Motility, Chemotaxis, and Flagella

Excerpt

For many pathogenic bacteria, flagellum-dependent motility and chemotaxis are crucial factors in the process of colonization of the host organism and establishment of a successful infection (reviewed in references and 39). The flagella of Helicobacter pylori have been extensively studied, and convincing evidence is available demonstrating the key role of these organelles in the colonization of the human gastric mucosa by this fastidious pathogen. Experiments with gnotobiotic piglets have established a correlation between the motility state of some H. pylori isolates and their ability to colonize the gastric epithelium (11, 12). The characterization of isogenic mutants deficient in specific flagellar proteins has confirmed the importance of an intact flagellar apparatus and the resulting motility for H. pylori pathogenicity (8, 13, 17, 21, 28, 29). Structural components of the flagellum as well as secretory and regulatory proteins involved in the synthesis of the flagellar apparatus and the control of chemotaxis have been analyzed in recent years, and our knowledge regarding the mechanisms of H. pylori motility is rapidly increasing. This chapter summarizes the available experimental and genomic data on flagellar function and provides an overview of our current knowledge of this field. The emphasis will be on the regulation of flagellar gene transcription and chemotaxis, while a more detailed description of the morphology of the H. pylori flagellum will be given in chapter 7.