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At least 19 recordsLinked to original sources
PubMed1977

Idiotypes on galactan binding myeloma proteins and anti-galactan antibodies in mice.

Antibodies with specificity for beta1,6 linked D-galactoses were induced in mice by immunization with gum ghatti. Idiotypic antisera were prepared in rabbits and mice by immunization with 8 BALB/c IgA(k), beta1,6D-galactan binding myeloma proteins (beta6GALBMP). Two kinds of idiotypic sera were obtained: cross-specific sera that reacted with two or more beta6GALBMP but not other BALB/c myeloma proteins, and individual idiotypic sera that reacted with only the beta6GALBMP used in the immunization. Antibodies with specificity for beta1,6 linked D-galactans shared cross-specific idiotypes with beta6GALBMP. Only one of seven individual idiotypes associated with beta6GALBMP was found on galactan antibodies. Since all beta6GALBMP thus far have the same Vk and VH isotope composition the results indicate an extensive heterogeneity among galactan-binding immunoglobulins in BALB/c mice. It is speculated that some of this diversity may arise from somatic rather than germ line gene mutations.

Animals↗
PubMed1991

Expression of two structurally distinct D-galactan O antigens in the lipopolysaccharide of Klebsiella pneumoniae serotype O1.

The lipopolysaccharide (LPS) molecule is an important virulence determinant in Klebsiella pneumoniae. Studies on the serotype O1 LPS were initiated to determine the basis for antigenic heterogeneity previously observed in the O1 side chain polysaccharides and to resolve apparent ambiguities in the reported polysaccharide structure. Detailed chemical analysis, involving methylation and 1H- and 13C-nuclear magnetic resonance studies, demonstrated that the O-side chain polysaccharides of serotype O1 LPS contained a mixture of two structurally distinct D-galactan polymers. The repeating unit structures of these two polymers were identified as [----3)-beta-D-Galf-(1----3)-alpha-D-Galp-(1----] (D-galactan I) and [----3)-alpha-D-Galp-(1----3)-beta-D-Galp-(1----] (D-Galactan II). D-Galactan I polysaccharides were heterogeneous in size and were detected throughout the sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis (PAGE) profile of O1 LPS. In contrast, D-galactan II was confined to the higher-molecular-weight region. The structures of the two D-galactans were not influenced by simultaneous synthesis of a capsular K antigen. Apparently, neither of the D-galactans constitutes a common antigen widespread in Klebsiella spp. as determined by immunochemical analysis. Examination of the LPSs in mutants indicated that expression of D-galactan I can occur independently of D-galactan II. Transconjugants of Escherichia coli K-12 strains carrying the his region of K. pneumoniae were constructed by chromosome mobilization with RP4::mini-Mu. In these transconjugants, the O antigen encoded by the his-linked rfb locus was determined to be D-galactan I, suggesting that genes involved in the expression of D-galactan II are not closely linked to the rfb cluster.

Antigens, Bacterial↗
PubMed1992

Molecular cloning of the rfb region of Klebsiella pneumoniae serotype O1:K20: the rfb gene cluster is responsible for synthesis of the D-galactan I O polysaccharide.

Previous chemical analyses identified two structurally distinct O polysaccharides in the lipopolysaccharide of Klebsiella pneumoniae serotype O1:K20 (C. Whitfield, J. C. Richards, M. B. Perry, B. R. Clarke, and L. L. MacLean, J. Bacteriol. 173:1420-1431, 1991). The polysaccharides were designated D-galactan I and D-galactan II; both are homopolymers of galactose. To begin investigation of the synthesis and expression of these O polysaccharides, we have cloned a 7.3-kb region of the chromosome of K. pneumoniae O1:K20, containing the his-linked rfbkpO1 (O-antigen biosynthesis) gene cluster. In Escherichia coli K-12 and Salmonella typhimurium, rfbkpO1 directed the synthesis of D-galactan I but not D-galactan II. The cloned rfbkpO1 genes did not complement a mutation affecting D-galactan II synthesis in K. pneumoniae CWK37, suggesting that another (unlinked) locus is also required for D-galactan II expression. However, plasmids carrying rfbkpO1 did complement a mutation in K. pneumoniae CWK43 which eliminated expression of both D-galactan I and D-galactan II, indicating that at least one function is common to synthesis of both polymers. Synthesis of D-galactan I was dependent on chromosomal galE and rfe genes. Hybridization experiments indicated that the rfbkpO1 sequences from different serotype O1 Klebsiella isolates showed some restriction fragment length polymorphism.

