Cell-wall polysaccharides and glycoproteins of parenchymatous tissues of runner bean (Phaseolus coccineus).

1. Polymers were solubilized from the cell walls of parenchyma from mature runner-bean pods with minimum degradation by successive extractions with cyclohexane-trans-1,2-diamine-NNN'N'-tetra-acetate (CDTA), Na2CO3 and KOH to leave the alpha-cellulose residue, which contained cross-linked pectic polysaccharides and Hyp-rich glycoproteins. These were solubilized with chlorite/acetic acid and cellulase. The polymers were fractionated by anion-exchange chromatography, and fractions were subjected to methylation analysis. 2. The pectic polysaccharides differed in their ease of extraction, and a small proportion were highly cross-linked. The bulk of the pectic polysaccharides solubilized by CDTA and Na2CO3 were less branched than those solubilized by KOH. There was good evidence that most of the pectic polysaccharides were not degraded during extraction. 3. The protein-containing fractions included Hyp-rich and Hyp-poor glycoproteins associated with easily extractable pectic polysaccharides, Hyp-rich glycoproteins solubilized with 4M-KOH+borate, the bulk of which were not associated with pectic polysaccharides, and highly cross-linked Hyp-rich glycoproteins. 4. Isodityrosine was not detected, suggesting that it does not have a (major) cross-linking role in these walls. Instead, it is suggested that phenolics, presumably linked to C-5 of 3,5-linked Araf residues of Hyp-rich glycoproteins, serve to cross-link some of the polymers. 5. There were two main types of xyloglucan, with different degrees of branching. The bulk of the less branched xyloglucans were solubilized by more-concentrated alkali. The anomeric configurations of the sugars in one of the highly branched xyloglucans were determined by 13C-n.m.r. spectroscopy. 6. The structural features of the cell-wall polymers and complexes are discussed in relation to the structure of the cell walls of parenchyma tissues.     

Solution properties of targacanthin (water-soluble part of gum tragacanth exudate from Astragalus gossypinus)

Solution properties of tragacanthin (the water-soluble part of gum tragacanth) were studied by gel permeation chromatography (GPC) combined with multi-angle light scattering and viscometry at 25 degrees C. Photon correlation spectroscopy was used to determine the hydrodynamic radius. Ultrasonic degradation was applied to obtain biopolymer fractions of different molecular weights. The dependence of intrinsic viscosity [eta] and radius of gyration (s2)z(1/2) on weight average molecular mass M(w) for this biopolymer were found to be [eta] = 9.077 x 10(-5) M(w)(0.87) (dL g(-1)) and (s2)z(1/2) in the range of M(w) from 1.8 x 10(5) to 1.6 x 10(6). The conformational parameters of tragacanthin were calculated to be 1111 nm for molar mass per unit contour length (M(L)), 26 nm for persistence length (q) and 1.87 ratio of R(g)/R(h). It was found that the Smidsr?d parameter B, the empirical stiffness parameter was 0.013, which is lower than that of several polysaccharides indicating the stiff backbone for tragacanthin. The rheological behavior of aqueous solutions of gum tragacanth and its insoluble and soluble fractions (bassorin and tragacanthin, respectively) were studied. For concentrations equal to 1%, at 25 degrees C and in the absence of salt, bassorin solution showed the highest viscosity and shear thinning behaviour. Power law and Williamson models were used to describe the rheological behaviour of bassorin and tragacanthin, respectively. Oscillatory shear experiments showed a gel like structure for the bassorin but for tragacanthin the oscillatory data were as would be expected for semi-dilute to concentrated solution of entangled, random coil polymers. NaCl changed the steady and oscillatory rheological properties of both fractions and in this way the final viscosity of bassorin was even less than tragacanthin. The calculated activation energy for bassorin and tragacanthin indicated a more rapid decrease in viscosity with temperature for tragacanthin. The plot of eta(sp,0) versus C[eta] revealed that the transition from dilute to semi-dilute regime occurs at C*[eta] = 2.82 for tragacanthin.     

