Karenia mikimotoi （Miyake ＆ Kominami ex Oda） Hansen ＆ Moestrup is associated with harmful algal blooms in temperate and subtropical zones of the world. The hemolytic substances produced by K. mikimotoi are thought...Karenia mikimotoi （Miyake ＆ Kominami ex Oda） Hansen ＆ Moestrup is associated with harmful algal blooms in temperate and subtropical zones of the world. The hemolytic substances produced by K. mikimotoi are thought to cause mortality in fishes and invertebrates. We evaluated the composition of the hemolytic toxin produced by K. mikimotoi cultured in the laboratory using thin-layer chromatography. In addition, we evaluated the effect of co-occuring algae （Prorocentrum donghaiense and Alexandrium tamarense） and the cladoceran grazer Moina mongoliea on hemolytic toxin production in K. mikimotoi. The hemolytic toxins from K. mikimotoi were a mixture of 2 liposaccharides and 1 lipid. Waterborne clues from P. donghaiense and A. tamarense inhibited the growth of K. mikimotoi but increased the production of hemolytic toxins. Conversely, K. mikimotoi strongly inhibited the growth of caged P. donghaiense and A. tamarense. In addition, the ingestion of K. mikimotoi by M. mongolica induced the production of hemolytic toxins in K. mikimotoi. Taken together, our results suggest that the presence of other microalgae and grazers may be as important as environmental factors for controlling the production of hemolytic substances. K. mikimotoi secreted allelochemicals other than unstable fatty acids with hemolytic activity. The production of hemolytic toxins in dinofiagellates was not only dependent on resource availability, but also on the risk of predation. Hemolytic toxins likely play an important role as chemical deterrents secreted by K. mikimotoi.展开更多
Aflatoxins are produced mainly by Aspergillus flavus and Aspergillus parasiticus, and can be found in many grains such as peanuts, soybeans and com. This study aimed to qualitatively and quantitatively evaluate the pr...Aflatoxins are produced mainly by Aspergillus flavus and Aspergillus parasiticus, and can be found in many grains such as peanuts, soybeans and com. This study aimed to qualitatively and quantitatively evaluate the production of aflatoxin in liquid media using strains of Aspergillus flavus obtained from peanuts marketed in the city of Fortaleza, CEo Strains of Aspergillus flavus were inoculated into a liquid medium malt extract and after 2 days inoculated into a second medium containing sucrose 5%, MgSO4·7H20 0.1%, KH2PO4 1%, ZnSO4·7H2O 0.0176 g, and cultured for 3 more days. The media were kept at room temperature ranging from 24°C to 32 °C with agitation of 130 rpm and aeration of 4.17 Llmin. Qualitative analysis was performed by thin layer chromatography and quantitatively by high performance liquid chromatography with fluorescence detection, demonstrating the production of aflatoxin B I （588 mg/L） and B2 （929 mg/L）.展开更多
本文报告用多聚酶链反应检测产生不耐热肠毒素大肠杆菌,使用二个寡核苷酸引物,直接从麦康凯平板的菌落中对该毒素的 A 亚基一段高度保守区域的 DNA 进行扩增,经琼脂糖凝胶电泳检测,30株细菌只有产生不耐热肠毒素大肠杆菌检测结果为阳性...本文报告用多聚酶链反应检测产生不耐热肠毒素大肠杆菌,使用二个寡核苷酸引物,直接从麦康凯平板的菌落中对该毒素的 A 亚基一段高度保守区域的 DNA 进行扩增,经琼脂糖凝胶电泳检测,30株细菌只有产生不耐热肠毒素大肠杆菌检测结果为阳性,其它细菌均为阴性.此法简便、特异、敏感.展开更多
基金financed by the Research Project of Jiangxi education department(Pro-ject No.GJJ09447)supported by Nanchang Key Laboratory of Biochemical Engineering(Nan-chang,China)
基金Supported by the National Natural Science Foundation of China(Nos.30970502,U0733006)the National Basic Research Program of China(973 Program)(No.2010CB428702)
文摘Karenia mikimotoi （Miyake ＆ Kominami ex Oda） Hansen ＆ Moestrup is associated with harmful algal blooms in temperate and subtropical zones of the world. The hemolytic substances produced by K. mikimotoi are thought to cause mortality in fishes and invertebrates. We evaluated the composition of the hemolytic toxin produced by K. mikimotoi cultured in the laboratory using thin-layer chromatography. In addition, we evaluated the effect of co-occuring algae （Prorocentrum donghaiense and Alexandrium tamarense） and the cladoceran grazer Moina mongoliea on hemolytic toxin production in K. mikimotoi. The hemolytic toxins from K. mikimotoi were a mixture of 2 liposaccharides and 1 lipid. Waterborne clues from P. donghaiense and A. tamarense inhibited the growth of K. mikimotoi but increased the production of hemolytic toxins. Conversely, K. mikimotoi strongly inhibited the growth of caged P. donghaiense and A. tamarense. In addition, the ingestion of K. mikimotoi by M. mongolica induced the production of hemolytic toxins in K. mikimotoi. Taken together, our results suggest that the presence of other microalgae and grazers may be as important as environmental factors for controlling the production of hemolytic substances. K. mikimotoi secreted allelochemicals other than unstable fatty acids with hemolytic activity. The production of hemolytic toxins in dinofiagellates was not only dependent on resource availability, but also on the risk of predation. Hemolytic toxins likely play an important role as chemical deterrents secreted by K. mikimotoi.
文摘Aflatoxins are produced mainly by Aspergillus flavus and Aspergillus parasiticus, and can be found in many grains such as peanuts, soybeans and com. This study aimed to qualitatively and quantitatively evaluate the production of aflatoxin in liquid media using strains of Aspergillus flavus obtained from peanuts marketed in the city of Fortaleza, CEo Strains of Aspergillus flavus were inoculated into a liquid medium malt extract and after 2 days inoculated into a second medium containing sucrose 5%, MgSO4·7H20 0.1%, KH2PO4 1%, ZnSO4·7H2O 0.0176 g, and cultured for 3 more days. The media were kept at room temperature ranging from 24°C to 32 °C with agitation of 130 rpm and aeration of 4.17 Llmin. Qualitative analysis was performed by thin layer chromatography and quantitatively by high performance liquid chromatography with fluorescence detection, demonstrating the production of aflatoxin B I （588 mg/L） and B2 （929 mg/L）.
