吉田 充

In this study, the genome sequences of two Basidiomycetous yeasts, Tremella yokohamensis and Tremella fuciformis , which have very similar morphological characteristics, were determined. The genomic sequence data obtained will be useful for understanding the taxonomy and metabolic-related genes of basidiomycete yeasts.

Wild boar meat containing radioactive cesium (Cs) of approximately 1000 Bq/kg (134Cs+137Cs) was processed into bacon, sausage, and ham. In order to understand the concentration and quantity change of radioactive Cs, processing factor (Pf) and food processing retention factor (Fr) were calculated. The radioactive Cs quantity in the meat did not reduce during smoking. The dehydration-related meat mass reduction during smoking without decrease of radioactive Cs led to Cs condensation in the bacon compared with the raw rib meat before processing, resulting in a Pf of 1.18. Soaking in liquid, such as pickling in liquid and desalting or boiling in water, effectively removed radioactive Cs by leakage into water. Therefore, the Fr value of the boiled ham produced from a loin meat block through the above-described three liquid-soaking processes was 0.27. The Pf value of the boiled ham was 0.30 due to the meat block mass reduction after boiling as the result of dehydration along with the protein thermal denaturation-related muscle tissue shrinkage. The steamed ham Fr value was 0.53 since the removal of the radioactive Cs was less efficient by steaming than by boiling. The Pf value of the steamed ham was 0.54, almost the same as the Fr value, as the mass decrease rate was the same as the radioactive Cs decrease rate by steaming. The Fr and the Pf values of the boiled sausage, of which processing did not include soaking in the pickling liquid, were 0.64 and 0.62, respectively. The steaming of the sausage meat did not remove radioactive Cs during the dehydration-related mass reduction leading to Fr and Pf values of 1.01 and 1.17, respectively. As the result of this study, processing to boiled ham was the most effective measure for reducing both radioactive Cs quantity and concentration in raw meat. Processing to bacon and steamed sausage showed no Cs quantity reduction with the moisture loss resulting in Cs condensation compared to the raw material.

In this study, we investigated the possibility of the geographical origin discrimination between Japanese and Mexican kabocha pumpkin using δ13C and δ18O in lyophilized raw flesh. Kabocha harvested in Hokkaido, the major kabocha production area in Japan, could be discriminated against not only that grown in Mexico but also that in New Zealand. However, seasoning after cooking or processing affected the δ13C and the δ18O values. Crude fiber extraction eliminated the effect of seasonings and enabled the adoption of the δ13C and δ18O values in crude fiber for the geographical origin verification of kabocha even after cooking and processing. The usage of δ13C and the δ18O in crude fiber would extend the application possibilities of stable isotope analysis in the geographical origin determination of various cooked and processed vegetables and fruits as well as raw materials.

Theaflavin, a polyphenol responsible for the bright orange color and various bioactivities of black tea exudates, is susceptible to autoxidation at neutral and mild alkaline pH, changing its color to brown. In the presence of cysteine (Cys), glutathione (GSH), or N-acetyl cysteine (NAC), the browning of theaflavin solution was inhibited concomitantly with time-dependent decreases in the concentrations of both theaflavin and thiol group. The rank order of the decrease was Cys ≅ GSH > NAC, suggesting the relevance of the nucleophilic property of the thiol group to its reaction with theaflavin. LC-MS analysis of the reaction products indicated formation of novel derivatives that were mono- or di-molecular adducts of thiol compounds. We determined the chemical structures of theaflavin-Cys and theaflavin-GSH adducts by NMR and proposed the reaction mechanisms. It was found that the theaflavin-Cys adduct was not a simple adduct, to which a new cyclic structure was added.

Aldose–ketose isomerization is commonly used to prepare rare oligosaccharides such as maltulose (4-O-α-D-glucopyranosyl-D-fructose) and lactulose (4-O-β-D-galactopyranosyl-D-fructose). However, both sugars are degraded under alkaline conditions via β-elimination, while their subsequent benzylic acid rearrangement leads to the formation of isosaccharinic acids. Here, we investigated the behavior of maltose and maltulose upon heating in phosphate buffer solution at pH 7.5. Maltose was initially isomerized into maltulose. Maltulose was degraded via β-elimination, followed by keto–enol tautomerization, which led to the formation of a 1,3-dicarbonyl intermediate bearing an aldehyde group at the C-1 position and a ketone group at the C-3 position. Subsequent hydrolysis of this intermediate afforded formic acid and 3-deoxy-D-glycero-pent-2-ulose (1) as the major products based on HPLC and NMR data. In contrast, the formation of isosaccharinic acid via benzylic acid rearrangement, not the 3-deoxypentulose, was reported under the strongly alkaline conditions (Knill and Kennedy, 2003). The heat treatment of 1→4 linked oligo- and polysaccharides possessing glucose or fructose residue at the reducing end under neutral pH conditions could be applied for the practical preparation of a 3-deoxypentulose.

Two new alkaloids, oryzamutaic acid K and oryzadiamine C, were isolated from the yellow endosperm of an Oryza sativa mutant. The structures of oryzamutaic acid K and oryzadiamine C were elucidated with spectroscopic analyses. Oryzamutaic acid K and oryzadiamine C are new C23N4- and C19N3-type alkaloids, respectively, that possess nitrogen-containing heterocyclic ring systems. Oryzadiamine C may play a significant role in the yellow color of the endosperm. (C) 2020 The Author(s). Published by Elsevier Ltd.

