Advances in Applied Microbiology

constant and variable sequences which may occur either at the level of DNA or RNA. It is now generally accepted, that both B and T lymphocytes directly participate in antigen recognition, but the existence and nature of T cell receptors is still debated. Some could not find them; others could, but found them passively absorbed. When they were detected, they looked IgM-like (IgT) or like IgA with nonassociated heavy and light chains. One wonders whether these contradictory findings could be assigned to difficulties with techniques, or whether the elusiveness of T cell receptors is at the heart of the problem, and perhaps eventually most of the disagreements will be reconciled without questioning the validity of observations. The nature of signals, the role of different lymphocyte populations and macrophages in accepting, handling and responding to these signals were major concerns of immunology in 1974. Impressive amounts of data have been presented from different groups suggesting that suppressive and synergistic T cells play a central role in immunological responsiveness. There are important new contributions to the molecular mechanism of lymphocyte activation, such as the role of cyclic nucleotides , which may play a direct or potentiating role in the mechanism of clonal expansion and antibody formation. The volume may be valuable both as source and reference book for immu-nologists and interested outsiders as well. The omission from the text of the discussions might have been justified by the speed of publication at the time when the conference was held; but already a year later, it appears to be a regrettable loss. This volume includes a wide spectrum of topics, such as microbial antime-tabolites, microbial taxonomy (its relationship to cell lipids, numerical techniques in yeast classification), fungal sterols, microbiology of soy sauce fermentation and of brewing, biodegradation of linear alkylbenzene sulfonate, and penicillin acylases. Further articles deal with education and training in applied microbiology, with the history of the American Type Culture Collection, and with selected aspects of applied microbiology. The volume's purpose-to present the "state of the art" in various fields-is admirably served by the individual articles, written by renowned authors in the fields, and supplemented with extensive bibliographies. Only the paper on "Contemporary Thoughts on Aspects of Applied Microbiology" seems diffuse; those who expect too much from its all-encompassing headings will be disappointed. I was particularly intrigued by Wayne W. Umbreit's thoughts on "Education and Training in Applied Microbiology." Too few …