Effect of periodate oxidation on the polysaccharide content and microaggregate stability of rhizosphere and non-rhizosphere soils

Summary The relationship between the stability of soil microaggregates in water and the polysaccharide content was examined in rhizosphere and non-rhizosphere samples from a pot experiment using three soils that had grown peas, barley or grasses. The polysaccharide was oxidised and removed using 168h treatment with 0.02M periodate followed by 6h with 0.1M tetraborate. The decrease in polysaccharide content, measured as change in residual reducing sugars, was compared with the stability of soil microaggregates (ca 45m) in water, determined by a turbidimetric method.Total C, N and polysaccharide contents of rhizosphere soils were greater than those for the bulk soil, but the water stability of aggregates was not increased compared to unplanted controls. Periodate oxidation removed a large proportion (59–95%) of the polysaccharide and increased aggregated disruption, but there was no clear relationship between the two measurements. In rhizosphere soil, polysaccharides appreared to make less contribution to aggregate stability than polysaccharide in the bulk soil. The relatively small effect of rhizosphere polysaccharides is probably related to their presence as comparatively massive plant remains and debris; this contrasts with the decomposed and transformed material in the bulk soil.     

The `Lorenzan sulphates'': A new group of vertebrate mucopolysaccharides

1. The mucopolysaccharide from the glands of Lorenzini of Squalus acanthias has been isolated and purified. 2. The material is a sulphated polysaccharide containing glucosamine, galactosamine, galactose and traces of an uronic acid. 3. This vertebrate polysaccharide is unusual in appearing to have both amino sugars present in the molecule. The amino sugars are N-acetylated. 4. This molecule is one of a group of related mucopolysaccharides which vary in composition with the animal species. The generic name ;lorenzan sulphates' is suggested to describe these substances.     

COCCOLITH-ASSOCIATED POLYSACCHARIDES FROM CELLS OF EMILIANIA HUXLEYI (HAPTOPHYCEAE)1

Coccoliths of Emiliania huxleyi (Lohmann) Hay and Mohler, a unicellular calcifying alga, consist of calcite closely associated with an acidic, Ca²⁺-binding polysaccharide. This polysaccharide is thought to play a regulatory role in coccolith synthesis by interfering with CaCO₃ crystallization. Here we show that the polysaccharides from three different strains, A 92, L and 92 D, all inhibit the precipitation of CaCO₃ in vitro to the same extent. The monosaccharide compositions of the A 92 and L polysaccharide are similar. The 92 D material, however, deviates from the other two: it contains significantly lower amounts of methylated sugars and ribose, and elevated levels of rhamnose and galactose. It also contains antigenic determinants not detected in the A 92 and L polysaccharides. In contrast to the latter two macromolecules the 92 D polysaccharide migrates as two bands upon polyacrylamide gel electrophoresis, possibly resulting from complexing with small amounts of protein. The coccolith polysaccharide from L cells, cultured at an elevated growth rate, also migrates as two bands. This phenomenon is due to an increase in molecular size distribution. The results suggest that certain properties of the molecule may be subject to variation without interfering with its function.     

Capsular and extracellular polysaccharides of the diazotrophic rhizobacterium <Emphasis Type="Italic">Herbaspirillum seropedicae</Emphasis> Z78

The diazotrophic endophyte Herbaspirillum seropedicae Z78 was shown to possess a capsule containing two high-molecular-weight glycolipids, one of which was of a lipopolysaccharide nature. These glycolipids differed considerably in the fatty acid composition of their lipid components. The polysaccharide moiety of these glycans was composed of glucose, galactose, glucosamine, galactosamine, and a noncarbohydrate component, butanetetraol. In the culture liquid of H. seropedicae Z78, an extracellular polysaccharide and an extracellular form of lipopolysaccharide were revealed. Fatty acid composition of the extracellular lipopolysaccharide differed from that of the capsular glycoconjugates; the polysaccharide moiety of exoglycans contained only neutral sugars (mannose, glucose, and galactose) and a tetraatomic alcohol, butanetetraol. It is assumed that structural diversity of polysaccharide-containing polymers at the surface of H. seropedicae Z78 cells is conditioned by their different roles in plant colonization and formation of efficient symbiosis.     

