Center for Environmental Biotechnology, University of Tennessee, Knoxville, Tennessee 37996, United States.
Environ Sci Technol. 2011 Mar 1;45(5):1962-9. doi: 10.1021/es103538b. Epub 2011 Jan 31.
Microcystis blooms occur worldwide and threaten aquatic ecosystems and human health. Sublethal effects on early developmental stages of fish are largely unknown, and research has mainly focused on microcystin toxins (such as MC-LR) rather than Microcystis cells. We exposed (96 h) zebrafish larvae to purified MC-LR (0-1000 μg/L) or lyophilized Microcystis aeruginosa containing 4.5 μg/L MC-LR and evaluated changes in global gene expression (Affymetrix GeneChip zebrafish genome arrays). Significant changes in gene expression (≥ 1.7-fold change, p < 0.0001) were determined with Rosetta Resolver 7.0, and ontology analysis was conducted with the DAVID bioinformatics tool. The number of differentially expressed genes relative to control increased with MC-LR concentration and included genes related to known mechanisms of action for MC-LR in mammals and older life stages of fish, as well as genes unique to larval zebrafish. Up-regulation of vitellogenin genes (vtg) (19.2-fold to >100-fold on arrays; 619.3-fold confirmed by quantitative PCR) was observed in Microcystis-exposed larvae but not in larvae exposed to MC-LR. Up-regulation of vtg indicates exposure to estrogenic substance(s) and suggests that Microcystis may be a natural source of environmental estrogens. Concerns about effects of Microcystis blooms may extend beyond those associated with the microcystin toxin.
微囊藻水华在全球范围内发生，威胁着水生生态系统和人类健康。鱼类早期发育阶段的亚致死效应在很大程度上尚不清楚，而且研究主要集中在微囊藻毒素（如 MC-LR）上，而不是微囊藻细胞上。我们将斑马鱼幼虫暴露于纯化的 MC-LR（0-1000 μg/L）或含有 4.5 μg/L MC-LR 的冻干铜绿微囊藻中（96 h），并评估了全基因组表达的变化（Affymetrix GeneChip 斑马鱼基因组芯片）。使用 Rosetta Resolver 7.0 确定了基因表达的显著变化（≥ 1.7 倍变化，p < 0.0001），并使用 DAVID 生物信息学工具进行了本体分析。与对照相比，MC-LR 浓度下差异表达基因的数量增加，包括与哺乳动物和鱼类较老生活阶段的 MC-LR 已知作用机制相关的基因，以及仅在斑马鱼幼虫中存在的基因。在暴露于微囊藻的幼虫中观察到卵黄蛋白原基因（vtg）的上调（芯片上的 19.2 倍至>100 倍；定量 PCR 证实的 619.3 倍），而在暴露于 MC-LR 的幼虫中则没有。vtg 的上调表明暴露于雌激素物质，这表明微囊藻可能是环境雌激素的天然来源。对微囊藻水华影响的担忧可能不仅限于与微囊藻毒素相关的影响。
