Amino acids, amino sugars and sugars present in the cell wall of some strains of Streptococcus pyogenes

Biology of the group E streptococci: a review

Group E streptococci are identified by a group antigen consisting of a cell wall rhamnose-glucose polymer. Other specific cell wall polysaccharides separate the group into at least six serotypes (II, IV, V, VI, VII and VIII). No species name has been accepted for the group E Streptococcus, although the organism is often designated as Streptococcus infrequens or S. lentus. Recently, the name S. porcinus has been proposed for a species that would include streptococci of groups E, P, U and V. Group E streptococci are fairly widely distributed in animals, especially swine, and are occasionally isolated from bovine milk. They cause streptococcal lymphadenitis of swine, an economically important disease, particularly in the United States. They do not appear to be the primary cause of any other disease or condition. The organisms enter the swine host through the mucosa of the pharyngeal or tonsillar surfaces, and are carried to the lymph nodes, primarily of the head and neck region, where abscesses are formed. Cell wall antigens induce the formation of serum agglutinins; a microtitration agglutination test, based upon reactions involving the type IV antigen, is considered a reliable test for detection of infection in animals. Antigenic components include group and type antigens, extra-cellular enzymes, and an antiphagocytic factor which may be associated with virulence of the organism and with protective immunity to streptococcal lymphadenitis of swine. This factor, a surface protein, develops on cells cultured in media fortified with serum, rendering the cells resistant to phagocytosis by porcine leukocytes. The classification, morphology, physiology, biochemistry and nutrition of the group E streptococci, and methods for their isolation, cultivation, and identification are reviewed.

Peptidoglycan types of bacterial cell walls and their taxonomic implications

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The serum opacity reaction of Streptococcus pyogenes: general properties of the streptococcal factor and of the reaction in aged serum

The capacity of certain strains ofStreptococcus pyogenesto produce opacity in aged horse serum has been studied. Cells from all stages of the growth cycle are able to produce opacity. Maximal activity is reached towards the end of the exponential phase of growth.

Examination of cell fractions obtained by mechanical breakage and differential centrifugation suggested that the cell-bound activity is predominantly associated with the membrane fraction. Extraction with sodium deoxycholate yields a soluble fraction of high activity.

There is considerable strain variation in heat stability of the serum opacity factor. Cell-bound activity is often quite resistant to heat, whereas extracted activity is less stable.

Low concentrations of divalent cations have an activating effect, whereas high concentrations inhibit the serum opacity reaction. High concentrations of uni-valent cations are without effect on the cell-free enzyme but have an activating effect on the cell-bound enzyme.

For both the cell-bound and the cell-free enzyme the pH optimum was 5·8.

Although sensitive to trypsin and pepsin, the serum opacity factor appears to be resistant to streptococcal proteinase. Its activity is destroyed by formaldehyde and by periodate but is unaffected by a number of reducing agents.

Pre-heating of the serum or the addition of iodoacetate did not affect the serum opacity reaction. The enhanced cholesterol esterification previously described with fresh serum appears to be a secondary reaction. Even when isolated by relatively gentle methods, α-lipoprotein serves as a substrate only in the presence of crystalline serum albumin.

Cell wall composition in relation to the taxonomy of some Actinoplanaceae

Hydrolytic residues of the cell walls of 48 strains of Actinoplanaceae, previously assigned to 10 species and the four genera, Actinoplanes, Ampullariella, Amorphosporangium, and Pilimelia, were examined by paper chromatography and column chromatography. Comparisons were made for taxonomic purposes between the groupings obtained, by use of chemical characters and the groupings currently recognized morphologically. Most of the species investigated had qualitatively distinct cell wall compositions. Often, however, the cell wall compositions of species in different genera were more similar, in some respects, than were those of species in the same genus. Quantification of the cell wall amino acids and amino sugars substantiated that cross-generic similarities existed. Based on these results and the morphological conclusions reached by other investigators, a single-genus concept is suggested for the Actinoplanaceae examined.

Studies on the immunochemistry of streptococcal mucopeptide

Streptococcal mucopeptide, solubilized by either ultrasonic treatment or lysozyme, gave a precipitin reaction with rabbit antimucopeptide serum. A haptenic inhibitor of this reaction, which was composed of alanine, glutamic acid, and lysine in a mole ratio of 4:1:1, was isolated from a Streptomyces albus enzymes digest of Group D cell walls by ion exchange chromatography. When selected antisera were employed, greater than 90% inhibition of the mucopeptide quantitative precipitin reaction was achieved with 2 mg/ml of this inhibitor, whereas a hexosamine fraction with minimal concentrations of amino acid residues was inactive in this respect. These results suggest that the peptide moiety is an antigenic determinant of mucopeptide. Preliminary results indicate that the hexosamine polymer of the mucopeptide is a secondary antigenic determinant.