A selective medium (designated as NSVC-In medium) was developed to isolate of Erwinia , the causal agent of bacterial palea browning of rice. Medium NSVC-In contains per 1000ml of distilled water: 10g inositol, 10g peptone, 50g NaCl, 100mg vancomycin, 100mg cycloheximide, and 15g agar. The medium is adjusted to pH 6.8 with NaOH before autoclaving. Plant pathogenic E. grew well on this medium to develop characteristic colonies, but the growth of nonpathogenic E. and Erwinia herbicola was inhibited. Plating efficiency of this medium for pathogenic E. was the same as that of nutrient agar medium. Pathogenic E. could be selectively detected from dead leaves of rice plants.

抄録全体を表示

In this study, we investigated hypolipidemic mechanisms of the ethanolic extract of

Ananas

comosus L. leaves (AC) in mice and then determined its activities in related enzymes. The results showed that AC (0.40 g/kg) significantly inhibited the increase in serum triglycerides by 40% in fructose-fed mice. In mice induced by alloxan and high-fat diets, serum total cholesterol remained at a high level (180 – 220 mg/dl) within 7 days of removing high-fat diets but reached normal level (120 – 140 mg/dl) after AC (0.40 g/kg per day) treatment. Also, AC (0.40 and 0.80 g/kg) significantly inhibited serum lipids from the increase in Triton WR-1339-induced hyperlipidemic mice. AC (0.01 – 100 μg/ml) selectively activated lipoprotein lipase (LPL) activity by 200% – 400% and significantly inhibited 3-hydroxyl-methyl glutaryl coenzyme A (HMGCoA) reductase activity by 20% – 49% in vitro. Furthermore, 2 months of fenofibrate (0.20 g/kg) administration particularly increased mice liver weights (0.0760 ± 0.0110 g/g) while AC (0.40 g/kg) had no effect (0.0403 ± 0.0047). Taken together, these results suggest that AC will be a new potential natural product for the treatment of hyperlipidemia that exerts its actions through mechanisms of inhibiting HMGCoA reductase and activating LPL activities. Its action mechanisms differentiate from those with fibrates but may be partly similar to those with statins. It is hopeful that AC may serve as the adjuvant for fibrates.

抄録全体を表示

  The ice-nucleating bacterium Pantoea KUIN-3 accumulated glucose in cells following a shift in temperature (10°C) from the optimum growth temperature (30°C). This accumulation might be caused by the activation of glucose-6-phosphatase. Although this strain after culturing at 30°C was harmed by freezing, the cryotolerance of this strain was reached about 80% after cold acclimation at 10°C.

抄録全体を表示

1．スウィーティオパイナップルはレギュラーパイナップルに比べ豊かな香りが特徴であるが，香気成分量的にも顕著に多いことが確認された．また，上，中，下部の香気成分量に大きな違いがなく，最も少ない上部においても，レギュラーよりも香気成分量が多いことがわかった．
2．フラネオール含量はいずれのパイナップルにおいても高い含有量を示すが，レギュラーでは，フラネオールの含有量が，突出しているのが特徴であるのに対し，スウィーティオでは，フラネオールの他に，3-（メチルチオ）プロパン酸メチル，メシフラン，ヘキサン酸メチル，4-ヘキサノライド，2-メチルブタン酸メチルおよびヘキサン酸エチルの含有量が高く，全体の成分組成のバランスが両パイナップル香気の違いに関与していると考察された．
3．AEDA法およびodor unitによりスウィーティオパイナップルの香気寄与成分を抽出すると，量的な主成分であったフラノン類，含S化合物などに加えて短鎖のエステル類である2-メチルブタン酸メチルと2-メチルブタン酸エチルが重要成分として抽出された．
4．2-メチルブタン酸メチルと2-メチルブタン酸エチルの立体配置について検討した結果，スウィーティオパイナップルでは，それぞれ97.4％ eeおよび100.0％ ee, レギュラーパイナップルでは99.0％ eeおよび100.0％ eeで（S）-体を主成分としていることを確認した．
5．高いodor unitを示した2-メチルブタン酸メチルと2-メチルブタン酸エチルについて，ラセミ体を用いてであるがレギュラージュースへの添加実験を行い，官能評価を行った結果，この2種類のエステルを添加することにより，“広がりのある”，“さわやかな”および“果実様の”香りが強められ，スウィーティオパイナップルの香りに類似することが確認され，重要成分であることが分かった．

抄録全体を表示

1999年, 山形県酒田市で加温栽培されているフリージアに, 下位葉が褐変する症状が発生した。罹病部からは首腐病菌Burkholderia gzadioli pv. gzadioliが分離され, フリージア首腐病と診断したが, 同時にこれまでに記載が無かったErwinia も分離され, 接種試験により本菌の病原性が確認された。今回の症状は分離頻度から主にErwinia によるものと思われたが, 症状は前者に比べて軽く, 球根予冷中の節水管理により被害が軽減できることが明らかになった。

