Pseudoplectania nigrella
Encyclopedia
Pseudoplectania nigrella, commonly known as the ebony cup, the black false plectania, or the hairy black cup, is a species of fungi in the family Sarcosomataceae
. The fruit bodies
of this saprobic fungus are small blackish cups, typically up to 2 cm (0.78740157480315 in) broad, that grow in groups on soil, often amongst pine needles and short grass near coniferous trees. Pseudoplectania nigrella has a worldwide distribution, and has been found in North America, the Caribbean, Britain, Europe, India, Madagascar, New Zealand, and Japan. The fungus produces a unique chemical compound, plectasin, that has attracted research interest for its ability to inhibit the growth of the common human pathogenic
bacterium Streptococcus pneumoniae
.
named the species Peziza nigrella in his Systema Mycologia in 1801, and it was sanctioned
under this name in Elias Magnus Fries
' Systema Mycologicum
in 1821. In 1870, German mycologist Fuckel
transferred it to his newly described genus Pseudoplectania
, and made it the type species
. The species was ulteriorly placed in Crouania by Friedrich August Hazslinszky von Hazslin
, and in Plectania
by Petter Karsten (1885), but neither placement is considered correct.
The fungus is commonly
known as the "ebony cup", the "black false plectania", or the "hairy black cup".
; it is brownish-black, with an edge that is often wavy and curved slightly inwards, and covered with fine hairs. The cups may reach up to 2 cm (0.78740157480315 in) in diameter. The hairs are long but usually closely coiled and twisted, which gives to the exterior of the cup a slightly tomentose appearance of nearly uniform thickness throughout their entire length. They are pale brown and 4–6 µm
in diameter.
The asci
are roughly cylindrical with a long stem-like base; the entire ascus is often as long as 300–325 µm and about 15 µm in diameter at the thickest point. The spores
are round, smooth, translucent (hyaline
), and have diameters of about 12–14 µm. They are filled with many small oil droplets. The paraphyses
(sterile filamentous hyphae in the hymenium) are enlarged at their tips and filled with brown colored matter, about 4 µm thick.
Pseudoplectania nigrella has a worldwide distribution, and has been found in North America, the Caribbean, Europe, India, Madagascar, New Zealand, Israel, and Japan.
s are antibiotic
s made from peptides and are typically found in animals and higher plants. Plectasin
, found in Pseudoplectania nigrella, is the first defensin to be isolated from a fungus. Plectasin has a chemical structure resembling defensins found in spiders, scorpions, dragonflies and mussels. In general, defensins have commonalities in their molecular structure, such as cysteine
s in the peptide stabilized with disulfide bond
s. In particular, defensins from P. nigrella, invertebrates, and plants and share a conformation
that has been named the CSαβ motif
. In laboratory tests, plectasin was especially active in inhibiting the growth of the common human pathogen Streptococcus pneumoniae
, including strains resistant
to conventional antibiotics. Plectasin has a low toxicity in mice, and cured them of peritonitis
and pneumonia
caused by S. pneumoniae as efficiently as vancomycin
and penicillin
, suggesting that it may have therapeutic potential. In 2010, Chinese scientists announced a method for high-level production of plectasin using an E. coli protein expression system.
Sarcosomataceae
The Sarcosomataceae are a family of fungi in the order Pezizales. According to a 2008 estimate, the family contains 10 genera and 57 species. Most species are found in temperate areas, and are typically saprobic on rotten or buried wood....
. The fruit bodies
Ascocarp
An ascocarp, or ascoma , is the fruiting body of an ascomycete fungus. It consists of very tightly interwoven hyphae and may contain millions of asci, each of which typically contains eight ascospores...
of this saprobic fungus are small blackish cups, typically up to 2 cm (0.78740157480315 in) broad, that grow in groups on soil, often amongst pine needles and short grass near coniferous trees. Pseudoplectania nigrella has a worldwide distribution, and has been found in North America, the Caribbean, Britain, Europe, India, Madagascar, New Zealand, and Japan. The fungus produces a unique chemical compound, plectasin, that has attracted research interest for its ability to inhibit the growth of the common human pathogenic
Pathogen
A pathogen gignomai "I give birth to") or infectious agent — colloquially, a germ — is a microbe or microorganism such as a virus, bacterium, prion, or fungus that causes disease in its animal or plant host...
bacterium Streptococcus pneumoniae
Streptococcus pneumoniae
Streptococcus pneumoniae, or pneumococcus, is Gram-positive, alpha-hemolytic, aerotolerant anaerobic member of the genus Streptococcus. A significant human pathogenic bacterium, S...
.
Taxonomy and naming
Christian Hendrik PersoonChristian Hendrik Persoon
Christiaan Hendrik Persoon was a mycologist who made additions to Linnaeus' mushroom taxonomy.-Early life:...
named the species Peziza nigrella in his Systema Mycologia in 1801, and it was sanctioned
Sanctioned name
In mycology, a sanctioned name is a name that was adopted in certain works of Christiaan Hendrik Persoon or Elias Magnus Fries, which are considered major points in fungal taxonomy.-Definition and effects:...
under this name in Elias Magnus Fries
Elias Magnus Fries
-External links:*, Authors of fungal names, Mushroom, the Journal of Wild Mushrooming.*...
