Examine individual changes

'{{taxobox | image = Microcystis aeruginosa.jpeg | regnum = [[Bacteria]] | subregnum = [[Eubacteria]] | phylum = [[Cyanobacteria]] | classis = [[Cyanophyceae]] | ordo = [[Chroococcales]] | familia = [[Microcystaceae]] | genus = ''[[Microcystis]]'' | species = '''''M. aeruginosa''''' | binomial = ''Microcystis aeruginosa'' | binomial_authority = Kützing, 1846 }} '''''Microcystis aeruginosa''''' is a species of freshwater [[cyanobacteria]] which can form [[harmful algal bloom]]s of economic and ecological importance.<ref name=Oberholster>{{cite journal|last=Oberholster|first=PJ|title=Microcystis aeruginosa: source of toxic microcystins in drinking water|journal=African Journal of Biotechnology|volume=3|issue=3|pages=159–168|url=http://www.ajol.info/index.php/ajb/article/view/14935|accessdate=August 4, 2014|doi=10.5897/AJB2004.000-2029|year=2003}}</ref> They are the most common toxic cyanobacterial bloom in [[eutrophic]] fresh water.<ref name=Oberholster/> Cyanobacteria produce neurotoxins and peptide hepatotoxins, such as [[microcystin]] and [[cyanopeptolin]].<ref>{{cite journal|url=https://www.duo.uio.no/handle/10852/11331|title=On the Evolution of Nonribosomal Peptide Synthetase Gene Clusters in Cyanobacteria|year=2007|publisher=University of Oslo|last1=Tooming-Klunderud|first1=Ave}}</ref> ==Characteristics== [[Image:Erie sat blue.jpg|left|thumb|250px|[[NOAA]] MERIS image of large cyanobacterial bloom confirmed as ''M. aeruginosa''<ref name="Western Lake Erie (Maumee River) Microcystis bloom">{{cite web|title=Ecosystem Research and Harmful Algal Blooms|url=http://www.glerl.noaa.gov/res/Centers/HumanHealth/ecosystem_research.html|work=Center of Excellence for Great Lakes and Human Health|publisher=NOAA|accessdate=27 June 2011}}</ref>]] [[File:Microcystis aeruginosa outbreak on the southwest side of Lake Albert 1.jpg|thumb|Microcystis aeruginosa outbreak on [[Lake Albert (New South Wales)|Lake Albert]] in [[Wagga Wagga]], Australia]] As the etymological derivation implies, ''Microcystis'' is characterized by small cells (of only a few [[micrometre|micrometers]] diameter), which lack individual sheaths.<ref>{{cite web|title=Cyanobacteria: Microcystis |url=http://silicasecchidisk.conncoll.edu/LucidKeys/Carolina_Key/html/Microcystis_Main.html |work=The Silica Secchi Disk |publisher=Connecticut College: The SilicaSecchi Disk |accessdate=24 June 2011 |deadurl=yes |archiveurl=https://web.archive.org/web/20080326200658/http://silicasecchidisk.conncoll.edu/LucidKeys/Carolina_Key/html/Microcystis_Main.html |archivedate=26 March 2008 |df= }}</ref> Cells usually are organized into colonies (large colonies of which may be viewed with the naked eye) that begin in a spherical shape, but lose their coherence to become perforated or irregularly shaped over time.{{citation needed|date=June 2015}} The [[protoplast]] is a light blue-green color, appearing dark or brown due to optical effects of gas-filled [[Vesicle (biology)|vesicles]]; this can be useful as a distinguishing characteristic when using light [[microscopy]]. These vesicles provide the buoyancy necessary for ''M. aeruginosa'' to stay at a level within the [[water column]] at which they can obtain optimum light and carbon dioxide levels for rapid growth. == Ecology == ''M. aeruginosa'' is favored by warm temperatures, but toxicity and maximal growth rates are not totally coupled, as the cyanobacterium has highest laboratory growth rates at 32&nbsp;°C, while toxicity is highest at 20&nbsp;°C, lowering in toxicity as a function of increasing temperatures in excess of 28&nbsp;°C. Growth has been found to be limited below 15&nbsp;°C. The aquatic plant ''[[Myriophyllum spicatum]]'' produces [[ellagic acid|ellagic]], [[gallic acid|gallic]], and [[pyrogallic acid]]s and (+)-[[catechin]], allelopathic polyphenols inhibiting the growth of ''M. aeruginosa''.