菌液状态对青海弧菌Q67急性生物毒性测试的影响

The influence of the state of bacterium suspension on the acute toxicity test using fresh luminescent bacterium Vibrio Qinghaiensis sp.-Q67

为了研究菌液状态对发光细菌急性毒性测试结果重现性的影响,实验选取ZnSO4·7H2O、CdCl2·2.5H2O、三氯异氰尿酸、十二烷基苯磺酸钠四种化学物质对不同状态的青海弧菌(Vibrio Qinghaiensis sp.-Q67)菌悬液进行急性毒性测试.结果表明:利用储存时间不同的菌种培养8.5 h或储存时间相同的菌种分别培养8.5 h、9.0 h、10.0 h获得的Q67菌悬液进行急性生物毒性测试,结果差异均较大.为了进一步探讨其中的原因,对实验所用菌悬液的pH、相对发光值(RLU)、OD600值(菌液密度指标)进行检测发现:菌液的pH差异不大,发光值和OD600值存在较大的不同.因此,发光值和OD600值是影响实验重现性的主要因素,而菌液的OD600值影响其发光值.因此,严格控制试验菌液的OD600值对提高实验的重现性具有重要意义.

ZnSO4·7H2O, CdCl2·2.5H2O, trichloroisocyanuric acid and sodium dodecyl benzene sulfonate were selected to detect the impact about the state of bacterium suspension on the reproducibility of acute toxicity tests with luminescent bacterium Vibrio Qing- haiensis sp.-Q67 as test bacterium. The great variations of the toxicity of the four chemicals on Q67 were observed, using either the bacterium suspension which was cultivated for 8.5 h with different storage time of strains or the same storage time of strains which was cultivated for 8.5,9.0 and 10 hrs respectively. The parameters of Q67 suspension, such as pH, relative light unit （RLU） and bacterial density （OD600）, were detected to discuss the reasons of the great variations obtained in the results. It showed that there was slight distinction in the pH of bacterium suspension at different growth stage but significant changes of the OD600 value and RLU value which showed their significant influence on the reproducibility of the tests. Since the OD600 could affect the RLU value of bacterium suspension, it is necessary to identify the OD600 of Q67 bacterium suspension in order to obtain the good reproducibil- ity of acute toxicity test.