Cross-linking of cell wall proteins by oxidative
burst induced by hypoosmotic or mechanical stress in tobacco cells. A,
SDS-PAGE and silver staining of cell wall proteins extracted from
untreated cells (lane a), 5 min after cell transfer in isoosmotic
medium (lane b), hypoosmotic medium (lane c), hypoosmotic medium
containing 20 μm IDP (lane d), after 20 min of mechanical
stress in culture medium (lane e) or culture medium containing 20
μm IDP (lane f), after 5 min of in vivo treatment of
cells by 1 mm H2O2 (lane g) or 5
min of in vitro treatment of proteins by 2 mm
H2O2 (lane h). B, Western blot of cell wall
proteins corresponding to cells transferred in hypoosmotic medium
containing 20 μm IDP (a) or hypoosmotic medium without
IDP (b). St, Molecular mass standards (in kilodaltons). Arrowheads in A
and B indicate the 115-kD bands.