated fronds in combination with glutathione peroxidase and glutathione to control its stability during identification. The compound was identified as 11-HPETE because the purified isomer showed the same retention time when co-injected with the standard using an HPLC technique; moreover, the same indicated mass spectrum was obtained as that of the standard via a GC/GCMS technique. The indicated pathway and the pathway for the production of short chain aldehydes [n-hexanal, 2(E),3(Z)-nonenal and 2(E),4(E)-decadienal] from ARA and linoleic acid through theirs hydroperoxides are proposed.

Due to the indigestibility, utilization of konjac taro, Amorphophallus konjac has been limited only to the Japanese traditional konjac food. Koji preparation with konjac taro was examined to utilize konjac taro as a source of utilizable carbohydrates. Aspergillus luchuensis AKU 3302 was selected as a favorable strain for koji preparation, while Aspergillus oryzae used extensively in sake brewing industry was not so effective. Asp. luchuensis grew well over steamed konjac taro by extending hyphae with least conidia formation. Koji preparation was completed after 3-day incubation at 30°C. D-Mannose and D-glucose were the major monosaccharides found in a hydrolyzate giving the total sugar yield of 50 g from 100 g of dried konjac taro. An apparent extent of konjac taro hydrolysis at 55°C for 24 h seemed to be completed. Since konjac taro is hydrolyzed into monosaccharides, utilization of konjac taro carbohydrates may become possible to various products of biotechnological interest. Fil: Adachi, Osao. Yamaguchi University; Japón Fil: Hours, Roque Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigación y Desarrollo en Fermentaciones Industriales. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Centro de Investigación y Desarrollo en Fermentaciones Industriales; Argentina Fil: Akakabe, Yoshihiko. Yamaguchi University; Japón Fil: Arima, Hideyuki. Yamaguchi Prefectural Industrial Technology Institute; Japón Fil: Taneba, Rie. Yamaguchi Prefectural Industrial Technology Institute; Japón Fil: Tanaka, Junya. Yamaguchi Prefectural Industrial Technology Institute; Japón Fil: Kataoka, Naoya. Yamaguchi University; Japón Fil: Matsushita, Kazunobu. Yamaguchi University; Japón Fil: Yakushi, Toshiharu. Yamaguchi University; Japón

Gluconobacter frateurii CHM 43 have D-mannitol dehydrogenase (quinoprotein glycerol dehydrogenase) and flavoprotein D-fructose dehydrogenase in the membranes. When the two enzymes are functional, D-mannitol is converted to 5-keto-D-fructose with 65% yield when cultivated on D-mannitol. 5-Keto-D-fructose production with almost 100% yield was realized with the resting cells. The method proposed here should give a smart strategy for 5-keto-D-fructose production., Centro de Investigación y Desarrollo en Fermentaciones Industriales

Due to the indigestibility, utilization of konjac taro

CHM 43 have D-mannitol dehydrogenase (quinoprotein glycerol dehydrogenase) and flavoprotein D-fructose dehydrogenase in the membranes. When the two enzymes are functional, D-mannitol is converted to 5-keto-D-fructose with 65% yield when cultivated on D-mannitol. 5-Keto-D-fructose production with almost 100% yield was realized with the resting cells. The method proposed here should give a smart strategy for 5-keto-D-fructose production.

