''Mucor'' is a microbial genus of approximately 40 species of molds and dimorphic fungi in the family Mucoraceae. The genus includes both pathogenic and avirulent species, and some members of it can be utilized in biotechnical applications. These fungi are commonly found in

soil Soil, also commonly referred to as earth, is a mixture of organic matter, minerals, gases, water, and organisms that together support the life of plants and soil organisms. Some scientific definitions distinguish dirt from ''soil'' by re ...

digestive system The human digestive system consists of the gastrointestinal tract plus the accessory organs of digestion (the tongue, salivary glands, pancreas, liver, and gallbladder). Digestion involves the breakdown of food into smaller and smaller compone ...

plant Plants are the eukaryotes that form the Kingdom (biology), kingdom Plantae; they are predominantly Photosynthesis, photosynthetic. This means that they obtain their energy from sunlight, using chloroplasts derived from endosymbiosis with c ...

surfaces, some cheeses like

Tomme de Savoie Tomme de Savoie () is an uplandJoel Robuchon et al., ''Larousse Gastronomique'' (New York, New York: Clarkson Potter, 2001), page 1220. variety of Tomme cheese, specifically, one from Savoy in the French Alps. It is a mild, semi-firm cow's mil ...

, rotten vegetable matter and

iron oxide An iron oxide is a chemical compound composed of iron and oxygen. Several iron oxides are recognized. Often they are non-stoichiometric. Ferric oxyhydroxides are a related class of compounds, perhaps the best known of which is rust. Iron ...

residue in the biosorption process.

Description

Colonies of this fungal genus are typically yellow, beige or grey. They are characterized by rapid growth and sporulation in high a_w environments, and they reproduce both sexually and asexually. ''Mucor''

spores In biology, a spore is a unit of sexual (in fungi) or asexual reproduction that may be adapted for dispersal and for survival, often for extended periods of time, in unfavourable conditions. Spores form part of the life cycles of many plant ...

or sporangiospores can be simple or branched and form apical, globular

sporangia A sporangium (from Late Latin, ; : sporangia) is an enclosure in which spores are formed. It can be composed of a unicellular organism, single cell or can be multicellular organism, multicellular. Virtually all plants, fungus, fungi, and many ot ...

that are supported and elevated by a column-shaped columella. ''Mucor'' species can be differentiated from molds of the genera ''

Absidia ''Absidia'' is a genus of fungi in the family Cunninghamellaceae. ''Absidia'' species are ubiquitous in most environments where they are often associated with warm decaying plant matter, such as compost heaps. Some species in the genus can caus ...

'', '' Rhizomucor'', and ''

Rhizopus ''Rhizopus'' is a genus of common saprophytic fungi on plants and specialized parasites on animals. They are found in a wide variety of organic substances, including "mature fruits and vegetables", jellies, syrups, leather, bread, peanuts, and t ...

'' by the shape and insertion of the columella, and the lack of

stolon In biology, a stolon ( from Latin ''wikt:stolo, stolō'', genitive ''stolōnis'' – "branch"), also known as a runner, is a horizontal connection between parts of an organism. It may be part of the organism, or of its skeleton. Typically, animal ...

s and

rhizoid Rhizoids are protuberances that extend from the lower epidermal cells of bryophytes and algae. They are similar in structure and function to the root hairs of vascular land plants. Similar structures are formed by some fungi. Rhizoids may be un ...

s. Some ''Mucor'' species produce chlamydospores. They form mold with irregular non-septate hyphae branching at wide angles (>90°).

Reproduction

''Mucor mucedo'' (type species) use asexual reproduction. When erect hyphal sporangiophores are formed, the tip of the sporangiophore swells to form a globose sporangium that contains uninucleate, haploid sporangiospores. An extension of the sporangiophore called the columella protrudes into the sporangium. The sporangium walls are easily ruptured to release the spores, which germinate readily to form a new mycelium on appropriate substrates. During sexual reproduction, compatible strains form short, specialized hyphae called ''gametangia''. At the point where two complementary gametangia fuse, a thick-walled, spherical zygosporangium develops. The zygosporangium typically contains a single zygospore. Nuclear

karyogamy Karyogamy is the final step in the process of fusing together two haploid eukaryotic cells, and refers specifically to the fusion of the two cell nucleus, nuclei. Before karyogamy, each haploid cell has one complete copy of the organism's genome. ...

and

meiosis Meiosis () is a special type of cell division of germ cells in sexually-reproducing organisms that produces the gametes, the sperm or egg cells. It involves two rounds of division that ultimately result in four cells, each with only one c ...

(sexual recombination) occur within it.

Clinical significance

Most species of ''Mucor'' are unable to cause disease in humans and

endothermic An endothermic process is a chemical or physical process that absorbs heat from its surroundings. In terms of thermodynamics, it is a thermodynamic process with an increase in the enthalpy (or internal energy ) of the system.Oxtoby, D. W; Gillis, ...

animals due to their inability to grow at temperatures around 37 °C. But some thermotolerant species such as ''

Mucor circinelloides ''Mucor circinelloides'' is a dimorphic fungus belonging to the Order Mucorales (Phylum Mucoromycota). It has a worldwide distribution, found mostly in soil, dung and root vegetables. This species is described as not known to be able to produce ...

, M. irregularis'' and '' M. hiemalis'' can cause

mucormycosis Mucormycosis, also known as black fungus, is a severe fungal infection that comes under fulminant fungal sinusitis, usually in people who are immunocompromised. It is curable only when diagnosed early. Symptoms depend on where in the body the ...

, an acute and invasive fungal infection effecting primarily

immunocompromised Immunodeficiency, also known as immunocompromise, is a state in which the immune system's ability to fight infectious diseases and cancer is compromised or entirely absent. Most cases are acquired ("secondary") due to extrinsic factors that affe ...

hosts. Many ''Mucor'' species fungi are intrinsically resistant to most available antifungals, which causes issues in treatment of this disease. The available treatment options all target the

ergosterol Ergosterol (ergosta-5,7,22-trien-3β-ol) is a mycosterol found in cell membranes of fungi and protozoa, serving many of the same functions that cholesterol serves in animal cells. Because many fungi and protozoa cannot survive without ergostero ...

biosynthesis pathway of these fungi, and mutations in genes transcribing enzymes for it have been linked to resistance development towards the primary treatment option for the disease.

Selected species

* '' M. amphibiorum'' * '' M. circinelloides'' * '' M. ellipsoideus'' * '' M. fragilis'' * '' M. hiemalis'' * ''M. hiemalis'' f. ''silvaticus'' * '' M. indicus'' * ''M. irregularis'' * '' M. mucedo'' * '' M. paronychius'' * '' M. piriformis'' * '' M. plumbeus'' * '' M. pseudolusitanicus'' * '' M. racemosus'' * '' M. ramosissimus'' * '' M. variicolumellatus'' * '' M. velutinosus''

References

External links

* *
Mucor
at Zygomycetes.org
''Mucor'' species
from Index Fungorum
''Mucor'' page
from Index Fungorum {{Authority control Mucoraceae Zygomycota genera