The Amoebozoa

Schilde, Christina; Schaap, Pauline

doi:10.1007/978-1-62703-302-2_1

Cited by 28 publications

(19 citation statements)

References 76 publications

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“…Both genera Polysphondylium and Dictyostelium belong to the family Dictyosteliidae, whereas A. subglobosum is a species in the Actyosteliidae family. Both Dictyosteliidae and Actyosteliidae belong to the same order of Dictyosteliida (18). It should be noted that all of the six eukaryotic species that were found to contain TPS genes in this study are amoebae (19), with the five species from Dictyosteliida belonging to the unique group of multicellular social amoebae (18).…”

Section: Identification Of Terpene Synthase Genes In Nonplant/nonfungusmentioning

confidence: 66%

Terpene synthase genes in eukaryotes beyond plants and fungi: Occurrence in social amoebae

Chen

Köllner

Jia

et al. 2016

Proc. Natl. Acad. Sci. U.S.A.

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Terpenes are structurally diverse natural products involved in many ecological interactions. The pivotal enzymes for terpene biosynthesis, terpene synthases (TPSs), had been described only in plants and fungi in the eukaryotic domain. In this report, we systematically analyzed the genome sequences of a broad range of nonplant/ nonfungus eukaryotes and identified putative TPS genes in six species of amoebae, five of which are multicellular social amoebae from the order of Dictyosteliida. A phylogenetic analysis revealed that amoebal TPSs are evolutionarily more closely related to fungal TPSs than to bacterial TPSs. The social amoeba Dictyostelium discoideum was selected for functional study of the identified TPSs. D. discoideum grows as a unicellular organism when food is abundant and switches from vegetative growth to multicellular development upon starvation. We found that expression of most D. discoideum TPS genes was induced during development. Upon heterologous expression, all nine TPSs from D. discoideum showed sesquiterpene synthase activities. Some also exhibited monoterpene and/or diterpene synthase activities. Direct measurement of volatile terpenes in cultures of D. discoideum revealed essentially no emission at an early stage of development. In contrast, a bouquet of terpenes, dominated by sesquiterpenes including β-barbatene and (E,E)-α-farnesene, was detected at the middle and late stages of development, suggesting a development-specific function of volatile terpenes in D. discoideum. The patchy distribution of TPS genes in the eukaryotic domain and the evidence for TPS function in D. discoideum indicate that the TPS genes mediate lineage-specific adaptations.terpene synthases | amoebae | volatiles | evolution | chemical ecology

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Section: Identification Of Terpene Synthase Genes In Nonplant/nonfungusmentioning

confidence: 66%

Terpene synthase genes in eukaryotes beyond plants and fungi: Occurrence in social amoebae

Chen

Köllner

Jia

et al. 2016

Proc. Natl. Acad. Sci. U.S.A.

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“…This notion was overturned by the identification of some tyrosine kinases outside of Opisthokonta ( Suga et al 2012 ) and the presence of 21 tyrosine kinases in A. castellanii ( Clarke et al 2013 ), a member of Lobosa, one of the two major subdivisions of Amoebozoa. P. polycephalum and D. discoideum reside in the other subdivision Conosa ( Schilde and Schaap 2013 ). The presence of tyrosine kinases in both subdivisions of Amoebozoa, in their sister group Opisthokonta, and in other eukaryote divisions indicates that tyrosine kinases were likely present in the LCA to all eukaryotes and were selectively lost from many phyla.…”

Section: Resultsmentioning

confidence: 99%

ThePhysarum polycephalumGenome Reveals Extensive Use of Prokaryotic Two-Component and Metazoan-Type Tyrosine Kinase Signaling

