Rhodotorula glutinis

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Rhodotorula glutinis
Rhodotorula glutinis.jpg
Scientific classification
Kingdom:
Fungi
Division:
Basidiomycota
Class:
Microbotryomycetes
Order:
Sporidiobolales
Genus:
Rhodotorula
Species:
R. glutinis
Binomial name
Rhodotorula glutinis
(Fresen.) F.C. Harrison (1928)
Synonyms
  • Cryptococcus glutinis Fresen. (1852)
  • Saccharomyces glutinis (Fresen.) Cohn (1872)
  • Torula glutinis (Fresen.) Pringsh. & Bilewsky (1911)
  • Rhodotorula terrea Sugiy. & Goto (1969)

Rhodotorula glutinis is the type species of the genus Rhodotorula , a basidiomycetous genus of pink yeasts which contains 370 species. Heterogeneity of the genus has made its classification difficult with five varieties having been recognized; however, as of 2011, all are considered to represent a single taxon. [1] The fungus is a common colonist of animals, foods and environmental materials. It can cause opportunistic infections, notably blood infection in the setting of significant underlying disease. It has been used industrially in the production of carotenoid pigments and as a biocontrol agent for post-harvest spoilage diseases of fruits.

Contents

Growth and morphology

R. glutinis is an aerobic yeast characterized by pink, smooth colonies with a moist appearance. [2] Reproduction is typically by multipolar budding although pseudohyphae are occasionally produced. Sexual reproduction is by basidiospores arising from a teliospore developed from a mycelial clamp connection. [2] A distinguishing feature of the species and its close relatives are the intense yellow and red pigments produced during growth on most substrates.[ citation needed ]

It normally grows at 37 °C at a rapid rate, and requires a minimum water activity of 0.92, pH of 2.2, and organic acids or HCl. [2] [3] Growth is inhibited by 100 mg/kg or less of benzoic acid or sorbic acid and a pH of 4 or above. [3] The fungus is unable to grow on malt acetic agar or MY50G medium. [3] At maturity, the cells reach a diameter of 3-5 µm and are round, oval, or elongate in shape, aggregating as mucoid colonies. [2] [4] Carbohydrates in the cell include glucose, fucose, galactose, and mannose. [1] R. glutinis is heat resistant, an uncommon feature in yeasts without spores, tolerating 62.5 °C (144.5 °F) for 10 minutes. [3] R. glutinis is closely related to Rhodotorula mucilaginosa, differing only in their ability to use nitrate as a nitrogen source, which R. glutinis cannot assimilate. [3] Both species are incapable of fermentation and assimilation of Myo-Inositol and D-glucoronate. [1] [5] [4]

Standard microbiological methods of identification have misidentified Candida auris as Rhodotorula glutinis, until sequence analysis correctly identified C. auris as such. [6]

The genome of R. glutinis is CG-rich, containing up to 67% GC by base composition. [1]

Habitat and ecology

R. glutinis is distributed widely, most often found in soil, air and throughout the phyllosphere. Accordingly, it is not uncommon to recover it in cultures of cereals, flour, malting barley, dough, citrus products, olives and soaking soybeans. [3] It is frequently isolated from foods. [2] Due to its rapid growth at refrigerator temperatures, it is encountered sometimes as a spoilage agent in dairy products such as yogurts, cheeses, butter, and fresh and processed meats, vegetables and seafoods. [3] It has also been reported from blotched frozen peas stored at 0 °C (32 °F) for 8 weeks with yeast burden increasing significantly after 24 weeks at −18 °C (0 °F), suggesting an ability to proliferate at temperatures below freezing. [3] The fungus is a commensal of mammals including humans, occurring commonly on skin and is found in stool. [7]