抄録全体を表示

Effects of potassium cyanide (KCN), salicylhydroxamic acid (SHAM), and oxygen concentrations on mitochondrial respiration were investigated in purified mitochondria of a typical phosphoenolpyruvate carboxykinase (PCK) crassulacean acid metabolism (CAM) plant

Ananas

comosus (pineapple) and a typical malic enzyme (ME)-CAM plant Kalanchoë daigremontiana. Mitochondria of A. comosus oxidized succinate and NADH faster than that of K. daigremontiana. Succinate and NADH oxidations in mitochondria of both species were partially inhibited by KCN and SHAM, indicating that these oxidations were connected to cytochrome and alternative pathways in their electron transport chain (ETC). NADH oxidation was more sensitive to KCN than succinate oxidation, suggesting that the ETC from NADH oxidation was less connected to the alternative pathway than that from succinate in mitochondria of both species. Concurrent oxidation of succinate and NADH resulted in much higher rates of cytochrome and alternative respirations than each individual oxidation alone in both species. NADH oxidation in A. comosus mitochondria was more connected to the cytochrome pathway, so A. comosus could produce much more ATP than K. daigremontiana. This capacity might be one of the fitting mechanisms of A. comosus to produce a sufficient amount of ATP for cytosolic PCK in the daytime. In addition, the reduction of oxygen concentrations decreased not only the cytochrome respiration, but also the alternative respiration on succinate oxidation in mitochondria of both species, and the decrease was greater in K. daigremontiana than in A. comosus.

抄録全体を表示

Simple sequence repeat (SSR) markers provide a reliable tool for the identification of accessions and the construction of genetic linkage maps because of their co-dominant inheritance. In the present study, we developed new SSR markers with next-generation sequencing using the Roche 454 GS FLX+ platform. Five hundred SSR primer sets were tested for the genetic identification of pineapple, including 100 each for the di-, tri-, tetra-, penta-, and hexa-nucleotide motif SSRs. In total, 160 SSR markers successfully amplified fragments and exhibited polymorphism among accessions. The SSR markers revealed the number of alleles per locus (ranging from 2 to 13), the expected heterozygosity (ranging from 0.041 to 0.823), and the observed heterozygosity (ranging from 0 to 0.875). A total of 117 SSR markers with tri- or greater nucleotide motifs were shown to be effective at facilitating accurate genotyping. Using the SSR markers, 25 accessions were distinguished genetically, with the exception of accessions ‘MD-2’ and ‘Yonekura’. The developed SSR markers could facilitate the establishment of efficient and accurate genetic identification systems and the construction of genetic linkage maps in the future.

抄録全体を表示

The ice nucleation-active protein of Erwinia IN-10 (inaA protein) was over-expressed as inclusion bodies in Escherichia coli in a yield of 15.3mg of inaA protein from 60mg of bacterial cells on a dry-matter basis. The inaA protein was purified from the inclusion bodies by solubilization with detergents to obtain a protein preparation free from sugar and lipid. This preparation had a distinct ice nucleation activity, indicating that the inaA protein per se is able to act as a nucleus.

抄録全体を表示

チャ芽に居住する氷核活性細菌Xanthomonas campestrisとErwinia の生態および霜害との関係を研究するため選択培地を作成した。X. campestrisの分離培地(略称SGNC)の組成はNH₄H₂PO₄ 1g, MgSO₄・7HO₂ 0.2g, KCl 0.2g,グリコゲン10g,ノボビオシン100mg,シクロヘキシミド100mg,寒天15g,蒸溜水1,000ml, pH 6.8である。またE. の分離培地(略称NSVC)は,普通寒天培地(酵母エキス5g,ペプトン10g,寒天15g,蒸溜水1,000ml, pH 6.8)にNaCl 50g,バンコマイシン100mgおよびシクロヘキシミド100mgを加えた。両選択培地の平板効率は普通寒天培地のそれと同じであった。X. campestrisはSGNC培地上で3∼4日目に,またE. はNSVC培地上で2日目に集落を形成した。チャ芽に居住する一般細菌は種類が比較的少ないため,両培地の選択性はきわめて高く,氷核活性細菌の生態を定量的に解明することが可能となった。しかし降雨が数日続くとNSVC培地上に生育する一種の細菌の増殖がみられたが,降雨が止むと24時間以内に消失した。NSVC培地はイネ内穎褐変病の病原細菌にも適用できる。

抄録全体を表示

Factors affecting the development of the ice nucleation (IN) activity of Erwinia IN-10 were examined, using the degree of supercooling (DS) as a parameter. An aqueous suspension of the bacterial cells or the outer membrane fraction showed two particular DS values, i.e., near 0°C and 3°C. The development of the DS of 0°C required two conditions: a high cell (or membrane) concentration and the presence of a water/glass interface in the system. Sugars inhibited the development of this type of supercooling. The IN activity was stable in the pH range of 5 to 10. On the basis of these data, a possible mechanism for the IN activity development was proposed. The application of the IN activity of the cells to the freeze-drying of high salt containing foods was attempted. It led to a shortening of their freezing times and efficient formation of powdered products.