Optimization of glycosidases production by Pseudoalteromonas issachenkonii KMM 3549(T)

AIMS: The present work aimed to design an optimized medium to yield a higher production of glycosides by Pseudoalteromonas issachenkonii KMM 3549(T). METHODS AND RESULTS: Higher levels of fucoidan hydrolase, alginase, laminaranase and b-N-acetylglucosaminidase production were obtained with peptone concentrations ranging from 2.5 g l(-1) to 10 g l(-1), while the presence of both yeast extract and glucose did not affect enzyme production. The activity of fucoidan hydrolase and laminaranase increased up to 4.83 microM h(-1) mg(-1) and 19.23 microM h(-1) mg(-1) protein, respectively, in growth media containing xylose (1.0 g l(-1)), laminarin (0.5 g l(-1)) or alginate (0.5 g l(-1)), and production of b-N-acetylglucosaminidase substantially increased in the presence of fucoidan (0.5 g l(-1)) or galactose (1 g l(-1)). All polysaccharides tested in concentrations of 0.5 g l(-1) fucoidan and 0.2 g l(-1) fucose induced production of alginase (up to 5.06 microM h(-1) mg-1 protein). CONCLUSIONS: The production of glycosidases is not only stimulated by the presence of algal polysaccharides, but may also be stimulated by monosaccharides (e.g. xylose). SIGNIFICANCE AND IMPACT OF THE STUDY: The production of glycosidases by Pseudoalteromonas issachenkonii KMM 3549(T) was significantly improved by using a simple nutrient medium containing peptone (2.5 g l(-1)) and xylose (5.0 g l(-1)) in 100% natural seawater.     

Structural features of pectic polysaccharides from the skin of Opuntia ficus-indica prickly pear fruits

After removal of the mucilage with water at room temperature, pectic polysaccharides were solubilized from Opuntia ficus-indica fruit skin, by sequential extraction with water at 60 degrees C (WSP) and EDTA solution at 60 degrees C (CSP). Polysaccharides with neutral sugar content of 0.48 and 0.36 mol/mol galacturonic acid residue were obtained, respectively, in the WSP and CSP extracts. These pectic polysaccharides were de-esterified and fractionated by anion-exchange chromatography, yielding for each extract five fractions, which were thereafter purified by size-exclusion chromatography. Two of these purified fractions were characterized by sugar analysis combined with methylation and reduction-methylation analysis. The study was then supported by (1)H and (13)C NMR spectroscopy. The results showed that the water-soluble fraction WSP3 and the EDTA soluble fraction CSP3, consisted of a disaccharide repeating unit -->2)-alpha-l-Rhap-(1-->4)-alpha-d-GalpA-(1--> backbone, with side chains attached to O-4 of the rhamnosyl residues. The side chains contained highly branched alpha-(1-->5)-linked arabinan and short linear beta-(1-->4)-linked galactan.     

Solid-state 13C-NMR spectroscopy shows that the xyloglucans in the primary cell walls of mung bean (Vigna radiata L.) occur in different domains: a new model for xyloglucan-cellulose interactions in the cell wall

Xyloglucans (XG) with different mobilities were identified in the primary cell walls of mung beans (Vigna radiata L.) by solid-state 13C-NMR spectroscopy. To improve the signal:noise ratios compared with unlabelled controls, Glc labelled at either C-1 or C-4 with 13C-isotope was incorporated into the cell-wall polysaccharides of mung bean hypocotyls. Using cell walls from seedlings labelled with d-[1-13C]glucose and, by exploiting the differences in rotating-frame and spin-spin proton relaxation, a small signal was detected which was assigned to Xyl of XGs with rigid glucan backbones. After labelling seedlings with d-[4-13C]glucose and using a novel combination of spin-echo spectroscopy with proton spin relaxation-editing, signals were detected that had 13C-spin relaxations and chemical shifts which were assigned to partly-rigid XGs surrounded by mobile non-cellulosic polysaccharides. Although quantification of these two mobility types of XG was difficult, the results indicated that the partly-rigid XGs were predominant in the cell walls. The results lend support to the postulated new cell-wall models in which only a small proportion of the total surface area of the cellulose microfibrils has XG adsorbed on to it. In these new models, the partly-rigid XGs form cross-links between adjacent cellulose microfibrils and/or between cellulose microfibrils and other non-cellulosic polysaccharides, such as pectic polysaccharides.     

