No abstract

A bacterial strain 5HP capable of degrading and utilizing 5-hydroxypicolinic acid as the sole source of carbon and energy was isolated from soil. In addition, the isolate 5HP could also utilize 3-hydroxypyridine and 3-cyanopyridine as well as nicotinic, benzoic and p-hydroxybenzoic acids for growth in the basic salt media. On the basis of 16S rRNA gene sequence analysis, the isolate 5HP was shown to belong to the genus Pusillimonas. Both the bioconversion analysis using resting cells and the enzymatic assay showed that the degradation of 5-hydroxypicolinic acid, 3-hydroxypyridine and nicotinic acid was inducible and proceeded via formation of the same metabolite, 2,5-dihydroxypyridine. The activity of a novel enzyme, 5-hydroxypicolinate 2-monooxygenase, was detected in the cell-free extracts prepared from 5-hydroxypicolinate-grown cells. The enzyme was partially purified and was shown to catalyze the oxidative decarboxylation of 5-hydroxypicolinate to 2,5-dihydroxypyridine. The activity of 5-hydroxypicolinate 2-monooxygenase was dependent on O2, NADH and FAD.

The electrochemical conversion of N-substituted phenoxazines (NSPs) bearing a CH 2 CH 2 ÀX substitute (where X¼OH, COOH, CH 2 NH 2 , CH 2 SO 3 H, CH 2 NHCOR) was investigated using cyclic voltammetry on a bulk gold electrode and a thin-layer spectroelectrochemical cell. The electrochemical oxidation of NSPs on the gold electrode was quasi-reversible and proceeded in a diffusion-controlled regime. The formal redox potential of NSPs covered the range from 0.39 to 0.45 V vs. SCE. The electrochemical oxidation of NSPs in the thin-layer spectroelectrochemical cell produced radical cations that showed absorbance at 385, 410 and 530 nm. Electrochemical conversion fitted the general voltammetric current-potential equation of a reversible wave, whereas electrolysis at constant potential showed a typical Cottrell behavior. Combining of NSPs with a biologically-relevant theophylline molecule did not change electrochemical and spectral properties of the phenoxazine core. Theophylline enlarged with NSPs demonstrated electrochemical and biocatalytic behavior similar to that of NSPs. The investigated NSPs possess electrochemical and spectral properties that are useful as biomolecular labels for electroanalysis.

ABSTRACT:The novel 4H-thiazolo[3,2-d]

[2,3-g] or [2,3-h]quinoline derivatives were prepared from 7-(or 8, or 9)amino-1,5-benzodiazepin-2-ones by the Doebner-von Miller quinoline synthesis. The structure of the cyclized products depends on the position of the primary amino group and on the substituents of the diazepine ring of the starting compounds. The regiochemical outcome of the reaction was estimated by calculating average local ionization energies on the molecular surface at the Density Functional Theory (DFT) level of theory.