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Sporulation of Stemonitis fusca. A-E. Period of sporotheca formation. E, F, G. Period of stalk formation. G, H-L. Period of sporocarp maturity. Scale bars: A = 5 mm; B-L = 2 mm.
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Myxogastria is a group of protozoa characterized by cellular uninucleate amoeboflagellates (myxamoebae and flagellated swarm cell), acellular multinucleate plasmodia and stationary spore‐bearing sporocarps. The Stemonitales is a large order in the Myxogastria and contains approximately 230 species, but only 13 species have their completed life cycl...
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... began with the appearance of milk-white coralloid plasmodia after exposure to natural sunlight (12 h of light and 12 h of darkness for three photoperiods in sunny weather). The sporulation of S. fusca can be divided into three periods: (i) Sporotheca formation (Fig. 5A-F). During this period, the coralloid plasmodium formed an anomalous mass and then separated into several primordia (Fig. 5A, B). The hypothallus was laid first underneath the primordium by protoplasmic secretion before primordial elongation. Gradually, the individual primordia elongated as the columella formed inside (the young ...
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... coralloid plasmodia after exposure to natural sunlight (12 h of light and 12 h of darkness for three photoperiods in sunny weather). The sporulation of S. fusca can be divided into three periods: (i) Sporotheca formation (Fig. 5A-F). During this period, the coralloid plasmodium formed an anomalous mass and then separated into several primordia (Fig. 5A, B). The hypothallus was laid first underneath the primordium by protoplasmic secretion before primordial elongation. Gradually, the individual primordia elongated as the columella formed inside (the young sporotheca), and finally assumed the cylindrical shape of a mature sporotheca ( Fig. 5C-F). This process lasted for 133 min. (ii) Stalk ...
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... mass and then separated into several primordia (Fig. 5A, B). The hypothallus was laid first underneath the primordium by protoplasmic secretion before primordial elongation. Gradually, the individual primordia elongated as the columella formed inside (the young sporotheca), and finally assumed the cylindrical shape of a mature sporotheca ( Fig. 5C-F). This process lasted for 133 min. (ii) Stalk formation (Fig. 5F, G). When the sporotheca had attained full height (5.5-7.2 mm), the stalk, already formed as columella inside the sporotheca started to show as the sporotheca moved upwards. The sporotheca remained white until the full stalk height was reached (1.7-2.5 mm). This period ...
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... The hypothallus was laid first underneath the primordium by protoplasmic secretion before primordial elongation. Gradually, the individual primordia elongated as the columella formed inside (the young sporotheca), and finally assumed the cylindrical shape of a mature sporotheca ( Fig. 5C-F). This process lasted for 133 min. (ii) Stalk formation (Fig. 5F, G). When the sporotheca had attained full height (5.5-7.2 mm), the stalk, already formed as columella inside the sporotheca started to show as the sporotheca moved upwards. The sporotheca remained white until the full stalk height was reached (1.7-2.5 mm). This period took 36 min (at approximately 23 °C). (iii) Sporocarp maturity (Fig. ...
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... (Fig. 5F, G). When the sporotheca had attained full height (5.5-7.2 mm), the stalk, already formed as columella inside the sporotheca started to show as the sporotheca moved upwards. The sporotheca remained white until the full stalk height was reached (1.7-2.5 mm). This period took 36 min (at approximately 23 °C). (iii) Sporocarp maturity (Fig. 5H-L). In the following 150 min, when the stalk had attained full height, the color of the sporotheca changed from white to pinkish, to pink, to reddish-brown, and finally became dark as the spores developed. The entire sporulation process took about 11 h to complete. The shiny immature peridium that is present in the early stages of ...
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... began with the appearance of milk-white coralloid plasmodia after exposure to natural sunlight (12 h of light and 12 h of darkness for three photoperiods in sunny weather). The sporulation of S. fusca can be divided into three periods: (i) Sporotheca formation (Fig. 5A-F). During this period, the coralloid plasmodium formed an anomalous mass and then separated into several primordia (Fig. 5A, B). The hypothallus was laid first underneath the primordium by protoplasmic secretion before primordial elongation. Gradually, the individual primordia elongated as the columella formed inside (the young ...
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... coralloid plasmodia after exposure to natural sunlight (12 h of light and 12 h of darkness for three photoperiods in sunny weather). The sporulation of S. fusca can be divided into three periods: (i) Sporotheca formation (Fig. 5A-F). During this period, the coralloid plasmodium formed an anomalous mass and then separated into several primordia (Fig. 5A, B). The hypothallus was laid first underneath the primordium by protoplasmic secretion before primordial elongation. Gradually, the individual primordia elongated as the columella formed inside (the young sporotheca), and finally assumed the cylindrical shape of a mature sporotheca ( Fig. 5C-F). This process lasted for 133 min. (ii) Stalk ...