A note on the formation of microbial polysaccharide from wheat straw decomposed in the absence of soil

C hapman , S.J. & L ynch , J.M. 1984. A note on the formation of microbial polysaccharide from wheat straw decomposed in the absence of soil. Journal of Applied Bacteriology 56 , 337–342.
The proportions of neutral sugars in fresh and decomposed wheat straw polysaccharide were similar, irrespective of the oxygen concentration used during breakdown. Polysaccharide extracted by hot water from the decomposed straw was composed mainly of galactose, glucose and mannose with smaller quantities of arabinose, xylose, rhamnose, fucose and ribose. The presence of these sugars indicates a mainly microbial origin for the polysaccharide but with some soluble hemi-cellulose breakdown products. The polysaccharide precipitable with 70% (v/v) ethanol accounted for 0.5% (w/w) of the degraded straw. The extracted polysaccharide was shown to increase the aggregate stability of Mount St Helens volcanic ash.     

An alkali-soluble polysaccharide from the cell walls of Coprinus lagopus

An alkali-soluble polysaccharide was isolated from the purified mycelial walls of Coprinus lagopus. The hydrolysis products, optical rotation, and infrared spectrum indicate a -glucan. Hydrolysis of the glucan after permethylation gave only 2,3,4,6-tetra-, 2,4,6-tri-, and 2,4-di-O-methyl-d-glucose. These methylated sugars and their relative quantities reveal that the glucan is a polysaccharide containing -1,3-linked glucose units with about 14% of the sugars having 1,6-linked branch points. Partial hydrolysis of the product derived from Smith degradation of the glucan released laminaribiose and gentiobiose suggesting that the branches are generally longer than a single glucose unit.Adapted from a portion of a dissertation submitted in partial fullfillment of the requirements for the Ph.D. degree in botany at the University of Connecticut under the direction of Dr. Ralph P. Collins     

Mucilage from a fresh-water red alga of the genus Batrachospermum

The gelatinous polysaccharides of a Batrachospermum species have been extracted from the alga. The major polysaccharide is acidic and has been separated from neutral polysaccharides by chromatography on DEAE-cellulose. The constituent sugars of the acidic polysaccharide include d- and l-galactose, d-mannose, d-xylose, l-rhamnose, d-glucuronic acid, and two O-methyl sugars, which have been characterized as 3-O-methyl-l-rhamnose (l-acofriose and 3-O-methyl-d-galactose. Partial acid hydrolysis of this polysaccharide has given a complex mixture of neutral and acidic oligosaccharides. The two preponderant acidic oligosaccharides contained galactose and glucuronic acid in 1:1 ratio, suggesting the presence of a repeating sequence of these two residues as a major structural feature of the polysaccharide.     

Methylation studies of the polysaccharides resulting from sequential Smith-degradations of the galactan from the snail strophocheilus oblongus

When the galactan from the albumen glands of the snail Strophocheilus oblongus was submitted to three Smith-degradations, the degraded polysaccharide, isolated in 6% yield, was much more linear. Methylation analysis showed that the Smith-degraded polysaccharide gave an increased percentage of 2,4,6-tri-, decreased percentages of 2,3,4,6-tetra- and 2,4-di-, and a large variation in the amount of 2,3,4-tri-O-methyl-d-galactose. The sugars in the polysaccharide which result in the formation of 2,3,4,6-tetra- and 2,3,4-tri-O-methyl-d-galactose are destroyed in subsequent degradation procedures. The above observations suggest that the degradation by periodate oxidation proceeds via non-reducing end-groups and through some internal residues that are exposed as the degradation proceeds. As a result of the overall process, new non-reducing end-groups are formed and new (1 → 6)-linked d-galactose residues are then exposed. The isolation of glycosides of low molecular weight supports the suggestion that the molecule, in the main, is sequentially degraded from the external layers.     

Characterization of lipophorin from Antheraea mylitta drury (Lepidoptera: Saturniidae)

The high molecular weight (680 KDa) glycolipoprotein from the haemolymph of male larvae of Antheraea mylitta Drury (Lepidoptera: Saturniidae) was identified as lipophorin by gradient KBr ultracentrifugation and SDS-PAGE. This lipophorin is composed of two subunits: apolipoprotein 1 (234 KDa) and apoprotein II (80 KDa). The density of the native molecule is 1.1941 g/ml. By weight, it contains 53.7% protein, 3.7% carbohydrate, and 42.6% lipid. Neutral lipids and phospholipids are 66.2 and 33.8% of the total lipids, respectively. Mannose and N-acetylglucosamine are the only sugars detected by gas liquid chromatography. The amino acid composition of both the native molecule and its two subunits was determined, and yielded similar amino acid compositions. © 1996 Wiley-Liss, Inc.     

