Figure 1.
Schematic of Mga regulon patterns.
Mga (multigene activator) is a positive regulator of a number of streptococcal genes. The most prominent of these are the family of M proteins whose genes are tandemly linked. sof and sfbx are bicistronic and are also regulated by Mga, but are located some distance away. emm encodes for M protein, mrp encodes M-related proteins, enn encodes an M-like protein that binds IgA, and scpa encodes a C5a peptidase. Some serotypes contain only mga, emm, and scpa (pattern A). Other serotypes contain one or more of the remaining genes (patterns B–E). The M1, M5, M6 and M24 strains in this work are pattern A; the M18 strain is pattern C; and the M2, M4, and M49 strains are pattern E. Figure derived from data and classification scheme of Bessen at al. [14], [15], [16].
Table 1.
Biofilms, hydrophobicity, and surface, membrane-bound, and culture released LTA of Streptococcus pyogenes
Figure 2.
Effect of growth medium on biofilm formation.
A. The growth of M type 4 S. pyogenes in the indicated media was determined by measuring the A530 after a 48 hour incubation at 37°C. B. The formation of biofilms by M type 4 S. pyogenes grown for 48 hours at 37°C in the indicated media. These experiments were done in quadruplicate and the mean±SD is shown.
Figure 3.
Biofilm formation and hydrophobicity of S. pyogenes.
A. Biofilm formation by the various serotypes was determined by the microtiter assay as described in Materials&Methods. Black bars indicate biofilm formation by various serotypes and white bars indicate formation of biofilms in the presence of trypsin. B. Hydrophobicity of S. pyogenes. Black bars indicate the degree of hydrophobicity of the various serotypes as measured by their ability to bind to hexadecane. White bars indicate the percent hydrophobicity after trypsin treatment. All experiments were done in triplicate and performed at least twice. The mean±SD is shown.
Figure 4.
Effect of inactivation of emm in pattern A serotypes on biofilm formation, hydrophobicity, and LTA expression.
The values for the wild type parental strain was used as the control and set at 100% in each case and data for the mutants are provided as percent of control (data from table 1). The horizontal line at the 100% mark represents the values for parental controls, which are not individually shown.
Figure 5.
Effect of inactivation of emm, mrp, enn or spa in patterns C, D, and E serotypes on biofilm formation, hydrophobicity, and LTA expression.
The values for wild type parental strain was used as the control and set at 100% and the data for mutants are provided as percent of control (data from table 1). The horizontal line at the 100% mark represents the values for parental controls, which are not individually shown.
Figure 6.
Correlation of membrane-bound LTA with trypsin extracted LTA and with LTA released into the culture media.
The amount of LTA bound to membranes was compared to the amount of LTA released into the culture media (A) and to the amount of LTA extracted with trypsin (B). There was a significant degree of correlation in each case, r = 0.730.
Figure 7.
Effect of variable expression of Emm1 on hydrophobicity, biofilm formation, and protein-bound LTA.
A. Microtiter wells were coated with the indicated streptococci and then reacted with rabbit anti-SM1(1-26) serum followed by peroxidase-conjugated, goat anti-rabbit Ig. B. The hydrophobicity of the streptococci was determined by adhesion to hexadecane as described in Materials and Methods. C. The ability of the streptococci to form biofilms was determined by the microtiter assays as described in Materials and Methods. D. The amount of protein-bound LTA (trypsin extractable) for the streptococci was determined as described in Materials and Methods. All assays were done in triplicate and the S.D. is shown.