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Mycologia 2024A new genus and species of myxomycete, , is described based on numerous observations in Tasmania and additional records from southeastern Australia and New Zealand. The...
A new genus and species of myxomycete, , is described based on numerous observations in Tasmania and additional records from southeastern Australia and New Zealand. The new taxon is characterized by an unusual combination of characters from two families: Lamprodermataceae and Didymiaceae. With Lamprodermataceae the species shares limeless sporocarps, a shining membranous peridium, an epihypothallic stalk, and a cylindrical columella. Like Didymiaceae, it has a soft, flaccid, sparsely branched capillitium, with rough tubular threads that contain fusiform nodes and are firmly connected to the peridium. Other characters of that also occur in many Didymiaceae are the peridium dehiscing into petaloid lobes, the yellow, motile plasmodium, and the spores ornamented with larger, grouped and smaller, scattered warts. The transitional position of the new taxon is reflected by a three-gene phylogeny, which places at the base of the branch of all lime-containing Physarales, thus justifying its description as a monotypic genus.
Topics: Humans; Myxomycetes; Tasmania; Physarida; Spores, Protozoan; Australia; Phylogeny
PubMed: 38032605
DOI: 10.1080/00275514.2023.2274252 -
BMC Microbiology Dec 2022Myxomycetes are a group of eukaryotes belonging to Amoebozoa, which are characterized by a distinctive life cycle, including the plasmodium stage and fruit body stage....
BACKGROUND
Myxomycetes are a group of eukaryotes belonging to Amoebozoa, which are characterized by a distinctive life cycle, including the plasmodium stage and fruit body stage. Plasmodia are all found to be associated with bacteria. However, the information about bacteria diversity and composition in different plasmodia was limited. Therefore, this study aimed to investigate the bacterial diversity of plasmodia from different myxomycetes species and reveal the potential function of plasmodia-associated bacterial communities.
RESULTS
The bacterial communities associated with the plasmodia of six myxomycetes (Didymium iridis, Didymium squamulosum, Diderma hemisphaericum, Lepidoderma tigrinum, Fuligo leviderma, and Physarum melleum) were identified by 16S rRNA amplicon sequencing. The six plasmodia harbored 38 to 52 bacterial operational taxonomic units (OTUs) that belonged to 7 phyla, 16 classes, 23 orders, 40 families, and 53 genera. The dominant phyla were Bacteroidetes, Firmicutes, and Proteobacteria. Most OTUs were shared among the six myxomycetes, while unique bacteria in each species only accounted for a tiny proportion of the total OTUs.
CONCLUSIONS
Although each of the six myxomycetes plasmodia had different bacterial community compositions, a high similarity was observed in the plasmodia-associated bacterial communities' functional composition. The high enrichment for gram-negative (> 90%) and aerobic (> 99%) bacteria in plasmodia suggest that myxomycetes may positively recruit certain kinds of bacteria from the surrounding environment.
Topics: Humans; Myxomycetes; RNA, Ribosomal, 16S; Physarum; Bacteria; Plasmodium
PubMed: 36544088
DOI: 10.1186/s12866-022-02725-5 -
Current Opinion in Genetics &... Aug 2019Single-celled organisms show a fascinating faculty for integrating spatial information and adapting their behaviour accordingly. As such they are of potential interest... (Review)
Review
Single-celled organisms show a fascinating faculty for integrating spatial information and adapting their behaviour accordingly. As such they are of potential interest for elucidating fundamental mechanisms of developmental biology. In this mini-review we highlight current research on two organisms, the true slime mould Physarum polycephalum and the ciliates Paramecium and Tetrahymena. For each of these, we present a case study how applying physical principles to explain behaviour can lead to the understanding of general principles possibly relevant to developmental biology.
Topics: Behavior; Developmental Biology; Paramecium; Physarum polycephalum; Physical Phenomena; Tetrahymena
PubMed: 31449977
DOI: 10.1016/j.gde.2019.06.012 -
Biochemical and Biophysical Research... Nov 2023Desiccation is a severe survival problem for organisms. We have been studying the desiccation tolerance mechanisms in the true slime mold Physarum polycephalum. We...
Desiccation is a severe survival problem for organisms. We have been studying the desiccation tolerance mechanisms in the true slime mold Physarum polycephalum. We measured the trehalose content of P. polycephalum vegetative cells (plasmodia) and drought cells (sclerotia). Surprisingly, we found that the content in sclerotia was about 473-fold greater than in the plasmodia. We then examined trehalose metabolism-related genes via RNAseq, and consequently found that trehalose 6-phosphate phosphorylase (T6pp) expression levels increased following desiccation. Next, we cloned and expressed the genes for T6pp, trehalose 6-phosphate synthase/phosphatase (Tps/Tpp), maltooligosyltrehalose trehalohydrolase (TreZ), and maltooligosyltrehalose synthase (TreY) in E. coli. Incidentally, TreY and TreZ clones have been reported in several prokaryotes, but not in eukaryotes. This report in P. polycephalum is the first evidence of their presence in a eukaryote species. Recombinant T6pp, TreY, and TreZ were purified and confirmed to be active. Our results showed that these enzymes catalyze reactions related to trehalose production, and their reaction kinetics follow the Michaelis-Menten equation. The t6pp mRNA levels of the sclerotia were about 15-fold higher than in the plasmodia. In contrast, the expression levels of TreZ and TreY showed no significant change between the sclerotia and plasmodia. Thus, T6pp is probably related to desiccation tolerance, whereas the contribution of TreY and TreZ is insufficient to account for the considerable accumulation of trehalose in sclerotia.
