Bajpai Pankaj et al. IRJP 2012, 3 (2)

INTERNATIONAL RESEARCH JOURNAL OF PHARMACY www.irjponline.com

ISSN 2230 – 8407

Review Article

1

CYNOBACTERIA: A COMPREHENSIVE REVIEW Gothalwal Ragini2, Bajpai Pankaj1* School of Biotechnology, Guru Ghasidas University, Bilaspur, Chhattisgarh, India 2 Reader, Department of Biotech Barkatullah University, Bhopal, (M.P), India Article Received on: 09/12/11 Revised on: 16/01/12 Approved for publication: 17/02/12

*Email: [email protected] ABSTRACT Microorganisms are the natural habitants of environment, persisting in typically three types of conditions. They are saprophytic, parasitic and symbiotic. Symbiotic condition is when both the parasite and the host are benefited from each other in natural ecological conditions. Cyanobacteria is related with the symbiotic nature benefiting the natural environment with a number of aspects in agriculture fields, biotech fields, pharmaceuticals, food and many other related fields. Cyanobacteria are aquatic and photosynthetic, that is, they live in the water, and can manufacture their own food. Because they are bacteria, they are quite small and usually unicellular, though they often grow in colonies large enough to see. They have the distinction of being the oldest known fossils, more than 3.5 billion years old. The above article is a sincere effort to bring out the summarized information of the above microorganism. Keywords: cyanobacteria, Uses, characters, Symbiosis.

INTRODUCTION A microorganism or microbe is a microscopic organism that comprises either a single cell (unicellular) or, cell clusters, or no cell at all (acellular). Microorganisms are very diverse; they include bacteria, fungi, archaea, and protists. Microscopic plants such as green algae, and animals such as plankton and the planarian. Some microbiologists also include viruses, but others consider these as non-living. Most microorganisms are unicellular (single-celled), but this is not universal, since some multicellular organisms are microscopic, while some unicellular protists and bacteria, like Thiomargarita namibiensis, are macroscopic and visible to the naked eye. Microorganisms live in all parts of the biosphere where there is liquid water, including soil, hot springs, on the ocean floor, high in the atmosphere and deep inside rocks within the Earth's crust. Microorganisms are critical to nutrient recycling in ecosystems as they act as decomposers. As some microorganisms can fix nitrogen, they are a vital part of the nitrogen cycle, and recent studies indicate that airborne microbes may play a role in precipitation and weather. Microbes are also exploited by people in biotechnology, both in traditional food and beverage preparation, and in modern technologies based on genetic engineering. However, pathogenic microbes are harmful, since they invade and grow within other organisms, causing diseases that kill humans, other animals and plants1-3. The use of microbes and to bring out change in them as desire for any continent use may be called as biotech. Biotechnology is a field of applied biology that involves the use of living organisms and bioprocesses in engineering, technology, medicine and other fields requiring bioproducts. Biotechnology also utilizes these products for manufacturing purpose. Modern use of similar terms includes genetic engineering as well as cell- and tissue culture technologies. The concept encompasses a wide range of procedures for modifying living organisms according to human purposes such as going back to domestication of animals, cultivation of plants, and "improvements" to these through breeding programs that employ artificial selection and hybridization. By comparison to biotechnology, bioengineering is generally thought of as a related field with its emphasis more on higher

