We are studying methanotrophic bacteria (MOB) in the rhizosphere of rice and other wetland plants and have good evidence from process studies that MOB are living in the interior of rice roots. In an experiment with gnothobiotic plants (sterile plants inoculated with a pure culture of MOB) we would like to check for the presence of MOB in the root cells or in the aerenchyma by using a CLSM. We could allready detect the bacteria on the root surface by using a specific antibody. To check for the intracellular occurence of the MOB we need a protocol to make the cell walls permeable for the antibody; can anybody help? Peter ---------------------------------------------------------- Peter Frenzel Max-Planck-Institut fuer Terrestrische Mikrobiologie Abt. Biogeochemie Karl-von-Frisch-Str. D-35043 Marburg Germany Tel +49-6421-287062 FAX +49-6421-161470