Industrial applications

There has been increasing interest and development in the biotechnological applications of R. glutinis over recent[ when? ] years. The fungus produces carotenoids, such as beta-Carotene and torularhodin, which animals cannot synthesize on their own. [8] In the yeast, carotenoids act as a protective agent against visible light and harmful metabolic oxygen species. [8] Carotenoids are valuable in wastewater treatment, enzyme production, pharmaceuticals, and even tumour inhibition. [8] Because the fungus exhibits rapid growth and is ostensibly single-celled, it is a potential candidate for large-scale manufacturing. [8] Given a suitable culture medium, an optimal yield of carotenoid could in theory be attained from cheap substrates such as beet molasses, peat extract, and grape must. [8] [9] An R. glutinis mutant (NCIM 3253) was shown to produce 76-fold more b-carotene than their wild type relatives, [8] suggesting that these microorganisms may have a role in cost-effective, high yield manufacture of carotenoids. Recent studies have also shown that 16 strains of R. glutinis possess antibacterial and antioxidant properties, although it is unclear if the fungus could be used to manufacture these materials on a commercially viable scale. [10]

R. glutinis has been investigated as a biocontrol agent of post-harvest disease of fruits. Pretreatment of apples and oranges with R. glutinis effectively reduced or prevented blue mold ( Penicillium expansum ) and grey mold ( Botrytis cinerea ), lengthening the shelf life of these fruits without reducing fruit quality. [11] The yeast is thought to inhibit post-spoilage rot by competing with spoilage agents for space and nutrients, i.e. competitive inhibition. [11] An inoculum of R. glutinis remains viable in storage at 20 °C (68 °F) for 5 days, supporting its potential as a stable biocontrol agent. [11]

Pathogenicity

R. glutinis is the second most common disease-causing species of Rhodotorula following R. mucilaginosa. [12] Infections have been observed worldwide, though nearly half of all reported infections have originated in the Asia-Pacific region. [13]

It was not until 1985, that species of Rhodotorula had been first reported in human colonization and infection. [12] Its occasional recovery from stool has led to the suggestion that it exists as a periodic, clinically insignificant colonist of the distal gut. [12] Rhodotorula species are the most commonly isolated yeasts found on hands of hospital workers, suggesting a potential reservoir for the agent. [12] [14]

This observation, combined with its high tolerance for extreme conditions may partially explain its rare appearance as an opportunistic agent of blood infection in seriously ill people. The majority of cases are systemic in nature, often causing fungemia in patients with underlying disease or immunosuppression, such as cancer or leukemia, and transplant and AIDS patients most likely to develop systemic infection. [12] [13] The incidence correlates with the rising use of intensive medical therapies and central venous catheters. Infection may be linked to venous catheter contamination due to the strong affinity of this species for plastic. [12] Although reports of systemic infections predominate, localized infection has been reported as well, including meningitis and peritonitis absent overt immunosuppression or CVC. [12]

R. glutinis is highly drug resistant to most antifungal agents, but successful treatment has been achieved with amphotericin B. [13]

Related Research Articles

<span class="mw-page-title-main">Yeast</span> Informal group of fungi

Yeasts are eukaryotic, single-celled microorganisms classified as members of the fungus kingdom. The first yeast originated hundreds of millions of years ago, and at least 1,500 species are currently recognized. They are estimated to constitute 1% of all described fungal species.

<i>Candida</i> (fungus) Genus of ascomycete fungi

Candida is a genus of yeasts. It is the most common cause of fungal infections worldwide and the largest genus of medically important yeast.

<span class="mw-page-title-main">Astaxanthin</span> Chemical compound

Astaxanthin is a keto-carotenoid within a group of chemical compounds known as terpenes. Astaxanthin is a metabolite of zeaxanthin and canthaxanthin, containing both hydroxyl and ketone functional groups. It is a lipid-soluble pigment with red coloring properties, which result from the extended chain of conjugated double bonds at the center of the compound. The presence of the hydroxyl functional groups and the hydrophobic hydrocarbons render the molecule amphiphilic.

<span class="mw-page-title-main">Fungemia</span> Internal, blood-borne infection by fungi, including yeasts.

