Protosteliales | |
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Ceratiomyxa sp. | |
Scientific classification | |
Domain: | |
(unranked): | |
Infraphylum: | |
Class: | Protostelea |
Order: | Protosteliida Shadwick & Spiegel in Adl et al. 2012 |
Families and genera | |
Protosteliomycetes/Protosteliales (ICBN) or Protostelea/Protostelia/Protosteliida [1] (ICZN) is a grouping of slime molds from the phylum Mycetozoa. [2] [3] The name can vary depending upon the taxon used. Other names include Protostelea, [4] Protostelia, [5] and Protostelida. [6] When not implying a specific level of classification, the term protostelid or protosteloid amoeba is sometimes used. [7]
Protosteloid amoebae, also called protostelids, are amoebae that are capable of making simple fruiting bodies consisting of a cellular stalk topped by one or a few spores. [8] All species are microscopic and are typically found on dead plant matter where they consume bacteria, yeasts, and fungal spores. Since protostelids are amoebae that make spores, they are considered to be slime molds. [9]
It includes for example the following genera:
As a subclass, Protostelia has been described as paraphyletic to the protostelid clade, as Protostelia excludes the clade of myxomycetes, which are embedded in the protostelid clade. [10]
The formal taxonomy of protosteloid amoebae groups them all according to fruiting bodies, mostly leaving out characteristics of the amoebae. Recent studies have shown that all protosteloid amoebae studied to date are probably included in the group known as Amoebozoa or Eumycetozoa. [11] [12] However, protosteloid amoebae are not all closely related and some fall within groups of amoebae in which the other amoebae are nonfruiting. [11] [12] Therefore, it appears that the ability to make fruiting bodies may have evolved more than once.
Protosteloid amoebae are typically found on dead plant matter, including stems and leaves of herbaceous plants, stems and leaves of grasses, bark of living trees, decaying wood and other types of dead plant matter. [8] Some species are aquatic; they live on dead plant parts submerged in a pond. [13] [14] Others live on the petals of living flowers and on living tree leaves. Since protosteloid amoebae eat bacteria, yeasts, and fungal spores in the laboratory, it is thought that they also do this in nature. [9] They are thus thought to be predators in the decomposer community. [9]
Collections of protostelids have been made from all continents, including the Antarctic peninsula. Protostelids have also been found on isolated islands like Hawaii in the Pacific and Ascension Island in the southern Atlantic, [15] [16] indicating that protostelids have a worldwide distribution. Most studies of protostelid distribution have been done in the temperate zones so they are best known from these areas. [17] [18] However, tropical studies have turned up protostelids, often in great abundance. [19]
Since protosteloid amoebae are microscopic one must bring their substrates, dead plant matter, into the laboratory to find them. Dead plant matter is placed on the agar surface in a petri plate and allowed to incubate for several days to a week. Then the edges of the substrates are scanned with a compound microscope and species are identified by their fruiting body morphology and amoebal morphology. [9]
When protosteloid fruiting bodies are found they can be moved into laboratory culture onto an appropriate food organism or mix of organisms. This is done by picking up fruiting bodies or spores with a sterilised needle and moving them onto agar in a fresh petri plate that has been smeared with a bacterium or yeast upon which the protosteloid amoeba species has been known to grow. If the spores germinate then the protostelid begins eating the food organism and a culture is established. [9]
Slime mold or slime mould is an informal name given to a polyphyletic assemblage of unrelated eukaryotic organisms in the Stramenopiles, Rhizaria, Discoba, Amoebozoa and Holomycota. Most are microscopic; those in the Myxogastria form larger plasmodial slime molds visible to the naked eye. The slime mold life cycle includes a free-living single-celled stage and the formation of spores. Spores are often produced in macroscopic multicellular or multinucleate fruiting bodies that may be formed through aggregation or fusion; aggregation is driven by chemical signals called acrasins. Slime molds contribute to the decomposition of dead vegetation; some are parasitic.
The dictyostelids or cellular slime molds are a group of slime molds or social amoebae.
Mycetozoa is a polyphyletic grouping of slime molds. It was originally thought to be a monophyletic clade, but recently it was discovered that protostelia are a polyphyletic group within Conosa.
Dictyostelium is a genus of single- and multi-celled eukaryotic, phagotrophic bacterivores. Though they are Protista and in no way fungal, they traditionally are known as "slime molds". They are present in most terrestrial ecosystems as a normal and often abundant component of the soil microflora, and play an important role in the maintenance of balanced bacterial populations in soils.
Amoebozoa is a major taxonomic group containing about 2,400 described species of amoeboid protists, often possessing blunt, fingerlike, lobose pseudopods and tubular mitochondrial cristae. In traditional classification schemes, Amoebozoa is usually ranked as a phylum within either the kingdom Protista or the kingdom Protozoa. In the classification favored by the International Society of Protistologists, it is retained as an unranked "supergroup" within Eukaryota. Molecular genetic analysis supports Amoebozoa as a monophyletic clade. Modern studies of eukaryotic phylogenetic trees identify it as the sister group to Opisthokonta, another major clade which contains both fungi and animals as well as several other clades comprising some 300 species of unicellular eukaryotes. Amoebozoa and Opisthokonta are sometimes grouped together in a high-level taxon, variously named Unikonta, Amorphea or Opimoda.