systems approaches for interfacing with and utilizing living things4, 5. Cyanobacteria As the name suggest the above organism is a bacteria. But I have received few other names such as blue-green algae, blue-green bacteria, and Cyanophyta) is a phylum of bacteria that obtain their energy through photosynthesis. The name "cyanobacteria" comes from the color of the bacteria. The ability of cyanobacteria to perform oxygenic photosynthesis is thought to have converted the early reducing atmosphere into an oxidizing one, which dramatically changed the composition of life forms on Earth by stimulating biodiversity and leading to the near-extinction of oxygen in tolerance. According to endosymbiotic theory, chloroplasts in plants and eukaryotic algae have evolved from cyanobacterial ancestors via endosymbiosis. Many Proterozoic oil deposits are attributed to the activity of cyanobacteria. They are also important providers of nitrogen fertilizer in the cultivation of rice and beans. The cyanobacteria have also been tremendously important in shaping the course of evolution and ecological change throughout earth's history. The other great contribution of the cyanobacteria is the origin of plants. The chloroplast with which plants make food for themselves is actually a cyanobacterium living within the plant's cells. Sometime in the late Proterozoic, or in the early Cambrian, cyanobacteria began to take up residence within certain eukaryote cells, making food for the eukaryote host in return for a home. This event is known asendosymbiosis, and is also the origin of the eukaryotic mitochondrion. Because they are photosynthetic and aquatic, cyanobacteria are often called "blue-green algae". This name is convenient for talking about organisms in the water that make their own food, but does not reflect any relationship between the cyanobacteria and other organisms called algae. Cyanobacteria are relatives of the bacteria, not eukaryotes, and it is only the chloroplast in eukaryotic algae to which the cyanobacteria are related6. The organisum have been described visually in figure number 1 and 2.

Page 53

Bajpai Pankaj et al. IRJP 2012, 3 (2)

Figure 1

Figure 2

Morphology and Ecology The above organism is basically found in terrestrial and aquatic habitat, from oceans to fresh water to bare rock to soil. They can occur as planktonic cells or form phototrophic bio films in fresh water and marine environments, they occur in damp soil, or even on temporarily moistened rocks in deserts. A few are endosymbionts in lichens, plants, various protists, or sponges and provide energy for the host. Some live in the fur of sloths, providing a form of camouflage. Aquatic cyanobacteria are probably best known for the extensive and highly visible blooms that can form in both freshwater and the marine environment and can have the appearance of blue-green paint or scum. The association of toxicity with such blooms has frequently led to the closure of recreational waters when blooms are observed. Marine bacteriophages are a significant parasite of unicellular marine cyanobacteria. Many cyanobacteria also form motile filaments, called hormogonia, that travel away from the main biomass to bud and form new colonies elsewhere. The cells in a hormogonium are often thinner than in the vegetative state, and the cells on either end of the motile chain may be tapered. In order to break away from the parent colony, a hormogonium often must tear apart a weaker cell in a filament, called a necridium. Each individual cell of a cyanobacterium typically has a thick, gelatinous cell wall. They lack flagella, but hormogonia and some species may move about by gliding along surfaces. Many of the multicellular filamentous forms of Oscillatoria are capable of a waving motion; the filament oscillates back and forth. In water columns some cyanobacteria float by forming gas vesicles, like in archaea. These vesicles are not organelles as such. They are not bounded by lipid membranes but by a protein sheath7, 8. Cyanobacteria and Photosynthesis The above bacteria got its name cyanobacteria because of the fact that it possesses bluish pigment phycocyanin, which they use to capture light for photosynthesis. They also contain chlorophyll a, the same photosynthetic pigment that plants use. In fact the chloroplast in plants is a symbiotic cyanobacterium, taken up by a green algal ancestor of the plants sometime in the Precambrian. However, not all "bluegreen" bacteria are blue; some common forms are red or pink from the pigment phycoerythrin. These bacteria are often found growing on greenhouse glass, or around sinks and drains. Cyanobacteria account for 20–30% of Earth's photosynthetic productivity and convert solar energy into biomass-stored chemical energy at the rate of ~450 TW. Cyanobacteria utilize the energy of sunlight to drive photosynthesis, a process where the energy of light is used to split water molecules into oxygen, protons, and electrons. While most of the high-energy electrons derived from water are utilized by the cyanobacterial cells for their

