Research and Progress on the Mechanism of Iron Transfer and Accumulation in Rice Grains

Iron (Fe) is one of the most important micronutrients for organisms. Currently, Fe deficiency is a growing nutritional problem and is becoming a serious threat to human health worldwide. A method that could help alleviate this “hidden hunger” is increasing the bioavailable Fe concentrations in edible tissues of major food crops. Therefore, understanding the molecular mechanisms of Fe accumulation in different crop tissues will help to develop crops with higher Fe nutritional values. Biofortification significantly increases the concentration of Fe in crops. This paper considers the important food crop of rice (Oryza sativa L.) as an example and highlights recent research advances on the molecular mechanisms of Fe uptake and allogeneic uptake in different tissues of rice. In addition, different approaches to the biofortification of Fe nutrition in rice and their outcomes are described and discussed. To address the problems that occur during the development and application of improving nutritional Fe in rice, technical strategies and long-term solutions are also proposed as a reference for the future improvement of staple food nutrition with micronutrients.

Identification of the Root Causes for Blowhole Defect in Castings Using Quantitative Risk Ishikawa Diagrams

The primary objective of this work is to reduce blowhole defect occurring in a cast iron transfer box. The transfer box moulds were produced using green sand moulding process, and cores were made using CO2 process. It was found that the transfer box had a rejection rate as high as 60%, and it was mainly due to a blowhole on the top surface of the casting. The Ishikawa and risk Ishikawa diagrams were used to analyze this major defect. The risk Ishikawa diagram was constructed by assigning weights to the major and sub-causes due to which the defect occurs. Further, the probability of risk and its impact values were employed to compute risk scores for the main causes and also global risk. From the work carried out, it was found that that the moulds and the sands along with melting and pouring parameters were the major causes for this defect while damp chill, pouring delays and high moisture content in sand were identified as the root causes for the blowhole defect. The main root cause for the blowhole defect was pouring delay that eventually causes dampness in the chill pieces kept inside the moulds. The remedial measures of keeping the moisture content of the sand within 3.5% and pouring the moulds in the shift II within half an hour after closing them were implemented to eliminate it.

A Comparison of Two Novel Non-Ferrous Metal Recovery Equations: Development, Similarity and Industrial Significance

The recovery of non-ferrous metals in oxidative sulfide smelting and converting processes and within reductive oxide smelting processes has been previously analyzed using two similar equations which express recovery in terms of iron transfer and a distribution coefficient. A detailed comparison will show that the equations are mathematically identical but with one equation validated only for constant distribution coefficients. The wider applicability of the equation and implications for optimization of metal recovery are discussed.

Compared to Normal-Weight Pregnant Women, Overweight Pregnant Women Fail to Upregulate Iron Absorption in the Third Trimester Despite Iron Deficiency and Their Infants Are Born with Lower Body Iron Stores

