INVASION BY SALMONELLA-TYPHIMURIUM IS AFFECTED BY THE DIRECTION OF FLAGELLAR ROTATION
INVASION BY SALMONELLA-TYPHIMURIUM IS AFFECTED BY THE DIRECTION OF FLAGELLAR ROTATION
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DOI：
10.1128/iai.60.6.2475-2480.1992
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发表时间：
1992-06-01
影响因子：
3.1
通讯作者：
FALKOW, S
中科院分区：
文献类型：
--
作者：
JONES, BD;LEE, CA;FALKOW, S
当需氧生长时，鼠伤寒沙门氏菌表现出低水平进入组织培养细胞。我们已经分离出一种鼠伤寒沙门氏菌Tn10突变体，当在有氧条件下生长时，它能有效地侵入HEp-2细胞。鼠伤寒沙门氏菌Tn10元件附近的DNA测序结果显示，该插入干扰了天冬氨酸受体基因tar的转录。转座子对下游基因的极性效应也消除了趋化性。等基因非趋化性（Che-），以及非运动性（Mot-）和非鞭毛性（Fla-），鼠伤寒沙门氏菌菌株入侵HEp-2细胞的能力进行了检测。“平滑”游泳Che-突变体（cheA, cheW， cheR和cheY）被发现对培养的哺乳动物细胞具有增强的侵袭性。相比之下，发现“tumbly”cheB突变体和Mot-（鞭毛）菌株具有降低的组织培养侵袭性水平。如果使用离心来促进与单层表面的接触，发现Fla-菌株具有与野生型菌株一样的侵袭性。此外，当引入mot或fla突变使该菌株瘫痪时，所观察到的平滑游泳tar::Tn10突变体的高侵袭性被抑制。用小鼠感染模型证明，在体内也观察到突变的侵袭性表型。这些数据与细菌周围鞭毛的旋转和物理方向影响沙门氏菌进入宿主细胞的能力的观点最为一致。
When grown aerobically, Salmonella typhimurium exhibits a low level of entry into tissue culture cells. We have isolated an S. typhimurium Tn10 mutant which, when grown under aerobic conditions, efficiently invades HEp-2 cells. Sequencing of S. typhimurium DNA adjacent to the site of the Tn10 element showed that the insertion disrupted transcription of the aspartate receptor gene, tar. Polar effects of the transposon on downstream genes also eliminated chemotaxis. Isogenic nonchemotactic (Che-), as well as nonmotile (Mot-) and nonflagellated (Fla-), S. typhimurium strains were examined for their ability to invade HEp-2 cells. "Smooth" swimming Che- mutants (cheA, cheW, cheR, and cheY) were found to possess increased invasiveness for cultured mammalian cells. In contrast, a "tumbly" cheB mutant and Mot- (flagellated) strain were found to have decreased levels of tissue culture invasiveness. A Fla- strain was found to be as invasive as the wild-type strain if centrifugation was used to facilitate contact with the monolayer surface. In addition, the observed hyperinvasiveness of the smooth swimming tar::Tn10 mutant was suppressed when the strain was paralyzed by the introduction of a mot or fla mutation. A murine infection model was used to demonstrate that the mutant invasive phenotypes were also observed in vivo. These data are most consistent with the idea that the rotation and physical orientation of flagella around the bacteria affect the ability of salmonellae to enter host cells.