title: Difference of EGCg adhesion on cell surface between Staphylococcus aureus and Escherichia coli visualized by electron microscopy after novel indirect staining with cerium chloride.
abstract: We developed a novel method using indirect staining with cerium chloride for visualization of the catechin derivative epigallocatechin gallate (EGCg) on the surface of particles, i.e., polystyrene beads and bacterial cells, by electron microscopy. The staining method is based on the fact that in an alkaline environment, EGCg produces hydrogen peroxide, and then hydrogen peroxide reacts with cerium, resulting in a cerium hydroperoxide precipitate. This precipitate subsequently reacts with EGCg to produce larger deposits. The amount of precipitate is proportional to the amount of EGCg. Highly EGCg-sensitive Staphylococcus aureus and EGCg-resistant Escherichia coli were treated with EGCg under various pH conditions. Transmission electron microscopy observation showed that the amount of deposits on S. aureus increased with an increase in EGCg concentration. After treating bacterial cells with 0.5mg/mL EGCg (pH 6.0), attachment of EGCg was significantly lower to E. coli than to S. aureus. This is the first report that shows differences in affinity of EGCg to the cell surfaces of Gram-positive and -negative bacteria by electron microscopy.
authors.affiliation: Kao Corporation, 2606 Akabane, Ichikai-machi, Haga-gun, Tochigi 321-3497, Japan. nakayama.motokazu@kao.co.jp
authors.forename: Motokazu
authors.initials: M
authors.lastname: Nakayama
authors.forename: Naofumi
authors.initials: N
authors.lastname: Shigemune
authors.forename: Takashi
authors.initials: T
authors.lastname: Tsugukuni
authors.forename: Hajime
authors.initials: H
authors.lastname: Tokuda
authors.forename: Takahisa
authors.initials: T
authors.lastname: Miyamoto
mesh_terms: D002392:Catechin / Q000031:analogs & derivatives* / Q000737:chemistry; D002563:Cerium / Q000737:chemistry*; D004396:Coloring Agents / Q000737:chemistry*; D004926:Escherichia coli / Q000737:chemistry* / Q000648:ultrastructure; D008854:Microscopy, Electron; D013194:Staining and Labeling / Q000295:instrumentation / Q000379:methods*; D013211:Staphylococcus aureus / Q000737:chemistry* / Q000648:ultrastructure
chemical_list: D004396:Coloring Agents; D002563:Cerium; D002392:Catechin; C045651:epigallocatechin gallate; C026690:cerous chloride