Purification and Characterization of α-Glucosidases from Spinach Seeds

Four molecular forms of α-glucosidase were isolated from spinach seeds by several kinds of chromatography. The molecular masses of α-glucosidases Ⅰ,Ⅱ,Ⅲ,and Ⅳ were 78,78,82 and 82kDa by SDS-PAGE, and 62,62,190,and 70kDa by gel filtration, respectively. α-Glucosidases Ⅰand Ⅱ showed similar enzymatic properties. The Km for soluble starch was about 10 times lower than that for maltose, and they had higher activity not only towards malto-oligosaccharides but also towards α-glucans. The optimum pH was 4.5-5.5 and about 50% of the activity remained after incubation at 71℃ for 20 min. On the other hand, α-glucosidases Ⅲ and Ⅳ showed similar enzymatic propreties. The Km for maltose was 3-4 times lower than for solble starch, and they had high activity toward malto-oligosaccharides but faint activity towards α-glucnas. The optimum pH was 4.5-5.0 and no activity was found after incubation at 70℃ for 20 min. However, anti-α-glucosidase Ⅲ serum precipitated specifically with α-glucosidase Ⅲ.α－グルコシダーゼの分子多型が各種クロマトグラフィーによりホウレンソウ種子から単離された。α－グルコシダーゼⅠ、Ⅱ、Ⅲ、Ⅳの分子量は、それぞれSDS－PAGEにより78、78、82、82kDA、ゲル濾過のより62,62,190、70kDであった。α-グルコシダーゼⅠとⅡは、可溶性デンプンを基質とした際のKm値がマルトースよりも約10倍低く、さらに、α－グルカンだけでなくマルトオリゴ糖に対しても高い活性を示すことから、同じような酵素的特性を持つことが示された。最適pHは4.5ｶﾗ5.5を示し、温度安定性は70℃、20分処理で約50％の残存活性を示した。一方、α－グルコシダーゼⅢとⅣは、マルトースを基質とした際のKm値が可溶性デンプンよりも3－4倍低い値を示し、マルトオリゴ糖に対しては高い活性を示すが、α－グルカンに対してはほとんど活性を示さないことから、同じような酵素的特性を有することが示された。最適pHは4.5－5.5、そして70℃、20分処理では活性が認められなかった。しかしながら、抗α－グルコシダーゼⅢ血清は、α－グルコシダーゼⅢに対してのみ特異的に沈降線を形成した

ホウレンソウ種子に存在するα-グルコシダーゼの分子多型変化

Two molecular forms of α-glucosidase were isolated from spinach seeds after storage at 4℃ by CM-cellulose column chromatography and gel filtration. The molecular masses of α-glucosidase A and B were 78 kDa and 82 kDa by SDS-PAGE, and 62 kDa and 70 kDa by gel filtration, respectively. α-Glucosidase A had high activity not only toward maltooligosaccharides but also toward α-glucans. The optimum pH was 4.5-5.5 and about 50% of the activity remained after incubation at 65℃ for 20 min. On the other hand, α-glucosidase B had high activity toward maltooligosaccharides but faint activity toward α-glucans. The optimum pH was 5.0 and no activity was found after incubation at 65℃ for 20 min. The enzymatic and immunological properties of α-glucosidase A and B were similar to those of α-glucosidase. Ⅰor Ⅱ, and α-glucosidase Ⅲ or Ⅳ, isolated from spinach seeds without 4℃ storage, respectively. These findings suggest that the α-glucosidase in spinach seeds is modified to be two molecular forms.4℃保存したホウレンソウ種子から2種のα-グリコシダーゼをCM-セルロースカラムクロマトグラフィーとゲル濾過により精製した。α-グルコシダーゼAとBの分子量はそれぞれSDS-PAGEで78kDA、82kDa、ゲル濾過で62kDa、70kDaであった。α-グルコシダーゼAはマルトオリゴ糖だけではなく可溶性デンプンに対して強い加水分解活性を示した。至適pHは4.5-5.5であり、65℃、20分処理後に約50％の残存活性を示した。一方、α-グルコシダーゼBはマルトオリゴ等に対して強い加水分解活性を示したが、可溶性デンプンに対してほとんど活性を示さなかった。至適pHは5.0であり、65℃、20分処理後に活性を消失した。α-グルコシダーゼAとα-グルコシダーゼBは、4℃保存を行わない種子に見出されたα-グルコシダーゼⅠ、Ⅱとα-グルコシダーゼⅢ、Ⅳにそれぞれ酵素化学的性質、免疫化学的性質が類似していた。これらの結果、ホウレンソウ種子に存在するα-グルコシダーゼの分子多型は2種類に収束されることが示唆された

Classification of Primary Hepatolithiasis According to Morphology of the Liver, Especially Atrophy of Hepatic Parenchyma

One hundred twenty one patients with primary hepatolithiasis (PHL) was encountered for the last 7 years. In order to elucidate how to follow and treat PHL, PHL was classified into five types (I-V) on the basis of morphological findings obtained by CT. It depends mainly on the presence of atrophy of hepatic parenchyma (AHP) and dilatation of intrahepatic bile ducts (DIBD). Methods of treatment were selected for each patient according to the classification. Type I patients comprised of 43.8% in observation group. These patient were asymptomatic and just followed since neither APH nor DIBD were observed. The remaining patients in the observation group, operation was refused or contraindicated. Most of them were asymptomatic. Surgical treatments were done on 47 patients (hepatic resection in 32 patients, surgical lithotomy in 10 and others in 5). In Type III, IV and V, hepatic resection was often performed to remove all of stones and bile stasis since improvement in hepatic function could not be expected in view of AHP. All patients were followed-up 79 months or less. In the surgically terated patients, recurrence was not observed. In observation group, no new symptome developed during the follow-up period. It was suggested, therefore, that the present classification of PHL was helpful in determining therapeutic strategy for PHL

A Stream-Weight Optimization Method for Multi-Stream HMMs Based on Likelihood Value Normalization

In the field of audio-visual speech recognition, multi-stream HMMs are widely used, thus how to automatically and properly determine stream weight factors using a small data set becomes an important research issue. This paper proposes a new stream-weight optimization method based on an output likelihood normalization criterion. In this method, the stream weights are adjusted to equalize the mean values of log likelihood for all HMMs. based on likelihood-ratio maximization which achieved significant improvement by using a large optimization data set. The new method is evaluated using Japanese connected digit speech recorded in real-world environments. Using 10 seconds speech data for stream-weight optimization, a 10% absolute accuracy improvement is achieved compared to the result before optimization. By additionally applying the MLLR (maximum likelihood linear regression) adaptation, a 23% improvement is obtained over the audio-only scheme

Audio-Visual Speech Recognition Using Lip Information Extracted from Side-Face Images

This paper proposes an audio-visual speech recognition method using lip information extracted from side-face images as an attempt to increase noise robustness in mobile environments. Our proposed method assumes that lip images can be captured using a small camera installed in a handset. Two different kinds of lip features, lip-contour geometric features and lip-motion velocity features, are used individually or jointly, in combination with audio features. Phoneme HMMs modeling the audio and visual features are built based on the multistream HMM technique. Experiments conducted using Japanese connected digit speech contaminated with white noise in various SNR conditions show effectiveness of the proposed method. Recognition accuracy is improved by using the visual information in all SNR conditions. These visual features were confirmed to be effective even when the audio HMM was adapted to noise by the MLLR method.</p