skip to main content
US FlagAn official website of the United States government
dot gov icon
Official websites use .gov
A .gov website belongs to an official government organization in the United States.
https lock icon
Secure .gov websites use HTTPS
A lock ( lock ) or https:// means you've safely connected to the .gov website. Share sensitive information only on official, secure websites.

Explore Research Products in the PAR
It may take a few hours for recently added research products to appear in PAR search results.


  • NSF Public Access
  • Search Results
  • Phylogenetic placement of the protosteloid amoeba Microglomus paxillus identifies another case of sporocarpic fruiting in Discosea (Amoebozoa)
Title: Phylogenetic placement of the protosteloid amoeba Microglomus paxillus identifies another case of sporocarpic fruiting in Discosea (Amoebozoa)
Protosteloid amoebae are a paraphyletic assemblage of amoeboid protists found exclusively in the eukaryotic assemblage Amoebozoa. These amoebae can facultatively form a dispersal structure known as a fruiting body, or more specifically, a sporocarp, from a single amoeboid cell. Sporocarps consist of one to a few spores atop a noncellular stalk. Protosteloid amoebae are known in two out of three well-established major assemblages of Amoebozoa. Amoebae with a protosteloid life cycle are known in the major Amoebozoa lineages Discosea and Evosea but not in Tubulinea. To date, only one genus, which is monotypic, lacks sequence data and, therefore, remains phylogenetically homeless. To further clarify the evolutionary milieu of sporocarpic fruiting we used single-cell transcriptomics to obtain data from individual sporocarps of isolates of the protosteloid amoeba Microglomus paxillus. Our phylogenomic analyses using 229 protein coding markers suggest that M. paxillus is a member of the Discosea lineage of Amoebozoa most closely related to Mycamoeba gemmipara. Due to the hypervariable nature of the SSU rRNA sequence we were unable to further resolve the phylogenetic position of M. paxillus in taxon rich datasets using only this marker. Regardless, our results widen the known distribution of sporocarpy in Discosea and stimulate the debate between a single or multiple origins of sporocarpic fruiting in Amoebozoa.  more » « less
Award ID(s):
2100888
PAR ID:
10403326
Author(s) / Creator(s):
; ;
Date Published:
Journal Name:
Journal of Eukaryotic Microbiology
ISSN:
1066-5234
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
More Like this
  1. ; ; ; (, Scientific Reports)
    Abstract The Amoebozoa, a group containing predominantly amoeboid unicellular protists has been shown to play an important ecological role in controlling environmental bacteria. Amoebozoans not only graze bacteria but also serve as a safe niche for bacterial replication and harbor endosymbiotic bacteria including dangerous human pathogens. Despite their importance, only a few lineages of Amoebozoa have been studied in this regard. In this research, we conducted a comprehensive genomic and transcriptomic study with expansive taxon sampling by including representatives from the three known clades of the Amoebozoa. We used culture independent whole culture and single cell genomics/transcriptomics to investigate the association of bacteria with diverse amoebozoans. Relative to current published evidence, we recovered the largest number of bacterial phyla (64) and human pathogen genera (51) associated with the Amoebozoa. Using single cell genomics/transcriptomics we were able to determine up to 24 potential endosymbiotic bacterial phyla, some potentially endosymbionts. This includes the majority of multi-drug resistant pathogens designated as major public health threats. Our study demonstrates amoebozoans are associated with many more phylogenetically diverse bacterial phyla than previously recognized. It also shows that all amoebozoans are capable of harboring far more dangerous human pathogens than presently documented, making them of primal public health concern. 
    more » « less
  2. ; ; ; ; (, Scientific Reports)
    Abstract The supergroup Amoebozoa unites a wide diversity of amoeboid organisms and encompasses enigmatic lineages that have been recalcitrant to modern phylogenetics. Deep divergences, taxonomic placement of some key taxa and character evolution in the group largely remain poorly elucidated or controversial. We surveyed available Amoebozoa genomes and transcriptomes to mine conserved putative single copy genes, which were used to enrich gene sampling and generate the largest supermatrix in the group to date; encompassing 824 genes, including gene sequences not previously analyzed. We recovered a well-resolved and supported tree of Amoebozoa, revealing novel deep level relationships and resolving placement of enigmatic lineages congruent with morphological data. In our analysis the deepest branching group is Tubulinea. A recent proposed major clade Tevosa, uniting Evosea and Tubulinea, is not supported. Based on the new phylogenetic tree, paleoecological and paleontological data as well as data on the biology of presently living amoebozoans, we hypothesize that the evolution of Amoebozoa probably was driven by adaptive responses to a changing environment, where successful survival and predation resulted from a capacity to disrupt and graze on microbial mats-a dominant ecosystem of the mid-Proterozoic period of the Earth history. 
