Mucor circinelloides | |
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Scientific classification ![]() | |
Domain: | Eukaryota |
Kingdom: | Fungi |
Division: | Mucoromycota |
Class: | Mucoromycetes |
Order: | Mucorales |
Family: | Mucoraceae |
Genus: | Mucor |
Species: | M. circinelloides |
Binomial name | |
Mucor circinelloides Tieghem (1875) | |
Synonyms | |
Mucor circinelloides is a dimorphic fungus [1] 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 mycotoxins, [2] however it has been frequently reported to infect animals such as cattle and swine, as well as fowl, platypus and occasionally humans. [3] [4] Ketoacidotic patients are particularly at risk for infection by M. circinelloides. [3]
Mucor circinelloides is one of the common species in the genus Mucor. [5] Mucor circinelloides is a variable species that include several variants such as; M. circinelloides f. circinelloides; M. circinelloides f. lusitanicus; M. circinelloides f. griseocyanus and M. circinelloides f. janssenii. [6]
Mucor circinelloides reproduce both asexually and sexually [7] . The asexual sporangiophores are found as two types: elongate and sympodially branched. [6] The elongate sporangiophores have larger sporangia, which are white at first and progressively turn greenish brown in colour. [6] They assume a globose shape and are 40–80 μm in size; characterized as "bobbing heads". [6] Sporangiophores are mostly sympodially branched [5] with small sporangia (25 μm); [6] branches are and sometimes circinate. [8] The diameter of the sporangia range from 20 to 80 μm. [8] Sporangia have slightly encrusted walls. [5] In larger sporangia, the membranes are deliquescent, whereas they are persistent in the smaller ones and rupture at maturity. [8] [5] Smaller sporangia also have smooth persistent walls. [6] Sporangiophores are ellipsoid (6–7 μm in diameter) or subglobose (4–6 μm in diameter). [8] Numerous chlamydospores are also produced. [5]
Colonies are fast growing and go up to 2 cm in height. [6] On Czapek Yeast Autolysate (CYA) plates, the colony growth is low and sparse, most often spreading across the entire Petri dish. [2] These colonies of 60 mm diameter or more appear to be pale grey or yellow in colour, with the reverse being uncoloured. [2] Colonies also fill up the entire Petri dish of malt extract agar, producing colony colours similar to those observed on CYA. [2] Mucor circinelloides can assume a yeast-like growth form. [6] It has been isolated in this yeast form from human urine and normal stool specimen. [6] It has also been recovered as a yeast from frogs. [6]
Mucor circinelloides has good growth and sporulation between 5–10 °C [4] [5] and very poor growth at 37 °C which is also the maximum growth temperature. [5] [3] The minimal water activity(aw) for growth is 0.9. [4] M. circinelloides assimilates ethanol and nitrate. [3] The length and number of tall sporangiophores decrease with lower temperatures. [4] Spores are broadly ellipsoid (4.4-6.8 x 3.7-4.7 μm [5] Growth, sporulation, and presence of tall and short sporangiophores can be influenced by temperature; however sporangiophore shape, size and uniformity are not influenced by temperatures. [4]
At least 20 species belonging to the genus Mucor are found to be extracted from food. [4] M. circinelloides is one of the five most significant fungus out of these 20 along with M. hiemalis, M. piriformis, M. plumbeus and M. racemosus. [4] It has been reported to spoil cheese and yams as well as diseases of mango. [2] This fungus has also been isolated from various foods such as meat, hazelnuts, walnuts, maize, mung beans, soybeans and barley. [2]
Fungi in the order Mucorales class have not been investigated in detail for their ability to produce mycotoxins; [9] Cytotoxicity and mycotoxin-production was analysed and tested for using the cytotoxicity test (MTT assay) and LC/MS/MS-based multimycotoxin method respectively for three fungal species, including M. circinelloides. [9] Mucor circinelloides was found to be able to produce 3-nitropropionic acid as well as have low cytotoxicity. [9] Conventionally, M. circinelloides is considered not to produce mycotoxins. [2]
Mucor circinelloides is considered an emerging pathogen, although it has only been associated rarely with very human disease and have been limited to cutaneous infection. [10] This species is occasionally isolated from humans, birds, cattle, and swine. [6]
Mucor circinelloides is potentially a rich source of antioxidants and other secondary metabolites which could be used in the development of nutraceuticals and natural antioxidants. [11]