Fungemia is the presence of fungi or yeasts in the blood. The most common type, also known as candidemia, candedemia, or systemic candidiasis, is caused by Candida species; candidemia is also among the most common bloodstream infections of any kind. Infections by other fungi, including Saccharomyces, Aspergillus and Cryptococcus, are also called fungemia. It is most commonly seen in immunosuppressed or immunocompromised patients with severe neutropenia, cancer patients, or in patients with intravenous catheters. It has been suggested that otherwise immunocompetent patients taking infliximab may also be at a higher risk for fungemia.

Candida parapsilosis is a fungal species of yeast that has become a significant cause of sepsis and of wound and tissue infections in immunocompromised people. Unlike Candida albicans and Candida tropicalis, C. parapsilosis is not an obligate human pathogen, having been isolated from nonhuman sources such as domestic animals, insects and soil. C. parapsilosis is also a normal human commensal and it is one of the fungi most frequently isolated from human hands. There are several risk factors that can contribute to C. parapsilosis colonization. Immunocompromised individuals and surgical patients, particularly those undergoing surgery of the gastrointestinal tract, are at high risk for infection with C. parapsilosis. There is currently no consensus on the treatment of invasive candidiasis caused by C. parapsilosis, although the therapeutic approach typically includes the removal of foreign bodies such as implanted prostheses and the administration of systemic antifungal therapy. Amphotericin B and Fluconazole are often used in the treatment of C. parapsilosis infection.

<i>Rhodotorula</i> Genus of fungi

Rhodotorula is a genus of fungi in the class Microbotryomycetes. Most species are known in their yeast states which produce orange to red colonies when grown on Sabouraud's dextrose agar (SDA). The colour is the result of pigments that the yeast creates to block out certain wavelengths of light (620–750 nm) that would otherwise be damaging to the cell. Hyphal states, formerly placed in the genus Rhodosporidium, give rise to teliospores from which laterally septate basidia emerge, producing sessile basidiospores. Species occur worldwide and can be isolated from air, water, soil, and other substrates.

<i>Malassezia furfur</i> Species of fungus

Malassezia furfur is a species of yeast that is naturally found on the skin surfaces of humans and some other mammals. It is associated with a variety of dermatological conditions caused by fungal infections, notably seborrhoeic dermatitis and tinea versicolor. As an opportunistic pathogen, it has further been associated with dandruff, malassezia folliculitis, pityriasis versicolor (alba), and malassezia intertrigo, as well as catheter-related fungemia and pneumonia in patients receiving hematopoietic transplants. The fungus can also affect animals, including dogs.

<i>Aureobasidium pullulans</i> Species of fungus

Aureobasidium pullulans is a ubiquitous and generalistic black, yeast-like fungus that can be found in different environments. It is well known as a naturally occurring epiphyte or endophyte of a wide range of plant species without causing any symptoms of disease. A. pullulans has a high importance in biotechnology for the production of different enzymes, siderophores and pullulan. Furthermore, A. pullulans is used in biological control of plant diseases, especially storage diseases.

<i>Blakeslea trispora</i> Species of fungus

Blakeslea trispora is a mould and member of the division Zygomycota. This species has been well studied for its ability to produce carotenoids, particularly, β-carotene and lycopene. β-carotene is a vitamin A precursor and both of β-carotene and lycopene play a significant role in the inhibition of oxidative stress. Blakeslea trispora is commonly isolated from soil samples throughout the Southern United States and Southern Asia. B. trispora is a pathogen of tropical plants. In vivo pathogenicity testing using animal models suggests this fungus is not a cause of animal or human disease.

Pathogenic fungi are fungi that cause disease in humans or other organisms. Although fungi are eukaryotic, many pathogenic fungi are microorganisms. Approximately 300 fungi are known to be pathogenic to humans; their study is called "medical mycology". Fungal infections kill more people than either tuberculosis or malaria—about 2 million people per year.

<span class="mw-page-title-main">Rhodotorulic acid</span> Chemical compound

Rhodotorulic acid is the smallest of the 2,5-diketopiperazine family of hydroxamate siderophores which are high-affinity chelating agents for ferric iron, produced by bacterial and fungal phytopathogens for scavenging iron from the environment. It is a tetradentate ligand, meaning it binds one iron atom in four locations (two hydroxamate and two lactam moieties), and forms Fe2(siderophore)3 complexes to fulfill an octahedral coordination for iron.

