title: Amperometric detection of the bacterial metabolic regulation with a microbial array chip.
abstract: 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.
authors.affiliation: Department of Biomolecular Engineering, Graduate School of Engineering, Tohoku University, Sendai 980-8579, Japan.
authors.forename: Kuniaki
authors.initials: K
authors.lastname: Nagamine
authors.forename: Nobuto
authors.initials: N
authors.lastname: Matsui
authors.forename: Takatoshi
authors.initials: T
authors.lastname: Kaya
authors.forename: Tomoyuki
authors.initials: T
authors.lastname: Yasukawa
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Shiku
authors.forename: Toru
authors.initials: T
authors.lastname: Nakayama
authors.forename: Tokuzo
authors.initials: T
authors.lastname: Nishino
authors.forename: Tomokazu
authors.initials: T
authors.lastname: Matsue
mesh_terms: D004563:Electrochemistry; D004594:Electrophysiology; D005295:Ferrocyanides / Q000737:chemistry / Q000378:metabolism; D005947:Glucose / Q000378:metabolism / Q000502:physiology; D008839:Microelectrodes; D008854:Microscopy, Electron; D010231:Paracoccus denitrificans / Q000201:enzymology / Q000378:metabolism* / Q000502:physiology; D010427:Pentose Phosphate Pathway / Q000502:physiology
chemical_list: D005295:Ferrocyanides; C020354:hexacyanoferrate II; D005947:Glucose