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Scanning electron micrographs of capillitium and spores of Physarum parvicalcareum . A- Capillitium with calcareous deposits (arrows). B- Single spore. C- Spores with capillitium that is free of deposits. D- Isolated portion of smooth capillitium with grain (calcareous deposit).
Source publication
A new species of plasmodial slime mold, Physarum parvicalcareum, recorded from flowering stalks, leaves and stems of the common heather (Calluna vulgaris) that commonly inhabits boreal pine forests in Thuringia (Germany) is described on the basis of morphological features of the capillitium and the spores. Phylogenetic trees, reconstructed using da...
Context in source publication
Context 1
... violet to bronze, some individuals conspicuously iridescent, colourless in transmitted light, dehiscence irregular. Columella or pseudo-columella absent. Capillitium consists of a three-dimensional net with small meshes, white to pale-yellow, colourless in transmitted light, filamentous, with few swellings, covered with small lime granules ( Fig. 2A-D), sometimes with a band-like widened appearance, (1-)2-5(-7) µm in diameter. Spores dark-brown, grey- brown or dark-brown in transmitted light, globose, 10-11(-12) µm in diam., densely covered with dark, coarse, more or less irregular warts. Plasmodium not ...
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Citations
... Germany). The spores were isolated from the fruiting bodies under sterile conditions and prepared for scanning electron microscopy (SEM) as described by Hoppe and Kutschera (2010). SEM images of spores from 320 species of myxomycetes were obtained and analyzed by visual inspection of the images. ...
... The life cycle of the myxomycetes was reconstructed based on observations of two representative species (Fuligo septica (L.) F. H. Wigg. 1780; Didymium nigripes (Link) Fr. 1818) that were maintained on petri dishes under laboratory conditions, as described by Hoppe and Kutschera (2010). ...
Detailed analyses into the life cycle of the soil-dwelling microbe Dictyostelium discoideum led to the conclusion that this “social amoeba” practices some form of “non-monoculture farming” via the transfer of bacteria to novel environments. Herein, we show that in myxomycetes (plasmodial slime molds or myxogastrids) a similar “farming symbiosis” has evolved. Based on laboratory studies of two representative species in the genera Fuligo and Didymium, the sexual life cycle of these enigmatic microbes that feed on bacteria was reconstructed, with reference to plasmo- and karyogamy. We document that the spores carry and transfer bacteria and hence may inoculate new habitats. The significance of this finding with respect to Ernst Haeckel’s work on myxomycetes and his concept of ecology are addressed.
... Only in recent years first phylogenies of the group were constructed (Fiore-Donno et al. 2012). The prevailing species concept is still based on the morphological characters of the fructifications, and only a few of the latest papers (e.g., Hoppe et al. 2010; Leontyev et al. 2014; Novozhilov et al. 2013a, b) on myxomycete taxonomy employ molecular markers, especially partial sequences for the nuclear small subunit ribosomal RNA gene (SSU). This gene is widely accepted as a barcode marker for other groups of protists (Pawlowski et al. 2012; Adl et al. 2014). ...
Specimens of the snowbank myxomycete Meriderma atrosporum agg. from five European mountain ranges were sequenced for parts of the nuclear small subunit ribosomal RNA gene (SSU) and the protein elongation factor 1 alpha gene (EF1A). A phylogeny of the EF1A gene, including a very variable spliceosomal intron, resulted in seven phylogroups, and this topology was confirmed by SSU sequences. Two thirds of all specimens were heterozygous for the EF1A gene, and the two haplotypes of these specimens occurred always in the same phylogroup. Except for two cases in closely related phylogroups all ribotypes were as well limited to one phylogroup. This pattern is consistent with the assumption of reproductively isolated sexual biospecies. Numbers of EF1A-haplotypes shared between mountain ranges correlate with geographical distance, suggesting relative isolation but occasional long-distance dispersal by spores. Most subpopulations (divided by putative biospecies and mountain ranges) were in Hardy-Weinberg equilibrium. A simulation assuming panmixis within but not in between subpopulations suggested that similar numbers of shared genotypes can be created by chance through sexual reproduction alone. Our results support the biospecies concept, derived from experiments with cultivable members of the Physarales. We discuss the results on the background of possible reproductive options in myxomycetes.
... Accordingly, he described the properties of the "protoplasm of the plant cell" with reference to the plasmodium of myxomycetes, such as Physarum polycephalum and other well-studied species. [3][4][5] In his Experimental-Physiologie der Pflanzen (Experimental Physiology of Plants), Sachs (1865), 6 adopted de Bary's and Hofmeister's view, and described intracellular processes related to the properties of the protoplasm with reference to the myxomycetes. ...
