Silva-Valenzuela Cecilia A, Velásquez Felipe, Peñailillo Johany, Garcias-Papayani Héctor, Fernández Paulina, Tobar Pía, Contreras Inés, Santiviago Carlos A, Álvarez Sergio A
Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias Químicas y Farmacéuticas, Universidad de Chile, Santiago, Chile; Department of Molecular Biology and Microbiology, Tufts University, Boston, MA, USA.
Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias Químicas y Farmacéuticas, Universidad de Chile, Santiago, Chile.
Biochem Biophys Res Commun. 2016 Sep 2;477(4):563-567. doi: 10.1016/j.bbrc.2016.06.074. Epub 2016 Jun 23.
Lipopolysaccharide (LPS) consists of three covalently linked domains: the lipid A, the core region and the O antigen (OAg), consisting of repeats of an oligosaccharide. Salmonella enterica serovar Enteritidis (S. Enteritidis) produces a LPS with two OAg preferred chain lengths: a long (L)-OAg controlled by WzzSE and a very long (VL)-OAg controlled by WzzfepE. In this work, we show that OAg produced by S. Enteritidis grown in E minimal medium also presented two preferred chain-lengths. However, a simultaneous and opposing change in the production of L-OAg and VL-OAg was observed in response to oxygen availability. Biochemical and genetics analyses indicate that this process is regulated by transcriptional factors Fnr and ArcA by means of controlling the transcription of genes encoding WzzSE and WzzfepE in response to oxygen availability. Thus, our results revealed a sophisticated regulatory mechanism involved in the adaptation of S. Enteritidis to one of the main environmental cues faced by this pathogen during infection.
脂多糖（LPS）由三个共价连接的结构域组成：脂质A、核心区域和O抗原（OAg），O抗原由寡糖重复序列组成。肠炎沙门氏菌肠炎血清型（肠炎沙门氏菌）产生的LPS具有两种OAg优先链长：由WzzSE控制的长（L）-OAg和由WzzfepE控制的非常长（VL）-OAg。在这项工作中，我们表明，在E基本培养基中生长的肠炎沙门氏菌产生的OAg也呈现出两种优先链长。然而，响应于氧气可用性，观察到L-OAg和VL-OAg的产生同时发生相反的变化。生化和遗传学分析表明，该过程受转录因子Fnr和ArcA调控，通过响应氧气可用性控制编码WzzSE和WzzfepE的基因的转录。因此，我们的结果揭示了一种复杂的调控机制，该机制参与肠炎沙门氏菌适应该病原体在感染过程中面临的主要环境线索之一。