    more » « less
  3. ; ; ; (, Nature Communications)
    Abstract Acrasids are amoebae with the capacity to form multicellular fruiting bodies in a process known as aggregative multicellularity (AGM). This makes acrasids the only known example of multicellularity among the earliest branches of eukaryotes (the former Excavata). Here, we report theAcrasis konagenome sequence plus transcriptomes from pre-, mid- and post-developmental stages. The genome is rich in novelty and genes with strong signatures of horizontal transfer, and multigene families encode nearly half of the amoeba’s predicted proteome. Development inA. konaappears molecularly simple relative to the AGM model,Dictyostelium discoideum. However, the acrasid also differs from the dictyostelid in that it does not appear to be starving during development. Instead, developingA. konaappears to be very metabolically active, does not induce autophagy and does not up-regulate its proteasomal genes. Together, these observations strongly suggest that starvation is not essential for AGM development. Nonetheless, development in the two amoebae appears to employ remarkably similar pathways for signaling, motility and, potentially, construction of an extracellular matrix surrounding the developing cell mass. Much of this similarity is also shared with animal development, suggesting that much of the basic tool kit for multicellular development arose early in eukaryote evolution. 
    more » « less
  4. ; ; ; ; ; (, bioRxiv)
    ABSTRACT PocheinaandAcrasisare two genera of heterolobosean sorocarpic amoebae within Acrasidae that have historically been considered close relatives. The two genera were differentiated based on their differing fruiting body morphologies. The validity of this taxonomic distinction was challenged when a SSU rRNA phylogenetic study placed an isolate morphologically identified as ‘Pocheina’roseawithin a clade ofAcrasis roseaisolates. The authors speculated that pocheinoid fruiting body morphology might be the result of aberrantA. roseafruiting body development, which if true, would nullify this taxonomic distinction between genera. To clarify Acrasidae systematics, we analyzed SSU rRNA and ITS region sequences from multiple isolates ofPocheina, Acrasis, andAllovahlkampfiagenerated by PCR and transcriptomics. We demonstrate that the initial SSU sequence attributed to ‘P. rosea’ originated from anA. roseaDNA contamination in its amplification reaction. Our analyses, based on morphology, SSU and 5.8S rRNA genes phylogenies, as well as comparative analyses of ITS1 and ITS2 sequences, resolve Acrasidae into three major lineages;Allovahlkampfiaand the strongly supported clades comprisingPocheinaandAcrasis. We confirm that the latter two genera can be identified by their fruiting body morphologies. 
    more » « less
  5. ; ; ; ; (, The ISME Journal)
    Abstract The soil amoeba Dictyostelium discoideum acts as both a predator and potential host for diverse bacteria. We tested fifteen Pseudomonas strains that were isolated from transiently infected wild D. discoideum for ability to escape predation and infect D. discoideum fruiting bodies. Three predation-resistant strains frequently caused extracellular infections of fruiting bodies but were not found within spores. Furthermore, infection by one of these species induces secondary infections and suppresses predation of otherwise edible bacteria. Another strain can persist inside of amoebae after being phagocytosed but is rarely taken up. We sequenced isolate genomes and discovered that predation-resistant isolates are not monophyletic. Many Pseudomonas isolates encode secretion systems and toxins known to improve resistance to phagocytosis in other species, as well as diverse secondary metabolite biosynthetic gene clusters that may contribute to predation resistance. However, the distribution of these genes alone cannot explain why some strains are edible and others are not. Each lineage may employ a unique mechanism for resistance. 
    more » « less
  • Citation Formats
  • MLA
  • APA
  • Chicago
  • BibTeX
  • Save / Share this Record
  • Send to Email