Topics: Trehalose; Escherichia coli; Physarum; Biosynthetic Pathways; Phosphates
PubMed: 37832387
DOI: 10.1016/j.bbrc.2023.09.090 -
Philosophical Transactions of the Royal... Apr 2023Changes in behaviour over the lifetime of single-cell organisms have primarily been investigated in response to environmental stressors. However, growing evidence...
Changes in behaviour over the lifetime of single-cell organisms have primarily been investigated in response to environmental stressors. However, growing evidence suggests that unicellular organisms undergo behavioural changes throughout their lifetime independently of the external environment. Here we studied how behavioural performances across different tasks vary with age in the acellular slime mould . We tested slime moulds aged from 1 week to 100 weeks. First, we showed that migration speed decreases with age in favourable and adverse environments. Second, we showed that decision making and learning abilities do not deteriorate with age. Third, we revealed that old slime moulds can recover temporarily their behavioural performances if they go throughout a dormant stage or if they fuse with a young congener. Last, we observed the response of slime mould facing a choice between cues released by clone mates of different age. We found that both old and young slime moulds are attracted preferentially toward cues left by young slime moulds. Although many studies have studied behaviour in unicellular organisms, few have taken the step of looking for changes in behaviour over the lifetime of individuals. This study extends our knowledge of the behavioural plasticity of single-celled organisms and establishes slime moulds as a promising model to investigate the effect of ageing on behaviour at the cellular level. This article is part of a discussion meeting issue 'Collective behaviour through time'.
Topics: Humans; Infant, Newborn; Physarum polycephalum; Learning; Cues
PubMed: 36802777
DOI: 10.1098/rstb.2022.0063 -
AMB Express Jun 2021Given the emerging multidrug-resistant pathogens, the number of effective antimicrobial agents to deal with the threat of bacterial and fungal resistance has fallen... (Review)
Review
Given the emerging multidrug-resistant pathogens, the number of effective antimicrobial agents to deal with the threat of bacterial and fungal resistance has fallen dramatically. Therefore, the critical solution to deal with the missing effective antibiotics is to research new sources or new synthetic antibiotics. Natural products have different advantages to be considered antimicrobial agents. There are different natural sources for antimicrobial agents, such as bacteria, fungi, algae, slime molds, and plants. This article has focused on antibiotics from slime molds, especially Myxomycetes. The reason why slime molds have been chosen to be studied is their unique bioactive metabolites, especially over the past couple of decades. Some of those metabolites have been demonstrated to possess antibiotic activities. Hence, this article has focused on the potential of these creatures as an alternative source of antibiotics.
PubMed: 34160704
DOI: 10.1186/s13568-021-01251-3 -
BMC Biotechnology Mar 2021Microbial polysaccharides have been reported to possess remarkable bioactivities. Physarum polycephalum is a species of slime mold for which the microplasmodia are...
BACKGROUND
Microbial polysaccharides have been reported to possess remarkable bioactivities. Physarum polycephalum is a species of slime mold for which the microplasmodia are capable of rapid growth and can produce a significant amount of cell wall-less biomass. There has been a limited understanding of the polysaccharides produced by microplasmodia of slime molds, including P. polycephalum. Thus, the primary objectives of this research were first to chemically characterize the exopolysaccharides (EPS) and intracellular polysaccharides (IPS) of P. polycephalum microplasmodia and then to evaluate their cytotoxicity against several cancer cell lines.
RESULTS
The yields of the crude EPS (4.43 ± 0.44 g/l) and partially purified (deproteinated) EPS (2.95 ± 0.85 g/l) were comparable (p > 0.05) with the respective crude IPS (3.46 ± 0.36 g/l) and partially purified IPS (2.45 ± 0.36 g/l). The average molecular weight of the EPS and IPS were 14,762 kDa and 1788 kDa. The major monomer of the EPS was galactose (80.22%), while that of the IPS was glucose (84.46%). Both crude and purified IPS samples showed significantly higher cytotoxicity toward Hela cells, especially the purified sample and none of the IPSs inhibited normal cells. Only 38.42 ± 2.84% Hela cells remained viable when treated with the partially purified IPS (1 mg/ml). However, although only 34.76 ± 6.58% MCF-7 cells were viable when exposed to the crude IPS, but the partially purified IPS displayed non-toxicity to MCF-7 cells. This suggested that the cytotoxicity toward MCF-7 would come from some component associated with the crude IPS sample (e.g. proteins, peptides or ion metals) and the purification process would have either completely removed or reduced amount of that component. Cell cycle analysis by flow cytometry suggested that the mechanism of the toxicity of the crude IPS toward MCF-7 and the partially purified IPS toward Hela cells was due to apoptosis.
