Geomyces pannorum is a yellow-brown filamentous fungus of the phylum Ascomycota commonly found in cold soil environments including the permafrost of the Northern hemisphere. [1] A ubiquitous soil fungus, it is the most common species of the genus Geomyces ; which also includes G. vinaceus and G. asperulatus. [2] [3] Geomyces pannorum has been identified as an agent of disfigurement of pigments used in the 15,000-year-old paintings on the walls of the Lascaux caves of France. [4] Strains of Geomyces have been recovered from the Alaskan Fox Permafrost Tunnel and radiocarbon dated to between 14,000 and 30,000 years old. [5]
Geomyces pannorum | |
---|---|
![]() | |
Scientific classification | |
Kingdom: | |
Division: | |
Subphylum: | |
Class: | |
Order: | |
Family: | |
Genus: | |
Species: | G. pannorum |
Binomial name | |
Geomyces pannorum (Link) Sigler & J.W. Carmich. (1976) | |
Synonyms | |
The fungus Geomyces pannorum was originally described as Sporotrichum pannorum from rotten cloth in Germany by Johann Heinrich Friedrich Link in 1824. [3] It was transferred to the genus Chrysosporium by the Canadian mycologist Stanley Hughes in 1958; however, the asymmetry and relatively small size of the conidia combined with the tree-like, branched appearance of the asexual reproductive structures suggested it belonged elsewhere. [6] [7] In 1976 the fungus was transferred to the genus Geomyces as Geomyces pannorum by Canadian mycologists Lynne Sigler and John William Carmichael. [7]
Geomyces pannorum is a temperate soil fungus often associated with cold temperatures. It has been isolated from Arctic permafrost as well as the soils of Antarctica. [8] [9] Geomyces pannorum has also been recovered from glacier bank soils in Kashmir, India, at an elevation of over 3000 metres, where temperatures rarely exceed 10 °C. [10] This species can survive in arctic cryopegs consisting of super-cooled hypersaline liquid water deposits found beneath or within large masses of ice. [11] Geomyces pannorum has also been associated with Antarctic marine macroalgae and deep-sea ecosystems. [12] [13] It is one of the most common fungi isolated in these environments, which suggests that they are involved in decomposition and nutrient-cycling in cold marine ecosystems. [12] Geomyces pannorum is tolerant of up to three times the salinity of seawater. [11] [14] This fungus maintains cell and membrane function at low temperatures by elevating levels of unsaturated fats and compounds with cryoprotectant properties such as trehalose and various polyols. [11] [15] [16] The enzyme systems also retain function at low temperature. [8]
Other reported substrates include debris from a coal mine in Canada, frozen leaf litter, meat, cod, gelatin, and flour. [17] [18] The species is also known from indoor environments where it has been found growing on damp walls, floors of gymnasiums, and on paper in archives and libraries. [18] Geomyces pannorum has commonly been isolated from the hairs of burrowing mammals, [11] the feathers of petrels, skuas, and penguins, [19] and the exoskeletons of flying arthropods, [20] all of which may contribute to its dispersal.
Colonies of G. pannorum are yellow-brown in colour, and typically have a granular, powdery texture produced by microscopic, tree-like sporulating structures. [1] [21] [22] The conidia of this fungus are small, wedge-shaped with a flat base. They are smooth or slightly rough-walled, and tend to swell slightly during maturation. [2] [21] [23] Conidia develop at the tips and along the sides of branched, tree-like conidiophores. [2] The angles of conidiophore branches tend to be less than 90°. The conidia are formed in short chains of two to four arthroconidia linked together by empty intervening cells. [2] [3] [22] [24] The conidiophores of G. pannorum have verticils, which resemble branches radiating around a central, perpendicular main branch. [2] The conidiophores and vegetative hyphae of G. pannorum are hyaline. [25] Members of the genus Chrysosporium differ in having larger conidia and acutely branched conidiophores. [26] [27]
Geomyces pannorum is a slow-growing psychrophile, exhibiting growth below 0 °C [8] [28] to as low as −20 °C. [14] [29] Strains recovered from Antarctic cryopegs germinate at −2 °C two to three weeks after inoculation. [30] Grow is typically observed at 25 °C but absent at 37 °C. [2] The fatty acid composition and metabolism of this species changes in response to environmental temperature. [31] As well, cultures isolated from different places exhibit differing morphological characteristics and varying rates of glucose and lipid utilization. [15] [30] Geomyces pannorum var. vinaceous grows at 4 °C and uses lipids more readily than glucose, possibly as a means to maintain membrane fluidity under low temperature conditions by increasing the proportion of unsaturated fatty acids. [32] In contrast, G. pannorum var. pannorum grows at 25 °C and exhibits a nutritional preference for glucose. [15]
