从种内、种间化感作用分析入侵种薇甘菊及其近邻种的非协同进化趋势

为预测入侵植物与其邻近物种间的非协同进化趋势,分别提取薇甘菊(Mikania micrantha)及其近邻种五爪金龙(Ipomoea cairica)、葛藤(Pueraria lobata)和鸡矢藤(Paederia scandens)的叶片水提液处理幼苗,对薇甘菊及其近邻种的种内、种间化感作用进行研究。结果表明,薇甘菊对3种近邻种的化感作用呈现不同趋势(SE=0.50, 0.61,–0.16),但种内存在较强的化感促进作用(SE=0.61),说明其种内化感竞争较弱;葛藤的种内化感促进作用(SE=0.32)弱于薇甘菊,种间的化感促进作用与薇甘菊相似(SE=0.52, 0.50);五爪金龙种内化感促进作用(SE=0.06)弱于薇甘菊和葛藤(SE=0.32),种间促进作用(SE=0.24)弱于薇甘菊(SE=0.61);鸡矢藤的种内、种间化感作用均表现为抑制作用(SE=–0.18,–0.07),说明种内、种间化感竞争较强。野外调查表明4种植物分布的频度和多度均表现为薇甘菊葛藤五爪金龙鸡矢藤,这与化感竞争力结果一致。可见,种内与种间化感作用在入侵植物与近邻植物的综合竞争力中扮演着极为重要的作用,这为入侵种与近邻种之间的非协同进化趋势指明了方向。     

Structural variation in the O-specific polysaccharides of Klebsiella pneumoniae serotype O1 and O8 lipopolysaccharide: evidence for clonal diversity in rfb genes

The O-polysaccharide fraction of the lipopolysaccharide from Klebsiella pneumoniae serotype O8 was found to comprise two galactose-containing homopolymers. Structural analysis, using chemical and high-field nuclear magnetic resonance (NMR) techniques, established that the K. pneumoniae O8 polysaccharides are composed of the linear, disaccharide repeating units OAc 1 2/6 →3)-β-d -Galf-(1 →3)-α- d -Galp-(1→d -Galactan I-OAc →3)-α-d -Galp-(1 →3)-β-d -Galp-(1→d -Galactan II. K. pneumoniae O8 mutant RFK-1 was isolated by resistance to phage KO1-2; strain RFK-1 expressed only d -galactan I-OAc. The ¹H- and ¹³C-NMR resonances from this O-polysaccharide indicate that all of the O-acetyl groups within the K. pneumoniae O8 polysaccharide are carried on d -galactan I and O-acetylation occurs only on the β- d -galactofuranose residues; 60% of the available β- d -galactofuranose residues are non-acetylated. The O-acetylation of the remaining residues is equally distributed between the O-2 and O-6 positions. The carbohydrate backbone structures in the O8 polysaccharide are identical to d -galactan I and II expressed by K. pneumoniae O1, accounting for the antigenic cross-reaction between strains belonging to serotypes O1 and O8. However, the O1 polysaccharides are not acetylated and the O-acetyl groups present in the K. pneumoniae serotype O8 polysaccharides provide a structural basis for their recognition as distinct serotypes. The rfb (O-polysaccharide biosynthesis) gene cluster of K. pneumoniae serotype O1 determines the synthesis of d -galactan I. rfb_Kpo1-specific gene probes were used to examine conservation in the rfb gene clusters of other K. pneumoniae serotypes which produce d -galactan I. Six O1 strains were examined and all showed hybridization with rfb_KpO1 probes under conditions of high stringency. Three serotype O2 strains produce d -galactan I and these strains also contained DNA sequences recognized by rfb_KpO1 probes under high stringency. The physical maps of these homologous rfb chromosomal regions showed some polymorphism. Surprisingly, the rfb_KpO8 region from K. pneumoniae serotype O8 was only recognized by rfb_KpO1 probes under low-stringency hybridization conditions, providing evidence for two substantially different clonal groups of rfb genes from K. pneumoniae strains with structurally related O-antigens.     

