An akinete is an enveloped, thick-walled, non-motile, dormant cell formed by filamentous, heterocyst-forming cyanobacteria under the order Nostocales and Stigonematales. [1] [2] [3] [4] Akinetes are resistant to cold and desiccation. [1] They also accumulate and store various essential material, both of which allows the akinete to serve as a survival structure for up to many years. [1] [4] However, akinetes are not resistant to heat. [1] Akinetes usually develop in strings with each cell differentiating after another and this occurs next to heterocysts if they are present. [1] Development usually occurs during stationary phase and is triggered by unfavorable conditions such as insufficient light or nutrients, temperature, and saline levels in the environment. [1] [4] Once conditions become more favorable for growth, the akinete can then germinate back into a vegetative cell. [5] Increased light intensity, nutrients availability, oxygen availability, and changes in salinity are important triggers for germination. [5] In comparison to vegetative cells, akinetes are generally larger. [4] [6] This is associated with the accumulation of nucleic acids which is important for both dormancy and germination of the akinete. [6] Despite being a resting cell, it is still capable of some metabolic activities such as photosynthesis, protein synthesis, and carbon fixation, albeit at significantly lower levels. [3]
Akinetes can remain dormant for extended periods of time. Studies have shown that some species could be cultured that were 18 and 64 years old. [7]
Akinete formation also influences the perennial blooms of cyanobacteria. [8]
References
- ^ a b c d e f Adams, David; Duggan, Paula (Aug 1999). "Heterocyst and akinete differentiation in cyanobacteria". New Phytol. 144: 23–28. doi: 10.1046/j.1469-8137.1999.00505.x.
- ^ Moore, R. et al. (1998) Botany. 2nd Ed. WCB/McGraw Hill. ISBN 0-697-28623-1
- ^ a b Sukenik, Assaf; Beardall, John; Hadas, Ora (July 2007). "Photosynthetic Characterization of Developing and Mature Akinetes Ofaphanizomenon Ovalisporum(Cyanoprokaryota)1". Journal of Phycology. 43 (4): 780–788. Bibcode: 2007JPcgy..43..780S. doi: 10.1111/j.1529-8817.2007.00374.x. S2CID 85200692.
- ^ a b c d Sukenik, Assaf; Maldener, Iris; Delhaye, Thomas (September 2015). "Carbon assimilation and accumulation of cyanophycin during the development of dormant cells (akinetes) in the cyanobacterium Aphanizomenon ovalisporum". Front. Microbiol. 6: 1067. doi: 10.3389/fmicb.2015.01067. PMC 4586427. PMID 26483781.
- ^ a b Myers, Jackie; Beardall, John; Allinson, Graeme (July 2010). "Environmental influences on akinete germination and development in Nodularia spumigena (Cyanobacteriaceae), isolated from the Gippsland Lakes, Victoria, Australia". Hydrobiologia. 649 (1): 239–247. doi: 10.1007/s10750-010-0252-5. S2CID 23052084.
- ^ a b Sukenik, Assaf; Kaplan-Levy, Ruth; Mark, Jessica (March 2012). "Massive multiplication of genome and ribosomes in dormant cells (akinetes) of Aphanizomenon ovalisporum (Cyanobacteria)". The ISME Journal. 6 (3): 670–679. doi: 10.1038/ismej.2011.128. PMC 3280138. PMID 21975597.
- ^ David Livingstone & G.H.M. Jaworski (1980) The viability of akinetes of blue-green algae recovered from the sediments of Rostherne Mere, British Phycological Journal, 15:4, 357-364, DOI: 10.1080/00071618000650361
- ^ Myers, Jackie; Beardall, John (Aug 2011). "Potential triggers of akinete differentiation in Nodularia spumigena (Cyanobacteriaceae) isolated from Australia". Hydrobiologia. 671 (1): 165. doi: 10.1007/s10750-011-0714-4. S2CID 7949386.
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