Strategies of Pathogens to Escape from NO-Based Host Defense

Abstract

Nitric oxide (NO) is an essential signaling molecule present in most living organisms including bacteria, fungi, plants, and animals. NO participates in a wide range of biological processes including vasomotor tone, neurotransmission, and immune response. However, NO is highly reactive and can give rise to reactive nitrogen and oxygen species that, in turn, can modify a broad range of biomolecules. Much evidence supports the critical role of NO in the virulence and replication of viruses, bacteria, protozoan, metazoan, and fungi, thus representing a general mechanism of host defense. However, pathogens have developed different mechanisms to elude the host NO and to protect themselves against oxidative and nitrosative stress. Here, the strategies evolved by viruses, bacteria, protozoan, metazoan, and fungi to escape from the NO-based host defense are overviewed.

Recurring food source‐based Listeria outbreaks in the United States: An unsolved puzzle of concern?

“…Listeria diagnosis is carried out through basic laboratory techniques, although it is complex and often lacks brevity 21 . The motility, stress tolerance and adaptability of L. monocytogenes determine its virulence and aggressive invasion into the intestinal epithelial cells (that causes intestinal infection) and various other cell types 22–24 . Hypervirulent L. monocytogenes strains with an ability to infect respiratory system (the lungs) was reported recently in a coronavirus disease‐19 (COVID‐19) pandemic patient 25 .…”

Mechanism of Peroxynitrite Interaction with Ferric M. tuberculosis Nitrobindin: A Computational Study

“…•− can also result in nitrite (NO 2 − ) and dioxygen (O 2 ). 1,3,9,10 Besides the intrinsic degradation, ONOO − also reacts with carbon dioxide (CO 2 ), leading to 1-carboxylato-2-nitrosodioxidane (ONOOC[O]O − ). In turn, ONOOC[O]O − decays through homolysis of the O−O bond, resulting in the generation of the reactive species nitrogen dioxide and trioxocarbonate radicals ( • NO 2 and CO 3…”

“…Moreover, this difference may reflect the presence or absence of cavity/tunnel systems either at the distal or proximal side of the heme pocket. 21 For example, Nbs display a heme distal side (volume ∼ 600 Å 3 ) that is directly accessible to the heme ligand from the external space. In contrast, the myoglobin distal side is not directly accessible to an external ligand, as the His64 side chain acts as a gate, modulating heme accessibility to the ligand.…”

“…Peroxynitrite (ONOO – ) is one of the most powerful biological nitrosative agents produced when nitric oxide ( • NO) and superoxide (O 2 •– ) combine at extremely rapid rates. − The reaction between • NO and O 2 •– is diffusion-controlled . The rate constant of this process (5.0 × 10 9 M –1 s –1 ) is at least 3–8 times greater than the rate of O 2 •– decomposition by superoxide dismutase, thus indicating that • NO has the ability to drive O 2 •– away from its main detoxification pathway. − …”

“…At physiological pH, the apparent half-life of ONOOH is approximately 1 s. ONOOH produces ∼70% nitrate (NO 3 – ) and H + and about 30% nitrogen dioxide and hydroxyl radicals ( • NO 2 and • OH, respectively) through homolysis of the O–O bond. Although the primary product is NO 3 – , secondary reactions involving • NO 2 and O 2 •– can also result in nitrite (NO 2 – ) and dioxygen (O 2 ). ,,, …”