Anti-diabetic potential of Pueraria lobata root extract through promoting insulin signaling by PTP1B inhibition

Type 2 diabetes mellitus is a fast-growing epidemic affecting people globally. We initiated the project by searching the possible target of the Pueraria lobata root extract (P. lobata). We conducted the IC₅₀ assays of P. lobata on the four diabetes-related proteins: PTP1B, TCPTP, SHP-2 and DPP-4. Results indicated that P. lobata exhibited high PTP1B inhibitory activity with IC₅₀ of 0.043 mg/ml. Treated insulin-resistant HepG2 cells with 0.0115 mg/ml of P. lobata increased the glucose uptake by two times compared with the negative control. Further, we performed OGTT test on the diabetic C57BL/6 male mice. 20% decreased blood glucose (AUC) was obtained with a dose of 1 g/kg P. lobata compared with the negative control. Herein, we were able to demonstrate the antidiabetic effects of P. lobata might be related to the inhibition of PTP1B and therefore, bettering the insulin signaling pathway.     

A Simple Transductional Method for Construction of Adenylate- cyclase or cAMP Receptor Protein-deficient Mutants of Escherichia coli K-12

The substrate specificity of α-d-xylosidase from Bacillus sp. No. 693–1 was further investigated. The enzyme hydrolyzed α-1,2-, α-1,3-, and α-1,4-xylobioses. It also acted on some heterooligosaccharides such as O-α-d-xylopyranosyl-(1→6)-d-glucopyranose, O-α-d-xylopyranosyl-(1→6)-O-β-d-glucopyranosyl-(1→4)-d-glucopyranose, O-α- d-xylopyranosyl-(1→6)-O-d-glucopyranosyl-(1→4)-O-[α-d-xylopyranosyl-(1→6)]-d-glucopyranose, and O-α-d-xylopyranosyl-(1→3)-l-arabinopyranose. The enzyme was unable to hydrolyze tamarinde polysaccharides although it could hydrolyze low molecular weight substrates with similar linkages.     

Ultrasonic degradation, purification and analysis of structure and antioxidant activity of polysaccharide from Porphyra yezoensis Udea

The chemical structure and antioxidant of natural and ultrasonic degraded polysaccharides from Porphyra yezoensis Udea was investigated. The degraded polysaccharide (PYPS_UD) was purified, and F2 (a homogeneous fraction) was obtained. FT-IR, ¹H and ¹³C NMR spectral analysis revealed that F2 have typical porphyran structure. It has a backbone of alternating (1 → 4)-3,6-anhydro-α-l-galactopyranose) units and (1 → 3)-linked β-d-galactose or (1 → 4)-linked α-l-galactose 6-sulfate units. The result ascertained ultrasound degradation did not change the main structure of polysaccharides in the test conditions. Antioxidant proved that the activity of scavenging superoxide and hydroxyl radical is F₂ > V_C > PSPY_UD > PSPY. It was possible that ultrasonic treatment is an effective way for enhancing PSPY's antioxidant activity ascribing to decreasing molecular weight of polysaccharides.     

Cross-Reactive Polysaccharides from Trypanosoma cruzi and Fungi (Especially Dactylium dendroides)1

