 interaction between the quality of the environment and the health of the exposed population determines the survival response of living organisms . 
 the phenomenon of induced tolerance by exposure to threshold levels of stressors to stimulate natural defense mechanisms has potential therapeutic value . 
 the paucity of information on predictability of individual response and information on the operative fundamental mechanisms limit applicability of the adaptive tolerance strategy . 
 a potential biomarker of the stress response includes members of the stress - inducible ubiquitin gene family . 
 transcript sizes detected with northern blot analysis identify different classes of ubiquitin gene family members and the intensity of the radioactive signal allows abundance determinations . using moderate exercise as the stressor , significant increase ( p < 0.028 ) in abundance of inducible polyubiquitin genes was found in human blood . both the potential of exercise as a model system of a natural stress inducer and polyubiquitin as a biomarker of stress were established in these studies.imagesfigure 1figure 2 
Images