Production and characterisation of a biosurfactant isolated from Pseudomonas aeruginosa UW-1

Pseudomonas aeruginosa UW-1 produced 17–24 g L⁻¹ rhamnolipid in vegetable oil-containing media in shake flask cultures in 13 days. In time course studies of growth and rhamnolipid production in a salts medium containing 6% canola oil, total bacterial count reached 2.6 × 10¹⁰ CFU ml⁻¹ after 48 h and a maximum rhamnolipid yield of 24.3 g L⁻¹ was obtained after 9 days. Rhamnolipid components were purified and separated by chloroform-methanol extraction and TLC chromatography. The major rhamnolipid components were characterised as L-rhamnosyl-β-hydroxydecanoyl-β-hydroxydecanoate and L-rhamnosyl-L-rhamnosyl-β-hydroxydecanoyl-β-hydroxydecanoate by nuclear magnetic resonance and mass spectrometry. The components were separated preparatively by silica gel column chromatography. The recovered monorhamnosyl fraction contained no dirhamnosyl moiety while the recovered dirhamnosyl fraction contained 5% of the monorhamnosyl moiety when analyzed by HPLC. The ratio of mono- to dirhamnosyl components produced by P. aeruginosa UW-1 was determined by HPLC to be 4 : 1 by weight. Purified mono- and dirhamnosyl components had the same CMC value of 40 μg ml⁻¹ and decreased the surface tension of water to 27.7 and 30.4 dynes cm⁻¹, respectively. Received 04 April 1997/ Accepted in revised form 15 July 1997     

Unique disialosyl gangliosides from salmon kidney: Characterization of V3αFuc, IV3βGalNAc, II3(αNeuAc)2-Gg4Cer and its analogue with 4-O-acetyl-N-acetylneuraminic acid

Four unidentified acidic glycolipids (X3-X6) were isolated from the kidney of the Pacific salmon on an anion exchange column and by high performance liquid chromatography using a silica bead (Iatrobeads) column. Based on methylation analysis, chemical and enzymatic degradation, proton nuclear magnetic resonance spectroscopy and mass spectrometry, the glycon structure of X5 and X6 was identified as a unique disialosyl fucosyl-N-acetylgalactosaminyl ganglio-N-tetraose: Fucα3GalNAcβ3Galβ3GalNAcβ4[NeuAcα8NeuAcα3] Galβ4Glcβ1Cer. NMR showed that X3 and X4 were analogues of X5 and X6 and contained O-acetyl groups on C4 of the outer N-acetylneuraminic acid, first disialosyl gangliosides containing 4-O-acetyl-N-acetylneuraminic acid. The ceramides of X3 and X5 contained predominantly C24: 1, and X4 and X6 contained saturated fatty acids (C14: 0, C16: 0 and C18: 0), whereas the long chain base was exclusively sphingenine. The concentrations of X3 and X4 were 0.13 and 0.16 nmol/g of kidney respectively and those of X5 and X6, were 0.07 nmol/g each.     

Production of a novel glycolipid biosurfactant,mannosylmannitol lipid,by <Emphasis Type="Italic">Pseudozyma parantarctica</Emphasis> and its interfacial properties

The development of a novel glycolipid biosurfactant was undertaken using the high-level producers of mannosylerythritol lipids (MELs) such as Pseudozyma parantarctica, Pseudozyma antarctica, and Pseudozyma rugulosa. Besides the conventional MELs (MEL-A, MEL-B, and MEL-C), these yeasts produced an unknown glycolipid when they were cultivated in a medium containing 4% (w/v) olive oil and 4% (w/w) mannitol as the carbon source. The unknown glycolipid extracted from the culture medium of P. parantarctica JCM 11752^T displayed the spot with lower mobility than that of known MELs on TLC and provided mainly two peaks identical to mannose and mannitol on high-performance liquid chromatography after acid hydrolysis. Based on structural analysis by ¹H and ¹³C nuclear magnetic resonance, the novel glycolipid was composed of mannose and mannitol as the hydrophilic sugar moiety and was identified as mannosylmannitol lipid (MML). Of the strains tested, P. parantarctica JCM 11752^T gave the best yield of MML (18.2 g/L), which comprised approximately 35% of all glycolipids produced. We further investigated the interfacial properties of the MML, considering the unique hydrophilic structure. The observed critical micelle concentration (CMC) and the surface tension at CMC of the MML were 2.6 × 10⁻⁶ M and 24.2 mN/m, respectively. In addition, on a water-penetration scan, the MML efficiently formed not only the lamella phase (Lα) but also the myelins at a wide range of concentrations, indicating its excellent self-assembling properties and high hydrophilicity. The present glycolipid should thus facilitate the application of biosurfactants as new functional materials.     

