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Neurospora

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Neurospora
Neurospora crassa
Scientific classificationEdit this classification
Domain: Eukaryota
Kingdom: Fungi
Division: Ascomycota
Class: Sordariomycetes
Order: Sordariales
Family: Sordariaceae
Genus: Neurospora
Shear&B.O.Dodge(1927)
Type species
Neurospora sitophila
Shear & B.O.Dodge (1927)
Synonyms[1]
  • GelasinosporaDowding (1933)
  • AnixiellaSaito & Minoura (1948)
  • AnixiellaSaito & Minoura ex Cain (1961)
  • ChrysoniliaArx (1981)
Oncom,made usingNeurospora intermediavar.oncomensis

Neurosporais agenusofAscomycetefungi.The genus name, meaning "nerve spore" refers to the characteristic striations on the spores that resembleaxons.

The best known species in this genus isNeurospora crassa,a commonmodel organisminbiology.Neurospora intermediavar.oncomensisis believed to be the only mold belonging toNeurosporawhich is used in food production (to makeoncom).[2]

Characteristics

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Neurosporaspecies aremoldswith broadly spreadingcolonies,with abundant production ofascomata.Ascomata are superficial or immersed,perithecialand ostiolate or cleistothecial and non-ostiolate, hairy or glabrous, dark coloured.Peridiummembranaceous,ascicylindrical, clavate or subspherical, with a persistent or evanescent wall, usually with a thickened and non-amyloid annular structure at the apex, usually 8-spored.Ascosporesbroadly fusiform, ellipsoidal, or nearly spherical, unicellular, hyaline to yellowish brown or olive-brown, becoming dark and opaque at maturity, ascospore wall with longitudinal ribs or pitted, occasionally nearly smooth, 1–2 (but rarely up to 12) germ pores disposed at the ends of the ascospores, gelatinous sheaths or appendages are absent.Anamorphsare known in only a relatively small number of species, which belong to thefungi imperfectigenusChrysonilia.The type species of the genus isNeurospora sitophilaShear.[3]

Systematics

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The former genusGelasinosporais closely related and not resolved as a distinct monophyletic group,[4]thus the former genus is nowadays included as a synonym ofNeurospora.[3]

Species

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As model organisms

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Neurosporais widely used in genetics as amodel organism(especiallyN. crassa) because it quickly reproduces, is easy to culture,[5]and can survive onminimal media(inorganicsalts,glucose, water andbiotininagar).

The first studies of sexual reproduction inNeurosporawere made by B. O. Dodge.Neurosporawas later used byGeorge Wells BeadleandEdward Lawrie Tatumin X-ray mutation experiments to discover mutants that would differ in nutritional requirements. The results of their experiments led them to theone gene-one enzyme hypothesis,in which they postulated that everyenzymewas encoded with its owngene.

Research withNeurosporais reported semi-annually at theNeurospora MeetingatAsilomar,California, coordinated by theFungal Genetics Stock Center.Mutant and wild-type strains ofNeurosporaare available from the FGSC. The FGSC also publishes theFungal Genetics Reports.

Important people inNeurosporaresearch:

Sexual reproduction

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In theheterothallicspeciesNeurospora crassa,the interaction of haploid strains of oppositemating typeis necessary for the occurrence of sexual reproduction and the production of ascospores bymeiosis.Ascospores then restore haploid individuals of either mating type. The life cycle phase is thus predominantly haploid, however, upon mating, the nuclei do not immediately fuse: karyogamy is delayed until the very onset of meiosis. The resulting mycelium is called aheterokaryonand is neither diploid nor haploid. The genusNeurosporaalso includeshomothallicspecies in which a single haploid individual carries both mating type loci and can undergo self-fertilization leading to meiosis and sexual reproduction.Neurospora africanais an example of such a species.[12][13]Additionally, some "Neurospora" species are said pseudohomothallic. They carry both mating types, but in separate nuclei in the same individual. Two haploid nuclei originating from the same meiosis are packaged into one ascospore.[14]The individual is thus permanently heterokaryotic. Examples of this mating system include "Neurospora tetrasperma" and "Neurospora tetraspora". Because heterothallic species necessarily undergo some degree of outcrossing they may benefit from a higher efficiency of selection because of higher effective recombination rates. In contrast, pseudohomothallic and homothallic species do not outcross (or rarely) and do not experience these benefits: in homothallics a reduced efficiency ofnegative selectionhas been shown.[15]However, both hetero- and pseudohomothallic species benefit from the masking of deleterious recessive alleles in the heterokaryotic phase. In addition, all species derive the benefits of meiosis that include the removal of stress-inducedDNA damagesbyhomologous recombinationalrepair, and the formation of stress-resistant ascospores.

