Geiss U, Vinnemeier J, Kunert A, Lindner I, Gemmer B, Lorenz M, Hagemann M, Schoor A
Institut für Okologie, Botanisches Institut, Ernst-Moritz-Arndt-Universität Greifswald, D-17487 Greifswald, Germany.
Appl Environ Microbiol. 2001 Nov;67(11):5247-53. doi: 10.1128/AEM.67.11.5247-5253.2001.
The use of isiA expression to monitor the iron status of cyanobacteria was investigated. Studies of laboratory cultures of the cyanobacterium Synechocystis sp. strain PCC 6803 showed that isiA expression is dependent on the organism's response to iron deficiency; isiA expression starts as soon as a decline in the rate of growth begins. isiA expression is switched on at concentrations of iron citrate of less than 0.7 microM. A PCR method was developed for the specific amplification of the iron-regulated isiA gene from a variety of cyanobacteria. After we developed degenerate primers, 15 new internal isiA fragments (840 bp) were amplified, cloned, and sequenced from strains obtained from algal collections, from new isolates, and from enriched field samples. Furthermore, isiA expression could be detected by means of reverse transcription-PCR when enriched field samples were exposed to restricted iron availability. These results imply that determining the level of iron-regulated isiA expression can serve to indicate iron deficiency in cyanobacterial samples of differing origins from the field.
研究了利用 isiA 表达来监测蓝藻铁状态的情况。对蓝藻聚球藻属 Synechocystis sp. 菌株 PCC 6803 的实验室培养研究表明，isiA 表达取决于生物体对缺铁的反应；一旦生长速率开始下降，isiA 表达就会开始。当柠檬酸铁浓度低于 0.7 微摩尔时，isiA 表达开启。开发了一种 PCR 方法，用于从多种蓝藻中特异性扩增铁调节的 isiA 基因。在我们设计了简并引物后，从藻类保藏中心获得的菌株、新分离株和富集的野外样本中扩增、克隆并测序了 15 个新的 isiA 内部片段（840 碱基对）。此外，当富集的野外样本暴露于有限的铁供应时，可通过逆转录 PCR 检测到 isiA 表达。这些结果表明，确定铁调节的 isiA 表达水平可用于指示来自野外不同来源的蓝藻样本中的缺铁情况。