' Systema Mycologicum
Systema Mycologicum
Systema Mycologicum is a systematic classification of fungi drawn up in 1821 by the Swedish mycologist and botanist Elias Fries. It took 11 years to complete....
in 1821. In 1870, German mycologist Fuckel
Karl Wilhelm Gottlieb Leopold Fuckel
Karl Wilhelm Gottlieb Leopold Fuckel was a German botanist who worked largely on fungi.The species epithet in the binomen Botryotinia fuckeliana, a plant pathogen and the causal agent of gray mold disease, was named by mycologist Heinrich Anton de Bary in honor of Fuckel.Formerly in nations that...
transferred it to his newly described genus Pseudoplectania
Pseudoplectania
Pseudoplectania is a genus of fungi in the family Sarcosomataceae. According to the Dictionary of the Fungi , the genus contains three or four species, found in Europe and North America.-Taxonomy:...
, and made it the type species
Type species
In biological nomenclature, a type species is both a concept and a practical system which is used in the classification and nomenclature of animals and plants. The value of a "type species" lies in the fact that it makes clear what is meant by a particular genus name. A type species is the species...
. The species was ulteriorly placed in Crouania by Friedrich August Hazslinszky von Hazslin
Friedrich August Hazslinszky von Hazslin
Frigyes Ákos Hazslinszky or in German version of his name Friedrich August Hazslinszky von Hazslin was a Hungarian mycologist and botanist. Upon completing his lyceum studies in Késmark , he studied philosophy, law, theology and chemistry, working concurrently as a teacher...
, and in Plectania
Plectania
Plectania is a genus of fungi in the Sarcosomataceae family. There are 15 species in the genus, which have a widespread distribution, especially in northern temperate areas.-External links:* at Index Fungorum...
by Petter Karsten (1885), but neither placement is considered correct.
The fungus is commonly
Common name
A common name of a taxon or organism is a name in general use within a community; it is often contrasted with the scientific name for the same organism...
known as the "ebony cup", the "black false plectania", or the "hairy black cup".
Description
The fruit bodies (technically called apothecia) typically grow in groups, or sometimes crowded closely together, with small stems or missing them entirely. Initially, the fruit bodies are closed and roughly spherical, but as they develop they expand to become cup-shaped, or almost flat. The inner surface of the cups bear the reproductive spore-bearing layer, or hymeniumHymenium
The hymenium is the tissue layer on the hymenophore of a fungal fruiting body where the cells develop into basidia or asci, which produce spores. In some species all of the cells of the hymenium develop into basidia or asci, while in others some cells develop into sterile cells called cystidia or...
; it is brownish-black, with an edge that is often wavy and curved slightly inwards, and covered with fine hairs. The cups may reach up to 2 cm (0.78740157480315 in) in diameter. The hairs are long but usually closely coiled and twisted, which gives to the exterior of the cup a slightly tomentose appearance of nearly uniform thickness throughout their entire length. They are pale brown and 4–6 µm
Micrometre
A micrometer , is by definition 1×10-6 of a meter .In plain English, it means one-millionth of a meter . Its unit symbol in the International System of Units is μm...
in diameter.
The asci
Ascus
An ascus is the sexual spore-bearing cell produced in ascomycete fungi. On average, asci normally contain eight ascospores, produced by a meiotic cell division followed, in most species, by a mitotic cell division. However, asci in some genera or species can number one , two, four, or multiples...
are roughly cylindrical with a long stem-like base; the entire ascus is often as long as 300–325 µm and about 15 µm in diameter at the thickest point. The spores
Ascospore
An ascospore is a spore contained in an ascus or that was produced inside an ascus. This kind of spore is specific to fungi classified as ascomycetes ....
are round, smooth, translucent (hyaline
Hyaline
The term hyaline denotes a substance with a glass-like appearance.-Histopathology:In histopathological medical usage, a hyaline substance appears glassy and pink after being stained with haematoxylin and eosin — usually it is an acellular, proteinaceous material...
), and have diameters of about 12–14 µm. They are filled with many small oil droplets. The paraphyses
Paraphyses
Paraphyses are part of the fertile spore-bearing layer in certain fungi. More specifically, paraphyses are sterile filamentous hyphal end cells composing part of the hymenium of Ascomycota and Basidiomycota interspersed among either the asci or basidia respectively, and not sufficiently...
(sterile filamentous hyphae in the hymenium) are enlarged at their tips and filled with brown colored matter, about 4 µm thick.
