WHAT'S IT ALL ABOUT, ALGAE ??? Copyright Mark Thorson 1995, 1996 SBGA is the cyanobacteria (blue-green algae) known as _Aphanizomenon_flos-aquae_. Whether or not it is a good idea to eat this stuff may be judged by reviewing the scientific and medical literature. Quoting from _The_Lancet_, "Hazardous Freshwater Cyano- Bacteria (Blue-Green Algae)", June 12, 1993, volume 341, pages 1519 and 1520: "Cyanobacteria, especially members of the genera _Microcystis_, _Anabaena_, _Aphanizomenon_, and _Oscillatoria_, are common and potentially harmful inhabitants of freshwater. Many species contain lipopolysaccharide endotoxins, but also, more importantly, can produce several potent hepatotoxins (microcystins) and neurotoxins (eg, anatoxins, saxitoxin)." "Whenever a diagnosis of cyanobacterial intoxication is a possibility, it is essential (in the UK) to notify the local Consultant in Communicable Disease Control. Control measures may need to be instituted as a priority to minimize the risk to others. Furthermore, early notification of potential outbreaks will facilitate proper prospective epidemiological studies, which are essential if the risks from cyanobacteria are to be properly measured." Quoting from _Journal_of_Medical_Microbiology_, "Cyanobacteria and Human Health", 1992, volume 36, page 301: "_Aphanizomenon_flosaquae_ produces neosaxitoxin, which causes paralysis by reversibly blocking sodium conductance in neurones. In addition, lipopolysaccharide endotoxins have been demonstrated in some blooms. Some algal toxins are also potent tumor promoters in animal models." "It is clear that cyanobacteria are a potential hazard to human health." Quoting from _Nature_, "Fatal Attraction To Cyanobacteria", September 10, 1992, volume 359, page 110: "The buoyant growth habit of the widely encountered toxigenic, planktonic genera such as _Microcystis_, _Anabaena_, _Aphanizomenon_, _Nodularia_ and some _Oscillatoria_ species can result in scum formation in lakes and ponds during calm weather, so that an acutely toxic dose of cyanobacterial toxins can be presented ..." Quoting from _Journal_of_Applied_Phycology_, "Anatoxin-A Concentration in _Anabaena_ and _Aphanizomenon_ Under Different Environmental Conditions And Comparison Of Growth By Toxic And Non-Toxic _Anabaena_ Strains: A Laboratory Study", 1993, volume 5, number 6, page 581: "Anatoxin-a-concentration in cells of _Anabaena_- and _Aphanizomenon_-strains and in their growth media were studied in the laboratory in batch cultures at different temperatures, light fluxes, orthophosphate and nitrate concentrations and with different nitrogen sources for growth." "The highest light flux studied did not limit the growth or decrease the level of the toxin in the cells of _Aphanizomenon_." Quoting from _Journal_of_Applied_Bacteriology_, "Cyanobacteria Secondary Metabolites--the Cyanotoxins", 1992, volume 72, pages 448 and 449: "The production of neurotoxin by _Aphanizomenon_ _flos-aquae_ was first demonstrated by Sawyer _et_al._ (1968). These neurotoxins were later shown to be saxitoxin (STX) and neosaxitoxin (NEOSTX) (LD50 i.p. mouse equals about 10 micrograms/kilogram), the two primary toxins of red tide paralytic shellfish poisoning (PSP)." "Acute hepatotoxicosis involving the hepatotoxins (liver toxins) is the most commonly encountered toxicosis involving cyanobacteria. These toxins are produced by strains of species within the genera _Microcystis_, _Anabaena_, _Nodularia_, _Oscillatoria_ and _Nostoc_. In addition, chemically undefined hepatotoxins are being studied in _Cylindrospermopsis_, _Aphanizomenon_, _Gloeotrichia_ and _Coelosphaerium_. Clinical signs of hepatotoxicosis have been observed in field poisonings involving cattle, sheep, horses, pigs, ducks and other wild and domestic animals. Most laboratory studies have involved the use of mice, rats, guinea pigs, rabbits and pigs. Collectively, the signs of poisoning in these animals include weakness, anorexia, pallor of mucous membranes, vomiting, cold extremities, and diarrheoa."