Production and structure elucidation of di- and oligosaccharide lipids (biosurfactants) from Tsukamurella sp. nov.

The bacterium Tsukamurella sp. nov., isolated from soil, was found to produce novel glycolipids when grown on sunflower oil as the sole carbon source. The glycolipids were isolated by chromatography on silica columns and their structures elucidated using a combination of multidimensional NMR and MS techniques. The three main components are 2,3-di-O-acyl-α-d-glucopyranosyl-(1-1)-α-d-glucopyranose, 2,3-di-O-acyl-β-d-glucopyranosyl-(1-2)-4,6-di-O-acyl-α-d-glucopyranosyl-(1-1)-α-d-glucopyranose and 2,3-di-O-acyl-β-d-glucopyranosyl-(1-2)-β-d-galactopyranosyl-(1-6)-4,6-di-O-acyl-α-d-glucopyranosyl-(1-1)-α-d-glucopyranosl which are linked to fatty acids varying in chain length from C₄ to C₁₈. The glycolipids are mainly extracellular but are also found attached to the cell walls. During the cultivation the composition of the glycolipids changed from disaccharide- to tri- and tetrasaccharide lipids. The glycolipids show good surface-active behaviour and have antimicrobial properties. Received: 22 May 1998 / Received revision: 24 August 1998 / Accepted: 26 August 1998     

Establishment of cells exhibiting mutated glycolipid synthesis from mouse thymus by immortalization with SV-40 virus

Immortalization with simian virus-40 and cloning of immortalized cells from mouse thymus were performed to establish cell lines for characterization of the mode of glycolipid expression in the thymic cells. Among the 25 cell lines obtained, three lines with different morphologies were established, that is, epithelial (IMTH-E), fibroblastic (IMTH-F), and asterisk-like (IMTH-I) cells, and their glycolipids, together with those in the thymus, were determined systematically. The major glycolipids in mouse thymus were the globo- and ganglio-series, both of which, were co-expressed in the three cell lines established. However, the mode of modification of the globo- and ganglio-series was distinct for each cell line. As to the globo-series, the structures with the longest carbohydrate chain for IMTH-E, -F, and -I cells were Gb₃Cer, Gb₄Cer, and Forssman antigen, respectively, having stepwise shorter carbohydrates at the nonreducing termini. Although the acidic glycolipids in IMTH-E cells comprised GM3 and GM2, and their sulfated isomers, IMTH-F and -I cells expressed GMlb and GDlc for the α-pathway, and up to GDI a for the a-pathway of ganglio-series glycolipids. GMlb-GalNAc present in the thymus was not detected in IMTH-F and -I cells, probably due to the lower synthetic activity for the metabolic intermediate Gg₄Cer. The results indicate that the immortalization technique is useful for obtaining individual cells having unique glycolipid profiles for analysis of the functional significance and metabolism of glycolipids in the thymus. Abbreviations: Glycolipids are abbreviated according to the recommendations of the IUPAC-IUBMB Commission on Biochemical Nomenclature. Eur J Biochem 79, 11-21 (1977). The ganglioside nomenclature of Svennerholm [1] is employed throughout, except that GMlb, GMlb-GalNAc, GMlb-GaINAc-Gal, GDlc, and GDI α denote IV³ NeuAcα-Gg₄Cer, IV⁴GalNAcβ, IV³NeuAcα-Gg₄Cer, IV⁴(Galβ-3GalNAcβ),IV³NeuAcα-Gg₄Cer, IV³NeuAcα₂-Gg₄Cer, and III⁶ NeuAcα, IV³NeuAcα-Gg₄Cer, respectively. BSA, bovine serum albumin; PBS, phosphate-buffered saline; FCS, fetal calf serum; SV, simian virus; FABMS, fast atom bombardment mass spectrometry; NeuAc, N-acetylneuraminic acid; NeuGc, N-glycolylneuraminic acid; Hex, hexose: HexNAc, N-acetylhexosamine.     