Similar species
Pseudoplectania sphagnophila resembles P. nigrella, but has a more deeply and persistently cup-shaped fruit body, a short but distinct stem, and only grows amongst sphagnum moss. Plectania melastoma has elliptical to spindle-shaped spores measuring 20–28 by 8–12 µm, while P. milleri has elliptical spores, and the margin of its cups have star-shaped points.Edibility
Pseudoplectania nigrella is considered inedible. It has no distinctive taste or odor.Habitat and distribution
This species is saprobic, and is found growing in groups on the ground or on moss-covered decaying wood, especially amongst fallen pine needles. In North America, fruit bodies appear in the spring and summer, and are fairly common; in Britain, the fungus fruits from winter to spring, and is rare. Its small size and dark color makes it easy to overlook.Pseudoplectania nigrella has a worldwide distribution, and has been found in North America, the Caribbean, Europe, India, Madagascar, New Zealand, Israel, and Japan.
Bioactive compounds
DefensinDefensin
Defensins are small cysteine-rich cationic proteins found in both vertebrates and invertebrates. They have also been reported in plants. They are, and function as, host defense peptides. They are active against bacteria, fungi and many enveloped and nonenveloped viruses. They consist of 18-45 amino...
s are antibiotic
Antibiotic
An antibacterial is a compound or substance that kills or slows down the growth of bacteria.The term is often used synonymously with the term antibiotic; today, however, with increased knowledge of the causative agents of various infectious diseases, antibiotic has come to denote a broader range of...
s made from peptides and are typically found in animals and higher plants. Plectasin
Plectasin
Plectasin is a antibiotic found by Novozymes in the Pezizalean fungus Pseudoplectania nigrella. Plectasin belongs to the antimicrobial peptide class called Defensins, which is also present in invertebrates such as flies and mussels...
, found in Pseudoplectania nigrella, is the first defensin to be isolated from a fungus. Plectasin has a chemical structure resembling defensins found in spiders, scorpions, dragonflies and mussels. In general, defensins have commonalities in their molecular structure, such as cysteine
Cysteine
Cysteine is an α-amino acid with the chemical formula HO2CCHCH2SH. It is a non-essential amino acid, which means that it is biosynthesized in humans. Its codons are UGU and UGC. The side chain on cysteine is thiol, which is polar and thus cysteine is usually classified as a hydrophilic amino acid...
s in the peptide stabilized with disulfide bond
Disulfide bond
In chemistry, a disulfide bond is a covalent bond, usually derived by the coupling of two thiol groups. The linkage is also called an SS-bond or disulfide bridge. The overall connectivity is therefore R-S-S-R. The terminology is widely used in biochemistry...
s. In particular, defensins from P. nigrella, invertebrates, and plants and share a conformation
Protein structure
Proteins are an important class of biological macromolecules present in all organisms. Proteins are polymers of amino acids. Classified by their physical size, proteins are nanoparticles . Each protein polymer – also known as a polypeptide – consists of a sequence formed from 20 possible L-α-amino...
that has been named the CSαβ motif
Structural motif
In a chain-like biological molecule, such as a protein or nucleic acid, a structural motif is a supersecondary structure, which appears also in a variety of other molecules...
. In laboratory tests, plectasin was especially active in inhibiting the growth of the common human pathogen Streptococcus pneumoniae
Streptococcus pneumoniae
Streptococcus pneumoniae, or pneumococcus, is Gram-positive, alpha-hemolytic, aerotolerant anaerobic member of the genus Streptococcus. A significant human pathogenic bacterium, S...
, including strains resistant
Antibiotic resistance
Antibiotic resistance is a type of drug resistance where a microorganism is able to survive exposure to an antibiotic. While a spontaneous or induced genetic mutation in bacteria may confer resistance to antimicrobial drugs, genes that confer resistance can be transferred between bacteria in a...
to conventional antibiotics. Plectasin has a low toxicity in mice, and cured them of peritonitis
Peritonitis
Peritonitis is an inflammation of the peritoneum, the serous membrane that lines part of the abdominal cavity and viscera. Peritonitis may be localised or generalised, and may result from infection or from a non-infectious process.-Abdominal pain and tenderness:The main manifestations of...
and pneumonia
Pneumonia
Pneumonia is an inflammatory condition of the lung—especially affecting the microscopic air sacs —associated with fever, chest symptoms, and a lack of air space on a chest X-ray. Pneumonia is typically caused by an infection but there are a number of other causes...
caused by S. pneumoniae as efficiently as vancomycin
Vancomycin
Vancomycin INN is a glycopeptide antibiotic used in the prophylaxis and treatment of infections caused by Gram-positive bacteria. It has traditionally been reserved as a drug of "last resort", used only after treatment with other antibiotics had failed, although the emergence of...
and penicillin
Penicillin
Penicillin is a group of antibiotics derived from Penicillium fungi. They include penicillin G, procaine penicillin, benzathine penicillin, and penicillin V....
, suggesting that it may have therapeutic potential. In 2010, Chinese scientists announced a method for high-level production of plectasin using an E. coli protein expression system.