For the past year, our researchers have established a network of collaborative studies that link our expertise in immunogold labeling cytochemistry and in a unique system of methods developed in our laboratory over the past decade (fracture-label, label-fracture, fracture- flip, and simulcast). To this end, postdoctoral fellows bring their backgrounds and research interests and actively seek projects where answers depend on cytochemical and ultrastructural analysis. Seven main projects are described: (A) immunogold cytochemical localization of oncogenes and oncogene-related proteins (Rulong); (B) immunocytochemical study of the retroviral infection (Risco); (C) effects of the interaction of bacterial endotoxins on the plasma membrane of macrophages and pneumocytes (Risco); (D) nanoanatomy and topochemistry of the cell surfaces of protozoan parasites (Pimenta); (E) ultrastructural aspects of 67 kD laminin receptor and its precursor processing in metastatic potent cells (Romanov); (F) freeze-fracture immunocytochemical study of the expression of native and recombinant GABAA receptors (Caruncho); and (G) ultrastructure and response to darkness of goldfish meninges (Caruncho). The emphasis of our research reflects an attempt where a diverse group of scientists, all with a strong background in cellular ultrastructure and topochemistry, provides unique, critical skills and approaches to scientists in areas as diverse as oncogene biology, molecular neurobiology, virology, bacteriology, parasitology, as well as the biology of metastatic cells. Within our Section these scientists, while pursuing well-focused projects, interact mutually and develop the basis for future independent research careers.