School of Biotechnology and Biomolecular Sciences, University of New South Wales, NSW 2052, Australia.
Mol Cell Proteomics. 2011 Sep;10(9):M110.003749. doi: 10.1074/mcp.M110.003749. Epub 2011 May 24.
Toxin production in algal blooms presents a significant problem for the water industry. Of particular concern is microcystin, a potent hepatotoxin produced by the unicellular freshwater species Microcystis aeruginosa. In this study, the proteomes of six toxic and nontoxic strains of M. aeruginosa were analyzed to gain further knowledge in elucidating the role of microcystin production in this microorganism. This represents the first comparative proteomic study in a cyanobacterial species. A large diversity in the protein expression profiles of each strain was observed, with a significant proportion of the identified proteins appearing to be strain-specific. In total, 475 proteins were identified reproducibly and of these, 82 comprised the core proteome of M. aeruginosa. The expression of several hypothetical and unknown proteins, including four possible operons was confirmed. Surprisingly, no proteins were found to be produced only by toxic or nontoxic strains. Quantitative proteome analysis using the label-free normalized spectrum abundance factor approach revealed nine proteins that were differentially expressed between toxic and nontoxic strains. These proteins participate in carbon-nitrogen metabolism and redox balance maintenance and point to an involvement of the global nitrogen regulator NtcA in toxicity. In addition, the switching of a previously inactive toxin-producing strain to microcystin synthesis is reported.
藻华中的毒素产生对水产业构成了重大问题。特别令人关注的是微囊藻毒素，这是一种由单细胞淡水物种铜绿微囊藻产生的强效肝毒素。在这项研究中，分析了六种有毒和无毒的铜绿微囊藻菌株的蛋白质组，以进一步阐明微囊藻毒素产生在这种微生物中的作用。这代表了在蓝细菌物种中进行的首次比较蛋白质组学研究。观察到每个菌株的蛋白质表达谱存在很大的多样性，其中很大一部分鉴定出的蛋白质似乎是菌株特异性的。总共鉴定出 475 种可重复的蛋白质，其中 82 种构成铜绿微囊藻的核心蛋白质组。几个假设和未知蛋白的表达，包括四个可能的操纵子，得到了证实。令人惊讶的是，没有发现仅由有毒或无毒菌株产生的蛋白质。使用无标记归一化谱丰度因子方法进行的定量蛋白质组学分析揭示了在有毒和无毒菌株之间差异表达的 9 种蛋白质。这些蛋白质参与碳氮代谢和氧化还原平衡维持，并表明全球氮调节因子 NtcA 参与了毒性。此外，还报告了先前不活跃的产毒菌株向微囊藻毒素合成的转换。
