Biomembranes – serie

Both science and religion are aspects of human endeavor that do not observe political constraints. It is therefore appropriate that contributions should come from many different countries for a series which attempts to chronicle developments in an interdisciplinary field such as membrane research. This volume is an excellent example of the diversity of thinking, background, and approach needed by the working scientist for his re­ search planning. From Canada comes a review by Silverman and Turner of the mech­ anisms by means of which the plasma membrane of the renal proximal tubule acts as a transport mediator. The two chapters that were writtyn by American scientists are excellent examples of the comparative bio­ chemical approach. Inouye feels he must apologize for being interested in the outer membrane of E. coli, but it is obvious, after a reading of his chapter, that no apology is required. On the contrary, we are grateful for his drawing our attention to this system and its unique properties. Holtz­ man, Gronowicz, Mercurio, and Masur are also on a consciousness­ raising mission in summarizing for us a number of integrated functions of membranes using the toad bladder as an experimental system. The other two chapters of this volume come from overseas. N orthcote has again demonstrated his capacity to integrate a complex and difficult field.

Molecular transport of substances in the presence or absence of membranes is an ubiquitous phenomenon. Research workers from various disciplines in the biological and phys- ical sciences are actively pursuing problems of transport. One of the important questions arising in numerous biological transport situations concerns the differentiation between passive and active transport. The latter is a more complex phenomenon involving metabolic processes, and the economy of thinking requires that attempts to explain any transport pro- cess from passive mechanisms should be carried as far as pos- sible before invoking more complex mechanisms. A precise de- finition and circumscription of passive transport processes is of crucial importance. The symposium on "Passive permea- bility of cell membranes" was therefore devoted to these pas- sive transport processes and this book presents the proceed- ings of the conference. This symposium, a satellite symposium of the XXV Inter- national Congress of Physiological Sciences at Munich, Ger- many, on July 25-31, 1971, was organized by the Department of Physiology, University of Nijmegen, Nijmegen, The Nether- lands.It was held at the Hilton Hotel in Rotterdam on July 20-22, 1971. The meeting was made possible by generous fi- nancial support from the Dutch Ministry of Education and Science (Ministerie van Onderwijs en Wetenschappenl and from Boehringer Mannheim N. V. , Ciba N. V. , Essex (Nederland) N. V. , Gist-Brocades N. V. , Hoffmann - La Roche N. V. , Merck, Sharp and Dohme Nederland N. V. , N. V. Philips, and Unilever N.

This volume contains the contributions to a symposium held at Gatlinburg, Tennessee, under the auspices of the Oak Ridge National Laboratory, in April, 1971. In the past, these proceedings had appeared as a supplement to the Journal of Cellular Physiology. Due to the nature of the subject ma­ terial and the relevance of the topic of the symposium to the readers of BIOMEMBRANES, it was agreed by the organizers of the symposium to publish the contributions of the partici­ pants as a separate volume in BIOMEMBRANES. It had been originally envisaged that, from time to time, the proceedings of a conference whose subject matter was directly related to the scope of this series would be included. The proceedings are being published exactly as they have been submitted to the Editor without the usual editorial re­ V1S10n. This is being done to increase the speed of publica­ tion. For the same rOeason, no indices have been provided since the time needed to prepare an adequate subject index would have unnecessarily delayed publication. Included in the proceedings are short reports of a number of workshops that were held during the conference. The editor has received excellent cooperation from both the organizers of the conference and the several contributors to this volume. If the experiment is a success, it is thanks to their promptness.

Not many years ago, problems of membranes and transport attracted the attention of but a few dozen enthusiasts, mainly physiolo­ gists who recognize~ the significance of membranes for the stabilization of the general steady state of organisms. The first symposium organ­ ized some fifteen years ago could boast of the attendance of perhaps fifty scientists (the remaining fifty were not yet sure that membranes was the topic of their choice), ranging in specialization from physical chemistry to bacterial genetics, who clairvoyantly decided to study what now has become the number one subject at most congresses of biophysics, physiology, and even biochemistry and microbiology. As is the case with many rapidly developing fields, the interest in membranes and transport seems to be growing out of bounds and the whole field of membra no logy, interdisciplinary as it is, has penetrated into the realms of a number of branches of physics, chemistry, and biology. Its subject is primarily biological and, although much has been done in the world to increase the "exactness" of biology over the past thirty years, one cannot strive for a rigorous mathematical description of biological phenomena since, as M. H.