The aim of this work was to study the physicochemical and kinetic properties of chlorogenate hydrolase (CHase) (EC 3.1.1.42) of Aspergillus niger AKU 3302 by induction in the presence of yerba mate extract. The data obtained could be applicable directly to mass processing for a plant scale production of quinic acid (QA) and caffeic acid (CA) with koji CHase. It is fundamentally significant to accumulate catalytic properties of CHase as much as possible with crude CHase, when koji CHase is directed to practical industrial processing of breakdown of chlorogenate (CGA). CHase exhibited a high thermal stability without appreciable loss after standing for 6 h at 50 °C and was stable in wide pH ranges from 2.0 to 9.0. The optimum pH and temperature of CHase activity were found at 6.5–7.0 and 45 °C, respectively. The Vmax and Km values for CGA hydrolysis were 1.996 unit mg−1 and 0.72 mM, respectively. The activation energy of CHase was estimated to be 26 kJ mol−1. Thus, CHase induced with CGA revealed successful for the production of CA and QA, fine chemicals of high interest and commercial values, from natural plant resources rich in CGA such as yerba mate. Several advantageous merits obtained with a crude CHase for the practical formation of QA and CA from yerba mate or yerba mate extract are discussed. Fil: Butiuk, Ana Paula. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigación y Desarrollo en Fermentaciones Industriales. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Centro de Investigación y Desarrollo en Fermentaciones Industriales; Argentina. Universidad Nacional de Misiones. Facultad de Ciencias Exactas, Químicas y Naturales; Argentina Fil: Maidana, Silvana Andrea. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste; Argentina. Universidad Nacional de Misiones. Facultad de Ciencias Exactas, Químicas y Naturales; Argentina Fil: Martos, María Alicia. Universidad Nacional de Misiones. Facultad de Ciencias Exactas, Químicas y Naturales; Argentina Fil: Akakabe, Yoshihiko. Yamaguchi University; Japón Fil: Adachi, Osao. Yamaguchi University; Japón Fil: Hours, Roque Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigación y Desarrollo en Fermentaciones Industriales. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Centro de Investigación y Desarrollo en Fermentaciones Industriales; Argentina

An essential oil from dried "wakame" (Undaria pinnatifida), prepared by a simultaneous distillation extraction method, was analyzed by GC-MS, indicating the presence of one major component of volatiles. The volatile component was identified as (6Z,9Z,12Z,15Z,18Z)-1,6,9,12,15,18-henicosahexaene by comparison with the GC-MS and NMR spectra of synthetic. The henicosahexaene showed a subtly marine aroma. (6Z,9Z,12Z,15Z)-1,6,9,12,15-Henicosapentaene was also detected as a minor polyene in the essential oils. It was suggested that these polyenes contribute to the characteristic aroma of the dried wakame.

An essential oil from the brown alga Sargassum thunbergii, prepared by a simultaneous distillation extraction method, contained in two types of volatile polyenes with a terminal double bond such as (6Z,9Z,12Z,15Z,18Z)-1,6,9,12,15,18-henicosahexaene and (6Z,9Z,12Z,15Z)-1,6,9,12,15-henicosapentaene and with their saturated terminal structures such as (3Z,6Z,9Z,12Z,15Z,18Z)-3,6,9,12,15,18-henicosahexaene and (3Z,6Z,9Z,12Z,15Z)-3,6,9,12,15-henicosapentaene. These volatile polyenes were identified by comparison with the GC-MS and NMR spectra of synthetics. The polyenes with the saturated terminal structures were found in the brown algae for the first time.

Chlorogenic acid (CGA) and its hydrolysis products, quinic and caffeic acids are considered as fine chemicals and have a high commercial value. Yerba mate stems, useless residue from yerba mate processing, contains significant amounts of CGA. The goal of this study was to determine the best conditions for maximizing the CGA aqueous extraction from residues of yerba mate processing and to fit the extraction kinetics to empirical models. The effect of single factors such as solid-liquid ratio, numbers of extraction, temperature and time were studied for two particle sizes, using one factor at a time method and Response Surface Methodology (RSM). The highest and almost instantaneous CGA extraction (1.051 ± 0.015 gCGA L−1) was obtained using O particle size particle size >1 × 5 mm) the optimized conditions were 85 ± 5 °C and 25 ± 5 min, solid-liquid ratio of 1:20 and double stage extraction. For these last particles, the applied models of Pilosof et al. and Spiro and Jago showed a good agreement with the experimental and model calculated data. In the present study, it was possible to optimize the CGA extraction conditions for two particle sizes of yerba mate stems, in order to obtain extracts with high content of CGA that can be used in the production of others fine chemicals of interest in pharmaceutical industries.