The production and release of an extracellular polysaccharide during starvation of a marine Pseudomonas sp. and the effect thereof on adhesion

A marine Pseudomonas sp. S9 produced and released an extracellular polysaccharide during complete energy and nutrient starvation in static conditions. The presence of the polysaccharide on the cell surface, demonstrable by immune transmission electron microscopy, correlated with changes in the degree of adhesion to hydrophobic surfaces. Polysaccharide coated cells showed a lower degree of adhesion than did cells devoid of the polymer. After 10 h of starvation, no ruthenium red stained antibody stabilized polysaccharides could be observed on the cell surface. The polysaccharide was not produced during growth since lysates of mid-log phase cells did not precipitate the antiserum. The relative proportions of sugars in the polysaccharide were 28% glucose, 35% N-acetylglucosamine and 37% N-acetylgalactosamine. The released polysaccharide did not significantly alter the physical parameters of surface tension and viscosity of the starvation regime. Cells starved in agitated conditions did not produce any extracellular polysaccharides and exhibited a different adhesion pattern to hydrophobic surfaces.Non-standard abbreviations FSS Four salt solution - GLC gas liquid chromatography - MS Mass spectrometry - NSS nine salt solution     

Composition of the cell wall of Chlorella fusca

Isolated cell walls of mature Chlorella fusca consisted of about 80% carbohydrate, 7% protein, and 13% unidentified material. Mannose and glucose were present in a ratio of about 2.7:1 and accounted for most of the carbohydrate. Minor components were glucuronic acid, rhamnose, and traces of other sugars; galactose was absent. After treatment with 2 M trifluoroacetic acid or with 80% acetic acid/HNO₃ (10/1, v/v), a residue with a mannose/glucose ratio of 0.3:1 was obtained, probably representing a structural polysaccharide. An X-ray diffraction diagram of the walls showed one diffuse reflection at 0.44 nm and no reflections characteristic of cellulose. Walls from young cells contained about 51% carbohydrate, 12% protein, and 37% unidentified material. Mannose and glucose were also the main sugars; their absolute amounts per wall increased 6–7 fold during cell growth. Walls isolated with omission of a dodecylsulphate/mercaptoethanol/urea extraction step had a higher protein content and, with young walls, a significantly higher glucose and fucose content. These data and other published cell wall analyses show a wide variability in cell wall composition of the members of the genus Chlorella.Abbreviations GLC gas liquid chromatography - TFA trifluoroacetic acid     

Golgi Apparatus Mediated Polysaccharide Secretion by Outer Root Cap Cells of Zea mays. III. Control by Exogenous Sugars

Sugars supplied to germinating seedlings of maize (Zea mays L.) regulate the secretion of polysaccharides by the outer cells of the root cap. The polysaccharide secreted by these cells adheres to the root tip as a droplet and the size of the droplet was used to quantitate polysaccharide secretion. The polysaccharide contains glucose, galacrose, and galacturonic acid residues with smaller quantities of mannose, arabinose, xylose, fucose and rhamnose. These sugars supplied to maize seedlings had marked effects on the rate of polysaccharide secretion by root tips. The effects on secretion were independent of the growth rates of the roots. Glucose, fucose and xylose increased droplet size 1.5–2 fold (as did sucrose, maltose, lacrose, fructose and ribose) whereas galactose, arabinose and galacturonic acid were inhibitory. Mannose increased dropler size 5–7 fold. The marked effect of mannose on polysaccharide secretion was due to an increased rate of secretion combined with a longer phase of extrusion of polysaccharide into the forming droplet. The effect of mannose was partially reversed by inorganic phosphate and other sugars (except for fucose which had no effect or promoted secretion in the presence of mannose). In contrast to sucrose, mannose stimulated secretion in a maize variety having a high sugar endosperm (high endogenous sugar). The results suggest that regulation of secretion by mannose is due to an alteration of normal sugar metabolism; whereas stimulation of secretion by sucrose and other sugars may be due to an increased availability of sugars for metabolism.     

Production of Polysaccharide from Starch and Identification of Constituent Sugars of the Preparation

A bacterium which belongs to Achromobacter sp. was isolated and named as Achromobacter mucosum nov. sp. Starch and dextrin were essential carbon sources to produce a polysaccharide effectively by the bacterium. Maltotriose was as effective as starch for the production of the polysaccharide, and glucose, maltose, isomaltose and panose were little effective. This indicates that the bacterium requires a definite configuration of carbon source to produce the polysaccharide effectively. The dry powder of the polysaccharide was prepared from 10 liters of broth in the yield of 34.9 g. Glucose, galactose, mannose and uronic acid were confirmed as the constituent sugars of the polysaccharide and it was most probable that the uronic acid was d-glucuronic acid.     

