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The SAS Genes: Functionally Distinct Members of the YPT1/SEC4 Family in Dictyostelium
Published in Juan Carlos Lacal, Frank McCormick, The ras Superfamily of GTPases, 2017
Alan R. Kimmel, Tracy Ruscelli, James Cardelli
Dictyostelium discoideum grows as a unicellular, ameboid organism. When cells exhaust their food supply, they initiate a developmental program which leads to the formation of a multicellular aggregate comprised of distinct, non-dividing cell types.1,2 These cells, organized through morphogenetic movement and cell sorting, are nonterminally differentiated prestalk and prespore cells, the precursors to the terminally differentiated stalk and spore cells found in the fully mature fruiting body at the culmination of development.1 Aggregation, differentiation, and cell sorting are directed by secreted (extracellular) cAMP which serves as both a chemoattractant and a hormone-like, primary signaling molecule.2
Pseudomonas aeruginosa
Published in Dongyou Liu, Laboratory Models for Foodborne Infections, 2017
Stavria Panayidou, Yiorgos Apidianakis
Dictyostelium discoideum is a slime mould109 with two remarkable multistage life cycles.110,111 One is the asexual cycle, known as social cycle, characterized by the formation of fruiting bodies that release spores.110,112 Spores give rise to haploid amoebae, which need to feed on bacteria to undergo mitosis.110 Starving amoebas aggregate, forming new fruiting bodies. If starvation is combined with darkness and humidity, the sexual cycle starts with the fusion of two haploid amoebas of the opposite mate types, which attract and cannibalize surrounding cells forming a macrocyst that releases recombined new amoebas.110,113Dictyostelium cells naturally live in forest soil, and, by obligingly feeding on bacteria, they can be a natural host of pathogenic bacteria. Thus, they can serve as a great model organism for studying the mechanisms of bacteria–phagocyte interaction. Indeed, D. discoideum has been used to investigate the virulence of many human bacterial pathogens, including P. aeruginosa.114 For example, the wild-type P. aeruginosa strain PAO1 inhibits D. discoideum growth, while rhl quorum-sensing system is required for full virulence.115 Interestingly, the P. aeruginosa strain PA14 is more virulent than PAO1 against D. discoideum.116 This is probably because 169 genes are differentially expressed between the 2 strains.116 Of note, a random mutagenesis screen of the P. aeruginosa strain 22D10 identified anthranilate phosphoribosyltransferase gene trpD to be important for quorum-sensing function and the siderophore pyochelin genes pchH and pchI for the induction of the type III secretion system. Importantly, trpD, pchH, and pchI mutants are also attenuated in virulence in the Drosophila pricking and feeding assays and the mouse lung acute infection assay.117
Structure, function and disease relevance of Wnt inhibitory factor 1, a secreted protein controlling the Wnt and hedgehog pathways
Published in Growth Factors, 2019
Krisztina Kerekes, László Bányai, Mária Trexler, László Patthy
So far no Wnts or Hhs have been described from fungi, plants or unicellular eukaryotes, suggesting that the fusion of their constituent domains occurred in Metazoa (Adamska et al. 2007b; Bazan, Janda, and Garcia 2012). Although the Wnt and Hh signaling pathways appear to be inventions of Metazoa it is possible to identify some components of these signaling pathways in protozoa (Holstein 2012). Several Frizzled/SMO-like genes have been described in the social ameba Dictyostelium discoideum. Sixteen of these encode cysteine-rich Fz domain, indicating that the domain architecture typical of Frizzled/SMO receptors arose prior to the emergence of Metazoa (Harwood 2008). Orthologs of the Wnt co-receptor proteins LRP5/6, however, are apparently missing from these slime molds (Eichinger et al. 2005; Prabhu and Eichinger 2006).
Extracellular vesicles-based drug delivery system for cancer treatment
Published in Cogent Medicine, 2019
Banuja Balachandran, Yuana Yuana
Non-mammalian eukaryotes such as (edible) plants and the non-pathogenic amoeba Dictyostelium discoideum are potential EV donors (Ju et al., 2013; Lavialle et al., 2009; Perez-Bermudez, Blesa, Soriano, & Marcilla, 2016; Tatischeff, Larquet, Falcon-Perez, Turpin, & Kruglik, 2012; Wang et al., 2014). EVs isolated from edible plant extracts also have drawn lots of attention as drug nanocarriers as it can overcome the safety and delivery requirements (Perez-Bermudez et al., 2016). EVs could be isolated from grape juice and pulp of grapefruit skin. These EVs can be taken up by intestinal macrophages and stem cells in murine models. The inherent biocompatibility and stability at wide ranges of pH values highlight the potential of EVs from the edible plants for further development of EV-based oral delivery system (Ju et al., 2013; Wang et al., 2014). Dictyostelium cells and their EVs are non-pathogenic providing great potential as a source of therapeutic EVs. Dictyostelium cells are particularly easy to grow in vitro and produce EVs resembling EVs derived from mammalian cells and could be loaded with an anti-tumoural compound hypericin (Lavialle et al., 2009). The therapeutic potential of EVs from various sources is summarized in Table 1.
Nanoparticles as a potential teratogen: a lesson learnt from fruit fly
Published in Nanotoxicology, 2019
Bedanta Kumar Barik, Monalisa Mishra
Various studies used cell cultures to understand the underlying mechanisms of nanotoxicity (Lin et al. 2006; Long et al. 2006; Ahamed et al. 2008; AshaRani et al. 2009; Napierska et al. 2009; Asakura et al. 2010; Hackenberg et al. 2011; Bondarenko et al. 2013; de Melo Reis et al. 2015). However, a cell culture model cannot mimic the effect of NPs on an organism with respect to bio distribution, accumulation, metabolism, persistence, and its elimination. Thus, the accuracy of effect in the living organism is compromised (Hu et al. 2009). This limitation is overcome by various in vivo models which allow us to know the internalization, cellular uptake, and tissue distribution of nanoparticle in the living being (Yadav et al. 2010; Yadav et al. 2011). Among various models, mice, round worm (Caenorhabditis elegans), zebra fish (Danio rerio), Daphnia magna, Rhinellaa renarum, Xenopus laevis, Hydra, and Drosophila melanogaster are widely used to study the toxicity of NPs (Wang et al. 2008; Contreras et al. 2013; Song et al. 2012; Hunt et al. 2013; Völker et al. 2013; Chatterjee, Eom et al. 2014; Chatterjee, Yang et al. 2014; He et al. 2014; Meyer and Williams 2014; Santo et al. 2014; Dedeh et al. 2015; Ibarra et al. 2016; Murugadas et al. 2016; Webster et al. 2016; Barbero and Yslas 2017; Colombo et al. 2017; Coll et al. 2018; Lajmanovich et al. 2018). Toxicity study from various models proposes NP can alter the developmental and behavioral process in the offspring thus acts as a teratogen. All these models are used for teratogenic testing predominantly (Coyle et al. 1976; Bailey et al. 2013; Almeida et al. 2016). Primitive animal such as Dictyostelium discoideum is also used for tertogenicity testing (Maeda 1970).