Archives of Microbiology

, Volume 169, Issue 3, pp 225–230 | Cite as

Isolation and immunocytochemical location of the nitrite-oxidizing system in Nitrospira moscoviensis

  • E. Spieck
  • Silke Ehrich
  • Jens Aamand
  • Eberhard Bock
Original paper

Abstract

A membrane-associated nitrite-oxidizing system of Nitrospira moscoviensis was isolated from heat-treated membranes. The four major proteins of the enzyme fraction had apparent molecular masses of 130, 62, 46, and 29 kDa, respectively. The nitrite-oxidizing activity was dependent on the presence of molybdenum. In contrast to the nitrite oxidoreductase of Nitrobacter hamburgensis X14, the activity of the nitrite-oxidizing system of Ns. moscoviensis increased when solubilized by heat treatment. Electron microscopy of the purified enzyme revealed uniform particles with a size of approximately 7 × 9 nm. SDS-immunoblotting analysis of crude extracts showed that the monoclonal antibodies Hyb 153–3, which recognize the β-subunit of the nitrite oxidoreductase from Nitrobacter, reacted with a protein of 50 kDa in Ns. moscoviensis. This protein corresponded to the protein of 46 kDa of the purified enzyme and contained a b-type cytochrome. Using electron microscopic immunocytochemistry and the monoclonal antibodies Hyb 153–3, the nitrite-oxidizing system of Ns. moscoviensis was shown to be located in the periplasmic space. Here a periodic arrangement of membrane-associated particles was found on the outside of the cytoplasmic membrane in the form of a hexagonal pattern. It is supposed that these particles represent the nitrite-oxidizing system in Nitrospira.

Key wordsNitrospira moscoviensis Nitrite-oxidizing system Membrane-associated enzyme Periplasmic space Monoclonal antibodies Post-embedding labeling Hexagonal pattern 

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Copyright information

© Springer-Verlag Berlin Heidelberg 1998

Authors and Affiliations

  • E. Spieck
    • 1
  • Silke Ehrich
    • 1
  • Jens Aamand
    • 2
  • Eberhard Bock
    • 1
  1. 1.Institut für Allgemeine Botanik, Abteilung Mikrobiologie, Universität Hamburg, Ohnhorststrasse 18, D-22609 Hamburg, Germany Tel. +49-40-82282-426; Fax +49-40-82282-424 e-mail: spieck@mikrobiologie.uni-hamburg.deDE
  2. 2.Geological Survey of Denmark and Greenland, Department of Geochemistry, Thoravej 8, DK-2400 Copenhagen NV, DenmarkDK

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