The population surface migration and quroum-sensing system in Serratia marcescens

• Main Authors: SOO, PO-CHI, 蘇伯琦
• Other Authors: HO SHEN-WU
• Format: Others
• Language: zh-TW
• Published: 1998
• Online Access: http://ndltd.ncl.edu.tw/handle/59572985550931178565

碩士 === 國立臺灣大學 === 醫事技術學系研究所 === 86 === Abstract Serratia marcescens shows cell differentiation phenomena and population surface migration (swarming) on LB swarming agar plates. The underlying mechanisms why such phenomena occur are not clear and it is postulated that solid surface contact is an essential factor for the initiation of cell differentiation. The acyl homoserine lactone (AHL) signals are reported to be involved in the regulation of initiation of swarming in Serratia liquefaciens. A series of similar AHL signals are also observed to have significant effects on the swarming behaviour of S. marcescens. As RspA is reported to inhibit the amount of a Vibrio fischeri quorum-sensing AHL signal(OHHL) after it is synthesized in Escherichia coli, I hypothesized that RspA can affect the swarming behaviour of S. marcescens through regulation of the amount of AHL signals. A rspA gene was cloned from S. marcescens by using polymerase chain reaction (PCR). Results showed that while S. marcescens swarming is inhibited in-trans by multi-copy rspASm, the amount of AHL signal synthesized is not affected. A possible explanation for this observation is discussed. Many groups of bacteria exhibit cooperative behavioral patterns such as bioluminescence emission, antibiotic production, virulence factor expression and the population surface migration (swarming). I show here that in S. marcescens diffusible signal molecules are involved in the initiation of swarming. Synthesis of the signals is dependent on a functional smaI gene, the predicted translation product of which exhibits substantial homology to the luxI family of putative homoserine lactone synthase. These results add swarming motility to the rapidly expanding list of phenotypes known to be controlled by quorum-sensing signal molecules. My data showed that the initiation of swarming was controlled through quorum sensing system and smaI was important for the process of swarming but not for the initiation of cell differentiation. 褲年度：86 學期：2 校院：國立台灣大學 系所：醫事技術學系研究所 論文名稱(中)：以微衛星標記分析台灣地區膀胱癌患者 ! 論文名稱(英)：MIcrosatellite Analysis of Bladder Cancer in Taiwan 學位類別：碩士 語文別：chi ! 學號：R85424015 提要開放使用：是 頁數：2 研究生(中)姓：鄭 研究生(中)名：靜芸 研究生(英)姓：Cheng 研究生(英)名：Ching-Yurn Mcrosatellite (short tandem repeat) are repeatitive saquence of mostly 2 to 4 nucleotides with a widespread occurence particularly in multicellular organ isms. In the process of tumor formation, the cell might have LOH (loss of hete rozygosity) or genomic instability. Repeat saquence such as microsatellite sl ip easily during DNA replication and induce microsatellite expansion or deleti on. IF the vriable region is in the proximity of proto-oncogenes or tumor sup pressor genes,function of these genes may be altered and induce cancer. Theref ore, microsatellite has been used as a tool to detect human cancers, includin g lung, bladder, liver and breast cancers. 27 patietnes with TCC (transitional cell carcinoma) of bladder cancer were screened with eleven microsatellite markers that were widely used in detection of LOH a nd genomic instability of bladder cancer.Our results that 17 out of 27 patient s (63%) have LOH and genomic instability and the frequence of mutation is high er on chromosome 9.