Cloning, Molecular↗
PubMed1986

Contribution of the VK4 light chain to antibody specificity for lysozyme and beta (1,6)D-galactan.

The VL amino acid sequence of an anti-lysozyme hybridoma protein, HyHEL-5, was determined. HyHEL-5 expresses a V region of the VK4 family and JK1. The VK4 family also includes light chains from galactan binding antibodies, although sequence comparisons suggest that a different member of this family is used to encode HyHEL-5. The HyHEL-5 light chain has a deletion of residue 96, such that L3 is one residue shorter than the majority of murine L3. Chain recombination experiments, employing H and L chains from different anti-galactan and anti-lysozyme binding antibodies, were performed to examine the contribution of the H and L chain in dictating specificity for either galactan or the lysozyme epitope recognized by HyHEL-5. The results indicate that, although the ability to bind galactan vs lysozyme is absolutely heavy-chain dependent, having the appropriate heavy chain is not sufficient for specific high affinity binding. Both the L chains from HyHEL-5 and J539 (a galactan-binding myeloma protein) were capable of supporting binding to galactan in combination with the J539 H chain, but affinity for galactan is less with the HyHEL-5 L chain. Only VK4 L chains supported binding of the HyHEL-5 heavy chain to the HyHEL-5 epitope, although binding with the J539 L chain was low affinity and relatively nonspecific.

Amino Acid Sequence↗
PubMed1976

Acute respiratory, circulatory and pathological changes in the calf after intravenous injections of the galactan from Mycoplasma mycoides subsp. mycoides.

Twenty of 28 calves, 10-12 weeks of age when given intravenous injections of the galactan from Mycoplasma mycoides subsp. mycoides, showed transient apnoea, increased pulmonary arterial and decreased systemic arterial blood pressures, and increased packed-cell volume. Necropsy revealed haemorrhages associated with alveolar ducts and vessel walls, areas of pulmonary oedema, usually associated with the haemorrhages, dilated airways and, in some, capillary thrombosis. Animals that had shown changes in blood pressure and respiration in response to a dose of galactan did not react to a second dose an hour later. One goat tested died, four lambs were mildly affected and a cat and several rats and guinea-pigs did not respond. It is suggested that the galactan released biogenic amines that produced the effects listed. Immunological mechanisms were discounted on the grounds that only a small amount of antigenic material was injected at the time the reaction occurred, and neither serological nor skin tests produced any evidence of prior sensitisation to the galactan or a similar substance. A relationship between reactivity to the galactan and susceptibility to the natural disease has been suggested. This, together with the pulmonary oedema found in galactan-treated calves and in natural lesions of contagious bovine pleuropneumonia (CBPP), and the possibility that contraction of blood vessels could be an initiating cause of thrombosis indicates the role that galactan may play in the pathogenesis of CBPP.

Animals↗
PubMed1991

The galactan-degrading enzymes in the snail Biomphalaria glabrata.

1. Embryonic snails incorporate from the perivitelline fluid in which they are embedded a polysaccharide, called galactan, which is composed entirely of D-, or D- and L-galactose. In this investigation the p-nitrophenyl-beta-D-galactoside degrading enzyme of Biomphalaria glabrata which was assumed to be involved in the degradation of the galactans was purified almost to homogeneity and its specificity was studied. 2. It has a mol. wt of 135,000 and is composed of two identical subunits. 3. It could be shown that p-nitrophenyl-beta-D-fucoside was hydrolysed eight times faster, but native galactan was neither decomposed nor was it inhibitory for the hydrolysis of p-nitrophenyl-glycosides. 4. Thus, it is most likely that this galactosidase is not involved in the galactan metabolism. 5. However, a membrane-bound enzyme complex was revealed which was able to metabolize the native galactan of Biomphalaria glabrata completely and which showed graded reactivity towards galactans of other species. 6. Since no intermediate degradation products were found it must be assumed that they were metabolized further in the mitochondria.

Animals↗
PubMed1977

Structure of the D-galactan isolated from garlic (Allium sativum) bulbs.