Introduction: Overweight/obesity (OWOB) causes low-grade systemic inflammation which induces hepcidin and a reduces fractional iron absorption (FIA) even when iron stores are low. Pregnancy increases iron needs because of the expansion of maternal blood volume and fetal needs. It is unclear whether and/or to what extent OWOB during pregnancy influences FIA, iron supply of the fetus and risk of iron deficiency in mother and newborn. In this study, we (1) determined the impact of maternal OWOB on FIA in pregnancy and on the transfer of iron to the fetus and newborn iron status; (2) confirmed the relationship between BMI, hepcidin, serum ferritin (SF) and inflammatory markers. Methods: In this prospective experimental multi-center case-control study (normal-weight (NW) n=40; OWOB n=37) we administered labeled [57Fe]- or [58Fe]-FeSO4 to women during the 2nd and 3rd trimester of pregnancy. We measured FIA by determining erythrocyte incorporation of iron stable isotopes 14 days after administration. From pregnancy week (PW) 12 until PW 36, iron-, inflammation and hepcidin were monitored. Iron transfer to the fetus was determined isotopically as the concentration of circulating iron in the infant aged three days. We assessed iron status in infants born to NW (n=29) and OWOB (n=31) at age three days, three months and six months. Results: Subject characteristics in PW 12 for the NW/OWOB were: mean (±SD) age: 29±6/ 30±6 years, median (IQR) pre-pregnancy BMI: 21.6 (20.3-23.7)/ 31.6 (28.4-35.9) kg/m2 (p<0.001), mean (±SD) hemoglobin: 12.3±1.1/ 12.4±0.9 g/dL, median (IQR) SF: 27.7 (17.3-48.2)/ 30.6 (16.6-64.4) µg/L and median (IQR) interleukin-6: 1.41 (1.03-1.95)/ 2.37 (1.91-3.85) pg/ml (p<0.001). Independent sample t-test showed no difference in FIA between NW and OWOB in the 2nd trimester with median FIA (IQR) 12.3 (7.2-20.6) and 10.1 (6.9-17.2) % (p=0.788). Despite the OWOB had ≈30% lower body iron stores (BIS) and comparable hepcidin concentrations to the NW in the 3rd trimester, FIA was significantly higher in the NW compared to the OWOB with median FIA (IQR) 22.3 (10.6-33.8) and 12.7 (10.4-18.1) % (p=0.042). In the NW, FIA was upregulated by 80% in the 3rd trimester compared to the 2nd trimester, whereas in the OWOB FIA, it was only upregulated by 25%. Linear mixed effect model analysis (LMM) showed a significant group-effects on weight, IL-6 and CRP throughout pregnancy (all p<0.05), but surprisingly no group-effect on hepcidin. In multiple regression analysis, the main predictor of hepcidin throughout pregnancy was BIS, not inflammation. Iron transfer to the newborn was non-significantly higher in the NW compared to the OWOB with mean (±SD) circulating iron in the newborn at age three days 136.6 ± 42.7 and 126.3 ± 32.4 mg. LMM on infant BIS and on infant serum transferrin receptor (sTfR) over the first six months showed significant group (p=0.024, p=0.046) and time-effects (both p<0.001) with lower BIS and higher sTfR in infants born to OWOB. Median (IQR) BIS at age six months were 7.7 (6.3-8.8) and 6.6 (4.6-9.2) mg/kg bodyweight in infants born to NW and OWOB. Conclusion: In normal pregnancy, FIA increases over time to support increased iron needs of mother and fetus. Our data show a dramatically reduced increase in FIA in OWOB pregnant women in the 3rd trimester, despite low BIS and low hepcidin, and this results in less iron transfer to the fetus. Future molecular studies are needed to clarify the mechanism of reduced FIA and fetal iron transfer in OWOB. To our knowledge, this is the first study assessing the impact of maternal OWOB on infant iron status at multiple time points over the first six months. Our findings strongly argue for careful monitoring of iron status in OWOB pregnancy and for defining a more effective iron supplementation regimen for this population group. Prevalence of anemia in pregnancy and infancy is high, especially in low and middle income countries and is often associated with severe health consequences. If iron status of OWOB pregnant women and their infants could be improved by optimizing iron supplementation guidelines for OWOB, this could have major benefits. Disclosures No relevant conflicts of interest to declare.

Maternal iron absorption and iron transfer to the fetus during pregnancy in normal- weight and overweight/obese women

