600
Inactivation of the heat shock gene dnaK or vraSR which encodes a two - component regulatory system that responds to peptidoglycan biosynthesis inhibition led to an increase in TTO susceptibility which demonstrates a protective role for these genes in the S . aureus TTO response .
 None
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: Chemical 
Text: {0} 
Answer:
 None