Hot-water extraction of defatted garlic-bulbs yielded a mixture of polysaccharides containing a D-galactan, a D-galacturonan, an L-arabinan, a D-glucan, and a D-fructan. A trace of L-rhamnose was also detected in the polysaccharide hydrolyzate. The pectic acid was partially removed by precipitation with aqueous calcium chloride; from the remaining polysaccharide mixture, a pure D-galactan containing 97.3% of D-galactose was isolated by fractional precipitation and repeated chromatography through a column of DEAE-cellulose. Methanolysis and hydrolysis of the permethylated D-galactan yielded 2,3,4,6-tetra-, 2,3,6-tri-, and 2,3,di-O-methyl-D-galactose in the molar proportions of 1:2:1. On periodate oxidation, the D-galactan reduced 1.18 molar equivalents of the oxidant per D-galactosyl residue, and liberated one molar equivalent of formic acid per 4.13 D-galactosyl residues. Smith degradation of the D-galactan was also conducted. From these results, a structure has been assigned to the repeating unit of the D-galactan.

Galactose↗
PubMed1987

The reactivity of galactose oxidase with snail galactans, galactosides and D-galactose-composed oligosaccharides.

The enzymic oxidation of snail galactans, of their first and second Smith degradation products and of some structurally related polysaccharides was studied. Lymnaea stagnalis galactan after one cycle of Smith degradation reacted best and native Helix pomatia galactan was almost inactive. Investigations on the structural requirements for oligosaccharides to bind to galactose oxidase showed that the branched tetrasaccharide, Gal-beta-1----6-[Gal-beta-1----3]-Gal-beta-1----1 L-Gro, in the terminal nonreducing position was the most complementary structure in the native galactan to associate with the enzyme. All nitrophenyl alpha-galactosides reacted better, and the ortho-form was 10-times more potent compared with this tetrasaccharide, indicative of the involvement of a hydrophobic region in binding. However, the beta-linked isomers were only equally or less reactive than galactose. The enzymic oxidation determined colorimetrically by transferring the peroxide formed to o-dianisidine ceased at a maximum typical for each substrate and independent of the reaction time. When the absolute turn-over rates for ortho- and para-nitrophenyl alpha-galactoside and for the beta-isomer were determined by HPLC, it could be demonstrated that the oxidation had not finished at the maximum of the colour reaction, but proceeded until the substrate was consumed. The initial speed of the colour reaction paralleled the absolute oxidation rate.

Animals↗
PubMed1986

The role of phosphate groups in the interaction of human C-reactive protein with galactan polysaccharides.

Human C-reactive protein (CRP) shows binding specificities for phosphate monoesters, polycations and for several other biological macromolecules lacking these ligands. We report here that the formerly observed interaction of CRP with snail galactans, as exemplified by Helix pomatia galactan, is not due to a lectin-like carbohydrate-binding reactivity, but, instead that CRP obviously binds to phosphate groups that are minor constituents of these polysaccharides. Structural analysis of the galactan revealed that the phosphate groups are attached by a, as yet unidentified, linkage group to the carbohydrate backbone. Thus, the anti-galactan reactivity of CRP can be attributed to the protein's classical anti-phosphate/anti-phosphorylcholine specificity.

Animals↗
PubMed1986

The galactan-binding immunoglobulin Fab J539: an X-ray diffraction study at 2.6-A resolution.

The crystal structure of the Fab of the galactan-binding immunoglobulin J539 (a mouse IgA,kappa) has been determined at a resolution of approximately 2.6 A by X-ray diffraction. The starting model was that obtained from the real space search described previously (Navia, M.A., Segal, D.M., Padlan, E.A., Davies, D.R., Rao, D.N., Rudikoff, S. and Potter, M. "Crystal structure of galactan-binding mouse immunoglobulin J539 Fab at 4.5 A resolution." Proc. Nat. Acad. Sci. USA, 76:4071-4074, 1979). This Fab structure has now been refined by restrained least-squares procedures to an R-value of 19% for the 11,690 unique reflections between 8.0 A and 2.6 A. The rms deviation from ideal bond lengths is 0.025 A. The overall structure differs from McPC603 Fab, another mouse IgA,kappa antibody, in that the elbow bend, relating the variable and constant parts of the molecule, is 145 degrees vs. 133 degrees for McPC603. The region of the molecule expected to be the antigen binding site contains a large cavity with two clefts leading away from it. This has been fitted with a model of an oligo-galactan.

