Schwan William R, Flohr Nicole L, Multerer Abigail R, Starkey Jordan C
Department of Microbiology University of Wisconsin-La Crosse, La Crosse, WI.
World J Clin Infect Dis. 2020 May 15;10(1):14-23. doi: 10.5495/wjcid.v10.i1.14.
() express flagella to ascend human urinary tracts. To survive in the acidic pH of human urine, uses the glutamate decarboxylase acid response system, which is regulated by the GadE protein.
To determine if growth in an acidic pH environment affected transcription and whether GadE regulated that transcription.
A reporter fusion was created on a single copy number plasmid to assess the effects of acidic pH on transcription. Further, a Δ mutant strain of a uropathogenic was created and tested for motility compared to the wild-type strain.
cells carrying the fusion displayed significantly less transcription when grown in an acidic pH medium compared to when grown in a neutral pH medium. Transcription of fell further when the was grown in an acidic pH/high osmolarity environment. Since GadE is a critical regulator of one acid response system, transcription was tested in a mutant strain grown under acidic conditions. Expression of was derepressed in the mutant strain grown under acidic conditions compared to that in wild-type bacteria under the same conditions. Furthermore, a mutation in a uropathogenic background exhibited significantly greater motility than the wild-type strain following growth in an acidic medium.
Together, our results suggest that GadE may down-regulate transcription and motility in grown under acidic conditions.
（某细菌）表达鞭毛以上行至人类泌尿道。为在人类尿液的酸性pH环境中存活，（该细菌）利用由GadE蛋白调控的谷氨酸脱羧酶酸反应系统。
确定在酸性pH环境中的生长是否影响（该细菌的）转录以及GadE是否调控该转录。
在单拷贝数质粒上构建一个（某基因）报告融合体，以评估酸性pH对（该细菌）转录的影响。此外，构建了一株尿路致病性（该细菌）的Δ突变株，并与野生型菌株比较其运动性。
携带（该基因）融合体的（该细菌）细胞在酸性pH培养基中生长时，与在中性pH培养基中生长相比，显示出显著更少的（该基因）转录。当（该细菌）在酸性pH/高渗透压环境中生长时，（该基因）的转录进一步下降。由于GadE是一种酸反应系统的关键调节因子，在酸性条件下生长的（该细菌）突变株中测试了（该基因）转录。与相同条件下的野生型细菌相比，在酸性条件下生长的（该细菌）突变株中（该基因）的表达被去抑制。此外，尿路致病性（该细菌）背景中的（某）突变在酸性培养基中生长后表现出比野生型菌株显著更大的运动性。
总之，我们的结果表明，GadE可能在酸性条件下生长的（该细菌）中下调（该基因）转录和运动性。