Schaap

Barrantes

Minx³

et al. 2015

Genome Biol Evol

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100

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Physarum polycephalum is a well-studied microbial eukaryote with unique experimental attributes relative to other experimental model organisms. It has a sophisticated life cycle with several distinct stages including amoebal, flagellated, and plasmodial cells. It is unusual in switching between open and closed mitosis according to specific life-cycle stages. Here we present the analysis of the genome of this enigmatic and important model organism and compare it with closely related species. The genome is littered with simple and complex repeats and the coding regions are frequently interrupted by introns with a mean size of 100 bases. Complemented with extensive transcriptome data, we define approximately 31,000 gene loci, providing unexpected insights into early eukaryote evolution. We describe extensive use of histidine kinase-based two-component systems and tyrosine kinase signaling, the presence of bacterial and plant type photoreceptors (phytochromes, cryptochrome, and phototropin) and of plant-type pentatricopeptide repeat proteins, as well as metabolic pathways, and a cell cycle control system typically found in more complex eukaryotes. Our analysis characterizes P. polycephalum as a prototypical eukaryote with features attributed to the last common ancestor of Amorphea, that is, the Amoebozoa and Opisthokonts. Specifically, the presence of tyrosine kinases in Acanthamoeba and Physarum as representatives of two distantly related subdivisions of Amoebozoa argues against the later emergence of tyrosine kinase signaling in the opisthokont lineage and also against the acquisition by horizontal gene transfer.

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“…Dictyostelium discoideum is a member of the Amoebozoa (Schilde and Schaap, 2013). The cells live as unicellular amoebae in deciduous forest soil, feeding on bacteria that are taken up by phagocytosis and dividing by binary fission.…”

Section: Introductionmentioning

confidence: 99%

Iron metabolism and resistance to infection by invasive bacteria in the social amoeba Dictyostelium discoideum

Bozzaro¹,

Buracco²,

Peracino³

2013

Front. Cell. Infect. Microbiol.

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Dictyostelium cells are forest soil amoebae, which feed on bacteria and proliferate as solitary cells until bacteria are consumed. Starvation triggers a change in life style, forcing cells to gather into aggregates to form multicellular organisms capable of cell differentiation and morphogenesis. As a soil amoeba and a phagocyte that grazes on bacteria as the obligate source of food, Dictyostelium could be a natural host of pathogenic bacteria. Indeed, many pathogens that occasionally infect humans are hosted for most of their time in protozoa or free-living amoebae, where evolution of their virulence traits occurs. Due to these features and its amenability to genetic manipulation, Dictyostelium has become a valuable model organism for studying strategies of both the host to resist infection and the pathogen to escape the defense mechanisms. Similarly to higher eukaryotes, iron homeostasis is crucial for Dictyostelium resistance to invasive bacteria. Iron is essential for Dictyostelium, as both iron deficiency or overload inhibit cell growth. The Dictyostelium genome shares with mammals many genes regulating iron homeostasis. Iron transporters of the Nramp (Slc11A) family are represented with two genes, encoding Nramp1 and Nramp2. Like the mammalian ortholog, Nramp1 is recruited to phagosomes and macropinosomes, whereas Nramp2 is a membrane protein of the contractile vacuole network, which regulates osmolarity. Nramp1 and Nramp2 localization in distinct compartments suggests that both proteins synergistically regulate iron homeostasis. Rather than by absorption via membrane transporters, iron is likely gained by degradation of ingested bacteria and efflux via Nramp1 from phagosomes to the cytosol. Nramp gene disruption increases Dictyostelium sensitivity to infection, enhancing intracellular growth of Legionella or Mycobacteria. Generation of mutants in other “iron genes” will help identify genes essential for iron homeostasis and resistance to pathogens.

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The Amoebozoa

Cited by 28 publications

References 76 publications

Terpene synthase genes in eukaryotes beyond plants and fungi: Occurrence in social amoebae

Terpene synthase genes in eukaryotes beyond plants and fungi: Occurrence in social amoebae

ThePhysarum polycephalumGenome Reveals Extensive Use of Prokaryotic Two-Component and Metazoan-Type Tyrosine Kinase Signaling

Iron metabolism and resistance to infection by invasive bacteria in the social amoeba Dictyostelium discoideum

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