Selective removal of anti-α-Gal antibodies from human serum by using synthetic α-Gal epitope on a core-shell type resin

A novel α-Gal resin was chemo-enzymatically synthesized for the efficient adsorption of anti-α-Gal antibodies in human serum for xenotransplantation. To covalently conjugate a hexanoate linker with lactose and N-acetylglucosamine, both acceptor sugars were acetylated and brominated. Then, α-and β-galactoses were sequentially added to the linker-containing saccharides at their non-reducing ends by using recombinant α-(1,3)-and β-(1,4)-galactosyltransferases from E. coli. Finally, the synthesized α-Gal derivatives were immobilized on HiCore, a core-shell type resin, that was functionalized with amino groups on the shell region, as a packing material on-column. Using this method we were able to demonstrate that the α-Gal HiCore resin had a reduced level of non-specific protein adsorption compared with the commercially available polystyrene supports, TentaGel, and agarose-based supports, when Lectin BS-I was used as the model binding protein. Furthermore, the α-Gal HiCore resin was more efficient at eliminating anti-α-Gal IgGs from the total human IgGs through immunoadsorption than the other two α-Gal resins, α-Gal TentaGel and α-Gal agarose. The α-Gal HiCore resin developed in this study can be utilized in a wide range of applications including ex vivo immunoadsorption and as a quantitative assay of anti-Gal antibody in human sera.     

Studies on the microbial transformation of androst-1,4-dien-3,17-dione with Acremonium strictum

The strain of Acremonium strictum PTCC 5282 was applied to investigate the biotransformation of androst-1,4-dien-3,17-dione (I; ADD). Microbial products obtained were purified by preparative TLC and the pure metabolites were characterized on the basis of their spectroscopic features (¹³C NMR, ¹H NMR, FTIR, MS) and physical constants (melting points and optical rotations). The 15α-Hydroxyandrost-1,4-dien-3,17-dione (II), 17β-hydroxyandrost-1,4-dien-3-one (III), androst-4-en-3,17-dione (IV; AD), 15α-hydroxyandrost-4-en-3,17-dione (V), 15α,17β-dihydroxyandrost-1,4-dien-3-one (VI) and testosterone (VII) were produced during this fermentation. Formation of the 15α,17β-dihydroxy derivative of ADD is reported for the first time during steroid biotransformation. The bioconversion reactions observed were 1,2-hydrogenation, 15α-hydroxylation and 17-ketone reduction. From the time course profile of this biotransformation, ketone reduction and 1,2-hydrogenation were observed from the first day of fermentation while 15α-hydroxylation occurred from the third day. Optimum concentration of the substrate, which gave the maximum bioconversion efficiency, was 0.5 mg ml⁻¹ in one batch. The highest yield of the microbial products recorded in this work was achieved within the pH range 6.5–7.3 and at the temperature of 27 °C.     

Glycoconjugate histochemistry of the digestive tract of <Emphasis Type="Italic">Triturus carnifex</Emphasis> (Amphibia,Caudata)

Summary In this study, the variety of sugar residues in the gut glycoconjugates of Triturus carnifex (Amphibia, Caudata) are investigated by carbohydrate conventional histochemistry and lectin histochemistry. The oesophageal surface mucous cells contained acidic glycoconjugates, with residues of GalNAc, Gal β1,3 GalNAc and (GlcNAc β1,4) _n oligomers. The gastric surface cells mainly produced neutral glycoproteins with residues of fucose, Gal β1-3 GalNAc, Gal-αGal, and (GlcNAc β1,4) _n oligomers in N- and O-linked glycans, as the glandular mucous neck cells, with residues of mannose/glucose, GalNAc, Gal β1,3 GalNAc, (GlcNAc β1,4) _n oligomers and fucose linked α1,6 or terminal α1,3 or α1,4 in O-linked glycans. The oxynticopeptic tubulo-vesicular system contained neutral glycoproteins with N- and O-linked glycans with residues of Gal-αGal, Gal β1-3 GalNAc and (GlcNAc β1,4) _n oligomers; Fuc linked α1,2 to Gal, α1,3 to GlcNAc in (poly)lactosamine chains and α1,6 to GlcNAc in N-linked glycans. Most of these glycoproteins probably corresponds to the H⁺K⁺-ATPase β-subunit. The intestinal goblet cells contained acidic glycoconjugates, with residues of GalNAc, mannose/ glucose, (GlcNAc β1,4) _n oligomers and fucose linked α1,2 to Gal in O-linked oligosaccharides. The different composition of the mucus in the digestive tracts may be correlated with its different functions. In fact the presence of abundant sulphation of glycoconjugates, mainly in the oesophagus and intestine, probably confers resistance to bacterial enzymatic degradation of the mucus barrier.     