CONCLUSIONS
The EPS and IPS of P. polycephalum microplasmodia had different chemical properties including carbohydrate, protein and total sulfate group contents, monosaccharide composition and molecular weights, which led to different cytotoxicity activities. The crude and partially purified IPSs would be potential materials for further study relating to cancer treatment.
Topics: Antineoplastic Agents; HeLa Cells; Humans; MCF-7 Cells; Molecular Weight; Physarum polycephalum; Polysaccharides
PubMed: 33773573
DOI: 10.1186/s12896-021-00688-5 -
ELife Feb 2022In multicellular organisms, the specification, coordination, and compartmentalization of cell types enable the formation of complex body plans. However, some eukaryotic...
In multicellular organisms, the specification, coordination, and compartmentalization of cell types enable the formation of complex body plans. However, some eukaryotic protists such as slime molds generate diverse and complex structures while remaining in a multinucleate syncytial state. It is unknown if different regions of these giant syncytial cells have distinct transcriptional responses to environmental encounters and if nuclei within the cell diversify into heterogeneous states. Here, we performed spatial transcriptome analysis of the slime mold in the plasmodium state under different environmental conditions and used single-nucleus RNA-sequencing to dissect gene expression heterogeneity among nuclei. Our data identifies transcriptome regionality in the organism that associates with proliferation, syncytial substructures, and localized environmental conditions. Further, we find that nuclei are heterogenous in their transcriptional profile and may process local signals within the plasmodium to coordinate cell growth, metabolism, and reproduction. To understand how nuclei variation within the syncytium compares to heterogeneity in single-nucleus cells, we analyzed states in single amoebal cells. We observed amoebal cell states at different stages of mitosis and meiosis, and identified cytokinetic features that are specific to nuclei divisions within the syncytium. Notably, we do not find evidence for predefined transcriptomic states in the amoebae that are observed in the syncytium. Our data shows that a single-celled slime mold can control its gene expression in a region-specific manner while lacking cellular compartmentalization and suggests that nuclei are mobile processors facilitating local specialized functions. More broadly, slime molds offer the extraordinary opportunity to explore how organisms can evolve regulatory mechanisms to divide labor, specialize, balance competition with cooperation, and perform other foundational principles that govern the logic of life.
Topics: Gene Expression Regulation; Giant Cells; Physarum polycephalum; RNA-Seq; Single-Cell Analysis; Transcriptome
PubMed: 35195068
DOI: 10.7554/eLife.69745 -
Journal of Basic Microbiology Jun 2023Myxogastrea is a group of eukaryotic microorganisms included in Amoebozoa. Its life cycle includes two trophic stages: plasmodia and myxamoeflagellates. However, only...
Myxogastrea is a group of eukaryotic microorganisms included in Amoebozoa. Its life cycle includes two trophic stages: plasmodia and myxamoeflagellates. However, only about 102 species have their complete life cycle known in literature and only about 18 species have their plasmodial axenic culture accomplished in laboratory conditions. The research presented herein involved culturing of Physarum galbeum on the water agar medium. The events that transpired during its life cycle including spore germination, plasmodia formation, and sporocarp development were documented especially the subglobose or discoid sporotheca and the stalk formation. The spores germinated by the V-shape split method to release a single protoplasm. Yellow-green pigmented phaneroplasmodia developed into sporocarps by subhypothallic type. The present article gives details of the sporocarp development of P. galbeum and its plasmodial axenic culture on solid and liquid mediums.
Topics: Animals; Physarum; Axenic Culture; Culture Media; Life Cycle Stages
PubMed: 36976270
DOI: 10.1002/jobm.202200256 -
Mycologia 2021Five specimens, initially presumed to be or , were collected from Jilin Province and the Inner Mongolia Autonomous Region in China, but all five turned out to represent...
Five specimens, initially presumed to be or , were collected from Jilin Province and the Inner Mongolia Autonomous Region in China, but all five turned out to represent a new aethaloid species, . This new species is characterized by pseudocapillitia without capillitia and an aethalioid fruiting body, features that are morphologically distinct from those of any other species of . To assess the phylogenetic relationships between and other members of and in the Didymiaceae, sequences from two nonoverlapping targeted portions of nuc 18S rDNA (~450 bp and ~1050 bp) and translation elongation factor 1-alpha () were obtained and analyzed. The results indicate that forms a single clade separate from other species of and the clade that contains , which strongly supports the identification of the five specimens as a new species.
Topics: Ascomycota; China; DNA, Ribosomal; Phylogeny; Physarida
PubMed: 34236946
DOI: 10.1080/00275514.2021.1922224