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... mass and then separated into several primordia (Fig. 5A, B). The hypothallus was laid first underneath the primordium by protoplasmic secretion before primordial elongation. Gradually, the individual primordia elongated as the columella formed inside (the young sporotheca), and finally assumed the cylindrical shape of a mature sporotheca ( Fig. 5C-F). This process lasted for 133 min. (ii) Stalk formation (Fig. 5F, G). When the sporotheca had attained full height (5.5-7.2 mm), the stalk, already formed as columella inside the sporotheca started to show as the sporotheca moved upwards. The sporotheca remained white until the full stalk height was reached (1.7-2.5 mm). This period ...
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... The hypothallus was laid first underneath the primordium by protoplasmic secretion before primordial elongation. Gradually, the individual primordia elongated as the columella formed inside (the young sporotheca), and finally assumed the cylindrical shape of a mature sporotheca ( Fig. 5C-F). This process lasted for 133 min. (ii) Stalk formation (Fig. 5F, G). When the sporotheca had attained full height (5.5-7.2 mm), the stalk, already formed as columella inside the sporotheca started to show as the sporotheca moved upwards. The sporotheca remained white until the full stalk height was reached (1.7-2.5 mm). This period took 36 min (at approximately 23 °C). (iii) Sporocarp maturity (Fig. ...
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... (Fig. 5F, G). When the sporotheca had attained full height (5.5-7.2 mm), the stalk, already formed as columella inside the sporotheca started to show as the sporotheca moved upwards. The sporotheca remained white until the full stalk height was reached (1.7-2.5 mm). This period took 36 min (at approximately 23 °C). (iii) Sporocarp maturity (Fig. 5H-L). In the following 150 min, when the stalk had attained full height, the color of the sporotheca changed from white to pinkish, to pink, to reddish-brown, and finally became dark as the spores developed. The entire sporulation process took about 11 h to complete. The shiny immature peridium that is present in the early stages of ...
Citations
... The sporocarp of P. galbeum developed as the primordia elongated with the bulk of cytoplasm migrating to the immature sporotheca, and stalk surrounding membrane constricted to form the membranous stalk, which is a typical subhypothallic sporocarp development. Stalked species of physarales produce globose or subglobose, rarely cylindrical sporotheca owing to the loss of columella or the existence of short columella or pseudocolumella [14,16,17,28,[32][33][34], whereas stalked species of Stemonitales display globose or cylindrical sporotheca which was formed along its internally secreted columella [8,[36][37][38][39]. ...
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.
... The latter had one or two flagella from one pole of the cell, which were roughly 7 μm in diameter. Similar to Stemonitis fusca, we observed transparent, rounded, and irregular shaped flagellated protoplasts 7.5-10 μm in length (Dai et al., 2020). The 18S rRNA gene sequence had a best hit (e-value = 2E-120) corresponding to a member of the Amoebozoa supergroup, Stemonitis sp., with 99.79% identity (see phylogeny in Frontiers in Microbiology | www.frontiersin.org ...
... are slime molds with unique characteristics, such as a spore-to-spore life cycle, and commonly found on decaying plant matter in terrestrial ecosystems (Stephenson and Stempen, 1994). Depending on growth conditions, they can be found as cellular uninucleate amoeboflagellates, acellular multinucleate plasmodia, and stationary spore-bearing sporocarps (Dai et al., 2020). While we only observed unicellular and flagellated states, the composition of our media could explain the absence of plasmodia and sporocarps, as the formation Frontiers in Microbiology | www.frontiersin.org of plasmodia and sporulation commonly occur on water-or oat-agar surfaces (Dai et al., 2020). ...
... Depending on growth conditions, they can be found as cellular uninucleate amoeboflagellates, acellular multinucleate plasmodia, and stationary spore-bearing sporocarps (Dai et al., 2020). While we only observed unicellular and flagellated states, the composition of our media could explain the absence of plasmodia and sporocarps, as the formation Frontiers in Microbiology | www.frontiersin.org of plasmodia and sporulation commonly occur on water-or oat-agar surfaces (Dai et al., 2020). Temperature, pH, numbers of cells, and the duration of photoperiods are also important variables that affect how plasmodial slime molds complete their life cycles (Gao et al., 2017;Zhu et al., 2019;Dai et al., 2020). ...
