The Regulatory Roles of ncRNA Rli60 in Adaptability of Listeria monocytogenes to Environmental Stress and Biofilm Formation

Abstract

Listeria monocytogenes is a facultative anaerobic Gram-positive bacterium. It is well adapted to external environments and able to infect both humans and animals. To understand the impacts of ncRNA Rli60 on the adaptability of L. monocytogenes to environmental stresses and biofilm formation, a rli60 deletion strain of L. monocytogenes (LM-Δrli60) was constructed using splicing by overlap extension PCR (SOE-PCR) and homologous recombination and then compared it with wild-type strain L. monocytogenes EGD-e in the aspects of adaptability to environmental stresses by measuring their growth under stresses of different temperatures, and acidic, alkaline, hypertonic and alcoholic conditions, and capability of biofilm formation by using crystal violet staining, as well as the transcriptional levels of genes (gltB and gltC) related to the biofilm formation by real-time quantitative PCR (qRT-PCR). The results showed that (1) the growth of LM-Δrli60 strain was significantly slower under environmental stresses of low temperature (30 °C), high temperature (42 °C), as well as alkaline and alcoholic conditions, (2) the amount of biofilm formed by LM-Δrli60 was attenuated, and (3) the transcriptional levels of gltB and gltC genes at 24 h and 48 h in LM-Δrli60 revealed a significant reduction. Overall, the results confirmed that ncRNA Rli60 plays important roles in regulating the adaptability of L. monocytogenes to environmental stresses and biofilm formation possibly through impacting the expression of gltB and gltC genes.

Transcriptomic Analysis of the Adaptation of Listeria monocytogenes to Lagoon and Soil Matrices Associated with a Piggery Environment: Comparison of Expression Profiles

“…Like in other bacterial models, ncRNAs play a central role in the adaptation of L. monocytogenes to its environment. So far, a role for the non-coding part of the genome has been reported in the regulation of virulence (Mandin et al, 2007 ; Loh et al, 2009 ; Toledo-Arana et al, 2009 ; Mraheil et al, 2011 ; Nielsen et al, 2011 ; Mellin and Cossart, 2012 ), in the transport and metabolism of sugars (Mandin et al, 2007 ; Nielsen et al, 2011 ), in the transport of metal ions (Wurtzel et al, 2012 ), in the synthesis of vitamins (Mellin and Cossart, 2012 ), in the formation of biofilm (Peng et al, 2016 ) and in the regulation of motility (Mellin and Cossart, 2012 ). In our study, we found that Rli28, Rli31, Rli38, Rli49, and Rli50, which are involved in invasion of the host's blood system, in the regulation of virulence factors (Toledo-Arana et al, 2009 ), in intracellular multiplication in mouse macrophage P338D1 and complete virulence in Galleria mellonella models (Mraheil et al, 2011 ), had lower transcript levels after incubation in the lagoon environment.…”

“…Conversely, Rli60 was found in the set of ncRNAs with higher transcript levels. This ncRNA has recently been reported to play a role in the response (growth and biofilm formation) of L. monocytogenes EGD-e to environmental stresses (temperature, pH, osmotic pressure, alcohol; Peng et al, 2016 ).…”

Stress survival islet 1 contributes to serotype-specific differences in biofilm formation in Listeria monocytogenes

“…The ability of L. monocytogenes to adapt and survive under stresses such as extreme temperatures, alkaline pH and the presence of ethanol, has been associated with the ability to form biofilms (Peng et al . ). While SSI‐1 demonstrably plays a clear role in survival within stressful environments typically encountered in the food processing environment, its role in enabling adherence and subsequent biofilm formation in environmental isolates of L. monocytogenes remains unknown.…”

Listeria monocytogenes’in RNase III rncS Geninin Silinmesinin Stres Tepkisi, Biyofilm Oluşumu ve Virülansı Üzerine Etkileri

“…Briefly, 200 μL of LM EGD-e and LM-ΔrncS bacterial culture were added to a 96-well microplate, and the biofilm was prepared using the method of crystal violet staining as described by Peng [13] . Each sample was divided into 3 groups, with 8 replicates in each group, and the OD 570 nm value was determined by enzyme-linked detector (BIOTEK, USA).…”