Mitochondria, which evolved from a free-living bacterial ancestor, contain their own genomes and genetic systems and are produced from preexisting mitochondria by binary division. The mitochondrion-dividing (MD) ring is the main skeletal structure of the mitochondrial division machinery. However, the assembly mechanism and molecular identity of the MD ring are unknown. Multi-omics analysis of isolated mitochondrial division machinery from the unicellular alga Cyanidioschyzon merolae revealed an uncharacterized glycosyltransferase, MITOCHONDRION-DIVIDING RING1 (MDR1), which is specifically expressed during mitochondrial division and forms a single ring at the mitochondrial division site. Nanoscale imaging using immunoelectron microscopy and componential analysis demonstrated that MDR1 is involved in MD ring formation and that the MD ring filaments are composed of glycosylated MDR1 and polymeric glucose nanofilaments. Down-regulation of MDR1 strongly interrupted mitochondrial division and obstructed MD ring assembly. Taken together, our results suggest that MDR1 mediates the synthesis of polyglucan nanofilaments that assemble to form the MD ring. Given that a homolog of MDR1 performs similar functions in chloroplast division, the establishment of MDR1 family proteins appears to have been a singular, crucial event for the emergence of endosymbiotic organelles.

A novel oxidation of D-pentonates to 4-keto-D-pentonates was analyzed with Gluconobacter Thailandicus NBRC 3258. D-Pentonate 4-dehydrogenase activity in the membrane fraction was readily inactivated by EDTA and it was reactivated by the addition of PQQ and Ca2+. D-Pentonate 4-dehydrogenase was purified to two different subunits, 80 and 14 kDa. The absorption spectrum of the purified enzyme showed no typical absorbance over the visible regions. The enzyme oxidized D-pentonates to 4-keto-D-pentonates at the optimum pH of 4.0. In addition, the enzyme oxidized D-fructose to 5-keto-D-fructose, D-psicose to 5-keto-D-psicose, including the other polyols such as, glycerol, D-ribitol, D-arabitol, and D-sorbitol. Thus, D-pentonate 4-dehydrogenase was found to be identical with glycerol dehydrogenase (GLDH), a major polyol dehydrogenase in Gluconobacter species. The reaction versatility of quinoprotein GLDH was notified in this study., Facultad de Ciencias Exactas, Centro de Investigación y Desarrollo en Fermentaciones Industriales

An essential oil from the brown alga Sargassum thunbergii, prepared by a simultaneous distillation extraction method, contained in two types of volatile polyenes with a terminal double bond such as (6Z,9Z,12Z,15Z,18Z)-1,6,9,12,15,18-henicosahexaene and (6Z,9Z,12Z,15Z)-1,6,9,12,15-henicosapentaene and with their saturated terminal structures such as (3Z,6Z,9Z,12Z,15Z,18Z)-3,6,9,12,15,18-henicosahexaene and (3Z,6Z,9Z,12Z,15Z)-3,6,9,12,15-henicosapentaene. These volatile polyenes were identified by comparison with the GC-MS and NMR spectra of synthetics. The polyenes with the saturated terminal structures were found in the brown algae for the first time.

An essential oil from dried "wakame" (Undaria pinnatifida), prepared by a simultaneous distillation extraction method, was analyzed by GC-MS, indicating the presence of one major component of volatiles. The volatile component was identified as (6Z,9Z,12Z,15Z,18Z)-1,6,9,12,15,18-henicosahexaene by comparison with the GC-MS and NMR spectra of synthetic. The henicosahexaene showed a subtly marine aroma. (6Z,9Z,12Z,15Z)-1,6,9,12,15-Henicosapentaene was also detected as a minor polyene in the essential oils. It was suggested that these polyenes contribute to the characteristic aroma of the dried wakame.

Membrane-bound, pyrroloquinoline quinone (PQQ)-dependent glycerol dehydrogenase (GLDH, or polyol dehydrogenase) of Gluconobacter sp. oxidizes various secondary alcohols to produce the corresponding ketones, such as oxidation of D-sorbitol to L-sorbose in vitamin C production. Substrate specificity of GLDH is considered limited to secondary alcohols in the D-erythro configuration at the next to the last carbon. Here, we suggest that L-ribose, D- and L-lyxoses, and L-tagatose are also substrates of GLDH, but these sugars do not meet the substrate specificity rule of GLDH. The oxygen consumption activity of wild-type Gluconobacter frateurii cell membranes depends on several kinds of sugars as compared with that of the membranes of a GLDH-negative variant. Biotransformation of those sugars with the membranes was examined to determine the reaction products. A time course measuring the pH in the reaction mixture and the increase or decrease in substrates and products on TLC suggested that oxidation products of L-lyxose and L-tagatose were ketones with unknown structures, but those of L-ribose and D-lyxose were acids. The oxidation product of L-ribose was purified and revealed to be L-ribonate by HRMS and NMR analysis. Biotransformation of L-ribose with the membranes and also with the whole cells produced L-ribonate in nearly stoichiometric amounts, indicating that the specific oxidation site in L-ribose is recognized by GLDH. Since purified GLDH produced L-ribonate without any intermediate-like compounds, we propose here a reaction model where the first carbon in the pyranose form of L-ribose is oxidized by GLDH to L-ribonolactone, which is further hydrolyzed spontaneously to produce L-ribonate.

