Nitric oxide (NO) stimulated the activity of plasma membrane H+-ATPase, 5'-nucleotidase, peroxidase, ascorbate peroxidase and glutathione reductase in ultraviolet B (UV-B) irradiated Chlorella pyrenoidosa. It also boosted the activity of nitrogen-metabolism enzymes such as nitrate reductase, nitrite reductase, glutamine synthetase, which were inhibited by UV-B irradiation. The chlorophyll fluorescence ratio (Fv/Fm) of the UV-B irradiated algae and decreased continuously after the cells were transferred to UV-B irradiation. A continuing decrease of the Fv/Fm was observed even after the cells were transferred to photosynthetically active radiation (PAR). After adaptation for 8 h under PAR (after treatment with nitric oxide), Fv/Fm recovered to 55 % of normal levels--without NO the value approached zero. Exogenous NO stopped the decay of chlorophyll and thylakoid membrane in cells exposed to UV-B irradiation. NO plays probably a key role in damage induced by UV-B irradiation in green algae.

• MeSH
• Algal Proteins metabolism   MeSH
• Cell Membrane enzymology   MeSH
• Chlorella physiology   radiation effects   MeSH
• Enzymes metabolism   MeSH
• Nitric Oxide physiology   MeSH
• Second Messenger Systems * MeSH
• Ultraviolet Rays * MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• Algal Proteins MeSH
• Enzymes MeSH
• Nitric Oxide MeSH

The effect of ultraviolet-B radiation (UV-B; 280-320 nm) on induction of nitric oxide was estimated in the suspensions of green alga Chlorella pyrenoidosa with or without the NO scavenger N-acetyl-L-cysteine, and reductants such as 1,4-dithiothreitol, glutathione (reduced form), and ascorbic acid. Exogenously added sodium nitroprusside (NO donor), glutathione, 1,4-dithiothreitol, and ascorbic acid were able to prevent chlorophyll loss mediated by UV-B. Addition of NO to algal suspensions irradiated by UV-B increased the activity of catalase and superoxide dismutase but lowered the activity of phenylalanine ammonia-lyase. UV-B thus appears to be a strong inducer of NO production, exogenously added NO and reductants protecting the green alga against UV-B-induced oxidative damage.

• MeSH
• Acetylcysteine pharmacology   MeSH
• Chlorella enzymology   metabolism   radiation effects   MeSH
• Chlorophyll metabolism   MeSH
• Dithiothreitol pharmacology   MeSH
• Phenylalanine Ammonia-Lyase metabolism   MeSH
• Glutathione pharmacology   MeSH
• Catalase metabolism   MeSH
• Ascorbic Acid pharmacology   MeSH
• Nitroprusside pharmacology   MeSH
• Nitric Oxide biosynthesis   MeSH
• Oxidative Stress drug effects   physiology   MeSH
• Superoxide Dismutase metabolism   MeSH
• Ultraviolet Rays adverse effects   MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• Acetylcysteine MeSH
• Chlorophyll MeSH
• Dithiothreitol MeSH
• Phenylalanine Ammonia-Lyase MeSH
• Glutathione MeSH
• Catalase MeSH
• Ascorbic Acid MeSH
• Nitroprusside MeSH
• Nitric Oxide MeSH
• Superoxide Dismutase MeSH

Reactive NO metabolites play a distinct role in the control of Salmonella enterica serovar Typhimurium (ST; a facultative intracellular pathogen) in susceptible host. A significant increase of nitrite and/or nitrate plasma levels, 3-nitro-tyrosine expression and pathological changes in mesenteric lymph nodes have been observed in gnotobiotic piglets orally infected for 1 d with a virulent strain of ST but not in piglets infected with a rough mutant of ST.

• MeSH
• Microscopy, Electron MeSH
• Phagocytosis MeSH
• Germ-Free Life MeSH
• Immunoenzyme Techniques MeSH
• Liver ultrastructure   MeSH
• Lymph Nodes metabolism   ultrastructure   MeSH
• Mesentery MeSH
• Swine, Miniature MeSH
• Nitric Oxide metabolism   MeSH
• Lung ultrastructure   MeSH
• Swine MeSH
• Salmonella typhimurium pathogenicity   MeSH
• Salmonella Infections, Animal immunology   metabolism   microbiology   pathology   MeSH
• Intestines ultrastructure   MeSH
• Tyrosine analogs & derivatives   metabolism   MeSH
• Virulence MeSH
• Animals MeSH
• Check Tag
• Animals MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• 3-nitrotyrosine MeSH Browser
• Nitric Oxide MeSH
• Tyrosine MeSH

Mycobacterium microti-infected mouse peritoneal macrophages produced high amounts of prostaglandin E2 (PGE2) and nitric oxide (NO) when activated with interferon-gamma (IFN-gamma). In order to understand the relation between PGE2 and NO production and the expression of interleukin-12 (IL-12), interleukin-10 (IL-10) and MHC class-II (Ia) molecules by M. microti-infected and IFN-gamma-stimulated macrophages, we analyzed the level of these molecules in the presence or absence of PGE2 and NO inhibitors. Addition of NG-methyl-L-arginine (L-NMA) and indomethacin (IM) caused a significant increase in IL-12 level (2.6- and 1.9-fold, respectively) whereas IL-10 level decreased by 88 and 56%, respectively, relative to M. microti-infected and IFN-gamma-treated control macrophages. Enhanced PGE2 and NO upregulated IL-10 expression and down-regulated IL-12 and MHC class-II (Ia) expression in M. microti-infected and IFN-gamma-treated mouse peritoneal macrophages.