ABSTRACT. Cross-reactivity between fungal and Trypanosoma cruzi polysaccharides, owing to common residues of β-D-galactofuranose, β-D-galactopyranose, and α-D-mannopyranose, was demonstrated by using a) rabbit immune sera against T. cruzi epimastigotes and b) sera from patients with Chagas’disease. Several chagasic (Ch) sera precipitated partly purified galactomannans from Aspergillus fumigatus and from T. cruzi epimastigotes and also the galactoglucomannan from Dactylium dendroides. Reaction of one Ch serum with T. cruzi galactomannan (GM) was completely inhibited by synthetic β-D-Galf-(1 → 3)-Me α-D-Manp, and that of another Ch serum with a purified D. dendroides galactoglucomannan (GGM) was partly inhibited by (1 → 6)-linked (81%) or by (1 - 3)-linked (33%) β-D-Galf-Me α-D-Manp. The β-D-Galf-(1 → 3)-α-D-Manp epitope was present in both T. cruzi and D. dendroides polysaccharides. Rabbit anti-T. cruzi antisera precipitated A. fumigatus GM, T. cruzi antigenic extracts containing the lipopeptidophosphoglycan (LPPG), T. cruzi alkali-extracted GM, a synthetic GM, and D. dendroides GGM. Weak reactivities were obtained for a Torulopsis lactis-condensi GM containing β-D-Galp terminal residues and for baker's yeast mannan with α-D-Manp-(1 - 3)-α-D-Manp-(1- → 2)-α-D-Manp-(1 → 2) side chains. An anti-LPPG rabbit serum precipitated D. dendroides GGM—a reaction inhibited (82%) by β-D-Galf-(1 → 3)-Me α-D-Manp and, less efficiently, by a (1 → 5)-linked β-D-Galf-tetrasaccharide. Sera from mice immunized with D. dendroides whole cells reacted with CL-strain trypomastigotes as shown a) by indirect immunofluorescence, b) by a Staphylococcus adherence test, but were not lytic. Mice immunized with D. dendroides were not protected against a challenge with virulent T. cruzi trypomastigotes.     

Comparative studies of asparagine-linked oligosaccharide structures of rat liver microsomal and lysosomal beta-glucuronidases

The sugar chains of microsomal and lysosomal β-glucuronidases of rat liver were studied by endo-β-N-acetylglucosaminidase H digestion and by hydrazinolysis. Only a part of the oligosaccharides released from microsomal β-glucuronidase was an acidic component. The acidic component was not hydrolyzed by sialidase and by calf intestinal and Escherichia coli alkaline phosphatases, but was converted to a neutral component by phosphatase digestion after mild acid treatment indicating the presence of a phosphodiester group. The neutral oligosaccharide portion of microsomal enzyme was a mixture of five high mannose-type sugar chains: (Manα1 → 2)_0~4 [Manα1 → 6(Manα1 → 3)Manα1 → 6(Manα1 → 3)Manβ1 → 4GlcNAcβ1 → 4GlcNAc]. In contrast, lysosomal enzyme contains only Manα1 → 6 (Manα1 → 3) Manα1 → 6(Manα1 → 3) Manβ1 → 4GlcNAcβ1 → 4GlcNAc. The result indicates that removal of α1 → 2-linked mannosyl residues from (Manα1 → 2)₄[Manα1 → 6(Manα1 → 3)Manα1 → 6(Manα1 → 3)Manβ1 → 4GlcNAcβ1 → 4GlcNAc → Asn] starts already in the endoplasmic reticulum of rat liver.     

Structural studies of the carbohydrate moiety of human antithrombin III

Human antithrombin III contains four asparagine-linked sugar chains in one molecule. The sugar chains were quantitatively released as radioactive oligosaccharides from the polypeptide portion by hydrazinolysis followed by N-acetylation and NaB³H₄ reduction. All of the oligosaccharides, thus obtained, contain N-acetylneuraminic acid. A same neutral nonaitol was released from all acidic oligosaccharides by sialidase treatment. By combination of the sequential exoglycosidase digestion and methylation analysis, their structures were elucidated as NeuAcα2 → 6Galβ1 → 4GlcNAcβ1 → 2Manα1 → 6-(NeuAcα2 → 6Galβ1 → 4GlcNAcβ1 → 2Manα1 → 3)Manβ1 → 4GlcNAcβ1 → 4GlcNAc, Galβ1 → 4GlcNAcβ1 → 2Manα1 → 6(NeuAcα2 → 6Galβ1 → 4GlcNAcβ1 → 2Manαl → 3)Manβ1 → 4GlcNAcβ1 → 4GlcNAc, and NeuAcα2 → 6Galβ1 → 4GlcNAcβ1 → 2Manα1 → 6(Galβ1 → 4GlcNAcβ1 → 2Manα1 → 3)Manβ1 → 4GlcNAcβ1 → 4GlcNAc.     

