Role of flhDC in the expression of the nuclease gene nucA, cell division and flagellar synthesis in Serratia marcescens.
Role of flhDC in the expression of the nuclease gene nucA, cell division and flagellar synthesis in Serratia marcescens.
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DOI：
10.1007/bf02253363
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发表时间：
2000-11
影响因子：
11
通讯作者：
Jia-Hurng Liu;Meng-Jiun Lai;S. Ang;J. Shu;P. Soo;Y. Horng;Wen-Ching Yi;Hsin-Chih Lai;
中科院分区：
文献类型：
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作者：
Jia-Hurng Liu;Meng-Jiun Lai;S. Ang;J. Shu;P. Soo;Y. Horng;Wen-Ching Yi;Hsin-Chih Lai;
我们在粘质沙雷氏菌中研究了flhDC操纵子的功能，该操纵子控制肠道细菌的运动和细胞分裂。我们的评价包括细胞分裂，鞭毛合成和核酸酶（由thenucASm基因编码，毒力因子之一）表达的调控的研究。粘质沙雷氏菌CH-1的染色体flhDCoperon的中断导致细胞分裂异常和核酸酶和鞭毛的丢失。通过在多拷贝质粒中诱导lhDC的过表达，在flhDC突变体中恢复了nucA和其他突变表型的表达。多片flhDC也诱导形成分化的细胞（多倍体无隔细胞与周毛鞭毛的过度合成）在肉汤培养使用最低限度的生长培养基。theflhDCoperon的表达显示出正性的自身调节，并且是生长期依赖性的（在对数生长期早期上调）。此外，当温度从30 ° C增加到37°C时，以及当渗透压增加时，flhDC表达受到抑制，但不受葡萄糖分解代谢物抑制的影响。这些结果表明，FlhD/FlhC是一个多功能的转录激活因子，参与细胞分化，群集和毒力因子的表达过程。
We investigated inSerratia marcescensthe functions of theflhDCoperon, which controls motility and cell division in enteric bacteria. Included in our evaluations were investigation of cell division, flagellar synthesis and regulation of the expression of nuclease (encoded by thenucASmgene, one of the virulence factors). Interruption of the chromosomalflhDCoperon inS. marcescensCH-1 resulted in aberrant cell division and loss of nuclease and flagella. Expression ofnucASmand other mutated phenotypes was restored in theflhDCmutant by the induction of overexpression offlhDCin a multicopy plasmid. MulticopiedflhDCalso induced the formation of differentiated cells (polyploid aseptate cells with oversynthesis of peritrichous flagella) in broth culture using minimal growth medium. Expression of theflhDCoperon showed positive autoregulation, and was growth phase dependent (upregulated in early log phase). In addition,flhDCexpression was inhibited when the temperature increased from 30 to 37°C, and when osmolarity was increased, but was not influenced by glucose catabolite repression. These results show that FlhD/FlhC is a multifunctional transcriptional activator involved in the process of cell differentiation, swarming and virulence factor expression.