Lengthwise grooving was adopted to produce quick boil spaghetti with standard thicknesses after boiling. Ordinary dried spaghetti with a 1.6 mm diameter (Sample A, 7 min boiling time) was compared to quick boil spaghetti samples, namely spaghetti with a V-shaped groove (Sample B, 4 min boiling time) and spaghetti with three windmill-shaped grooves (Sample C, 3 min boiling time). The quick boil spaghetti samples had lower moisture content (58-59 g/100 g) than Sample A (63 g/100 g) after cooking. The spin-spin relaxation time (T-2) magnetic resonance images during boiling showed that the region around the tips of their grooves absorbed water and swelled particularly rapidly resulting in closure of the grooves. While the region with low moisture content at the core of the strand after boiling was round in Sample A, those in Sample B and C were U-shaped and like a triangle, respectively. The shearing test force-strain curves of boiled Sample B and C varied depending on the shearing direction, which reflected their non-concentric moisture distributions. The high moisture region at the boiled spaghetti surface did not have a large effect on the mechanical properties. (C) 2017 Elsevier Ltd. All rights reserved.

<p>Acrylamide has neurotoxicity, carcinogenicity, and genotoxicity in experimental animals and cellular systems. Fried potato is one of the major intake sources of acrylamide in food, and fried onion was reported to contain up to 100 ng/g level of acrylamide. To determine acrylamide concentration in potato and onion stir-fried prior to boiling for simmered dishes such as curry, stew, and Niku-jaga, a typical Japanese meat/potato/onion cuisine, we collected samples stir-fried at homes of volunteers who intended voluntarily to cook these simmered dishes. Acrylamide level was analyzed by GC-MS after the xanthydrol derivatization. Among 53 stir-fried potato samples, median and average values of acrylamide were found to be 2.0 ng/g and 11 ng/g, respectively. Acrylamide levels of 27 samples (51%) were less than limit of detection (LOD) (4 ng/g), and those of 13 samples (25%) were less than limit of quantification (LOQ) (10 ng/g). In cases with less than LOD and less than LOQ of acrylamide levels, one-half of LOD and average of LOD and LOQ were adopted, respectively, to calculate the median and average. This median was markedly lower than those of fried potato (180 ng/g) and potato snacks including potato chips (550 ng/g) reported in monitoring in 2013 fiscal year in Japan. Among 58 stir-fried onion samples, acrylamide level of only one sample (2%) was less than LOD (3 ng/g), and those of 15 samples (26%) were less than LOQ (8 ng/g). The median and average values in the stir-fried onion were 14 ng/g and 36 ng/g, respectively. These values are comparable to those for stir-fried onion reported by Ministry of Agriculture, Forestry and Fisheries, Japan (median 19 ng/g, average 25 ng/g). But the maximum value of stir-fried onion 420 ng/g in the present study is much higher than the reported maximum value (70 ng/g).</p>

試料中の放射能分布の不均一性がゲルマニウム半導体検出器による放射性セシウム濃度（134Csと137Csの濃度の合算値）の測定値に及ぼす影響を，実際の食品試料を用いて調査した．放射性セシウムを含む玄米，玄ソバ，大豆試料をそれぞれ，空隙を模擬した放射性セシウムを含まないビーズとともに，2 Lマリネリ容器に充填した．測定容器中における空隙の偏在は，放射性セシウム濃度の測定値に大きな影響を与え，容器内に空隙なく放射性セシウムを含む試料を充填した場合や放射性セシウムを含まないビーズを均一に分散させた場合と比べて，容器下部にビーズが集中すると測定値は低くなる傾向が示された．一方，上部にビーズが集中すると測定値が高くなる傾向が示された．放射性セシウムを含まないビーズの存在位置が放射能測定値に及ぼす影響は，玄米，玄ソバと大豆において傾向は一致していた．

This paper investigated acrylamide elution from roasted barley grain into mugicha and its formation during roasting of the grain. Mugicha is an infusion of roasted barley grains. Highly water-soluble acrylamide was easily extracted to mugicha from milled roasted barley grains in teabags. On the other hand, the acrylamide concentration in mugicha prepared from loose grain increased with longer simmering and steeping times. During roasting in a drum roaster, the acrylamide concentration of the grain increased as the surface temperature rose, reaching a maximum at 180-240 degrees C. Above this temperature, the acrylamide concentration decreased with continued roasting, exhibiting an inverted 'U'-shaped curve. For most of the samples, the acrylamide concentration showed good correlation with the value of the colour space parameter L*. The dark-coloured roasted barley grains with lower L* values contained lower amounts of acrylamide as a result of deep roasting. The level of asparagine in barley grains was found to be a significant factor related to acrylamide formation in roasted barley products. The data are an important contribution to the mitigation of acrylamide intake from mugicha.

Water absorption in individual white-core and non-white-core grains of rice varieties used in sake brewing was observed during soaking by magnetic resonance imaging (MRI). Water was absorbed faster in white-core grains than in non-white-core grains and was pooled in the core. Moisture distributions were compared using the line profiles of nuclear magnetic resonance signal intensities (SI profiles) generated from magnetic resonance images of grains soaked for 2 h. SI profiles of white-core and non-white-core grains overlapped despite slight differences in the central and intermediate regions of the grains. A white-core-like structure with loosely packed starch granules was found to exist in the endosperm of non-white-core grains. SI profiles of grains polished to 70% of the yield weight of brown rice were similar in shape to those of grains polished to 90% of the yield, but their overall moisture content was higher after the removal of the hydrophobic grain periphery. A varietal difference in the thickness of the intermediate region, which may affect fissuring resistance in the polishing process, was detected in SI profiles. Differences in water absorbability between parents and their offspring were also apparent from their SI profiles. MRI enabled the detection of variety-specific water-absorption properties in grains. (C) 2014 Elsevier Ltd. All rights reserved.

