Cyanobacteria and Cyanotoxins

From MicrobeWiki, the student-edited microbiology resource


Nostoc filamentous Cyanobacteria with heterocysts under a light microscope. Picture taken by Robert Calentine. [1].

By Mark Boniface

Cyanobacteria are a group of bacteria that harness their energy through the process of photosynthesis, absorbing the sun’s energy and converting it into usable energy. These bacteria get their name from their bluish-green color. These bacteria are significantly important in many ecosystems. Cyanobacteria are some of the only organisms that produce gaseous oxygen as a product of their photosynthetic process. Cyanobacteria, and their descendants, are credited with the production of all the oxygen gas on Earth. These bacteria are the cause of a massive blooming of biodiversity of aerobic organisms, and the cause of the near-extinction of oxygen-intolerant organisms.

Along with the production of essential and highly demanded oxygen gas and the fixing of carbon dioxide and nitrogen, cyanobacteria also can produce a variety of toxins. These harmful agents come primarily as neurotoxins, cytotoxins, endotoxins, or hapatotoxins. The cyanobacteria produce these toxins to kill off other local species to provide more room for growth. These toxins arise when the environment provides optimal for cyanobacteria to reproduce explosively and exponentially, resulting in algal blooms. These blooms are not only harmful for many aquatic species, but also for humans who ingest contaminated fish and shellfish or swim in or are exposed to contaminated water. It is thought that cyanobacteria are an environmental cause of degenerative neurological diseases such as Amyotrophic Lateral Sclerosis (ALS), Parkinson’s disease, and Alzheimer’s disease.

Cell Structure

Include some current research, with at least one figure showing data.

Section 2

Include some current research, with at least one figure showing data.

Section 3

Chemical strucutre of Anatoxin-a, a alkaloid neurotoxin produced by cyanobacteria that induced paralysis. Image created by wikipedia commons user Yikrazuul. [2].


[1] Hodgkin, J. and Partridge, F.A. "Caenorhabditis elegans meets microsporidia: the nematode killers from Paris." 2008. PLoS Biology 6:2634-2637.

Authored for BIOL 238 Microbiology, taught by Joan Slonczewski, 2015, Kenyon College.