World Journal of Microbiology and Biotechnology

, Volume 13, Issue 2, pp 153–157

Cellular mechanisms of pH tolerance in Rhizobium loti

  • O.S. Correa
  • A.J. Barneix

DOI: 10.1023/A:1018577411631

Cite this article as:
Correa, O. & Barneix, A. World Journal of Microbiology and Biotechnology (1997) 13: 153. doi:10.1023/A:1018577411631


Seven strains of Rhizobium loti were tested for acid tolerance in yeast-extract mannitol (YEM) broth at pH values ranging from 4.0 to 8.0. The strains that grew at pH 4.0 showed the slowest generation time when grown at pH above 7.0 and also produced the most acid. The acid tolerance was related to the composition and structure of the membrane. pH influenced protein expression in acid-tolerant strains growing at pH 4.0 or 7.0. Acid tolerant strains showed one membrane protein of 49.5 kDa and three soluble proteins of 66.0, 58.0 and 44.0kDa; their expression increased when the cells grew at pH 4.0. It is suggested that acid tolerance in Rhizobium loti involves constitutive mechanisms, such as permeability of the outer membrane together with adaptive responses, including the state of bacterial growth and concomitant changes in protein expression.

Cellular mechanisms pH tolerance Rhizobium loti 

Copyright information

© Chapman and Hall 1997

Authors and Affiliations

  • O.S. Correa
    • 1
  • A.J. Barneix
    • 1
  1. 1.Ca´tedra de Microbiologi´a Agri´cola, Facultad de Agronomi´aUniversidad de Buenos AiresBuenos AiresArgentina ; fax

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