The Effect of Transition Metal Ions on the Resistance of Bacterial Spores to Hydrogen Peroxide and to Heat

Transition metal ions present in pulp, cause wasteful decomposition of hydrogen peroxide, a pulp brightener, and thus significantly affect the delignification selectivity of hydrogen peroxide bleaching. The metal ions also affect the brightness and optical properties of pulp. The free radicals generated during the decomposition degrade carbohydrates resulting in lower viscosity and yield. It is reported in the literature that magnesium sulfate successfully adsorbs transition metal ions and thus decrease their activity. This study dealt with the effect of Mg salts in hydrogen peroxide bleaching of jute caddies pulp. It was observed that prior bleaching treatments like chelation and acid washing of pulp were efficient in removing transition metal ions as indicated by lower consumption of hydrogen peroxide. However EDTA chelation seemed better compared to acid washing. The inclusion of Mg salts improved pulp brightness. The pulp viscosity was the highest with 0.3% Mg addition for both treated kraft and soda-AQ pulps. Considering both pulp viscosity and pulp brightness, it appeared that a 0.3% Mg dose on EDTA chelated pulp, was enough in hydrogen peroxide bleaching of pulps obtained from jute caddies. Bangladesh J. Sci. Ind. Res. 51(4), 291-296, 2016

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DNA Oxidative Cleavage Induced by the Novel Peptide Derivatives of 3-(quinoxalin-6-yl)alanine in Combination with Cu(II) or Fe(II) Ions

Bioinorganic Chemistry and Applications ◽

10.1155/2009/906836 ◽

2009 ◽

Vol 2009 ◽

pp. 1-10 ◽

Cited By ~ 2

Author(s):

Wojciech Szczepanik ◽

Marzena Kucharczyk-Klamińska ◽

Piotr Stefanowicz ◽

Anna Staszewska ◽

Zbigniew Szewczuk ◽

...

Keyword(s):

Hydrogen Peroxide ◽

Dna Damage ◽

Transition Metal ◽

Metal Ions ◽

Transition Metal Ions ◽

Stable Complex ◽

The Novel ◽

Complex Species ◽

Peptide Derivatives ◽

Derivatives Of

Three model dipeptides containing 3-(2,3-di(pyridin-2-yl)quinoxalin-6-yl)alanine, 3-(dipyrido[3,2-a:2,3-c]phenazin-11-yl)alanine, and 3-(2,3-diphenylquinoxalin-6-yl)alanine were studied with respect to their ability to bind selected transition metal ions, such as Cu(II), Fe(II), Ni(II), Co(II), Mn(II), and Cr(III). It was found that only Cu(II) and Fe(II) ions could form stable complex species with the studied compounds. The ability to form the complexes correlated well with DNA damage experiments. Only the ferrous and cupric complexes are capable of generating both single- and double-strand scissions. However, double-strand breakages appear to be dominating lesions in the presence of hydrogen peroxide, especially for copper(II) containing systems. The quantity of breakage products in the presence ofN-(3-(dipyrido[3,2-a:2,3-c]phenazine-11-yl)alanyl)glycine complexes was the highest as compared to the complexes of the remaining compounds. Moreover, this ligand was the only one that cleaved DNA in the absence of either Cu(II) or Fe(II) ions.

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