Protozoa play important roles in microbial communities, regulating populations via predation and contributing to nutrient cycling. While amoebae have been identified in acid rock drainage (ARD) systems, our understanding of their symbioses in these extreme environments is limited. Here, we report the first isolation of the amoeba Stemonitis from an ARD environment as well as the genome sequence and annotation of an associated bacterium, Dyella terrae strain Ely Copper Mine, from Ely Brook at the Ely Copper Mine Superfund site in Vershire, Vermont, United States. Fluorescent in situ hybridization analysis showed this bacterium colonizing cells of Stemonitis sp. in addition to being outside of amoebal cells. This amoeba-resistant bacterium is Gram-negative with a genome size of 5.36 Mbp and GC content of 62.5%. The genome of the D. terrae strain Ely Copper Mine encodes de novo biosynthetic pathways for amino acids, carbohydrates, nucleic acids, and lipids. Genes involved in nitrate (1) and sulfate (7) reduction, metal (229) and antibiotic resistance (37), and secondary metabolite production (6) were identified. Notably, 26 hydrolases were identified by RAST as well as other biomass degradation genes, suggesting roles in carbon and energy cycling within the microbial community. The genome also contains type IV secretion system genes involved in amoebae resistance, revealing how this bacterium likely survives predation from Stemonitis sp. This genome analysis and the association of D. terrae strain Ely Copper Mine with Stemonitis sp. provide insight into the functional roles of amoebae and bacteria within ARD environments.
... In the present study no intermediate phases between the initial sporocarps and the fully formed ones were detected. Intermediate phases are described in detail elsewhere (Dai et al., 2020;Indira, 1971). Yet, coralloid plasmodium was detected at different stages up to decay (dessication) possibly due to stress caused by the environmental factors (Figure 2). ...
... Our specimen presented warted spores, therefore preliminary analysis indicates it as a member of this genus. Also, several species were discarded according to ornamentation and size of spores: S. lignicola (Poulain et al., 2011), S. fusca and S. typhina (Dai et al., 2020), S. herbatica (Indira, 1969), S. planusis (Bo & Yu, 2017). Ground litter (consisting mostly of dead leaves) on the forest floor is one of the primary substrates for myxomycetes (Martin & Alexopoulos, 1969;Stephenson & Stempen, 1994). ...
Myxomycetes are naturally occurring organisms with habitats from tropical to temperate area with preference for humid and diverse ecosystems. Yet, an association of myxomycetes-sweet potato in Romania, on sandy soils has been detected in 2020. Sweet potatoes are cultivated at Dabuleni Research Station in mixture of forest top soil, sand and peat under greenhouse conditions. Relative humidity and temperatures are high throughout the season with highest values at the end of summer, favouring myxomycetes organism to complete its life cycle. Several stages of plasmodium and sporangia were observed in the field. The crop was not affected by the colonization of myxomycetes. Morphological identification lead to a species of Stemonitidales. This is the first report in Romania of myxomycetes-crop association.
Despite various attempts during the last few decades to establish a natural system for the Myxomycetes, researchers have not yet reached a consensus. One of the most drastic recent proposals is the movement of the genus Lamproderma, an almost a trans-subclass transfer. The traditional subclasses are not supported by current molecular phylogenies, and various higher classifications have been proposed during the last decade. However, the taxonomic characteristics on which the traditional higher classifications were based have not been reinvestigated. In the present study, the key species involved in this transfer, Lamproderma columbinum (the type species of the genus Lamproderma), was assessed using correlational morphological analysis of stereo, light, and electron microscopic images. Correlational analysis of the plasmodium, fruiting body formation, and the mature fruiting bodies revealed that several concepts of taxonomic characteristics that have been used to distinguish higher classifications are questionable. The results of this study indicate that caution is required when interpreting the evolution of morphological traits in Myxomycetes, as the current concepts are vague. The definitions of the taxonomic characteristics need a detailed research, and attention should be paid to the lifecycle timing of observations, before discussing a natural system for Myxomycetes.
Myxomycetes, one of the lowest classes of eukaryote (true slime molds), are an unusual group of primitive organisms. Their life cycle consists of two stages, namely the free-living plasmodium and the fruiting body with unique structures and colors. The chemical studies on the secondary metabolites of the myxomycetes are limited due to a lack of understanding of their laboratory cultivation. In this review, 93 natural products from myxomycetes, including their chemical structures and bioactivities were described. We also provided a conceptual overview over five culture methods of myxomycetes, including moist chamber culture, feeding culture, pure culture, liquid culture and hanging drop culture.