Lobosa is a taxonomic group of amoebae in the phylum Amoebozoa. Most lobosans possess broad, bluntly rounded pseudopods, although one genus in the group, the recently discovered Sapocribrum, has slender and threadlike (filose) pseudopodia. In current classification schemes, Lobosa is a subphylum, composed mainly of amoebae that have lobose pseudopods but lack cilia or flagella.
Eumycetozoa, or true slime molds, is a diverse group of protists that behave as slime molds and develop fruiting bodies, either as sorocarps or as sporocarps. It is a monophyletic group or clade within the phylum Amoebozoa that contains the myxogastrids, dictyostelids and protosporangiids.
Dictyostelium discoideum is a species of soil-dwelling amoeba belonging to the phylum Amoebozoa, infraphylum Mycetozoa. Commonly referred to as slime mold, D. discoideum is a eukaryote that transitions from a collection of unicellular amoebae into a multicellular slug and then into a fruiting body within its lifetime. Its unique asexual life cycle consists of four stages: vegetative, aggregation, migration, and culmination. The life cycle of D. discoideum is relatively short, which allows for timely viewing of all stages. The cells involved in the life cycle undergo movement, chemical signaling, and development, which are applicable to human cancer research. The simplicity of its life cycle makes D. discoideum a valuable model organism to study genetic, cellular, and biochemical processes in other organisms.
Myxogastria/Myxogastrea or Myxomycetes (ICN), is a class of slime molds that contains 5 orders, 14 families, 62 genera, and 888 species. They are colloquially known as the plasmodial or acellular slime moulds.
Trichosphaerium is a genus of amoebozoan protists that present extraordinary morphological transformations, both in size and shape, during their life cycle. They can present a test that may or may not be covered in spicules. They are related to the family Microcoryciidae, which contains other amoebae with tests, within the clade Corycidia of the phylum Amoebozoa.
Trichiales is an order of slime moulds in the phylum Amoebozoa. Trichiales is one of five orders in the group Myxomycetes, or the true plasmodial slime molds. It is also currently categorized under the superorder Lucisporidia with its sister group, Liceales. The order was first described by Thomas MacBride in 1922, and has retained the same name and status as a defined order in present phylogeny. In the plasmodium form, members of Trichiales lack a columella but have a well-developed capillitium for spore dispersal. The shape and details of the capillitium are used to define families within the order. Spores are brightly coloured, ranging from clear, white and yellow to pink and red-brown tones. The order currently has 4 families, 14 genera and 174 species. Recent molecular research has shown that while Trichiales probably represents a true taxonomic group, its sister group Liceales is likely paraphyletic, and it has been suggested that several genera from the Liceales should be reclassified under Trichiales instead.
Tubifera is a genus of slime moulds from the subclass Myxogastria. The genus comprises 12 species.
Ceratiomyxa is a genus of plasmodial slime mould within the Eumycetozoa, first described by Pier Antonio Micheli. They are widely distributed and commonly found on decaying wood.
Fonticula is a genus of cellular slime mold which forms a fruiting body in a volcano shape. As long ago as 1979 it has been known to not have a close relationship with either the Dictyosteliida or the Acrasidae, the two well-established groups of cellular slime molds. In 1979, Fonticula was made a new genus of its own due to the unique characteristics of its fruiting body, with only one species: Fonticula alba.
Polysphondylium pallidum is a species of cellular slime mould, a member of the phylum Mycetozoa.
Barbeyella minutissima is a slime mould species of the order Echinosteliales, and the only species of the genus Barbeyella. First described in 1914 from the Jura mountains, its habitat is restricted to montane spruce and spruce-fir forests of the Northern Hemisphere, where it has been recorded from Asia, Europe, and North America. It typically colonises slimy, algae-covered logs that have lost their bark and have been partially to completely covered by liverworts. The sporangia are roughly spherical, up to 0.2 mm in diameter, and supported by a thin stalk up to 0.7 mm tall. After the spores have developed, the walls of the sporangia split open into lobes. The species is one of the smallest members of the Myxogastria and is considered rare.
Cutosea is a small group of marine amoeboid protists proposed in 2016. It is a monotypic class of Amoebozoa containing the order Squamocutida. Cutosean organisms are characterized by a cell coat of microscales separated from the cell membrane. Three genera, Armaparvus, Sapocribrum and Squamamoeba, belong to this group, distributed in two families.
Elaeomyxa is a genus of slime molds in the family Lamprodermataceae. As of May 2022, there are four known species in the genus. Species in this genus have been documented in North America, Eurasia, Africa, and Australasia.
Luapeleamoeba hula is a species of acanthamoebid amoeba described in 2016, capable of producing protosteloid fruiting bodies that consist of a stalk with one spore. It was obtained from dead māmaki leaves from the Manuka Natural Area Reserve in Hawai'i. It has also been found in the Democratic Republic of Congo.
Evosea is a diverse clade of amoeboid protists discovered through molecular analyses. Along with Tubulinea and Discosea, Evosea is one of the three major groups within Amoebozoa, an important clade of eukaryotic organisms. It contains unicellular organisms that display a wide variety of life cycles and cell shapes, including amoebae, flagellates and different kinds of slime molds.