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5. Antibacterial effect of myeloperoxidase against <em>Streptococcus mutans</em>.

Author

Tenovuo, Jorma, Anttila, Olli, Lumikari, Marianne, and Sievers, Gunnel

Subjects
SALIVA, STREPTOCOCCUS mutans, LEUKOCYTES, GINGIVAL fluid, ANTI-infective agents, MICROORGANISMS
Abstract

Myeloperoxidase-chloride-H2O2 antimicrobial system is an integral part of leukocyte defense against pathogenic microorganisms. The system is present in gingival crevicular fluid and in whole saliva and, thus, possibly contributes to the non-antibody defense in the human mouth. In fact, at physiological concentrations myeloperoxidase-C1--H2O2 system effectively killed Streptococcus mutans both at acid and neutral pH. However, thiocyanate (SCN-) ions at concentrations similar to those in human saliva abolished this bactericidal action indicating that SCN- rather than CI- is the physiologic substrate of myeloperoxidase in whole saliva. The peroxidation of SCN- (by myeloperoxidase or salivary peroxidase) yields oxidation products which inhibit the growth and metabolism of S. mutans without notable loss of cell viability. Our results suggest that the presence of SCN- in saliva protects human oral tissues (and bacteria) from highly cytotoxic oxidation products of CI- and, instead, bacteriostatic and non-toxic oxidation products of SCN- are generated. In the gingival crevices, however, the SCN-/CI- ratio may be too small for effective block of CI- oxidation by myeloperoxidase, and the oxidation products of Cl-, such as hypochlorite or hypochlorous acid, may contribute to the breakdown of periodontal tissues during inflammation. [ABSTRACT FROM AUTHOR]

Published
1988
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7. Conformations of Chlorophylls a and a′ and their Magnesium-Free Derivatives as Revealed by Circular Dichroism and Proton Magnetic Resonance

Author

Hynninen, Paavo H. and Sievers, Gunnel

Abstract

The electronic absorption (UV/VIS), circular dichroism (CD) and proton magnetic resonance (1H NMR) spectra have been recorded for C-10 epimeric chlorophylls a and a′, pheophytins a and a′ as well as pheophorbides a and a′. Although the epimers in each pair showed virtually identical UV/VIS spectra, their CD spectra were profoundly different and exhibited opposite signs at most wavelengths in the UV region. The differences were interpreted as arising, in part, from different C-10 configurations, and, in part, from conformational alterations induced by the steric strain in the crowded periphery of the macrocycle. The conformational alterations were also clearly indicated by the 1H NMR Δδ-values observed for the α,β and δ methine protons, the C-10 protons and most methyl group protons of the epimers in each pair. This was considered to imply changes in the geometry of the whole macrocycle. The Δδ-values were larger for the Mg-free epimers than for the chlorophyll epimers, which shows that the central Mg-atom makes the macrocycle more rigid. Correlations between the signs of the CD bands and configurations are discussed.

Published
1981
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8. Thin layer chromatography of free porphyrins

Author

Ellfolk, Nils and Sievers, Gunnel

Abstract

Thin layer chromatography procedures are described for the separation and identification of a number of porphyrin free acids. Dicarboxylic porphyrins have been separated on neutral plate in benzene−methanol−−formic acid and chloroform−methanol−formic a and on acidic plates in toluene−isopropanol, benzene−isopropanol and benzene−methanol.

Published
1966
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35. The Heterogeneity of Lactoperoxidase.

Author

Carlström, Anders, primary, Sievers, Gunnel, additional, Turtóczky, I., additional, Fedorcsák, I., additional, Hoffman, Ragnar A., additional, and Westerdahl, Anders, additional

Published
1965
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