-
Scientific Reports Mar 2019Dictyostelium discoideum (D.d.) is a widely studied amoeba due to its capabilities of development, survival, and self-organization. During aggregation it produces and...
Dictyostelium discoideum (D.d.) is a widely studied amoeba due to its capabilities of development, survival, and self-organization. During aggregation it produces and relays a chemical signal (cAMP) which shows spirals and target centers. Nevertheless, the natural emergence of these structures is still not well understood. We present a mechanism for creation of centers and target waves of cAMP in D.d. by adding cell inhomogeneity to a well known reaction-diffusion model of cAMP waves and we characterize its properties. We show how stable activity centers appear spontaneously in areas of higher cell density with the oscillation frequency of these centers depending on their density. The cAMP waves have the characteristic dispersion relation of trigger waves and a velocity which increases with cell density. Chemotactically competent cells react to these waves and create aggregation streams even with very simple movement rules. Finally we argue in favor of the existence of bounded phosphodiesterase to maintain the wave properties once small cell clusters appear.
Topics: Chemotaxis; Computer Simulation; Cyclic AMP; Dictyostelium; Models, Biological; Movement; Phosphoric Diester Hydrolases; Protozoan Proteins; Signal Transduction
PubMed: 30850709
DOI: 10.1038/s41598-019-40373-4 -
Current Opinion in Genetics &... Aug 2016Dictyostelia represent a tractable system to resolve the evolution of cell-type specialization, with some taxa differentiating into spores only, and other taxa with... (Review)
Review
Dictyostelia represent a tractable system to resolve the evolution of cell-type specialization, with some taxa differentiating into spores only, and other taxa with additionally one or up to four somatic cell types. One of the latter forms, Dictyostelium discoideum, is a popular model system for cell biology and developmental biology with key signalling pathways controlling cell-specialization being resolved recently. For the most dominant pathways, evolutionary origins were retraced to a stress response in the unicellular ancestor, while modifications in the ancestral pathway were associated with acquisition of multicellular complexity. This review summarizes our current understanding of developmental signalling in D. discoideum and its evolution.
Topics: Animals; Cyclic AMP; Developmental Biology; Dictyostelium; Evolution, Molecular; Phylogeny; Signal Transduction; Stress, Physiological
PubMed: 27318097
DOI: 10.1016/j.gde.2016.05.014 -
The International Journal of... 2019The Dictyostelium discoideum model system is a powerful tool for undergraduate cell biology teaching laboratories. The cells are biologically safe, grow at room...
The Dictyostelium discoideum model system is a powerful tool for undergraduate cell biology teaching laboratories. The cells are biologically safe, grow at room temperature and it is easy to experimentally induce, observe, and perturb a breadth of cellular processes making the system amenable to many teaching lab situations and goals. Here we outline the advantages of Dictyostelium, discuss laboratory courses we teach in three very different educational settings, and provide tips for both the novice and experienced Dictyostelium researcher. With this article and the extensive sets of protocols and tools referenced here, implementing these labs, or parts of them, will be relatively straightforward for any instructor.
Topics: Biology; California; Cell Adhesion; Cell Movement; Cell Proliferation; Chemotaxis; Connecticut; Cytoskeleton; Dictyostelium; Electroporation; Endocytosis; Folic Acid; Humans; Iowa; Models, Biological; Phagocytosis; Phototaxis; Students; Teaching; Universities
PubMed: 31840792
DOI: 10.1387/ijdb.190249dk -
Journal of Biosciences Dec 2014Caspases are cysteine proteases that are important regulators of programmed cell death in animals. Two novel relatives to members of the caspase families metacaspases... (Review)
Review
Caspases are cysteine proteases that are important regulators of programmed cell death in animals. Two novel relatives to members of the caspase families metacaspases and paracaspase have been discovered. Metacaspase type-1 was identified in Acanthamoeba castellanii, an opportunistic protozoan parasite that causes severe diseases in humans. Paracaspase was found in the non-pathogenic protozoan Dictyostelium discoideum. Since their discovery in Acanthamoeba and Dictyostelium, metacaspases and paracaspases have remained poorly characterized. At present we do not have sufficient data about the molecular function of these caspase-like proteins or their role, if any, in programmed cell death. How these caspase proteins function at the molecular level is an important area of study that will provide insight into their potential for treatment therapies against Acanthamoeba infection and other similar parasitic protozoan. Additionally, finding the molecular functions of these caspase-like proteins will provide information concerning their role in more complex organisms.The aim of this article was to review recent discoveries about metacaspases and paracaspases as regulators of apoptotic and non-apoptotic processes.
