The origin of energy-conserving organelles, the mitochondria of all aerobic eukaryotes and the plastids of plants and algae, is commonly thought to be the result of endosymbiosis, where a primitive eukaryote engulfed a respiring -proteobacterium or a phototrophic cyanobacterium, respectively. While present-day heterotrophic protists can serve as a model for the host in plastid endosymbiosis, the situation is more difficult with regard to (the preceding) mitochondrial origin: Two chapters describe these processes and theories and inherent controversies. However, the emphasis is placed on the evolution of phototrophic eukaryotes: Here, intermediate stages can be studied and the enormous diversity of algal species can be explained by multiple secondary and tertiary (eukaryote-eukaryote) endosymbioses superimposed to the single primary endosymbiotic event. Steps crucial for the establishment of a stable, mutualistic relationship between host and endosymbiont, as metabolic symbiosis, recruitment of suitable metabolite transporters, massive gene transfer to the nucleus, development of specific translocases for the re-import of endosymbiont proteins, etc. are discussed in individual chapters. Experts, dealing with biochemical, genetic and bioinformatic approaches provide insight into the state of the art of one of the central themes of biology. The book is written for graduate students, postdocs and scientists working in evolutionary biology, phycology, and phylogenetics.

This volume is based on a FEMS Symposium entitled "Bacterial Growth and Lysis: Metabolism and Structure of the Bacterial Sacculus" held at the Monastery of Lluc (Mallorca, Spain) on 5-10 April, 1992. The goals of the symposium were to assess the present state of knowledge on the structure and physiology of the bacterial murein sacculus, and to develop new hypotheses and strategies to promote further development of the field. Consequently, the contributions compiled in this volume include broadly different approaches, from the introduction of new analytical methods to the presentation of provocative models for cell wall growth and division. Structural, biochemical, and genetic aspects are widely covered with special emphasis on the enzymology and regulation of murein hydrolases (autolysins). Comprehensive reviews on bacterial S layers and yeast cell walls are included to stimulate conceptual cross-feeding with these closely related topics. We believe that this book will provide the reader with a useful and up-to-date review of the topic. We would feel deeply rewarded by any positive influence this book may have on the future progress of the field, whereby all the scientific credit for it should be given to the authors of the excellent contributions presented."

The origin of energy-conserving organelles, the mitochondria of all aerobic eukaryotes and the plastids of plants and algae, is commonly thought to be the result of endosymbiosis, where a primitive eukaryote engulfed a respiring -proteobacterium or a phototrophic cyanobacterium, respectively. While present-day heterotrophic protists can serve as a model for the host in plastid endosymbiosis, the situation is more difficult with regard to (the preceding) mitochondrial origin: Two chapters describe these processes and theories and inherent controversies. However, the emphasis is placed on the evolution of phototrophic eukaryotes: Here, intermediate stages can be studied and the enormous diversity of algal species can be explained by multiple secondary and tertiary (eukaryote-eukaryote) endosymbioses superimposed to the single primary endosymbiotic event. Steps crucial for the establishment of a stable, mutualistic relationship between host and endosymbiont, as metabolic symbiosis, recruitment of suitable metabolite transporters, massive gene transfer to the nucleus, development of specific translocases for the re-import of endosymbiont proteins, etc. are discussed in individual chapters. Experts, dealing with biochemical, genetic and bioinformatic approaches provide insight into the state of the art of one of the central themes of biology. The book is written for graduate students, postdocs and scientists working in evolutionary biology, phycology, and phylogenetics.

This volume is based on a FEMS Symposium entitled "Bacterial Growth and Lysis: Metabolism and Structure of the Bacterial Sacculus" held at the Monastery of Lluc (Mallorca, Spain) on 5-10 April, 1992. The goals of the symposium were to assess the present state of knowledge on the structure and physiology of the bacterial murein sacculus, and to develop new hypotheses and strategies to promote further development of the field. Consequently, the contributions compiled in this volume include broadly different approaches, from the introduction of new analytical methods to the presentation of provocative models for cell wall growth and division. Structural, biochemical, and genetic aspects are widely covered with special emphasis on the enzymology and regulation of murein hydrolases (autolysins). Comprehensive reviews on bacterial S layers and yeast cell walls are included to stimulate conceptual cross-feeding with these closely related topics. We believe that this book will provide the reader with a useful and up-to-date review of the topic. We would feel deeply rewarded by any positive influence this book may have on the future progress of the field, whereby all the scientific credit for it should be given to the authors of the excellent contributions presented.

This book contains the Proceedings of the Ninth International Symposium on Pho- totrophic Prokaryotes (IXth ISPP) which was held in Vienna, Austria, from September 6-12,1997. In 1973, the far-sighted efforts of Gerhart Drews, Roger Y. Stanier, and Nor- bert Pfennig launched the first ISPP as a joint forum for scientific discussion of all aspects of research on phototrophic prokaryotes, both anoxygenic and oxygenic (cyanobacteria or blue-green algae). The ISPP International Scientific Committee, a rather loose community of scientists (see page vii for a list of current members), has since been responsible for the organization of the ISPPs on a triennial basis, without any dedicated financial support from a society, membership fees, or similar. The success of the ISPPs is therefore due to the continued enthusiasm of the scientific community for such a forum, as exemplified by the rise in attendance from 79 (1 st ISPP) to more than 400 active scientists (plus depen- dants) from all five continents in Vienna. Comparing the Book of Abstracts of 1973 with that of 1997 reflects the tremendous change that has occurred in the last 25 years in scien- tific research on phototrophic prokaryotes. Two noteworthy examples of such change are the significant shift in emphasis from anoxyphototrophs to cyanobacteria and the advent of molecular genetics, culminating at the 9th ISPP in the first complete genomic DNA se- quence of a phototrophic prokaryote, viz. the cyanobacterium Synechocystis sp. PCC6803.