Eight-carbon (C8) volatiles, such as 1-octen-3-ol, octan-3-one, and octan-3-ol, are ubiquitously found among fungi and bryophytes. In this study, it was found that the thalli of the common liverwort Marchantia polymorpha, a model plant species, emitted high amounts of C8 volatiles mainly consisting of (R)-1-octen-3-ol and octan-3-one upon mechanical wounding. The induction of emission took place within 40min. In intact thalli, 1-octen-3-yl acetate was the predominant C8 volatile while tissue disruption resulted in conversion of the acetate to 1-octen-3-ol. This conversion was carried out by an esterase showing stereospecificity to (R)-1-octen-3-yl acetate. From the transgenic line of M. polymorpha (des6(KO)) lacking arachidonic acid and eicosapentaenoic acid, formation of C8 volatiles was only minimally observed, which indicated that arachidonic and/or eicosapentaenoic acids were essential to form C8 volatiles in M. polymorpha. When des6(KO) thalli were exposed to the vapor of 1-octen-3-ol, they absorbed the alcohol and converted it into 1-octen-3-yl acetate and octan-3-one. Therefore, this implied that 1-octen-3-ol was the primary C8 product formed from arachidonic acid, and further metabolism involving acetylation and oxidoreduction occurred to diversify the C8 products. Octan-3-one was only minimally formed from completely disrupted thalli, while it was formed as the most abundant product in partially disrupted thalli. Therefore, it is assumed that the remaining intact tissues were involved in the conversion of 1-octen-3-ol to octan-3-one in the partially disrupted thalli. The conversion was partly promoted by addition of NAD(P)H into the completely disrupted tissues, suggesting an NAD(P)H-dependent oxidoreductase was involved in the conversion.

Production of 4-keto-D-arabonate (4KAB) was confirmed in a culture medium of Gluconacetobacter liquefaciens strains, newly isolated from water kefir in Argentina. The strains rapidly oxidized D-glucose, Dgluconate (GA), and 2-keto-D-gluconate (2KGA), and accumulated 2,5-diketo-D-gluconate (25DKA) exclusively before reaching the stationary phase. 25DKA was in turn converted to 4KAB, and 4KAB remained stable in the culture medium. The occurrence of 4KAB was assumed by Ameyama and Kondo about 50 years ago in their study on the carbohydrate metabolism of acetic acid bacteria (Bull. Agr. Chem. Soc. Jpn., 22, 271-272, 380-386 (1958)). This is the first report confirming microbial production of 4KAB., Centro de Investigación y Desarrollo en Fermentaciones Industriales

The citrus fruit Setomi is a hybrid of Yoshiura ponkan (Citrus reticulate Blanco) and Kiyomi (Citrus unshiu Mrcov. x Citrus sinensis Osbeck). The essential oils from the peel of Setomi and its parent cultivars were obtained by a simultaneous distillation extraction technique. Comparing the essential oils of Setomi and its parent cultivars, it was found that the oil in the peel of Setomi consisted of characteristic aroma components from each parent cultivar. The principal component analysis of data, obtained with an electronic nose, indicated that the odor quality of Setomi was different from those of the parent cultivars.

Chemical communications play an important role in plants, fungi, and algae. Volatile organic compounds in marine algae are released into the seawater. These compounds play a role as either pheromones or allelochemicals. We observed that the turbinid gastropod Lunella coronata coreensis inhabits the intertidal zone and often grazes the green alga Ulva pertusa. Feeding tests and feeding preference studies were performed with green, brown and red algae or by using the powdered freeze-dried seaweed in agar. The snails fed on U. pertusa preferentially compared to the other marine algae, and recognized chemoreception compounds from the alga but not their structural or morphological differences. From feeding tests using artificial foods, it is suggested that the feeding attractants are in the essential oil of the alga U. pertusa.