own needs, a fraction of these electrons are donated to the external environment via electrogenic activity. Cyanobacterial electrogenic activity is an important microbiological conduit of solar energy into the biosphere 9, 10 . Cyanobacteria and it’s Relation with Nitrogen Fixation Cyanobacteria are useful for the growth of other plants. They are one of very few groups of organisms that can convert inert atmospheric nitrogen into an organic form, such as nitrate or ammonia. It is these "fixed" forms of nitrogen which plants need for their growth, and must obtain from the soil. Cyanobacteria include unicellular and colonial species. Colonies may form filaments, sheets or even hollow balls. Some filamentous colonies show the ability to differentiate into several different cell types: vegetative cells, the normal, photosynthetic cells that are formed under favorable growing conditions; akinetes, the climate-resistant spores that may form when environmental conditions become harsh; and thick-walled heterocysts, which contain the enzyme nitrogenase, vital for nitrogen fixation.. Nitrification cannot occur in the presence of oxygen, so nitrogen is fixed in specialized cells called heterocysts. These cells have an especially thickened wall that contains an anaerobic environment. Heterocyst-forming species are specialized for nitrogen fixation and are able to fix nitrogen gas into ammonia (NH3), nitrites (NO2-) or nitrates (NO3-) which can be absorbed by plants and converted to protein and nucleic acids (atmospheric nitrogen is not bioavailable to plants). Rice plantations utilize healthy populations of nitrogen-fixing cyanobacteria (Anabaena, as symbiotes of the aquatic fern Azolla) for use as rice paddy fertilizer. Biofertilizer of Rice Many studies have been reported on the use of dried cyanobacteria to inoculate soils as a means of aiding fertility, and the effect of adding cyanobacteria to soil on rice yield was first studied in the 1950s in Japan. The term ‘algalization’ is now applied to the use of a defined mixture of cyanobacterial species to inoculate soil, and research on algalization is going on in all major rice producing countries. The average of the results from all these studies have shown an increase in grain yield of 15-20% in field experiments. It has been suggested that the cyanobacteria introduced as a result of algalization can establish themselves permanently if inoculation is done consecutively for 3-4 cropping seasons. The basic method of mass production involves a mixture of nitrogen fixing cyanobacteria in shallow trays or polythene lined pits filled with water kept in open air, using clean, sieved farm soil as a carrier material. To each pit 10 kg soil and 250 g single super phosphate is added and water is filled upto a height of 12-15 cm. Starter culture, a mixture of Anabaena, Nostoc, Aulosira and Tolypothrix, is inoculated in each multiplication unit. Malathion (5-10 ml per tank) or carbofuran (3% granules, 20 g per tank) is also added to prevent insect breeding. In hot summer months, the cyanobacteria form a thick mat over the surface after 10-12 days of growth in open sun. The contents are allowed to dry and the dried flakes are collected, packed and used to inoculate rice fields. The basic advantage of this technology is that farmers after getting the soil based starter culture can produce the biofertilizer on their own with minimum additional inputs. An inoculum of 10-12 kg is considered sufficient to inoculate one hectare of paddy field 3-4 days after transplantation. The best results appear to be obtained when mixed inocula are produced from local stocks, and the Page 54

Bajpai Pankaj et al. IRJP 2012, 3 (2) biofertilizers are used in combination with a low level of nitrogenous fertilizer 11-15. Cyanobacterial Metabolites effect on Aquaculture Aquaculture is the fastest growing animal food sector, and cultured fish supply now provides over 13% of the animal protein intake for the human population. As catch rates of wild fisheries have leveled off or declined since the 1970s, aquaculture farming has grown to offset the increased demand. To meet the increasing demand the use of artificial

fertilizer which mimic the natural nitrogen source and other healthy condition are common. Cyanobacteria have been used in aquatic condition to increase the productivity. As the advantages of using the artificial means are numerous just that the disadvantages are also numerous. The metabolites or the secondary metabolites produced for the cyanobacteria in reverse cause damage to the aquatic ecosystem. The metabolites and the disadvantage or harm caused by them are . described in a figure bellow16-22

Figure 3: Metabolites of cyanobacteria and the damage cause by them.