Purification,Chemical Characterization,and Bioactivity of an Extracellular Polysaccharide Produced by the Marine Sponge Endogenous Fungus <Emphasis Type="Italic">Alternaria</Emphasis> sp. SP-32

Marine sponges are ancient and simple multicellular filter-feeding invertebrates attached to solid substrates in benthic habitats and host a variety of fungi both inside and on their surface because of its unique ingestion and digest system. Investigation on marine sponge-associated fungi mainly focused on the small molecular metabolites, yet little attention had been paid to the extracellular polysaccharides. In this study, a homogeneous extracellular polysaccharide AS2-1 was obtained from the fermented broth of the marine sponge endogenous fungus Alternaria sp. SP-32 using ethanol precipitation, anion-exchange, and size-exclusion chromatography. Results of chemical and spectroscopic analyses showed that AS2-1 was composed of mannose, glucose, and galactose with a molar ratio of 1.00:0.67:0.35, and its molecular weight was 27.4 kDa. AS2-1 consists of a mannan core and a galactoglucan chain. The mannan core is composed of (1→6)-α-Manp substituted at C-2 by (1→2)-α-Manp with different degrees of polymerization. The galactoglucan chain consists of (1→6)-α-Glcp residues with (1→6)-β-Galf residues attached to the last glucopyranose residue at C-6. (1→6)-β-Galf residues have additional branches at C-2 consisting of disaccharide units of (1→2)-β-Galf and (1→2)-α-Glcp residues. The glucopyranose residue of the galactoglucan chain is linked to the mannan core. AS2-1 possessed a high antioxidant activity as evaluated by scavenging of 1,1-diphenyl-2-picrylhydrazyl and hydroxyl radicals in vitro. AS2-1 was also evaluated for cytotoxic activity on Hela, HL-60, and K562 cell lines by the MTT and SRB methods. The investigation demonstrated that AS2-1 was a novel extracellular polysaccharide with different characterization from extracellular polysaccharides produced by other marine microorganisms.     

An expeditious synthesis of blood-group antigens,ABO histo-blood group type II antigens and xenoantigen oligosaccharides with amino type spacer−arms

Blood group oligosaccharides are one of the most clinically important antigen families and they may also act as secondary ligands for bacterial toxins from Escherichia coli and Vibrio cholerae. Herein we report the synthesis of spacered (sp = CH₂CH₂CH₂NH₂) glycosides of A antigen {α-D-GalNAc-(l→3)-[α-L-Fuc-(l→2)]-β-D-Gal-}, B antigen{α-D-Gal-(l→3)-[α-L-Fuc-(l→2)]-β-D-Gal-}, LewisX{α-D-Gal-(l→4)-[α-L-Fuc-(l→3)]-β-D-GlcNAc-}, A type-II {α-D-GalNAc-(l→3)-[α-L-Fuc-(l→2)]-β-D-Gal-(1→4)-β-D-GlcNAc-}, B type-II {α-D-Gal-(l→3)-[α-L-Fuc-(l→2)]-β-D-Gal-(1→4)-β-D-GlcNAc-}, H type-II{α-L-Fuc-(l→2)-β-D-Gal-(1→4)-β-D-GlcNAc-}, xenoantigen {α-D-Gal-(l→3)-β-D-Gal-(1→4)-[α-L-Fuc-(l→2)]-β-D-GlcNAc-} and Linear B Type II {α-D-Gal-(l→3)-β-D-Gal-(1→4)-β-D-GlcNAc-} useful for a range of biochemical investigations. This linker was chosen so as to facilitate the future conjugation of the antigens to proteins or other molecules. We also measured the affinities of some synthesized oligosaccharides against El Tor CTB strain from V. cholera.     

