THE FOCUS OF THESE PROPOSED EXPERIMENTS IS ON THE CONTRIBUTION OF THE AGR QUORUM-SENSING/CELL COMMUNICATION SYSTEM TO S. AUREUS GROWTH AND VIRULENCE POTENTIAL UNDER SIMULATED MICROGRAVITY CONDITIONS WHICH WILL ENABLE US TO BETTER DESIGN FOLLOW UP SPACE FLIGHT EXPERIMENTS. THEREFORE THIS PROPOSED RESEARCH ALSO RELATES TO RESEARCH EMPHASIS 4 (MOLECULAR AND CELLULAR BIOLOGY ELEMENT) BY ASSESSING THE "IMPACT OF SPACEFLIGHT ON CELL TO CELL INTERACTIONS AND COMMUNICATION". UP TO 30% OF THE HUMAN POPULATION ARE COLONIZED WITH S. AUREUS. IT IS CONSIDERED PART OF THE NORMAL HUMAN MICROBIOTA AND EXTREMELY DIFFICULT TO COMPLETELY REMOVE FROM THE BODY. THESE EXPERIMENTS WILL CONTRIBUTE TO A BETTER UNDERSTANDING OF THE EFFECTS OF SPACE FLIGHT ENVIRONMENTAL CONDITIONS ON S. AUREUS-HUMAN INTERACTIONS WHICH WILL ALLOW US TO DESIGN EFFECTIVE COUNTERMEASURES THAT WILL PROTECT ASTRONAUT HEALTH DURING LONG-TERM SPACE FLIGHT MISSIONS.