Jonasson Sara, Vintila Simina, Sivonen Kaarina, El-Shehawy Rehab
Department of Botany, Stockholm University, Stockholm, Sweden.
FEMS Microbiol Ecol. 2008 Jul;65(1):31-9. doi: 10.1111/j.1574-6941.2008.00499.x. Epub 2008 May 22.
Cyanobacterial blooms in the Baltic Sea are a common phenomenon and are formed by the heterocystous, filamentous species Nodularia spumigena. The toxicity of these blooms is attributed to the hepatotoxin nodularin, produced by N. spumigena. Little is known regarding the regulatory mechanisms or environmental signaling that control nodularin production. Here we report the characterization of the transcriptional expression pattern of the nodularin synthetase gene cluster (nda) during phosphate depletion, and nitrogen supplementation. Real-time PCR analysis of these genes revealed that while cells continuously expressed the nda cluster, the expression of all nda genes increased when cells were subjected to phosphate depletion, and decreased in the presence of ammonium. In contrast to the shifts in expression, the intracellular and extracellular nodularin concentrations did not vary significantly during the treatments.
波罗的海的蓝藻水华是一种常见现象，由具有异形胞的丝状物种泡沫节球藻（Nodularia spumigena）形成。这些水华的毒性归因于泡沫节球藻产生的肝毒素节球藻毒素。关于控制节球藻毒素产生的调控机制或环境信号知之甚少。在此，我们报告了节球藻毒素合成酶基因簇（nda）在磷酸盐耗尽和补充氮期间的转录表达模式特征。对这些基因的实时PCR分析表明，虽然细胞持续表达nda簇，但当细胞受到磷酸盐耗尽时，所有nda基因的表达增加，而在铵存在的情况下表达下降。与表达变化相反，在处理过程中细胞内和细胞外节球藻毒素浓度没有显著变化。