Strains of G. pannorum are halotolerant, moderately cellulolytic, and able to survive and grow in the presence of multiple environmental stressors. [12] [30] This species is generally regarded to be keratinophilic (exhibiting a proclivity to grow on shed keratin) [31] and accordingly produces keratinases. [19] [33] Sodium chloride is stimulatory to its growth on Czapek's medium (a growth medium in which sodium nitrate is the sole source of nitrogen and sucrose is source of carbon). [34] Growth has been observed in low oxygen environments. [34] Geomyces pannorum is resistant to the antifungal agent cycloheximide. [2] [3] However the growth of this species is inhibited by ultraviolet(UV)-B light. [22] [35]
Although most Geomyces species remain dormant until the introduction into their environment of new organic material, G. pannorum is unique in its ability to grow on silica gel in the absence of organic material. [36] It produces a range of extracellular hydrolases including lipase, chitinase, and urease. [11] It has been reported as a saprotroph on the colonies of other fungi including Cladosporium sphaerospermum. [37]
Geomyces pannorum is regular contaminant found in cultures of dermatological specimens of humans and domestic animals (dogs, cats, horses). [1] [2] It is also encountered in respiratory specimens from humans and animals where its presence is similarly interpreted as clinically insignificant. [22] A case of skin infection over the upper trunk and arms of a healthy, non-immunocompromised man was reported, [38] as was a case of recurrent cutaneous G. pannorum infection was reported in three brothers with ichthyosis. [39] However the several cases where Geomyces pannorum has been implicated in infection are suspected to be erroneous. [1] [22]
Geomyces pannorum produces bioactive metabolites some of which may have pharmaceutical potential. For example, pannomycin is structurally similar to a compound known to inhibit the ATPase, SecA, in the bacterial translocase pathway. [40] Additional metabolites have been isolated from G. pannorum including antimicrobial asterric acid derivatives called "geomycins" active against Aspergillus fumigatus as well as Gram-positive and Gram-negative bacteria. [41] Other metabolites have shown activity against Pseudomonas aeruginosa , Clavibacter michiganensis , Xanthomonas campestris and the causative agent of plant crown gall tumours, Agrobacterium tumefaciens . [42]
Fungal 18S rDNA fragments of G. pannorum have been recovered from glass panels of 19th century churches in Brakel, Germany, where their presence was interpreted to contribute to have degradation. [43] Minimal organic films on optical glass provide sufficient nutrition to sustain growth of this species, causing etching of the glass surface. Geomyces pannorum has been implicated in the biodegradation of buried plastics such as polyester polyurethane. [44] It is capable of degrading plasticized polyvinyl chloride (pPVC) and polyurethane resins. [44] [45] [46]
A conidium, sometimes termed an asexual chlamydospore or chlamydoconidium, is an asexual, non-motile spore of a fungus. The word conidium comes from the Ancient Greek word for dust, κόνις (kónis). They are also called mitospores due to the way they are generated through the cellular process of mitosis. They are produced exogenously. The two new haploid cells are genetically identical to the haploid parent, and can develop into new organisms if conditions are favorable, and serve in biological dispersal.
Mycoremediation is a form of bioremediation in which fungi-based remediation methods are used to decontaminate the environment. Fungi have been proven to be a cheap, effective and environmentally sound way for removing a wide array of contaminants from damaged environments or wastewater. These contaminants include heavy metals, organic pollutants, textile dyes, leather tanning chemicals and wastewater, petroleum fuels, polycyclic aromatic hydrocarbons, pharmaceuticals and personal care products, pesticides and herbicides in land, fresh water, and marine environments.
Setosphaeria rostrata is a heat tolerant fungus with an asexual reproductive form (anamorph) known as Exserohilum rostratum. This fungus is a common plant pathogen, causing leaf spots as well as crown rot and root rot in grasses. It is also found in soils and on textiles in subtropical and tropical regions. Exserohilum rostratum is one of the 35 Exserohilum species implicated uncommonly as opportunistic pathogens of humans where it is an etiologic agent of sinusitis, keratitis, skin lesions and an often fatal meningoencephalitis. Infections caused by this species are most often seen in regions with hot climates like Israel, India and the southern USA.
Geomyces is a genus of filamentous fungi in the family Myxotrichaceae. Members of the genus are widespread in distribution, especially in northern temperate regions. Known to be psychrotolerant and associated with Arctic permafrost soils, they are equally prevalent in the air of domestic dwellings, and children's sandpits. Species of Geomyces have previously been placed in the genus Chrysosporium.
