Interactions between bacteria and iron binding proteins

Abstract

Growth inhibition due to iron deprivation of 118 strains of staphylococci, enterobacteriaceae, Streptococcus faecalis and Bacteroides species was studied in vitro. Apo-transferrin (Tr), apo-lactoferrin (Lf) and a synthetic iron chelator (EDDA) were used as iron binding agents~ S. epidermidis was more inhibited than S. aureus. The majority of the enterobacteriaceae was inhibited by the highest concentrations of EDDA, Tr and Lf. Most bacteroides strains were inhibited by EDDA and all were inhibited by Tr and Lf at physiological concentrations. Production of bacterial iron chelators could be demonstrated in all strains growing at iron deprivation except for Streptococcus faecalis. In 8 out of Ii strains of Bacteroides cytochromes of type b and c could be demonstrated. In one strains iron deprivation resulted in disappearance of the cytochrome and a reduction of the growth yield. In Bacteroides the production of iron-chelators could not be related to virulence.

Identification of upregulated immune-related genes in Vibrio harveyi challenged Penaeus monodon postlarvae

“…Its expression is known to play a key role in maintaining iron homeostasis inside the cell [12]. Binding of free iron is considered bacteriostatic, as bacterial cell growth is inhibited if no iron is available for synthesis of essential ironcontaining compounds [12]. It may also have a role in clotting, as it has been shown in Drosophila [13].…”

“…This iron storage protein is crucial in the metabolism of iron as well as in the detoxification of this metal. Its expression is known to play a key role in maintaining iron homeostasis inside the cell [12]. Binding of free iron is considered bacteriostatic, as bacterial cell growth is inhibited if no iron is available for synthesis of essential ironcontaining compounds [12].…”

Profiling of a few immune responsive genes expressed in postlarvae of Fenneropenaeus indicus challenged with Vibrio harveyi D3

“…It was earlier reported to be upregulated following challenge with WSSV (Pan et al, 2005). Binding of free iron is considered bacteriostatic, as bacterial cell growth, in particular of Vibrionaceae, is inhibited if iron is not available for synthesis of essential iron-containing compounds (Marcelis, 1980). The high representation of ferritin transcripts indicates its upregulation due to V. harveyi challenge as was also confirmed by qPCR results.…”

Nutritional requirements of Bacteroides fragilis and Bacteroides vulgatus with reference to iron and virulence

“…were able to acquire iron in a chelator-dependent way. This property, however, was not related to a particular species nor to the virulence of the strains as measured by their isolation from abscesses or faeces [19]. The necessity for protoporphyfin IX or haemin for growth of B. vulgatus is not surprising.…”

“…The exact nature of the iron source of B. fragilis in serum is still not known. It may be haem, but transferrin iron may be another candidate, although it has been shown, that transfen'in is bacteriostatic for Bacteroides strains [19].…”