不同品种苹果采后后熟软化过程中细胞壁多糖的降解

以2种苹果为试材,提取了不同贮藏时期果实的细胞壁物质和8种细胞壁多糖组分,并采用气相色谱法分析了细胞壁多糖组分的单糖组成。结果表明,在贮藏过程中,‘金星’苹果果肉的硬度下降明显,在贮藏第10天前后出现明显的乙烯释放量高峰,而耐贮藏性‘富士’苹果在贮藏期间只释放极少量的乙烯。‘金星’苹果的Na2CO3-1溶性果胶多糖组分的减少尤为显著。这些结果表明,苹果果实Na2CO3-1溶性果胶多糖组分侧链成分的酶降解,是引起苹果细胞壁多糖网络结构的变化,进而导致果实软化的重要原因之一。     

Composition of the cell walls of different asparagus (Asparagus officinalis) tissues

Portions of stems from the base of asparagus spears (Asparagus officinalis L. cv. Connovor Collossus) were dissected to give the following tissues: (1) pith, which was free of vascular bundles, (2) two surrounding layers, parenchyma and fibre I and II (PFI and PFII), containing parenchyma and vascular bundles, (3) sclerenchyma sheath, (4) epidermis and sub-epidermal layers and (5) asparagus vascular fibre (AVF). The alcohol-insoluble residues (AIRs) from these tissues were shown to be free of starch. They were analysed for moisture and protein, and the component sugars were released by two hydrolytic procedures, which helped to distinguish the sugars from non-cellulosic polysaccharides and cellulose. The AIRs from pith and epidermal tissues were relatively low in xylose, but were rich in cellulosic glucose, and sugars associated with pectic polysaccharides such as galacturonic acid, galactose and arabinose. Their major component polysaccharides (in decreasing amounts) were inferred to be pectic polysaccharides, cellulose, and hemicelluloses. AIR from sclerenchyma was rich in glucose and xylose, suggesting the presence of much cellulose and (acidic) xylans. The AIRs of PFI, PFII and AVF contained significant amounts of xylose in addition tn other sugars, and the major polysaccharides inferred to be present were pectic polysaccharides, cellulose and hemicelluloses, a significant proportion of which may be acidic xylans. Methylation analysis of the AIRs confirmed the above inferences. The bulk of the glucosyl residues were (1–4)-linked, and there were small but significant amounts of (1–4, 6)-linked glucosyl residues (the linkage characteristic of xyloglucans) in all the preparations. The presence of (1–4)-linked galactosyl, (1–5)-linked arabinosyl, terminal galactosyl, terminal arabinosyl, (1–2)- and (1–2, 4)-linked rhamnosyl residues in all the AIRs except that from sclerenchyma, confirmed the presence of significant levels of pectic polysaccharides in all the parenchyma tissues. All the preparations containing vascular tissues contained significant amounts of (1–4)-linked xylosyl residues, probably derived from acidic xylans. Even in the AIR of pith, a significant amount of (1–4)-linked xylosyl residues were detected. This may be due to the ability of these cells and the parenchyma cells associated with the vascular bundles, to undergo lignification in mature asparagus plants.     

Cell wall changes in immature Asparagus stem tissue after excision.

Cell wall material (CWM) was prepared from sections of fresh and aerobically-stored asparagus (Asparagus officinalis, L. cv. Connovor Collossus) stems. Polymers were solubilized from the CWM by successive extraction with cyclohexane-trans-1,2-diamine-N N N' N'-tetraacetate (CDTA), Na2CO3 and KOH to leave the alpha-cellulose residue which contained a significant amount of cross-linked pectic polysaccharides. The polymers were fractionated by anion-exchange chromatography and selected fractions were subjected to methylation analysis. The storage-related decrease in (1-4)-linked Galp was detected in all the fractions rich in pectic polysaccharides, particularly in the CDTA, Na2CO3, 0.5 M KOH fractions and alpha-cellulose residue. A smaller decrease in Araf was also observed. This was mainly due to a decrease in (1-5)-linked Araf in the Na2CO3-1-soluble polymers, and terminal Araf in the alpha-cellulose residue. There was evidence for the occurrence of significant amounts of complexes containing pectic polysaccharides and xylans having a relatively low degree of polymerization in the dilute alkali-soluble polymers, and some of these contained phenolic compounds; the storage-induced increase in (1-4)-linked Xylp was confined to these polymers. Interestingly, no free acidic xylans could be detected in the 1 M and 4 M KOH-soluble polymers; instead, the bulk of the hemicellulosic polysaccharides appeared to be mixtures of xyloglucans and xylans in which the ratio of xyloglucan to xylan increased with increasing strength of alkali used for extraction of the polymers. The non-degradative extraction and fractionation procedures revealed heterogeneity in pectic polysaccharides, pectic polysaccharide-xylan complexes and xyloglucans in close association with xylans. The possible relationship between pectic polysaccharide-xylan-phenolic complexes and the onset of lignification in maturing tissues is discussed.     