<ref name=Nakai>Myriophyllum spicatum-released allelopathic polyphenols inhibiting growth of blue-greenalgaeMicrocystis aeruginosa. Satoshi Nakai, Yutaka Inoue, Masaaki Hosomi and Akihiko Murakami, Water Research, Volume 34, Issue 11, 1 August 2000, Pages 3026–3032, {{doi|10.1016/S0043-1354(00)00039-7}}</ref> ==Toxins== {{see also|Cyanotoxin}} ''M. aeruginosa'' can produce both [[neurotoxins]] ([[lipopolysaccharides]]-LPSs)<ref name="LPS toxicity Microcystis">{{cite journal|last=Mayer|first=Alejandro M. S.|author2=Jonathan A. Clifford|title=Cyanobacterial Microcystis aeruginosa Lipopolysaccharide Elicits Release of Superoxide Anion, Thromboxane B2, Cytokines, Chemokines, and Matrix Metalloproteinase-9 by Rat Microglia|journal=[[Toxicological Sciences]]|date=May 2011|volume=121|issue=1|url=http://toxsci.oxfordjournals.org/content/121/1/63.short?rss=1|accessdate=25 June 2011}}</ref> and [[hepatotoxins]] ([[microcystin]]s). ==Economic importance== Because of ''M. aeruginosa''´s microcystin toxin production under the right environmental conditions, it can be a source of [[drinking water pollution]].<ref>{{cite web|title=Cyanobacterial Toxins: Microcystin-LR in drinking water|url=https://docs.google.com/viewer?a=v&q=cache:hB3G0xgpX3wJ:www.who.int/water_sanitation_health/dwq/chemicals/cyanobactoxins.pdf+microcystis+aeruginosa+drinking+water&hl=en&gl=us&pid=bl&srcid=ADGEEShcbKCATULdoWmYMmdDDfKwkvn9AGxBiBjfD74GLQKBu2-IxU8u1OVVbVugaxxqc6DQqe50Pmj7xLim9GPFB9i6LHxN5KjoBimSZXBLAIJ3buRhH9nGmCkHiF3O0xOWqsk2qLiY&sig=AHIEtbSVIloCd3Jyb6SYRqRn-8oLPhlUNg|work=Background document for development of WHO Guidelines for Drinking Water Quality|publisher=World Health Organization (WHO)|accessdate=24 June 2011}}</ref> water quality mitigation measures in the form of water filtration facilities can lead to increased economic costs as well as damage to local tourism caused by lake or other waterway closures.<ref name="Effects on tourism and local water quality">{{cite web|last=Somek |first=Hasim |title=A Case Report: Algal Bloom of Microcystis aeruginosa in a Drinking-Water Body, Eğirdir Lake, Turkey |url=http://www.trjfas.org/pdf/issue_8_1/177_179.pdf |publisher=Turkish Journal of Fisheries and Aquatic Sciences |accessdate=27 June 2011 |deadurl=yes |archiveurl=https://web.archive.org/web/20111004044736/http://www.trjfas.org/pdf/issue_8_1/177_179.pdf |archivedate=4 October 2011 |df= }}</ref> ''M. aeruginosa'' is the subject of research into the natural production of [[butylated hydroxytoluene]] (BHT),<ref name="BHTalgae">{{cite journal |author=Babu B, Wu JT |title=Production of Natural Butylated Hydroxytoluene as an Antioxidant by Freshwater Phytoplankton |journal=Journal of Phycology |volume=44 |issue=6 |pages=1447–1454 |date=December 2008 |url=http://ntur.lib.ntu.edu.tw/bitstream/246246/162863/1/22.pdf |doi=10.1111/j.1529-8817.2008.00596.x |pmid=27039859}}</ref> an antioxidant, food additive, and industrial chemical. ==Ecological importance== In 2009, unprecedented mammal mortality in the southern part of the [[Kruger National Park]] led to an investigation which implicated ''M. aeruginosa''. The dead animals included grazers and browsers which preferred drinking from the leeward side of two dams, a natural point of accumulation for drifting ''Microcystis'' blooms. Mammals such as elephants and buffalo which usually wade into water before drinking, were unaffected, as were the resident crocodiles. The source of nutrients which supported the ''Microcystis'' growth was narrowed down to the dung and urine voided in the water by a large resident hippo population, unaffected by the bloom. The immediate problem was solved by breaching of the dam walls and draining of the water. ''M. aeruginosa'' is the most abundant cyanobacterial genus in South Africa, may be a toxic or a harmless strains.