After mechanical wounding of the marine green alga Bryopsis maxima in a phosphate buffer, one main organic component was released to the solution. The organic compound was characterized by a molecular ion at 238 m/z by gas chromatography-mass spectrometry (GC-MS) and was deduced as 8-heptadecene by the fragment pattern. To identify the stereochemistry of 8-heptadecene, synthetic (Z/E)-8-heptadecene was coinjected to the solution of wounded B. maxima. Comparing retention times and mass spectra with the synthetic sample, the target hydrocarbon obtained from wounded B. maxima was coincident with (Z)-8-heptadecene.

2E-Nonenal and n-hexanal are the major and minor flavor compounds in the edible brown alga, Laminaria angustata, respectively. They are believed to characterize the flavor of this alga. However the metabolism of the two compounds is not precisely known. The pathways were clarified by elucidation of the intermediate structure through purification of the intermediate compounds from an enzymatic reaction and identification using HPLC and GC-MS techniques. Formation of n-hexanal, 3Z-nonenal and 2E-nonenal are proposed to be via two cascades from unsaturated fatty acids. They are C18:2(n-6), linoleic acid cascade and C20:4(n-6), arachidonic acid cascade through their hydroperoxides as intermediates by the lipoxygenase/fatty acid hydroperoxide lyase pathway.

Plant fatty acid alpha-dioxygenases (DOXs) catalyze the stereospecific conversion of fatty acids into the corresponding (R)-2-hydroperoxy fatty acids. In several plant species the corresponding gene was shown to be induced by pathogen infection, herbivore attack and environmental stresses. The precise signaling pathway accountable for the induction remains unidentified. In the present study, the effects of bacterial infection, oxidative- and heavy metal-stresses, and plant signaling molecules such as jasmonate, salicylic acid (SA), and ethylene (ET) on expression of a fatty acid alpha-DOX (OsDOX) gene in rice seedlings were investigated. The rice blight bacteria, Xanthomonas oryzae, elicited the accumulation of OsDOX transcripts in the leaves in both the incompatible and compatible interactions. Treating the seedling with CuSO4 also significantly enhanced the OsDOX expression. The degree of induction was shown to be mostly parallel to the level of endogenous jasmonic acid (JA) in the leaves. In contrast, SA was little effective and ET down-regulated not only the OsDOX expression but also the endogenous level of JA in rice seedlings. These results suggested that the OsDOX gene expression by a variety of stress-related stimuli was activated through jasmonate signaling and was negatively regulated by ET.

D-Ribose and 2-deoxy-D-ribose were oxidized to 4- keto-D-ribonate and 2-deoxy-4-keto-D-ribonate respectively by oxidative fermentation, and the chemical structures of the oxidation products were confirmed to be as expected. Both pentoses are important sugar components of nucleic acids. When examined, purine nucleosidase activity predominated in the membrane fraction of acetic acid bacteria. This is perhaps the first finding of membrane-bound purine nucleosidase., Centro de Investigación y Desarrollo en Fermentaciones Industriales

Both enantiomers of (3S)-(-)- and (3R)-(+)-Neodictyoprolenol [(3S,5Z,8Z)-(-)-1,5,8-unde-catrien- 3-ol] were successfully converted to the algal sex pheromone, (1S,2R)-(-)-dictyopterene B and (1R,2S)-(+)-dictyopterene B in high enantiomeric purities (e.e. > 99%), respectively, by the biomimetic reaction involving phosphorylation and elimination under a mild condition