Analysis of sparteines in the seeds of Ammopiptanthus mongolica

Seven alkaloids were isolated from the seeds of Ammopiptanthus mongolica by thin layer chromatography and silica gel column chromatography, and the chemical structures of five alkaloids, 17-oxosparteine, β-isosparteine, 3α-hydroxysparteine, sparteine, and 3β-hydroxysparteine were identified by ¹H nuclear magnetic resonance (NMR) and electron ionization mass spectrum (EIMS). __________ Translated from Journal of Lanzhou University (Natural Sciences), 2007, 43(2): 43–46 [译自: 兰州大学学报(自然科学版)]     

<Emphasis Type="Italic">Pseudomonas aeruginosa</Emphasis> mucoid strain 8830 binds glycans containing the sialyl-Lewis x epitope

Pseudomonas aeruginosa infection of patients with cystic fibrosis (CF) is a leading cause of their morbidity and mortality. Pathogenesis is initiated in part by molecular interactions of P. aeruginosa with carbohydrate residues in airway mucins that accumulate in the lungs of patients with this disease. To explore the nature of the glycans recognized by a stable, mucoid, alginate-producing strain P. aeruginosa 8830 we generated a genetically modified Pa8830 expressing green fluorescent protein (Pa3380-GFP). We tested its binding to a panel of glycolipids and neoglycolipids in which selected glycans were covalently attached to dipalmitoyl phosphatidylethanolamine and analyzed on silica gel surfaces. Among all glycans tested, Pa8830-GFP bound best to sialyl-Le^x-containing glycan NeuAc(α2-3)Gal(β1-4)[Fuc(α1-3)]GlcNAc-R and bound weakly to H-type blood group Fucα1-2Galβ1-4GlcNAc-R, sialyl-lactose, and Le^x, and exhibited little binding toward non-fucosylated derivatives. Interestingly, while Pa8830-GFP bound to the glycosphingolipid asialoGM1, it did not appear to bind to a wide variety of other glycosphingolipids including GM1, GM2, asialoGM2, and sulfatide. These results indicate that P. aeruginosa 8830 has preferential binding to sialyl-Le^x-containing glycans and has weak recognition of related fucose- and sialic acid-containing glycans. The finding that Pa8830 binds sialyl-Le^x-containing glycans, which occur at increased levels in mucins from CF patients, is consistent with studies of other strains of P. aeruginosa and further suggests that such glycans on CF mucins contribute to disease pathogenesis. Invited Submission from Dr. Subhash Basu, from the 7th International Symposium on Biochemical Roles of Eukaryotic Cell Surface Macromolecules in Puri, India, January, 2005.     

Substrate specificity of a recombinant chicken <Emphasis Type="Italic">β</Emphasis>-carotene 15,15′-monooxygenase that converts <Emphasis Type="Italic">β</Emphasis>-carotene into retinal

The recombinant β-carotene 15,15′-monooxygenase from chicken liver was purified as a single 60 kDa band by His-Trap HP and Resource Q chromatography. It had a molecular mass of 240 kDa by gel filtration indicating the native form to be tetramer. The enzyme converted β-carotene under maximal conditions (pH 8.0 and 37°C) with a k _cat of 1.65 min⁻¹ and a K _m of 26 μM and its conversion yield of β-carotene to retinal was 120% (mol mol⁻¹). The enzyme displayed catalytic efficiency and conversion yield for β-carotene, β-cryptoxanthin, β-apo-8′-carotenal, β-apo-4′-carotenal, α-carotene and γ-carotene in decreasing order but not for zeaxanthin, lutein, β-apo-12′-carotenal and lycopene, suggesting that the presence of one unsubstituted β-ionone ring in a substrate with a molecular weight greater than C₃₀ seems to be essential for enzyme activity.     

