The Characteristics of Extracellular Protein Secretion by Staphylococcus aureus (Wood 46) and their Relationship to the Regulation of  -Toxin Formation

Abstract

SUMMARYThe progress of secretion of a-toxin and total extracellular protein by Staphylococcus aureus (Wood 46), grown aerobically at 37 "C, in a 3% (w/v) tryptone soya broth medium supplemented with vitamins was followed. Exoprotein was secreted at a high rate by intact bacteria during the exponential phase (to 9 h) and into the post-exponential phase. After 18 h, when exoprotein accounted for 33% of the total protein in the culture, no further exoprotein was secreted although the bacterial density continued to increase at a low rate beyond this time. During the phase of active secretion, a-toxin represented a constant proportion of total exoprotein, the differential rate of synthesis of which increased by a factor of four after the end of exponential growth. Concomitant with the increase in the differential rate of exoprotein formation there was a fourfold increase in the intracellular concentration of RNA precursor material.

Genetic regulation of fatty acid modifying enzyme from Staphylococcus aureus

“…toxin was expressed in the Sar' and Agr' strains but was not detected in the Sarand Agr-strains as has been reported previously (data not shown) [8,16,181.…”

“…Other investigators have demonstrated the importance of global regulators in controlling the expression of several staphylococcal extracellular proteins [8][9][10][11][12][13][14][15][16][17][18][19][20]. Two of these regulatory elements, the accessory gene regulator (Agr) and the staphylococcal accessory regulator (Sar), control expression of exoproteins by transcriptional control [ 13,141.…”

Effect of four antibiotics on haemolysin production and adherence to human uroepithelial cells by Escherichia coli

“…The precise function of membrane-bound ribosomes remains unknown, although they may represent the site of synthesis of certain macromolecules, including exotoxins. Abbas- Ali and Coleman (1977) have shown that exoprotein synthesis in S. aureus, which occurs primarily in the early part of the logarithmic phase of growth, may account for only 33% of the total bacterial protein formed. This suggests that much of the biosynthetic potential of the cell is consumed by this process and, therefore, may be open to inhibition by antibiotics as seen in the present experiments.…”

Cloning and physical mapping of the Staphylococcus aureus rplL, rpoB and rpoC genes, encoding ribosomal protein L7/L12 and RNA polymerase subunits and '

“…The molecular characterization of S. aureus Rif' Expmutants may give insights into the structure and function of RNA polymerase and the interaction of RNA polymerase with regulatory signals involved in postexponential phase expression of exoprotein virulence factors (Abbas-Ali & Coleman, 1977;Janzon et al, 1986;Iandolo, 1989;Kornblum et al, 1990;Vandenesch et al, 1991). As an essential step in this analysis, the rpoBC region of S. aureus has been cloned and mapped.…”