抄録全体を表示

Detailed karyotype studies have been carried out on 15 different species and varieties belonging to 7 genera of Bromeliaceae, viz. , Bilbergia, Caraguata, Cryptanthus, Dyckia, Neoregelia and Pitcairnia.
Although gross homogeneity in the karyotype among the members of the 7 genera is noticed, yet a critical analysis shows that each species and variety is characterised by the distinctive karyotype of its own, particularly in nature of secondary constriction-so structural alteration of chromosomes has been the prime factor in evolution within the family.
Out of the 4 tribes within this family, in Tillandsieae, the prevalent chromosome series is 8 or 16; in Bromelieae it is 9, 18 and 25 and in Pitcairnieae it is 25. It has been suggested that 8 represents the basic set for this family from which other numbers might have been derived. On the basis of past report and present investigations a rearrangement of different tribes is suggested-Tillandsieae with its basic set of 8 should represent primitive whereas Pitcairnieae with a series of 25 forms the present climax of evolution. The intermediate stages are possibly represented by Bromelieae some of which are common to Tillandsieae and others with Pitcairnieae.

抄録全体を表示

The pineapple (

comosus (L.) Merr.) is an economically important tropical fruit crop. In this study, we performed quantitative trait locus (QTL) analysis using 168 individuals of the F₁ population of ‘Yugafu’ × ‘Yonekura’ for 15 traits: leaf color (L*, a*, b*), harvest day, crown number, slip number, stem shoot number, sucker number, fruit weight, fruit height, fruit diameter, fruit shell color, soluble solid content, acidity, and ascorbic acid content. The constructed single-nucleotide polymorphism (SNP)-based genetic linkage map consisted of a total genetic distance of 2,595 cM with 3,123 loci, including 22,330 SNPs across 25 chromosomes. QTL analysis detected 13 QTLs for 9 traits: leaf color a*, harvest day, fruit weight, fruit height, fruit diameter, fruit shell color, soluble solid content, acidity, and ascorbic acid content. The causative gene for each QTL was predicted with two genes identified as candidate genes. The AcCCD4 gene on Aco3.3C08 was the predicted causative gene for the shell color QTL, which negatively controls shell color by carotenoid degradation. The Myb domain protein-encoding gene on Aco3.3C02 was the predicted causative gene for shell color and leaf color a* QTL, which positively regulates anthocyanin accumulation. The QTL and gene information provided here contributes to future marker-assisted selection for fruit quality.

抄録全体を表示

The chromosome number of 25 Bromeliaceae species from the genera Dyckia, Vriesea, Aechmea, , Billbergia, Nidularium, Neoregelia, Neoglaziovia, Orthophytum, Portea, Quesnelia and Wittrockia were assessed. All are diploid 2n=50, except for Orthophytum albopictum and Neoglaziovia variegata, both tetraploids, 2n=100. The chromosome counts are the first report for 19 of the 25 species evaluated. All chromosome counts reinforce x=25 as the basic number for the family.

抄録全体を表示

We propose a new process for freeze texturing using Erwinia cells as heterogeneous ice nuclei. The bacterial cells, when added to isotropic aqueous dispersions or hydrogels of proteins and polysaccharides, converted the bulk water into directional ice crystals at a subzero temperature of not lower than -5°C, with formation of anisotropically textured products. Raw egg white, bovine blood, soybean curd, milk curd, aqueous dispersions or slurries of soybean protein isolate, hydrogel of agar, corn starch paste, and hydrogels of glucomannan and calcium-bridged glucomannan were used as materials to be textured. These were each mixed with a small mass of the bacterial cells and slowly cooled to -5°C in an air bath. The frozen materials were vacuum-dried before setting the resulting textures by steaming for 2min at 1 atm if necessary, forming flake-like textures. Slicing the textured products at right angles to the lamellas of the flakes gave fibrous products.

抄録全体を表示

前年、我々は群馬県、長野県、及び山梨県の桑園における降霜直前の氷核活性細菌の分布調査を行ったところ、1995年のつくば市周辺の分布傾向とは異なっていたので、さらに栃木県那須地方5ケ所、福島県阿武隈山系11ケ所、及び埼玉県秩父地方9ケ所における氷核活性細菌の分布について同様の調査を行った。2001年10月∼11月に桑園または廃桑園からクワ葉を採取し、平板希釈法により細菌を分離したところ、Er. herbicola群細菌は24地点から、Ps. syringaeは17地点から分離された。LB平板培地で培養したこれらの細菌を、それぞれ1mlの滅菌蒸留水に懸濁し、-5℃、30分で凍結するか否かによって氷核活性能の有無を判定した。その結果、氷核活性能を有するEr. herbicola群細菌(Er. 他)が桑葉より新たに9株分離され、食害していたクワノメイガからも5株分離された。一方、Ps. syringaeは分離された株のほぼ100%が氷核活性能を有しているという興味深い結果が得られた。さらに、これら新たに分離されたEr. herbicola群細菌の氷核活性遺伝子等の解析結果も報告する予定である。

抄録全体を表示