OLIGOSACCHARIDE STORAGE IN BRAINS FROM PATIENTS WITH FUCOSIDOSIS,GM1-GANGLIOSIDOSIS AND GM2-GANGLIOSIDOSIS (SANDHOFF'S DISEASE)1

Abstract— Analysis of whole autopsy brain from a patient with fucosidosis (α-fucosidase deficiency) revealed minor storage of H-antigen glycolipid [Fuc (α, 1→2) Gal-GlcNAc-Gal-Glc-Ceramide] and a slightly abnormal ganglioside composition in the form of a two-fold elevation of G_M1 and the presence of a fucose-containing glycolipid (a minor component) which co-migrated with G_D1a. The major storage materials in fucosidosis brain were an oligosaccharide (Fuc-Gal-GlcNAc-Man[Fuc-Gal-GlcNAc-Man]-ManGlcNAc) and a disaccharide [Fuc(α, 1→6)-GlcNAc] in the approximate ratio of 5:1. Lesser amounts of a related oligosaccharide (Gal-GlcNAc-Man[Gal-GlcNAc-Man]-Man-GlcNAc) were isolated from the brain of patients with G_M1-gangliosidosis (Types I and II) where the major storage material is known to be G_M1-ganglioside (Gal (β, 1→3)GalNAc(β, 1→4) [NeuNAcf(α, 2→3) Gal(β, 1→4)Glc-Ceramide). Similarly, a related oligosaccharide (GlcNAc-Man [GlcNAc-Man]-Man-GlcNAc) was isolated from the brain of a patient with a total deficiency of N-acetyl-β-d -hexosaminidase (Sandhoff variant of G_M2-gangliosidosis) where the major storage products are known to be G_M2-ganglioside (GalNAc (β 1→4) [NeuNAc (α, 2→3)Gal(β, 1→4)Glc-Ceramine) and its asialo derivative. These studies indicate that glycoproteins containing at least 2 mol of l -fucose per oligosaccharide unit are normally catabolized in human brain. Further, it appears that such glycoproteins are initially catabolized by an endo-N-acetylglucosaminidase to release an oligosaccharide which is then degraded by the sequential action of exo-glycosidases.     

A Novel Polysaccharide Separated from Panax Notoginseng Residue Ameliorates Restraint Stress- and Lipopolysaccharide-induced Enteritis in Mice

Polysaccharides are rich in Panax notoginseng residue after extraction. This study aims to explore the structural characteristics of PNP-20, which is a homogeneous polysaccharide, separated from P. notoginseng residue by fractional precipitation and evaluate the anti-enteritis effect of PNP-20. The structure of PNP-20 was determined by spectroscopic analyses. A mouse model with enteritis induced by restraint stress (RS) and lipopolysaccharide (LPS) was used to evaluate the pharmacological effect of PNP-20. The results indicated that PNP-20 consisted of glucose (Glc), galactose (Gal), Mannose (Man) and Rhamnose (Rha). PNP-20 was composed of Glcp-(1→, →4)-α-Glcp-(1→, →4)-α-Galp-(1→, →4,6)-α-Glcp-(1→, →4)-Manp-(1→ and →3)-Rhap-(1→, and contained two backbone fragments of →4)-α-Glcp-(1→4)- α-Glcp-(1→ and →4)-α-Galp-(1→4)-α-Glcp-(1→. PNP-20 reduced intestinal injury and inflammatory cell infiltration in RS- and LPS-induced enteritis in mice. PNP-20 decreased the expression of intestinal tumor necrosis factor-α, NOD-like receptor family pyrin domain containing 3, and nuclear factor-κB and increased the expression of intestinal superoxide dismutase 2. In conclusion, PNP-20 may be a promising material basis of P. Notoginseng for the treatment of inflammatory bowel disease.     

