| Mycetozoa | |
|---|---|
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| Aethalium of a slime mold ( Fuligo septica ) | |
Scientific classification  | |
| Domain: | Eukaryota |
| Phylum: | Amoebozoa |
| Subphylum: | Conosa |
| Infraphylum: | Mycetozoa de Bary, 1873 |
| Classes and orders | |
| Synonyms | |
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Mycetozoa is a polyphyletic grouping of slime molds. [2] It was originally thought to be a monophyletic clade, but recently it was discovered that protostelia are a polyphyletic group within Conosa. [3]
It can be divided into dictyostelid, myxogastrid, and protostelid groups. [4]
The mycetozoan groups all fit into the unikont supergroup Amoebozoa, whereas most other slime molds fit into various bikont groups (fonticulids are opisthokonts).
The dictyostelids are used as examples of cell communication and differentiation, and may provide insights into how multicellular organisms develop.
Physarum polycephalum are useful for studying cytoplasmic streaming. They have also been used to study the biochemical events that surround mitosis, since all of the nuclei in a medium-sized plasmodium divide in synchrony. It has been observed that they can find their way through mazes by spreading out and choosing the shortest path, an interesting example of information processing without a nervous system. Myxomycete plasmodia have also been used to study the genetics of asexual cell fusion. The giant size of the plasmodial cells allows for easy evaluation of complete or partial cell fusion.
In 2006, researchers at the University of Southampton and the University of Kobe reported that they had built a six-legged robot whose movement was remotely controlled by a Physarum slime mold. [5] The mold directed the robot into a dark corner most similar to its natural habitat.
Slime molds are sometimes studied in advanced mathematics courses. Slime mold aggregation is a natural process that can be approximated with partial differential equations.[ citation needed ]
Members of the Mycetozoa group are able to undergo sexual reproduction either by heterothallic or homothallic mating. [6] [7] [8] An analysis of meiosis-related genes in the Dictyostelium discoideum genome revealed that 36 of the 44 genes tested were present in the genome. [9] One gene, Spo11 , was absent in the Mycetozoa, raising questions about the assumed universal role of Spo11 as an initiator of meiosis. [9]
Slime mold or slime mould is an informal name given to several kinds of unrelated eukaryotic organisms that can live freely as single cells, but can aggregate together to form multicellular reproductive structures. Slime molds were formerly classified as fungi but are no longer considered part of that kingdom. Although not forming a single monophyletic clade, they are grouped within the paraphyletic group referred to as kingdom Protista.
The dictyostelids are a group of cellular slime molds, or social amoebae.
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 most classification schemes, Amoebozoa is 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. Most phylogenetic trees identify it as the sister group to Opisthokonta, another major clade which contains both fungi and animals as well as some 300 species of unicellular protists. Amoebozoa and Opisthokonta are sometimes grouped together in a high-level taxon, variously named Unikonta, Amorphea or Opimoda.
The opisthokonts are a broad group of eukaryotes, including both the animal and fungus kingdoms. The opisthokonts, previously called the "Fungi/Metazoa group", are generally recognized as a clade. Opisthokonts together with Apusomonadida and Breviata comprise the larger clade Obazoa.
Physarum polycephalum, an acellular slime mold or myxomycete popularly known as "the blob", is a protist with diverse cellular forms and broad geographic distribution. The “acellular” moniker derives from the plasmodial stage of the life cycle: the plasmodium is a bright yellow macroscopic multinucleate coenocyte shaped in a network of interlaced tubes. This stage of the life cycle, along with its preference for damp shady habitats, likely contributed to the original mischaracterization of the organism as a fungus. P. polycephalum is used as a model organism for research into motility, cellular differentiation, chemotaxis, cellular compatibility, and the cell cycle.
The family Acrasidae is a family of slime molds which belongs to the excavate group Percolozoa. The name element acrasio- comes from the Greek akrasia, meaning "acting against one's judgement". This group consists of cellular slime molds.
