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The International Journal of... 2019The well-orchestrated multicellular life cycle of Dictyostelium discoideum has fascinated biologists for over a century. Self-organisation of its amoebas into... (Review)
Review
The well-orchestrated multicellular life cycle of Dictyostelium discoideum has fascinated biologists for over a century. Self-organisation of its amoebas into aggregates, migrating slugs and fruiting structures by pulsatile cAMP signalling and their ability to follow separate differentiation pathways in well-regulated proportions continue to be topics under investigation. A striking aspect of D. discoideum development is the recurrent use of cAMP as chemoattractant, differentiation inducing signal and second messenger for other signals that control the developmental programme. D. discoideum is one of >150 species of Dictyostelia and aggregative life styles similar to those of Dictyostelia evolved many times in eukaryotes. Here we review experimental studies investigating how phenotypic complexity and cAMP signalling co-evolved in Dictyostelia. In addition, we summarize comparative genomic studies of multicellular Dictyostelia and unicellular Amoebozoa aimed to identify evolutionary conservation and change in all genes known to be essential for D. discoideum development.
Topics: Biological Evolution; Cell Differentiation; Cyclic AMP; Dictyostelium; Gene Expression Regulation; Genome; Genomics; Phenotype; Phylogeny; Protein Domains; Signal Transduction
PubMed: 31840775
DOI: 10.1387/ijdb.190108ps -
Current Biology : CB Jun 2019Cooperation has been essential to the evolution of biological complexity, but many societies struggle to overcome internal conflicts and divisions. Dictyostelium... (Review)
Review
Cooperation has been essential to the evolution of biological complexity, but many societies struggle to overcome internal conflicts and divisions. Dictyostelium discoideum, or the social amoeba, has been a useful model system for exploring these conflicts and how they can be resolved. When starved, these cells communicate, gather into groups, and build themselves into a multicellular fruiting body. Some cells altruistically die to form the rigid stalk, while the remainder sit atop the stalk, become spores, and disperse. Evolutionary theory predicts that conflict will arise over which cells die to form the stalk and which cells become spores and survive. The power of the social amoeba lies in the ability to explore how cooperation and conflict work across multiple levels, ranging from proximate mechanisms (how does it work?) to ultimate evolutionary answers (why does it work?). Recent studies point to solutions to the problem of ensuring fairness, such as the ability to suppress selfishness and to recognize and avoid unrelated individuals. This work confirms a central role for kin selection, but also suggests new explanations for how social amoebae might enforce cooperation. New approaches based on genomics are also enabling researchers to decipher for the first time the evolutionary history of cooperation and conflict and to determine its role in shaping the biology of multicellular organisms.
Topics: Biological Evolution; Dictyostelium; Microbial Interactions
PubMed: 31163162
DOI: 10.1016/j.cub.2019.04.022 -
Current Biology : CB Dec 2010
Topics: Animals; Chemotaxis; Dictyostelium; Research Design; Soil Microbiology
PubMed: 21145012
DOI: 10.1016/j.cub.2010.09.051 -
The International Journal of... 2019The social amoeba Dictyostelium discoideum is a tractable model organism to study cellular allorecognition, which is the ability of a cell to distinguish itself and its... (Review)
Review
The social amoeba Dictyostelium discoideum is a tractable model organism to study cellular allorecognition, which is the ability of a cell to distinguish itself and its genetically similar relatives from more distantly related organisms. Cellular allorecognition is ubiquitous across the tree of life and affects many biological processes. Depending on the biological context, these versatile systems operate both within and between individual organisms, and both promote and constrain functional heterogeneity. Some of the most notable allorecognition systems mediate neural self-avoidance in flies and adaptive immunity in vertebrates. D. discoideum's allorecognition system shares several structures and functions with other allorecognition systems. Structurally, its key regulators reside at a single genomic locus that encodes two highly polymorphic proteins, a transmembrane ligand called TgrC1 and its receptor TgrB1. These proteins exhibit isoform-specific, heterophilic binding across cells. Functionally, this interaction determines the extent to which co-developing D. discoideum strains co-aggregate or segregate during the aggregation phase of multicellular development. The allorecognition system thus affects both development and social evolution, as available evidence suggests that the threat of developmental cheating represents a primary selective force acting on it. Other significant characteristics that may inform the study of allorecognition in general include that D. discoideum's allorecognition system is a continuous and inclusive trait, it is pleiotropic, and it is temporally regulated.
