Simultaneous production of homoanatoxin-a, anatoxin-a, and a new non-toxic 4-hydroxyhomoanatoxin-a by the cyanobacterium Raphidiopsis mediterranea Skuja.
A neurotoxin, homoanatoxin-a, was identified from a toxic strain of the cyanobacterium Raphidiopsis mediterranea Skuja (strain LBRI 48) isolated from Lake Biwa, Japan, as the major toxin component (0.57% of dry cell-weight). This cyanobacterium produced anatoxin-a and a new homoanatoxin-a derivative as minor components (0.04 and 0.06%, respectively). The structure of a new compound was assigned based on the spectral data as 4-hydroxyhomoanatoxin-a, which was not toxic to mice up to 2.0 mg/kg by intraperitoneal injection. The isolation of minor components was accomplished by improved extraction and separation procedures: (1) extraction with methanol-water (4:1) from dried cells, (2) adsorption of aqueous residue on ODS column (or cartridge) after evaporation of methanol, (3) cleaning up of the column by successive elution with water and 50% methanol/water, (4) elution of a toxic fraction by 20% methanol/water containing 0.1% TFA and (5) HPLC (ODS) purification with methanol/water containing 0.05% TFA. The procedures were effective in removing impurities and concentrating alkaloidal neurotoxins. It should be noted that this is the first report demonstrating the simultaneous production of anatoxin-a and homoanatoxin-a by the same strain of cyanobacterium.
Namikoshi
Michio
M
Department of Ocean Sciences, Tokyo University of Fisheries, Konan, Minato-ku, Tokyo 108-8477, Japan. namikosh@tokyo-u.fish.ac.jp
Murakami
Tomokazu
T
Watanabe
Mariyo F
MF
Oda
Taiko
T
Yamada
Junko
J
Tsujimura
Shigeo
S
Nagai
Hiroshi
H
Oishi
Shinshi
S
D000818:Animals; D001427:Bacterial Toxins / Q000096:biosynthesis* / Q000737:chemistry / Q000302:isolation & purification / Q000633:toxicity*; D019086:Bridged Bicyclo Compounds, Heterocyclic; D002457:Cell Extracts; D000458:Cyanobacteria / Q000737:chemistry*; D000087522:Cyanobacteria Toxins; D007274:Injections, Intraperitoneal; D007928:Lethal Dose 50; D008297:Male; D008387:Marine Toxins / Q000096:biosynthesis* / Q000737:chemistry / Q000302:isolation & purification / Q000633:toxicity*; D051379:Mice; D008813:Mice, Inbred ICR; D052998:Microcystins; D015394:Molecular Structure; D009498:Neurotoxins / Q000096:biosynthesis* / Q000737:chemistry / Q000302:isolation & purification; D014326:Tropanes
C482099:4-hydroxyhomoanatoxin-a; D001427:Bacterial Toxins; D019086:Bridged Bicyclo Compounds, Heterocyclic; D002457:Cell Extracts; D000087522:Cyanobacteria Toxins; D008387:Marine Toxins; D052998:Microcystins; D009498:Neurotoxins; D014326:Tropanes; C524097:homoanatoxin-a; C509783:anatoxin a