The Distribution of Polysaccharide Production in Aerobacter and Escherichia Strains and its relation to Antigenic Character:With a note on the Influence of Potassium Deficiency upon Production of Polysaccharide by Aerobacter aerogenes

Abstract

SUMMARY: Strains of Aerobacter aerogenes, A. cloacae and Escherichia coli, includingmucoid capsulate, mucoid non-capsulate, smooth and rough variant forms, were grown on defined agar media. The polysaccharide content of the cultures was estimated by the anthrone method and related to the amount of growth as measured by the non-dialysable nitrogen content. Polysaccharide production, as measured by the polysaccharide : nitrogen ratio, was increased in all strains when growth was limited by a restricted supply of nitrogen source so that added carbohydrate remained in relative excess. A low incubation temperature, 15-20° instead of 3 5 O , influenced polysaccharide production differently in the various strains and species ; thus it greatly increased production in E. coli strains, but decreased it in A. cloacae strains grown on certain media. The various strains showed considerable differences in the amount of polysaccharide production and in the distribution of the polysaccharide between the different possible sites of accumulation : i.e. intracellular, capsular and as loose slime. The mucoid strains produced the largest amounts of polysaccharide, most of which was present extracellularly as capsuIes or slime; the smooth strains produced much smaller amounts, almost entirely intracellular; a rough strain produced least of all. The antigenic constitution of certain strains was examined, particularly that of a mucoid capsulate A. aerogenes and mucoid non-capsulate and non-mucoid smooth variants derived from it. The designation of such morphological and immunological variants is discussed.The amount of polysaccharide produced varies greatly with different strains and species of Enterobacteriaceae. Among twelve strains of Escherichia coli grown at 13-17' on glucose medium, Morgan & Beckwith (1939) found that the amount of polysaccharide produced, as indicated by the degree of mucoidness, was large in five strains, moderate in two strains and small in the remainder ; they found similar differences among salmonella strains. Mucoid, smooth and rough variants of the same strain may also show great differences in polysaccharide production. (1951), using the periodate-Schiff staining method, found that 0-inagglutinable rough variants of salmonella and shigella strains lacked the stainable intracellular polysaccharide of the smooth parent strains ; they therefore suggested that this polysaccharide corresponded to the hapten of the 0 antigen characteristic of the smooth form.Duguid & Wilkinson (1953) studied the influence of different cultural conditions on the amount of polysaccharide produced by a single strain (A3) of Aerobacter aerogenes, distinguishing the polysaccharide situated intracellularly, in the capsules or in the loose extracellular slime. In the present investigation the same methods have been applied for examination of several different strains of A . aerogenes, A . cloacae and Eschrichia coli. For each strain the effect was observed of variation in the sugar:nitrogen ratio of the medium and of variation in th...

Escherichia coli O.128 Causing Gastro-enteritis of Infants

“…Therefore, in this paper, only the symbol C is used to avoid confusion with antigens which may be of a very different nature. Our results agree with those of Wilkinson, Duguid, and Edmunds (1954), who state that, "although differing morphologically, the slime antigens resemble the capsular antigens chemically and serologically." Henriksen (1949) has made a study of some mucoid strains, including E. co!i, showing capsules.…”

The synthesis of exopolysaccharide by Klebsiella aerogenes membrane preparations and the involvement of lipid intermediates

“…(iv) polymerization and extrusion into the extracellular environment. Associated with the final stage there must presumably be some mechanism of attachment to the cell surface, as it is known that stable mutants arise yielding exopolysaccharide slime but no discrete capsules (Wilkinson, Duguid & Edmunds, 1954 Scheme 1. Postulated structural arrangement for polysaccharide synthesis.…”

The composition of the extracellular polysaccharides of Aerobacter–Klebsiella strains

“…Strains Al and A3 correspond with type 54, strain A4 with type 8, and strain A29 with type 57. Although strains Al and A3 are identical antigenically, they differ in their characteristic capsule size, that of Al being much larger (Wilkinson et al 1954). Strains E26 (SI) and E29 (SI) are non-capsulate slime-forming mutants isolated by Dr P. N. Edmunds from types 26 and 29 of Edwards & Fife. Aero.…”

“…cloacae strains NCTC 5920 and NCTC 5936 were obtained from the National Collection of Type Cultures, Colindale, London; under most conditions they are non-capsulate organisms, producing small amounts of slime. The distribution of polysaccharide production in some of these strains has been studied by Duguid & Wilkinson (1953) and Wilkinson et al (1954).…”

“…The view has been held that slime and capsule are of different origin, that slime is a secretion, whereas capsules arise through cell-wall swelling (Etinger-Tulczynska, 1933), but it is now generally believed that both slime and capsule are secretion products (see Dubos, 1945;Knaysi, 1951;Lamanna & Mallette, 1953). It has been shown with pneumococcus type III (Wood & Smith, 1949) and Aerobacter-Klebsiella strains (Edwards & Fife, 1952;Wilkinson, Duguid & Edmunds, 1954) that the slime and capsule of capsulate strains are identical antigenically. However, the chemical identity of slime and capsular polysaccharide has yet to be shown.…”