Chaetomium globosum ist ein cellulosezersetzender Schimmelpilz aus der Gattung Chaetomium. Die Art ist weit verbreitet und zeigt zwei verschiedene Vorkommensschwerpunkte: Einerseits im Inneren von Blättern lebender Pflanzen (endophytisch), andererseits frei lebend auf abgestorbener pflanzlicher Biomasse aller Art, so in Böden, im Kot von Pflanzenfressern und in Totholz. Als ubiquistische Art ist er auch in Innenräumen von Gebäuden anzutreffen. Er kommt in Innenräumen nach Wasserschäden,[1] in Archiven sowie als Moderfäulepilz in Holz (besonders Holz mit hoher Feuchte) vor.[2] Chaetomium globosum ist ein verbreitetes Allergen.[3][4]
Chaetomium globosum wächst optimal bei Temperaturen zwischen 18 und 24 °C und einem pH-Wert von 7,3. Nach Kulturexperimenten besitzt er die Enzymausstattung zum Abbau einer Reihe von pflanzlichen Polysacchariden, zum Beispiel Glucose, Cellulose und Xylan. Zum Abbau von Pektin, einem wichtigen Bestandteil der Mittellamelle des Zellgewebes lebender Blätter, gibt es widersprüchliche Angaben.[5] Die Cellulase-Aktivität wird für den biotechnologischen Einsatz getestet.[6] Endophytisch ist er bei einer Vielzahl von Pflanzen nachgewiesen worden, so zahlreichen Baum- und Straucharten, wichtigen Kulturpflanzen wie Weizen, aber auch marinen Rotalgen. Er wächst hier in der extrazellulären Matrix. Nach allen bisherigen Erkenntnissen fügt der Pilz seinem Wirtsorganismus keinen Schaden zu. Es scheint im Gegenteil so zu sein, dass die Pflanze von der Anwesenheit des Pilzes profitiert, weil dessen sekundäre Metabolite ihr Schutz gegen eine Reihe pflanzenfressender Schädlinge verleihen. Die Art wird deshalb für den Einsatz in der biologischen Schädlingsbekämpfung getestet.[7] Angestrebt wird vor allem ein Einsatz gegen saugende Arten wie Blattläuse, gegen die der verbreitete Einsatz des Bt-Toxins keine Wirkung zeigt.[8]
Der Pilz bildet Mykotoxine,[1] wie z. B. Emodin, diverse Cytochalasane, das antibiotisch aktive Chaetomin[3] und Chaetomugilin.[9]
Die frei lebenden, saprotrophen und die endophytischen Stämme des Pilzes sind morphologisch, genetisch und nach ihrer Enzymausstattung miteinander verglichen worden.[5], zwischen ihnen besteht demnach kein Unterschied. Im Gegensatz zu den ebenfalls endophytischen, vor allem in Grasblättern verbreiteten Pilzen der Gattung Neotyphodium, die ebenfalls für die Resistenz gegenüber Pflanzenfressern bedeutsam sind, wird Chaetomium globosum nicht über Weitergabe mit dem Samen (vertikal), sondern durch Neuinfektion aus der Umgebung (horizontal) übertragen.[5]
Chaetomium globosum ist ein cellulosezersetzender Schimmelpilz aus der Gattung Chaetomium. Die Art ist weit verbreitet und zeigt zwei verschiedene Vorkommensschwerpunkte: Einerseits im Inneren von Blättern lebender Pflanzen (endophytisch), andererseits frei lebend auf abgestorbener pflanzlicher Biomasse aller Art, so in Böden, im Kot von Pflanzenfressern und in Totholz. Als ubiquistische Art ist er auch in Innenräumen von Gebäuden anzutreffen. Er kommt in Innenräumen nach Wasserschäden, in Archiven sowie als Moderfäulepilz in Holz (besonders Holz mit hoher Feuchte) vor. Chaetomium globosum ist ein verbreitetes Allergen.
Chaetomium globosum is a well-known mesophilic member of the mold family Chaetomiaceae. It is a saprophytic fungus that primarily resides on plants, soil, straw, and dung. Endophytic C. globosum assists in cellulose decomposition of plant cells.[1] They are found in habitats ranging from forest plants to mountain soils across various biomes.[2][3][4] C. globosum colonies can also be found indoors and on wooden products.[5][6]
Chaetomium globosum are human allergens and opportunistic agents of ungual mycosis and neurological infections. However such illnesses occur at low rates.[6][7]
Like most Chaetomium species, C. globosum decomposes plant cells using hyphal cellulase activity.[8] Even though they are known to cause soft rot rather than brown rot, C. globosum plant decomposition leaves behind lignin residues.[8] They can decay a variety of wood types such as aspen and pine and even change the colour of paper and books.[8] The cellulase activity of C. globosum functions best at temperatures ranging from 25-32 degrees Celsius and is stimulated by nitrogen and biotin. Cellulase is inhibited by ethyl malonate.[4]
Like many fungal species, C. globosum obtains their energy from carbon sources such as glucose, mannitol and fructose.[4] Fructose is usually digested outside the hyphae using fructokinase activity, whereas glucose enters the cell undigested for cellular metabolism. Even though glucose is the most preferred carbon source, C. globosum mycelium growth occurs at a higher rate when treated with acetate rather than glucose. Carbohydrates can also be stored within the fungus as glycogen and trehalose energy reserves.[4]
Homothallic C.globosum sexual sporulation produces flat lemon-shaped ascospores within clavate ascomata. The appearance of C.globosum fruiting bodies are similar to the pycnidia of the genus Pyrenochaeta.[9] The ascomata optimally fructify at temperatures ranging from 18-20 degrees Celsius and develop asci with 8 ascospores each.[10] Additional conditions such as neutral pH, mild levels of carbon dioxide, the presence of calcium ions, and soluble sugar media also assist in the development of fruiting bodies.[4] The soluble sugar media consists of glucose, maltose, sucrose, and cellulose.