Long-chain fatty acids can be metabolized to C n −1 aldehydes by α-oxidation in plants. The reaction mechanism of the enzyme has not been elucidated. In this study, a complete nucleotide sequence of fatty acid α-oxygenase gene in rice plants (Oryza sativa) was isolated. The deduced amino acid sequence showed some similarity with those of mammalian prostaglandin H synthases (PGHSs). The gene was expressed in Escherichia coli and purified to apparently homogenous state. It showed the highest activity with linoleic acid and predominantly formed 2-hydroperoxide of the fatty acid (C n ), which is then spontaneously decarboxylated to form corresponding C n −1 aldehyde. With linoleic or linoleic acids as a substrate, rice α-oxygenase formed no product having aλ max at approximately 234 nm, which indicated that the enzyme could not oxygenize the pentadiene system in the substrate. The spectroscopic feature of the purified enzyme in its ferrous state is similar to that of mammalian PGHS, whereas that of dithionite-reduced state showed significant difference. Site-directed mutagenesis revealed that His-158, Tyr-380, and Ser-558 were essential for the α-oxygenase activity. These residues are conserved in PGHS and known as a heme ligand, a source of a radical species to initiate oxygenation reaction and a residue involved in substrate binding, respectively. This finding suggested that the initial step of the oxygenation reaction in α-oxygenase has a high similarity with that of PGHS. The rice α-oxygenase activity was inhibited by imidazole but hardly inhibited by nonsteroidal anti-inflammatory drugs, such as aspirin, ibuprofen, and flurbiprofen, which are known as typical PGHS inhibitors. In addition, peroxidase activity could not be detected with α-oxygenase when palmitic acid 2-hydroperoxide was used as a substrate. From these findings, the catalytic resemblance between α-oxygenase and PGHS seems to be evident, although there still are differences in their substrate recognitions and peroxidation activities.

4-Keto-D-arabonate (D-threo-pent-4-ulosonate) and 4-keto-D-ribonate (D-erythro-pent-4-ulosonate) were prepared from D-arabinose and D-ribose by two successive reactions of membrane-bound enzymes, D-aldopentose 4-dehydrogenase and 4-keto-D-aldopentose 1-dehydrogenase of Gluconobacter suboxydans IFO 12528. Alternatively, they were prepared from D-arabonate and D-ribonate with another membrane-bound enzyme, D-pentonate 4-dehydrogenase. Analytical data confirmed the chemical structures of the 4-pentulosonates prepared. This is the first report of successful enzymatic synthesis of 4-pentulosonates.

Plants receive volatile compounds emitted by neighboring plants that are infested by herbivores, and consequently the receiver plants begin to defend against forthcoming herbivory. However, to date, how plants receive volatiles and, consequently, how they fortify their defenses, is largely unknown. In this study, we found that undamaged tomato plants exposed to volatiles emitted by conspecifics infested with common cutworms (exposed plants) became more defensive against the larvae than those exposed to volatiles from uninfested conspecifics (control plants) in a constant airflow system under laboratory conditions. Comprehensive metabolite analyses showed that only the amount of (Z)-3-hexenylvicianoside (HexVic) was higher in exposed than control plants. This compound negatively affected the performance of common cutworms when added to an artificial diet. The aglycon of HexVic, (Z)-3-hexenol, was obtained from neighboring infested plants via the air. The amount of jasmonates (JAs) was not higher in exposed plants, and HexVic biosynthesis was independent of JA signaling. The use of (Z)-3-hexenol from neighboring damaged conspecifics for HexVic biosynthesis in exposed plants was also observed in an experimental field, indicating that (Z)-3-hexenol intake occurred even under fluctuating environmental conditions. Specific use of airborne (Z)-3-hexenol to form HexVic in undamaged tomato plants reveals a previously unidentified mechanism of plant defense.

SUMMARY: When long-chain saturated and unsaturated fatty acids were incubated with crude enzyme of marine green alga Ulva pertusa, the corresponding (R)-2-hydroperoxy acids were found to have high enantiomeric excess (> 99%). In a similar administration experiment, the (R)-2-hydroperoxy acid was obtained from the incubation of palmitic acid with crude enzymes of a variety of marine algae. Thus, we found that not only green algae but also brown and red algae are capable of enantioselective 2-hydroperoxylation of palmitic acid.

Genes encoding an alpha-oxygenase, in Nicotiana tabacum and Arabidopsis thaliana, have been recently isolated. However, the reaction mechanism of the enzyme has not so far been elucidated. In this study, a cDNA encoding the fatty acid alpha-oxygenase gene in rice plants was isolated. The deduced amino acid sequence showed high similarity (63.6%) to that of N. tabacum. The gene was cloned into an expression vector system, pQE-30, and expressed in Escherichia coli as a host cell. Palmitic acid as a substrate was incubated with the lysate of the cells, and the products were analysed by HPLC. A compound formed predominantly by the recombinant enzyme was shown to be n-pentadecanal. By incubating the mixture at 0 degrees C, 2-hydroperoxypalmitic acid was detected as a primary product and little formation of n-pentadecanal was detected. Furthermore, uptake of molecular oxygen was observed with an oxygen electrode. This indicated that the gene in rice plants encodes the alpha-oxygenase.

