Shimane University, Matsue, Japan.
Arch Environ Contam Toxicol. 2011 Jan;60(1):44-56. doi: 10.1007/s00244-010-9531-4. Epub 2010 Apr 27.
Due to the high importance of biofilms on river ecosystems, assessment of pesticides' adverse effects is necessary but is impaired by high variability and poor reproducibility of both natural biofilms and those developed in the laboratory. We constructed a model biofilm to evaluate the effects of pesticides, consisting in cultured microbial strains, Pedobacter sp. 7-11, Aquaspirillum sp. T-5, Stenotrophomonas sp. 3-7, Achnanthes minutissima N71, Nitzschia palea N489, and/or Cyclotella meneghiniana N803. Microbial cell numbers, esterase activity, chlorophyll-a content, and the community structure of the model biofilm were examined and found to be useful as biological factors for evaluating the pesticide effects. The model biofilm was formed through the cooperative interaction of bacteria and diatoms, and a preliminary experiment using the herbicide atrazine, which inhibits diatom growth, indicated that the adverse effect on diatoms inhibited indirectly the bacterial growth and activity and, thus, the formation of the model biofilm. Toxicological tests using model biofilms could be useful for evaluating the pesticide effects and complementary to studies on actual river biofilms.
由于生物膜对河流生态系统具有重要影响，因此评估农药的不良影响是必要的，但由于自然生物膜和实验室中培养的生物膜的高度变异性和重现性较差，这一评估受到了阻碍。我们构建了一个模型生物膜来评估农药的影响，该模型由培养的微生物菌株组成，包括 Pedobacter sp. 7-11、Aquaspirillum sp. T-5、 Stenotrophomonas sp. 3-7、Achnanthes minutissima N71、Nitzschia palea N489 和/或 Cyclotella meneghiniana N803。我们检测了模型生物膜中的微生物细胞数量、酯酶活性、叶绿素-a 含量和群落结构，发现这些指标可用作评估农药影响的生物因素。该模型生物膜是通过细菌和硅藻的协同相互作用形成的，使用抑制硅藻生长的除草剂莠去津进行的初步实验表明，莠去津对硅藻的不良影响间接抑制了细菌的生长和活性，从而抑制了模型生物膜的形成。使用模型生物膜进行毒理学测试可能有助于评估农药的影响，并与实际河流生物膜的研究互补。