... Swarm cells (myxamoebae) were obtained and cultivated on agar plates (Reasoner's 2A agar) as described by Hoppe and Kutschera. 3,4 The swarming behavior of samples of myxamoebae (50 -200 cells per experiment) was analyzed using an Inverse-light microscope (ID 03, Zeiss Germany) via series of photographs taken on the same samples from days zero to 10 after start of the swarming experiment (25 C, darkness) ...
On decaying wood or litter in forests, plasmodial slime molds (myxomycetes) represent a large fraction of eukaryotic protists that feed on bacteria. In his seminal book Experimental Physiology of Plants (1865), Julius Sachs referred to the multinucleate plasmodium of myxomycetes, which were considered at that time as primitive plants (or fungi). Today it is well established that myxomycetes are members of the Amoebozoa (Protista). In this study we compare the mobility of myxamoebae of three European species, Lycogala epidendrum (order Liceales), Tubulifera arachnoidea, and Trichia decipiens (order Trichiales). Using agar plates, on which three separate bacterial species were cultivated as prey organisms (Methylobacterium mesophilicum, Escherichia coli, Agrobacterium tumefaciens), we document large differences in cell motility between the myxomycetes investigated. In addition, we show that the three species of myxamoebae can be distinguished based on their average cell size. These data shed light on the mode of co-occurrence via differential substrate utilization in these members of the Amoebozoa.
The moist chamber technique was used to obtain Cribraria lepida , Physarum dictyosporum , and P . diderma from wood or bark at different outdoor localities in Karaman Province and P . spectabile in Konya Province. These taxa are reported for the first time from Turkey.
Herbarium collections provide an essential basis for a wide array of biological research and, with development of DNA-based methods, they have become an invaluable material for genetic analyses. Yet, the use of such material is hindered by technical limitations related to DNA degradation and to quantity of biological material. The latter is inherent for some biological groups, as best exemplified by myxomycetes which form minute sporophores. It is estimated that ca. two-thirds of myxomycete taxa are represented by extremely scanty material. As DNA isolation methods applied so far in myxomycete studies require destructive sampling of many sporophores, a large part of described diversity of the group remains unavailable for phylogenetic studies or barcoding. Here, we tested several procedures of DNA isolation and amplification to seek for an efficient and possibly non-destructive method of sampling. Tests were based on herbarium specimens of 19 species representing different taxonomic orders. We assayed several variants of isolation based on silica gel membrane columns, and a newly designed procedure using highly reduced amount of biological material (small portion of spores), based on fine disruption of spores and direct PCR. While the most frequently used column-based method led to PCR success in 89.5% of samples when a large amount of material was used, its performance dropped to 52% when based on single sporophores. Single sporophores provided amplicons in 89.5% of samples when using a kit dedicated to low-amount DNA samples. Our new procedure appeared the most effective (94.7%) while it used only a small fraction of spores, being nearly non-destructive; it was also the most cost-effective. We thus demonstrate that combination of adequate handling of spore micro-disruption coupled with application of direct PCR can be an efficient way to circumvent technical limitations for genetic studies in myxomycetes and thus can substantially improve taxon sampling for phylogeny and barcoding. Additionally, this approach gives a unique possibility to apply both molecular and morphological assays to the same structure (sporophore), which then can be further stored as documentation.
In recent decades, employing molecular genetic research methods to study myxomycetes has become increasingly important. The use of molecular approaches to the study of myxomycetes has occurred rather late compared to their use in other groups of organisms. Nevertheless, molecular studies are revealing information that was never before possible to obtain, allowing a better understanding of these unique and understudied amoeboid protists. This chapter is organized into two parts. In Part A, the molecular methods that have been applied in investigations of myxomycetes will be described, followed by a discussion of the ways in which these techniques have been used to enhance our understanding of myxomycete biodiversity and ecology. In Part B, molecular approaches to understanding the basic biology of myxomycetes will be reviewed.
Myxomycetes are also called plasmodial slime molds, due to one of their characteristic features, the occurrence of the plasmodium. However, most of the distinguishing characters of the five orders currently recognised are based on the morphology of fruiting bodies and spores. Although a few myxomycetes have become widely used model organisms for genetic and cytological studies, complete information relating to the number of chromosomes in haploid cells (n) is lacking thus far. Only two species of the order Physarales have been examined with respect to chromosome numbers. Here, we present a complete data set on the numbers of chromosomes in ten species of myxomycetes that are members of all five orders. Our analysis indicates that n =21 is the evolutionary ancient chromosome number that occurs in the morphologically simple orders Liceales and Ceratiomyxales. More derived taxa, such as the Physarales, have significantly higher chromosome numbers (n =30). These data shed light on the phylogenetic relationships within the myxomycetes.
