Actinomucor elegans | |
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Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Fungi |
Division: | Mucoromycota |
Class: | Mucoromycetes |
Order: | Mucorales |
Family: | Mucoraceae |
Genus: | Actinomucor |
Species: | A. elegans |
Binomial name | |
Actinomucor elegans | |
Synonyms | |
Actinomucor elegans meitauza(Y.K. Shih) R.Y. Zheng & X.Y. Liu 2005 Contents |
Actinomucor elegans was originally described by Schostakowitsch in Siberia in 1898 and reevaluated by Benjamin and Hesseltine in 1957. [1] Commonly found in soil [2] and used for the commercial production of tofu and other products made by soy fermentation. Its major identifying features are its spine-like projections on the sporangiophore [1] and its ribbon-like hyphal structure when found in the tissue of a host. [2]
The Actinomucor genus has many shared similarities with the genus Mucor. The specific differences lie in the branched hyphae of Actinomucor that give rise to rhizoids and sporangiophores. In terms of its differences from other similar genera, the limited growth of hyphae and the variation in the structure of columella and sporangiophores give Actinomucor multiple differentiable characteristics to other genera. [1]
Mycelial growths of A. elegans have a high number of rhizoids branching out of each individual growth. On portions of growth that lack opposite rhizoids, aseptate hyphal growths with clear sporangiophores that are found with extreme variability in length and width. These hyphal structures grow out in whorled structures with growth terminating in the development of sporangiophores. [1] [2] [3] [4] [5] The sporangia are oval to spherical in shape and 17–50 μm in diameter. The walls of the sporangia possess prominent spine-like projections, which is a major identifier of this specific fungus. [1] The coloration of colonies of this fungi is white to cream-colored with an abundance of aerial mycelium. Cultures allowed to develop for a longer period of time (greater than 48 hours) change to become yellowish to buff color with increased aerial mycelium development and tight interweaving of these mycelia. [1] When this fungus is found in a human host the structure is explained to be similar to the genus Mucor, but with unique ribbon-like hyphal structures and irregular branching and thickness. [2] [4] [5]
Identified as an arising human fungal pathogen the recorded instances of mucormycosis due to A. elegans are limited to four cases. The invasion mechanisms found for A. elegans are through spore inhalation [3] or entry from ruptures in the skin. [5] This pathogen is highly-deadly when found in an immunocompromised individual, [4] and can develop into a serious infection for immunocompetent individuals as well. [3] Immunocompromised patients are affected worse by infection due to their immune system being unable to stop the germination of fungal spores resulting in there being no mechanism to slow the colonization once this pathogen is introduced. [4] In all cases involving immunocompromised individuals, the relatively large visible location of necrosis seemed to be the first indicator of an invasion. [1] [2] [3] [5] It is thought that these necrotic areas are indicative of the place on the body in which inoculation occurred. [2] A. elegans as a pathogen is categorized as a mucormycosis-causing fungus, and because of this, the current leading treatment for this type of pathogen is the removal of necrotic tissue in an effort to remove the fungal elements from the body. The severity of infection from A. elegans is due to its propensity for invasion of the vascular system and hematogenous dispersion ultimately leading to necrosis of tissue. To limit the suffering, discomfort, or expiration of a patient infected with this pathogen an early suspicion of this specific fungi needs to be established. Early identification is important as it limits the time for the fungi to colonize the host before doctors can gather infected tissue to isolate and culture the fungi to confirm its presence in the patient. Because of this pathogen's relative rarity, the time required to correctly identify the pathogen is usually not rapid enough resulting in high mortality rates of individuals infected. [5]
Mold fermentation in the production of tofu utilizes A. elegans. Through fermentation, A. elegans breaks down large macromolecules and converts them into simple fatty acids, amino acids, or sugars resulting in increased digestibility for humans. Ultimately increasing the functional and nutritional properties of tofu. [6]
Another use of A. elegans is for the fermentation processing of sufu pehtze. A. elegans is specifically proficient for the production because it possesses important enzymes for the fermentation process and results in nutritional improvements of the food. Specific enzymes that add marketable aspects to this product include glutaminase which increases palatability, and α-galactosidase [7] which reduces flatulence in people consuming the product. [8]
Actinomucor elegans is utilized for its debittering ability as well. Protein hydrolysates, such as whey and casein protein mixes all utilize proteolytic enzyme treatment to achieve heightened nutritional value, but paired with these nutritional improvements commonly comes a bitter taste. The bitter taste results from the amount and structure of hydrophobic amino acids formed in peptides. When paired with alcalase, A. elegans results in increased hydrolysis of amino acids in protein hydrolysates. Specifically, this hydrolysis occurs by A. elegans acting as an exopeptidase increasing the rate of hydrolysis resulting in a decrease of bitterness. [9]
To combat the white pollution caused by worldwide plastic waste many biodegradable products are now made out of polylactic acids (PLA) or polybutylene adipate-co-terephthalate (PBAT). Lipases secreted by A. elegans were found to be the second most proficient at expediting the full breakdown of these compounds. When a coculture of the most proficient dissolver of these compounds Pseudomonas mendocina and the second-most proficient A. elegans it resulted in a substantially higher degradation rate than either fungus could achieve individually. In the observed physical structure of this relationship, it was found that P. mendocina was attached to the mycelia of A. elegans. This synergy resulted in a higher degradation rate because A. elegans possesses a large hyphal network resulting in larger colonization of the molecule, which increased the number of colonization sites for P. mendocina resulting in the superior degrading of the molecule. From a biochemical standpoint, the degradation occurred because the lipases of A. elegans and the proteases of P. mendocina catalyzed the ester bonds of the PLA/PBAT molecules. This finding shows that there is an efficient added degradation mechanism available to be employed if products formed out of PBAT/PLA become more widespread lowering the chances for waste buildup and decreasing the harmful effect of plastics in the environment by having the ability for its full degradation to be done quickly. [10]
A hypha is a long, branching, filamentous structure of a fungus, oomycete, or actinobacterium. In most fungi, hyphae are the main mode of vegetative growth, and are collectively called a mycelium.