Figure 4: Chemical structures of A: microcystins (I) and nodularins (II) (X and Z are variable amino acids, R = H or CH3). B: cylindrospermopsin C: anatoxin-a (I) and homoanatoxin-a (II) D: anatoxin-a(s). E: PSPs. F: lyngbyatoxin A. G: lipopolysaccharides (LPS)54. Table 1: Toxin and there lethal dose

Page 55

Bajpai Pankaj et al. IRJP 2012, 3 (2) Cyanobacterial Toxins and Humans Toxins of cyanobacteria are grouped in two main categories namely, biotoxins and cytotoxins based on the types of bioassays used to screen for their activity. Cytotoxins are detected by mammalian cell lines and biotoxins are assayed with small animals, e.g. mice or aquatic invertebrates. Biotoxins of cyanobacteria are water-soluble and heat stable and they are released upon aging or lysis of the cells. The primary types of cyanobacterial biotoxins include hepatotoxin (microcystins, nodularins, cylindrospermopsins), neurotoxin (anatoxins, saxitoxins) and dermatotoxins (lyngbyatoxin A, aplysiatoxins, lipopolysaccharides) 13. Hepatotoxins Hepatotoxins are low molecular weight cyclic peptide toxins that affect the liver and have been the predominant toxins involved in the case of freshwater algae toxicosis. Microcystins and nodularins Microcystin are a cyclic heptapeptides with about 65 different isoforms identified, with diverse levels of toxicity. Nodularins are pentapeptides with only four forms been described. The hepatospecificity of these toxins is due to the requirement for uptake by a bile acid transporter. Microcystin and nodularins have been shown to be inhibitors of serine/threonine protein phosphatase 1 and 2A. This inhibition leads to hyperphosphorylation of proteins associated with the cytoskeleton in hepatocytes 23, 24. Cylindrospermopsins Cylindrospermopsins is an alkaloid containing a tricyclic guanidine combined with hydroxymethyl uracyl and is stable to boiling. Studies on the mechanism of action of cylindrospermopsin have shown that in mouse hepatocytes in vivo the toxin disrupts protein synthesis. The main target of this toxin is the liver, but unlike the microcystins, it can affect other organs such as the lungs, kidneys, adrenals and intestine. Genotoxic activity is caused by the ability of cylindrospermopsins to induce strand breaks at the DNA level and loss of whole chromosomes 25-27. Neurotoxins The neurotoxins are known to be produced by freshwater cyanobacteria strains include anatoxin-a, anatoxin-a(s) and saxitoxins. Neurotoxins producing death by paralysis of peripheral skeletal muscles, then respiratory muscles leading to respiratory arrest in a few minutes to a few hours following exposure. Anatoxins Anatoxin-a are produced by species and strains of the genera Anabaena and Oscillatoria and is a secondary amine, 2acetyl-9azabicyclo(4.2.1)non-2-ene. This alkaloid, astructural analogue of cocaine, is a potent postsynaptic cholinergic nicotinic agonist, which causes a depolarizing neuromuscular blockade, followed by fatigue and paralysis. Anatoxin-a(s) is unrelated to anatoxin-a. Structurally it is a unique N-hydroxyguanidine methyl phosphate ester. It can be called a natural organophosphate because of its ability to irreversibly inhibit acetylcholinesterase, causing the same clinical end result as anatoxin-a. Blood, lung and muscle acetylcholinesterases are inhibited, whereas retina and brain acetylcholinesterase activities are normal 28, 29. Saxitoxins Saxitoxins or paralytic shellfish poisons are produced by species and strains of freshwater cyanobacteria Anabaena and Aphanizomenon, but are better known as the products of dinoflagellates, the marine algae responsible for red-tide paralytic shellfish poisoning. The saxitoxins or paralystic shellfish poisons inhibit nerve conduction by blocking

