Biology Reference
In-Depth Information
Figure 6:
Structure of MC-LR.
from
M
.
aeruginosa
(Botes
et al
., 1985) and
Anabaena
sp. strain 202A1 and 202A2 (Sivonen
et al
., 1992a).
[D-Asp
3
] MC-RR is produced by
O
.
agardhii
(Luukkainen
et al
., 1994),
Anabaena
sp. (Sivonen
et al
.,
1992a) and from the bloom samples of
P
.
rubescens
(Briand
et al
., 2005). [Dha
7
] MC-RR is produced
by
M
.
aeruginosa
,
O
.
agardhii
(Luukkainen
et al
., 1993) and
Anabaena
sp. (Sivonen
et al
., 1992a). The
bloom samples of
P
.
rubescens
showed the presence of [D-Asp
3
, Dhb
7
] MC-RR (Briand
et al
., 2005).
Dienhelt
et al
. (2006) reported the occurrence of [Asp
3
] MC-LA and [Asp
3
] MC-LL in
M
.
aeruginosa
strain B2666. Sivonen
et al
. (1992a) isolated and characterized MC-LR, [D-Asp
3
] MC-LR, [Dha
7
] MC-
LR, [D-Asp
3
, Dha
7
] MC-LR, MC-RR, [D-Asp
3
] MC-RR, [Dha
7
] MC-RR and [D-Asp
3
, Dha
7
] MC-RR
from seven freshwater strains of
Anabaena
spp.
Quantitative differences between toxins within and between strains were found and the
most abundant MCs found were either MC-LR or MC-RR or their demethyl derivatives in a
strain. Thirteen (two green- and the rest red-pigmented) strains of
O
.
agardhii
were analyzed for MC
content and the species of MCs. Each strain produced 2 to 5 variants of MC, i.e. [D-Asp
3
] MC-LR,
[Dha
7
] MC-LR, [D- Asp
3
, Dha
7
] MC-RR, [D-Asp
3
] MC-RR and [Dha
7
] MC-RR. Of these, [D-Asp
3
]
MC-RR was most frequently found up to 80-99% of total MC content in each of the nine strains.
However, [Dha
7
] MC-RR was the principal MC species in the rest of the four strains of which two
were red-pigmented (Luukkainen
et al
., 1993). Three new variants of MCs were also isolated but only
one could be identifi ed as [D-Asp
3
, Mser
7
] MC-RR that has N-methyl-serine in place of Mdha. Such
sustitution of N-methyl-serine has been described in
Microcystis
spp. as [Mser
7
] MC-LR (Namikoshi
et
al
., 1992c), in
Nostoc
sp. strain 152 as [ADM Adda
5
, Mser
7
] MC-LR (Sivonen
et al
., 1992b) and L-serine
variants in two
Anabaena
sp. strain 202 are [L-Ser
7
] MC-LR and [L-Ser
7
] MC-RR and in
Anabaena
sp.
strain 66 as [L-Ser
7
] MC-HtR (Namikoshi
et al
., 1992b).
The blooms of
Microcystis
and
Planktothrix
were predominantly represented in lakes of Belgium
and Luxemburg followed by those of
Anabaena
and
Woronichinia
and
Aphanizomenon
. Six variants
of MCs were present in most of the blooms where MC-LR was predominantly represented in 64%
of analyzed blooms, followed by MC-YR (55%). MC-LY has not been detected (Willame
et al
., 2005).