Topics: Adaptive Immunity; Cell Adhesion; Chemotaxis; Dictyostelium; Glycoproteins; Glycosylation; Ligands; Models, Biological; Phenotype; Protozoan Proteins
PubMed: 31840777
DOI: 10.1387/ijdb.190239gs -
Current Opinion in Biotechnology Oct 2022The identification of novel platform organisms for the production and discovery of small molecules is of high interest for the pharmaceutical industry. In particular,... (Review)
Review
The identification of novel platform organisms for the production and discovery of small molecules is of high interest for the pharmaceutical industry. In particular, the structural complexity of most natural products with therapeutic potential restricts an industrial production since chemical syntheses often require complex multistep routes. The amoeba Dictyostelium discoideum can be easily cultivated in bioreactors due to its planktonic growth behavior and contains numerous polyketide and terpene synthase genes with only a few compounds being already elucidated. Hence, the amoeba both bears a wealth of hidden natural products and allows for the development of new bioprocesses for existing pharmaceuticals. In this mini review, we present D. discoideum as a novel platform for the production of complex secondary metabolites and discuss its suitability for industrial processes. We also provide initial insights into future bioprocesses, both involving bacterial coculture setups and for the production of plant-based pharmaceuticals.
Topics: Amoeba; Bacteria; Biological Products; Dictyostelium; Pharmaceutical Preparations
PubMed: 35944344
DOI: 10.1016/j.copbio.2022.102766 -
Autophagy Aug 2010The use of simple organisms to understand the molecular and cellular function of complex processes is instrumental for the rapid development of biomedical research. A... (Review)
Review
The use of simple organisms to understand the molecular and cellular function of complex processes is instrumental for the rapid development of biomedical research. A remarkable example has been the discovery in S. cerevisiae of a group of proteins involved in the pathways of autophagy. Orthologues of these proteins have been identified in humans and experimental model organisms. Interestingly, some mammalian autophagy proteins do not seem to have homologues in yeast but are present in Dictyostelium, a social amoeba with two distinctive life phases, a unicellular stage in nutrient-rich conditions that differentiates upon starvation into a multicellular stage that depends on autophagy. This review focuses on the identification and annotation of the putative Dictyostelium autophagy genes and on the role of autophagy in development, cell death and infection by bacterial pathogens.
Topics: Animals; Autophagy; Cell Death; Dictyostelium; Evolution, Molecular; Genes, Protozoan; Models, Biological; Signal Transduction
PubMed: 20603609
DOI: 10.4161/auto.6.6.12513 -
Current Issues in Molecular Biology Jul 2006The 34 Mb genome of Dictyostelium discoideum is carried on 6 chromosomes and has been fully sequenced by an international consortium. The sequence was assembled on the... (Review)
Review
The 34 Mb genome of Dictyostelium discoideum is carried on 6 chromosomes and has been fully sequenced by an international consortium. The sequence was assembled on the classical and physical maps that had been built up over the years and refined by HAPPY mapping. Annotation of the sequence predicted about 12,000 genes for proteins of at least 50 amino acids in length. The total number of amino acids encoded (the proteome) is more than double that in yeast and rivals that of metazoans. The genome sequence shows all the proteins available to Dictyostelium as well as definitively showing which domains have been lost since Dictyostelium diverged from the line leading to metazoans. Genomics opens the door to determining the expression patterns of all the genes during growth and development using microarrays. This approach has already uncovered a wealth of new markers for the stages of development and the various cell types. Transcription factors and their cis-regulatory sites that account for the surprising complexity of Dictyostelium development can be analyzed much more easily now that we have the complete sequence.
