Figure 4

Network-based identification of novel genes for virulence-associated phenotypes. (A) The blood agar plate streaked with wild-type Staphylococcus aureus exhibited beta-type hemolysis, whereas the plate streaked with the mutant S. aureus with the SAUSA300_RS06165 gene exhibited gamma-type hemolysis. (B) Hemolysis activity (OD₄₅₀) of the wild-type S. aureus and the mutant S. aureus with the SAUSA300_RS06165 gene. Error bars represent the standard error, and the double asterisk signifies a P-value ≤ 0.01 (two-tailed t-test). (C) Hemolysis gene network including a novel hemolysis gene, RS06165 (red node) and its within-group connectivity score (red dot). Significance of the observed network connectivity was measured by using a null distribution based on 10000 random gene sets. (D) Biofilm-forming capability was normalized to the bacterial growth (OD₅₅₀/OD₆₀₀) of the wild-type and mutant S. aureus. Error bars represent the standard error, the single asterisk represents a P-value ≤ 0.05, and the double asterisks represent P-values ≤ 0.01 (two-tailed t-test). (E) Biofilm gene network including five novel biofilm genes (red nodes) identified in this study and its within-group connectivity score (red dot). Significance of the observed connectivity was tested as for (C).