An optimum route to prepare FePO4·2H2O and its use as an iron source to synthesize LiFePO4

2013 ◽  
Vol 56 (5) ◽  
pp. 576-582 ◽  
Author(s):  
MingJuan Li ◽  
LiQun Sun ◽  
Kai Sun ◽  
RongShun Wang ◽  
HaiMing Xie
Keyword(s):  
2005 ◽  
Vol 187 (16) ◽  
pp. 5658-5664 ◽  
Author(s):  
Elizabeth E. Wyckoff ◽  
Gregory F. Lopreato ◽  
Kimberly A. Tipton ◽  
Shelley M. Payne

ABSTRACT Shigella dysenteriae serotype 1, a major cause of bacillary dysentery in humans, can use heme as a source of iron. Genes for the transport of heme into the bacterial cell have been identified, but little is known about proteins that control the fate of the heme molecule after it has entered the cell. The shuS gene is located within the heme transport locus, downstream of the heme receptor gene shuA. ShuS is a heme binding protein, but its role in heme utilization is poorly understood. In this work, we report the construction of a chromosomal shuS mutant. The shuS mutant was defective in utilizing heme as an iron source. At low heme concentrations, the shuS mutant grew slowly and its growth was stimulated by either increasing the heme concentration or by providing extra copies of the heme receptor shuA on a plasmid. At intermediate heme concentrations, the growth of the shuS mutant was moderately impaired, and at high heme concentrations, shuS was required for growth on heme. The shuS mutant did not show increased sensitivity to hydrogen peroxide, even at high heme concentrations. ShuS was also required for optimal utilization of heme under microaerobic and anaerobic conditions. These data are consistent with the model in which ShuS binds heme in a soluble, nontoxic form and potentially transfers the heme from the transport proteins in the membrane to either heme-containing or heme-degrading proteins. ShuS did not appear to store heme for future use.


Author(s):  
A.H. Ltaïef ◽  
A. Gadri ◽  
S. Ammar ◽  
A. Fernandes ◽  
M.J. Nunes ◽  
...  

2021 ◽  
Author(s):  
Arwen E Frick-Cheng ◽  
Anna Sintsova ◽  
Sara N Smith ◽  
Ali Pirani ◽  
Evan S Snitkin ◽  
...  

More than half of women will experience a urinary tract infection (UTI) with uropathogenic Escherichia coli (UPEC) causing ~80% of uncomplicated cases. Iron acquisition systems are essential for uropathogenesis, and UPEC encode functionally redundant iron acquisition systems, underlining their importance. However, a recent UPEC clinical isolate, HM7 lacks this functional redundancy and instead encodes a sole siderophore, enterobactin. To determine if E. coli HM7 possesses unidentified iron acquisition systems, we performed RNA-sequencing under iron-limiting conditions and demonstrated that the ferric citrate uptake system (fecABCDE and fecIR) was highly upregulated. Importantly, there are high levels of citrate within urine, some of which is bound to iron, and the fec system is highly enriched in UPEC isolates compared to environmental or fecal strains. Therefore, we hypothesized that HM7 and other similar strains use the fec system to acquire iron in the host. Deletion of both enterobactin biosynthesis and ferric citrate uptake (ΔentB/ΔfecA) abrogates use of ferric citrate as an iron source and fecA provides an advantage in human urine in absence of enterobactin. However, in a UTI mouse model, fecA is a fitness factor independent of enterobactin production, likely due to the action of host Lipocalin-2 chelating ferrienterobactin. These findings indicate that ferric citrate uptake is used as an iron source when siderophore efficacy is limited, such as in the host during UTI. Defining these novel compensatory mechanisms and understanding the nutritional hierarchy of preferred iron sources within the urinary tract are important in the search for new approaches to combat UTI.


Author(s):  
Fitri Maya Puspita ◽  
Yusuf Hartono ◽  
Nadia Zuliaty Syaputri ◽  
Evi Yuliza ◽  
Weni Dwi Pratiwi

<p>In this paper, the Robust Counterpart Open Capacitation Vehicle Rounting Problem (RC-OCVRP) Model has been established to optimize waste transport in districts Sako and districts Sukarami, Palembang City. This model is completed with the aid of LINGO 13.0 by using Branch and Bound solver to get the optimum route. For Sako districs, the routes are as follows: working area 1 is TPS 1-TPS 2-TPS 3-TPA with distance 53.39 km, working area 2 is TPS 1-TPS 2-TPS 3-TPA with distance 48.14 km, working area 3 is TPS 1-TPA with a distance of 22.98 km, and working area 4 is TPS 1-TPS 2-TPS 3-TPS 4-TPA with 45.45 km distance, and obtained the optimum route in Sukarami districts is as follows: working area 1 is TPS 1-TPS 2-TPA 44.39 km, working area 2 is TPS 1-TPS 2-TPS 3-TPA with distance 49.32 km, working area 3 is TPS 1-TPS 3-TPA-TPS 2-TPA with distance 58.57 km, and working area 4 is TPS 1-TPA with a distance of 24.07 km, working area 5 is TPS 1-TPS 3-TPA-TPS 2-TPS 4-TPA with a distance of 77.66 km, and working area 6 is a TPS 1-TPS 2-TPS 3-TPA with a distante 44.94 km.</p>


2021 ◽  
Author(s):  
Lindsey R. Lyman ◽  
Eric D. Peng ◽  
Michael P. Schmitt

The acquisition of hemin-iron from hemoglobin-haptoglobin (Hb-Hp) by Corynebacterium diphtheriae requires the iron-regulated surface proteins HtaA, ChtA, ChtC, and the recently identified Hb-Hp binding protein HbpA. We previously showed that a purified form of HbpA (HbpA-S), lacking the C-terminal region, was able to bind Hb-Hp. In this study, we show that the C-terminal region of HbpA significantly enhances binding to Hb-Hp. A purified form of HbpA that includes the C-terminal domain (HbpA-FL) exhibits much stronger binding to Hb-Hp than HbpA-S. Size exclusion chromatography (SEC) showed that HbpA-FL as well as HtaA-FL, ChtA-FL, and ChtC-FL exist as high molecular weight complexes, while HbpA-S is present as a monomer, indicating that the C-terminal region is required for formation of large aggregates. Growth studies showed that expression of HbpA-FL in the Δ hbpA mutant restored wild-type levels of growth in low-iron medium that contained Hb-Hp as the sole iron source, while HbpA-S failed to complement the Δ hbpA mutant. Protein localization studies in C. diphtheriae showed that HbpA-FL is present in both in the supernatant and in the membrane fractions, and that the C-terminal region is required for membrane anchoring. Purified HbpA-FL was able to enhance growth of the Δ hbpA mutant when added to culture medium that contained Hb-Hp as a sole iron source, suggesting that secreted HbpA is involved in the use of hemin-iron from Hb-Hp. These studies extend our understanding of this novel Hb-Hp binding protein in this important human pathogen. IMPORTANCE Hemoproteins, such as Hb, are an abundant source of iron in humans and are proposed to be required by numerous pathogens to cause disease. In this report, we expand on our previous studies in further defining the role of HbpA in hemin-iron acquisition in C. diphtheriae . HbpA is unique to C. diphtheriae , and appears to function unlike any previously described bacterial iron-regulated Hb- or Hb-Hp-binding protein. HbpA is both secreted and present in the membrane, and exists as a large aggregate that enhances its ability to bind Hb-Hp and promote hemin-iron uptake. Current studies with HbpA will increase our understanding of iron transport systems in C. diphtheriae .


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