Cocaine reduces macrophage killing by inhibiting reactive nitrogen intermediates

ABSTRACT The contribution of reactive oxygen intermediates (ROI) and reactive nitrogen intermediates (RNI) to the killing of Listeria monocytogenes by macrophages activated by addition of spleen cells from listeria-immune mice plus specific antigen was examined. When macrophages were infected with L. monocytogenes and then spleen cells were added, there was not as big a difference in listericidal activity between macrophages cultured with normal spleen cells and those cultured with immune spleen cells as expected. In this culture system, RNI was mainly involved in the macrophage intracellular killing. In macrophages first activated and then infected, a significant level of enhanced killing was observed. Blockade of ROI production drastically affected the enhanced killing ability, while inhibition of RNI production had a negligible effect. Thus, the contributions of ROI and RNI to listericidal mechanisms of macrophages were different between macrophages activated at pre- and postinfection stages.

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Reactive nitrogen intermediates in experimental trichomoniasis induced with isolates from symptomatic and asymptomatic women

Parasitology Research ◽

10.1007/s00436-004-1155-z ◽

2004 ◽

Cited By ~ 3

Author(s):

Nancy Malla ◽

Zarrintaj Valadkhani ◽

Kusum Harjai ◽

Saroj Sharma ◽

Indu Gupta

Keyword(s):

Reactive Nitrogen ◽

Reactive Nitrogen Intermediates ◽

Asymptomatic Women

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Reactive Nitrogen Intermediates in the Pathogenesis of Systemic Lupus Erythematosus

Systemic Lupus Erythematosus ◽

10.1016/b978-0-12-801917-7.00029-2 ◽

2016 ◽

pp. 243-253

Author(s):

Gary S. Gilkeson ◽

Jim C. Oates

Keyword(s):

Systemic Lupus Erythematosus ◽

Lupus Erythematosus ◽

Reactive Nitrogen ◽

Systemic Lupus ◽

Reactive Nitrogen Intermediates

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Polyamine-Mediated Resistance of Uropathogenic Escherichia coli to Nitrosative Stress

Journal of Bacteriology ◽

10.1128/jb.188.3.928-933.2006 ◽

2006 ◽

Vol 188 (3) ◽

pp. 928-933 ◽

Cited By ~ 39

Author(s):

Jean M. Bower ◽

Matthew A. Mulvey

Keyword(s):

Escherichia Coli ◽

Nitrosative Stress ◽

Resistance Mutation ◽

Reactive Nitrogen ◽

E Coli ◽

Exogenous Addition ◽

Reactive Nitrogen Intermediates ◽

Transposon Mutants ◽

Increased Sensitivity ◽

K 12

ABSTRACT During the course of a urinary tract infection, substantial levels of nitric oxide and reactive nitrogen intermediates are generated. We have found that many uropathogenic strains of Escherichia coli display far greater resistance to nitrosative stress than the K-12 reference strain MG1655. By selecting and screening for uropathogenic E. coli transposon mutants that are unable to grow in the presence of acidified nitrite, the cadC gene product was identified as a key facilitator of nitrosative stress resistance. Mutation of cadC, or its transcriptional targets cadA and cadB, results in loss of significant production of the polyamine cadaverine and increased sensitivity to acidified nitrite. Exogenous addition of cadaverine or other polyamines rescues growth of cad mutants under nitrosative stress. In wild-type cells, the concentration of cadaverine produced per cell is substantially increased by exposure to acidified nitrite. The mechanism behind polyamine-mediated rescue from nitrosative stress is unclear, but it is not attributable solely to chemical quenching of reactive nitrogen species or reduction in mutation frequency.

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