Oxygen-dependent Oxidation of Fe(II) to Fe(III) and Interaction of Fe(III) with Bovine Serum Albumin, Leading to a Hysteretic Effect on the Fluorescence of Bovine Serum Albumin

Xu, Xiao-lei; Zhang, Liyun; Shen, Dengke; Wu, Hao; Liu, Qingliang

doi:10.1007/s10895-007-0263-4

Cited by 42 publications

(21 citation statements)

References 39 publications

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“…Previously, it was reported that serum albumin had binding affinity to free iron, heme, or transferrin (15,36). However, this is the first report to demonstrate that iron capture by serum albumin affects the expression of a virulence factor(s) in S. aureus.…”

Section: Vol 77 2011 Expression Of Virulence Factors By S Aureus Imentioning

confidence: 86%

Expression of Virulence Factors by Staphylococcus aureus Grown in Serum

Oogai

Matsuo

Hashimoto

et al. 2011

Appl Environ Microbiol

127

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Staphylococcus aureus produces many virulence factors, including toxins, immune-modulatory factors, and exoenzymes. Previous studies involving the analysis of virulence expression were mainly performed by in vitro experiments using bacterial medium. However, when S. aureus infects a host, the bacterial growth conditions are quite different from those in a medium, which may be related to the different expression of virulence factors in the host. In this study, we investigated the expression of virulence factors in S. aureus grown in calf serum. The expression of many virulence factors, including hemolysins, enterotoxins, proteases, and iron acquisition factors, was significantly increased compared with that in bacterial medium. In addition, the expression of RNA III, a global regulon for virulence expression, was significantly increased. This effect was partially restored by the addition of 300 M FeCl 3 into serum, suggesting that iron depletion is associated with the increased expression of virulence factors in serum. In chemically defined medium without iron, a similar effect was observed. In a mutant with agr inactivated grown in serum, the expression of RNA III, psm, and sec4 was not increased, while other factors were still induced in the mutant, suggesting that another regulatory factor(s) is involved. In addition, we found that serum albumin is a major factor for the capture of free iron to prevent the supply of iron to bacteria grown in serum. These results indicate that S. aureus expresses virulence factors in adaptation to the host environment.Staphylococcus aureus is one of the major pathogens of humans; it causes various suppurative diseases, food poisoning, pneumonia, and toxic shock syndrome (11,20). In addition, S. aureus, especially methicillin-resistant S. aureus (MRSA), often causes serious problems via nosocomial infection in hospitals (10, 16). Furthermore, community-acquired MRSA has recently emerged and has been reported to cause serious infectious diseases, sepsis, and pneumonia (3, 9).It is well known that S. aureus produces many virulence factors, such as hemolysins, leukocidins, proteases, enterotoxins, exfoliative toxins, and immune-modulatory factors (11,12,21,31). The expression of these factors is tightly regulated during growth. The agr system, known as the quorum-sensing system, is known to play a central role in the regulation of virulence factors (5,26,27). AgrAC is a two-component system (TCS) that consists of a histidine kinase and a response regulator. The Agr system regulates the expression of the gene coding for small RNA, known as RNA III, which is localized divergently at the agr operon and regulates the expression of many virulence factors, such as hemolysins, leukocidins, and protein A (26, 27). In addition, RNA III, known as hld, encodes delta-hemolysin. The mechanisms of RNA III regulation for the expression of several virulence factors and regulatory factors, including alpha-hemolysin, coagulase, protein A, Map, and Rot, have been demonstrated to occur at the posttran...

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Section: Vol 77 2011 Expression Of Virulence Factors By S Aureus Imentioning

confidence: 86%

Expression of Virulence Factors by Staphylococcus aureus Grown in Serum

Oogai

Matsuo

Hashimoto

et al. 2011

Appl Environ Microbiol

127

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“…HSA is usually reported as a low-affinity Fe(III)-binding protein. Nevertheless, values for HSA-Fe(III) dissociation equilibrium constant(s) have not been reported, although a single site with K d = 3.5 Â 10 À8 M was reported for the Fe(III)-bovine serum albumin complex (BSA-Fe(III)) (Xu et al, 2008). Interestingly, Fe(III) does not compete with Ca(II) for its HSA binding site (Silva and Hider, 2009).…”

Section: Other Metal Binding Sitesmentioning

confidence: 99%

Human serum albumin: From bench to bedside

Fanali

Masi

Trezza

et al. 2012

Molecular Aspects of Medicine

1,473

1,452

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“…Fe 3+ ions are transported in plasma mainly by a non-heme iron-binding glycoprotein transferrin, which composes ~7-10% of plasma protein (37). Iron can denature proteins in general and albumin in particular (38,39).…”

Section: +mentioning

confidence: 99%

Unusual clotting dynamics of plasma supplemented with iron(III)

Jankun

Landeta

Pretorius

et al. 2013

International Journal of Molecular Medicine

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Abstract. Iron salts are used in the treatment of iron deficiency anemia. Diabetic patients are frequently anemic and treatment includes administration of iron. Anemic patients on hemodialysis are at an increased risk of thromboembolic coronary events associated with the formation of dense fibrin clots resistant to fibrinolysis. Moreover, in chronic kidney disease patients, high labile plasma iron levels associated with iron supplementation are involved in complications found in dialyzed patients such as myocardial infarction. The aim of the present study was to investigate whether iron treatment is involved in the formation of the fibrin clots. Clotting of citrated plasma supplemented with Fe 3+ was investigated by thromboelastometry and electron microscopy. The results revealed that iron modifies coagulation in a complex manner. FeCl 3 stock solution underwent gradual chemical modification during storage and altered the coagulation profile over 29 days, suggesting that Fe 3+ interacts with both proteins of the coagulation cascade as well as the hydrolytic Fe 3+ species. Iron extends clotting of plasma by interacting with proteins of the coagulation cascade. Fe 3+ and/or its hydrolytic species interact with fibrinogen and/or fibrin changing their morphology and properties. In general FeCl 3 weakens the fibrin clot while at the same time precipitating plasma proteins immediately after application. Fe 3+ or its derivatives induced the formation of insoluble coagulums in non-enzymatic reactions including albumin and transferrin. Iron plays a role in coagulation and can precipitate plasma proteins. The formation of coagulums resistant to lysis in non-enzymatic reactions can increase the risk of thrombosis, and extending clotting of plasma can prolong bleeding.

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Oxygen-dependent Oxidation of Fe(II) to Fe(III) and Interaction of Fe(III) with Bovine Serum Albumin, Leading to a Hysteretic Effect on the Fluorescence of Bovine Serum Albumin

Cited by 42 publications

References 39 publications

Expression of Virulence Factors by Staphylococcus aureus Grown in Serum

Expression of Virulence Factors by Staphylococcus aureus Grown in Serum

Human serum albumin: From bench to bedside

Unusual clotting dynamics of plasma supplemented with iron(III)

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