Nagamine Kuniaki, Matsui Nobuto, Kaya Takatoshi, Yasukawa Tomoyuki, Shiku Hitoshi, Nakayama Toru, Nishino Tokuzo, Matsue Tomokazu
Department of Biomolecular Engineering, Graduate School of Engineering, Tohoku University, Sendai 980-8579, Japan.
Biosens Bioelectron. 2005 Jul 15;21(1):145-51. doi: 10.1016/j.bios.2004.08.039.
A microbial array chip with collagen gel spots entrapping living bacterial cells has been applied to investigate the metabolic regulation in Paracoccus denitrificans. Scanning electrochemical microscopy (SECM) was used to monitor the ferrocyanide production that reflects the electron flow in the respiratory chain located within the internal membrane of P. denitrificans. The ferrocyanide production from P. denitrificans largely depends on the types of the carbon source (glucose or lactate), suggesting that the electron flow rate in the respiratory chain depends on the activity of the metabolic pathway located up-stream of the respiratory chain. More importantly, it was found that the enzymes affecting glucose catabolic reactions were significantly up-regulated in cultures with a nutrient agar medium containing D-(+)-glucose as a sole carbon source. Enzyme assays using crude extracts of P. denitrificans were carried out to identify the enzymes expressed at a higher level in cultures supplemented with D-(+)-glucose. It was confirmed that the pyruvate kinase and enzymes of the overall Entner-Doudoroff pathway were highly induced in cultures containing D-(+)-glucose.
一种带有包裹活细菌细胞的胶原凝胶斑点的微生物阵列芯片已被用于研究反硝化副球菌中的代谢调控。扫描电化学显微镜（SECM）用于监测亚铁氰化物的产生，该产生反映了位于反硝化副球菌内膜内的呼吸链中的电子流。反硝化副球菌产生的亚铁氰化物很大程度上取决于碳源的类型（葡萄糖或乳酸盐），这表明呼吸链中的电子流速率取决于位于呼吸链上游的代谢途径的活性。更重要的是，发现在以D-(+)-葡萄糖作为唯一碳源的营养琼脂培养基培养物中，影响葡萄糖分解代谢反应的酶显著上调。使用反硝化副球菌的粗提物进行酶分析，以鉴定在补充有D-(+)-葡萄糖的培养物中表达水平较高的酶。证实丙酮酸激酶和整个Entner-Doudoroff途径的酶在含有D-(+)-葡萄糖的培养物中被高度诱导。
