Unité Flore Lactique et Environnement Carné, UR309, INRA, Domaine de Vilvert, F-78350 Jouy en Josas, France.
Appl Environ Microbiol. 2010 Jan;76(2):560-5. doi: 10.1128/AEM.02205-09. Epub 2009 Nov 20.
Lactobacillus sakei is a lactic acid bacterium naturally found on meat. Although it is generally acknowledged that lactic acid bacteria are rare species in the microbial world which do not have iron requirements, the genome sequence of L. sakei 23K has revealed quite complete genetic equipment dedicated to transport and use of this metal. Here, we aimed to investigate which iron sources could be used by this species as well as their role in the bacterium's physiology. Therefore, we developed a microscopy approach based on electron energy loss spectroscopy (EELS) analysis and nano-scale secondary-ion mass spectrometry (SIMS) in order to analyze the iron content of L. sakei cells. This revealed that L. sakei can use iron sources found in its natural ecosystem, myoglobin, hemoglobin, hematin, and transferrin, to ensure long-term survival during stationary phase. This study reveals that analytical image methods (EELS and SIMS) are powerful complementary tools for investigation of metal utilization by bacteria.
清酒乳杆菌是一种天然存在于肉类中的乳酸菌。尽管人们普遍认为，乳酸菌是微生物世界中罕见的不需要铁的物种，但清酒乳杆菌 23K 的基因组序列揭示了相当完整的专门用于运输和使用这种金属的遗传设备。在这里，我们旨在研究该物种可以利用哪些铁源以及它们在细菌生理学中的作用。因此，我们开发了一种基于电子能量损失光谱 (EELS) 分析和纳米级二次离子质谱 (SIMS) 的显微镜方法，以分析清酒乳杆菌细胞中的铁含量。这表明清酒乳杆菌可以利用其天然生态系统中的铁源，如肌红蛋白、血红蛋白、血卟啉和转铁蛋白，以确保在静止期的长期生存。这项研究表明，分析图像方法 (EELS 和 SIMS) 是研究细菌利用金属的有力补充工具。
