The influence of ribosome modulation factor on the survival of stationary-phase Escherichia coli during acid stress

Abstract

Ribosome modulation factor (RMF) was shown to have an influence on the survival of Escherichia coli under acid stress during stationary phase, since the viability of cultures of a mutant strain lacking functional RMF decreased more rapidly than that of the parent strain at pH 3. Loss of ribosomes was observed in both strains when exposed to low pH, although this occurred at a higher rate in the RMF-deficient mutant strain, which also suffered from higher levels of rRNA degradation. It was concluded that the action of RMF in limiting the damage to rRNA contributed to the protection of E. coli under acid stress. Expression of the rmf gene was lower during stationary phase after growth in acidified media compared to media containing no added acid, and the increased rmf expression associated with transition from exponential phase to stationary phase was much reduced in acidified media. It was demonstrated that RMF was not involved in the stationary-phase acid-tolerance response in E. coli by which growth under acidic conditions confers protection against subsequent acid shock. This response was sufficient to overcome the increased vulnerability of the RMF-deficient mutant strain to acid stress at pH values between 6.5 and 5.5.

Resuscitation of Pseudomonas aeruginosa from dormancy requires hibernation promoting factor (PA4463) for ribosome preservation

“…1A). In addition, and in contrast to published results for RMF in E. coli (24)(25)(26)(27), the P. aeruginosa Δrmf mutant did not show an observable survival phenotype compared with the wild-type strain when exposed to osmotic shock, heat shock, acid stress, or sensitivity to gentamicin. In contrast, a deletion of PA4463 (Δhpf) resulted in a decrease in cell recovery following starvation (P < 0.0001).…”

RNA sequencing provides evidence for functional variability between naturally co-existing Alteromonas macleodii lineages

“…Other highly expressed genes encoded two ribosome-associated proteins, ribosome modulation factor (RMF) and ribosome release factor (RRF). In Escherichia coli RMF was shown to have an influence on the protection against acid stress during stationary phase [26] and heat stress [27] acting as a protective factor of ribosomes during times of slow growth. Moreover, RRF is involved in the dissociation of ribosomes from mRNA and is essential for bacterial growth [28].…”

Identification of Campylobacter jejuni Genes Contributing to Acid Adaptation by Transcriptional Profiling and Genome-Wide Mutagenesis

“…One possible explanation for the failure of growth at pH 5.5 to cause the repression of genes encoding ribosomal proteins is that growth at this lower pH is damaging to ribosomes, and survival and/or adaptation relies on the continued synthesis of ribosomal proteins. In fact, the loss of ribosomes has been reported for E. coli exposed to medium at pH 3 (25).…”