Porphyrin ring source can alter the outer membrane protein profile of non-typable Haemophilus influenzae

Maciver, Isobel; O'Reilly, T; Brown, M. R. W.

doi:10.1099/00222615-31-3-163

Cited by 8 publications

(8 citation statements)

References 21 publications

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“…directly into the cell (35). In addition to siderophores, several gram-negative species (i.e., Neisseria gonorrhoeae, Haemophilus influenzae, Bacteroides fragilis) (12,14,26,36,39,55) also express IBPs in their outer membranes. These IBPs function independently of the siderophores and sequester minute amounts of iron from the environment by interacting directly with the host IBPs (i.e., TF, LF, and HGB).…”

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confidence: 99%

Roles of porphyrins and host iron transport proteins in regulation of growth of Porphyromonas gingivalis W50

1991

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Porphyromonas gingivalis (Bacteroides gingivalis) requires iron in the form of hemin for growth and virulence in vitro, but the contributions of the porphyrin ring structure, porphyrin-associated iron, host hemin-sequestering molecules, and host iron-withholding proteins to its survival are unknown. Therefore, the effects of various porphyrins, host iron transport proteins, and inorganic iron sources on the growth of P. gingivalis W50 were examined to delineate the various types of iron molecules used for cellular metabolism. Cell envelope-associated hemin and iron stores contributed to the growth of P. gingivalis in hemin-free culture, and depletion of these endogenous reserves required eight serial transfers into hemin-free medium for total suppression of growth. Comparable growth of P. gingivalis was observed with 7.7 microM equivalents of hemin as hemoglobin (HGB), methemoglobin, myoglobin, hemin-saturated serum albumin, lactoperoxidase, cytochrome c, and catalase. Unrestricted growth was recorded in the presence of haptoglobin-HGB and hemopexin-hemin complexes, indicating that these host defense proteins do not sequester HGB and hemin from P. gingivalis. The iron chelator 2,2'-bipyridyl functionally chelated hemin-associated iron, resulting in dose-dependent inhibition of growth in hemin-restricted cultures at 1 to 25 microM 2,2'-bipyridyl concentrations. In the absence of an exogenous iron source, protoporphyrin IX did not support P. gingivalis growth. These findings suggest that the iron atom in the hemin molecule is the critical constituent for growth and that the tetrapyrrole porphyrin ring structure may represent an important vehicle for delivery of iron into the P. gingivalis cell. P. gingivalis does not have a strict requirement for porphyrins, since growth occurred with nonhemin iron sources, including high concentrations (200 muM) of ferric, ferrous, and nitrogenous inorganic iron, and P. gingivalis exhibited unrestricted growth in the presence of host transferrin, lactoferrin, and serum albumin. The diversity of iron substrates utilized by P. gingivalis and the observation that growth was not affected by the bacteriostatic effects of host iron-withholding proteins, which it may encounter in the periodontal pocket, may explain why P. gingivalis is such a formidable pathogen in the periodontal disease process.

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confidence: 99%

Roles of porphyrins and host iron transport proteins in regulation of growth of Porphyromonas gingivalis W50

1991

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“…The levels of both Tbp1 and Tbp2 markedly diminish as the concentration of PPIX is increased such that no Tbps are affinity purified from cells grown in NRPMI containing around 10 μM PPIX (data not shown). Although these results were unexpected, growth of H. influenzae in BHI containing PPIX rather than haem has previously been shown to lead to alterations in the outer membrane protein profiles and the appearance of novel but as yet uncharacterised polypeptides [9, 10].…”

Section: Resultsmentioning

confidence: 95%

Elemental iron does repress transferrin, haemopexin and haemoglobin receptor expression in Haemophilusinfluenzae

Hasan

Holland

Smith

et al. 2006

FEMS Microbiology Letters

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The iron repressible nature of Haemophilus influenzae transferrin binding proteins suggests a regulatory role for elemental iron in their expression. The existence of a Haemophilus ferric uptake repressor (Fur) binding motif identified in the promoter region of both tbpA and tbpB further supports this hypothesis. However, a recent study using brain heart infusion growth medium suggested that transferrin binding protein synthesis in H. influenzae was haem-rather than iron-regulated. The present study re-investigates this observation and using a chemically defined medium, we demonstrate that elemental iron haem or protoporphyrin IX can each regulate Haemophilus influenzae transferrin, haemopexin and haemoglobin receptor expression.

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“…(E) Hemin (7.0 WM, ¢nal concentration); (O) protoporphyrin IX (7.0 WM, ¢nal concentration) ; (7) protoporphyrin IX-zinc (7.0 WM, ¢nal concentration); (a) THBM^BPD (no supplements). malian heme synthesis, is a physiological substrate [28]? While we are not certain about the implications of P. intermedia of possessing a putative ferrochelatase, it is possible, as suggested by Loeb [31], that ferrochelatase might function in the reverse reaction in vivo by extracting the ferrous iron out of uptaken hemoglobin or heme, enabling the cells to obtain iron from the host.…”

Section: Resultsmentioning

confidence: 99%

Effects of porphyrins and inorganic iron on the growth of Prevotella intermedia

Leung

2002

FEMS Microbiology Letters

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We demonstrated earlier that hemin^iron-containing compounds which include hemin, human hemoglobin, bovine hemoglobin, and bovine catalase stimulate the growth of Prevotella intermedia [Leung, Subramaniam, Okamoto, Fukushima, Lai, FEMS Microbiol. Lett. 162 (1998) 227^233]. However, the contributions of tetrapyrrole porphyrin ring in these hemin^iron sources as well as inorganic iron for the growth of this organism have not been determined. The purpose of this study was to examine the effects of porphyrins, host ironbinding proteins, and various inorganic iron sources on the growth of hemin^iron depleted P. intermedia. Protoporphyrin IX and protoporphyrin IX-zinc, either in the presence or absence of supplemented ferrous or ferric iron, promoted the growth of P. intermedia at a rate that was comparable to that of the hemin control. On the other hand, neither the host iron proteins, transferrin and lactoferrin, nor the inorganic iron sources which included ferrous chloride, ferric chloride, ferric citrate, ferric nitrate, and ferric ammonium citrate at concentrations up to 200 WM stimulated the growth of hemin^iron-restricted P. intermedia. The results suggest that P. intermedia only use iron in a specific form and that the porphyrin-ring structure is essential for the growth of P. intermedia as in the case of other related organisms. ß

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Porphyrin ring source can alter the outer membrane protein profile of non-typable Haemophilus influenzae

Cited by 8 publications

References 21 publications

Roles of porphyrins and host iron transport proteins in regulation of growth of Porphyromonas gingivalis W50

Roles of porphyrins and host iron transport proteins in regulation of growth of Porphyromonas gingivalis W50

Elemental iron does repress transferrin, haemopexin and haemoglobin receptor expression in Haemophilusinfluenzae

Effects of porphyrins and inorganic iron on the growth of Prevotella intermedia

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