The physiological role of pcm-tolCsm operon in Stenotrophomonas maltophilia
| Autor: | Yun-Chen Chung, 鍾昀辰 |
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| Rok vydání: | 2015 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 103 TolC of Enterobacteriaceae is known as a promiscuous outer membtrane protein equipped with several tripartite efflux pumps which involve in the extrusion of noxious compounds. In addition, TolC in physiology of Enterobacteriaceae is very broad and affects cell adaption to adverse environments. Distinct from that of Enterobacteriaceae, the tolCsm of Stenotrophomonas maltophilia and its upstream protein-L-isoaspartate O-methyltransferase (pcm) gene form a two-member operon, and tolCsm deletion increases the susceptibility of S. maltophilia to several antimicrobial agents and chemical compounds. This study aims to further characterize the physiological roles of pcm-tolCsm operon in S. maltophilia. The physiological functions among wild-type, and its derived pcm, tolCsm, and pcm-tolCsm mutants were comparatively assessed, including (i) temperature and osmolarity adaptation, (ii) single colony size and bacteria morphology, (iii) envelope and oxidative stress tolerances, as well as (iv) secreted protease activity and swimming motility. The results demonstrated that (i) Inactivation of pcm or pcm-tolCsm resulted in the stationary-phase cells aggregation irrespective of the culture temperature or the osmolarity of culture medium. (ii) Compared with wild-type, pcm mutant displayed a morphology of small and short and its grown colony is relatively smaller. (iii) The pcm-tolCsm operon was less related to envelope stress tolerance. (iv) Deletion of pcm or pcm-tolCsm decreased the oxidative stress tolerance and upregulated the expression of katE. Furthermore, deletion of tolCsm or pcm-tolCsm upregulated the expression of sodA2. (v) Inactivation of tolCsm or pcm-tolCsm compromised the secreted protease activity. (vi) Inactivation of pcm or pcm-tolCsm enhanced the swimming motility. These findings support that pcm-tolCsm operon makes a significant contribution to the physiological functions of S. maltophilia. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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