阴离子表面活性剂LAS对产毒和无毒微囊藻生长及产毒特性的影响

ANIONIC SURFACTANT LAS ON THE GROWTH AND TOXICITY OF TOXIC AND NON-TOXIC MICROCYSTIS

  • 摘要: 文章研究了低浓度范围内不同浓度梯度的阴离子表面活性剂直链烷基苯磺酸盐(LAS)对产毒微囊藻(Microcystis aeruginosa, FACHB905)和无毒微囊藻(Microcystis wesenbergii, FACHB908)生长、光合特性、种间竞争及毒素合成的影响。结果表明, 在0.05—5.0 mg/L LAS浓度梯度处理下, 产毒微囊藻的生物量、产毒基因mcyD表达量和每细胞MCs含量均在培养12d后显著增加。产毒微囊藻胞内和胞外MCs含量在各LAS浓度处理后分别为0.069、0.052、0.061、0.038和0.037 fg/fg Chl.a及107.1、103.7、127.1、99.6和113.7 ng/L。即使在0.5 mg/L低浓度LAS处理条件下, 上述3个参数也分别比对照组显著增加了24.2%、12.4倍和10.4%。浓度为0—0.2 mg/L LAS对无毒微囊藻的生物量无明显影响, 而较高浓度的LAS(0.5—5.0 mg/L)明显抑制了无毒微囊藻的生长。在两株微囊藻混合培养时, 0.2—1.0 mg/L LAS处理组的产毒铜绿微囊藻mcyD的表达对LAS响应迅速, 使得产毒微囊藻占总微囊藻的比例高达60%—80%, 明显高于对照组。但其MCs合成和释放速度缓慢, 在混合培养12d后才开始大量合成并释放微囊藻毒素, 此时胞内MCs含量分别为0.098、0.184、0.201、0.216、0.168和0.241 fg/fg Chl.a。总体上, 研究表明LAS对产毒微囊藻的生长和毒素合成具有促进作用, 因此, 在富营养化水体中LAS污染对产毒微囊藻优势的形成及水华综合毒性的潜在影响不可忽视。

     

    Abstract: Microcystis blooms are common in eutrophic water bodies in China. Some Microcystis species can produce microcystins (MCS), which pose a serious threat to the safety of humans and ecosystems. The anionic surfactant linear alkylbenzene sulfonate (LAS), as a kind of widespread organic pollutant in eutrophic water bodies, its potential effects on the succession of toxic and non-toxic Microcystis and its influence on the toxicity of toxic Microcystis are often ignored. The effects of different LAS concentrations (0, 0.05, 0.2, 0.5, 1.0 and 5.0 mg/L) on the growth, photosynthetic characteristics, interspecific competition and toxin synthesis of toxic Microcystis aeruginosa and non-toxic Microcystis wesenbergii were studied in the present study. The results showed that the biomass, mcyD expression and MCs content of the toxic Microcystis increased significantly after 12 days of culture at 0.05—5.0 mg/L LAS. The concentrations of intracellular and extracellular MCs in toxic Microcystis were 0.069, 0.052, 0.061, 0.038, 0.037 fg/fg chl.a and 107.1, 103.7, 127.1, 99.6 and 113.7 ng/L, respectively. 0—0.2 mg/L LAS had no significant effect on the biomass of Microcystis wesenbergii, while a higher concentration of LAS (0.5—5.0 mg/L) significantly inhibited the growth of non-toxic Microcystis wesenbergii. When two Microcystis strains were co-cultured, the expression of mcyD in Microcystis aeruginosa responded quickly to LAS, the proportion of toxic Microcystis aeruginosa in the total Microcystis up to 60%—80%. But the synthesis and release of MCs were slow. A large number of MCs were synthesized and released after 12 days of co-culture. The intracellular MCs content was 0.098, 0.184, 0.201, 0.216, 0.168 and 0.241 fg/fg chl.a, respectively. In general, this research showed that LAS could promote the growth and toxin synthesis of toxic Microcystis. Therefore, the potential role of LAS pollution on the dominance formation of toxic Microcystis and toxin of blooms in eutrophic water can not be ignored.

     

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