• MeSH
• Dinoprostone antagonists & inhibitors   metabolism   MeSH
• Indomethacin pharmacology   MeSH
• Cyclooxygenase Inhibitors pharmacology   MeSH
• Interferon-gamma pharmacology   MeSH
• Interleukin-10 biosynthesis   MeSH
• Interleukin-12 biosynthesis   MeSH
• Histocompatibility Antigens Class II biosynthesis   MeSH
• Mycobacterium Infections immunology   metabolism   MeSH
• Mice, Inbred BALB C MeSH
• Mice MeSH
• omega-N-Methylarginine pharmacology   MeSH
• Nitric Oxide antagonists & inhibitors   metabolism   MeSH
• Macrophages, Peritoneal drug effects   metabolism   microbiology   MeSH
• Antineoplastic Agents pharmacology   MeSH
• Teprotide pharmacology   MeSH
• Animals MeSH
• Check Tag
• Mice MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• Dinoprostone MeSH
• Indomethacin MeSH
• Cyclooxygenase Inhibitors MeSH
• Interferon-gamma MeSH
• Interleukin-10 MeSH
• Interleukin-12 MeSH
• Histocompatibility Antigens Class II MeSH
• omega-N-Methylarginine MeSH
• Nitric Oxide MeSH
• Antineoplastic Agents MeSH
• Teprotide MeSH

A comparative study was done using J774A.1 and J774A.1-derived transfected cells (J774A.1 C.1) containing antisense tumor necrosis factor alpha (TNF-alpha) plasmid to determine the role of endogenous TNF-alpha on nitric oxide production as well as on the growth of Mycobacterium microti in interferon gamma (IFN-gamma)- and lipopolysaccharide (LPS)-treated cells. On stimulation with IFN-gamma and LPS a higher level of NO was observed in J774A.1 cells compared to J774A.1 C.1 which indicated that endogenous TNF-alpha is required for the production of NO. Comparing the effect of IFN-gamma and LPS on the intracellular growth of M. microti, the growth-reducing activity was higher in J774A.1 cells than in J774A.1 C.1 cells and was not completely abrogated in the presence of the nitric oxide inhibitor NG-methyl-L-arginine (L-NMA). J774A.1 C.1 cells infected with M. microti produced a significant amount of NO when exogenous TNF-alpha was added along with IFN-gamma and LPS and the concentration of intracellular bacteria decreased almost to that in IFN-gamma and LPS treated parental J774A.1 cells. Addition of exogenous TNF-alpha even in the presence of L-NMA in J774A.1 C.1 cells could also partially restore intracellular growth inhibition of M. microti caused by IFN-gamma and LPS. TNF-alpha is probably required for the production of NO in J774A.1 cells by IFN-gamma and LPS but TNF-alpha and NO are independently involved in the killing of intracellular M. microti with IFN-gamma and LPS.

• MeSH
• Macrophage Activation drug effects   MeSH
• Cell Line MeSH
• Interferon-gamma pharmacology   MeSH
• Lipopolysaccharides pharmacology   MeSH
• Macrophages drug effects   immunology   microbiology   MeSH
• Mycobacterium growth & development   pathogenicity   MeSH
• Mycobacterium Infections microbiology   MeSH
• Mice MeSH
• Nitric Oxide biosynthesis   MeSH
• Plasmids MeSH
• Colony Count, Microbial MeSH
• Nitric Oxide Synthase Type II MeSH
• Nitric Oxide Synthase metabolism   MeSH
• Tumor Necrosis Factor-alpha biosynthesis   MeSH
• Transfection MeSH
• Animals MeSH
• Check Tag
• Mice MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Comparative Study MeSH
• Names of Substances
• Interferon-gamma MeSH
• Lipopolysaccharides MeSH
• Nos2 protein, mouse MeSH Browser
• Nitric Oxide MeSH
• Nitric Oxide Synthase Type II MeSH
• Nitric Oxide Synthase MeSH
• Tumor Necrosis Factor-alpha MeSH

Peroxynitrite was tested for its effects on the opportunistic pathogenic fungus Aspergillus fumigatus. It did not kill any dormant or swollen (4 h in a glucose-peptone medium) conidia in concentrations up to 6.25 mmol/L and the growth of germlings (after 6 or 9 h) was only slightly inhibited by 5 mmol/L peroxynitrite. The peroxynitrite donor SIN-1 (up to 10 mmol/L, 1 d in buffer) did not kill any conidia but inhibited their germination and growth, depending on the medium. Ten mmol/L SIN-1 in a poor medium was fungistatic and germination was stopped for 20 h. Nine strains of A. fumigatus showed resistance comparable to the model strain, while 6 Candida albicans strains were much more susceptible to both peroxynitrite and its donor. The results indicate that peroxynitrite does not contribute substantially to the antifungal activity of phagocytes against A. fumigatus.

• MeSH
• Aspergillus fumigatus drug effects   physiology   MeSH
• Aspergillosis microbiology   MeSH
• Time Factors MeSH
• Nitric Oxide Donors pharmacology   MeSH
• Nitrates pharmacology   MeSH
• Chickens MeSH
• Humans MeSH
• Oxidants pharmacology   MeSH
• Spores, Fungal drug effects   MeSH
• Dose-Response Relationship, Drug MeSH
• Animals MeSH
• Check Tag
• Humans MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Comparative Study MeSH
• Names of Substances
• Nitric Oxide Donors MeSH
• Nitrates MeSH
• Oxidants MeSH
• peroxynitric acid MeSH Browser