Cyanobacteria (Cyanophyta, Cyanoprocaryota, Cyanobacteria) (blue-green algae) are procaryotic phototrophic microorganisms playing an important ecological role in the freshwater and marine environment as primary producers. However, as a consequence of water eutrophication observed in many reservoirs in different parts of the world, these microorganisms form massive scums, known as water blooms, releasing cyanotoxins hazardous to fish and other aquatic organisms. Cyanotoxins are cyanobacterial secondary metabolites of various chemical structures harmful to humans, terrestial and aquatic animals such as fish. The most abundant cyanotoxins are microcystins and hepatotoxins inducing toxic changes in fish liver, kidney, gills, digestive tract and immune system. Very little is known on the effects of alkaloid neurotoxic anatoxin-a on fish and their immunity. The aim of this study was to assess the in vitro influence of anatoxin-a on immune cells isolated from the common carp (Cyprinus carpio L.). The leukocyte intracellular level of ATP was reduced only at the highest concentration of anatoxin-a. Apoptotic and necrotic leukocytes were observed at the lower and the highest concentrations of anatoxin-a, respectively. Elevated activity of caspases 3/7 after 2 hours and a concentration-dependent decrease in the proliferative ability of T and B lymphocytes was also observed. The results suggest that anatoxin-a could be a possible immunotoxic agent in the aquatic environment and may increase the susceptibility of fish to infectious and neoplastic diseases. Therefore, constant monitoring of anatoxin-a and its producers in lakes and fish ponds should be performed
Astrachan NB, Archer BG (1981) Simplified monitoring of anatoxin-a by reverse-phase high performance liquid chromatography and the sub-acute effects of anatoxin-a in rats. In: Carmichael WW (ed) The water environment: Algal toxins and health. Plenum Press, New York, N.Y.P., pp 437-446.
Ballot A, Krienitz L, Kotut K, Wiegand C, Pflugmacher S (2005) Cyanobacteria and cyanobacterial toxins in the alkaline crater lakes Sonachi and Simbi, Kenya. Harmful Algae 4: 139- 150.
Carmichael WW, Biggs DF, Gorham PR (1975) Toxicology and pharmacological action of anabaena flos-aquae toxin. Science 187: 542-544.
Carmichael WW, Falconer IR (1993) Diseases related to freshwater blue-green algal toxins, and control measures. In: Falconer IR (ed) Algal Toxins in Seafood and Drinking Water, New York, Academic Press, pp 187-209.
Caspi RR, Shahrabani R, Kehati-Dan T, Avtalion RR (1984) Heterogeneity of mitogen-responsive lymphocytes in carp (Cyprinus carpio). Dev Comp Immunol 8: 61-70.
Devlin JP, Edwards OE, Gorham PR, Hunter MR, Pike RK, Stavric B (1977) Anatoxin-a, a toxic alkaloid from Anabaena flos-aquae NCR-44h. Can J Chem 55: 1367-1371.
Edwards C, Beattie KA, Scrimgeour CM, Codd GA (1992) Identification of anatoxin-a in benthic cyanobacteria (blue-green algae) and in associated dog poisonings at Loch Insh, Scotland. Toxicon 30: 1165-1175.
Gugger M, Lenoir S, Berger C, Ledreux A, Druart JC, Humbert JF, Guette C, Bernard C (2005) First report in a river in France of the benthic cyanobacterium Phormidium favosum producing anatoxin-a associated with dog neurotoxicosis. Toxicon 45: 919-928.
Lakshmana Rao PV, Bhattacharya R, Gupta N, Parida MM, Bhaskar AS, Dubey R (2002) Involvement of caspase and reactive oxygen species in cyanobacterial toxin anatoxin-a-induced cytotoxicity and apoptosis in rat thymocytes and Vero cells. Arch Toxicol 76: 227-235.
Mosmann T (1983) Rapid colorimetric assay for cellular growth and survival: application to proliferation and cytotoxicity assays. J Immunol Methods 65: 55-63.
Namikoshi M, Murakami T, Watanabe MF, Oda T, Yamada J, Tsujimura S, Nagai H, Oishi S (2003) Simultaneous production of homoanatoxin-a, anatoxin-a, and a new non-toxic 4-hydroxyhomoanatoxin-a by the cyanobacterium Raphidiopsis mediterranea Skuja. Toxicon 42: 533-538.
Osswald J, Rellan S, Carvalho AP, Gago A, Vasconcelos V (2007) Acute effects of an anatoxin-a producing cyanobacterium on juvenile fish-Cyprinus carpio L. Toxicon 49: 693-698.
Park HD, Watanabe MF, Harada KI, Nagai H, Suzuki M, Watanabe M, Hayashi H (1993) Hepatotoxin (microcystin) and neurotoxin (anatoxin-a) contained in natural blooms and strains of cyanobacteria from Japanese freshwaters. Nat Toxins 1: 353-360.
Rapala J, Sivonen K, Luukkainen R, Niemela SI (1993) 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. J Appl Phycol 5: 581-591.
Spivak CE, Witkop B, Albuquerque EX (1980) Anatoxin-a: a novel, potent agonist at the nicotinic receptor. Mol Pharmacol 18: 384-394.
Tencalla F, Dietrich D (1997) Biochemical characterization of microcystin toxicity in rainbow trout (Oncorhynchus mykiss). Toxicon 35: 583-595.
Teneva I, Mladenov R, Popov N, Dzhambazov B (2005) Cytotoxicity and apoptotic effects of microcystin-LR and anatoxin-a in mouse lymphocytes. Folia Biol (Praha) 51: 62-67.
Viaggiu E, Melchiorre S, Volpi F, Di Corcia A, Mancini R, Garibaldi L, Crichigno G, Bruno M (2004) Anatoxin-a toxin in the cyanobacterium Planktothrix rubescens from a fishing pond in northern Italy. Environ Toxicol 19: 191-197.