Neodictyoprolenol [(-)-(S)-(1,5Z,8Z)-undecatrien-3-ol], dictyoprolenol [(-)-(S )-(1,5Z)- undecadien-3-ol] and their acetates neodictyoprolene [(+)-(5)-3-acetoxy-(1,5Z,8Z)-undecatriene] and dictyoprolene [(+)-(S)-3-acetoxy-(1,5Z)-undecadiene], which are interesting as possible biosynthetic intermediates of the sex pheromones (dictyopterene B, C′ and D′) of brown algae, were synthesized by chemo-enzymatic methods through optical resolution of racemic neodictyoprolenol and dictyoprolenol using two lipases; Amano PS (Pseudom onas sp.) and Novozym 435® (Candida sp.). A combination of acylation of the alcohols and hydrolysis of the acetates by Novozym 435® produced neodictyoprolenol, neodictyoprolene, dictyoprolenol and dictyoprolene with high optical purities over 99% enantiomeric excess (e.e.). This snythetic methods will make it easier to search these compounds in marine algae and to study their biosynthesis.

When palmitic acid was incubated with crude enzyme of marine green alga Ulva pertusa, (R)-2-hydroperoxyhexadecanoic acid was formed in high enantiomeric purity (>99%ee).

Long-chain aldehydes (LCA), such as pentadecanal (PD), (8Z,11Z)-heptadecadienal (HDD) and (8Z,11Z,14Z)-heptadecatrienal (HDT), were identified in the essential oils obtained from fresh green tobacco leaves (Nicotiana tabacum cv. BY2 and N. tabacum cv. MC). PD, HDD and HDT were found to be produced enzymatically from palmitic acid (PA), linoleic acid and α-linolenic acid, respectively. LCA-forming activity for PA changed during growth of tobacco leaves and was highest at flowering time.

A growth-promoting substance (GPS) for methylotrophic yeasts was purified from yeast extract. The purified GPS showed growth promotion by reducing the lag time of the growth of methylotrophic Candida boidinii, while the growth rate at the exponential phase was the same as that of growth without GPS. GPS was finally identified to be L-proline by the criteria of instrumental analysis and chemical shift assignments.

(−)-( 3R,4R )-3-Butyl-4-vinylcyclopentene [(−)- 1 ] was synthesized via (+)-( 1S,5R )-3-oxabicyclo [3,3,0] oct-6-en-2-one. Synthetic (−)- 1 coincided with the peak with later retention time of racemic (±)- 1 in a chiral GC (CP-Cyclodex 236M), while the natural 1 in essential oils from the marine brown algae, Dictyopteris prolifera and D . sp. was identical with the earlier retention time peak. Thus, the absolute configuration of the natural product in Dictyopteris oils was determined as (+)-( 3S,4S ) with ca 100% enantiomeric excess.

Eikenella corrodens produces autoinducer-2 (AI-2) in the mid log phase, and AI-2 activity decreases dramatically during the stationary phase. We investigated the mechanism underlying this decrease in AI-2 activity. To analyze the mechanism, we extracted and purified AI-2 from the supernatant of mid-log-phase culture. Simultaneously, the stationary-phase culture supernatant was fractionated by ammonium sulfate precipitation. On incubating purified AI-2 and 4-hydroxy-5-methyl-3(2H)-furanone (MHF) with each fraction, the 30% fraction decreased both AI-2 and MHF activities. The data suggest that AI-2 and MHF were rendered inactive in the same manner. Heat and/or trypsin treatment of the 30% fraction did not completely arrest AI-2 inactivation, suggesting that partially heat-stable proteins are involved in AI-2 inactivation. We observed that an enzyme converted MHF to another form. This suggests that E. corrodens produces an AI-2 inactivating enzyme, and that AI-2 can be degraded or modified by it.

