Ferric Uptake Regulator Fur Is Conditionally Essential in Pseudomonas aeruginosa

Pasqua, Martina; Visaggio, Daniela; Sciuto, Alessandra Lo; Genah, Shirley; Banin, Ehud; Visca, Paolo; Imperi, Francesco

doi:10.1128/jb.00472-17

Cited by 72 publications

(60 citation statements)

References 63 publications

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“…It was concluded that pyoverdines are siderophores, which are iron-binding chelators involved in iron-transport into the cell 10 . In agreement with this function, it later turned out that the production of pyoverdines is tightly regulated in response to iron by the regulator Fur 11 12 . This review focuses on the biosynthesis and secretion of pyoverdines as summarized in Figure 1.…”

Section: A Brief History Of Pyoverdine Researchmentioning

confidence: 83%

The biosynthesis of pyoverdines

Ringel¹,

Brüser²

2018

Microb Cell

125

134

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Pyoverdines are fluorescent siderophores of pseudomonads that play important roles for growth under iron-limiting conditions. The production of pyoverdines by fluorescent pseudomonads permits their colonization of hosts ranging from humans to plants. Prominent examples include pathogenic or non-pathogenic species such as Pseudomonas aeruginosa, P. putida, P. syringae, or P. fluorescens. Many distinct pyoverdines have been identified, all of which have a dihydroxyquinoline fluorophore in common, derived from oxidative cyclizations of non-ribosomal peptides. These serve as precursor of pyoverdines and are commonly known as ferribactins. Ferribactins of distinct species or even strains often differ in their sequence, resulting in a large variety of pyoverdines. However, synthesis of all ferribactins begins with an L-Glu/D-Tyr/L-Dab sequence, and the fluorophore is generated from the D-Tyr/L-Dab residues. In addition, the initial L-Glu residue is modified to various acids and amides that are responsible for the range of distinguishable pyoverdines in individual strains. While ferribactin synthesis is a cytoplasmic process, the maturation to the fluorescent pyoverdine as well as the tailoring of the initial glutamate are exclusively periplasmic processes that have been a mystery until recently. Here we review the current knowledge of pyoverdine biosynthesis with a focus on the recent advancements regarding the periplasmic maturation and tailoring reactions.

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Section: A Brief History Of Pyoverdine Researchmentioning

confidence: 83%

The biosynthesis of pyoverdines

Ringel¹,

Brüser²

2018

Microb Cell

125

134

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“…Iron Uptake and A. baumannii Virulence Infection and Immunity Measurement of intracellular iron content. Intracellular iron content was measured according to a procedure described previously (62). Briefly, cells grown in M9 supplemented with 20 M FeCl 3 were collected by centrifugation, washed twice with saline, diluted in 200 ml of M9 supplemented with 1 M FeCl 3 to an optical density at 600 nm (OD 600 ) of 0.05, and incubated for 60 h at 37°C with shaking at 200 rpm.…”

Section: Methodsmentioning

confidence: 99%

Contribution of Active Iron Uptake to Acinetobacter baumannii Pathogenicity

et al. 2019

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Acinetobacter baumannii is an important nosocomial pathogen. Mechanisms that allow A. baumannii to cause human infection are still poorly understood. Iron is an essential nutrient for bacterial growth in vivo, and the multiplicity of iron uptake systems in A. baumannii suggests that iron acquisition contributes to the ability of A. baumannii to cause infection. In Gram-negative bacteria, active transport of ferrisiderophores and heme relies on the conserved TonB-ExbB-ExbD energytransducing complex, while active uptake of ferrous iron is mediated by the Feo system. The A. baumannii genome invariably contains three tonB genes (tonB1, tonB2, and tonB3), whose role in iron uptake is poorly understood. Here, we generated A. baumannii mutants with knockout mutations in the feo and/or tonB gene. We report that tonB3 is essential for A. baumannii growth under iron-limiting conditions, whereas tonB1, tonB2, and feoB appear to be dispensable for ferric iron uptake. tonB3 deletion resulted in reduced intracellular iron content despite siderophore overproduction, supporting a key role of TonB3 in iron uptake. In contrast to the case for tonB1 and tonB2, the promoters of tonB3 and feo contain functional Fur boxes and are upregulated in iron-poor media. Both TonB3 and Feo systems are required for growth in complement-free human serum and contribute to resistance to the bactericidal activity of normal human serum, but only TonB3 appears to be essential for virulence in insect and mouse models of infection. Our findings highlight a central role of the TonB3 system for A. baumannii pathogenicity. Hence, TonB3 represents a promising target for novel antibacterial therapies and for the generation of attenuated vaccine strains.

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“…The effect of iron on the growth of K. pneumoniae was measured following previous methods with some modifications [18,19]. In brief, overnight cultures of all K. pneumoniae clinical isolates (FK3065, FK3087, FK3170, FK3226, FK3992, FK4003) and K. pneumoniae ATCC 700603 were diluted 1:100 in Luria-Bertani (LB) broth supplemented with different iron concentrations (50 μM, The biofilm assay was performed as published with some modifications [20].…”

Section: Growth Curves and Biofilm Formationmentioning

confidence: 99%

Effects of iron on the growth, biofilm formation and virulence of Klebsiella pneumoniae causing liver abscess

et al. 2020

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Background: Klebsiella pneumoniae is considered the most clinically relevant species of Enterobacteriaceae, known to cause severe infections including liver abscesses. To the best of our knowledge, a large proportion of iron in the human body is accumulated and stored in the liver. We hypothesize that increased iron availability is an important factor driving liver abscess formation and we therefore aim to understand the effects of iron on K. pneumoniae causing liver abscesses. Results: All tested K. pneumoniae clinical isolates, including those isolated from liver abscesses and other abdominal invasive infection sites, grew optimally when cultured in LB broth supplemented with 50 μM iron and exhibited the strongest biofilm formation ability under those conditions. Decreased growth and biofilm formation ability were observed in all tested strains when cultured with an iron chelator (P < 0.05). The infection model of G. mellonella larvae indicated the virulence of liver abscess-causing K. pneumoniae (2/3) cultured in LB broth with additional iron was significantly higher than those under iron-restricted conditions (P < 0.05). The relative expression levels of the four siderophore genes (iucB, iroB, irp1, entB) in K. pneumoniae strains isolated from liver abscesses cultured with additional iron were lower than those under iron-restricted conditions (P < 0.05).Conclusions: It is suggested by our research that iron in the environment can promote growth, biofilm formation and enhance virulence of K. pneumoniae causing liver abscesses. A lower expression of siderophore genes correlates with increased virulence of liver abscess-causing K. pneumoniae. Further deeper evaluation of these phenomena is warranted.

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Ferric Uptake Regulator Fur Is Conditionally Essential in Pseudomonas aeruginosa

Cited by 72 publications

References 63 publications

The biosynthesis of pyoverdines

The biosynthesis of pyoverdines

Contribution of Active Iron Uptake to Acinetobacter baumannii Pathogenicity

Effects of iron on the growth, biofilm formation and virulence of Klebsiella pneumoniae causing liver abscess

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