Toxicology of a Microcystis ichthyoblabe waterbloom from Lake Oued Mellah (Morocco).
In the Lake Oued Mellah cyanobacteria waterblooms occur periodically in late spring and summer with Microcystis ichthyoblabe as the main bloom-forming species. In 1999, a heavy waterbloom of M. ichthyoblabe occurred during May June with a maximal biomass of 298 mg/l. During this period, several bloom samples were collected. The toxicity assessment was done by mouse and brine shrimp (Artemia) bioassays. Apart from the sample collected on 15/06/1999, all the other samples were toxic by mouse bioassay. The LD50 determined by intraperitoneal injection to mice during active cyanobacterial growth and decline phases were 518 and 1924 mgDW/kg respectively. Using Artemia bioassay, the 24hLC50 varied from 6.0 to 40.6 mg/ml and the 48hLC50 ranged from 2.8 to 18.2 mg/ml. The separation and identification of microcystin variants was performed by high performance liquid chromatography-photodiode array detection. Eleven toxins were separated and preliminarily identified as microcystin variants as they exhibit a typical UV spectra like the microcystin-LR standard. The quantification of total microcystins determined by enzyme-linked immunosorbent assay showed that the contents were varied between 0.1 and 0.76 microgram/g DW.
Sabour
Brahim
B
Faculté des Sciences et Techniques Mohammedia, Département de Biologie, Mohammedia, Morocco.
Loudiki
Mohammed
M
Oudra
Brahim
B
Vasconcelos
Vitor
V
Martins
Rosario
R
Oubraim
Said
S
Fawzi
Brahim
B
D000818:Animals; D001156:Artemia; D002851:Chromatography, High Pressure Liquid; D004791:Enzyme Inhibitors / Q000302:isolation & purification / Q000633:toxicity*; D005068:Eutrophication; D007928:Lethal Dose 50; D008297:Male; D008387:Marine Toxins; D051379:Mice; D052998:Microcystins; D046931:Microcystis; D010456:Peptides, Cyclic / Q000302:isolation & purification / Q000633:toxicity*
D004791:Enzyme Inhibitors; D008387:Marine Toxins; D052998:Microcystins; D010456:Peptides, Cyclic; C057862:cyanoginosin LR