• 作者： Chun-Hsing Liao, Hsu-Feng Lu, Hsin-Hui Huang, Yu Chen, Li-Hua Li, Yi-Tsung Lin & Tsuey-Ching Yang
• 作者服務機構： 1.Department of Biotechnology and Laboratory Science in Medicine, National Yang Ming Chiao Tung University, Taipei, Taiwan 2.Department of Medical Laboratory Science and Biotechnology, Asia University, Taichung, Taiwan 3.Department of Medicine, National Yang Ming Chiao Tung University, Taipei, Taiwan 4.Department of Pathology and Laboratory Medicine, Taipei Veterans General Hospital, Taipei, Taiwan 5.Division of Infectious Disease, Far Eastern Memorial Hospital, New Taipei City, Taiwan 6.Division of Infectious Diseases, Department of Medicine, Taipei Veterans General Hospital, Taipei, Taiwan
• 中文摘要：
• 英文摘要：
  Background: Stenotrophomonas maltophilia, a member of γ-proteobacteria, is a ubiquitous environmental bac‑
  terium that is recognized as an opportunistic nosocomial pathogen. FecABCD system contributes to ferric citrate
  acquisition in Escherichia coli. FeoABC system, consisting of an inner membrane transporter (FeoB) and two cytoplas‑
  mic proteins (FeoA and FeoC), is a well-known ferrous iron transporter system in γ-proteobacteria. As revealed by
  the sequenced genome, S. maltophilia appears to be equipped with several iron acquisition systems; however, the
  understanding of these systems is limited. In this study, we aimed to elucidate the ferric citrate acquisition system of S.
  maltophilia.
  Methods: Candidate genes searching and function validation are the strategy for elucidating the genes involved
  in ferric citrate acquisition. The candidate genes responsible for ferric citrate acquisition were frstly selected using
  FecABCD of E. coli as a reference, and then revealed by transcriptome analysis of S. maltophilia KJ with and without
  2,2′-dipyridyl (DIP) treatment. Function validation was carried out by deletion mutant construction and ferric citrate
  utilization assay. The bacterial adenylate cyclase two-hybrid system was used to verify intra-membrane protein–pro‑
  tein interaction.
  Results: Smlt2858 and Smlt2356, the homologues of FecA and FecC/D of E. coli, were frst considered; however,
  deletion mutant construction and functional validation ruled out their involvement in ferric citrate acquisition. FciA
  (Smlt1148), revealed by its upregulation in DIP-treated KJ cells, was the outer membrane receptor for ferric citrate
  uptake. The fciA gene is a member of the fciTABC operon, in which fciT, fciA, and fciC participated in ferric citrate
  acquisition. Uniquely, the Feo system of S. maltophilia is composed of a cytoplasmic protein FeoA, an inner membrane
  transporter FeoB, and a predicted inner membrane protein FeoI. The intra-membrane protein–protein interaction
  between FeoB and FeoI may extend the substrate profle of FeoB to ferric citrate. FeoABI system functioned as an
  inner membrane transporter of ferric citrate.
• 中文關鍵字：
• 英文關鍵字： Stenotrophomonas maltophilia, Ferric citrate, Feo system, Iron homeostasis