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Subject: syphilis

   Genitourin Med 1988 Dec;64(6):359-63
   
Affinities of Treponema pallidum for human lactoferrin and transferrin.

    Alderete JF, Peterson KM, Baseman JB
    
   Department of Microbiology, University of Texas Health Science Center,
   San Antonio 78284-7758.
   
   The acquisition of lactoferrin and transferrin by live Treponema
   pallidum organisms was examined. Saturation binding kinetics were
   obtained for virulent treponemes with increasing amounts of
   radioiodinated lactoferrin but not with transferrin. Furthermore,
   lactoferrin bound up to 100 times more effectively than transferrin.
   Only unlabelled lactoferrin stoichiometrically completed with
   iodinated lactoferrin binding. Time course kinetics showed maximum
   lactoferrin acquisition within the first five minutes at 34 degrees C.
   Optimum iron accumulation, however, was achieved by T pallidum in 30
   minutes at 34 degrees C, and amounts of iron were six times greater
   than the equivalent amount of lactoferrin bound. Interestingly, iron
   uptake was also detected in the presence of transferrin, despite the
   minimal amounts of transferrin acquired by live treponemes. These
   observations reinforce the possibility that the associations of T
   pallidum with host molecules, such as plasma proteins, are essential
   for survival of the parasite within host environments.
   
   PMID: 3066739, UI: 89138411
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Subject: Iron and bacteria


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   J Clin Invest 61: 1428-40 (1978)[78194498]

The critical role of iron in host-bacterial interactions.



    S. M. Payne & R. A. Finkelstein



   The ability of potential pathogens to acquire iron in a host is an
   important determinant of both their virulence and the nature of the
   infection produced. Virulent gram-negative bacteria are capable of
   acquiring sufficient iron from the host because their virulence (for
   chick embryos) is unaffected by exogenous iron. Avirulent mutants
   which are apparently limited in their ability to acquire iron could be
   isolated from the virulent strains. The lethality of these mutants was
   significantly enhanced by exogenous iron. Reduction of the relatively
   high serum iron saturation of chick embryos (to levels more closely
   approximating those in man) by pretreatment with iron-binding proteins
   or endotoxin inhibits the lethality of some virulent bacteria. Those
   bacteria whose virulence was reduced include the Shigella, Vibrio
   cholerae and strains of Neisseria gonorrhoeae, all of which are
   nondisseminating pathogens in the normal human host. Pathogens which
   produce septicemic and disseminating infections such as Neisseria
   meningitidis, Haemophilus influenzae type B, Escherichia coli
   possessing K-1 antigen, Pseudomonas aeruginosa and Salmonella
   typhimurium and disseminating strains of N. gonorrhoeae were, in
   general, unaffected by reduced serum iron saturation. These
   disseminating bacteria appeared to produce greater quantities of
   compounds (siderophores) which stimulated microbial growth in low-iron
   media than did the nondisseminating pathogens. Thus, the gram-negative
   bacteria tested can be divided into four major classes according to
   their responses to modifications in iron levels in the chick embryo
   model and these results correlate with the nature of the infections
   which they typically produce in man.

   MeSH Terms:
     * Animal
     * Bacteria/drug effects
     * Bacteria/metabolism
     * Bacteria/pathogenicity
     * Bacterial Infections/immunology
     * Bacterial Infections/metabolism
     * Chick Embryo
     * Conalbumin/pharmacology
     * Iron/metabolism
     * Iron/pharmacology
     * Iron Chelates/metabolism
     * Support, U.S. Gov't, P.H.S.


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