The blue dissimilatory nitrite reductase (NiR) from Alcaligenes xylosoxidans is a trimer containing two types of Cu centre, three type 1 electron transfer centres and three type 2 centres. The latter have been implicated in the binding and reduction of nitrite. The Cu ion of the type 2 centre of the oxidized enzyme is ligated by three His residues, and additionally has a co-ordinated water mole...

the fruit of melia azedarach l. (meliaceae) was extracted with hexane, and its fatty acids methyl ester was analyzed using gc/ms. thirteen components representing 85.1% of the total extract were identified. the major components identified were methyl palmitate (18.8%), methyl linolenate (16.1%) and methyl linoleate (9.8%). the fruits’ extract had a lc50 of 5.5 ppm against the larvae of anophles...

Cryptococcus neoformans is an opportunistic fungus that causes life-threatening meningoencephalitis in 5-10% of patients with acquired immune deficiency syndrome. Cryptococcal meningoencephalitis is characterized by a lymphohistiocytic infiltrate, accumulation of encapsulated forms of C. neos6rmans, and varying degrees of glial reaction. Little is known about the contribution of endogenous cent...

Hydroxylamine has been determined by its oxidation to nitrite with a known excess of bromine. Bromine in acidic medium bleaches the dye methyl red. A known excess of bromine when treated with hydroxylamine is reduced to bromide and the unreacted bromine is determined using methyl red. The method obeys Beer’s law in the range 0-5 μg of hydroxylamine in an overall aqueous volume of 25 mL. The rel...

A kinetic spectrophotometric method for measuring thiocyanate is described. The proposed method is based on the inhibitory effect of thiocyanate on the oxidation of Methyl Red by bromate in the presence of nitrite, which was monitored at 520 nm. The variables affecting the rate of the reaction were investigated and the optimum conditions were established. Thiocyanate can be measured in the rang...

The mechanism of the nitrosation of enolate anion of acetone [CH3COCH2]- (1) with methyl nitrite CH3ONO (2) via an "open-chain" transition state without Na+ in the C-N bond formation process was studied by the ab initio MO method. The complex [CH3COCH2NO(OCH3)]- (C-II) was first formed from the adduct (C-I) of 1 and 2 through the transition state (TSI). Finally, E-1-hydroxyimino-2-oxo-propane C...

This study examined the production of nitric oxide (NO) in the renal cortex and medulla through the use of an in vivo microdialysis technique. Oxyhemoglobin (OxyHb) at a concentration of 3 mumol/L was perfused through the dialysis system to trap tissue NO. Methemoglobin (MetHb), which was formed by NO oxidation of OxyHb in the dialysate, was spectrophotometrically assayed at 401 nm. Because the...

Methane oxidation is an important process to mitigate the emission of the greenhouse gas methane and further exacerbating of climate forcing. Both aerobic and anaerobic microorganisms have been reported to catalyze methane oxidation with only a few possible electron acceptors. Recently, new microorganisms were identified that could couple the oxidation of methane to nitrate or nitrite reduction...

The goal of the present study was to examine the effectiveness of a non-specific nitric oxide synthase (NOS) inhibitor N-nitro-L-arginine methyl ester (L-NAME) to modulate the toxicity of aluminium chloride (AlCl3). Rats were killed at 3 h and at 30 days after treatments and the striatum was removed. Nitrite, superoxide, superoxide dismutase activity, malondialdehyde and reduced glutathione wer...

Nitric oxide (NO) derived from endothelial NO synthase (NOS) (eNOS) has been identified as a trigger for the second window of protection (SWOP), but its role as a mediator during the SWOP is a matter of debate. Eighteen mongrel dogs were chronically instrumented to measure left ventricular function, coronary blood flow, and wall thickening. Myocardial preconditioning was induced by 10 min coron...