Polysaccharide compositions of primary cell walls of the palms Phoenix canariensis and Rhopalostylis sapida

The polysaccharide compositions of unlignified primary cell walls from two species of palms were examined. Cell-wall preparations were isolated from the stem apex, including the pre-emergent leaflets and rachides, of Phoenix canariensis (Canary Island date palm), and from leaflets and rachides dissected from pre-emergent leaves in the stem apex of Rhopalostylis sapida (Nikau palm). The non-cellulosic polysaccharides in the cell-wall preparations from both species had similar monosaccharide compositions, with arabinose and galactose being the predominant neutral monosaccharides, together with large amounts of galacturonic acid. These monosaccharide compositions indicated the presence of large proportions of pectic polysaccharides, including homogalacturonans. This was confirmed by linkage analyses of the cell-wall preparations which showed the presence of large proportions of pectic arabinans, together with pectic galactans and/or Type I arabinogalactans. Evidence for rhamnogalacturonan I and small amounts of rhamnogalacturonan II was also obtained. In addition to pectic polysaccharides, the cell-wall preparations contained smaller amounts of xyloglucans and even smaller amounts of heteroxylans, probably glucuronoarabinoxylans, and glucomannans and/or galactoglucomannans; (1→3,1→4)-β-D-glucans were not present. Although palms (Arecaceae) are commelinoid monocotyledons, the polysaccharide compositions of their primary cell walls resemble those of non-commelinoid monocotyledons and dicotyledons. These compositions contrast with those of primary cell walls of other commelinoid families which have glucuronoarabinoxylans rather than pectic polysaccharides as the major non-cellulosic polysaccharides. The results are discussed in relation to the possible evolution of the composition of primary cell walls of monocotyledons.     

Labeling and chemistry of grapefruit pectic substances

The labeling of a number of polysaccharides found in grapefruit (Citrus paradisi) was achieved by feeding labeled myo-inositol to ripening grapefruit through their cut fruit stem, and allowing 4 days for the metabolism of label. The pectic polysaccharides were isolated by successive extraction of the labeled grapefruit with 80% ethanol, chloroform-methanol (1:1) and finally with 0.2 M Na₂ EDTA to solubilize pectic polysaccharides. The incorporation of label from myo-inositol into galacturonosyl, arabinosyl, xylosyl and galactosyl residues of pectic polysaccharides via myo-inositol oxidation pathway was demonstrated. Ion exchange chromatography of these labeled pectic polysaccharides using DE-52 cellulose resulted in the elution of eight totally or partially resolved polysaccharides with increasing salt concentration. The results suggest that, like other plant tissues, the myo-inositol oxidation pathway is also operative in ripening grapefruit and this metabolic pathway could be successfully utilized to achieve labeling of a number of pectic polysaccharides.     

The presence of natural human antibodies reactive against pharmacologically active pectic polysaccharides from herbal medicines

Direct ELISA was performed using normal human sera and human colostrum, to analyse the presence of antibodies which react with pharmacologically active pectic polysaccharides isolated from plants used in traditional Japanese herbal (Kampo) medicine. All sera and colostrum were shown to contain IgM, IgG, IgA and secretory IgA class antibodies which react with the active pectic polysaccharides to different degrees. The reacting IgG antibody in normal human serum recognized the ramified regions (rhamnogalacturonan core with carbohydrate side-chains) of the pharmacologically active pectic polysaccharides as the active sites for complement-activating activity. Correlation analysis indicated that a significant and positive correlation was observed between reactivity with the reacting antibody of IgG class and the degree of complement-activating activity of the active polysaccharides.The reacting IgG class antibody, which was purified from normal human serum by affinity chromatography on bupleuran 2IIc (a pharmacologically active pectic polysaccharide from the roots of Bupleurum falcatum)-immobilized Sepharose, showed cross-reactivity not only with some other pharmacologically active pectic polysaccharides from other medicinal herbs but also with autoantigens such as single-strand DNA, myosin and tublin from mammals.     