We investigated the presence of acrylamide in roasted barley grains, and assessed the correlation between acrylamide concentration and colour, and also examined acrylamide decrease during storage. Acrylamide concentrations in 45 commercially available roasted barley grains were analysed. The mean and standard deviation were 0.24 and 0.08 mg kg(-1), respectively. The CIE colour parameter a* value had little correlation with acrylamide concentration in roasted barley grains; however, the L* and b* values showed correlations with acrylamide concentration in the grains, yielding a correlation coefficient of 0.42 and 0.40, respectively. Darker-coloured roasted barley grains with lower L* values may contain lower amounts of acrylamide. Although acrylamide concentration decreased by 40% in the grains, and decreased by 36% in the milled grains (teabag form) after 309 days of storage at room temperature a significant difference in the rate of acrylamide decrease was not observed between the grain and teabag forms. The data obtained in this study are of importance to the risk assessment and management of acrylamide exposure in Japan.

Glycosylation of flagellin is known to be involved in filament stabilization, motility, and virulence in Pseudomonas syringae. Here we investigated flagellin glycosylation in other phytopathogenic bacteria. Analyses of deduced amino acid sequences, glycostaining, and molecular masses of purified flagellins revealed that flagellins from all phytopathogenic bacteria investigated were glycosylated. Furthermore, the flagellin in a glycosylation-defective mutant of Xanthomonas campestris pv. campestris (Xcc) had a reduced molecular mass, and motility and virulence of the mutant toward host leaves decreased. These results suggest that flagellin glycosylation is ubiquitous in most phytopathogenic bacteria and that flagellin glycosylation is required for virulence in Xcc. © 2013 The Phytopathological Society of Japan and Springer Japan.

A new 16-membered macrolide named makinolide B (1) was isolated from Streptomyces sp. MK-19. The structure of makinolide B (1) was determined on the basis of 2D NMR experiments involving DQF-COSY, TOCSY, HSQC, and HMBC methods. Application of the paper disk diffusion method to maldnolide B (1) showed weak antibacterial activity against Staphylococcus aureus at the dose of 100 mu g/disk.

Scabichelin and turgichelin, novel tris-hydroxamate siderophores, were isolated from Streptomyces antibioticus NBRC 13838/Streptomyces scabies JCM 7914 and Streptomyces turgidiscabies JCM 10429, respectively. The planar structures of scabichelin and turgichelin were elucidated by mass spectrometry, and 1- and 2-D NMR spectroscopic analyses of their gallium(iii) complexes. The relative and absolute stereochemistry of the metabolites was determined by the modified Marfey's method in conjunction with computational modelling and NOESY NMR analysis of Ga-scabichelin and Ga-turgichelin. Genome sequence analysis of the plant pathogen Streptomyces scabies 87.22 identified a gene cluster containing a gene encoding a nonribosomal peptide synthetase (NRPS) that was predicted to direct the production of a pentapeptide with structural similarities to scabichelin and turgichelin. Comparative LC-MS/MS analyses of iron-deficient culture supernatants from wild type S. scabies 87.22 and a mutant in which the NRPS gene had been disrupted, and scabichelin purified from S. antibioticus, showed that scabichelin is the metabolic product of the cryptic gene cluster, strongly suggesting that it functions as a siderophore. is © 2013 The Royal Society of Chemistry.

Flagellin is a principal component of the flagellum filament. Previously, we reported that the flagellin of Pseudomonas syringae pv. tabaci 6605 (Pta6605) was glycosylated by oligosaccharides composed of two or three L-rhamnosyl (L-Rha) residues and a terminal 4,6-dideoxy-4-(3-hydroxybutanamide)-2-O-methylglucopyranosyl residue. In this study, we characterized the chemical structure of flagellin glycans in P. syringae pathovars glycinea race 4 (Pgl4), phaseolicola 1448A (Pph1448A), tomato DC3000 (PtoDC3000), and syringae B728a (PsyB728a). Flagellin glycans were released by hydrazinolysis, labeled on the reducing ends with 2-aminopyridine (PA), and the PA-labeled oligosaccharides were isolated by high-performance liquid chromatography. The purified PA-labeled glycans were analyzed by mass spectrometry and NMR spectroscopy. The results showed that the glycans on flagellin of Pgl4, PtoDC3000, and Pph1448A were identical to those of Pta6605, which were characterized previously. The flagellin of PsyB728a is O-glycosylated with a novel trisaccharide identified as 2-acetamide-2-deoxy-beta-D-glucopyranosyl-(1 -&gt; 2)-3-O-methyl-alpha-L-rhamnopyranosyl-(1 -&gt; 2)-L-rhamnose. Our data indicate that flagellin glycosylation of P. syringae pathovars has universality with little diversity. (C) 2013 Elsevier Ltd. All rights reserved.