Overweight/obesity (owob) causes low-grad systemic inflammation and thereby an up-regulation of hepcidin and a reduction in fractional iron absorption (FIA) even with low iron stores. Pregnancy increases iron needs because of the expansion of maternal blood volume and fetal needs. It is unclear to what extent owob pregnancy influences FIA, iron supply of the fetus and risk of iron deficiency. Therefore, the main aim of this study was to determine the effect of maternal owob on iron absorption during pregnancy and on the iron transfer to the fetus. Secondary objectives were to investigate the development of hepcidin, plasma ferritin and inflammatory markers over the course of pregnancy dependent on weight status. In this multicenter case-control study we included 44 normal weight (nw) and 36 owob women around pregnancy week (PW) 12. We administered 57Fe or 58Fe labeled FeSO4 to women during the 2nd and 3rd trimester of pregnancy. We measured FIA determining erythrocyte incorporation of iron stable isotopes 14 days after administration. From PW 12 until PW 36 iron-, inflammation and hepcidin were monitored. Iron transfer to the fetus was determined as iron stable isotope concentration in cord blood. Sample analysis is currently ongoing, all results will be available in October. Subject characteristics in PW 12 for the nw (n = 26) and owob (n = 10) were: mean BMI: 21.4 ± 2.2 and 36.7 ± 6.8 kg/m2, mean hemoglobin: 12.4 ± 1.2 and 12.4 ± 0.9 g/dL and median plasma ferritin: 41.3 (29.6–83.6) and 61.6 (24.3–119.0) μg/L. Preliminary results indicate FIA increased by 2.4 fold in the nw and by 1.3 fold in the owob women between the 2nd and the 3rd trimester of pregnancy. Iron stores decreased in both groups over the course of pregnancy. Hepcidin was still significantly higher in the owob women in the 3rd trimester. Inflammation tended to be higher in owob women throughout pregnancy. Iron isotopes were highly detectable in cord blood. The 58Fe:57Fe-ratio determined in cord blood corresponded to the 58Fe:57Fe-ratio determined in the mother in the 3rd trimester. Thus, in owob women, the increase in FIA throughout pregnancy to support iron needs of mother and fetus is blunted compared to nw women. This is consistent with elevated hepcidin in the 3rd trimester and higher inflammation throughout pregnancy. Thus, even though iron demands are strongly increased, owob may prohibit an adequate iron supply to the expecting mother and the fetus due to persistent subclinical inflammation.

Endosome–mitochondria interactions are modulated by iron release from transferrin

Transient “kiss and run” interactions between endosomes containing iron-bound transferrin (Tf) and mitochondria have been shown to facilitate direct iron transfer in erythroid cells. In this study, we used superresolution three-dimensional (3D) direct stochastic optical reconstruction microscopy to show that Tf-containing endosomes directly interact with mitochondria in epithelial cells. We used live-cell time-lapse fluorescence microscopy, followed by 3D rendering, object tracking, and a distance transformation algorithm, to track Tf-endosomes and characterize the dynamics of their interactions with mitochondria. Quenching of iron sensor RDA-labeled mitochondria confirmed functional iron transfer by an interacting Tf-endosome. The motility of Tf-endosomes is significantly reduced upon interaction with mitochondria. To further assess the functional role of iron in the ability of Tf-endosomes to interact with mitochondria, we blocked endosomal iron release by using a Tf K206E/K534A mutant. Blocking intraendosomal iron release led to significantly increased motility of Tf-endosomes and increased duration of endosome–mitochondria interactions. Thus, intraendosomal iron regulates the kinetics of the interactions between Tf-containing endosomes and mitochondria in epithelial cells.

The Role of Hepcidin in Health And Disease

Imbalances of iron homeostasis account for some of the most common human diseases. Pathologies result from both, iron deficiency or overload and frequently affect the hepcidin/ferroportin regulatory system that balances systemic iron metabolism. The small hepatic peptide hormone hepcidin orchestrates systemic iron fluxes and controls plasma iron levels by binding to the iron exporter ferroportin on the surface of iron releasing cells, triggering its degradation and hence reducing iron transfer to transferrin. Hepcidin thus maintains transferrin saturation at physiological levels assuring adequate iron supplies to all cell types. My presentation will focus on mechanisms that control hepcidin and ferroportin expression as well as on pathologies that arise when this key regulatory circuitry underlying systemic iron homeostasis is disrupted. Disclosures No relevant conflicts of interest to declare.

THE CORROSION BEHAVIOR OF WEATHERING STEEL UNDER DIFFERENT CORROSIVE ENVIRONMENTS

Weathering steel is a kind of steel that can reduce the corrosion rate by generating a dense protective rust on the steel surface that exerts anti-corrosion performance. Exposure tests of weathering steel with saltwater spraying were performed under three different conditions. When the consistency of sodium chloride solutions was small (0.5% and 1.0%), the effect of rain rinse was observed. However, large consistencies of sodium chloride solutions provided small differences in rust thickness between open air and under roof conditions. From the results of iron transfer resistance measurements, it was observed that protective rust was generated only in a few cases. This result indicated that generation of protective rust was strongly dependent on the corrosive environment. From the results of exposure tests, it became clear that the change of rust thickness with time can be estimated as an exponential function. The constants in the exponential function can be expressed as a function of consistency of sodium chloride solutions.