<span class="mw-page-title-main">Sporidiobolales</span> Order of fungi

The Sporidiobolales are an order of fungi in the subdivision Pucciniomycotina. The order contains a single family, the Sporidiobolaceae, which currently contains three genera. Most species are known only from their yeast states. Hyphal states produce teliospores from which auricularioid basidia emerge, bearing basidiospores. Species occur worldwide and have been isolated from a wide variety of substrates. Two species, Rhodotorula mucilaginosa and R. glutinis, have been known to cause disease in humans.

<i>Candida auris</i> Species of fungus

Candida auris is a species of fungus that grows as yeast. It is one of the few species of the genus Candida which cause candidiasis in humans. Often, candidiasis is acquired in hospitals by patients with weakened immune systems. C. auris can cause invasive candidiasis (fungemia) in which the bloodstream, the central nervous system, and internal organs are infected. It has attracted widespread attention because of its multiple drug resistance. Treatment is also complicated because it is easily misidentified as other Candida species.

<i>Cunninghamella echinulata</i> Species of fungus

Cunninghamella echinulata is a fungal species in the genus Cunninghamella. It is an asexually reproducing fungus and a mesophile, preferring intermediate temperature ranges. C. echinulata is a common air contaminant, and is currently of interest to the biotechnology industry due to its ability to synthesize γ-linolenic acid as well as its capacity to bioconcentrate metals. This species is a soil saprotroph that forms rhizoids, preferring soils enriched in nitrogen, phosphorus and potassium. It has been reported occasionally an agent of mucormycosis following the inhalation of fungal spores. Czapek's agar is a suitable growth medium for the propagation of C. echinulata.

<i>Aspergillus tubingensis</i> Species of fungus

Aspergillus tubingensis is a darkly pigmented species of fungus in the genus Aspergillus section Nigri. It is often confused with Aspergillus niger due to their similar morphology and habitat. A. tubingensis is often involved in food spoilage of fruits and wheat, and industrial fermentation. This species is a rare agent of opportunistic infection.

Invasive candidiasis is an infection (candidiasis) that can be caused by various species of Candida yeast. Unlike Candida infections of the mouth and throat or vagina, invasive candidiasis is a serious, progressive, and potentially fatal infection that can affect the blood (fungemia), heart, brain, eyes, bones, and other parts of the body.

<i>Phialemonium obovatum</i> Species of fungus

Phialemonium obovatum is a saprotrophic filamentous fungus able to cause opportunistic infections in humans with weakened immune systems. P. obovatum is widespread throughout the environment, occurring commonly in sewage, soil, air and water. Walter Gams and Michael McGinnis described the genus Phialemonium to accommodate species intermediate between the genera Acremonium and Phialophora. Currently, three species of Phialemonium are recognized of which P. obovatum is the only one to produce greenish colonies and obovate conidia. It has been investigated as one of several microfungi with potential use in the accelerated aging of wine.

<span class="mw-page-title-main">Trichosporon asteroides</span> Fungus of the genus Trichosporon

Trichosporon asteroides is an asexual basidiomycetous fungus first described from human skin but now mainly isolated from blood and urine. T. asteroides is a hyphal fungus with a characteristically yeast-like appearance due to the presence of slimy arthroconidia. Infections by this species usually respond to treatment with azoles and amphotericin B.

Candida catenulata is a yeast-form fungus in the phylum Ascomycota. It is distributed globally and commonly found on the skin of humans and animals, in soil, and in dairy products.

Candida haemulonii is a yeast fungal pathogen that is known to cause infections in humans. C. haemulonii is an emerging opportunistic pathogen that is found in hospitals and healthcare settings. Infections are difficult to treat because the fungus has resistance to antifungal agents. Since its emergence, little research has been conducted on this fungus. However, in recent years, research has been conducted to help identify the various properties of C. haemulonii.