The ability to suppress soil nitrification through the release of nitrification inhibitors from plant roots is termed 'biological nitrification inhibition' (BNI). Here, we aimed at the quantification and characterization of the BNI function in sorghum that includes inhibitor production, their chemical identity, functionality and factors regulating their release. Sorghum was grown in solution culture and root exudate was collected using aerated NH4Cl solutions. A bioluminescence assay using recombinant Nitrosomonas europaea was employed to determine the BNI activity. Activity-guided chromatographic fractionation was used to isolate biological nitrification inhibitors (BNIs). The chemical structure was analyzed using NMR and mass spectrometry; pH-stat systems were deployed to analyze the role of rhizosphere pH on BNIs release. Sorghum roots released two categories of BNIs: hydrophilic- and hydrophobic-BNIs. The release rates for hydrophilic- and hydrophobic- BNIs ranged from 10 to 25 ATU g(-1) root dwt. d(-1). Addition of hydrophilic BNIs (10 ATU g(-1) soil) significantly inhibited soil nitrification (40 % inhibition) during a 30-d incubation test. Two BNI compounds isolated are: sakuranetin (ED80 0.6 mu M; isolated from hydrophilic-BNIs fraction) and sorgoleone (ED80 13.0 mu M; isolated from hydrophobic-BNIs fraction), which inhibited Nitrosomonas by blocking AMO and HAO enzymatic pathways. The BNIs release required the presence of NH (4) (+) in the root environment and the stimulatory effect of NH (4) (+) lasted 24 h. Unlike the hydrophobic-BNIs, the release of hydrophilic-BNIs declined at a rhizosphere pH &gt; 5.0; nearly 80 % of hydrophilic-BNI release was suppressed at pH a parts per thousand yen7.0. The released hydrophilic-BNIs were functionally stable within a pH range of 5.0 to 9.0. Sakuranetin showed a stronger inhibitory activity (ED50 0.2 mu M) than methyl 3-(4-hydroxyphenyl) propionate (MHPP) (ED50 100 mu M) (isolated from hydrophilic-BNIs fraction) in the in vitro culture-bioassay, but the activity was non-functional and ineffective in the soil-assay. There is an urgent need to identify sorghum genetic stocks with high potential to release functional-BNIs for suppressing nitrification and to improve nitrogen use efficiency in sorghum-based production systems.

D-rhamnose (D-Rha) residue is a major component of lipopolysaccharides (LPSs) in strains of the phytopathogen Pseudomonas syringae pathovar glycinea. To investigate the effects of a deficiency in GDP-D-rhamnose biosynthetic genes on LPS structure and pathogenicity, we generated three mutants defective in D-Rha biosynthetic genes, encoding proteins GDP-D-mannose 4,6-dehydratase (GMD), GDP-4-keto-6-deoxy-D-mannose reductase (RMD), and a putative α-D-rhamnosyltransferase (WbpZ) in P. syringae pv. glycinea race 4. The Δgmd, Δrmd, and ΔwbpZ mutants had a reduced O-antigen polysaccharide consisting of D-Rha residues as compared with the wild type (WT). The swarming motility of the Δgmd, Δrmd, and ΔwbpZ mutant strains decreased and hydrophobicity and adhesion ability increased as compared with WT. Although the mutants had truncated O-antigen polysaccharides, and altered surface properties, they showed virulence to soybean, as WT did.

D-rhamnose (D-Rha) residue is a major component of lipopolysaccharides (LPSs) in strains of the phytopathogen Pseudomonas syringae pathovar glycinea. To investigate the effects of a deficiency in GDP-D-rhamnose biosynthetic genes on LPS structure and pathogenicity, we generated three mutants defective in D-Rha biosynthetic genes, encoding proteins GDP-D-mannose 4,6-dehydratase (GMD), GDP-4-keto-6-deoxy-D-mannose reductase (RMD), and a putative alpha-D-rhamnosyltransferase (WbpZ) in P. syringae pv. glyeinea race 4. The Delta gmd, Delta rmd, and Delta wbpZ mutants had a reduced O-antigen polysaccharide consisting of D-Rha residues as compared with the wild type (WT). The swarming motility of the Delta gmd, Delta rmd, and Delta wbpZ mutant strains decreased and hydrophobicity and adhesion ability increased as compared with WT. Although the mutants had truncated O-antigen polysaccharides, and altered surface properties, they showed virulence to soybean, as WT did.

Moisture distribution in individual polished rice grains was observed during soaking by magnetic resonance (MR) imaging, and a nuclear magnetic resonance (NMR) signal intensity profile (SI-profile) was generated from the MR image. The water penetration pattern during soaking roughly showed dissimilar trends between different varieties of japonica and japonica-indica hybrid rice. NMR signal intensity at the completion of water absorption varied within each grain; high at the periphery and the central region and low in the area between the periphery and the central region. High moisture content within the central region is due to loosely packed starch granules. The SI-profile was congruent for grains of the same variety harvested in different regions and years and characterized a grain moisture distribution for each variety. Moisture distribution was compared using SI-profiles for varieties with different amylose contents and new varieties bred for specific end-uses in Japan. The NMR signal intensity, which is related to the moisture content, at the surface of soaked grain was negatively correlated to the grain amylose content. The NMR signal intensities at the surface of soaked grain negatively correlated with the overall hardness of the cooked rice grain as measured by the single-grain low-high compression test. (c) 2012 Elsevier Ltd. All rights reserved.

The T-2 distribution change of boiled dry spaghetti was evaluated by MRI T-2 maps and T-2 profiles, in which T-2 values were plotted against the distance from the surface. Morphological observations of its internal structure were conducted using fluorescence microscopy. The T-2 values monotonically decreased with the increase of the distance from the surface of boiled dry spaghetti, during the earliest stage after boiling. As the holding period increases from 10 to 120 min, the T-2 value decreases at the surface and increases at the spaghetti center. This is possibly owing to moisture redistribution in the boiled dry spaghetti during the holding period. Three slope-change points and four distinct slope regions were observed in the T-2 profile after a 120-min holding period, indicating that the T-2 gradient differed between the four regions after the moisture redistribution process. Differences in the degree of starch granule swelling and disintegration were observed using fluorescence microscopy. Appearance of the different slope regions in the T-2 profile is suggested to be related to regional differences in the degree of gelatinization in boiled dry spaghetti. One of the slope-change points in the T-2 profile was used to estimate the proportion of a less gelatinized region relative to the whole area of the cross-section. The total moisture content of the boiled spaghetti determined this proportion, regardless of the diameter of dry spaghetti before boiling. These findings indicate that monitoring changes in the T-2 profile of boiled dry spaghetti during the holding period is a useful method for evaluating differences in the internal microstructure and the degree of starch gelatinization, which affected the changes in the moisture distribution. (C) 2012 Elsevier Ltd. All rights reserved.