Sporulation preferably occurs in the dark and at high temperatures around 26 degrees Celsius.[4] The presence of cellulose is also crucial for sporulation. The smooth ascospores are initially red in colour, however upon maturation both the fruiting body and ascospores are dematiaceous.[3][11] Dark perithecia with unbranched radiating hairs can be seen as well.[10] C. globosum perithecia are similar in appearance to the related species of Chaetomium elatum, however the latter is distinguished by its branched perithecial hairs.[11] C. globosum ascospores can withstand temperatures slightly higher than optimal, however temperatures exceeding their thermal death point of 55 degrees Celsius, is lethal for the spores.[1]
Ascospores germinate by releasing globose vesicles from their apical germ pores which later develop into germ tubes. The germ tubes then grow into hyaline septate hyphae.[10] Filamentous irregular hyphal growth allows the colony to spread and develop into pale aerial mycelium.[11][12] Hyphal growth increases the diameter of the fungal colony which is often a parameter for fungal growth.[1] According to Domsch et al., C. globosum species are fast growing colonies and can grow up to 5.5 cm in diameter over a period of 10 days.[4] The germination of ascospores can be inhibited by tannin and species of Streptomyces. On the other hand, germination is stimulated by glucose. Glucose deprivation can result in reduced levels of germination.[1][4]
Chaetomium globosum can be commonly found contaminating damp buildings throughout North America and Europe.[13] Approximately 10-30% of North American homes contain moisture induced molds.[6] This poses a health concern due to the allergic nature of these fungi.[8] Both the C. globosum hyphae and the spores contain antigens such as Chg45, to induce IgE and IgG antibody production in allergic individuals. Although the IgE upsurge is transient, increased IgG levels persist in the serum.[6] This can lead to non-atopic asthma, sinusitis, and respiratory illnesses in the residents of contaminated buildings.[6][13] Such allergic onsets can be prevented with the use of potassium chlorate in building materials. Chlorate, toxic to many fungal strains, disrupts nitrate reduction in fungi by using fungal nitrate reductase to produce the toxic chlorite. Although it is unclear as to whether C. globosum contains nitrate reductase, chlorate is still a well known C. globosum toxin. However, even though chlorate suppresses perithecia formation, it does not affect hyphal growth nor sporulation.[8]
Chaetomium globosum colonies are potential allergens, and when residing on damp buildings, they are usually the casual agents of poor indoor air quality.[8][12] Colonies can be detected on wet building wood and also on tiles. Even though spores are usually not detected in the air, inhalation can trigger allergic response and respiratory illnesses.[8][14][13]
Although C. globosum are saprophytes, they can cause opportunistic human onychomycosis and cutaneous infections. Such non-dermatophytic species are responsible for a small percentage of onychomycosis cases.[12] Nonetheless, such pathology is rare in humans. The first well known case of C. globosum onychomycosis appeared in Korea where the patient developed hyperkeratosis of the nails. The disease symptoms were cured with antifungal terbinafine and amorolfine treatment.[7] Amphotericin B is ineffective towards pathogenic species of the Chaetomium genus.[15]
Cerebral and pulmonary infections due to Chaetomium species are not uncommon. They are known to cause superficial mycoses in immunocompromised patients.[12] C. globosum can induce petechia and skin lesions, as well as phaeohyphomycosis and brain abscess. The latter diseases are very rare.[15] In one case, an immunocompromised renal transplant patient developed fatal brain abscess due to a C. globosum infection. It was unclear as to how the strain disseminated to the brain.[16] To identify the pathogen, infected tissue was treated with KOH. The resultant displayed septate dark hyphae, characteristic of C. globosum.[15]
Chaetomium globosum produce emodins, chrysophanols, chaetoglobosins A, B, C D, E and F, as well as chetomins, and the azaphilones, chaetoviridins. Chetomins induce mammalian and gram positive bacterial toxicity.[4][17] This allows plants infected with C.globosum to resist bacterial diseases. The cytochalasin mycotoxins, chaetoglobosins A and C, disrupt cellular division and movement in mammalian cells. These cytochalasins bind to actin and affect actin polymerization. In fact, chaetoglobosin A is highly toxic in animal cells, even at minimal doses.[14]
The mycotoxins benefit C. globosum colonies by assisting their growth. This usually occurs at neutral pH when the mycotoxins are produced at optimal levels.[7][14]
Mycotoxic chaetoviridins, are known to suppress tumor formation in mice treated with C. globosum.[18] Their cytotoxic activity disrupts cancer cells.[17][19] Understanding the role of such mycotoxins could lead to novel drug applications.[18]
Chaetomium globosum are endophytic to many plants. Their asymptomatic colonization supports plant tolerance to metal toxicity.[20] Heavy metals such as copper, suppress plant growth and disrupt metabolic processes, e.g. photosynthesis. When maize plants were treated with C. globosum, they expressed less growth inhibition and increased biomass.[20] C. globosum is also known to reside in Ginkgo biloba plants.[17] Such plants use this endophytic fungus to suppress bacterial pathogens. In fact, ascospore inoculation reduces bacterial disease symptoms such as wilting, apple scabs, and seed blight in treated plants.[21] Enhancing plant stress tolerance and microbial defense, renders C. globosum application beneficial for agricultural use.[20]
Chaetomium globosum is a well-known mesophilic member of the mold family Chaetomiaceae. It is a saprophytic fungus that primarily resides on plants, soil, straw, and dung. Endophytic C. globosum assists in cellulose decomposition of plant cells. They are found in habitats ranging from forest plants to mountain soils across various biomes. C. globosum colonies can also be found indoors and on wooden products.