Aspergillus ochraceus is a mold species in the genus Aspergillus known to produce the toxin ochratoxin A, one of the most abundant food-contaminating mycotoxins, and citrinin. It also produces the dihydroisocoumarin mellein. It is a filamentous fungus in nature and has characteristic biseriate conidiophores. Traditionally a soil fungus, has now began to adapt to varied ecological niches, like agricultural commodities, farmed animal and marine species. In humans and animals the consumption of this fungus produces chronic neurotoxic, immunosuppressive, genotoxic, carcinogenic and teratogenic effects. Its airborne spores are one of the potential causes of asthma in children and lung diseases in humans. The pig and chicken populations in the farms are the most affected by this fungus and its mycotoxins. Certain fungicides like mancozeb, copper oxychloride, and sulfur have inhibitory effects on the growth of this fungus and its mycotoxin producing capacities.
Aspergillus versicolor is a slow-growing species of filamentous fungus commonly found in damp indoor environments and on food products. It has a characteristic musty odor associated with moldy homes and is a major producer of the hepatotoxic and carcinogenic mycotoxin sterigmatocystin. Like other Aspergillus species, A. versicolor is an eye, nose, and throat irritant.
Chrysosporium keratinophilum is a mold that is closely related to the dermatophytic fungi and is mainly found in soil and the coats of wild animals to break down keratin. Chrysosporium keratinophilum is one of the more commonly occurring species of the genus Chrysosporium in nature. It is easily detected due to its characteristic "light-bulb" shape and flat base. Chrysosporium keratinophilum is most commonly found in keratin-rich, dead materials such as feathers, skin scales, hair, and hooves. Although not identified as pathogenic, it is a regular contaminant of cutaneous specimens which leads to the common misinterpretation that this fungus is pathogenic.
Emmonsia parva is a filamentous, saprotrophic fungus and one of three species within the genus Emmonsia. The fungus is most known for its causal association with the lung disease, adiaspiromycosis which occurs most commonly in small mammals but is also seen in humans. The disease was first described from rodents in Arizona, and the first human case was reported in France in 1964. Since then, the disease has been reported from Honduras, Brazil, the Czech Republic, Russia, the United States of America and Guatemala. Infections in general are quite rare, especially in humans.
Aspergillus unguis is a species of fungus in the genus Aspergillus, and the asexual state (anamorph) of Emericella unguis. Aspergillus unguis is a filamentous soil-borne fungus found on decomposing plant matter and other moist substrates including with building materials and household dust. Aspergillus unguis occurs mainly in tropical and subtropical soils but has also been isolated from various marine and aquatic habitats. The species was first isolated in 1935 by Weill and L. Gaudin. Historically, A. unguis was assigned to the A. nidulans group, a common group of soil-borne fungi due to the resemblance of its ascospores and cleistothecia to those of Emericella nidulans. Aspergillus unguis is distinctive, however, in possessing spicular hyphae. A number of synonyms have been collapsed into this species, including Sterigmatocystis unguis, Aspergillus laokiashanensis and Aspergillus mellinus.
Trichothecium roseum is a fungus in the division Ascomycota first reported in 1809. It is characterized by its flat and granular colonies which are initially white and develop to be light pink in color. This fungus reproduces asexually through the formation of conidia with no known sexual state. Trichothecium roseum is distinctive from other species of the genus Trichothecium in its characteristic zigzag patterned chained conidia. It is found in various countries worldwide and can grow in a variety of habitats ranging from leaf litter to fruit crops. Trichothecium roseum produces a wide variety of secondary metabolites including mycotoxins, such as roseotoxins and trichothecenes, which can infect and spoil a variety of fruit crops. It can act as both a secondary and opportunistic pathogen by causing pink rot on various fruits and vegetables and thus has an economical impact on the farming industry. Secondary metabolites of T. roseum, specifically Trichothecinol A, are being investigated as potential anti-metastatic drugs. Several agents including harpin, silicon oxide, and sodium silicate are potential inhibitors of T. roseum growth on fruit crops. Trichothecium roseum is mainly a plant pathogen and has yet to show a significant impact on human health.
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.
