In order to reduce excessive nitrate ion concentrations in vegetables, which may be one of the causes of high blood levels of methemoglobin, the effect of organic fertilizer on yield in hydroponics and the nitrate ion concentration in Japanese hornwort cultivated using the deep-flow technique was evaluated. To investigate seasonal variability, one series of experiments was conducted in three seasons, namely, spring, summer, and autumn. The nitrate ion concentration in Japanese hornwort decreased with the increasing proportion of organic fertilizer to total fertilizer applied; Japanese hornwort plants grown in culture medium containing both organic and chemical fertilizers were able to reduce the nitrate concentration compared with those grown in culture medium containing only chemical fertilizer. In spring and autumn, the nitrate concentration of Japanese hornwort grown in culture medium containing only organic fertilizer was the lowest, although plant height was the lowest. Additionally, when using hydroponics with Japanese hornwort cultured in medium containing only organic fertilizer, it was necessary to lower the temperature of the hydroponic solution to below25℃. These results suggest that a reduction in nitrate ion concentration, whilst maintaining the yield of hydroponically grown plants, is possible in Japanese hornwort when chemical fertilizer is used together with organic fertilizer.

　Immature papaya (green papaya) is used as a vegetable in Okinawa, Japan. However, there is little information regarding its storage. We investigated the relationship between storage temperature and the respiratory rate of vegetable papaya, and estimated a suitable storage temperature. Next, we examined the effect of storage conditions on the quality of papaya fruit. Chilling injury, fungal decay, and shriveling affected the quality of vegetable papayas during storage. The verified suitable storage conditions were 13℃ with a relative humidity of 90%. Under these conditions, the fruit maintained a good quality for 3 weeks. During storage, the contents of maric acid and ascorbic acid in vegetable papaya increased, whereas the sugar content decreased. Furthermore, the vegetable papaya showed no surface discoloration, increased respiratory rate, or decrease in fruit firmness during storage at the suitable temperature.

　ダイコンのポリフェノール酸化酵素（PPO）をフロログルシノールを基質として，硫安分画，イオン交換クロマト，疏水クロマトおよびゲル濾過により精製した。本酵素は192倍に精製され，回収率は15％であった。精製酵素はSDS-PAGEで単一バンドを呈した。本酵素の分子量はゲル濾過で44 kDa，SDS-PAGEで45.7 kDaと推定された。本酵素は1，3，5-トリヒドロキシベンゼンであるフロログルシノールを強く酸化し，それに対するK_m値は2 mMであった。本酵素は同時に1，2，3-トリヒドロキシベンゼンであるピロガロールおよび没食子酸を酸化したが，クロロゲン酸やドーパミンのようなo-ジフェノール類は酸化しなかった。本酵素はパーオキシダーゼ（POD）活性を同時に有し，PODとしては259倍に精製され，回収率は20％であった。本酵素のPPOおよびPOD活性の最適pHはそれぞれ8及び5であり，PPOはpH 3.0～10.0の範囲で，PODは3.0～11.0の範囲で5℃，20時間安定であった。熱安定性においては両活性とも50℃まで安定であった。また，両活性とも終濃度10 mMにおいて，ジエチルジチオカルバミン酸ナトリウム，シアン化カリウムのような金属酵素阻害剤，還元剤であるL-アスコルビン酸およびジフェノール類であるクロロゲン酸やヒドロキノンにより強く阻害された。

　The microflora of kefir grains is highly varied Seven varieties of microflora with varying properties were compared in this study. A previous report suggested that Candida kefir, one of the main yeast species in kefir,causes opportunistic infections. Different combinations of the strains,exept Candida kefir, present in kefir grains were examined. ① The weight of kefir grains increased at all combinations. The kefir grain weight,except those of the genus Candida,showed an increase. ② Although it was thought that yeast played a role in imparting rigidity to the kefir grains, Lactobacillus kefiri GKL-2 and L. kefiranofaciens GKL-28 were found to play the main role in imparting rigidity.

　The protein disulfide isomerase (PDI) enzyme is involved in the formation of disulfide bonds. Here we attempted to purify PDI from wheat grain (Triticumaestivum cv. Haruyutaka). As a result of DEAE-Sepharose Fast Flow and affinity chromatography purification, 30.74units of PDI activity／100g of wheat grain were observed in the adsorbed fraction from the affinity chromatography column. The molecular weight of this fraction was63kDa as determined by SDS-PAGE analysis. N-terminal amino acid sequencing of this63－kDa protein showed that the sequences of wPDI and this63－kDa protein shared79%identity. On the basis of this result, we assumed that the63－kDa protein that we purified from wheat (Haruyutaka) grain is the same as wPDI, which we used for genetic information, and that our expression of this protein was successful.