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Nitrite
About: Nitrite is a research topic. Over the lifetime, 15425 publications have been published within this topic receiving 484581 citations.
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TL;DR: Nitrospira seems to be not only a common aquatic but also a usual soil bacterium, which could be clearly identified in enrichment cultures derived from freshwater marsh and from permafrost soil.
Abstract: Chemolithotrophic nitrite oxidizers were enriched from five different soils including freshwater marsh, permafrost, garden, agricultural, and desert soils and monitored during the cultivation procedure. Immunoblot analysis was used to identify the nitrite oxidizing organisms with monoclonal antibodies, which recognize the key enzyme of nitrite oxidation in a genus-specific reaction [Bartosch et al. (1999) Appl Environ Microbiol 65:4126-4133]. The morphological characteristics of the enriched nitrite oxidizers were additionally studied using transmission electron microscopy (TEM) and fluorescence microscopy. By means of the antibodies and TEM analysis Nitrospira could be clearly identified in enrichment cultures derived from freshwater marsh and from permafrost soil. Nitrospira cells were enriched simultaneously with cells of the genus Nitrobacter when nitrite concentrations of 0.2 g of NaNO 2 L -1 were used. However, in enrichment cultures containing 2 g of NaNO 2 L -1 Nitrobacter was exclusively detected. During fluorescence microscopic observations of DAPI stained samples microcolonies were found in enrichment cultures from freshwater marsh, permafrost, garden, and agricultural soil. They had a similar morphology to Nitrospira-like microcolonies from activated sludge. In conclusion, Nitrospira seems to be not only a common aquatic but also a usual soil bacterium.
110 citations
TL;DR: Nitrite inhibited active transport of proline in Escherichia coli but not group translocation of sugar via the phosphoenolpyruvate:phosphotransferase system, which indicated that nitrite has more than one site of attack in the bacterial cell.
Abstract: Nitrite inhibited active transport of proline in Escherichia coli but not group translocation of sugar via the phosphoenolpyruvate:phosphotransferase system. These results were consistent with previous results that nitrite inhibits active transport, oxygen uptake, and oxidative phosphorylation in aerobic bacteria. Nitrite also inhibited aldolase (EC 4.1.2.13) from E. coli, Pseudomonas aeruginosa, Streptococcus faecalis, and rabbit muscle. Thus, these various data showed that nitrite has more than one site of attack in the bacterial cell. These data also indicated that nitrite is inhibitory to a wide range of physiological types of bacteria.
110 citations
TL;DR: Channel catfish fingerlings exposed to 1.0, 2.5, and 5.0 mg/L nitrite for 5 h developed 42.5 ± 3.8% methemoglobin, which is close to normal for channel catfish exposed to nitrite, and when transferred to water containing 5 µm nitrite and 250‵m sodium chloride, meethemoglobin levels returned to normal within 24’h.
Abstract: Exposure of channel catfish (Ictalurus punctatus) fingerlings for 24 h to 1.0, 2.5, and 5.0 mg/L nitrite (pH = 7; hardness = 40 mg/L; temperature = 22–25 °C) produced methemoglobin levels of 20.7 ± 1.9%, 59.8 ± 1.9%, and 77.4 ± 1.4% (SE), respectively. However, methemoglobin levels were not elevated when fish were simultaneously exposed to 1.0, 2.5, and 5.0 mg/L nitrite and 25, 50, and 100 mg/L sodium chloride, respectively. Acclimation to sodium chloride for 24 h before exposure to nitrite did not enhance the inhibitory action of sodium chloride. Fish exposed to 5 mg/L nitrite for 5 h developed 42.5 ± 3.8% methemoglobin. When transferred to water containing 5 mg/L nitrite and 250 mg/L sodium chloride, methemoglobin levels returned to normal within 24 h. Environmental chloride probably inhibits methemoglobin formation by competing with nitrite for entrance into the gills of the fish. An ionic ratio of 16 Cl− to 1 NO2− is capable of complete suppression of nitrite-induced methemoglobin formation. Bicarbona...
110 citations
TL;DR: In Escherichia coli and Proteus morganii, the nitrosating activity was markedly induced when bacteria were cultured under anaerobiosis in minimal medium containing nitrate, while in the presence of nitrite there was no induction.
Abstract: SUMMARY: Biochemical, microbiological and genetic studies were done to characterize the mechanism of bacterial formation of N-nitrosomorpholine (NMOR) from morpholine and nitrite at neutral pH. In Escherichia coli and Proteus morganii, the nitrosating activity was markedly induced when bacteria were cultured under anaerobiosis in minimal medium containing nitrate, while in the presence of nitrite there was no induction. However, induction of the nitrosating activity in Pseudomonas aeruginosa occurred in anaerobic cultures in the presence of either nitrate or nitrite. The nitrosation capacity was also examined in various E. coli K12 mutants whose structural gene of either nitrate reductase or nitrite reductase was deleted. Nitrosation was not linked to the three (NADH-, formate- and glucose-dependent) nitrite reductases but was directly dependent on the presence of a nitrate reductase.
110 citations
TL;DR: An accurate and sensitive method is described by which nitrate and nitrite are extracted from food samples, then analyzed by ion chromatography (IC); commercial samples of ham and salami were analyzed by IC with UV absorbance detection.
110 citations