It might be asked if there is a need for yet another large review on Intestinal Absorption, and the answer is that this is still a rapidly expanding field of interest both from the medical and scientific points of view. There is ample evidence for this in the number of papers which continue to be published, and the bul­ letin on Intestinal Absorption issued by the Biomedical Infor­ mation Project of the University of Sheffield lists about 150 titles per month, and there is still no sign of any diminution in this rate. There are in fact so many papers that those interested in intestinal absorption have to be specialists in one particular field, but must at the same time be aware of the general deve­ lopments in the subject as a whole. The last major review was the excellent volume in the American Handbook published in 1968, already six years ago, and indeed a number of the con­ tributors to that volume have taken part in the present work. Some observations made in the introduction to a volume of the British Medical Bulletin on Intestinal Absorption some years ago are still pertinent. Progress in the experimental sciences is not continuous, but proceeds in phases of rapid expansion alter­ nating with periods of slower growth.

The aim of this book is to bring together in one volume the current research and thought on the concept of membrane fluidity as a biological phenomenon. The invited articles are intended to review recent develop­ ments in the areas of membrane research covered and to summarize the current concepts and theories in those areas. The authors have been given ample opportunity to present their thoughts and speculation on membrane fluidity and related phenomena in a more expanded form than is usually possible in reviews of this type. It is hoped that this approach will have a stimulating effect on research and theoretical development in the biomem­ brane field. The chapters in this book are arranged in three sections, the first of which covers physical studies of membrane fluidity and related phenomena on the molecular level. Included are chapters on intermolecular hydrogen bonding between membrane lipids, thermal analysis of membranes, appli­ cation of fluorescence and NMR spectrometry to the study of membrane fluidity, and the effect of drugs and other compounds on membrane stability and fluidity. The second section deals with the regulation of membrane fluidity in microorganisms, plants, and higher organisms by factors such as tem­ perature, fatty acid chain length, lipid desaturation, and polar head group structure.

It was a warm, sunny morning in Rehovot. The sky was c1ear as it always is in June. As I walked to the Institute that morning, too many cars were passing by, too many people were hurrying onto the Institute's grounds. No one was smiling, acquaintances were recognized by a slight nod of the head. When I turned the corner, a few people already had gathered on the lawn in front of the Jacob Ziskind building. This number was to swell to thousands before the service was over. We were to be joined by the President of Israel, its first Prime Minister, many members of the cabinet, and other great, near-great, working colleagues, and residents of the town. The purpose of all this activity was written on everyone's face, and underlined by the casket that lay in the rotunda of the building. His wife was sitting there, his children, his brother, his students both past and present. One could hear the silence of the participants. I stood inside for a while, overlooking the rotunda. A long line of mourners filed by, offering their sympathies to the family. Suddenly a woman, dressed in black, fell to her knees in front 9f Rina, sobbing. It was the wife of the Japanese Ambassador to Israel. I moved to join the crowd outside. People were standing on the lawn, gingerly trying to avoid stepping on a flower.

The most valuable service Dr. Gel'man and her colleagues have performed for the many investigators of bacterial membrane systems in producing their first excellent monograph on "The Respiratory Apparatus of Bacteria" in 1966 has been continued and expanded in the preparation of this volume. The au­ thors have brought together in a single volume much of the detail of investiga­ tions of bacterial membranes at the ultrastructura11eve1 and the chemical and biochemical organizationa11eve1s. The approach in bringing together this rap­ idly increasing volume of discovery has been both comprehensive and system­ atic, with a constant awareness of the importance of the molecular and func­ tional properties and relationships existing in various bacterial membranes. The monograph naturally reflects the authors' interest and their own inti­ mate involvement in the elucidation at the molecular level of the respiratory chains organized in the prokaryotic bacterial membrane system. It is entirely appropriate that the chapter devoted to this topic should occupy a substantial proportion of this monograph. Indeed, had this volume been prepared at this very moment, that proportion would have been even greater, as the work in .