Type IV pilin (PilA) is a major constituent of pilus and is required for bacterial biofilm formation, surface motility and virulence. It is known that mature PilA is produced by cleavage of the short leader sequence of the pilin precursor, followed by methylation of N-terminal phenylalanine. The molecular mass of the PilA mature protein from the tobacco bacterial pathogen Pseudomonas syringae pv. tabaci 6605 (Pta 6605) has been predicted to be 12 329 Da from its deduced amino acid sequence. Previously, we have detected PilA as an approximately 13-kDa protein by immunoblot analysis with anti-PilA-specific antibody. In addition, we found the putative oligosaccharide-transferase gene tfpO downstream of pilA. These findings suggest that PilA in Pta 6605 is glycosylated. The defective mutant of tfpO (?tfpO) shows reductions in pilin molecular mass, surface motility and virulence towards host tobacco plants. Thus, pilin glycan plays important roles in bacterial motility and virulence. The genetic region around pilA was compared among P. syringae pathovars. The tfpO gene exists in some strains of pathovars tabaci, syringae, lachrymans, mori, actinidiae, maculicola and P. savastanoi pv. savastanoi. However, some strains of pathovars tabaci, syringae, glycinea, tomato, aesculi and oryzae do not possess tfpO, and the existence of tfpO is independent of the classification of pathovars/strains in P. syringae. Interestingly, the PilA amino acid sequences in tfpO-possessing strains show higher homology with each other than with tfpO-nonpossessing strains. These results suggest that tfpO and pilA might co-evolve in certain specific bacterial strains.

Acrylamide levels in commercially available potato chips in Japan were monitored between August 2006 and June 2010 using the xanthydrol derivative gas chromatography-mass spectrometry (GC-MS) method. Seasonal and annual changes in acrylamide concentrations were determined. Nationwide bimonthly sampling of potato chips was carried out using a four-level design, and seasonal variations were detected in which the minimum acrylamide concentration was observed in August, and the maximum between February and June. Seasonal variations became less apparent after August 2008 as a result of annual effects and/or mitigation measures taken by the potato chip producers. Sampling uncertainties were separated into time-to-time, city-to-city, and lot-to-lot variation, and the largest variation was shown to be lot-to-lot including bag-to-bag.

Previously we revealed that flagellin proteins in Pseudomonas syringae pv. tabaci 6605 (Pta 6605) were glycosylated with a trisaccharide, modified viosamine (mVio)-rhamnose-rhamnose and that glycosylation was required for virulence. We further identified some glycosylation-related genes, including vioA, vioB, vioT, fgt1, and fgt2. In this study, we newly identified vioR and vioM in a so-called viosamine island as biosynthetic genes for glycosylation of mVio in Pta 6605 by the mass spectrometry (MS) of flagellin glycan in the respective mutants. Furthermore, characterization of the mVio-related genes and MS analyses of flagellin glycans in other pathovars of P. syringae revealed that mVio-related genes were essential for mVio biosynthesis in flagellin glycans, and that P. syringae pv. syringae B728a, which does not possess a viosamine island, has a different structure of glycan in its flagellin protein.

Flavonoids accumulated in proanthocyanidin-free near-isOgenic lines iso ant.13, iso ant 17, and iso ant 22 of IVishinohoshi, developed by backcross breeding using a leading cultivar, Nishincihoslii, as a recurrent parent and a proanthocyanidinfree mutant as a nonrecurrent parent in Japan, were examined. A new flavanone, (2RS)-dihydrotricin 7-043-n-glucopyranoside (1), known flavanones (2RS)-dihydrotricin (2) and (2RS)-homoeriodictyol (3),_an,41&lt;noWn.flavones chrysoerio17-0-[a-L-rhamnopyranosyl(1-6)13-D-glucopyranoside] (4), chrysoeriol 7-0-13-D-glucopyranoside_(5)4Fitn (6), and chryioeriol (7) were isolated from iso ant 17 of Nishinohoshi. The structures and stereochernistries of the isirilateii.flaVdUoi& (14-7) were elucidated on the basis of spectroscopic analyses The concentrations of the isolated flavonoids (1.-7-).1tis6.200 13, isd.ant.,17; and iso ant 22 of Nishinohoshi were similar to each other, whereas the flavonoids 1-5 and 7 were not detectaidNishinohoshi,,an Old Japanese cultivar, Amaginijo, and North American cultivar Harrington. The concentration of tricin (6) in N;AShinolioshi was a half those in iso ant 13, iso ant 17, and iso ant 22 of Nishinohoshi. Except for iso ant 13, iso ant 17, and iso ant. 22&apos;61-N4hinohoshi,&apos;`the&apos; concentration of tricin (6) was highest in Nishinohoshi, followed by Amaginijo and Harrington. Thus,.44eiti:,(6), its precursor dihydrotricin (2), and its glucopyranosicle, dihydrotricin 7-0-fi-n-glucopyranoside (1), as well as chryidei7ol(7) and homoeriodictyol (3) were accumulated in iso ant 13, iso ant 17, and iso ant 22 of Nishinohoshi probably by blockingrafqi.step of flavanone 3-hydroxylase in the procyanidin biogenetic pathway, resulting in enhancement of the alternative biogenetic pathway.

