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 | |
|---|---|
| |
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 | |
History and taxonomy
editMucor 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]
Growth and morphology
editMucor circinelloides reproduce asexually. The 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.[7] The diameter of the sporangia range from 20 to 80 μm.[7] 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.[7][5] Smaller sporangia also have smooth persistent walls.[6] Sporangiophores are ellipsoid (6–7 μm in diameter) or subglobose (4–6 μm in diameter).[7] 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]
Physiology
editMucor 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]
Habitat and ecology
editAt 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;[8] 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.[8] Mucor circinelloides was found to be able to produce 3-nitropropionic acid as well as have low cytotoxicity.[8] Conventionally, M. circinelloides is considered not to produce mycotoxins.[2]
Pathogenicity
editMucor circinelloides is considered an emerging pathogen, although it has only been associated rarely with very human disease and have been limited to cutaneous infection.[9] This species is occasionally isolated from humans, birds, cattle, and swine.[6]
Antioxidant potential
editMucor circinelloides is potentially a rich source of antioxidants and other secondary metabolites which could be used in the development of nutraceuticals and natural antioxidants.[10]
References
edit- ^ Lubbenhusen, T.L; Nielsen, J.; McIntyre, M. (2003). "Characterization of the Mucor circinelloides life cycle by on-line image analysis". J Appl Microbiol. 95 (5): 1152–60. doi:10.1046/j.1365-2672.2003.02098.x. PMID 14633045.
- ^ a b c d e f g Pitt, J.I.; Hocking, A.D. (1999). Fungi and food spoilage (2nd ed.). Gaithersburg, Md.: Aspen Publications. ISBN 0-8342-1306-0.
- ^ a b c d de Hoog, G.S; Guarro, J.; Gene, J.; Figueras, M.J (2000). Atlas of clinical fungi (2nd ed.). Utrecht: Centraalbureau voor Schimmelcultures [u.a.] ISBN 90-70351-43-9.
- ^ a b c d e f g Samson, R.A; Hoekstra, E.S; Frisvad, J.C; Filtenbog, Ole (2000). Introduction to food- and airborne fungi (6th rev. ed.). Utrecht: Centraalbureau voor Schimmelcultures. ISBN 90-70351-42-0.
- ^ a b c d e f g h Watanabe, Tsuneo (2009). Pictorial atlas of soil and seed fungi : morphologies of cultured fungi and key to species (3rd ed.). Boca Raton, Fla.: CRC. ISBN 978-1-4398-0419-3.
- ^ a b c d e f g h i j k Rippon, John Willard (1988). Medical mycology : the pathogenic fungi and the pathogenic actinomycetes (3rd ed.). Philadelphia: W.B. Saunders Co. ISBN 0-7216-2444-8.
- ^ a b c d Howard, D.H (2003). Pathogenic Fungi in Humans and Animals (3rd ed.). United States of America: Marcel Dekker, Inc. ISBN 9780824706838.
- ^ a b c Hollmann, M.; Razzazi-Fazeli, E.; Grajewski, J.; Twaruzek, M/; Sulyok, M.; Bohm, J. (2008). "Detection of 3-nitropropionic acid and cytoxicity in Mucor circinelloides". Mycotoxin Research. 24 (3): 140–150. doi:10.1007/BF03032341. PMID 23604749.
- ^ Murray, [American Society for Microbiology]. Ed. in chief Patrick R. (1999). Manual of clinical microbiology (7th ed.). Washington, DC: ASM Press. ISBN 1-55581-126-4.
- ^ Hameed, Ahsan; Hussain, Syed Ammar; Yang, Junhuan; Ijaz, Muhammad Umair; Liu, Qing; Suleria, Hafiz Ansar Rasul; Song, Yuanda (2017-10-07). "Antioxidants Potential of the Filamentous Fungi (Mucor circinelloides)". Nutrients. 9 (10): 1101. doi:10.3390/nu9101101. PMC 5691717. PMID 28991177.