LIFE SCIENCES BY SIMON SILVER Department of Microbiology & Immunology University of Illinois Chicago, Ill. The protein secretory apparatus E. coli is being taken apart and put together in vitro like a Tinkertoy: SecA is a peripheral membrant ATPase of 102 kdaltons. SecB is separate and exists as a cytoplasmic tetramer of 16x4=64 kdaltons that is sufficient by itself for transport of some exported polypeptides. M. Watanabe, G. Blobel, “Cytosolic factor purified from Escherichia coli is

BY SIMON SILVER Department of Microbiology & Immunology University of Illinois Chicago, Ill " Berkeley virologist Peter Duesberg has carried out a campaign questioning whether the HIV retrovirus is the etiological agent of AIDS. A previous expression of Duesberg’s views appeared in Science (241, 5 14-17, 29 July 1988); a recent article presents the latest version of his arguments against H1V as the agent of AIDS. P.H. Duesberg, “Human immunodeficiency virus and acquired immunodefic