Protein-L-Isoaspartyl Methyltransferase (PIMT) Is Required for Survival of Salmonella Typhimurium at 42°C and Contributes to the Virulence in Poultry.

Pavan K Pesingi,Tapas K Goswami,Manoj Kumawat,Pranatee Behera,Manish Mahawar,Rajesh K Agarwal,Sunil K Dixit

doi:10.3389/fmicb.2017.00361

Pavan K Pesingi, Tapas K Goswami + Show 5 more

Open Access

https://doi.org/10.3389/fmicb.2017.00361

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Abstract

Poultry birds are asymptomatic reservoir of Salmonella Typhimurium (S. Typhimurium) but act as source of human infection for this bacterium. Inside the poultry, S. Typhimurium experiences several stresses, 42°C body temperature of birds is one of them. Proteins are highly susceptible to temperature mediated damage. Conversion of protein bound aspartate (Asp) residues to iso-aspartate (iso-Asp) is one of such modifications that occur at elevated temperature. Iso-Asp formation has been linked to protein inactivation and compromised cellular survival. Protein-L-isoaspartyl methyltransferase (PIMT) can repair iso-Asp back to Asp, thus enhances the cellular survival at elevated temperature. Here, we show that the pimt gene deletion strain of S. Typhimurium (Δpimt mutant strain) is hypersensitive to 42°C in vitro. The hypersusceptibility of Δpimt strain is partially reversed by plasmid based complementation (trans-complementation) of Δpimt strain. Following oral inoculation, Δpimt strain showed defective colonization in poultry caecum, and compromised dissemination to spleen and liver. Interestingly, we have observed three and half folds induction of the PIMT protein following exposure of S. Typhimurium to 42°C. Our data suggest a novel role of pimt gene in the survival of S. Typhimurium at elevated temperature and virulence.

Highlights

polymerase chain reaction (PCR) based analysis confirmed the deletion of pimt gene (Figure 1B)
Western blot analysis confirmed the presence of Protein-Lisoaspartyl methyltransferase (PIMT) in wild type and complemented strains S
We have evaluated the role of pimt gene in the survival of S

Summary

Introduction

Typhimurium) has worldwide prevalence and is a leading cause of food borne gastroenteritis (Yeung et al, 2014; Khoo et al, 2015). There are two types of Salmonella infections, including typhoidal and non-typhoidal (Darwin and Miller, 1999; Gal-Mor et al, 2014). Non-typhoidal Salmonella organisms are most common foodborne pathogens. The manifestations of non-typhoidal salmonellosis include mild to moderate gastroenteritis consisting of diarrhea, abdominal cramps, vomiting, and fever (Griffin and McSorley, 2011). The invasive infections can lead to septicaemia (Cohen et al, 1987). Non-typhoidal salmonellosis accounts for about 93.8 million cases with 155,000 deaths annually around the globe (Majowicz et al, 2010)

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