A new siderophore named tsukubachelin was isolated from an iron-deficient culture medium of newly isolated strain Streptomyces sp. TM-34. The chemical structure of tsukubachelin was established by the interpretation of 2D NMR and TOF-Mass spectroscopic data. The structure of tsukubachelin consists of six amino acid residues, including three serine, and one each of N-alpha-methyl-N-delta-hydroxy-N-delta-formylornithine, N-alpha-methyl-N-delta-hydroxyornithine, and cyclic N-hydroxyornithine. Because the structurally related siderophore, desferri-foroximithine, was reported to have potent angiotensin-converting enzyme inhibition activity, the inhibitory activity of desferri-tsukubachelin and desferri-foroximithine were tested for structure-activity comparison. Desferri-tsukubachelin showed 14 times more potent inhibitory activity than desferri-foroximithine. This result indicates that desferri-tsukubachelin may become a promising agent for angiotensin-converting enzyme inhibition.

日本人の主食である炊飯米からのアクリルアミド摂取寄与を推定するために，炊飯米に関して臭素化誘導体化GC-MS法による低濃度での定量分析法を確立し，アクリルアミドの測定を行った．本分析法の玄米おけるLOQは0.20 μg/kg，LODは0.09 μg/kg，発芽玄米では，LOQは0.17 μg/kg，LODは0.07 μg/kg，精白米では，0.14 μg/kg，LODは0.06 μg/kgであった．2種類の家庭用炊飯装置で炊飯を行った結果，米に生じたアクリルアミドの濃度は，発芽玄米，玄米，精白米の順であった．IH真空圧力炊き炊飯器の1機種を用いた炊飯ではいずれの米の場合も，電子ジャー炊飯器の1機種を用いた炊飯よりもアクリルアミド濃度は低く，業務用炊飯装置の1機種による炊飯ではさらにアクリルアミド濃度は低かった．この炊飯器の違いによるアクリルアミド濃度の差は，炊飯時の温度履歴の違いと高温になる鍋肌の材質の違いによると考えられた．本測定結果を日本人の炊飯米の摂取量と合わせて考えると，他の食品を含めたアクリルアミドの摂取量全体に対して，炊飯した精白米からのアクリルアミド摂取の寄与は小さいことが確認された．玄米および発芽玄米についても，IH真空圧力炊き炊飯器や業務用炊飯器で炊飯すれば，アクリルアミド摂取に対する寄与率は小さいが，焦げを生じさせるとその寄与はアクリルアミドの摂取源の一つとして無視できないものとなり得る．

A bromo-derivatization gas chromatography mass spectrometry (GC-MS) method for quantification of acrylamide in cooked rice was established for the estimation of acrylamide intake from a staple food in Japan. Limit of quantification (LOQ) and limit of detection (LOD) of acrylamide were, respectively, 0.20 and 0.09 mu g/kg for cooked brown rice. 0.17 and 0.07 mu g/kg for cooked germinated brown rice, and 0.14 and 0.06 mu g/kg for cooked polished rice. The rank order of acrylamide concentration in rice, cooked with two types of home-use rice cooker, was germinated brown rice &gt; brown rice &gt; polished rice. Of the home-use rice cookers, less acrylamide was formed with the newer multifunctional type. Less acrylamide was formed using a professional use cooker than with the two cookers for home use. These differences might be derived from differences in temperature history and/or contact of rice grains 1:0 the high temperature bottom surface of the cookers. Considered in the context of the amount of cooked rice consumed in Japan (337.7 g/day on average). the acrylamide in cooked polished rice can be regarded as a minor factor in the total intake of acrylamide of the Japanese. Acrylamide formation in brown rice and germinated brown rice also occurs at vary low levels, unless they are over-heated to the point of burnt rice. (Received May 23. 2011 Accepted Aug. 4. 2011)

Three new nitrogen-containing heterocyclic alkaloids, oryzamutaic acids H-J (1-3), were isolated from the endosperm (polished rice) of an Oryza sativa mutant. The structures and relative stereochemistries of 1-3 were elucidated on the basis of spectroscopic analyses. The presence of three carbons, each bound to a carboxyl group and a nitrogen atom in the structure of 1, suggests that oryzamutaic acids H-J (1-3) are generated from three molecules of a single amino acid. (C) 2010 Elsevier Ltd. All rights reserved.

Xylo-oligosaccharides containing 4-O-methyl glucuronic acid (MeGlcA) residues attached to two adjacent xylosyl residues and those with a single MeGlcA residue were isolated from partial acid hydrolyzates of the arabinoglucuronoxylans (AGX) from Japanese cedar (Sugi, Cryptomaria japonica) and Hinoki cypress (Chamaecyparis obtusa). The ratio of xylo-oligosaccharides with two MeGlcA residues and those with a single MeGlcA residue was about 1:3 for both Sugi and Hinoki. Four xylo-oligosaccharides with two MeGlcA residues were labeled at their reducing end with 2-aminobenzamide (2AB). The 2AB-labeled oligosaccharides (1-4) were structurally characterized using normal-phase liquid chromatography, electrospray-ionization mass spectrometry (ESI-MS), and nuclear magnetic resonance (NMR) spectroscopy. The signals in the (1)H and (13)C NMR spectra of the 2AB-labeled oligosaccharides were fully assigned using one- and two-dimensional NMR spectroscopy. (C) 2010 Elsevier Ltd. All rights reserved.