Zygomycosis is the broadest term to refer to infections caused by bread mold fungi of the zygomycota phylum. However, because zygomycota has been identified as polyphyletic, and is not included in modern fungal classification systems, the diseases that zygomycosis can refer to are better called by their specific names: mucormycosis, phycomycosis and basidiobolomycosis. These rare yet serious and potentially life-threatening fungal infections usually affect the face or oropharyngeal cavity. Zygomycosis type infections are most often caused by common fungi found in soil and decaying vegetation. While most individuals are exposed to the fungi on a regular basis, those with immune disorders (immunocompromised) are more prone to fungal infection. These types of infections are also common after natural disasters, such as tornadoes or earthquakes, where people have open wounds that have become filled with soil or vegetative matter.
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 tobacco. They are multicellular. Some Rhizopus species are opportunistic human pathogens that often cause fatal disease called mucormycosis. This widespread genus includes at least eight species.
The Mucorales is the largest and best-studied order of zygomycete fungi. Members of this order are sometimes called pin molds. The term mucormycosis is now preferred for infections caused by molds belonging to the order Mucorales.
Rhizopus arrhizus is a fungus of the family Mucoraceae, characterized by sporangiophores that arise from nodes at the point where the rhizoids are formed and by a hemispherical columella. It is the most common cause of mucormycosis in humans and occasionally infects other animals.
Mortierella species are soil fungi belonging to the order Mortierellales within the subphylum Mortierellomycotina. The widespread genus contains about 85 species.
Apophysomyces is a genus of filamentous fungi that are commonly found in soil and decaying vegetation. Species normally grow in tropical to subtropical regions.
Aspergillus terreus, also known as Aspergillus terrestris, is a fungus (mold) found worldwide in soil. Although thought to be strictly asexual until recently, A. terreus is now known to be capable of sexual reproduction. This saprotrophic fungus is prevalent in warmer climates such as tropical and subtropical regions. Aside from being located in soil, A. terreus has also been found in habitats such as decomposing vegetation and dust. A. terreus is commonly used in industry to produce important organic acids, such as itaconic acid and cis-aconitic acid, as well as enzymes, like xylanase. It was also the initial source for the drug mevinolin (lovastatin), a drug for lowering serum cholesterol.
Mucor mucedo, commonly known as the common pinmould, is a fungal plant pathogen and member of the phylum Mucoromycota and the genus Mucor. Commonly found on soil, dung, water, plants and moist foods, Mucor mucedo is a saprotrophic fungus found world-wide with 85 known strains. It is often mistaken for Rhizopus rots on fruits due to similar mould growth shape and colour. Contrastingly, however, Mucor mucedo is found to grow on a wide range of stored grains and plants, including cucumber and tomato. Discovered in Italy in 1729 by P.A. Micheli and later noted by Carl Linnaeus in 1753 in the Species Plantarum, Mucor mucedo was originally classified as Mucor vulgaris by Micheli but later classified synonymous under name Mucor mucedo. The species was redescribed as Ascophora mucedo by H.J. Tode in 1790 but this type resided in a stoloniferous habitat and was later made the type of new genus Rhizopus.