An autolysin dissolves the inner cell wall layer of the algaPediastrum (Hydrodictyaceae)

Summary An autolysin produced by young colonies ofPediastrum frees them from the vesicle in which they are formed within 12 hours of release of zoospores from the parent cell. The polysaccharide vesicle is derived from the inner wall layer of the parent cell. Refrigeration delays vesicle disintegration; boiling stops it completely. A purified, lyophilized extract of the vesicle fluid added to boiled vesicled colonies removes the vesicle in 2 hours with the release of reducing sugars and polysaccharides.Biogel P2 and P10 chromatography of the products following incubation of the enzyme preparation and wall showed no more than 1% oligosaccharides; the remaining carbohydrates had a molecular weight of several thousand daltons. Analyses of isolated vesicle wall material (70–85% of the dry weight) showed mannose accounting for approximately 50% of the dry weight, with none of the other neutral sugars present (fucose, xylose, galactose and glucose) representing more than 3%. Uronic acids account for 20–25% of the wall weight, and proteins less than 2%. Pediastrum colonies are thus freed from the vesicles in which they are formed by the action of an autolysin they produce. The autolysin acts on the vesicle wall material to generate reducing sugars and cause it to disintegrate into its constituent polysaccharides.     

Cell wall metabolism in ripening fruit. VIII. Cell wall composition and synthetic capacity of two regions of the outer pericarp of mature green and red ripe cv. Jackpot tomatoes

Pericarp discs were excised from mature green and red ripe tomato (Lycopersicon esculentum Mill. cv. Jackpot) fruit and kept in sterile tissue culture plates for 4 days, including 2 days of incubation with D-[U-¹³C]-glucose. Cell walls were prepared and differentially extracted with dimethylsulfoxide (DMSO), trans-1,2-diaminocyclohexane-N,N,N′,N′-tetraacetic acid (CDTA). Na₂CO₃, 4 M KOH and 8 M KOH. Cell wall noncellulosic neutral sugar (NS) composition and cell wall synthetic capacity (i.e. incorporation of density label into cell wall sugars) were determined by using a gas chromatograph coupled to a flame ionization detector and a mass spectrometer, respectively. In the crude cell wall, there was significantly less galactose (Gal) and glucose (Glc) in the “outer”2-mm pericarp region, including the cuticle, compared to the “inner”2-mm region immediately below it (closer to the locules). In the CDTA-soluble pectin, rhamnose (Rha), arabinose (Ara) and Gal accounted for approximately 90% of the total NS. The ratios of these sugars were very similar in the total (¹²C plus ¹³C) sugars, and also in the newly synthesized ([¹³C]-labeled) sugars, suggesting that newly synthesized NS associated with the chelator-extractable pectic fraction has a composition very similar to that of preexisting NS. In the 4 M KOH-soluble material, xylose (Xyl) and Glc accounted for approximately 70% of the total NS. The ratio of these sugars was very similar in the total sugars, but much lower in the newly synthesized portion. This suggests that the hemicellulosic polymers synthesized during the ripening process are different in type and/or proportion from those present in the developing fruit. Because the outer pericarp of tomatoes contains at least two distinct tissue types and these have a distinct cell wall composition, analysis of tomato cell wall polysaccharide composition by homogenization of the entire outer pericarp will obscure subtle changes associated with ripening/softening within specific tissue types.     

Molecular Characteristics of Water-soluble Polysaccharide Extracted from Jelly Fig (Ficus awkeotsang Makino) Seeds

The molecular characteristics of polysaccharide obtained by extracting with water from jelly fig (Ficus awkeotsang Makino) seeds were elucidated by measuring the weight-average molecular weight (M_w) and radius of gyration (R_G), indicating the molecular expanse, by the light-scattering method.

The M_w and R_G values of the water-soluble jelly fig polysaccharide were 84–130 × 10⁴ and 240–450 mm, respectively, these values being larger than those of commercial LM pectin and HM pectin. In addition, the M_w and R_G values of the water-soluble jelly fig polysaccharide initially increased after being extracted, indicating the highest values 5 hours after the extraction, and thereafter decreased. These changes in the time-course of the molecule reflected well the changes with time in the mechanical characteristics and network structure of the water-soluble jelly fig polysaccharide gel. Exponent α in the expression was found to be 0.37. From these results, the conformation of the water-soluble jelly fig polysaccharide molecule after association by the contained inorganic elements proved to be of globular form rather than a random coil shape as a result of contraction of the molecule.     

