SummarySuspension-cultured poplar (Populus alba) cells produce two distinct endo-1,4-b-glucanases, one of which is released in the extracellular culture medium and the other localized in their walls. Two cDNA clones, PopCel1 and PopCel2, isolated from a poplar cDNA library, encode the extracellular and the wallbound endo-1,4-b-glucanases, respectively, based upon deduced amino acid sequences. The products of these two genes contained domains conserved in endo-1,4-b-glucanase (family 9) and showed 91.5% amino acid identity. The levels of both PopCel1 and PopCel2 mRNAs increased during the lag phase of growth and decreased rapidly during the linear phase. After the levels had decreased, they were again increased by addition of sucrose to the culture medium and further enhanced by the addition of 2,4-dichlorophenoxyacetic acid (2,4-D) in the presence of sucrose. The accumulation of the mRNAs was correlated with the solubilization of cello-oligosaccharides. Cello-oligosaccharides and xyloglucan were also solubilized from the wall preparations of poplar cells incubated with enzyme preparations from the extracellular culture medium and walls. An antibody against both PopCel proteins reduced the production of cello-oligosaccharides by the extracellular enzyme by 90% and that by the wall-bound enzyme by 55%, and also prevented xyloglucan solubilization. The results show that the accumulation of poplar endo-1,4-b-glucanases is regulated indirectly by auxin in the presence of sucrose and can act on cellulose in suspension-cultured poplar cells.

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To investigate the fine substrate specificities of four highly purified exo-type cellulases (Exo-A from Aspergillus niger, CBHI and CBHII from Trichoderma reesei, and Ex-1 from Irpex lacteus), water-soluble substrates such as barley glucan, xyloglucan from tamarind (Tamarindus indica L.), and their oligosaccharides were employed. Four exo-type cellulases immediately hydrolyzed 3-O-beta-D-cellotriosylglucose to produce cellobiose and laminaribiose. In contrast, CBHII showed no hydrolytic activity towards 3(2)-O-beta-D-cello-biosylcellobiose, which was hydrolyzed to cellobiose by the other exo-type cellulases. These cellulases hydrolyzed the internal linkages of barley glucan and lichenan in an endo-type fashion to produce cellobiose and mix-linked oligosaccharides as main products. The DP-lowering activities of the four exo-type cellulases on barley glucan were in the order of Ex-1, CBHII, Exo-A, and CBHI. Based on gel permeation chromatography analysis of the hydrolysates, Ex-1 seemed to attack the internal cellobiosyl unit adjacent to beta-1,3-glucosidic linkages in barley glucan molecule more frequently than did the other cellulases. Xyloglucan was hydrolyzed only by CBHI and CBHII, and produced hepta-, octa-, and nona-saccharides. In addition, a xyloglucan tetradecasaccharide (XG14) was split only to heptasaccharide (XG7) by CBHI and CBHII.

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Analysis of isozymes was carried out against wild and cultivated commercial stocks of Flammulina velutipes to analyze their genetic differences. Esterase isozymes from F. velutipes showed many bands and variations among the different stocks on the gel. The stocks of F. velutipes in Japan were largely classified into three groups (tentatively named groups A, B, and C) according to the cluster analysis of esterase isozymes. Some characteristics of the three groups were examined. Group C was characterized by a larger spore size, slower spawn running, and a paler pileus color than groups A and B. Furthermore, group B showed a smaller spore size, slower spawn running, and paler pileus color than group A.

Summary Hypsyzigus marmoreus (HM), an edible mushroom, has several effects, including antitumor, antioxidant and anti-allergy properties. On the other hand, the possibly useful effect of HM in diabetic mice has not as yet been elucidated. In this study, we showed treatment with a water soluble extract from HM (EHM) to reduce fat deposits without affecting body weight loss in KK-A y mice. EHM treatment also abolished the expressions of proinfl ammatory adipokines, such as tumor necrosis factor ␣ and monocyte chemoattractant protein 1, as compared with vehicle treatment. The expressions of uncoupling protein 3 and peroxisome proliferator-activated receptor gamma coactivator 1␣ in the soleus muscles of EHM treatment groups were signifi cantly elevated as compared to those in vehicle-treated muscle tissues. These results raise the possibility that EHM can regulate both obesity and insulin resistance.

Acetobacter xylinum has been used for many years as a model system for the study of cellulose biosynthesis. Interestingly, in addition to cellulose biosynthesis, this bacterium has also produced cellulolytic enzymes. 1) However, the relation between the two products has not been made clear. Furthermore, it is reported that some strains of Acetobacter have accumulated a water soluble polysaccharide called acetan, 2) which has a similar structure to xanthan. 3,4) Cellulose is an insoluble 1,4 glucan, but acetan is a soluble sugar, which has the same backbone as cellulose. Furthermore it has attached side chain composed of glucose, mannose, glucuronic acid and rhamnose and the composition of those sugars is 4:1:1:1 (glucose:mannose: glucuronic acid : rhamnose). It was reported that Acetobacter acetigenum produced various carbohydrates, cellobiose, cellotriose, cellotetraose and fructose growing in a defined medium containing glucose. 5) Valla et al. 6) have shown a new extracellular polysaccharide from a cellulose negative strain of A. xylinum ATCC10245. In that report they showed that the polysaccharide contains glucose, mannose, rhamnose, and glucuronic acid in a molar ratio approximating 3:1:1:1. Partial acid hydrolysis results in release of glucose, rhamnose, and a disaccharide consisting of two glucose units. They speculated that this disaccharide might be gentiobiose, but the origin of these sugars has not been clarified. We also detected gentiobiose and various cello oligosaccharides in the culture broth of A. xylinum. In this paper we discuss what has been the real origin of various cello oligosaccharides synthesized during culture. First, the sugars produced in the Hestrin and Schramm (SH) 7) medium during the static culture of A. xylinum