葛(豆科)叶的解剖学研究

利用光学显微镜和扫描电镜观察了葛(Pueraria lobata)叶的解剖学特征。结果表明,葛叶片的上、下表皮都只有一层表皮细胞,上表皮比下表皮厚。上、下表皮都有腺毛和非腺毛。气孔主要分布在下表皮,下表皮的气孔密度为(261±17)mm-2,上表皮只有(6±3)mm-2。叶肉由两层栅栏组织细胞和一层海绵组织细胞构成。叶肉细胞中有丰富的叶绿体。在栅栏组织和海绵组织之间有一层平行于叶脉的薄壁细胞。叶脉中含有大量的草酸钙晶体。葛叶的这些形态特征与其喜阳、耐旱的特点相适应。     

Spirostanol saponins from Paris polyphylla,structures of polyphyllin C,D, E and F

The structures of four new saponins, polyphyllin C, D, E and F, isolated from the tubers of Paris polyphylla have been elucidated as diosgenin-3-O-α-l-rhamnopyranosyl(1→3)-β-d-glucopyranoside, diosgenin-3-O-α-l-rhamnopyranosyl(1→3)- [α-l-arabinofuranosyl(1→4)]-β-d-glucopyranoside, diosgenin-3-O-α-l-rhamnopyranosyl(1→2)-α-l-rhamnopyranosyl (1→4)[α-l-rhamnopyranosyl(1→3)]-β-d-glucopyranoside and diosgenin-3-O-α-l-rhamnopyranosyl(1→4)[α-l- rhamnopyranosyl(1→3)][β-d-glucopyranosyl(1→2)]-α-l-rhamnopyranoside, respectively, on the basis of chemical and spectral data.     

Delay of tomato fruit ripening by an oligosaccharide N-glycan. Interactions with IAA, galactose and lectins

The unconjugated N-glycans Manα1→6(Manα→3)Manα1→6(Manα1→3)-Manβ1→4GlcNAc (Man₅GlcNAc) and Manα1→6(Manα1→3)(Xy1β1→2)-Manβ1→4GlcNAcβ1→4(Fucα1→3)GlcNAc were shown to stimulate and delay ripening of mature green tomato fruit (Lycopersicon esculentum Mill. cv. Rutgers) at 1 and 10 ng (g fresh weight)⁻¹, respectively (Priem and Gross 1992, Plant Physiol. 98: 399–401). Also, the occurrence and structure of 10 unconjugated N-glycans, including Man₅GlcNAc, in tomato fruit were recently reported (Priem et al. 1993, Plant Physiol. 102: 445–458). In this work, we studied the potential interaction between Man₅GlcNAc and several compounds by using a system that allowed pericarp discs to be kept up to 14 days after excision. Studies were performed to determine the effect of Man₅GlcNAc, indole-3-acetic acid (IAA), concanavalin A and tomato lectin on ripening as defined by red coloration of the skin. Ripening in pericarp discs, unlike that in intact fruit, was unaffected by 1 ng (g fresh weight)⁻¹ Man₅GlcNAc. However, discs showed delayed ripening with 10 ng (g fresh weight)⁻¹, and the delay of coloration was galactose dependent. Man₅GlcNAc at 10 ng (g fresh weight)⁻¹ inhibited the stimulation of coloration induced by 100 μ IAA in the presence of 40 μg (g fresh weight)⁻¹ galactose. Man₅GlcNAc lost biological activity in the presence of the two lectins. These results support the possible interaction of IAA and various oligosaccharides during plant growth and development, and for the first time suggest a physiological significance for tomato lectin.     

