Expression of ompR gene in the acid adaptation and thermal resistance of Salmonella Enteritidis SE86

Abstract

Introduction: The objective of this study was to evaluate the involvement of the ompR gene in the acid adaptation and thermal resistance of S. Enteritidis SE86, responsible agent of more than 95 % of investigated food-borne diseases, throughout the last decade in Southern Brazil. In this study, we constructed a mutant strain of S. Enteritidis SE86 (ΔompR) that was attenuated by a knockout technique. The OmpR protein expression was determined in a tagged (3XFLAG) strain of S. Enteritidis SE86. Methodology: The mutant strains were cultivated separately in nutrient broth and nutrient broth supplemented with 1% glucose (NBG) to induce acid adapted cells. The organisms were exposed to different temperature such as 37 ºC, 52 ºC, and 60ºC. The survival of the SE86 wild type (WT) and attenuated strain was determined by bacterial count, and the tagged protein (ompR::3XFLAG cat::FLAG) was detected by SDS-PAGE and immunoblotting with anti-FLAG antibodies. Results: Results showed that when exposed at 52ºC, the acid-adapted SE86 WT cells were completely inactivated after 300 minutes; however, non-adapted cells (WT and ΔompR) and acid-adapted ΔompR demonstrated higher thermal sensitivity, since they were completely inactivated in 240 minutes. At 60ºC, the acid-adapted SE86 ΔompR also demonstrated higher sensitivity that SE86 WT, being totally inactivated after 15 minutes, while the WT cells were inactivated in 20 minutes. Conclusion: The acid adapted cells showed increased expression of OmpR when exposed to 52 ºC and 60ºC, this confirmed the requirement of acid adaptation for S. Enteritidis SE86 to resist elevated temperatures.

Response to Acid Adaptation in Salmonella enterica Serovar Enteritidis

“…Supporting this, the acid tolerance genes SEN1564A and cfa were upregulated in response to acid adaptation. SEN1564A encodes an acid shock protein in S. Enteritidis that is synthesized to repair or prevent acid-induced damage allowing bacterial survival at low pH (Álvarez-Ordóñez et al, 2011;Ritter et al, 2014). Cyclopropane fatty acid synthase encoded by cfa is also essential for the induction of ATR.…”

Molecular mechanism of acid stress response ofA. acidoterrestrisDSM 3922Tunder sublethal pH environment

“…In recent years, many scholars have discovered and identified protective proteins related to pH pressure. Most of the identified acid stress proteins involved in cell regulation, energy metabolism, molecular monitoring, transcription, translation, pili synthesis, cell signaling, and virulence (Ritter et al, 2014). It is reported that bacteria may activate different acid resistant systems under different pH conditions.…”

DNA Damage Protection for Enhanced Bacterial Survival Under Simulated Low Earth Orbit Environmental Conditions in Escherichia coli

“…To further study the limitations of the studied strains, as well as other bacteria, directed evolution processes could be applied to enhance the survival of the cells to vacuum or high/low temperatures. Moreover, some genes from extremophile species have been identified and related to thermal resistance (Gonzalez-Blasco et al, 2000;Zhang and Griffiths, 2003;Ritter et al, 2014), which could be introduced to the cells and characterized. However, thermal and vacuum resistance is not only a matter of genetics, but also of cell components and protein melting and degradation.…”