Effect of Bactericidal Substance from Staphylococcus aureus on Group A Streptococci II. Structural Alterations.

Ultrastructural alterations brought about by treatment of a beta-hemolytic streptococcus with a bactericidal substance from Staphylococcus aureus are described and illustrated. The substance causes an early condensation of nucleoid deoxyribonucleic acid (DNA) and a partial loss of ribosomes. These changes are followed by a dissolution of the cell contents resulting in bacterial "ghosts" composed of empty cell wall and capsule. These morphological findings correlate with known biochemical effects of the bactericidal substance on ribonucleic acid degradation and cessation of DNA and protein synthesis.