Ai-Yun Lee1, Cheng-Yen Kao2, Yao-Kuan Wang3, Ssu-Yuan Lin3, Tze-Ying Lai3, Bor-Shyang Sheu4,5, Chien-Jung Lo3, Jiunn-Jong Wu2. 1. Institute of Molecular Medicine, College of Medicine, National Cheng Kung University, Tainan, Taiwan. 2. Department of Biotechnology and Laboratory Science in Medicine, School of Biomedical Science and Engineering, National Yang Ming University, Taipei, Taiwan. 3. Department of Physics and Graduate Institute of Biophysics, National Central University, Jhongli, Taiwan. 4. Department of Internal Medicine, College of Medicine, National Cheng Kung University, Tainan, Taiwan. 5. Department of Internal Medicine, Tainan Hospital, Ministry of Health & Welfare, Taiwan.
Abstract
BACKGROUND: Flagellar motility of Helicobacter pylori has been shown to be important for the bacteria to establish initial colonization. The ferric uptake regulator (Fur) is a global regulator that has been identified in H. pylori which is involved in the processes of iron uptake and establishing colonization. However, the role of Fur in H. pylori motility is still unclear. MATERIALS AND METHODS: Motility of the wild-type, fur mutant, and fur revertant J99 were determined by a soft-agar motility assay and direct video observation. The bacterial shape and flagellar structure were evaluated by transmission electron microscopy. Single bacterial motility and flagellar switching were observed by phase-contrast microscopy. Autoinducer-2 (AI-2) production in bacterial culture supernatant was analyzed by a bioluminescence assay. RESULTS: The fur mutant showed impaired motility in the soft-agar assay compared with the wild-type J99 and fur revertant. The numbers and lengths of flagellar filaments on the fur mutant cells were similar to those of the wild-type and revertant cells. Phenotypic characterization showed similar swimming speed but reduction in switching rate in the fur mutant. The AI-2 production of the fur mutant was dramatically reduced compared with wild-type J99 in log-phase culture medium. CONCLUSIONS: These results indicate that Fur positively modulates H. pylori J99 motility through interfering with bacterial flagellar switching.
BACKGROUND: Flagellar motility of Helicobacter pylori has been shown to be important for the bacteria to establish initial colonization. The ferric uptake regulator (Fur) is a global regulator that has been identified in H. pylori which is involved in the processes of iron uptake and establishing colonization. However, the role of Fur in H. pylori motility is still unclear. MATERIALS AND METHODS: Motility of the wild-type, fur mutant, and fur revertant J99 were determined by a soft-agar motility assay and direct video observation. The bacterial shape and flagellar structure were evaluated by transmission electron microscopy. Single bacterial motility and flagellar switching were observed by phase-contrast microscopy. Autoinducer-2 (AI-2) production in bacterial culture supernatant was analyzed by a bioluminescence assay. RESULTS: The fur mutant showed impaired motility in the soft-agar assay compared with the wild-type J99 and fur revertant. The numbers and lengths of flagellar filaments on the fur mutant cells were similar to those of the wild-type and revertant cells. Phenotypic characterization showed similar swimming speed but reduction in switching rate in the fur mutant. The AI-2 production of the fur mutant was dramatically reduced compared with wild-type J99 in log-phase culture medium. CONCLUSIONS: These results indicate that Fur positively modulates H. pylori J99 motility through interfering with bacterial flagellar switching.
Authors: Renato Elias Rodrigues de Souza Santos; Bianca Bontempi Batista; José Freire da Silva Neto Journal: Appl Environ Microbiol Date: 2020-10-15 Impact factor: 4.792