Editing Candida albicans (section)

===Yeast-to-hypha switching===

Although often referred to as '''dimorphic''', ''C. albicans'' is, in fact, [[polyphenism|polyphenic]] (often also referred to as [[pleomorphism (microbiology)|pleomorphic]]).<ref>{{cite journal | vauthors = Staniszewska M, Bondaryk M, Siennicka K, Kurzatkowski W | title = Ultrastructure of Candida albicans pleomorphic forms: phase-contrast microscopy, scanning and transmission electron microscopy | journal = Polish Journal of Microbiology | volume = 61 | issue = 2 | pages = 129–135 | year = 2012 | pmid = 23163212 | doi = 10.33073/pjm-2012-016 | doi-access = free }}</ref> When cultured in standard yeast laboratory medium, ''C. albicans'' grows as ovoid "yeast" cells. However, mild environmental changes in temperature, CO<sub>2</sub>, nutrients and pH can result in a morphological shift to filamentous growth.<ref>{{cite journal | vauthors = Si H, Hernday AD, Hirakawa MP, Johnson AD, Bennett RJ | title = Candida albicans white and opaque cells undergo distinct programs of filamentous growth | journal = PLOS Pathogens | volume = 9 | issue = 3 | pages = e1003210 | date = March 2013 | pmid = 23505370 | pmc = 3591317 | doi = 10.1371/journal.ppat.1003210 | doi-access = free }}</ref><ref>{{cite journal | vauthors = Sudbery PE | title = Growth of Candida albicans hyphae | journal = Nature Reviews. Microbiology | volume = 9 | issue = 10 | pages = 737–748 | date = August 2011 | pmid = 21844880 | doi = 10.1038/nrmicro2636 | s2cid = 205498076 }} See [https://www.nature.com/articles/nrmicro2636#figure-title figure 2] {{Webarchive|url=https://web.archive.org/web/20181215142754/https://www.nature.com/articles/nrmicro2636#figure-title |date=2018-12-15 }}.</ref> Filamentous cells share many similarities with yeast cells. Both cell types seem to play a specific, distinctive role in the survival and pathogenicity of ''C. albicans''. Yeast cells seem to be better suited for the dissemination in the bloodstream while hyphal cells have been proposed as a virulence factor. Hyphal cells are invasive and speculated to be important for tissue penetration, colonization of organs and surviving plus escaping macrophages.<ref>{{cite journal | vauthors = Sudbery P, Gow N, Berman J | title = The distinct morphogenic states of Candida albicans | journal = Trends in Microbiology | volume = 12 | issue = 7 | pages = 317–324 | date = July 2004 | pmid = 15223059 | doi = 10.1016/j.tim.2004.05.008 }}</ref><ref>{{cite journal | vauthors = Jiménez-López C, Lorenz MC | title = Fungal immune evasion in a model host-pathogen interaction: Candida albicans versus macrophages | journal = PLOS Pathogens | volume = 9 | issue = 11 | pages = e1003741 | year = 2013 | pmid = 24278014 | pmc = 3836912 | doi = 10.1371/journal.ppat.1003741 | doi-access = free }}</ref><ref>{{cite journal | vauthors = Berman J, Sudbery PE | title = Candida Albicans: a molecular revolution built on lessons from budding yeast | journal = Nature Reviews. Genetics | volume = 3 | issue = 12 | pages = 918–930 | date = December 2002 | pmid = 12459722 | doi = 10.1038/nrg948 | s2cid = 29341377 }}</ref> The transition from yeast to hyphal cells is termed to be one of the key factors in the virulence of ''C. albicans''; however, it is not deemed necessary.<ref>{{cite journal | vauthors = Shareck J, Belhumeur P | title = Modulation of morphogenesis in Candida albicans by various small molecules | journal = Eukaryotic Cell | volume = 10 | issue = 8 | pages = 1004–1012 | date = August 2011 | pmid = 21642508 | pmc = 3165445 | doi = 10.1128/EC.05030-11 }}</ref> When ''C. albicans'' cells are grown in a medium that mimics the physiological environment of a human host, they grow as filamentous cells (both true hyphae and pseudohyphae). ''C. albicans'' can also form [[chlamydospore]]s, the function of which remains unknown, but it is speculated they play a role in surviving harsh environments as they are most often formed under unfavorable conditions.<ref name="Staib2007">{{cite journal | vauthors = Staib P, Morschhäuser J | title = Chlamydospore formation in Candida albicans and Candida dubliniensis--an enigmatic developmental programme | journal = Mycoses | volume = 50 | issue = 1 | pages = 1–12 | date = January 2007 | pmid = 17302741 | doi = 10.1111/j.1439-0507.2006.01308.x | s2cid = 7387908 }}</ref>

The cAMP-PKA signaling cascade is crucial for the morphogenesis and an important transcriptional regulator for the switch from yeast like cells to filamentous cells is EFG1.<ref>{{cite journal | vauthors = Sohn K, Urban C, Brunner H, Rupp S | title = EFG1 is a major regulator of cell wall dynamics in Candida albicans as revealed by DNA microarrays | journal = Molecular Microbiology | volume = 47 | issue = 1 | pages = 89–102 | date = January 2003 | pmid = 12492856 | doi = 10.1046/j.1365-2958.2003.03300.x | s2cid = 23743789 | doi-access = free }}</ref><ref>{{cite journal | vauthors = Shapiro RS, Robbins N, Cowen LE | title = Regulatory circuitry governing fungal development, drug resistance, and disease | journal = Microbiology and Molecular Biology Reviews | volume = 75 | issue = 2 | pages = 213–267 | date = June 2011 | pmid = 21646428 | pmc = 3122626 | doi = 10.1128/MMBR.00045-10 }}</ref>
[[File:Whiteopaquecandida.jpg|Round, white-phase and elongated, opaque-phase ''Candida albicans'' cells: the scale bar is 5 μm|thumb]]
[[File:Whiteopaqueregulation.jpg|thumb|In this model of the genetic network regulating the white-opaque switch, the white and gold boxes represent genes enriched in the white and opaque states, respectively. The blue lines represent relationships based on genetic epistasis. Red lines represent Wor1 control of each gene, based on Wor1 enrichment in chromatin immunoprecipitation experiments. Activation (arrowhead) and repression (bar) are inferred based on white- and opaque-state expression of each gene.]]