References

  1. 1 2 3 4 Kurtzman C, Fell JW, Boekhout T (2011). The Yeasts: A Taxonomic Study (5th ed.). Elsevier. ISBN   978-0-08-093127-2.
  2. 1 2 3 4 5 Hernández-Almanza A, Montanez JC, Aguilar-Gonzalez MA, Martínez-Ávila C, Rodríguez-Herrera R, Aguilar CN (March 2014). "Rhodotorula glutinis as source of pigments and metabolites for food industry". Food Biosciences. 5: 64–72. doi:10.1016/j.fbio.2013.11.007.
  3. 1 2 3 4 5 6 7 8 Pitt JI, Hocking AD (1999). Fungi and food spoilage (2nd ed.). Gaithersburg, Md.: Aspen Publications. ISBN   0-8342-1306-0.
  4. 1 2 Barron GL (1968). The genera of Hyphomycetes from soil. Baltimore, MD: Williams & Wilkins. ISBN   978-0-88275-004-0.
  5. ↑ Samson RA, Hoekstra ES, Frisvad JC (2004). Introduction to food- and airborne fungi (7th ed.). Washington, DC: ASM Press. ISBN   9070351528.
  6. ↑ Lee WG, Shin JH, Uh Y, Kang MG, Kim SH, Park KH, Jang HC (September 2011). "First three reported cases of nosocomial fungemia caused by Candida auris". Journal of Clinical Microbiology. 49 (9): 3139–42. doi:10.1128/JCM.00319-11. PMC   3165631 . PMID   21715586.
  7. ↑ Reiss E, Jean H, Marshall-Lyon G (2012). Fundamental Medical Mycology. Hoboken, NJ: Wiley-Blackwell. ISBN   978-0-470-17791-4.
  8. 1 2 3 4 5 6 Cong L, Chi Z, Li J, Wang X (January 2007). "Enhanced carotenoid production by a mutant of the marine yeast Rhodotorula sp. hidai". Journal of Ocean University of China. 6 (1): 66–71. Bibcode:2007JOUC....6...66C. doi:10.1007/s11802-007-0066-x. S2CID   83806277.
  9. ↑ Bhosale P, Gadre RV (June 2001). "β-Carotene production in sugarcane molasses by a Rhodotorula glutinis mutant". Journal of Industrial Microbiology & Biotechnology. 26 (6): 327–332. doi: 10.1038/sj.jim.7000138 . PMID   11571614.
  10. ↑ Keceli TM, Erginkaya Z, Turkkan E, Kaya U (January 2013). "Antioxidant and Antibacterial Effects of Carotenoids Extracted from Rhodotorula glutinis Strains". Asian Journal of Chemistry. 25 (1): 42–46. doi: 10.14233/ajchem.2013.12377 . Retrieved 15 October 2015.
  11. 1 2 3 Zhang H, Wang L, Ma L, Dong Y, Jiang S, Xu B, Zheng X (January 2009). "Biocontrol of major postharvest pathogens on apple using Rhodotorula glutinis and its effects on postharvest quality parameters". Biological Control. 48 (1): 79–83. doi:10.1016/j.biocontrol.2008.09.004.
  12. 1 2 3 4 5 6 7 Wirth F, Goldani LZ (September 2012). "Epidemiology of Rhodotorula: an emerging pathogen". Interdisciplinary Perspectives on Infectious Diseases. 2012: 465717. doi: 10.1155/2012/465717 . PMC   3469092 . PMID   23091485.
  13. 1 2 3 Miceli MH, Díaz JA, Lee SA (February 2011). "Emerging opportunistic yeast infections". The Lancet. Infectious Diseases. 11 (2): 142–51. doi:10.1016/S1473-3099(10)70218-8. PMID   21272794.
  14. ↑ Strausbaugh LJ, Sewell DL, Tjoelker RC, Heitzman T, Webster T, Ward TT, Pfaller MA (February 1996). "Comparison of three methods for recovery of yeasts from hands of health-care workers". Journal of Clinical Microbiology. 34 (2): 471–3. doi:10.1128/jcm.34.2.471-473.1996. PMC   228825 . PMID   8789043.
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