Editing Cyanobacteria (section)

=== Cellular death ===
[[File:Toxins-11-00706-g001.png|thumb|The hypothetical conceptual model coupling programmed cell death (PCD) and the role of microcystins (MCs) in Microcystis. (1) The extracellular stressor (e.g., ultraviolet radiation) acts on the cell. (2) Intracellular oxidative stress increases; the intracellular reactive oxygen species (ROS) content exceeds the antioxidative capacity of the cell (mediated mostly by an enzymatic system involving a superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPX)) and causes molecular damage. (3) The damage further activates the caspase-like activity, and apoptosis-like death is initiated. Simultaneously, intracellular MCs begin to be released into the extracellular environment. (4) The extracellular MCs have been significantly released from dead Microcystis cells. (5) They act on the remaining Microcystis cells, and exert extracellular roles, for example, extracellular MCs can increase the production of extracellular polysaccharides (EPS) that are involved in colony formation. Eventually, the colonial form improves the survival of the remaining cells under stressful conditions.<ref name="Programmed Cell Death-Like and Acco">{{cite journal | vauthors = Hu C, Rzymski P | title = Programmed Cell Death-Like and Accompanying Release of Microcystin in Freshwater Bloom-Forming Cyanobacterium ''Microcystis'': From Identification to Ecological Relevance | journal = Toxins | volume = 11 | issue = 12 | pages = 706 | date = December 2019 | pmid = 31817272 | pmc = 6950475 | doi = 10.3390/toxins11120706 | doi-access = free }}</ref>]]
One of the most critical processes determining cyanobacterial eco-physiology is [[cellular death]]. Evidence supports the existence of controlled cellular demise in cyanobacteria, and various forms of cell death have been described as a response to biotic and abiotic stresses. However, cell death research in cyanobacteria is a relatively young field and understanding of the underlying mechanisms and molecular machinery underpinning this fundamental process remains largely elusive.<ref name=Aguilera2021 /> However, reports on cell death of marine and freshwater cyanobacteria indicate this process has major implications for the ecology of microbial communities/<ref name="Agustí2004">{{cite journal | vauthors = Agustí S | title = Viability and niche segregation of Prochlorococcus and Synechococcus cells across the Central Atlantic Ocean. | journal = Aquatic Microbial Ecology | date = June 2004 | volume = 36 | issue = 1 | pages = 53–59 | doi = 10.3354/ame036053 | doi-access = free | hdl = 10261/86957 | hdl-access = free }}</ref><ref name="Agustí2006">{{cite journal |doi=10.1111/j.1365-2427.2006.01584.x |title=Cell death in lake phytoplankton communities |year=2006 | vauthors = Agusti S, Alou EV, Hoyer MV, Frazer TK, Canfield DE |author4-link=Thomas K. Frazer |journal=[[Freshwater Biology]] |volume=51 |issue=8 |pages=1496–1506|bibcode=2006FrBio..51.1496A }}</ref><ref name=Franklin2006>{{cite journal |doi=10.1080/09670260500505433 |title=What is the role and nature of programmed cell death in phytoplankton ecology? |year=2006 | vauthors = Franklin DJ, Brussaard CP, Berges JA |journal=European Journal of Phycology |volume=41 |issue=1 |pages=1–14 |bibcode=2006EJPhy..41....1F |doi-access=free}}</ref><ref name=Sigee2007>{{cite journal |doi=10.2216/06-69.1 |title=Patterns of cell death in freshwater colonial cyanobacteria during the late summer bloom |year=2007 | vauthors = Sigee DC, Selwyn A, Gallois P, Dean AP |journal=[[Phycologia]] |volume=46 |issue=3 |pages=284–292 |bibcode=2007Phyco..46..284S }}</ref> Different forms of cell demise have been observed in cyanobacteria under several stressful conditions,<ref name=BermanFrank2004>{{cite journal |doi=10.4319/lo.2004.49.4.0997 |title=The demise of the marine cyanobacterium, Trichodesmium SPP., via an autocatalyzed cell death pathway |year=2004 | vauthors = Berman-Frank I, Bidle KD, Haramaty L, Falkowski PG |journal=[[Limnology and Oceanography]] |volume=49 |issue=4 |pages=997–1005 |bibcode=2004LimOc..49..997B |doi-access=free}}</ref><ref name=Hu2019>{{cite journal | vauthors = Hu C, Rzymski P | title = Programmed Cell Death-Like and Accompanying Release of Microcystin in Freshwater Bloom-Forming Cyanobacterium ''Microcystis'': From Identification to Ecological Relevance | journal = Toxins | volume = 11 | issue = 12 | page = 706 | date = December 2019 | pmid = 31817272 | pmc = 6950475 | doi = 10.3390/toxins11120706 | doi-access = free }}</ref> and cell death has been suggested to play a key role in developmental processes, such as akinete and heterocyst differentiation, as well as strategy for population survival.<ref name="Programmed Cell Death-Like and Acco"/><ref>{{cite journal | vauthors = Rzymski P, Klimaszyk P, Jurczak T, Poniedziałek B | title = Oxidative Stress, Programmed Cell Death and Microcystin Release in ''Microcystis aeruginosa'' in Response to ''Daphnia'' Grazers | journal = Frontiers in Microbiology | volume = 11 | pages = 1201 | date = 2020 | pmid = 32625177 | pmc = 7311652 | doi = 10.3389/fmicb.2020.01201 | doi-access = free }}</ref><ref name="Meeks-2001">{{cite journal | vauthors = Meeks JC, Elhai J, Thiel T, Potts M, Larimer F, Lamerdin J, Predki P, Atlas R | display-authors = 6 | title = An overview of the genome of Nostoc punctiforme, a multicellular, symbiotic cyanobacterium | journal = Photosynthesis Research | volume = 70 | issue = 1 | pages = 85–106 | year = 2001 | pmid = 16228364 | doi = 10.1023/A:1013840025518 | bibcode = 2001PhoRe..70...85M }}</ref><ref name=Claessen2014 /><ref name=Aguilera2021 />

{{clear left}}