Lycogala epidendrum, commonly known as wolf's milk, groening's slime is a cosmopolitan species of myxogastrid amoeba which is often mistaken for a fungus. The aethalia, or fruiting bodies, occur either scattered or in groups on damp rotten wood, especially on large logs, from June to November. These aethalia are small, pink to brown cushion-like globs. They may excrete a pink paste if the outer wall is broken before maturity. When mature, the colour tends to become more brownish. When not fruiting, single celled individuals move about as very small, red amoeba-like organisms called plasmodia, masses of protoplasm that engulf bacteria, fungal and plant spores, protozoa, and particles of non-living organic matter through phagocytosis.
Spo11 is a protein that in humans is encoded by the SPO11 gene. Spo11, in a complex with mTopVIB, creates double strand breaks to initiate meiotic recombination. Its active site contains a tyrosine which ligates and dissociates with DNA to promote break formation. One Spo11 protein is involved per strand of DNA, thus two Spo11 proteins are involved in each double stranded break event.
Each species of slime mold has its own specific chemical messenger, which are collectively referred to as acrasins. These chemicals signal that many individual cells aggregate to form a single large cell or plasmodium. One of the earliest acrasins to be identified was cAMP, found in the species Dictyostelium discoideum by Brian Shaffer, which exhibits a complex swirling-pulsating spiral pattern when forming a pseudoplasmodium.
Multinucleate cells are eukaryotic cells that have more than one nucleus per cell, i.e., multiple nuclei share one common cytoplasm. Mitosis in multinucleate cells can occur either in a coordinated, synchronous manner where all nuclei divide simultaneously or asynchronously where individual nuclei divide independently in time and space. Certain organisms may have a multinuclear stage of their life cycle. For example, slime molds have a vegetative, multinucleate life stage called a plasmodium.
Cyclic AMP receptors from slime molds are a distinct family of G-protein coupled receptors. These receptors control development in Dictyostelium discoideum.
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 lifecycle consists of four stages: vegetative, aggregation, migration, and culmination. The lifecycle of D. discoideum is relatively short, which allows for timely viewing of all stages. The cells involved in the lifecycle undergo movement, chemical signaling, and development, which are applicable to human cancer research. The simplicity of its lifecycle makes D. discoideum a valuable model organism to study genetic, cellular, and biochemical processes in other organisms.
RNA, 5S cluster 1, also known as RN5S1@, is a human gene encoding the 5S subunit of ribosomal RNA.
Conosa is a grouping of Amoebozoa. It is subdivided into three groups – Archamoebae, Variosea (paraphyletic) and Mycetozoa (polyphyletic).
Protosteliomycetes/Protosteliales (ICBN) or Protostelea/Protostelia/Protosteliida (ICZN) is a grouping of slime molds from the phylum Mycetozoa. The name can vary depending upon the taxon used. Other names include Protostelea, Protostelia, and Protostelida. When not implying a specific level of classification, the term protostelid or protosteloid amoeba is sometimes used.
Myxogastria/Myxogastrea or Myxomycetes (ICBN), 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.
Differentiation-inducing factor (DIF) is one of a class of effector molecules that induce changes in cell chemistry, inhibiting growth and promoting differentiation of cell type. This name has been given to several factors before it was clear if they were the same or different effectors. More recently DIFs have garnered interest with their potential tumor inhibiting properties. DIFs have also been used to help regulate plant growth.
Bacillus subtilis is a rod-shaped, Gram-positive bacteria that is naturally found in soil and vegetation, and is known for its ability to form a small, tough, protective and metabolically dormant endospore. B. subtilis can divide symmetrically to make two daughter cells, or asymmetrically, producing a single endospore that is resistant to environmental factors such as heat, desiccation, radiation and chemical insult which can persist in the environment for long periods of time. The endospore is formed at times of nutritional stress, allowing the organism to persist in the environment until conditions become favourable. The process of endospore formation has profound morphological and physiological consequences: radical post-replicative remodelling of two progeny cells, accompanied eventually by cessation of metabolic activity in one daughter cell and death by lysis of the other.
An amoeba, often called an amoeboid, is a type of cell or unicellular organism which has the ability to alter its shape, primarily by extending and retracting pseudopods. Amoebae do not form a single taxonomic group; instead, they are found in every major lineage of eukaryotic organisms. Amoeboid cells occur not only among the protozoa, but also in fungi, algae, and animals.
 | Wikimedia Commons has media related to Mycetozoa . |
 | Wikisource has the text of the 1911 Encyclopædia Britannica article Mycetozoa . |
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