Chemical structure-odor correlations in the isomers of n-C9-methylene interrupted dienols were explored using synthetic nine isomers of these alcohols. The synthetic dienols were purified by recrystallization or column chromatography of their 3,5-dinitrobenzoate de­ rivatives. Chemical structure-odor correlations in all the isomers of the purified n-nonadien-1-ols were analyzed by treating the data obtained statistically with the principal component analysis method (Sakoda et al., 1995; Cramer et al., 1988) in comparison with those of n-nonen-1-ols. The odor profiles of the n-nonadien-1-ols were attributable largely to the geometries of the isomers, compared with n-nonen -1-ols (Sakoda et al., 1995). With the principal component analysis, the odor profiles of the series of the dienols were successfully integrated into the first and the second principal components. The first component (PC 1) consisted of combined characteristics of fruity, fresh, sweet, herbal and oily-fatty, and the second component (PC 2) leaf or grassy and vegetable-like. Of the methylene interrupted dienol isomers, (2E ,6Z)-and (3Z,6Z)-nonadien-1-ols which are natural products and have (6Z) in the same, deviated markedly from the other isomers as seen in (6Z)-nonen -1-ol of n-nonen-1-ols. That suggests that the double bond of (ω3Z) was an important factor for natural characteristic odor.

In order to confirm the biosynthetic pathway to 1-octen-3-ol from linoleic acid, a crude enzyme solution was prepared from the edible mushroom, Lentinus decadetes. When the reaction was performed in the presence of glutathione peroxidase, which can reduce organic hydroperoxide to the corresponding hydroxide, the amount of 1-octen-3-ol formed from linoleic acid was decreased. At the same time, an accumulation of linoleic acid 10-hydroxide could be detected. The 10-hydroperoxide therefore seems to be an intermediate on the biosynthetic pathway.

Immobilized cells of Daucus carota transformed acetophenone into (S)-α-phenethyl alcohol by a stereoselective reduction pathway. Immobilized cells of Nicotiana tabacum also transformed the same substrate into the (S)-alcohol, but neither stereoselective reduction nor stereoselective oxidation was observed in the biotransformation process. (R)- and (S)-α-phenethyl alcohol of a high enantiomeric purity of > 99% ee can be prepared by the biotransformation of acetophenone with immobilized cells of Gardenia jasminoides and Daucus carota.

When linoleic and linolenic acid were incubated with a crude enzyme of marine green alga Ulva conglobata, the corresponding (R)-9-hydroperoxy-(10E, 12Z)-10, 12-octadecadienoic acid [(R)-9-HPODE] and (R)-9-hydroperoxy-(10E, 12Z, 15Z)-10, 12, 15-octadecatrienoic acid [(R)-9-HPOTrE] were formed with a high enantiomeric excess (>99%), respectively.

In our previous study, a new microbial reaction yielding 4-keto-D-arabonate from 2,5-diketo-D-gluconate was identified with Gluconacetobacter liquefaciens RCTMR 10. It appeared that decarboxylation and dehydrogenation took place together in the reaction. To analyze the nature of the reaction, investigations were done with the membrane fraction of the organism, and 4-keto-D-arabinose was confirmed as the direct precursor of 4-keto-D-arabonate. Two novel membrane-bound enzymes, 2,5-diketo-D-gluconate decarboxylase and 4-keto-D-aldopentose 1-dehydrogenase, were involved in the reaction. Alternatively, D-arabonate was oxidized to 4-keto-D-arabonate by another membrane-bound enzyme, D-arabonate 4-dehydrogenase. More directly, D-arabinose oxidation was examined with growing cells and with the membrane fraction of G. suboxydans IFO 12528. 4-Keto-D-arabinose, the same intermediate as that from 2,5-diketo-D-gluconate, was detected, and it was oxidized to 4-keto-D-arabonate. Likewise, D-ribose was oxidized to 4-keto-D-ribose and then it was oxidized to 4-keto-D-ribonate. In addition to 4-keto-D-aldopentose 1-dehydrogenase, the presence of a novel membranebound enzyme, D-aldopentose 4-dehydrogenase, was confirmed in the membrane fraction. The formation of 4-keto-D-aldopentoses and 4-keto-D-pentonates (4-pentulosonates) was finally confirmed as reaction products of four different novel membrane-bound enzymes., Centro de Investigación y Desarrollo en Fermentaciones Industriales