Topics: Acanthamoeba castellanii; Apoptosis; Caspases; Dictyostelium; Protozoan Proteins
PubMed: 25431419
DOI: 10.1007/s12038-014-9486-0 -
The Biological Bulletin Aug 2015Protozoa are a diverse group of unicellular eukaryotes. Evidence has accumulated that protozoan aquaporin water and solute channels (AQP) contribute to adaptation in... (Review)
Review
Protozoa are a diverse group of unicellular eukaryotes. Evidence has accumulated that protozoan aquaporin water and solute channels (AQP) contribute to adaptation in changing environments. Intracellular protozoan parasites live a well-sheltered life. Plasmodium spp. express a single AQP, Toxoplasma gondii two, while Trypanosoma cruzi and Leishamnia spp. encode up to five AQPs. Their AQPs are thought to import metabolic precursors and simultaneously to dispose of waste and to help parasites survive osmotic stress during transmission to and from the insect vector or during kidney passages. Trypanosoma brucei is a protozoan parasite that swims freely in the human blood. Expression and intracellular localization of the three T. brucei AQPs depend on the stage of differentiation during the life cycle, suggesting distinct roles in energy generation, metabolism, and cell motility. Free-living amoebae are in direct contact with the environment, encountering severe and sudden changes in the availability of nutrition, and in the osmotic conditions due to rainfall or drought. Amoeba proteus expresses a single AQP that is present in the contractile vacuole complex required for osmoregulation, whereas Dictyostelium discoideum expresses four AQPs, of which two are present in the single-celled amoeboidal stage and two more in the later multicellular stages preceding spore formation. The number and regulation of protozoan aquaporins may reflect environmental complexity. We highlight the gated AqpB from D. discoideum as an example of how life in the wild is challenged by a complex AQP structure-function relationship.
Topics: Aquaporins; Dictyostelium; Environment; Eukaryota; Gene Expression Regulation; Water-Electrolyte Balance
PubMed: 26338868
DOI: 10.1086/BBLv229n1p38 -
Advances in Experimental Medicine and... 2016Besides the most established expression hosts, several eukaryotic microorganisms and filamentous fungi have also been successfully used as platforms for the production... (Review)
Review
Besides the most established expression hosts, several eukaryotic microorganisms and filamentous fungi have also been successfully used as platforms for the production of foreign proteins. Filamentous fungi and Dictyostelium discoideum are two prominent examples. Filamentous fungi, typically Aspergillus and Trichoderma, are usually employed for the industrial production of enzymes and secondary metabolites for food processing, pharmaceutical drugs production, and textile and paper applications, with multiple products already accepted for their commercialization. The low cost of culture medium components, high secretion capability directly to the extracellular medium, and the intrinsic ability to produce post-translational modifications similar to the mammalian type, have promoted this group as successful hosts for the expression of proteins, including examples from phylogenetically distant groups: humans proteins such as IL-2, IL-6 or epithelial growth factor; α-galactosidase from plants; or endoglucanase from Cellulomonas fimi, among others. D. discoideum is a social amoeba that can be used as an expression platform for a variety of proteins, which has been extensively illustrated for cytoskeletal proteins. New vectors for heterologous expression in D. discoideum have been recently developed that might increase the usefulness of this system and expand the range of protein classes that can be tackled. Continuous developments are ongoing to improve strains, promoters, production and downstream processes for filamentous fungi, D. discoideum, and other alternative eukaryotic hosts. Either for the overexpression of individual genes, or in the coexpression of multiples genes, this chapter illustrates the enormous possibilities offered by these groups of eukaryotic organisms.
Topics: Animals; Dictyostelium; Fungal Proteins; Fungi; Gene Expression Regulation, Fungal; Genetic Vectors; Humans; Multiprotein Complexes; Protein Engineering; Protein Multimerization; Protein Processing, Post-Translational; Protein Structure, Quaternary; Protein Subunits; Protozoan Proteins; Recombinant Proteins; Structure-Activity Relationship; Transcription, Genetic
PubMed: 27165325
DOI: 10.1007/978-3-319-27216-0_11 -
PLoS Computational Biology Aug 2021Navigation of fast migrating cells such as amoeba Dictyostelium and immune cells are tightly associated with their morphologies that range from steady polarized forms... (Comparative Study)
Comparative Study
Navigation of fast migrating cells such as amoeba Dictyostelium and immune cells are tightly associated with their morphologies that range from steady polarized forms that support high directionality to those more complex and variable when making frequent turns. Model simulations are essential for quantitative understanding of these features and their origins, however systematic comparisons with real data are underdeveloped. Here, by employing deep-learning-based feature extraction combined with phase-field modeling framework, we show that a low dimensional feature space for 2D migrating cell morphologies obtained from the shape stereotype of keratocytes, Dictyostelium and neutrophils can be fully mapped by an interlinked signaling network of cell-polarization and protrusion dynamics. Our analysis links the data-driven shape analysis to the underlying causalities by identifying key parameters critical for migratory morphologies both normal and aberrant under genetic and pharmacological perturbations. The results underscore the importance of deciphering self-organizing states and their interplay when characterizing morphological phenotypes.