The effects of global warming have been observed in several crops as changes in temperature-dependent processes, such as dormancy in perennial fruit trees. We exposed potted Japanese pear 'Housui' plants to 600 chilling hours (CH) below 7.2 degrees C, which is below the theoretical requirement. Such low chilling accumulation was initiated at different times (three treatments) and carried out during four consecutive seasons in order to observe the influence of these factors on the incidence and severity of floral primordia necrosis, water dynamics, phenological, and morphological changes during dormancy in lateral mixed buds, which is comprised of vegetative and reproductive primordia, obtained from the current season's shoots. The submitted amount of chilling temperatures brought about the release of dormancy stage, regardless of seasonal variations in the duration to accumulate 600 CH, but caused a remarkable increase of floral primordia necrosis and a great increase in the number of floral primordia as a consequence of the development of new inflorescences; however, these morphological changes did not increased number of opened flowers because of the progression of floral primordia necrosis. Consecutive seasons of mild winter conditions anticipated the incidence of floral primordia necrosis. The results obtained from magnetic resonance imaging in the buds of plants subjected to low chilling accumulation showed low water mobility and water content especially in scales compared to plants grown under natural conditions. In contrast, increased water mobility and relative content were observed in specific portions of the bud base in treated buds, which was more accentuated in the mixed buds of plants grown for several seasons under mild winter conditions. Moreover, abnormal functional water movement inside dormant mixed buds might result in the necrosis of floral primordia, giving way to the development of new inflorescences.

Oryzamutaic acids B-G (1-6), structurally unique nitrogen-containing heterocyclic alkaloids, were isolated from the endosperm (polished rice) of an Oryza sativa mutant. The structures and relative stereochemistries of 1-6 were elucidated on the basis of spectroscopic and single-crystal X-ray diffraction analyses. (C) 2009 Elsevier Ltd. All rights reserved.

Flagellar motility and its glycosylation are indispensable for the virulence of Pseudomonas syringae pv. tabaci 6605. Six serine residues of the flagellin protein at positions 143, 164, 176, 183, 193 and 201 are glycosylated, and the glycan structure at 201 was determined to consist of a trisaccharide of two L-rhamnosyl residues and a modified 4-amino-4,6-dideoxyglucosyl (viosamine) residue. To investigate the glycan structures attached to the other serine residues and to identify the glycans important for virulence, Ser/Ala-substituted mutants were generated. Six mutant strains that each retained a single glycosylated serine residue were generated by replacing five of the six serine residues with alanine residues. MALDI-TOF mass analysis of flagellin proteins revealed that the major component of each glycan was a trisaccharide basically similar to that at position 201, but with heterogeneity in glycoform distribution. Swarming motility and amounts of acylhomoserine lactones (AHLs) as quorum-sensing signal molecules were significantly reduced, especially in the S143-5S/A, S164-5S/A and S201-5S/A mutants, whereas tolerance to antibiotics was increased in these three mutants. All the mutants showed lower ability to cause disease on host tobacco plants. These results supported our previous finding that glycosylation of the most externally located sites on the surface of the flagellin molecule, such as S176 and S183, is required for virulence in P. syringae pv. tabaci 6605. Furthermore, it is speculated that flagellum-dependent motility might be correlated with quorum sensing and antibiotic resistance.

Glycosylation of flagellin contributes to swimming and swarming motilities, adhesion ability, and consequently virulence in Pseudomonas syringae pv. tabaci 6605. Glycans attached to six serine residues are located in the central region of the flagellin polypeptide. The glycan structure at position Ser 201 was recently revealed to consist of two l-rhamnoses and one modified 4-amino-4,6-dideoxyglucose (viosamine). To clarify the mechanisms for glycosylation of modified viosamine, genes encoding dTDP-viosamine aminotransferase (vioA), dTDP-viosamine acetyltransferase (vioB), and viosamine-derivative transferase (vioT) were isolated and defective mutants were generated. MALDI-TOF-MS analysis of a lysyl endopeptidase-digested peptide including all six glycosylation sites from each flagellin indicated that the molecular masses of the three flagellin mutants were reduced with highly heterogeneous patterns at regular intervals of 146 Da in the mass range from m/z 13,819 to 15,732. The data indicated that the glycopeptides obtained from mutants had glycans consisting only of deoxyhexose instead of the flagellin glycans including the viosamine derivatives determined previously. The motility and virulence on host tobacco leaves were strongly impaired in the Delta vioA mutant and were weakly reduced in the Delta vioB and Delta vioT mutant strains. These results suggest that the genes vioA, vioB, and vioT are essential for glycosylation of flagellin, and accordingly are required for bacterial virulence.

ダイズ播種時の出芽不良の大きな要因である吸水障害は，急激な吸水による子葉とその維管束の断裂に起因することがMRIでの観察で示された。この吸水障害は可塑性に乏しい過度に乾燥した種子ほど顕著であり，その回避には種子全体の水分を15％w.b.前後に保つだけでなく，種子表面と内部の水分差を2％w.b.以内とすることが不可欠であった。そのためには，調湿方法に依らず，種子全体を15％w.b.前後に調湿した後，さらに種子水分均一化のために調湿処置期間を含めて計3～4日経る必要があった。また通常の梅雨期の土壌水分に乾燥種子を播種すると吸水障害が多発したので，調湿種子の利用が吸水障害の回避に有効と考えられる。

The flagellin of Pseudomonas syringae pv. tabaci is a glycoprotein that contains O-linked oligosaccharides composed of rhamnosyl and 4,6-dideoxy-4-(3-hydroxybutanamido)-2-O-methylglucosyl residues. These O-linked glycans are released by hydrazinolysis and then labeled at their reducing ends with 2-aminopyridine (PA). A PA-labeled trisaccharide and a PA-labeled tetrasaccharide are isolated by normal-phase high-performance liquid chromatography. These oligosaccharides are structurally characterized using mass spectrometry and NMR spectroscopy. Our data show that P. syringae pv. tabaci flagellin is glycosylated with a tetrasaccharide, 4,6-dideoxy-4-(3-hydroxybutanamido)-2-O-methyl-Glcp-(1 -&gt; 3)-alpha-L-Rhap-(1 -&gt; 2)-alpha-L-Rhap-(1 -&gt; 2)-alpha-L-Rha-(1 -&gt;, as well a trisaccharide, 4,6-dideoxy-4-(3-hydroxybutanamido)-2-O-methyl-Glcp-(1 -&gt; 3)-alpha-L-Rhap-(1 -&gt; 2)-alpha-L-Rha-(1 -&gt;,which was identified in a previous study. (C) 2009 Elsevier Ltd. All rights reserved.

