Pseudomonas aeruginosa as a model microorganism for investigation of chemotactic behaviors in ecosystem.
Motile bacteria sense changes in the concentration of chemicals in environments and respond in a behavioral manner. This behavioral response is called chemotaxis. Bacterial chemotaxis can be viewed as an important prelude to metabolism, prey-predator relationships, symbiosis, infections, and other ecological interactions in biological communities. Genome analysis reveals that a large number of environmental motile bacteria possess a number of genes involved in chemosensing and chemotatic signal transduction. Pseudomonas aeruginosa has a very complex chemosensory system with more than 20 chemotaxis (che) genes in five distinct clusters and 26 chemoreceptor (methyl-accepting chemotaxis protein [mcp]) genes. Among the 26 MCPs of P. aeruginosa, nine have been identified as MCPs for amino acids, inorganic phosphate, oxygen, ethylene, and volatile chlorinated aliphatic hydrocarbons, whereas 3 MCPs were demonstrated to be involved in biofilm formation and biosynthesis of type IV pilus. Six che genes are essential for chemotactic responses, while genes in Pil-Chp cluster and Wsp cluster are involved in type IV pilus synthesis and twitching motility and biofilm formation, respectively. P. aeruginosa, with its complex chemotaxis system, is a better model microorganism for investigating ecological aspects of chemotaxis in environmental bacteria than Escherichia coli and Salmonella enterica serovar Typhimurium, which possess a relatively simpler chemotaxis system.
Kato
Junichi
J
Department of Molecular Biotechnology, Hiroshima University, Higashi-Hiroshima, Hiroshima 739-8530, Japan. jun@hiroshima-u.ac.jp
Kim
Hye-Eun
HE
Takiguchi
Noboru
N
Kuroda
Akio
A
Ohtake
Hisao
H
D002633:Chemotaxis / Q000502:physiology*; D017753:Ecosystem; D008962:Models, Theoretical; D011550:Pseudomonas aeruginosa / Q000502:physiology*