Summary: Recent research has implicated nitric oxide (NO) in the induction of the hypersensitive response (HR) during plant–pathogen interactions. Here we demonstrate that Arabidopsis suspension cultures generate elevated levels of NO in response to challenge by avirulent bacteria, and, using NO donors, show that these elevated levels of NO are sufficient to induce cell death in Arabidopsis cells independently of reactive oxygen species (ROS). We also provide evidence that NO‐induced cell death is a form of programmed cell death (PCD), requiring gene expression, and has a number of characteristics of PCD of mammalian cells: NO induced chromatin condensation and caspase‐like activity in Arabidopsis cells, while the caspase‐1 inhibitor, Ac‐YVAD‐CMK, blocked NO‐induced cell death. A well‐established second messenger mediating NO responses in mammalian cells is cGMP, produced by the enzyme guanylate cyclase. A specific inhibitor of guanylate cyclase blocked NO‐induced cell death in Arabidopsis cells, and this inhibition was reversed by the cell‐permeable cGMP analogue, 8Br‐cGMP, although 8Br‐cGMP alone did not induce cell death or potentiate NO‐induced cell death. This suggests that cGMP synthesis is required but not sufficient for NO‐induced cell death in Arabidopsis. In‐gel protein kinase assays showed that NO activates a potential mitogen‐activated protein kinase (MAPK), although a specific inhibitor of mammalian MAPK activation, PD98059, which blocked H₂O₂‐induced cell death, did not inhibit the effects of NO.

Exercise-induced muscle damage (EIMD) is accompanied by localized oxidative stress / inflammation which, in the short-term at least, is associated with impaired muscular performance. Dietary antioxidants have been shown to reduce excessive oxidative stress; however, their effectiveness in facilitating recovery following EIMD is not clear. Blueberries demonstrate antioxidant and anti-inflammatory properties. In this study we examine the effect of New Zealand blueberries on EIMD after strenuous eccentric exercise.