Effect of concentration of compounds containing iron on the growth ofPorphyromonas gingivalis

Abstract

We examined the effect of the concentration of various types of iron molecules on the regulation of growth of Porphyromonas gingivalis. Bacterial growth was monitored spectrophotometrically. The hemin-depleted cells of P. gingivalis 381 were incubated in the basal medium plus test substrates such as hemoglobin, hemin, transferrin and various inorganic iron compounds. The relationship between the specific growth rate of organisms and the concentration of iron-containing compounds was determined. The value of Ks, a parameter analogous to the Michaelis-Menten constant, was estimated. P. gingivalis 381 showed a Ks value of 3.85, 4.91 and 0.0017 microM for hemin, transferrin and hemoglobin, respectively. However, the inorganic iron compounds tested did not support growth of P. gingivalis. These findings suggest that P. gingivalis utilizes hemoglobin as an iron source much more effectively than other iron-containing compounds under an iron-limited environment.

Characterization of a Hemophore-like Protein from Porphyromonas gingivalis

“…However, P. gingivalis does not produce siderophores or ferric reductases. Although P. gingivalis employs the Feo system to uptake ferrous iron in anaerobic or microaerophilic environments (40), growth studies have shown that P. gingivalis preferentially acquires iron in the form of heme rather than from other sources (9,41). For P. gingivalis, heme is also an essential nutrient source of protoporphyrin IX because the organism lacks the capacity to synthesize the porphyrin macrocycle de novo (2).…”

“…Compared with other hemoproteins, hemoglobin is utilized more efficiently by P. gingivalis under heme-limiting conditions (41). The concentration of heme in healthy gingival fluid is low (57), and the ability to scavenge heme from limited hemoproteins, particularly hemoglobin, appears to be critical for the colonization of this organism in vivo.…”

Human Lactoferrin Binds and Removes the Hemoglobin Receptor Protein of the Periodontopathogen Porphyromonas gingivalis

“…The concentrations of hemin and hemoglobin to support 50% of the maximal growth rates are 1-5 M and 1.7 nM, respectively (37), which implies that the iron uptake/utilization systems from hemin and hemoglobin may have, at least in part, different pathways. In a previous study (11), we presented a hypothetical mechanism of the iron uptake/utilization from erythrocytes.…”

“…Effect of Haptoglobin on the Binding of Hemoglobin to HbRHaptoglobin has the ability to bind hemoglobin (36) and suppress the growth of P. gingivalis in a medium containing hemoglobin (37). To determine whether this growth suppression by haptoglobin is involved in the interaction of hemoglobin with HbR, the effect of haptoglobin on the binding of hemoglobin to HbR was examined.…”

A Novel Porphyromonas gingivalis FeoB Plays a Role in Manganese Accumulation

“…The growth and virulence of P. gingivalis has been reported to be dependent on the availability of iron complexes such as heme (7)(8)(9). Growth studies have indicated that P. gingivalis preferentially acquires iron in the form of hemoglobin-derived heme, a molecule comprised of a protoporphyrin IX ring with a co-ordinated central ferrous atom (10). Unlike most bacteria P. gingivalis cannot synthesize protoporphyrin IX de novo (11,12) and must also acquire this from the environment, which may explain the preferential utilization of heme by this bacterium.…”