Cladosporium sphaerospermum is a radiotrophic fungus belonging to the genus Cladosporium and was described in 1886 by Albert Julius Otto Penzig from the decaying leaves and branches of Citrus. It is a dematiaceous (darkly-pigmented) fungus characterized by slow growth and largely asexual reproduction. Cladosporium sphaerospermum consists of a complex of poorly morphologically differentiated, "cryptic" species that share many physiological and ecological attributes. In older literature, all of these sibling species were classified as C. sphaerospermum despite their unique nature. Accordingly, there is confusion in older literature reports on the physiological and habitat regularities of C. sphaerospermum in the strict sense. This fungus is most phylogenetically similar to C. fusiforme. According to modern phylogenetic analyses, the previously synonymized species, Cladosporium langeroni, is a distinct species.
Paecilomyces marquandii is a soil-borne filamentous fungus distributed throughout temperate to tropical latitudes worldwide including forest, grassland, sewage sludge and strongly metal polluted area characterized by high tolerance in heavy metals. Simultaneous toxic action of zinc and alachlor result an increase in uptake of metal in this fungus but disrupts the cell membrane. Paecilomyces marquandii is known to parasitize the mushroom, Cuphophyllus virgineus, in the family, Hygrophoraceae. Paecilomyces marquandii is categorised as a biosafety risk group 1 in Canada and is not thought to be a significant pathogen of humans or animals.
Aspergillus wentii is an asexual, filamentous, endosymbiotic fungus belonging to the mold genus, Aspergillus. It is a common soil fungus with a cosmopolitan distribution, although it is primarily found in subtropical regions. Found on a variety of organic materials, A. wentii is known to colonize corn, cereals, moist grains, peanuts and other ground nut crops. It is also used in the manufacture of biodiesel from lipids and is known for its ability to produce enzymes used in the food industry.
Phialophora fastigiata is a mitosporic, saprophytic fungus commonly found in soil, and on wood, and wood-pulp. This species was initially placed in the genus Cadophora but was later transferred to the genus Phialophora based on morphological and growth characteristics. In culture, P. fastigiata produces olive-brown, velvety colonies. The fungus is recognizable microscopically due to the presence of distinctive, funnel-shaped cuffs (collarettes) encircling the tips of phialides that bear slimy conidia. The fungus is often implicated in soft-rot wood decay due to its ability to degrade lignin, cellulose and pectin. It has also been reported to cause blue staining of wood and wood pulp.
Ctenomyces serratus is a keratinophilic fungal soil saprotroph classified by the German mycologist, Michael Emil Eduard Eidam in 1880, who found it growing on an old decayed feather. Many accounts have shown that it has a global distribution, having been isolated in select soils as well as on feathers and other substrates with high keratin content. It has also been found in indoor dust of hospitals and houses in Kanpur, Northern India and as a common keratinophilic soil fungus in urban Berlin. This species has been associated with nail infections in humans as well as skin lesions and slower hair growth in guinea pigs.
Microascus manginii is a filamentous fungal species in the genus Microascus. It produces both sexual (teleomorph) and asexual (anamorph) reproductive stages known as M. manginii and Scopulariopsis candida, respectively. Several synonyms appear in the literature because of taxonomic revisions and re-isolation of the species by different researchers. M. manginii is saprotrophic and commonly inhabits soil, indoor environments and decaying plant material. It is distinguishable from closely related species by its light colored and heart-shaped ascospores used for sexual reproduction. Scopulariopsis candida has been identified as the cause of some invasive infections, often in immunocompromised hosts, but is not considered a common human pathogen. There is concern about amphotericin B resistance in S. candida.
Aspergillus giganteus is a species of fungus in the genus Aspergillus that grows as a mold. It was first described in 1901 by Wehmer, and is one of six Aspergillus species from the Clavati section of the subgenus Fumigati. Its closest taxonomic relatives are Aspergillus rhizopodus and Aspergillus longivescia.
Myriodontium keratinophilum is a fungus widespread in nature, most abundantly found in keratin-rich environments such as feathers, nails and hair. Despite its ability to colonize keratinous surfaces of human body, the species has been known to be non-pathogenic in man and is phylogentically distant to other human pathogenic species, such as anthropophilic dermatophytes. However, its occasional isolation from clinical specimens along with its keratinolytic properties suggest the possibility it may contribute to disease.
Oidiodendron cereale is a species of ascomycetes fungi in the order Helotiales. This fungus is found globally in temperate climates where average summer temperatures are below 25 °C, but there have been scattered reports from tropical and subtropical environments. It is predominantly found in soil, but little is known regarding their ecological roles in nature. However, an enzymatic study from Agriculture Canada showed that O. cereale can break down a variety of plant, fungal, and animal based substrates found in soil, which may have beneficial effects for plants. On rare occasions, this fungus is found on human skin and hair. There has been one reported case of O. cereale infection in 1969, causing Neurodermitis Nuchae.