2004 Fiscal Year Final Research Report Summary
Tactics of Legionella to survive in the environment and in host cells, and its variety
| Project/Area Number |
14370094
|
|---|
| Research Category |
Grant-in-Aid for Scientific Research (B)
|
| Allocation Type | Single-year Grants |
|---|
| Section | 一般 |
|---|
| Research Field |
Bacteriology (including Mycology)
|
|---|
| Research Institution | KYUSHU UNIVERSITY |
|---|
Principal Investigator |
YOSHIDA Shin-ichi Kyushu University, Department of Bacteriology, Faculty of Medical Sciences, Professor, 医学研究院, 教授 (60128113)
|
|---|
| Project Period (FY) |
2002 – 2004
|
| Keywords | Legionella / biofilm / amoeba / macrophage / intracellular parasite |
|---|
| Research Abstract |
1.Biofilm formation by Legionella spp.
Among the species of Legionella, only L.pneumophila formed biofilm when it was cultured in BCYE medium at static condition. Biofilm was formed on the surface of media and on the glass near the medium surface. When the bacteria were cultured at 37C and 42C, they grew in filamentous form, but they grew in short rod form at 25C.
2.Dynamics of Legionella genes when the bacteria grow in vitro and in cells
Unstable GFP was introduced to L.pneumophila and they were used to analyze the dynamics of gene expression during growth in vitro and in macrophage cell line. The icmS, icmT and icmQ genes were expressed during the late log phase of in vitro culture.The expression was prominent 20 h after in vitro phagocytosis.
3.Entry and intracellular growth mechanism of L.dumoffii
Transposon (Tn) mutagenesis was introduced in L.dumoffii TEX-KL strain. From 700 strains harboring the Tn, two mutants showed defective intracellular growth and invasion into epithelial cells. These strains were named HOLD254 and KL15, respectively.
1)HOLD254 harbored Tn in DjlA gene, a member of heat shock protein. This is the first report which showed that a shaperon is necessary in intracellular growth.
2)KL15 strain harbored Tn in TraC gene.
4.Effect of 2-deoxy-D-glucose (2dG) on macrophages analyzed by DNA array of murine genes
2dG inhibits intracellular growth of L.pneumophila in macrophages when it was added in the culture. The effect was analyzed by the DNA array. 2dG alone suppressed some G proteins of macrophages. Infected macrophage augmented the expression of Toll-like receptor 2(TLR2) and TNF alpha genes. When 2dG was added in the infected macrophages, the expression of the two genes was suppressed.
|
