Dictyostelium discoideum is a simple but fascinating eukaryotic microorg- ism, whose natural habitat is deciduous forest soil and decaying leaves, where the amoebae feed on bacteria and grow as independent single cells. Exhaustion of the bacterial food source triggers a developmental program, in which up to 100,000 cells aggregate by chemotaxis towards cAMP. Morphogenesis and cell different- tion then culminate in the production of spores enabling the organism to survive unfavorable conditions. Dictyostelium offers unique advantages for studying f- damental cellular processes with the aid of powerful molecular genetic, bioche- cal, and cell biological tools. These processes include signal transduction, chemotaxis, cell motility, cytokinesis, phagocytosis, and aspects of development such as cell sorting, pattern formation and cell type differentiation. Recently, D- tyostelium was also described as a suitable host for pathogenic bacteria in which one can conveniently study the process of infection. In addition, Dictyostelium has many of the experimental conveniences of Saccharomyces cerevisiae and is pr- ably the best experimentally manipulatable protozoan, providing insight into this diverse group of organisms, which includes some of the most dangerous human parasites. The recent completion of the Dictyostelium genome sequencing project strengthens the position of D. discoideum as a model organism. The completed genome sequence and other valuable community resources constitute the source for basic biological and biomedical research and for genome-wide analyses.

Dictyostelia are soil amoebae capable of extraordinary feats of survival, motility, chemotaxis, and development. Characterised by their ability to transform from a single-celled organism into an elaborate assemblage of thousands of synchronously-moving cells, Dictyostelids are often referred to as 'social amoebae', and have been the subjects of serious study since the 1930s. Research in this area has been instrumental in understanding many problems in cellular biology. Beginning with the history of Dictyostelids and discussing each stage of their development, this book considers the evolution of this unique organism, analyses the special properties of the Dictyostelid genome, and presents in detail the methods available, at the time of the book's original publication in 2001, to manipulate their genes. Representing the synthesis of such material and with an emphasis on combining classical experiments with modern molecular findings, this book will be essential for researchers and graduates in developmental and cellular biology.

Dictyostelium Discoideum: A Developmental System presents D. discoideum as a model eukaryotic system to study a variety of developmental problems. The book describes the life cycle of the organism D. discoideum which exists in nature as a soil amoeba in forest detritus. The nuclei of D. discoideum contain DNA, RNA, and proteins which have properties similar to those of histones present in calf thymus nuclei. The unique sequences of the genome of the organism code for the gene products synthesize during its growth and development. One approach in genetic analyses to understanding the developmental processes of the organism is to isolate a large number of morphological mutants. The isolation process will indicate the number of variations that are open to the developing system, and will point to causal connections between stages. The text also explains that the number of cells which differentiate into stalk cells is the result of timing and mechanics of the process of culmination. Ashworth (1971) suggests that cells in pseudoplasmodia of D. discoideum adjust their positions in relation to the chemical structure of the sheath itself. A model shows how cells communicate their response to the sheath in an axial fashion. The book can prove beneficial for biochemists, micro-biologists, cellular researchers, and investigators involved in the study of cellular biology.

Since their discovery in 1869, the dictyostelids have attracted the attention of scientists in a wide variety of fields. This interest has stemmed from their peculiar lifestyle and developmental properties, which were shaped by the evolutionary forces that generated multicellularity during eukaryotic evolution. More recently, the dictyostelids have gained attention due to the striking similarities found at the genomic, cellular and biochemical levels with human cells, which has propelled the species Dictyostelium discoideum to become a model system for biology and medicine in many laboratories. This book covers the latest advances in our knowledge of these extraordinary organisms with topics spanning from their evolutionary history, ecology and diversity to the recent discoveries regarding their cellular and molecular biology.

The Development Of Dictyostelium Discoideum ...

As 1 review these pages, the last of them written in Summer 1978, some retrospec tive thoughts come to mind which put the whole business into better perspective for me and might aid the prospective reader in choosing how to approach this volume. The most conspicuous thought in my mind at present is the diversity of wholly independent explorations that came upon phase singularities, in one guise or another, during the past decade. My efforts to gather the published literature during the last phases of actually writing a whole book about them were almost equally divided between libraries of Biology, Chemistry, Engineering, Mathematics, Medicine, and Physics. A lot of what 1 call "gathering " was done somewhat in anticipation in the form of cönjecture, query, and prediction based on analogy between developments in different fields. The consequence throughout 1979 was that our long-suffering publisher re peatedly had to replace such material by citation of unexpected flurries of papers giving substantive demonstration. 1 trust that the authors of these many excellent reports, and especially of those I only found too late, will forgive the brevity of allusion I feIt compelled to observe in these substitutions. A residue of loose ends is largely collected in the index under "QUERIES. " It is c1ear to me already that the materials I began to gather several years ago represented only the first flickering of what turns out to be a substantial conflagration.