SulA-independent filamentation of Escherichia coli during growth after release from high hydrostatic pressure treatment
SulA-independent filamentation of Escherichia coli during growth after release from high hydrostatic pressure treatment
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DOI：
10.1007/s00253-003-1465-6
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发表时间：
2004-04-01
影响因子：
5
通讯作者：
Yamasaki, M
中科院分区：
文献类型：
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作者：
Kawarai, T;Wachi, M;Yamasaki, M
为了提高高压灭菌的效率，需要了解对高压灭菌最敏感的细菌的生化过程。我们研究了指数生长的大肠杆菌K-12细胞从HPT释放后的生长特性。我们观察到在超过75兆帕的温度下处理(37℃，30min)后的生长迟缓。在75 Mpa处理90min后，可观察到约为正常细胞长度8倍的长丝状细胞。在随后的时期，丝状细胞分裂成正常大小的细胞。RecA和Sula突变株也形成了丝状细胞，表明丝化是不依赖Sula的。核团在丝状细胞中正常分离。在延长的细胞中，在可能的分裂部位只检测到一个FtsZ环(或没有)。Western blotting分析表明，FtsZ蛋白的量不受处理的影响。然而，依赖于GTP的FtsZ蛋白在大肠杆菌粗提物中的体外聚合或纯化的FtsZ蛋白对HPT敏感。这些事实表明，在75 MPa下，HPT变性了一小部分FtsZ分子，这些变性的分子干扰了功能性FtsZ的聚合，导致FtsZ环的数量显著减少。
To improve the efficiency of sterilization by high hydrostatic pressure treatment (HPT), it is desirable to know the biochemical process of bacteria most sensitive to the treatment. We investigated growth properties after release from HPT of exponentially growing Escherichia coli K-12 cells. We observed growth retardation after treatment (30 min at 37degreesC) above 75 MPa. Long filamentous cells of about eight times normal cell length were observed at 90 min growth after treatment at 75 MPa. In the subsequent period the filamentous cells divided into normal-sized cells. recA and sulA mutant strains also formed filamentous cells, indicating that filamentation was SulA-independent. Nucleoids segregated normally in the filamentous cells. Only one FtsZ ring (or none) was detected at possible division sites in the elongated cells. Western blotting analysis demonstrated that the amount of FtsZ protein was not affected by the treatment. GTP-dependent in vitro polymerization of either FtsZ protein in E. coli crude extract or purified FtsZ protein, however, was sensitive to HPT. These facts suggest that HPT at 75 MPa denatures a fraction of FtsZ molecules, and that these denatured molecules interfere with the polymerization of functional FtsZ, resulting in the significantly reduced number of FtsZ rings.