sodium channels in axons, thereby preventing the release of acetylcholine at neuromuscular junctions with resultant muscle paralysis. The paralysis of the respiratory muscles leads to the death of animals within a few minutes30. Dermatotoxins Dermatotoxins lyngbyatoxin A and aplysiatoxin are produced by the cyanobacterium Lyngbya majuscula, a marine benthic cyanobacterium with different metabolite constituents in deep and shallow water varieties. While the deep water varieties produce inflammatory substances and tumor promoters, the shallow water forms produce lipophilic substances, malyngamides A, B and C. Clinical signs include skin, eye and respiratory irritation31. Effect of Microcystis (Cyanotoxide) on Animal Models The chronic administration of Microcystis extract in the drinking water of mice resulted in increased mortality, particularly in male mice, together with chronic active liver injury. The deaths were largely due to endemic bronchopneumonia, indicating an impairment of disease resistance. Only six tumors were seen in the 430 mice killed at intervals up to 57 weeks of age; however, four of the six tumors were in females that ingested the highest Microcystis concentration. This result led to an investigation of the tumor-promoting activity of orally administered Microcystis in mice that had dimethylbenzanthracene applied to their skin. Results of these trials showed that there were significant increases in the growth of skin papillomas in mice given Microcystis but not Anabaena to drink. The finding that microcystin activated phosphorylase A preceded studies showing that microcystin-LR, - YR, and -RR, and nodularin are potent inhibitors of protein phosphatases type 1 and type 2A. This inhibition leads to hyperphosphorylation of proteins associated with the cytoskeleton in hepatocytes. The rapid loss of the sinusoidal architecture and attachment to one another leads to the accumulation of blood in the liver, and death most often results from hemorrhagic shock. These experiments clearly indicate that microcystin are a health threat in drinking water supplies32-34. Cyanobacteria and it’s Effect on Paddy Field Earlier we have discussed the use of cynaobacteria as biofetilizer for rice. A study to determine the physical and biological parameter of soil and also the difference between the growths of rice when the cyanobacteria used have been demonstrated. The methodology and the result of the study have been summarized under. cyanobacteria (Blue-Green Algae, BGA) were isolated, identified, multiplied and used as an inoculums in pot rice experiment. The pH, moisture and algal population were measured in four seasons. The highest and lowest pH (6.7, 6.2), moisture of soil (43%, 34%) and algal population (12, 20 Colony-Forming Units/50 ml on A and B medium and 4, 5 Colony-Forming Units/50 ml on A and B medium) were recorded in spring and winter, respectively. The only heterocystous cyanobacteria were found in soil samples identified as Anabaena with four species (A. spiroides, A. variabilis, A. torulosa and A. osillarioides). The germination of rice seeds treated with cyanobacteria was faster than control. The result of pot experiment were: increase of 53% in plant height; 66% in roots length; 58% in fresh leaf and stem weight; 80% in fresh root weight; 125% in dry leaf and stem weight; 150% in dry root weight; 20% in soil moisture; 28% in soil porosity and a decrease of 9.8% in soil bulk density and 4.8% in soil particle density. It was demonstrated that this technology can be a powerful means of enriching the soil fertility and improving rice crop yields. Page 56

