Hóa chất độc 3 sinh tổng hợp và Các độc tố từ cyanobacteria là các chất chuyển hóa trung tổng hợp trong tế bào của một số loài từ ít nhất bốn trong năm đơn đặt hàng của các vi khuẩn cyanobacteria. Các độc tố hiện sự đa dạng tuyệt vời, khác nhau, từ alkaloids đơn giản đến phức tạp các hợp chất đa vòng và peptide cyclic. Trong tất cả các xác suất, các độc tố đặc trưng minh họa chỉ có một tỷ lệ nhỏ của tổng số các độc tố của vi khuẩn cyanobacteria, như hầu hết các. | 3 Toxin Chemistry and Biosynthesis The cyanobacterial toxins are secondary metabolites synthesized within the cells of some species from at least four of the five orders of cyanobacteria. The toxins show great diversity ranging from simple alkaloids to complex polycyclic compounds and cyclic peptides. In all probability the characterized toxins illustrate only a small proportion of the total toxins of cyanobacteria as most cyanobacterial species have not yet been examined for toxicity. The best-understood peptide toxin group the microcystins originally isolated from the genus Microcystis have more than 60 molecular variants identified at the present time. Similarly the saxitoxin-related alkaloids in cyanobacteria show a family of compounds of differing toxicity some of which are different from those of marine dinoflagellates Onodera Satake et al. 1997 . By comparison with toxins identified from marine dinoflagellates Baden and Trainer 1993 cyanobacteria have not yet been shown to possess polyether neurotoxins though there have been numerous reports of uncharacterized neurotoxicity from cyanobacteria Hawser Capone et al. 1991 Baker et al. 2001 . From the viewpoint of safety of drinking water supplies the major area of concern is the water-soluble cyanobacterial toxins. Lipid-soluble toxins are bound to cells or particulate fragments that will be removed by coagulation and sedimentation in standard water treatment see Chapter 12 . Lipid-soluble toxins are however of medical significance in food especially shellfish and fish exposed to dinoflagellate blooms and have caused widespread illness and death in human populations Falconer 1993 . They are also relevant in recreational exposure to the cyanobacteria. The best characterized example is Lyngbya majuscula in tropical coastal waters which causes severe skin burns to people bathing and fishing Banner 1959 . This benthic cyanobacterium which grows on rocks seagrass and marine macroalgae contains several tumor-promoting