Animals↗
PubMed1990

Structural studies on the galactan from the snail Helix pomatia.

1. The galactan of the snail Helix pomatia was subjected to two cycles of Smith-degradation and the resulting products were isolated by gel filtration and thin layer chromatography. 2. The structures of the low molecular weight oligosaccharides were elucidated being identical to those obtained from Lymnaea stagnalis galactan. However, the quantities released differed significantly between the two species. The high molecular fractions comprising about 66% of the material were not obtained in a similar degradation of the Lymnaea stagnalis galactan. 4. Thus the observed structural differences can explain easily the species-specific reactivity among the two polysaccharides seen earlier with lectins, enzymes and antibodies.

Animals↗
PubMed1986

Immuno- and histochemical studies on galactan and human blood group-related receptors in the bovine lung.

Using a monoclonal anti-galactan antibody and streptococcus B type II antibody, the distribution of lung galactan could be demonstrated for the first time in a vertebrate organ. In addition to the immunochemical demonstration of the bovine lung galactan, a human blood group A-like glycoprotein is detectable by lectinological methods in the bovine lung tissue. Various other lectin-receptors, for instance those of the peanut lectin (PNA) or for lectins with L-fucose (UEA) and N-acetyl-lactosamine (ECA) specificity show a typical staining pattern in bovine lung.

Amino Sugars↗
PubMed1985

Group B streptococcus type II antisera have anti-galactan specificities.

It has been confirmed by immunochemical methods that group B streptococcal capsular polysaccharides of type II contain terminal non-reducing beta-(1-6)-D-galactosyl groups. This immunodominant structure is detected by immune antisera from rabbits. As beta-(1-6)-D-galactosyl residues are the predominant end groups of a number of plant and animal galactans, anti-type II streptococcus antisera can also be used as anti-galactans. On the other side, different anti-galactans from various origins (lectins, myeloma proteins) can be applied to identify group B streptococcal type II strains. In addition, it is shown that other group B streptococcal types can also be recognized by different lectins.

Agglutination Tests↗
PubMed1992

Structural diversity among sulfated alpha-L-galactans from ascidians (tunicates). Studies on the species Ciona intestinalis and Herdmania monus.

Sulfated polysaccharides occurring in the tunic of different species of ascidians differ markedly in electrophoretic pattern and chemical composition. A purified sulfated alpha-L-galactan from Herdmania monus was studied using methylation analysis and NMR spectroscopy; it is composed mainly of 3-sulfated 4-linked alpha-L-galactopyranoyl units. This is the first description of a homo-polymer of sulfated alpha-L-galactose. In contrast, the sulfated L-galactan from Ciona intestinalis shows marked structural heterogeneity and a low sulfate content. These data indicate unusual structural diversity among sulfated L-galactans from different species of ascidians.

Animals↗
PubMed1978

Evaluation of oral iron galactan as a method of iron supplementation for intensively housed sucking piglets.

Iron supplementation of piglets with oral galactan given as a single dose within 24 hours of birth was evaluated in a series of on farm trials. The growth rate of piglets receiving this treatment was faster than that of piglets receiving single injections of iron dextran or iron galactan at 3 days of age, or ferrous sulphate crystals orally at weekly intervals. Mean values for red cell parameters of oral iron galactan supplemented piglets at 2 to 4 weeks of age were lower than those of injected piglets but there was no clinical evidence of anaemia in any of the piglets.

Administration, Oral↗
PubMed1978

Structure of a beta-galactan isolated from the nuclei of Physarum polycephalum.

A sulfated and phosphorylated beta-D-galactan ([alpha]D+8degrees) was isolated from the nuclei of the acellular slime mould Physarum polycephalum. The polysaccharide was isolated from cesium chloride gradients during the preparation of ribosomal DNA and purified. The purified galactan contained 89% galactose, 2.5% phosphate and 9.6% sulfate groups and had an average degree of polymerisation of 560. Periodate degradation and permethylation studies indicated the presence of mainly (1 leads to 4)-, but also of (1 leads to 3)-, and (1 leads to 6)-linked galactose units with one branch every 13 units. These results suggested that the intranuclear galactan, apart from its higher sulfate content, is similar to the extracellular polysaccharide produced by P. polycephalum.

Chemical Phenomena↗