[Biological safety of Aspergillus fumigatus SL-30 to non-target organisms].

OBJECTIVE: To evaluate biological safety of Aspergillus fumigatus SL-30, a potential molluscicide, to non-target organisms. METHODS: A. fumigatus SL-30 spores were scattered in the water (200 ml) from Yangtze River, lake, rain and tap water to forming 6 x 10(6) cfu/ml, the number of spores were then determined and recorded every 2 days. Effect of A. fumigatus SL-30 spores with concentration ranging from 10(4) cfu/ml to 10(6) cfu/ml on Brachydanio rerio, Macrobrachium nippoensis and tadpoles of Rana limnochris was tested by standard laboratory procedure, and survival rate of the above animals in 30 days was recorded. The tests included acute oral toxicity in mice, acute dermal toxicity and acute inhalation toxicity in rats. RESULTS: Spores of A. fumigatus SL-30 can survive for about 12 days in each water samples. Under the spore concentration of 10(4) cfu/ml, 10(5) cfu/ml and 10(6) cfu/ml, there was no significant dose-dependent relationship between spore concentration and survival rate of experiment animals. No significant difference in survival rate was found between the three kinds of aquatic organisms treated with A. fumigatus SL-30 and de-chlorinous water (P > 0.05). According to the experiment results of acute oral toxicity, acute dermal toxicity and acute inhalation toxicity, the acute toxicity of A. fumigatus SL-30 on animal was low. And the animals in experiment group did not show any obvious poisoning symptoms, anatomical abnormalities and pathologic change of the tissues. CONCLUSION: Aspergillus fumigatus SL-30 is comparatively safe to environment and tested non-target organisms.

[Biological safety of the molluscicidal ingredient from Aspergillus fumigatus SL-30 isolated from rhizosphere of Phytolacca acinosa].

OBJECTIVE: To study biological safety of the molluscicidal ingredient (MI, a kind of diketopiperazines) in the exocellular broth of Aspergillus fumigatus SL-30' which was isolated from the rhizosphere of Phytolacca acinosa. METHODS: The MI was prepared in concentrations ranging from 0.01 to 0.60 mg/L, at the same time molluscicidal activity against Oncomelannia hupensis was tested by using immersion method, and the LC50 in the case of immersion time for 24, 48 and 72 h was calculated. Acute toxicity of the MI with concentration ranging from 0.5 to 4.0 mg/L on Brachydanio rerio, Macrobrachium nippoensis and Rana limnochris was performed by standard laboratory procedure, and mortality rate of the tested animals with treated time of 24, 48 and 72 h was recorded. Effect of the MI on Eisenia fetida was tested using natural soil procedure with the dose of 1 and 10 mg/kg, and the poisoning performance and mortality in the 7th day and 14th day were recorded. Inhibition of the MI at 10 mg/kg on respiration of soil microorganisms was determined by sealed alkaline direct absorption method, and the released amount of CO2 (mg/100 g) in the 2nd, 5th, 7th, 10th, 12th and 15th day was determined. RESULTS: Molluscicidal activity of the MI against Oncomelania hupensis was shown with LC50 0.101, 0.062, and 0.022 mg/L in 24, 48 and 72 h, respectively. Mortality rate of Brachydanio rerio, Macrobrachium nippoensis and Rana limnochris all increased with the increase of MI concentration, and the LC50 of each kind of tested animals was recorded as follows: 1.941, 1.755 and 1.219 mg/L for Brachydanio rerio, 3.170, 2.720 and 2.419 mg/L for Macrobrachium nippoensis, 2.109, 1.751 and 1288 mg/L for Rana limnochris in 24, 48 and 72 h, respectively. The LC50 of MI on Eisenia fetida was >10.0 mg/kg. The inhibition rate of MI was less than 50% with a concentration of 10 mg/kg in 15 days. CONCLUSION: The MI shows molluscicidal activity on Oncomelania hupensis with much lower toxicity on Brachydanio rerio, Macrobrachium nippoensis and Rana limnochrisn. The MI is safe to non-target aquatic organisms, and to both Eisenia fetida and soil microorganisms under the effective mollussicidal concentration.

Purification, characterization and antitumor activity of polysaccharides extracted from Phellinus igniarius mycelia.

Water-soluble intracellular polysaccharides (IPS) were extracted from cultured mycelia of Phellinus igniarius. The IPS were purified by ethanol fractional precipitation, ion-exchange and size exclusion chromatography in that order. Homogeneous polysaccharide IPSW-1, IPSW-2, IPSW-3, and IPSW-4 were obtained, which molecular characteristics were examined using multiangle laser-light scattering and refractive index detector system. The average molecular weights of them were 34.1, 17.7, 15.1, 21.7kDa, respectively. GC analysis indicated that IPSW-1, IPSW-2 and IPSW-3 all only contained glucose, while IPSW-4 was composed of rhamnose, xylose, mannose, glucose and galactose in a molar ratio of 1.29:1.21:1:43.86:1.86. UV and IR analysis suggested they belonged to α-type of the pyran group and didn't contain protein. These homogeneous polysaccharides could inhibit the growth of SW480 and HepG2 cells to a certain extent in a dose-dependent manner. So they could be beneficial for the further development of a natural carcinoma preventive agent and functional food.

Effects of AIBL on Oncomelania hupensis, the intermediate snail host of Schistosoma japonicum: an enzyme histochemical study.

OBJECTIVE: To explore the effect of AIBL on Oncomelania hupensis, the intermediate snail host of Schistosoma japonicum. METHODS: The enzyme histochemical profiles of cholinesterase, cytochrome oxidase, lactate dehydrogenase, nitric oxide synthase, and succinate dehydrogenase in the soft tissues of Oncomelania hupensis, the intermediate host snail of Schistosoma japonicum, were analyzed before and after treatment with the active ingredient of Buddleia lindleyana (AIBL), a potent and safe plant molluscicide. RESULTS: Treatment with AIBL induced a notable decrease in the activities of the five enzymes (P<0.01). CONCLUSIONS: The results indicate that AIBL impairs the activities of the enzymes, thereby influencing the transfer of neurotransmitter and energy supply in Oncomelania hupensis and ultimately harming their various physiological functions, which are considered to cause death of the species.