We investigate structural and cytochemical areas of membrane biology. We use a series of methods developed in our laboratory, in particular: a) fracture-flip (to obtain images of the outer and cytoplasmic surfaces of plasma membranes and maps of the distribution of surface receptors and antigens by immunogold labelling; b) label-fracture and replica staining label-fracture (to relate the inner structure of the membrane to its surface topochemistry); and c) simulcast (to compare nanoanatomical views of membrane surfaces with freeze-fracture aspects and cytochemical maps in one single membrane). We investigate the localization of cytoplasmic and of membrane-associated oncogene products; the ultrastructural pathology of human parasites; the membrane dynamics of CD4 and of HLA antigens; cellular basis of bacterial infections; and ultrastructural and cytochemical aspects of the maturation of mouse mammary tumor virus and of nerve cells in culture. In addition, we continue our research on the structure of the zonula occludens, to determine transcellular continuity of the exoplasmic leaflets of the plasma membrane. Project numbers Z01 08374-06 and Z01 08376 are now combined with this project.
