CYANOBACTERIAL TOXINS - Cyanobacteria - page 561

aquae , A . scheremetievi and Aph . fl os - aquae (Vasconcelos, 1994). The predominance of hepatotoxic
water blooms known to produce diverse MCs (MC-LR, MC-RR and MC-YR and others) is shown
to be associated with the dominance of M . aeruginosa in Portuguese freshwater bodies such as lakes,
reservoirs and rivers (Vasconcelos et al ., 1996, 2001; Vasconcelos and Pereira, 2001). Vasconcelos (1999)
reviewed the status of cyanobacterial toxins in Portugal and indicated the possible accumulation
of MC-LR by edible molluscs, fi shes, crayfi shes and mussels and risk to human beings upon
consumption. Blooms of M . aeruginosa and Aph . fl os-aquae from Lake Grand-Lieu (Vezie et al ., 1998)
and Saint-Caprais reservoir (Maatouk et al ., 2002) respectively, have been reported from France.
The development of blooms of M . aeruginosa in Belgium near Liege in three adjacent ponds led
to the death of birds (Wirsing et al ., 1998). Certain of the toxic cyanobacteria such as Oscillatoria ,
Phormidium and Planktothrix never form scums but the formation of dense mats of Oscillatoria and
Phormidium in oligotrophic, alpine waters of Switzerland with hepatotoxic and neurotoxic effects
have been reported (Mez et al ., 1997). The occurrence of HABs of Planktothrix , Microcystis , Anabaena
and Aphanizomenon , known producers of MCs and anatoxin-a, have been detected in many of the
water bodies in Germany (Hummert et al ., 2001; Wiedner et al ., 2001). Czech recreational and drinking
water bodies supported the development of HABs containing Microcystis spp., P . agardhii and Aph .
fl os - aquae that produced MCs (Marsalek et al ., 2001). Three eutrophic Latvian lakes (Lakes Mazais,
Lielais Balterzers and Sekitis) suffered the development of toxic M . aeruginosa , Aph . fl os - aquae and
Anabaena fl os - aquae resulting in the deterioration of water quality (Eynard et al ., 2000). Likewise, in
northeastern Slovene freshwaters the occurrence of M . aeruginosa blooms producing MCs has been
reported (Sedmak and Kosi, 1997). In Scotland, Lake Loch Leven developed hepatotoxic blooms of
M . aeruginosa and A . fl os - aquae persistently year after year leading to the death of several hundreds
of fi sh that accumulated on the shores (Codd et al ., 1995). The death of sheep and dogs and reports
of human illness due to toxic blooms of Microcystis in various water bodies of UK have come to
light (Dow and Swoboda, 2000; WHO, 2003). The severity of the bloom of Aph . fl os-aquae in a lake
of Surrey is depicted in Fig. 26. Northwest Atlantic, Orkney Islands, east coast of Scotland and the
North and Baltic Sea developed HABs of No. spumigena . However, coastal zones supported the
development other toxic cyanobcterial communities that infl uenced the toxin profi les and toxicity
(Dahlmann et al ., 2005). Halinen et al . (2007) provided evidence for the occurrence of late summer
blooms of No . spumigena and Aph . fl os - aquae in the Baltic Sea. Toxic strains isolated from open-sea
sampling stations and coastal Gulf of Finland revealed great genetic heterogeneity based on the
sequencing of 16S rRNA. The blooms supported the production of many MC variants, i.e. MC-LR,
[D-Asp 3 ] MC-LR, [D-Asp 3 ] MC-HtyR,, MC-HtyR, [D-Asp 3 , Dha 7 ] MC-HtyR and [Dha 7 ] MC-HtyR
(Halinen et al. 2007). A quantitative real-time PCR was applied to 120 samples from the Baltic Sea to
amplify ndaF gene that encodes subunit F of nodularin synthetase of No . spumigena . The distribution
of the cyanobacterium was found horizontally as well as vertically extending up to a depth of 30 m.
The frequency distribution refl ected by 30 ndaF gene copies ml -1 corresponding to 1-3 pg nodularin
ml -1 water (Koskenniemi et al ., 2007).
Studies conducted in Sweden (over a period of six years from 1991 to 1997) revealed the
development of HABs of M . aeruginosa , M . viridis and P . prolifi ca (Willen et al ., 2000). The development
of intoxication in pets and in 121 human beings due to P . agardhii bloom by the production of MCs
has been reported (WHO, 2003). HABs of species of Anabaena , Microcystis and Oscillatoria producing
MCs have been recorded from Norwich water bodies (Utkilen et al ., 2001). Majority of the water
bodies of Denmark also supported extensive development of HABs comprising of MC producers
i.e., Microcystis spp., Anabaena spp., P . agardhii and Aph . fl os - aquae (Henriksen, 2001). Hepatotoxic