<ref>Paul J. Oberholster, Jan G. Myburgh, Danny Govender, Roy Bengis, Anna-Maria Botha [http://repository.up.ac.za/bitstream/handle/2263/9278/Oberholster_Identification%282009%29.pdf?sequence=1 Identification of toxigenic Microcystis strains after incidents of wild animal mortalities in the Kruger National Park, South Africa.] Ecotoxicology and Environmental Safety (2009), Elsevier {{DOI|10.1016/j.ecoenv.2008.12.014}}</ref> Some South African water bodies are now highly contaminated, mostly from return flows out of dysfunctional waste water treatment works that discharge over 4 billion liters of untreated, or at best partially treated sewage into receiving rivers ever day, with Hartebeestpoort Dam being among the worst.<ref>Turton, A.R. 2015. Sitting on the Horns of a Dilemma: Water as a Strategic Resource in South Africa. In @Liberty, No 6, Issue 22. Johannesburg: South African Institute of Race Relations. Available online http://irr.org.za/reports-and-publications/atLiberty/files/liberty-2013-sitting-on-the-horns-of-a-dilemma-2013-water-as-a-strategic-resource-in-south-africa</ref> Microcystin has been linked to the death of sea otters in 2010, a threatened species in the US.<ref>{{cite news|last1=Stephens|first1=Tim|title=Sea otter deaths linked to toxin from freshwater bacteria|url=http://news.ucsc.edu/2010/09/otter-toxin.html|publisher=UC Santa Cruz Newscenter|date=September 10, 2010}}</ref> The poisoning probably resulted from eating contaminated bivalves often consumed by sea otters and humans. The researchers noted that such bivalves in the area exhibited significant biomagnification (to 107 times ambient water levels) of microcystin.<ref>{{cite journal|last1=Miller|first1=Melissa|title=Evidence for a Novel Marine Harmful Algal Bloom: Cyanotoxin (Microcystin) Transfer from Land to Sea Otters|journal=PLOS ONE|date=2010-09-10|doi=10.1371/journal.pone.0012576|pmid=20844747|pmc=2936937|volume=5|issue=9|pages=e12576}}</ref> === Glyphosate metabolism === Algal blooms of cyanobacteria thrive in the large phosphorus content of agricultural runoff. Besides consuming phosphorus, ''M. aeruginosa'' thrives on glyphosate, although high concentrations may inhibit it.<ref>{{cite journal|last1=Qiu|first1=Huimin|title=Physiological and biochemical responses of Microcystis aeruginosa to glyphosate and its Roundup® formulation|journal=Journal of Hazardous Materials|date=2013-03-15|volume=248–249|pages=172–176|pmid=23357506|url=http://www.sciencedirect.com/science/article/pii/S0304389412012010|doi=10.1016/j.jhazmat.2012.12.033}}</ref> ''M. aeruginosa'' has shown glyphosate resistance as result of preselective mutations, and glyphosate presence serves as an advantage to this and other microbes that are able to tolerate its effects, while killing those less tolerant.<ref>{{cite journal|title=Resistance to glyphosate in the cyanobacterium Microcystis aeruginosa as result of pre-selective mutations|journal=Evolutionary Ecology|date=2007-07-01|volume=21|issue=4|pages=535–547|doi=10.1007/s10682-006-9134-8|last1=López-Rodas|first1=Victoria|last2=Flores-Moya|first2=Antonio|last3=Maneiro|first3=Emilia|last4=Perdigones|first4=Nieves|last5=Marva|first5=Fernando|last6=García|first6=Marta E.|last7=Costas|first7=Eduardo}}</ref> ==See also== *[[Cyanotoxin]] *[[Harmful algal blooms]] ==References== {{Reflist}} {{Taxonbar|from=Q3555762}} [[Category:Chroococcales]] [[Category:Bacteria described in 1846]]'