Bajpai Pankaj et al. IRJP 2012, 3 (2) CONCLUSION Cyanobacteria as we have discussed has a number of applications over different fields such as aquaculture, agriculture, biotechnology etc. which can out break a quantity of desired requirements of human being. The symbiotic phenomenon relating the secondary metabolites of the organism can be utilized for improving crop products, deterioration of heavy metals, nitrogen fixation and biofertilizers for paddy fields etc. Other than these numbers of researches are going on for better utilization of cyanobacterial genera. This review is a sincere affort to out break the advantages of environmental habitants like cyanobacteria as priority for the betterment of human life. REFERENCES 1. Madigan M, Martinko J (editors) Brock Biology of Microorganisms (13th ed.), (2006). Pearson Education. p. 1096. 2. Rybicki EP . "The classification of organisms at the edge of life, or problems with virus systematics". S Aft J Sci, (1990): 86: 182–6. 3. LWOFF A "The concept of virus". J. Gen. Microbiol. (1956). 17 (2): 239–53. 4. Thieman, W.J, Palladino, M.A. Introduction to Biotechnology, Ist edition, (2008)., Pearson&Benjamin Cummings. 5. Springham, D.; Springham, G, Moses, V, Cape, R.E. Biotechnology: The Science and the Business; 3rd edition (2005), CRC Press. 6. http://www.ucmp.berkeley.edu/bacteria/cyanomm/introduction.html. 7. http://sciam.com/article.cfm?chanID=sa022&articleID=0005BE470078-1FA8 807883414B7F0000, Steve Nadis, The Cells That Rule the Seas, Scientific American, 8. Stewart I and Falconer IR "Cyanobacteria and cyanobacterial toxins", Eds: Walsh PJ, Smith SL and Fleming LE. in Oceans and human health: risks and remedies from the seas, Academic Press, , Pages 271–296. 9. Pisciotta JM, Zou Y, Baskakov IV. Yang, edited by Ching-Hong. "Light-Dependent Electrogenic Activity of Cyanobacteria". PLoS ONE, (2010), 5 (5): e1082. 10. http://www.ucmp.berkeley.edu/bacteria/cyanomm/life and ecology of cynobacteria.html. 11. Upasana Mishra and Sunil Pabbi, Cyanobacteria: A Potential Biofertilizer for Rice, RESONANCE, Indian journal of Agriculture methologies, June 2004, (1998). 17 (2): 239–53. 12. P K De, The role of blue green algae in nitrogen fixation in rice fields, Proc. Royal Society of London, (1939):Vol. 127, pp. 129-139, 13. A Watanabe, R Ito and C Konishi, Effect of nitrogen fixing blue green algae on the growth of rice plants, Nature, (1951) Vol.168, pp. 748-749. 14. G S Venkataraman, Algal biofertilizers and rice cultivation, Ist edition (1972),Today and Tommorrow Printers and Publishers, Faridabad, India, pp. 248-251. 15. P K Singh, D W Dhar, S Pabbi, R Prasanna and A Arora (Editors), Biofertilizers: Blue Green Algae and Azolla, IARI, Venus publication, New Delhi, India, (1991), pp. 123-129. 16. Agrawal, M.K., Bagchi, D., Bagchi, S.N.,. Acute inhibition of protease and suppression of growth in zooplankter, Moina macrocopa, by Microcystis blooms collected in Central India. Journal of Hydrobiologia, (2001) 464, 37–44. 17. Agrawal, M.K., Bagchi, D., Bagchi, S.N., Cysteine and serine proteasemediated proteolysis in body homogenate of a zooplankter, Moina macrocopa, is inhibited by the toxic cyanobacterium, Microcystis aeruginosa PCC7806. Comp. Biochem. Physiol., Part B Biochem. Mol. Biol. 141, 33–41. 18. Agrawal, M.K., Zitt, A., Bagchi, D., Weckesser, J., Bagchi, S.N., Von Elert, E., 2005b. Characterization of proteases in guts of Daphnia magna and their inhibition by Microcystis aeruginosa PCC 7806. Journal of Environ. Toxicol. 20, 314–322. 19. Banker, R., Carmeli, S., 1999. Inhibitors of serine proteases from a waterbloom of the cyanobacterium Microcystis sp. Tetrahedron 55, 10835–10844. Banker, R., Carmeli, S.,Werman, M., Teltsch, B., Porat,

20.

21.

22. 23.

24.

25.

26.

27.

28. 29.

30. 31. 32.

33.

34.

35.