Core 2 GlcNAc transferase and kidney tubular cell-specific expression

The expression of glycan chains is precisely regulated in a time- and space-dependent manner. We summarize here our recent work on the kidney tubular cell-specific regulation of core 2 β-1,6-GlcNAc transferase. Gsl5 gene was first identified by genetic analysis on the basis of polymorphic expression of kidney glycolipids among inbred strains of mice and turned out to be a regulatory gene controlling the level of mRNA of kidney-specific core 2 β-1,6-GlcNAc transferase. This kidney-specific core 2 GlcNAc transferase takes glycolipids having Galβ1-3GalNAc at their termini, Galβ1-3GalNAcα1- and β1-oligosaccharide derivatives, and glycoproteins having core 1 structure, as substrates. Immunohistochemistry with anti-core 2-Le ^x monoclonal antibody demonstrated that vesicles located just below the microvillous membrane of proximal tubule cells were clearly stained in a Gsl5-wild type mouse. Western blotting with the monoclonal antibody detected a major glycoprotein with a molecular mass of 500 kDa in the microsomal fraction of the wild type mouse kidney. In situ hybridization with anti-sense cDNA of kidney-specific core 2 GlcNAc transferase confirmed that Gsl5 gene controls the expression of the core 2 β-1,6-GlcNAc transferase mRNA in a proximal tubular cell-specific manner. The 5′ upstream sequences of the kidney-specific core 2 GlcNAc transferase gene in inbred and wild-derived strains of mice were analyzed, and the phylogenetic analysis of these sequences suggests that functional Gsl5 gene might be produced by the time of subspeciation of M. musculus, about one million years ago. Published in 2004. This revised version was published online in August 2006 with corrections to the Cover Date.     

Origin and evolution of the sulawesi macaques 1. Electrophoretic analysis of hemoglobins

The monkeys on the island of Sulawesi (Celebes), Indonesia, comprise seven species ofMacaca, that isM. maura, M. tonkeana, M. hecki, M. nigrescens, M. nigra, M. ochreata, andM. brunnescens. Hemoglobins from 248 individuals of these seven species were analyzed by isoelectric focusing electrophoresis (IEFE) and by starch gel electrophoresis in the presence of urea (USGE). Eighteen phenotypes consisting of eight molecular types were identified by IEFE analysis. The speciestonkeana inhabiting the central part of the island revealed 11 phenotypes, while peripheral species such asnigrescens andbrunnescens carried only 3 and 2 phenotypes, respectively. On USGE, three α chains and three β chains were identified and named α1, α2, and α6, and β1, β3, and β5, respectively. The α1 chain has the same mobility as the α chains of other macaques, while the α2 chain is less positively charged than α1, and α6 is the least positive among these α chains. The α2 chain is widely distributed in the Sulawesi macaques as the major component. Four species,ochreata, tonkeana, maura, andnigrescens, carried the α1 and α6 chains as minor components. The electrophoretic mobility of β1 was the same as that of other macaques, while β3 and β5 were more positively charged and less positively charged than β1, respectively. All of the Sulawesi species had β3 in high or low gene frequencies and inmaura, tonkeana, andbrunnescens, this type was most abundant. β5 chain existed in the species of the northern peninsula, as the major type. The subordinate type was β3 innigra andnigrescens and β1 inhecki. On the other hand, β1 was most frequently observed inochreata.     