Chemical analysis of new water-soluble (1→6)-, (1→4)-α, β-glucan and water-insoluble (1→3)-, (1→4)-β-glucan (Calocyban) from alkaline extract of an edible mushroom, Calocybe indica (Dudh Chattu)

Two different glucans (PS-I, water-soluble; and PS-II, water-insoluble) were isolated from the alkaline extract of fruit bodies of an edible mushroom Calocybe indica. On the basis of acid hydrolysis, methylation analysis, periodate oxidation, and NMR analysis ((1)H, (13)C, DEPT-135, TOCSY, DQF-COSY, NOESY, ROESY, HMQC, and HMBC), the structure of the repeating unit of these polysaccharides were established as: PS-I: →6)-β-D-Glcp-(1→6)-β-D-glcp-(1→6)-)-β-D-Glcp-(1→ α-D=Glcp (Water-soluble glucan). PS-II: →3)-β-D-Glcp-(1→3)-β-D-glcp-(1→3)-)-β-D-Glcp-(1→3)-β-D-Glcp-(1→ β-D-Glcp (Water-insoluble glucan, Calocyban).     

Assignment of signals of the carbon-13 magnetic resonance spectrum of a selected polysaccharide: Comments on methodology

The mannan from Rhodotorula glutinis contains alternate (1→3)- and (1→4)- linked β-D-mannopyranose residues (1) and its carbon-13 magnetic resonance spectrum displays 12 signals. These were assigned in terms of the positions of their parent nuclei in the sugar rings [but not whether the signals arose from a (1→3)- or (1→4)-linked residue] by preparation of D-mannans from specifically deuterated D-glucoses and observation of α- and β-deuterium isotope-effects. Individual assignments could then be made for carbon atoms of each unit by using the spectra of known oligo- and polysaccharides. The signal displacements of certain ¹³C nuclei observed on O-methylation were compared with those obtained on O-mannosylation in order to determine whether methyl ethers could be used as model compounds for signal assignments in spectra of mannose-containing polysaccharides. The displacements observed were in the same direction and of a similar order of magnitude. An assessment is made of the use of the various techniques in assigning signals of polysaccharides and their possible interpretation in terms of chemical structure.     

Substrate recognition of the catalytic α-subunit of glucosidase II from Schizosaccharomyces pombe

The recombinant catalytic α-subunit of N-glycan processing glucosidase II from Schizosaccharomyces pombe (SpGIIα) was produced in Escherichia coli. The recombinant SpGIIα exhibited quite low stability, with a reduction in activity to <40% after 2-days preservation at 4 °C, but the presence of 10% (v/v) glycerol prevented this loss of activity. SpGIIα, a member of the glycoside hydrolase family 31 (GH31), displayed the typical substrate specificity of GH31 α-glucosidases. The enzyme hydrolyzed not only α-(1→3)- but also α-(1→2)-, α-(1→4)-, and α-(1→6)-glucosidic linkages, and p-nitrophenyl α-glucoside. SpGIIα displayed most catalytic properties of glucosidase II. Hydrolytic activity of the terminal α-glucosidic residue of Glc₂Man₃-Dansyl was faster than that of Glc₁Man₃-Dansyl. This catalytic α-subunit also removed terminal glucose residues from native N-glycans (Glc₂Man₉GlcNAc₂ and Glc₁Man₉GlcNAc₂) although the activity was low.     

Structure of desacylsaponins obtained from the bark of Quillaja saponaria

A triterpenoid saponin mixture (so-called quillajasaponin) obtained from the bark of Quillaja saponaria was treated with weak alkali and two major desacylsaponins were isolated. On the basis of chemical and spectral evidence, they were determined as 3-O-β-D-galactopyranosyl-(1 → 2)-[β-D-xylopyranosyl-(1 → 3)]-β-D-glucuronopyranosyl quillaic acid 28-O-β-D-apiofuranosyl-(1 → 3)-β-D-xylopyranosyl-(1 → 4)-α-L-rhamnopyranosyl-(1 → 2)-β-D-fucopyranoside and 28-O-β-D-apiofuranosyl-(1 → 3)-β-D-xylopyranosyl-(1 → 4)-[β-D-glucopyranosyl-(1 → 3)]-α-L-rhamnopyranosyl-(1 → 2)-β-D-fucopyranoside. Diazomethane degradation providing selectively the 28-O-glycoside from the 3,28-O-bisglycoside was a useful method for the structure elucidation.