Department of Biotechnology, College of Biological and Environmental Engineering, Zhejiang University of Technology, Hangzhou 310032, People's Republic of China.
Environ Toxicol. 2012 Mar;27(4):229-37. doi: 10.1002/tox.20636. Epub 2010 Aug 19.
Streptomycin is a common contaminant in a variety of industrial and agricultural wastewaters. The available information on the potential toxicity of streptomycin of fresh algae implicated in the treatment of biological wastewater is extremely limited. The objective of this study was to evaluate the effects of streptomycin on physiological indices and photosynthesis-related gene transcription. The results of short-term batch bioassays indicated that streptomycin was more sensitive to cyanobacteria than to green algae. The EC50 of streptomycin in Microcystis aeruginosa and Chlorella vulgaris were 0.28 and 20.08 mg L(-1) , respectively. These selected streptomycin concentrations inhibited algal cell growth and decreased chlorophyll or phycocyanobilin content. Streptomycin also destroyed the overall membrane system, which was speculated from malondialdehyde (MDA) content and electrolyte leakage increasing after streptomycin exposure. Two algae were induced to increase their antioxidant enzyme activities to withstand streptomycin. However, the balance between oxidant substance and antioxidant enzyme was broken, because reactive oxygen species (ROS) content simultaneously increased. Streptomycin inhibited photosynthesis-related gene transcription in C. vulgaris and M. aeruginosa. Transcript levels of psaB, psbA, and rbcL in C. vulgaris decreased to only 14.5%, 32.2%, and 9.3% of the control, respectively. Similarly, the transcript levels of psaB, psbD, and rbcL in M. aeruginosa decreased markedly in the present of streptomycin. The transcription of these genes was 12.4%, 26.1%, and 28.4% of the control after 0.1 mg L(-1) streptomycin exposure, respectively. Our results demonstrate that streptomycin is toxic to fresh algae, affects photosynthesis-related gene transcription, and blocks electron transport and ROS overproduction.
链霉素是各种工业和农业废水中的常见污染物。关于用于处理生物废水的新鲜藻类中链霉素的潜在毒性的可用信息极为有限。本研究的目的是评估链霉素对生理指标和光合作用相关基因转录的影响。短期批量生物测定的结果表明，链霉素对蓝藻的敏感性高于绿藻。在铜绿微囊藻和普通小球藻中，链霉素的 EC50分别为 0.28 和 20.08 mg/L。这些选定的链霉素浓度抑制藻类细胞生长，并降低叶绿素或藻蓝素含量。链霉素还破坏了整体膜系统，这可以从链霉素暴露后丙二醛（MDA）含量和电解质泄漏增加来推测。两种藻类被诱导增加其抗氧化酶活性以抵抗链霉素。然而，由于活性氧（ROS）含量同时增加，氧化物质和抗氧化酶之间的平衡被打破。链霉素抑制了 C. vulgaris 和 M. aeruginosa 中的光合作用相关基因转录。C. vulgaris 中 psaB、psbA 和 rbcL 的转录水平分别降至对照的 14.5%、32.2%和 9.3%。同样，在存在链霉素的情况下，M. aeruginosa 中 psaB、psbD 和 rbcL 的转录水平明显下降。在 0.1 mg/L 链霉素暴露后，这些基因的转录水平分别为对照的 12.4%、26.1%和 28.4%。我们的结果表明，链霉素对新鲜藻类有毒，影响光合作用相关基因转录，并阻断电子传递和 ROS 过量产生。