β-Carotene synthesis in isolated chromoplasts from Narcissus pseudonarcissus

A system has been established from isolated intact chromoplasts of Narcissus pseudonarcissus flowers that synthesizes geranylgeraniol, an unknown polyprenoid alcohol, phytoene, and -carotene from [1-¹⁴C]isopentenyl pyrophosphate in a good yeild. Long chain pyrophosphates are not accumulated. San 6706 inhibits the dehydrogenation of phytoene, whereas nicotine does not lead to an accumulation of lycopene. Separation and identification of polyprenoid lipids was performed by HPLC. The properties and advantages of the chromoplast system are discussed.Abbreviations IPP isopentenyl pyrophosphate - TLC thin-layer chromatography - HPLC high pressure liquid chromatography - GC gas chromatography - Sau 6706 4-chloro-5-(dimethylamino)-2-,,-(trifluoro-m-tolyl)3(2H)-pyridazinone     

Purification,characterization, and potential applications of formate oxidase from <Emphasis Type="Italic">Debaryomyces vanrijiae</Emphasis> MH201

Formate oxidase was found in cell-free extracts of Debaryomyces vanrijiae MH201, a soil isolate. After purification by column chromatography, the preparation showed a protein band corresponding to a molecular mass (MM) of 64 kDa on sodium dodecyl sulfate–polyacrylamide gel electrophoresis. The MM, estimated by a gel filtration, was 99 kDa. The preparation showed two and three bands on isoelectric focusing under denaturing and native conditions, respectively. These results suggest that the preparation contained three isoforms, each of which might be composed of αα, αβ, and ββ subunits with apparently similar MM. The preparation acted on formate with K _m and V _max values of 11.7 mM and 262 μmol min⁻¹ mg⁻¹, respectively, at pH 4.5 and 25°C, but showed no evidence of activity on the other compounds tested. The optimum pH and temperature were pH 4.0 and 35°C, respectively. The preparation showed activities of 85% of the initial activity after storage at pH 6.0 and 4°C for 8 weeks. When 10 mM formaldehyde was reacted with 2.0 U ml⁻¹ of the enzyme preparation at pH 5.5 and room temperature in the presence of 2.0 U ml⁻¹ of a microbial aldehyde oxidase and 100 U ml⁻¹ of catalase for 180 min, neither of formate nor formaldehyde was detected, suggesting that the reaction involved the quantitative conversion of formaldehyde to carbon dioxide.     

Structural characterization and surface-active properties of a new glycolipid biosurfactant,mono-acylated mannosylerythritol lipid,produced from glucose by <Emphasis Type="Italic">Pseudozyma antarctica</Emphasis>

Mannosylerythritol lipids (MELs), which are glycolipid biosurfactants produced by Pseudozyma yeasts, show not only excellent interfacial properties but also versatile biochemical actions. In the course of MEL production from glucose as the sole carbon source, P. antarctica was found to produce unknown glycolipids more hydrophilic than conventional “di-acylated MELs,” which have two fatty acyl esters on the mannose moiety. Based on a detailed characterization, the most hydrophilic one was identified as 4-O-(3′-O-alka(e)noyl-β-d-mannopyranosyl)-d-erythritol namely, “mono-acylated MEL.” The mono-acylated MEL reduced the surface tension of water to 33.8 mN/m at a critical micelle concentration (CMC) of 3.6 × 10⁻⁴ M, and its hydrophilic–lipophilic balance was tentatively calculated to be 12.15. The observed CMC was 100-fold higher than that of the MELs hitherto reported. Interestingly, of the yeast strains of the genus Pseudozyma, only P. antarctica and P. parantarctica gave the mono-acylated MEL from glucose, despite a great diversity of di-acylated MEL producers in the genus. These strains produced MELs including the mono-acylated one at a rate of 20–25%. From these results, the new MEL is likely to have great potential for use in oil-in-water-type emulsifiers and washing detergents because of its higher water solubility compared to conventional MELs and will thus contribute to facilitating a broad range of applications for the environmentally advanced surfactants.     

Structural analysis of cell wall mannan of <Emphasis Type="Italic">Candida sojae</Emphasis>, a new yeast species isolated from defatted soybean flakes

