Title - Foreword - Contents - List of Authors

Abstract

The two bacterial genera, Cytophaga and Flavobacterium, account for many of the yellow or orange pigmented, gram-negative bacteria which we isolate from natural and man-made environments. However, their taxonomy is far from being clear. This is very unsatisfactory, particularly as many of these bacteria are of considerable practical importance, appearing quite regularly in the clinical laboratory, or playing a role as spoilage organisms in the food industry, as fish-pathogens, or as producers of interesting enzymes and antibiotics. Last but not least, enormous populations of these organisms live in soil, freshwater, and marine environments, and are undoubtedly greatly involved in the degradation and turnover of organic substrates in nature, as well as in sewage plants. Both "genera" comprise rod-shaped, heterotrophic, primarily aerobic bacteria, which, in the case of the cytophagas move by gliding, while the flavobacteria are either immotile or flagellated. As a result of the research of the past 15 years we can today be sure that both groups are taxonomically heterogeneous. Somewhat unexpectedly, observations came to the light which suggested connections, perhaps even relatively close ones, between some of the flavobacteria with a low DNA base ratio (30 to 40 mol % GtC) and respective Cytophaga-like bacteria (CLB). This meeting has been organized by us, together with Dr. D. Claus from the DSM (German Collection of Microorganisms) in Gdttingen to discuss these new developments. Some of the more impressive data which would indicate a relationship between flavobacteria and CLB are presented in this volume, e.g. studies on the distribution among these organisms of lipoquinones, hydroxy fatty acids, and flexirubin-type pigments. Reports on unusual cellular constituents, like sphingolipids or sulfonolipids, in some of these bacteria should stimulate investigation into the occurrence of such compounds in other representatives of this group and might provide valuable additional indications of a relationship. Of course, further problems still remain to be solved. Thus, it is not yet apparent how the new genera, Cytophaga and Flavobacterium, should be delimitated and defined, nor how to proceed with the remaining organisms, e.g. the "flavobacteria" with a high G+C content (60 to 70 mol %). As can be seen from the contributions of this symposium, lively discussions ‘take place about such questions, but there is neither universal agreement yet, nor are there always sufficient available data to enable the taxonomic problems to be dealt with competently. There are actually large areas in the taxonomy of flavobacteria and CLB, where we are still only at the start. Modern taxonomic methods, like those offered by molecular biology, or the chemosystematic approach, as applied more recently to this difficult group of bacteria, promise progress in the near future. It is our opinion that this symposium has provided a good survey of the state of the taxonomy of flavobacteria and CLB, and we hope that it will stimulate further research. We should like to take the opportunity to thank all those persons who helped to make this symposium possible. The directors of the GBF, Prof. Dr. K. Kieslich and Dr. H. Zeitträger, were in favor of our enterprise from the very beginning, and allowed us to use the lecture room as well as the facilities of the institute. They also gave us essential financial support. R. Radloff solved most of the organizational problems, and Karin Rahn typed many letters in connection with the symposium and had much work with the articles for this proceedings volume. Dr. J.H. Walsdorff gave valuable assistance in compiling and editing this volume.