Starved Escherichia coli preserve reducing power under nitric oxide stress
Artikel i vetenskaplig tidskrift, 2016

Nitric oxide (NO) detoxification enzymes, such as NO dioxygenase (NOD) and NO reductase (NOR), are important to the virulence of numerous bacteria. Pathogens use these defense systems to ward off immune-generated NO, and they do so in environments that contain additional stressors, such as reactive oxygen species, nutrient deprivation, and acid stress. NOD and NOR both use reducing equivalents to metabolically deactivate NO, which suggests that nutrient deprivation could negatively impact their functionality. To explore the relationship between NO detoxification and nutrient deprivation, we examined the ability of Escherichia coli to detoxify NO under different levels of carbon source availability in aerobic cultures. We observed failure of NO detoxification under both carbon source limitation and starvation, and those failures could have arisen from inabilities to synthesize Hmp (NOD of E. coli) and/or supply it with sufficient NADH (preferred electron donor). We found that when limited quantities of carbon source were provided, NO detoxification failed due to insufficient NADH, whereas starvation prevented Hmp synthesis, which enabled cells to maintain their NADH levels. This maintenance of NADH levels under starvation was confirmed to be dependent on the absence of Hmp. Intriguingly, these data show that under NO stress, carbon-starved E. con are better positioned with regard to reducing power to cope with other stresses than cells that had consumed an exhaustible amount of carbon. (C) 2016 Elsevier Inc. All rights reserved.

Nitric oxide dioxygenase

hmp

dioxygenase

flavohemoglobin

Biophysics

Flavohemoglobin

steady-state

Carbon source

Biochemistry & Molecular Biology

gene

Hmp

regulator

NADH

Författare

G. O. F. Gowers

Jonathan Robinson

Chalmers, Biologi och bioteknik, Systembiologi

M. P. Brynildsen

Biochemical and Biophysical Research Communications

0006-291X (ISSN) 1090-2104 (eISSN)

Vol. 476 1 29-34

Ämneskategorier

Mikrobiologi

DOI

10.1016/j.bbrc.2016.05.082

PubMed

27207837