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PubMed1983

Special bacterial polysaccharides and polysaccharases.

Alcaligenes faecalis var. myxogenes 10C3, which we isolated from soil, produces a water-soluble and an insoluble extracellular polysaccharide. The former (succinoglycan) is composed of glucose, galactose, pyruvic acid and succinic acid (molar proportions 7:1:1:1) with (beta 1-3)-, (beta 1-4)- and (beta 1-6)-glucosidic linkages. The latter (curdlan) is composed entirely of (beta 1-3)-linked D-glucose and forms a resilient firm gel when heated in suspension. The organism also produces extracellularly a repeating-unit octasaccharide of succinoglycan and cyclic (beta 1-2)-D-glucan. These polymers or oligomers are also produced by many strains of Agrobacterium and Rhizobium. Spontaneous mutation in ability to produce these polysaccharides or oligosaccharides occurs in these strains. The structures of succinoglycan, and similar polymers containing riburonic acid or galactose as the end residue of the side chain, were elucidated by successive fragmentation with two special enzymes obtained from Cytophaga arvensicola followed by methylation analysis. It is interesting that the unit compound in the biosynthesis of succinoglycan is identical with the unit compound in the enzymic decomposition of the polymer. Studies on curdlan gel by X-ray, 13C n.m.r. and electron-microscopic analysis and other physicochemical methods showed that the molecular structure of curdlan changes from a single helix to a triple stranded helix on heat treatment at high temperature. Curdlan seems to be useful for making new types of jelly products and may also be useful in new procedures for food production. Interestingly, curdlan possesses marked antitumour activity. Extracellular isoamylase (EC 3.2.1.68; glycogen 6-glucanohydrolase) of Pseudomonas amyloderamosa SB 15, which we isolated from soil, is very useful for elucidation of the structure of amylopectin and glycogen, and also for the commercial production of amylose or maltose alone or in combination with beta-amylase. Maltose is useful as a sugar for injection, being better than glucose. Maltitol is easily produced from maltose by chemical reduction and is used as a low-calorie sweetener. The isoamylase is also effective for enhancing the production of glucose from starch by the action of glucoamylase.

Alcaligenes↗
PubMedDate not supplied

[Specific blast transformation of rabbit spleen cells induced by a bacterial polysaccharide and inhibitory effect of peripheral blood lymphocytes (author's transl)].

Following immunization with bacteria (i.e. Salmonella johannesburg), rabbit spleen lymphocytes developed a specific blast response when the lymphocytes were stimulated with polysaccharide, the haptenic moiety of lipopolysaccharide. A clear cut dissociation was noted in the blast response induced by polysaccharide compared with those induced by lipopolysaccharide and lipid A. There was no correlation between the magnitude of the cellular responses and that of the antibody response. Moreover, there was less specificity at the cellular level than at the level of antibody secreted by cells. A decrease of 3H-thymidine incorporation was often observed after immunization, at the level of peripheral blood lymphocytes. An inhibitory effect of these cells was shown on the blast response of spleen lymphocytes with polysaccharide. A high blast response to Salmonella polysaccharide which could be observed in some non-immunized rabbits might be related to a natural sensitization of animals with the same or related unknown antigens which could not be recognized by anti-S. johannesburg antibodies.

Animals↗
PubMedDate not supplied

[Antigenic bacterial polysaccharides. Structure of O-specific polysaccharides from Pseudomonas cepacia serogroups C, I, O1, and O4].

Like some Pseudomonas cepacia serogroups studied earlier, serogroups C, I (Nakamura), O1 and O4 (Heidt) are characterized by the presence of at least two structurally different O-antigenic polysaccharide chains in cell-wall lipopolysaccharides. On the basis of acid hydrolysis, methylation, 1H- and 13C-NMR spectroscopy, including computer-assisted 13C-NMR-based analysis, the complete structures of the predominant polysaccharides of serogroups I (I), C and O4 (III) and the minor polysaccharides of serogroups I (II) and O1 (V) were established, and the structure of the predominant polysaccharide of serogroup O1 (IV) established earlier (Cox A. D., Wilkinson S. G.@Carbohydr. Res. 1990. V. 195. No 2. P. 295-301) was confirmed.

Burkholderia cepacia↗
PubMedDate not supplied

[The effect of bacterial polysaccharides on the course of a Mycoplasma infection].

Polysaccharides of Clavibacter michiganense have been studied for their effect on Mycoplasma infection. It is established that content of T-lymphocytes truthfully increased in the groups of animals whose PS 1 and PS 2 were administered both with protective and medical purpose as compared with that in a group of animals with natural course of mycoplasmosis. Under these conditions the effect of polysaccharides on T-helpers were not evidently expressed, while they exerted considerable effect on T-suppressors, normalizing their high index in the animals infected by Mycoplasma hominis. Polysaccharides also exerted a normalizing effect on the content of T-killers, whose level in the animals with natural proceeding of mycoplasmosis was considerably decreased. One can observe a decrease of content of B-lymphocytes (which approached the level of their control in a group of conditionally healthy animals) under the effect of polysaccharides as compared to infected animals. Metabolic processes are activated in immunocompetent cells as affected by polysaccharide. Results obtained when studying the effect of polysaccharides on immunologic factors in the animals with mycoplasma infection as well as histomorphological data confirm the above evidences that polysaccharides of C. michiganense are promising immunomodulators.

Adjuvants, Immunologic↗