This compendium is the result of the FEMS Workshop on "Rapid Diagnosis of Mycoplasmas" which I organized and which took place in Jerusalem, Israel, August 11-23, 1991. The first week's sessions were held at a resort on the outskirts of Jerusalem and consisted of lectures and discussions. This part was modelled along the lines of the Gordon Conference in the USA, i.e., in an intimate atmo sphere in which everyone could mix and exchange ideas, and was very benefi cial. About 100 scientists from around the world attended the first week. Dur ing the first week, the biology, molecular biology and pathophysiology of myco plasmas, as well as all the main diagnostic methods were covered, including both conventional and the newer technologies. The session on mycoplasmas in the human urogenital tracts was held in conjunction with the Israel Society for the Study and Prevention of Sexually Transmitted Disease. The second week was a laboratory session and was held at the Hebrew University-Hadassah Medical School campus in Ein Karem, Jerusalem. All ex periments were conducted by eminent specialists in their field. The lab session had 36 participants from 19 countries who used the most modern techniques for the diagnosis of mycoplasmas in medicine, veterinary medicine and agri culture. The efficacy of several commercial kits were also tested at this time. I want to again thank everyone who helped and supported this work shop, as well as the authors of the various chapters.

The mycoplasmas, a trivial name used to denote organisms included in the class Mollicutes, are a group of prokaryotic organisms comprising more than 120 species distinguished from ordinary bacteria by their small size and the total lack of cell walls. The absence of a cell wall in mycoplasmas is a characteristic of outstanding importance to which the mycoplasmas owe many of their pecu liarities, for example, their morphological instability, osmotic sensitivity, unique ion pumping systems, resistance to antibiotics that interfere with cell wall bio synthesis, and susceptibility to lysis by detergents and alcohols. The fact that the mycoplasma cells contain only one membrane type, the plasma membrane, constitutes one of their most useful properties for membrane studies; once the membrane is isolated, it is uncontaminated with other mem brane types. Another advantage in using mycoplasmas as models for membrane studies stems from the fact that their membrane lipid composition can be altered in a controlled manner. This characteristic results from the partial or total inabili ty of the mycoplasmas to synthesize long-chain fatty acids and cholesterol, making mycoplasmas dependent on the supply of fatty acids from the growth medium. The ability to introduce controlled alterations in the fatty acid composi tion and cholesterol content of mycoplasma membranes has been utilized in studying the molecular organization and physical properties of biological mem branes.

The emergence of pathogens resistant to conventional antimicrobial agents has forced us to intensify the efforts in search for new approaches to prevent infectious diseases. Such a direction was indicated in studies over the last two decades showing that adhesion of pathogens, primarily via glycoconjugate or protein receptors of the host tissue, is crucial for the infectious process. Moreover, it was found that infection can be prevented by blocking adhesion of the pathogen to mucosal surfaces of the host. The various aspects of interference with the process of microbial adhesion as a way of preventing diseases were the subject of the Bat-Sheva Seminar, "Towards Anti-Adhesion Therapy of Microbial Infectious Diseases," held in Zichron Yaakov, Israel, February 25 to March I, 1996. A major aim of the Bat-Sheva de Rothschild Foundation for the Advancement of Science in Israel, which sponsors a series of seminars, ours among them, is to provide the necessary tools and settings for international forums and exposure of young scientists and promising students to the state of the art of the field. This goal has been achieved during the week's discussions, and its major aspects are presented in this compendium. The seminar's participants, as well as the readers of this book, thank the founder and Foundation for their support. This book includes the major themes of this rapidly growing area. However, by no means do we intend to cover every bit and piece in it. The book's first section deals with the lectin-sugar interactions and their inhibitors.