Immunoelectron Microscopic Study of the Location of Group-specific and Type-specific Polysaccharide Antigens on Isolated Walls of Group B Streptococci

Wagner, Manfred; Wagner, Barbara; Kubín, V.

doi:10.1099/00221287-120-2-369

Cited by 13 publications

(7 citation statements)

References 7 publications

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“…Ultrastructural studies have demonstrated that some GBS strains show a remarkable variation in the size of the enveloping polysaccharide capsule (16). This finding agrees with the present results showing that an apparently homogeneous strain may contain subpopulations of bacteria with different buoyant densities.…”

Section: Discussionsupporting

confidence: 93%

Density profile of group B streptococci, type III, and its possible relation to enhanced virulence

Håkansson¹,

Holm²,

Wagner³

1987

J Clin Microbiol

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The buoyant densities of virulent and colonizing group B streptococci, type III, were determined by centrifugation of bacteria on a linear, hypotonic density gradient. A total of 28 strains were investigated. Eleven strains were obtained from blood cultures of babies with early-onset disease, and eight strains were isolated from the cerebrospinal fluid of babies with late-onset septicemia and meningitis. Nine colonizing strains were genital isolates from pregnant women subsequently giving birth to healthy children. In each strain the buoyant density was determined before and after neuraminidase treatment. All strains showed an increase in the buoyant density after enzymatic removal of sialic acid, and the density differences before and after desialylation were calculated. The mean values of these differences for blood, cerebrospinal fluid, and colonizing isolates were 23.4, 25.3, and 10.6 mg/ml, respectively. The mean value for the colonizing strains differed significantly from the mean value for each group of virulent strains. All colonizing strains banded singly in the gradient, whereas five of the virulent strains divided into two density populations. Extracts of the low-density cells produced markedly more dense immunoprecipitates with type antiserum than did extracts of the high-density bacteria. One double-banding strain was positive for R protein. After separation of the two density populations, this antigen was detected only in the low-density population. The results indicate that bacterial buoyant density is inversely related to the amount of capsular polysaccharide enveloping the cell and that a determination of the density profile of the bacteria may be used for discriminating strains with an increased pathogenic potential.

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Section: Discussionsupporting

confidence: 93%

Density profile of group B streptococci, type III, and its possible relation to enhanced virulence

Håkansson¹,

Holm²,

Wagner³

1987

J Clin Microbiol

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“…On the other hand, labelling with conjugated specific antibodies shows that the envelope incorporates and transports antigens belonging to the extemal layers of the ce11 wall. This observation has also been made on Gram-positive (Swanson et al 1969;Chem Lai et al 1973;Wagner et al 1980) and Gram-negative bacteria (Bayer and Thurow 1977).…”

Section: Resultssupporting

confidence: 50%

Demonstration of an external layer in several species of the genus Brucella

J¹,

Caravano²,

Roux³

1982

Can. J. Microbiol.

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OBERTI, J., R. CARAVANO, and J. Roux. 1982. Demonstration of anextemal layer in several species of the genus Brucella. Can. J. Microbiol. 28: 1300-1303. An extemal layer suggesting a capsule was demonstrated by electron microscopy on three strains of Brucella belonging to different species. This structure was disclosed only after the action of antibodies and was not present on al1 the bacteria exarnined; labelling with conjugated specific antibodies showed that it incorporates and transports antigens belonging probably to the outer membrane. Staining by ruthenium red showed that it contains acidic mucopolysaccharides.OBERTI, J., R. CARAVANO et J. Roux. 1982. Demonstration of an external layer in several species of the genus Brucella. Can.J. Microbiol. 28: 1300-1303. Une enveloppe externe, évoquant une capsule, a été mise en évidence, par microscopie électronique, chez trois souches de Brucella d'espèces différentes. Cette structure n'était apparente qu'après action des anticorps, et n'était présente que chez une partie des bactéries; un marquage avec des anticorps spécifiques couplés a montré qu'elle incorpore et transporte des antigtnes appartenant probablement à la membrane externe. La coloration par le rouge de ruthénium a révélé qu'elle contient des mucopol ysaccharides acides. IntroductionThe existence of an extemal layer (glycocalyx, slime layer, or microcapsule) in Brucella has been variously reported. Its presence has been postulated in early publications (Huddleson 1940; Mickle 1940); some current treatises of bacteriology consider that the S phase is normally encapsulated (Davis et al. 1970), while others restrict this structure to the M phase, considering that it results, rather, from the growth conditions (Smith et al. 1964). However, recent monographs describe Brucella species as having no capsule (Alton et al. 1977). The seventh edition of Bergey's manual of determinative bacteriology (Breed et al. 1957) describes Brucella species as "encapsulated," whereas the eighth edition reports "no capsule" (Brinlay-Morgan and McCullough 1974). In view of the biological importance of the capsule, we have therefore undertaken to demonstrate it clearly for three strains of Brucella belonging to different species.

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“…The ultrastructure of streptococci such as S. pneumoniae (36, 37), S. mutans (29), and group B streptococci (20,26,33,39) has been examined. Surface fibrils or fimbriae were observed on different strains of S. salivarius (13), S. sanguis (14), S. mitior (12), and Enterococcus faecalis (15).…”

mentioning

confidence: 99%

Ultrastructural study of surface components of Streptococcus suis

et al. 1990

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The presence of capsular material on cells of nine reference strains of Streptococcus suis representing serotypes 1 to 8 and 1/2 was determined by transmission electron microscopy after polycationic ferritin labeling, immunostabilization, or fixation with a combination of glutaraldehyde and lysine. All the cells of the reference strains examined were covered with a layer of capsular material whose thickness varied between 20 to 30 nm and 350 to 375 nm when examined by immunostabilization. Capsular material from cells exposed to homologous antiserum was usually thicker than that from polycationic ferritin-labeled cells or cells fixed with glutaraldehyde-lysine. Negative staining revealed detectable surface structures on S. suis strains. All strains carried peritichous, thin, and flexible fimbriae with a diameter of approximately 2 nm and a length of up to 250 nm. This study indicated that morphological differences of surface structure exist among S. suis reference strains.

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Immunoelectron Microscopic Study of the Location of Group-specific and Type-specific Polysaccharide Antigens on Isolated Walls of Group B Streptococci

Cited by 13 publications

References 7 publications

Density profile of group B streptococci, type III, and its possible relation to enhanced virulence

Density profile of group B streptococci, type III, and its possible relation to enhanced virulence

Demonstration of an external layer in several species of the genus Brucella

Ultrastructural study of surface components of Streptococcus suis

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