Cellular response of Shewanella oneidensis to strontium stress
Cellular response of Shewanella oneidensis to strontium stress
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DOI：
10.1128/aem.72.1.890-900.2006
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发表时间：
2006-01-01
影响因子：
4.4
通讯作者：
Thompson, DK
中科院分区：
文献类型：
--
作者：
Brown, SD;Martin, M;Thompson, DK
研究了金属离子还原细菌白氏杆菌MR-1菌株对非放射性锶暴露的生理学和转录组动力学。研究表明，MR-1能够在含有180 mM氯化锶的复合培养基中有氧生长，但在高于该浓度时表现出严重的生长抑制。用180 mM的氯化锶冲击有氧生长的指数期中期的MR-1细胞，并参照非应激的MR-1细胞的数据分析了mRNA丰度的显著差异。与亲本和野生型菌株相比，在铁载体生物合成和铁运输中具有注释功能的基因是对急性锶胁迫反应最高的(>；100倍[P<；0.05])开放阅读框，并且发现铁载体产生缺陷的突变(SO3032：：pKNOCK)对SrCl2暴露高度敏感。编码多种药物和重金属外排泵、渗透调节相关蛋白、硫酸盐ABC转运蛋白和硫代谢同化酶的转录本在锶暴露后也有差异表达，但水平比铁运输基因低几个数量级。在用50、100或150 mM SrCl2修饰的肉汤培养物中观察到MR-1在有氧生长过程中形成沉淀，但在SO3032：：pKNOCK突变体或非生物对照的培养物中没有观察到沉淀的形成。利用激光诱导击穿光谱和静态二次离子质谱仪对该沉淀物进行的化学分析表明，锶在细胞外以固相隔离的方式存在，至少部分重金属与碳酸盐相结合。
The physiology and transcriptome dynamics of the metal ion-reducing bacterium Shewanella oneidensis strain MR-1 in response to nonradioactive strontium (Sr) exposure were investigated. Studies indicated that MR-1 was able to grow aerobically in complex medium in the presence of 180 mM SrCl2, but showed severe growth inhibition at levels above that concentration. Temporal gene expression profiles were generated from aerobically grown, mid-exponential-phase MR-1 cells shocked with 180 mM SrCl2, and analyzed for significant differences in mRNA abundance with reference to data for nonstressed MR-1 cells. Genes with annotated functions in siderophore biosynthesis and iron transport were among the most highly induced (> 100-fold [P < 0.05]) open reading frames in response to acute Sr stress, and a mutant (SO3032::pKNOCK) defective in siderophore production was found to be hypersensitive to SrCl2 exposure, compared to parental and wild-type strains. Transcripts encoding multidrug and heavy metal efflux pumps, proteins involved in osmotic adaptation, sulfate ABC transporters, and assimilative sulfur metabolism enzymes also were differentially expressed following Sr exposure but at levels that were several orders of magnitude lower than those for iron transport genes. Precipitate formation was observed during aerobic growth of MR-1 in broth cultures amended with 50, 100, or 150 mM SrCl2, but not in cultures of the SO3032::pKNOCK mutant or in the abiotic control. Chemical analysis of this precipitate using laser-induced breakdown spectroscopy and static secondary ion mass spectrometry indicated extracellular solid-phase sequestration of Sr, with at least a portion of the heavy metal associated with carbonate phases.