Mucor racemosus is a rapidly growing, weedy mould belonging to the division Mucoromycota. It is one of the earliest fungi to be grown in pure culture and was first isolated in 1886. It has a worldwide distribution and colonizes many habitats such as vegetational products, soil and houses. The fungus is mostly known for its ability to exhibit both filamentous and yeast-like morphologies, often referred to as dimorphism. Stark differences are seen in both forms and conditions of the environment heavily affect the phases of the M. racemosus. Like many fungi, it also reproduces both sexually and asexually. The dimorphic capacity of this species has been proposed as an important factor in its pathogenicity and has enhanced the industrial importance. This species is considered an opportunistic pathogen, generally limited to immunocompromised individuals. It also been associated with allergy and inflammations of facial sinuses. Its association with allergy has made it a common fungus used in allergen medical testing. Industrial use of the fungus is in the production of enzymes and the manufacture of certain dairy foods.
A fungus is any member of the group of eukaryotic organisms that includes microorganisms such as yeasts and molds, as well as the more familiar mushrooms. These organisms are classified as one of the traditional eukaryotic kingdoms, along with Animalia, Plantae and either Protista or Protozoa and Chromista.
Saksenaea vasiformis is an infectious fungus associated with cutaneous or subcutaneous lesions following trauma. It causes opportunistic infections as the entry of the fungus is through open spaces of cutaneous barrier ranging in severity from mild to severe or fatal. It lives in soils worldwide, but is considered as a rare human pathogen since only 38 cases were reported as of 2012. Saksenaea vasiformis usually fails to sporulate on the routine culture media, creating a challenge for early diagnosis, which is essential for a good prognosis. Infections are usually treated using a combination of amphotericin B and surgery. Saksenaea vasiformis is one of the few fungi known to cause necrotizing fasciitis or "flesh-eating disease".
Apophysomyces variabilis is an emerging fungal pathogen that can cause serious and sometimes fatal infection in humans. This fungus is a soil-dwelling saprobe with tropical to subtropical distribution. It is a zygomycete that causes mucormycosis, an infection in humans brought about by fungi in the order Mucorales. Infectious cases have been reported globally in locations including the Americas, Southeast Asia, India, and Australia. Apophysomyces variabilis infections are not transmissible from person to person.
Lichtheimia corymbifera is a thermophilic fungus in the phylum Zygomycota. It normally lives as a saprotrophic mold, but can also be an opportunistic pathogen known to cause pulmonary, CNS, rhinocerebral, or cutaneous infections in animals and humans with impaired immunity.
Mucor plumbeus is a fungus in the family Mucoraceae that is very common, abundant and distributed worldwide. Mucor plumbeus is not known to be a plant or animal pathogen; however it is able to elicit an immune response in humans by activating the complement system. This species is commonly found in various types of soils over a range of pH, although alkaline soils seem more conducive to its growth. It is also known from the roots of wheat, oat and barley. In addition, M. plumbeus is a common fungal contaminant of indoor built environments. This species shares many similarities with M. racemosus, another fungus that belongs to the family Mucoraceae which is known to cause mucormycosis. Mucor plumbeus is a common spoilage agent of cheese, apples, apple cider and yogurt.
Cunninghamella bertholletiae is a species of zygomycetous fungi in the order Mucorales. It is found globally, with increased prevalence in Mediterranean and subtropical climates. It typically grows as a saprotroph and is found in a wide variety of substrates, including soil, fruits, vegetables, nuts, crops, and human and animal waste. Although infections are still rare, C. betholletiae is emerging as an opportunistic human pathogen, predominantly in immunocompromised people, leukemia patients, and people with uncontrolled diabetes. Cunninghamella bertholletiae infections are often highly invasive, and can be more difficult to treat with antifungal drugs than infections with other species of the Mucorales, making prompt and accurate recognition and diagnosis of mycoses caused by this fungus an important medical concern.
Rhizopus oryzae is a filamentous heterothallic microfungus that occurs as a saprotroph in soil, dung, and rotting vegetation. This species is very similar to Rhizopus stolonifer, but it can be distinguished by its smaller sporangia and air-dispersed sporangiospores. It differs from R. oligosporus and R. microsporus by its larger columellae and sporangiospores. The many strains of R. oryzae produce a wide range of enzymes such as carbohydrate digesting enzymes and polymers along with a number of organic acids, ethanol and esters giving it useful properties within the food industries, bio-diesel production, and pharmaceutical industries. It is also an opportunistic pathogen of humans causing mucormycosis.
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.
Arthrobotrys oligospora was discovered in Europe in 1850 by Georg Fresenius. A. oligospora is the model organism for interactions between fungi and nematodes. It is the most common nematode-capturing fungus, and most widespread nematode-trapping fungus in nature. It was the first species of fungi documented to actively capture nematodes.
Lichtheimia ramosa is a saprotrophic zygomycete, typically found in soil or dead plant material. It is a thermotolerant fungus that has also been known to act as an opportunistic pathogen–infecting both humans and animals.