Chaetomium globosum are human allergens and opportunistic agents of ungual mycosis and neurological infections. However such illnesses occur at low rates.
Chaetomium globosum est une espèce de champignons lignivores de l'ordre des Sordariales qui cause la pourriture molle.
Les périthèces renferment des asques octosporés (ou quadrasporés) et souvent des paraphyses qui lui donnent un aspect chevelu. Les ascospores sont sombres et monocellulaires.
Chaetomium globosum est une espèce de champignons lignivores de l'ordre des Sordariales qui cause la pourriture molle.
Chaetomium globosum è un fungo Ascomicete. Provoca una forma di carie del legno detta "carie soffice" o anche "carie molle".
Chaetomium globosum je grzib[12], co go ôpisoł Kunze 1817. Chaetomium globosum nŏleży do zorty Chaetomium i familije Chaetomiaceae.[13][14][15]
Chaetomium globosum je grzib, co go ôpisoł Kunze 1817. Chaetomium globosum nŏleży do zorty Chaetomium i familije Chaetomiaceae.
Chaetomium globosum Kunze, 1817
Хето́мий шарови́дный (лат. Chaetómium globósum) — вид грибов-аскомицетов, относящийся к роду Хетомий (Chaetomium) семейства Хетомиевые (Chaetomiaceae). Типовой вид рода.
Колонии на овсяном агаре (OA) быстро-растущие, на 7-е сутки свыше 7 см в диаметре, сначала с необильным белым или оливково-бежевым воздушным мицелием, затем лимонно-зелёные, жёлтые, зеленовато-оливковые, серо-оливковые, тускло-зелёные при густых скоплениях плодовых тел. Экссудат жёлто-коричневый, абрикосово-жёлтый, оливковый, оливково-серый, охристый, зеленовато-оливковый. Реверс колоний абрикосово-жёлтый, оранжевый, серо-оливковый, тёмно-кирпично-красный.
На агаре с солодовым экстрактом (MEA) колонии также быстро-растущие, медово-жёлтые, оливково-бежевые, малахитово-зелёные, тускло-зелёные, с хлопчатым воздешным мицелием. Реверс жёлто-бурый, оранжевый, алый, ржаво-коричневый.
Плодовые тела — перитеции зеленовато-оливковых, оливково-серых, тускло-зелёных оттенков в отражённом свете, шаровидные или яйцевидные, 140—270 × 100—240 мкм. Стенки плодовых тел коричневые, покрыты длинными тёмными щетинками, нередко в основании серно-жёлтыми. Верхушечные шетинки извитые, изогнутые или прямые, коричневые, мелкобородавчатые, в основании 2—5 мкм толщиной. Боковые щетинки коричневые, извилистые. Аски веретеновидные или булавовидные, с 8 спорами, разделённые на стерильную ножку 10—48 мкм длиной и споросодержащую часть 19—38 × 12—17 мкм. Аскоспоры лимоновидные, уплощённые, коричневые в зрелости, 8,5—11 × 7—9,5 × 5,5—7 мкм.
Анаморфная стадия не известна.
Широко распространённый вид, часто встречающийся в почве, на гниющих растительных остатках, в том числе на древесине, в помещениях.
Chaetomium globosum Kunze, Mykol. Hefte 1: 16 (1817) — Fr., Syst. Mycol. 3: 255 (1829).
Хето́мий шарови́дный (лат. Chaetómium globósum) — вид грибов-аскомицетов, относящийся к роду Хетомий (Chaetomium) семейства Хетомиевые (Chaetomiaceae). Типовой вид рода.