Application of CP-MAS and liquid-like solid-state NMR experiments for the study of the ripening-associated cell wall changes in tomato

¹³C and ¹H NMR spectra of an ethanol insoluble material (EIM) prepared from the pericarp of mature-green (MG) and red-ripe (RR) tomato fruits were acquired in ‘liquid-like’ and cross-polarisation with dipolar decoupling and magic angle spinning (CPMAS) conditions using the same triple resonance probe. Such a strategy allowed acquisitions of various NMR experiments aimed at detecting compositional differences as well as distinguishing differences in molecular mobility for various constituent polysaccharides related with the two ripening stages. Increase of the proton dipolar decoupling power levels from 3 to 50–55 kHz during single pulse ¹³C acquisition, led to more intense signals for pectic and hemicellulosic polysaccharides. This behaviour was interpreted as reflecting motional restrictions of these polysaccharides inside the porous cell wall network. Measurements of the proton rotating frame relaxation times T_1ρ in the ‘liquid-like’ conditions and of the proton transverse relaxation times T₂ from CPMAS spectra, revealed changes in mobilities for some pectic polysaccharides in relation with ripening, particularly for the H1 and H5 protons of -1,5 arabinan (Ara) side chains of rhamnogalacturonans. These data are discussed in relation with known pectic modifications occurring during ripening and associated with the tomato fruit softening.     

Exopolysaccharide production by Streptococcus thermophilus SY: production and preliminary characterization of the polymer

AIMS: To evaluate the effect of yeast extract (YE) concentration, temperature and pH on growth and exopolysaccharide (EPS) production in a whey-based medium by Streptococcus thermophilus SY and to characterize the partially purified EPS. METHODS AND RESULTS: Factorial experiments and empirical model building were used to optimize fermentation conditions and the chemical composition, average molecular weight (MW) and rheological properties of aqueous dispersions of the EPS were determined. Exopolysaccharide production was growth associated and was higher (152 mg l(-1)) at pH 6.4 and 36 degrees C with 4 g l(-1) YE. High performance size exclusion chromatography of the partially purified EPS showed two peaks, with a weight average MW of 2 x 10(6) and 5 x 10(4), respectively. The EPS was a heteropolysaccharide, with a glucose : galactose : rhamnose ratio of 2 : 4.5 : 1. Its water dispersions had a pseudoplastic behaviour and showed a higher viscosity of xanthan solutions. SIGNIFICANCE AND IMPACT OF THE STUDY: The fermentation conditions and some properties of an EPS produced by Strep. thermophilus, a dairy starter organism, were described.     

Boron and calcium, essential inorganic constituents of pectic polysaccharides in higher plant cell walls

Among 16 essential elements of higher plants, Ca²⁺ and B have been termed as apoplastic elements. This is mainly because of their localization in cell walls, however, it has turned to be highly likely that these two elements significantly contribute to maintain the integrity of cell walls through binding to pectic polysaccharides. Boron in cell walls exclusively forms a complex with rhamnogalacturonan II (RG-II), and the B-RG-II complex is ubiquitous in higher plants. Analysis of the structure of the B-RG-II complex revealed that the complex contains two molecules boric acid, two molecules Ca²⁺ and two chains of monomeric RG-II. This result indicates that pectic chains are cross-linked covalently with boric acid at their RG-II regions. The complex was reconstitutedin vitro only by mixing monomeric RG-II and boric acid, however, the complex decomposed spontaneously unless Ca²⁺ was supplemented. Furthermore, the native complex decomposed when it was incubated withtrans-1,2-diaminocyclohexane-N, N, N′, N′-tetraacetic acid (CDTA) which chelates Ca²⁺. When radish root cell walls were washed with a buffered 1.5% (w/v) sodium dodesyl sulfate (SDS) solution (pH 6.5), 96%, 13% and 6% of Ca²⁺, B and pectic polysaccharides of the cell walls, respectively, were released and the cell wall swelled twice. Subsequent extraction with 50 mM CDTA (pH 6.5) of the SDS-washed cell walls further released 4%, 80% and 61% of Ca²⁺, B and pectic polysaccharides, respectively. Pectinase hydrolysis of the SDS-treated cell walls yielded a B-RG-II complex and almost all the remaining Ca²⁺ was recovered in the complex. This result suggests that cell-wall bound Ca²⁺ is divided into at least two fractions, one anchors the CDTA-soluble pectic polysaccharides into cell walls together with B, and the other may control the properties of the pectic gel. These studies demonstrate that B functions to retain CDTA-soluble pectic polysaccharides in cell walls through its binding to the RG-II regions in collaboration with Ca²⁺.     