Topics: Animals; Cell Movement; Cell Polarity; Cell Shape; Cell Surface Extensions; Cells, Cultured; Cichlids; Computational Biology; Computer Simulation; Deep Learning; Dictyostelium; Fibroblasts; HL-60 Cells; Humans; Models, Biological
PubMed: 34383753
DOI: 10.1371/journal.pcbi.1009237 -
Secreted Cyclic Di-GMP Induces Stalk Cell Differentiation in the Eukaryote Dictyostelium discoideum.Journal of Bacteriology Jan 2016Cyclic di-GMP (c-di-GMP) is currently recognized as the most widely used intracellular signal molecule in prokaryotes, but roles in eukaryotes were only recently... (Review)
Review
Cyclic di-GMP (c-di-GMP) is currently recognized as the most widely used intracellular signal molecule in prokaryotes, but roles in eukaryotes were only recently discovered. In the social amoeba Dictyostelium discoideum, c-di-GMP, produced by a prokaryote-type diguanylate cyclase, induces the differentiation of stalk cells, thereby enabling the formation of spore-bearing fruiting bodies. In this review, we summarize the currently known mechanisms that control the major life cycle transitions of Dictyostelium and focus particularly on the role of c-di-GMP in stalk formation. Stalk cell differentiation has characteristics of autophagic cell death, a process that also occurs in higher eukaryotes. We discuss the respective roles of c-di-GMP and of another signal molecule, differentiation-inducing factor 1, in autophagic cell death in vitro and in stalk formation in vivo.
Topics: Cyclic GMP; Dictyostelium; Signal Transduction; Spores, Protozoan
PubMed: 26013485
DOI: 10.1128/JB.00321-15 -
Cell Biochemistry and Function Dec 2023Nutrient-sensing plays a crucial role in maintaining cellular energy and metabolic homeostasis. Perturbations in sensing pathways are associated with a wide variety of...
Nutrient-sensing plays a crucial role in maintaining cellular energy and metabolic homeostasis. Perturbations in sensing pathways are associated with a wide variety of pathologies, especially metabolic diseases. Very little is understood about sensing fluctuations in nutrients and how this information is integrated into physiological and metabolic adaptation that could further affect cell-fate decisions during differentiation in Dictyostelium discoideum (henceafter, Dictyostelium). Glucose is the primary metabolic fuel among all nutrients. Carbohydrates, lipids and proteins ultimately breakdown into glucose, which is further used for providing energy. The maintenance of optimum glucose levels is important for efficient cell-survival. Glucose is not only a nutrient, but also a signaling molecule influencing cell growth and differentiation in Dictyostelium. Modulation of endogenous glucose levels either by varying exogenous glucose levels or genetic overexpression or deletion of genes involved in glucose signaling lead to changes in endogenous metabolite levels such as ADP/ATP ratio, NAD /NADH ratio, cAMP and ROS levels which further influence cell-fate decisions. Here, we show that AMPKα and Sir2D are components of glucose-signaling pathway in Dictyostelium which adjust cell metabolism interdependently in response to nutrient-status and promote cell-fate decisions.
Topics: Dictyostelium; Signal Transduction; Cell Differentiation; Cell Cycle; Glucose
PubMed: 38014740
DOI: 10.1002/cbf.3892 -
FEBS Open Bio Jun 2020Copines are a family of cytosolic proteins that associate with membranes in a calcium-dependent manner and are found in many eukaryotic organisms....
Copines are a family of cytosolic proteins that associate with membranes in a calcium-dependent manner and are found in many eukaryotic organisms. Dictyostelium discoideum has six copine genes (cpnA-cpnF), and cells lacking cpnA(cpnA ) have defects in cytokinesis, chemotaxis, adhesion, and development. CpnA has also been shown to associate with the plasma membrane, contractile vacuoles (CV), and organelles of the endolysosomal pathway. Here, we use cpnA cells to investigate the role of CpnA in CV function and endocytosis. When placed in water, cpnA cells made abnormally large CVs that took longer to expel. Visualization of CVs with the marker protein GFP-dajumin indicated that cpnA cells had fewer CVs that sometimes refilled before complete emptying. In endocytosis assays, cpnA cells took up small fluorescent beads by macropinocytosis at rates similar to parental cells. However, cpnA cells reached a plateau sooner than parental cells and had less fluorescence at later time points. p80 antibody labeling of postlysosomes (PL) indicated that there were fewer and smaller PLs in cpnA cells. In dextran pulse-chase experiments, the number of PLs peaked earlier in cpnA cells, and the PLs did not become as large and disappeared sooner as compared to parental cells. PLs in cpnA cells were also shown to have more actin coats, suggesting CpnA may play a role in actin filament disassembly on PL membranes. Overall, these results indicate that CpnA is involved in the regulation of CV size and expulsion, and the maturation, size, and exocytosis of PLs.
Topics: Carrier Proteins; Cell Line; Cell Membrane; Chemotaxis; Dictyostelium; Exocytosis; Gene Knockout Techniques; Genes, Reporter; Green Fluorescent Proteins; Intravital Microscopy; Microscopy, Fluorescence; Protozoan Proteins; Time-Lapse Imaging; Vacuoles
PubMed: 32351039
DOI: 10.1002/2211-5463.12874