We investigated the structural and immunochemical characteristics of cell wall mannan obtained from Candida sojae JCM 1644, which is a new yeast species isolated from defatted soybean flakes. The results of a slide-agglutination test and of an enzyme-linked immunosorbent assay using anti-factor sera to the pathogenic Candida species indicated that the cells and the C. sojae mannan were cross-reactive to the specific anti-factor sera against Candida albicans serotype A (FAb 6) and Candida guilliermondii (FAb 9). Two-dimensional homonuclear Hartmann–Hahn analysis indicated that the mannan consisted of various linked oligomannosyl side chains containing α-1,2-, α-1,3-, α-1,6- and β-1,2-linked mannose residues. However, although the determinants of antigenic factors 6 and 9 could be not found in this mannan, branched side chains, Manβ1-2Manα1-3[Manα1-6]Manα1-(2Manα1-)n2Man and a linear α-1,6-linked polymannosyl backbone, which are cross-reacted by FAbs 6 and 9, respectively, were identified. The mannan was subjected to acetolysis in order to determine the polymerization length of the α-1,2-linked oligomannosyl residue in the side chains. The result of ¹H-nuclear magnetic resonance analysis of the released oligosaccharides showed that the remarkable regularity in the length of α-1,2-linked oligomannosyl side chains, which were previously found in mannans of other Candida species, is not observed in this mannan.     

Structure of a new nonasaccharide isolated from human milk: VI2Fuc,V4Fuc,III3Fuc-p-lacto-N-hexaose

The structure of a new nonasaccharide isolated from human milk has been investigated. By using methylation analysis, FAB-MS and¹H-and¹³C-NMR spectroscopy as basic methods of structural investigation, this oligosaccharide was identified as VI²--Fuc,V⁴-Fuc,III³--Fuc-p-lacto-n-hexaose: Fuc1-2Gal1-3[Fuc1-4]GlcNAc1-3Gal1-4[Fuc1-3]GlcNAc1-3Gal1-4Glc.Abbreviations COSY correlation spectroscope - DP degree of polymerisation - FAB-MS fast atom bombardment-mass spectrometry - HPLC high performance liquid chromatography - NMR nuclear magnetic resonance - GLC gas-liquid chromatography     

Di-<Emphasis Type="Italic">tert</Emphasis>-butylsilylene-directed α-selective synthesis of <Emphasis Type="Italic">p</Emphasis>-nitrophenyl T-antigen analogues

Seven analogues of p-nitrophenyl T-antigen [Galβ(1→3)GalNAcα(1→O)PNP] have been synthesized as potential substrates for elucidation of the substrate specificity of endo-α-N-acetylgalactosaminidase. These compounds, which are commercially unavailable, include: GlcNAcβ(1→3){GlcNAcβ(1→6)}GalNAcα(1→O)PNP [core 4 type], GalNAcα(1→3)GalNAcα(1→O)PNP [core 5 type], GlcNAcβ(1→6)GalNAcα(1→O)PNP [core 6 type], GalNAcα(1→6)GalNAcα(1→O)PNP [core 7 type], Galα(1→3)GalNAcα(1→O)PNP [core 8 type], Glcβ(1→3)GalNAcα(1→O)PNP and GalNAcβ(1→3)GalNAcα(1→O)PNP. The assembly of these synthetic probes was accomplished efficiently, based on di-tert-butylsilylene(DTBS)-directed α-galactosylation as a key reaction.     

Simultaneous production and characterization of medium-chain-length polyhydroxyalkanoates and alginate oligosaccharides by <Emphasis Type="Italic">Pseudomonas mendocina</Emphasis> NK-01

When Pseudomonas mendocina NK-01 was cultivated in a 200-L fermentor using glucose as carbon source, 0.316 g L⁻¹ medium-chain-length polyhydroxyalkanoate (PHA_MCL) and 0.57 g L⁻¹ alginate oligosaccharides (AO) were obtained at the end of the process. GC/MS was used to characterize the PHA_MCL, which was found to be a polymer mainly consisting of 3HO (3-hydroxyoctanoate) and 3HD (3-hydroxydecanoate). T _m and T _g values for the PHA_MCL were 51.03°C and −41.21°C, respectively, by DSC. Its decomposition temperature was about 300°C. The elongation at break was 700% under 12 MPa stress. MS and GPC were also carried out to characterize the AO which had weight-average molecular weights of 1,546 and 1,029 Da, respectively, for the two main components at the end of the fermentation process. MS analysis revealed that the AO were consisted of β-d-mannuronic acid and/or α-l-guluronic acid, and the β-d-mannuronic acid and/or α-l-guluronic acid residues were partially acetylated at position C2 or C3.