Glucuronoxylomannan of Cryptococcus neoformans serotype B: structural analysis by gas-liquid chromatography-mass spectrometry and 13C-nuclear magnetic resonance spectroscopy.

The major extracellular polysaccharide (glucuronoxylomannan, GXM) from six strains of Cryptococcus neoformans serotype B was characterized by gas-liquid chromatography (g.l.c.), g.l.c.-mass spectrometry (g.l.c.-m.s.), and nuclear magnetic resonance (n.m.r.) spectroscopy. Ultrasonic irradiation (u.i.) was used to reduce the mol.wt. of native GXM from 9.75 x 10(5) to 1.15 x 10(5) without apparent change in its composition (GXM-S). The Xylp:Manp:GlcpA molar ratio of the GXM and GXM-S from the six strains of C. neoformans serotype B is approximately 3.5:3.0:0.6. GXM-S was O-deacetylated (GXM-D) by treatment with NH4OH. The 13C-n.m.r. analysis of GXM-D gave spectra that served as characteristic fingerprints of the structure and also facilitated the assignment of the anomeric carbon resonances to specific structural moieties present in GXM-D. The GXM-D from each serotype B strain was found to be similar by 13C-n.m.r. spectroscopy. The structure contains a linear (1----3)-alpha-D-Manp backbone substituted with 2-O-beta-GlcpA and 2-O-beta-Xylp. beta-Xylp is also O-4 linked to the Manp substituted with GlcpA. In addition, a model for the disposition of the Xylp and GlcpA side chain substituents along the mannopyranan backbone is proposed, based upon results from the combination of g.l.c.-m.s. and 13C-n.m.r. spectroscopy.     

Real-time assessment of postprandial fat storage in liver and skeletal muscle in health and type 2 diabetes

Liver and skeletal muscle triglyceride stores are elevated in type 2 diabetes and correlate with insulin resistance. As postprandial handling of dietary fat may be a critical determinant of tissue triglyceride levels, we quantified postprandial fat storage in normal and type 2 diabetes subjects. Healthy volunteers (n = 8) and diet-controlled type 2 diabetes subjects (n = 12) were studied using a novel 13C magnetic resonance spectroscopy protocol to measure the postprandial increment in liver and skeletal muscle triglyceride following ingestion of 13C-labeled fatty acids given with a standard mixed meal. The postprandial increment in hepatic triglyceride was rapid in both groups (peak increment controls: +7.3 +/- 1.5 mmol/l at 6 h, P = 0.002; peak increment diabetics: +10.8 +/- 3.4 mmol/l at 4 h, P = 0.009). The mean postprandial incremental AUC of hepatic 13C enrichment between the first and second meals (0 and 4 h) was significantly higher in the diabetes group (6.1 +/- 1.4 vs. 1.7 +/- 0.6 mmol x l(-1) x h(-1), P = 0.019). Postprandial increment in skeletal muscle triglyceride in the control group was small compared with the diabetic group, the mean 24-h postprandial incremental AUC being 0.2 +/- 0.3 vs. 1.7 +/- 0.4 mmol x l(-1) x h(-1) (P = 0.009). We conclude that the postprandial uptake of fatty acids by liver and skeletal muscle is increased in type 2 diabetes and may underlie the elevated tissue triglyceride stores and consequent insulin resistance.     

Structural and serological relatedness of the O-antigens of Proteus penneri 1 and 4 from a novel Proteus serogroup O72.