Nitrification, a key process in the global nitrogen cycle that generates nitrate through microbial activity, may enhance losses of fertilizer nitrogen by leaching and denitrification. Certain plants can suppress soil-nitrification by releasing inhibitors from roots, a phenomenon termed biological nitrification inhibition (BNI). Here, we report the discovery of an effective nitrification inhibitor in the root-exudates of the tropical forage grass Brachiaria humidicola (Rendle) Schweick. Named "brachialactone,&apos;&apos; this inhibitor is a recently discovered cyclic diterpene with a unique 5-8-5-membered ring system and a gamma-lactone ring. It contributed 60-90% of the inhibitory activity released from the roots of this tropical grass. Unlike nitrapyrin (a synthetic nitrification inhibitor), which affects only the ammonia monooxygenase (AMO) pathway, brachialactone appears to block both AMO and hydroxylamine oxidoreductase enzymatic pathways in Nitrosomonas. Release of this inhibitor is a regulated plant function, triggered and sustained by the availability of ammonium (NH(4)(+)) in the root environment. Brachialactone release is restricted to those roots that are directly exposed to NH(4)(+). Within 3 years of establishment, Brachiaria pastures have suppressed soil nitrifier populations (determined as amoA genes; ammonia-oxidizing bacteria and ammonia-oxidizing archaea), along with nitrification and nitrous oxide emissions. These findings provide direct evidence for the existence and active regulation of a nitrification inhibitor (or inhibitors) release from tropical pasture root systems. Exploiting the BNI function could become a powerful strategy toward the development of low-nitrifying agronomic systems, benefiting both agriculture and the environment.

High-temperature stress during grain ripening facilitates the formation of chalky grains through loose packing of amyloplasts. In the present study, the changes in water distribution in the developing caryopses by high-temperature stress were investigated by magnetic resonance imaging. Milky-white and white-cored types of chalky grains, which had chalkiness around the centre of the endosperm, were formed in a high percentage in a high-temperature condition by the middle dry-matter accumulating stage. Magnetic resonance images of the early stage caryopses in the high-temperature condition showed a lower water content around the centre of the endosperm, where the disorganized development of amyloplasts was observed by scanning electron microscopy. Transcripts for alpha-amylase were, however, not detected there in the early and middle stage, indicating that starch degradation by alpha-amylase was not the cause of the formation of these types of chalky grains. In the middle stage, water content in the central chalky part became higher than in the lateral translucent part. Loose packing of amyloplasts in the chalky part may allow pooling of water in the free spaces leading to the higher water content after the middle stage. Together with the results, the physiological mechanism for the formation of white-cored and milky-white grains that occurred by high-temperature stress was discussed. (C) 2009 Elsevier Ltd. All rights reserved.

Soft electrons (low-energy electrons) have been reported to effectively disinfest grains contaminated with stored-product insects. In this study, brown rice grains infested with different ages of the maize weevil, Sitophilus zeamais Motschulsky, were exposed to soft electrons. Soft electrons at an acceleration voltage of 170 kV effectively inactivated eggs, old larvae and pupae of the maize weevil, but could not completely inactivate young larvae. The locations of young larvae in rice grains were specified by magnetic resonance microimaging. Most of the larvae resided at the periphery of the grains while only a few at the center, which were assumed to get out of inactivation. This indicated that soft electrons with low penetration capacity could reach the most of weevil larvae in grains. Combination of soft-electron treatment and short time-low-close phosphine fumigation achieved high mortality rate of S. zeamais. (C) 2009 Elsevier Ltd. All rights reserved.

We show that selection of drug-resistant bacterial mutants allows the discovery of antibacterial compounds. Mutant strains of a soil-isolated Streptomyces species that does not produce antibacterials synthesize a previously unknown class of antibacterial, which we name piperidamycin. Overall, 6% of non-Streptomyces actinomycetes species and 43% of Streptomyces species that do not produce antibacterials are activated to produce them. The antibacterial-producing mutants all carried mutations in RNA polymerase and/or the ribosomal protein S12.

Magnetic resonance imaging (MRI) was employed to observe water diffusion within two kinds of buckwheat noodles (marunuki, sarashina) and one kind of wheat noodle during boiling and holding. The apparent diffusion coefficients for water were statistically estimated with Fick&apos;s second law using a rectangular cylinder model, and the changes in moisture distribution in buckwheat and wheat noodles were compared quantitatively. Apparent diffusion coefficients of water in noodles during boiling were 4 to 7 x 10(-6) cm(2)/sec. The diffusion coefficients of water in buckwheat noodles during boiling were higher than those in wheat noodles. For each noodle, the diffusion coefficient during holding after boiling was 2 to 3 x 10(-7) cm(2)/sec and constant through the holding time, from 30 to 120 min. The diffusion coefficients in buckwheat noodles during holding were lower than those in wheat noodles. These results show that, as compared with wheat noodles, buckwheat noodles cooked more rapidly and lost favorable texture during holding.