Topics: Animals; Chromosomes; Dictyostelium; Genome, Protozoan; Transcription, Genetic
PubMed: 16875414
DOI: No ID Found -
The International Journal of... 2019The social amoeba Dictyostelium discoideum has provided considerable insight into the evolution of cooperation and conflict. Under starvation, D. discoideum amoebas... (Review)
Review
The social amoeba Dictyostelium discoideum has provided considerable insight into the evolution of cooperation and conflict. Under starvation, D. discoideum amoebas cooperate to form a fruiting body comprised of hardy spores atop a stalk. The stalk development is altruistic because stalk cells die to aid spore dispersal. The high relatedness of cells in fruiting bodies in nature implies that this altruism often benefits relatives. However, since the fruiting body forms through aggregation there is potential for non-relatives to join the aggregate and create conflict over spore and stalk fates. Cheating is common in chimeras of social amoebas, where one genotype often takes advantage of the other and makes more spores. This social conflict is a significant force in nature as indicated by rapid rates of adaptive evolution in genes involved in cheating and its resistance. However, cheating can be prevented by high relatedness, allorecognition via tgr genes, pleiotropy and evolved resistance. Future avenues for the study of cooperation and conflict in D. discoideum include the sexual cycle as well as the relationship between D. discoideum and its bacterial symbionts. D. discoideum's tractability in the laboratory as well as its uncommon mode of aggregative multicellularity have established it as a promising model for future studies of cooperation and conflict.
Topics: Altruism; Biological Evolution; Dictyostelium; Genetic Variation; Genetics, Population; Genotype; Models, Biological; Reproduction; Selection, Genetic; Spores, Protozoan
PubMed: 31840776
DOI: 10.1387/ijdb.190158jm -
Traffic (Copenhagen, Denmark) May 2001Phagocytosis and macropinocytosis are actin-dependent clathrin-independent processes primarily performed by cells like neutrophils and macrophages that result in the... (Review)
Review
Phagocytosis and macropinocytosis are actin-dependent clathrin-independent processes primarily performed by cells like neutrophils and macrophages that result in the internalization of particles or the formation of fluid-filled macropinosomes, respectively. Phagocytosis consists of a number of stages, including attachment of particles to cell surface receptors, engulfment of the particle dependent on actin polymerization and membrane exocytosis, and formation of phago-lysosomes. In contrast, the molecular steps regulating macropinocytosis are only just now being deciphered. Much remains to be learned concerning the signaling pathways that regulate these processes. Dictyostelium is a genetically and biochemically tractable professional phagocyte that has proven to be a powerful system with which to determine the nature of the molecular steps involved in regulating these internalization processes. This review summarizes what is currently understood concerning the molecular mechanisms governing phagocytosis and macropinocytosis in Dictyostelium and describes recent data concerning the common and distinct pathways that regulate these processes.
Topics: Animals; Dictyostelium; Phagocytosis; Phosphatidylinositols; Pinocytosis
PubMed: 11350627
DOI: 10.1034/j.1600-0854.2001.002005311.x -
Eukaryotic Cell Feb 2011Much remains to be understood about how a group of cells break symmetry and differentiate into distinct cell types. The simple eukaryote Dictyostelium discoideum is an... (Review)
Review
Much remains to be understood about how a group of cells break symmetry and differentiate into distinct cell types. The simple eukaryote Dictyostelium discoideum is an excellent model system for studying questions such as cell type differentiation. Dictyostelium cells grow as single cells. When the cells starve, they aggregate to develop into a multicellular structure with only two main cell types: spore and stalk. There has been a longstanding controversy as to how a cell makes the initial choice of becoming a spore or stalk cell. In this review, we describe how the controversy arose and how a consensus developed around a model in which initial cell type choice in Dictyostelium is dependent on the cell cycle phase that a cell happens to be in at the time that it starves.
Topics: Animals; Cell Cycle; Cell Differentiation; Dictyostelium; Gene Expression Profiling; Neutral Red; Spores, Protozoan; Staining and Labeling; Starvation
PubMed: 21148754
DOI: 10.1128/EC.00219-10