R., Sukenik, A., 2001. Uracil moiety is required for toxicity of the cyanobacterial hepatotoxin cylindrospermopsin. J. Toxicol. Environ. Health, Part A 62, 281–288. Beattie, K.A., Ressler, J., Wiegand, C., Krause, E., Codd, G.A., Steinberg, C.E., Pflugmacher, S., 2003. Comparative effects and metabolism of two microcystins and nodularin in the brine shrimp Artemia salina. Aquat. Toxicol. 62, 219–226. Fischer, W.J., Altheimer, S., Cattori, V., Meier, P.J., Dietrich, D.R., Hagenbuch, B., 2005. Organic anion transporting polypeptides expressed in liver and brain mediate uptake of microcystin. Toxicol. Appl. Pharmacol. 203, 257–263. From, J., Horlyck, V., 1984. Sites of uptake of geosmin, a cause of earthy-flavor, in rainbow trout (Salmo gairdneri). Can. J. Fish Aquat. Sci. 41, 1224–1226. Sivonen, K. and Jones, G. Cyanobacterial toxins, In: Toxic Cyanobacteria in Water, a Guide of Their Public Health Consequences, Monitoring and Management. I. edited by Chorus and J. Bartram (1999), E &FN Spon, London, pp. 41-111. Tiovola, D. M., Goldman R. D., Garrod, D. R. and Eriksson, J. E. Protein phosphatases maintain the organization and structural interactions of hepatic keratin intermediate filaments. J. Cell Sci, (1997) . 100: 23-33. Tereo, K., Ohmori, S., Igarashi, K., Ohtani, I., Harada, K-I., Ito, E. and Watanabe, M. Electron microscopic studies on experimental poisoning in mice induced by cylindrospermopsin isolated from bluegreen alga Umezakia natans. Toxicon, (1994) 32: 833-843. Falconer, I. R.. Algal toxins and human health. In: J.H. Rubec (ed). The handbook of environmental chemistry. 5 Part C. Quality and treatment of drinking water II (1998). Springer-Verlag publication, Berlin. pp. 5382. Humpage, A. R., Fenech, M., Thomas, P. and Falconer, I. R. Micronucleus induction and chromosome loss in transformed human white cells indicate clastogenic and aneugenic action of the cyanobacterial toxin, cylindrospermopsin. Mutation Research/DNA Repair, 472: 155-161. Carmichael, W.W. Status Report on Planktonic Cyanobacteria (Blue Green Algae) and their Toxins. EPA/600/R-92/079, (1992) , Cincinnati, Ohio; USEPA. Beasley, V. R., Haschek-Hock, W. M., Carmichael, W. W., Cook, W. D., Dahlem, A. M., Hooser, S. B., Lovell, R. A., Schaeffer, D. J., Thorn, P. M. and Valentine, W. M. (1990) Pathophysiology and toxicokinetic studies of bleu-green algae intoxication in the swine model. Annual report to the U.S. Army Medical research and Development Command, Fort Detrick, Frederick, Maryland. 21702-5102. Runnegar, M. T., Jackson, A. R. B. and Falconer, I. R. Toxicity to mice and sheep of a bloom of the Cyanobacterium (blue-green alga) Anabaena circinalis. Toxicon, (1988) 26: 599-602. Osborne, N. J., Webb, P. M., Shaw, G. R. (2001) The toxins of Lyngbya majuscule and their human and ecological health effects. Environ. Int. 27 : 381-392. Grobbelaar, J. U., Botes, E., Van den Heever, J. A., Botha, A-M. and Oberholster, P. J. (2004) Toxin production by cyanobacteria. Scope and Dynamics of toxin produced by cyanophytes in the freshwaters of South Africa and the human and other users. WRC Report no. 1029/1/04. ISBN No: 1- 77005-191-0. pp. 1-9. Ressom, R., Soong, F. S., Fritzgerald, J., Turczynowicz, L., El Saadi, O., Roder, D., Maynard, T. and Falconer, L. R. Health effects of toxic cyanobacteria (blue-green algae). National Health and Medical Research Council. Looking Glass Press, Australian Govt. Pub. Service, Canberra, Australia, (1994) ,ISBN 0-644-32908-4, pp. 108 MacKintosh, C., Beattie, K. A., Klumpp, S., Cohen, P. and Codd, G. A. Cyanobacterial microcystin-LR is a potent and specific inhitor of protein phosphatases 1 and 2 A from both mammals and higher plants. FEBS Lett, (1990) 264: 187-192. H. Saadatnia, H. Riahi, Cyanobacteria from paddy fields in Iran as a biofertilizer in rice plants, PLANT SOIL ENVIRON., 55, 2009 (5): 207–212.

Source of support: Nil, Conflict of interest: None Declared

Page 57