Microcystis aeruginosa is the dominant algae in most of the eutrophicated lakes in China. It can produce cyclic heptapeptides, known as microcystins, which can cause liver damage in wild and domestic animals. In this ...Microcystis aeruginosa is the dominant algae in most of the eutrophicated lakes in China. It can produce cyclic heptapeptides, known as microcystins, which can cause liver damage in wild and domestic animals. In this paper, a two-stage transformation assay for demonstrating the carcinogenic effects of the algal toxins is reported. The cell strain used in this assay was derived from embryos of Syrian golden hamster and the algal toxins were extracted from Microcystis aeruginosa, termed microcystis raw toxin (MRT). To elucidate its promoting activity, the target cells were first exposed to a low dosage of 3-mcthylcholanthrene (MCA) and then to MRT. The results showed that MRT significantly enhanced the MCA-initiated cell transformation, and a dose-response relatinnship was observed, but it failed to induce transformation of SHE cells not pretreated by MCA. These results suggest that the MRT play an important role in the malignant transformation of SHE cells. MRT may thus be a tumor promoter, and this transformation assay with SHE cells may be used to predict tumor prompting activity of environmental chemicals, before long-term in vivo two-stage carcinogenesis experiments are carried out.展开更多
The mutagenicity of diesel exhaust particles (DEP) was studied by using Salmonella typhimurium strains TA98 and TA100o in vitro and mice micronucleus in vivo test. DEP from six kinds of medium and heavy-duty diesel ve...The mutagenicity of diesel exhaust particles (DEP) was studied by using Salmonella typhimurium strains TA98 and TA100o in vitro and mice micronucleus in vivo test. DEP from six kinds of medium and heavy-duty diesel vehicles, which were made in China and imported, were tested. The vehicles were operated under free accelerating condition. The results showed that the DEP contained mutagenic activity. An increase in the number of the Salmonella TA98 was observed in the presence and especially in the absence of S9 mix. Positive results were also obtained from mice micronucleus assay. The frequency of mice bone marrow micronucleated polychromatic erythrocytes (M PCE) was increased and it showed a definite dose-response relationship. Comparing the different types of the vehicles,we found that the mutagenicity of DEP from domestic made vehicles was stronger than that from the imported ones展开更多
文摘Microcystis aeruginosa is the dominant algae in most of the eutrophicated lakes in China. It can produce cyclic heptapeptides, known as microcystins, which can cause liver damage in wild and domestic animals. In this paper, a two-stage transformation assay for demonstrating the carcinogenic effects of the algal toxins is reported. The cell strain used in this assay was derived from embryos of Syrian golden hamster and the algal toxins were extracted from Microcystis aeruginosa, termed microcystis raw toxin (MRT). To elucidate its promoting activity, the target cells were first exposed to a low dosage of 3-mcthylcholanthrene (MCA) and then to MRT. The results showed that MRT significantly enhanced the MCA-initiated cell transformation, and a dose-response relatinnship was observed, but it failed to induce transformation of SHE cells not pretreated by MCA. These results suggest that the MRT play an important role in the malignant transformation of SHE cells. MRT may thus be a tumor promoter, and this transformation assay with SHE cells may be used to predict tumor prompting activity of environmental chemicals, before long-term in vivo two-stage carcinogenesis experiments are carried out.
文摘The mutagenicity of diesel exhaust particles (DEP) was studied by using Salmonella typhimurium strains TA98 and TA100o in vitro and mice micronucleus in vivo test. DEP from six kinds of medium and heavy-duty diesel vehicles, which were made in China and imported, were tested. The vehicles were operated under free accelerating condition. The results showed that the DEP contained mutagenic activity. An increase in the number of the Salmonella TA98 was observed in the presence and especially in the absence of S9 mix. Positive results were also obtained from mice micronucleus assay. The frequency of mice bone marrow micronucleated polychromatic erythrocytes (M PCE) was increased and it showed a definite dose-response relationship. Comparing the different types of the vehicles,we found that the mutagenicity of DEP from domestic made vehicles was stronger than that from the imported ones
