V

Preface

Studies of the bacterial cell wall emerged as a new field of research in the early 1950s and, literally, took off primarily thanks to the pioneering work of Milton R.J. Salton. Since then, it has flourished in a multitude of directions and has reached the stage where the preparation of a monograph as a ‘one-man show’ is no longer possible. This volume is the result of a joint venture involving numerous contributors. Following a historic pers- pective of the field (Chapter l), it has been conceived as an attempt to single out topics of great conceptual importance related to those groups of macromolecules which are loca- lized outside the permeability barrier, i.e. the cytoplasmic membrane, of the Eubacteria, with special emphasis on the genetic, molecular and, when possible, atomic levels.

Peptidoglycan, the basic matrix of the bacterial wall, is present in all vegetative cells, except the L-forms and Mycoplasma, and is an essential constituent of bacterial endo- spores (Chapters 2-8). Teichoic and teichuronic acids, lipoteichoic acids, lipoglycans, neutral complex polysaccharides and several specialized proteins are frequently unique wall-associated components of Gram-positive bacteria (Chapters 9-1 1). Lipopoly- saccharides, lipoproteins and a multitude of proteins including porins, form the outer membrane of the Gram-negative bacteria (Chapters 12-20). The periplasm is a trans- shipment region localized between the plasma membrane and the outer membrane (Chapter 21).

Bacterial cells know how to adapt to changing environmental conditions and, for that purpose, they have evolved signal transduction pathways. These pathways generally are initiated by ‘receptors’ consisting of a sensory domain which is responsible for signal reception on the outer face of the plasma membrane and a cytosolic domain which is re- sponsible for the generation of an intracellular signal. Examples of adaptative responses of this kind are discussed in Chapters 22-24.

Acquired resistance to known antibiotics by an increasing number of bacterial species has become such an utterly serious concern that, in terms of effective antibacterial chemotherapy, the 1990s are beginning to look like the ‘pre-antibiotic era’. This situation is the grim harvest of ignorance and complacency. It demands urgent attention. Chapters 25-27 deal with the underlying mechanisms of bacterial resistance to the main chemo- therapeutically useful ‘cell wall’ antibiotics, the 8-lactams and the glycopeptides.

With the rapid growth of scientific literature in the field, it was impossible to condense all the accumulated knowledge in a book of the size of the present volume. There are gaps. In particular, no chapter is devoted to the walls of Mycobacterium tuberculosis and M . leprue which are plagues that massively affect much of the Third World. Inevitably also, the book will contain ‘out of date’ sections by the time it is published. In spite of these imperfections, we hope that it provides an integrated collection of contributions forming a fundamental reference for researchers and of general use to teachers and ad- vanced students in the life sciences. We also hope that it can provide useful guidelines

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for those wishing to make an informed decision about whether research on the bacterial cell wall is worth funding in these times.

Research often begins with a question. This book witnesses the multifaceted pursuits of scientists engaged in bacterial cell wall research with many of the why’s, how’s and wherefore’s that they strive, with increasing success, to answer. We thank them for their valuable contributions. We a lso express our gratitude to Professor Laurens L.M. van Deenen, general co-editor of the New Comprehensive Biochemistry series who initiated this venture, to Mrs Amanda Shipperbottom and Mrs Annette Leeuwendal, publishing editors, and Mr. Dirk de Heer, desk editor, of Elsevier Science B.V., who produced the book.

Regine Hakenbeck Berlin

Jean-Marie Ghuysen Libge

October 1993.