References

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  1. ^"Synonymy:NeurosporaShear & B.O. Dodge, J. Agric. Res., Washington 34: 1025 (1927) ".Species Fungorum.Retrieved13 February2022.
  2. ^Ho, C.C. (April 1986). "Identity and characteristics ofNeurospora intermediaresponsible for oncom fermentation in Indonesia ".Food Microbiology.3(2): 115–132.doi:10.1016/S0740-0020(86)80035-1.
  3. ^abGarcia, D.; et al. (2004). "A synopsis and re-circumscription ofNeurospora(syn.Gelasinospora) based on ultrastructural and 28S rDNA sequence data ".Mycological Research.108(10): 1119–1142.doi:10.1017/s0953756204000218.PMID15535064.S2CID31673455.
  4. ^Cai, L.; et al. (2006). "Phylogenetic investigations of Sordariaceae based on multiple gene sequences and morphology".Mycological Research.110(2): 137–150.doi:10.1016/j.mycres.2005.09.014.PMID16378718.
  5. ^abDodge, B. O. (1932). "Crossing hermaphroditic races ofNeurospora".Mycologia.24(1): 7–13.doi:10.2307/3753727.JSTOR3753727.
  6. ^Zimmer, E. M., August 1946, "MUTANT STRAINS OF NEUROSPORA DEFICIENT IN PARA-AMINOBENZOIC ACID", MA Thesis, Stanford University
  7. ^Hollaender, A.,Sansome E. R.,Zimmer, E.,Demerec, M.,April 1945, "Quantitative Irradiation Experiments with Neurospora crassa. II. Ultraviolet Irradiation",American Journal of Botany 32(4):226-235 Also: "Quantitative effects of radiation on mutation production in Neurospora crassa", Records of the Genetics Society of America, Number Thirteen, 1944
  8. ^abGiles, N. H. Jr., Lederberg, E. Z., March 1948, "Induced reversions of biochemical mutants in Neurospora crassa", American Journal of Botany 35(3):150-157
  9. ^Mitchell HK, Nyc JF (January 1948)."Hydroxyanthranilic Acid as a Precursor of Nicotinic Acid in Neurospora"(PDF).Proc. Natl. Acad. Sci. U.S.A.34(1): 1–5.Bibcode:1948PNAS...34....1M.doi:10.1073/pnas.34.1.1.PMC1062899.PMID16588774.
  10. ^Mitchell MB (April 1955)."Aberrant Recombination Of Pyridoxine Mutants ofNeurospora".Proc. Natl. Acad. Sci. U.S.A.41(4): 215–20.Bibcode:1955PNAS...41..215M.doi:10.1073/pnas.41.4.215.PMC528059.PMID16589648.
  11. ^Merrow, M, Brunner M, Roenneberg T (June 1999)."Assignment of circadian function for theNeurosporaclock gene frequency "(PDF).Nature.399(6736): 584–586.Bibcode:1999Natur.399..584M.doi:10.1038/21190.hdl:11370/f3afd147-0431-46a1-9471-3df73e14d070.PMID10376598.S2CID4422762.{{cite journal}}:CS1 maint: multiple names: authors list (link)
  12. ^Glass NL, Smith ML (August 1994). "Structure and function of a mating-type gene from the homothallic species Neurospora africana".Mol. Gen. Genet.244(4): 401–9.doi:10.1007/bf00286692.PMID8078466.S2CID19747733.
  13. ^Metzenberg RL, Glass NL (February 1990). "Mating type and mating strategies in Neurospora".BioEssays.12(2): 53–9.doi:10.1002/bies.950120202.PMID2140508.S2CID10818930.
  14. ^Raju, N. B., Perkins, D. D. (1994). "Diverse programs of ascus development in pseudohomothallic species of Neurospora, Gelasinospora, and Podospora".Developmental Genetics.15(1): 104–118.doi:10.1002/dvg.1020150111.PMID8187347.{{cite journal}}:CS1 maint: multiple names: authors list (link)
  15. ^Nygren, Kristiina, Wallberg, Andreas, Samils, Nicklas, Stajich, Jason E., Townsend, Jeffrey P., Karlsson, Magnus, Johannesson, Hanna (2012). "Analyses of expressed sequence tags in Neurospora reveal rapid evolution of genes associated with the early stages of sexual reproduction in fungi".BMC Evol. Biol.12(3): 649–663.doi:10.1016/j.ympev.2011.03.023.PMID21439389.{{cite journal}}:CS1 maint: multiple names: authors list (link)
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