Adenosine deamination increases the survival under acidic conditions in Escherichia coli

Abstract

Aims: Resistance to acidic stress contributes to bacterial persistence in the host and is thought to promote their passage through the human gastric barrier. The aim of this study was to examine whether nucleosides have a role in the survival under acidic conditions in Escherichia coli. Methods and Results: We found that adenosine has a function to survive against extremely acidic stress. The deletion of add encoding adenosine deaminase that converts adenosine into inosine and NH3 attenuated the survival in the presence of adenosine. The addition of adenosine increased intracellular pH of E. coli cells in pH 2·5 medium. Addition of inosine or adenine did not increase the resistance to acidic conditions. Conclusions: Our present results imply that adenosine was used to survive under extremely acidic conditions via the production of NH3. Significance and Impact of the Study: It has been proposed that amino acid decarboxylation is the major system for the resistance of E. coli to acidic stress. In this study, the adenosine deamination was shown to induce the survival under acidic conditions, demonstrating that bacteria have alternative strategies to survive under acidic conditions besides amino acid decarboxylation.

Respiration and the F1Fo-ATPase Enhance Survival under Acidic Conditions in Escherichia coli

“…Our group reported that adenosine deamination increased survival under extremely acidic conditions, in addition to amino acid decarboxylation [10]. Furthermore, our group implied that ATP is required for survival under acidic conditions and that one of the ATP-dependent systems is a DNA repair system in E. coli [11].…”

“…The other two systems are arginine-dependent (AR3) [5], [6] and lysine-dependent (AR4) [7]–[9] systems. Recently an adenosine-dependent AR system was reported in E. coli , and this system was less active than AR2 but more potent than AR4 [10]. These systems were proposed to regulate the intracellular pH (pHi) at a higher level than the pH of the surroundings [1], [10].…”

Overproduction of α-Lipoic Acid by Gene Manipulated Escherichia coli

“…Trace metal mixture (1000×) contained 50 mM FeCl 3 , 20 mM CaCl 2 , 10 mM MnCl 2 and ZnSO 4 , and 2 mM CoCl 2 , CuCl 2 , NiCl 2 , Na 2 MoO 4 , Na 2 SeO 3 , and H 3 BO 3 [31]. Mutants were grown at 37°C in EG medium, which is minimal E medium containing 0.4% glucose [32, 33]. …”

Cancer Chemotherapy Specific to Acidic Nests

“…When a metabolic pathway declines at acidic pH, it would be beneficial for an alternative pathway to work to compensate the decline. It is well known that bacteria have metabolic pathways that function under acidic conditions [7]. These previous insights led us to consider that mammals also have alternative systems working in acidic diseased areas, such as cancer nests, inflammation loci, and areas of infarction.…”