O-specific polysaccharides (O-antigens) of the lipopolysaccharides (LPS) of Proteus penneri strains 1 and 4 were studied using sugar analysis, (1)H and (13)C NMR spectroscopy, including 2D COSY, H-detected (1)H,(13)C HMQC, and rotating-frame NOE spectroscopy (ROESY). The following structures of the tetrasaccharide (strain 1) and pentasaccharide (strain 4) repeating units of the polysaccharides were established: [reaction: see text]. In the polysaccharide of P. penneri strain 4, glycosylation with the lateral Glc residue (75%) and O-acetylation of the lateral GalNAc residue (55%) are nonstoichiometric. This polysaccharide contains also other, minor O-acetyl groups, whose positions were not determined. The structural similarity of the O-specific polysaccharides was consistent with the close serological relatedness of the LPS, which was demonstrated by immunochemical studies with O-antisera against P. penneri 1 and 4. Based on these data, it was proposed to classify P. penneri strains 1 and 4 into a new Proteus serogroup, O72, as two subgroups, O72a and O72a,b, respectively. Serological cross-reactivity of P. penneri 1 O-antiserum with the LPS of P. penneri 40 and 41 was substantiated by the presence of an epitope(s) on the LPS core region shared by all P. penneri strains studied.     

Extracellular polysaccharides of Erwinia futululu,a bacterium associated with a fungal canker disease of Eucalyptus spp

Extracellular polysaccharides (EPSs) produced by an Erwinia spp. associated with a fungal canker disease of Eucalyptus were fractionated into two polysaccharides, one that was identified with that produced by Erwinia stewartii. The other has a similar structure, but with one terminal Glc residue replaced by pyruvic acid to give 4,6-O-[(R)-1-carboxyethylidene)-Galp. Their structures were determined using a combination of chemical and physical techniques including methylation analysis, periodate oxidation, low-pressure gel filtration and anion-exchange chromatographies, high-pH anion-exchange chromatography, mass spectrometry and 1D and 2D 1H NMR spectroscopy. The new polysaccharides, identified as EPS Futululu FF-1 and FF-2, have the following structures:The molecular weights of the polysaccharides range from 1.3-2.1x10(6) and their hydrodynamic properties are those of polydisperse, polyanionic biopolymers with pseudoplastic, non-thixotropic flow characteristics in aqueous solutions.     

Auxin synthesis by the higher fungus Lentinus edodes (Berk.) Sing in the presence of low concentrations of indole compounds

The auxin formation in a submerged culture of the xylotrophic basidiomycete Lentinus edodes (Berk.) Sing (Lentinula edodes (Berk.) Pegler) (shiitake) is studied. Biologically active substances of an indole nature are identified, "the effect of small doses" of which lies in not only the stimulation of growth of the mycelium (indole-3-acetic acid, 2 x 10(-7)-2 x 10(-4) g/l), but also in the induction of tryptophan-independent paths of auxin biosynthesis. The above-mentioned path is realized in the presence of exogenous indole (1 x 10(-3)-1 x 10(-4) g/l), as well as while inducing the biosynthesis of indole-3-acetic acid by its microadditives (1 x 10(-5)-1 x 10(-8) g/l), and is accompanied by the formation of anthranilic acid (up to 1.5 mg/l). Induction of the generative development stage ofshiitake by indole derivatives is revealed. It was found that among the studied compounds only indoleacetamide at a concentration of an order of x 10(-4) g/l in the culture fluid of L. edodes had a pronounced stimulatory effect on the formation of shiitake's brown mycelial film.     

Autolysis-Iike Release of Pectic Polysaccharides from Regions of Cell Walls Other Than the Middle Lamella

Cell walls of a storage organ (potato tubers) showed autolysis-likeactivity. After 20 h of incubation in water at 35°C, thepurified cell walls released approximately 10% of the cell walldry weight as pectic polysaccharides containing about 40% ofthe total galacturonic acid present in the cell walls. Virtuallyno neutral polysaccharides were found in the soluble fraction.The pectic polysaccharides were heterogeneous in galacturonicacid content and had a very large molecular size. The releaseof pectic polymers was caused neither by enzymatic reactionsnor by ß-elimination, but by a chelation of Ca²⁺ and/orother metal ions during the cell wall isolation. Ultrastructuralobservations clearly showed that these pectic polysaccharideswere released not from the middle lamella, but from the primarycell wall adjacent to the plasma membrane. These results indicatethat nearly half of cell wall pectic polysaccharides are heldin the primary wall only by Ca²⁺- and/or other metal-bridgesand that these pectic polymers are not associated with the middlelamella. (Received March 20, 1989; Accepted October 3, 1989)