COCCOLITH-ASSOCIATED POLYSACCHARIDES FROM CELLS OF EMILIANIA HUXLEYI (HAPTOPHYCEAE)1

Coccoliths of Emiliania huxleyi (Lohmann) Hay and Mohler, a unicellular calcifying alga, consist of calcite closely associated with an acidic, Ca²⁺-binding polysaccharide. This polysaccharide is thought to play a regulatory role in coccolith synthesis by interfering with CaCO₃ crystallization. Here we show that the polysaccharides from three different strains, A 92, L and 92 D, all inhibit the precipitation of CaCO₃ in vitro to the same extent. The monosaccharide compositions of the A 92 and L polysaccharide are similar. The 92 D material, however, deviates from the other two: it contains significantly lower amounts of methylated sugars and ribose, and elevated levels of rhamnose and galactose. It also contains antigenic determinants not detected in the A 92 and L polysaccharides. In contrast to the latter two macromolecules the 92 D polysaccharide migrates as two bands upon polyacrylamide gel electrophoresis, possibly resulting from complexing with small amounts of protein. The coccolith polysaccharide from L cells, cultured at an elevated growth rate, also migrates as two bands. This phenomenon is due to an increase in molecular size distribution. The results suggest that certain properties of the molecule may be subject to variation without interfering with its function.     

Structural studies of capsular polysaccharide of type XII Diplococcus pneumoniae

The capsular polysaccharide of Diplococcus pneumoniae Type XII contains residues of d-glucose and d-galactose in a molar ratio of 2:1. The methylated polysaccharide yielded upon hydrolysis 2,3,4,6-tetra- and 3,4,6-tri-O-methyl-d-glucose and 2,3,4,6-tetra-O-methyl-d-galactose as the only neutral methyl sugars. Periodate oxidation of the polysaccharide resulted in destruction of all neutral sugars and immunochemical activity against rabbit antisera. Periodate oxidation of the methyl O-methylglycosides obtained after hydrolysis of the methylated polysaccharide indicated that at least 30% of the l-fucosamine residues are substituted at C-4 in the polysaccharide. It is concluded that the polysaccharide consists of a hexosamine backbone that is substituted by d-galactosyl and kojibiosyl side-chains. The proposed terminal d-galactosyl residues apparently are sterically hindered from interacting with several d-galactose-binding proteins.     

Cell Wall Polysaccharide Biosynthesis by Membrane Fragments from Streptococcus pyogenes and Stabilized L-Form

The formation and composition of a cell wall rhamnose-containing polysaccharide by membrane fragments from Streptococcus pyogenes and its stabilized L-form were compared. Also, the effect of prior treatment on the ability of coccal whole-cell and membrane fragments to incorporate radioactivity from thymidine diphosphate-¹⁴C-rhamnose, and the results of subsequent attempts to remove labeled polysaccharide from such membranes are given. L-form membrane fragments were capable of only 10% uptake of ¹⁴C-rhamnose from this nucleotide as compared with streptococcal membranes. However, once bound, both membrane fragments polymerized rhamnose to the same extent. These findings tend to negate the almost complete lack of polymeric rhamnose within the intact L-form as being due to the absence of membrane enzymes necessary for the transfer of rhamnose from a suitable precursor to membrane acceptor sites or enzymes responsible for rhamnose polymerization. Degradation of labeled rhamnose polysaccharide after isolation from coccal membranes by mild acid hydrolysis showed muramic acid and glucosamine to be attached. This same polysaccharide from L-form membrane fragments was devoid of amino sugars. These data suggest the possible involvement of amino sugars in the attachment of cell wall polymeric rhamnose to the streptococcal cytoplasmic membrane. The absence of attached amino sugars to rhamnose polysaccharide from L-form membrane fragments is discussed in terms of this organism's continued inability for new cell wall formation. The isolation, from streptococcal membrane fragments, of a polysaccharide containing rhamnose and amino sugars common to at least two different streptococcal cell wall-type polymers was demonstrated.     

Formation of exopolysaccharides by Rhodococcus erythropolis and partial characterization of a heteropolysaccharide of high molecular weight

Summary Polysaccharide formation by Rhodococcus erythropolis was studied using lower mono-, di-and trihydric alcohols, sugars and n-alkanes as carbon sources. Cultural conditions of the organism were examined with regard to polysaccharide production. It was demonstrated that a glycerol substrate, an 30°C incubation temperature and a pH of 7.5 were optimal cultural conditions for polysaccharide formation. Addition of penicillin G in the decelerating growth phase increased the polysaccharide concentration in the culture filtrate to 3.1 g/l. One of the main extracellular heteropolysaccharides formed by Rhodococcus erythropolis consisted of glucose and mannose in the molar ratio 11, a small portion of protein and a trace of glucosamine. The molecular weight was to be 1·14×10⁶.