Infection and Immunity, November 1998, p. 5215-5223, Vol. 66, No. 11
0019-9567/98/$04.00+0
Copyright © 1998, American Society for Microbiology. All rights reserved.
Department of Medicine,
Received 29 April 1998/Returned for modification 12 June
1998/Accepted 29 July 1998
Many bacterial pathogens, including pathogenic neisseriae, can use
heme as an iron source for growth. To study heme utilization by
Neisseria gonorrhoeae, two heme biosynthetic mutants were
constructed, one with a mutation in hemH (the gene encoding
ferrochelatase) and one with a mutation in hemA (the gene
encoding
-glutamyl tRNA reductase). The hemH mutant
failed to grow without an exogenous supply of heme or hemoglobin,
whereas the hemA mutant failed to grow unless heme,
hemoglobin, or heme precursors were present. Growth of the mutants with
hemoglobin required expression of the hemoglobin receptor (HpuAB) and
was TonB dependent. However, growth with heme required neither HpuAB
nor TonB. An fbpA mutant grew normally when either heme or
hemoglobin was present in the medium. The heme biosynthetic mutants
showed reduced intracellular survival, compared to the parent strain,
within A-431 endocervical epithelial cell cultures. These studies
demonstrate that in addition to synthesizing their own heme, N. gonorrhoeae strains are able to internalize and utilize exogenous
heme independently of FbpA but appear unable to obtain heme from within
epithelial cells for growth.
*
Corresponding author. Mailing address: Department of
Medicine, Division of Infectious Diseases, University of North Carolina at Chapel Hill, 521 Burnett-Womack Bldg., CB 7030, Chapel Hill, NC
27599. Phone: (919) 966-3661. Fax: (919) 966-6714. E-mail: pturner{at}med.unc.edu.
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