Study of the toxicity of Microcystis (blue-green algae) occurred in Lake Kasumigaura.

1.微囊藻平板培养方法的建立将铜绿微囊藻（Microcystisaeruginosa）K3 A的稀释样品接种于琼脂或琼脂糖固化的B12培养基上，在琼脂培养基上能形成菌落，而在琼脂培养基上不能形成菌落。琼脂糖的最适浓度为0.4%，倾注平板法和涂布法的菌落形成数无差异。2.霞浦湖微囊藻无菌菌株的分离采用平板培养和液体培养相结合的方法进行无菌菌株的分离。15株微囊藻经反复分离3次后，其中5株为无菌。3.毒性采用小鼠腹腔注射法对20株微囊藻进行了毒性试验。2株，M.铜绿假单胞菌K-70（LD_（50））> 250 mg/kg小鼠体重;铜绿假单胞菌K-139（LD_（50）：7.3mg/Kg）对小鼠有毒性。用K-139细胞裂解液处理小鼠，显微镜下可见肝脏明显充血、坏死。4.溶血与治疗K-139细胞粗毒素对小鼠、羊、马、兔的红细胞无溶血作用。K-139细胞的Novovicin处理（治愈）不影响毒素产生。

1.Development of plate culture method for Microcystis species.When the diluted samples of Microcystis aeruginosa K3A were plated on B12 medium solidfied with agar or agarose, the colonies were occurred on agarose medium but not on agar medium. The most optimum concentration of agarose was 0.4 % and there was no difference of CFU between a pour plate and spreading teckniques.2.Isolation of axenic strains of Microcystis species from Lake Kasumigaura.An isolation of axenic strains was accomplished by a combination of plate and liquid culture. After an isolation procedure was repeated 3 times, five strains among 15 strains were axenic.3.ToxicityThe toxicity of 20 isolates of Microcystis was examined by intraperitoneal injection in mice. Two strains, M. aeruginosa K-70 (LD50:> 250mg/Kg-mouse weight) and M. aeruginosa k-139(LD50:7.3mg/Kg), were toxic. Microscopic observations of the dead mice receiving the K-139 disrupted cells showed that there were marked congestion and necrosis of the liver.4.Hemolysis and curingCrude toxin extracted from K-139 cells did not caused the hemolysis of erythrocytes of mouse, sheep, horse and rabbit. The novovicin treatment (curing) of K-139 cells did not influence a toxin production.